PDD & PPD

The client would like to create a feature wall near the entrance of the library to showcase new books and staff picks. You have specified fixture T2a. The fixture will be mounted on a track suspended 6ft off of the ceiling at level one. How far apart should the fixtures be spaced from one another when you lay them out along the wall in order to maintain a minimum of 30fc at level one?

21ft (ceiling height) - 6ft (fixture height from ceiling) = 15ft mounting height Beam diameter at 50% CBCP = 6.7ft CBCP = 7510, according to the specifications by model number chart, 50% = 3755 Footcandles = 0.4% x 3755 = 15fc So, space the fixtures 3.35ft apart so the beam diameters overlap to create 30fc

Sanitary sewage disposal: DWV system: drain piping - sealing and venting

A DWV system must be sealed off from the air to prevent sewer gases from escaping into a building's interior. This is usually accomplished by water seals in fixture traps. A DWV system must, however, be open to the outside air to maintain atmospheric pressure within the system, both to aid in the flow of materials through it and to protect the trap seals from being disturbed. This is usually accomplished through a network of vents.

Siding - double coursing

A method of applying shingles over an undercourse of lower-grade shingles or other suitable material. Nails are exposed as a result of face (butt) nailing, and greater shingle exposures are possible than with single coursing. Double coursing usually results in greater wall coverage at lower cost.

Sabin

A unit of sound absorption. One square foot of 100 percent absorbing material = 1 sabin. Used for calculating the reverberation time of theaters, concert halls, recording studios, etc.

Water-cement ratio

A water-cement ratio of 0.31 could be thought of as 0.31 lb of water for each pound of cement. A water-cement ratio ranging from 0.35-0.80 is usually maintained for the sake of workability and placeability. Another advantage of using more water is that more aggregate can be used, with resulting economy.

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Access doors and panels and their frames are constructed of galvanized or stainless steel. Floor hatches are usually made of aluminum or steel.

Carpet yarn dyeing methods: space dyeing

Both staple and continuous filament yarns can be space dyed in alternating bands of color, generally for use in multicolored tufted carpet. In the knit sleeve method of space dyeing, the yarn is knitted into a fabric, print rollers apply the desired colors, and then the fabric in unraveled again into yarn. In the warp print method, parallel yarns are fed continuously into a machine where color is applied by rollers.

Softwood: west coast hemlock

Both the heartwood and sapwood of western hemlock are almost white with a pinkish tinge and with very little contrast, although the sapwood is sometimes lighter in color.

Closed-loop (geothermal)

Closed-loop is a term used to describe a geothermal heat pump system with a continuous loop of plastic pipe as the heat exchanger. It is a "closed" system where water or antifreeze recirculates through the pipes. The loops can be either vertical (drilled) pipes or horizontal (trenched) pipes, depending on site conditions. Closed loops can also be installed in ponds and lakes.

Cork tile

Cork tile is composed chiefly of the granulated bark of the cork oak tree, native to Spain, Portugal, and North Africa. Synthetic resins area added to the granulated cork, and the mixture is pressed into sheets or blocks and baked. Surfaces are finished with a protective coat of wax, lacquer, or resin applied under heat and pressure. Sheets then are cut to tile sizes. Vinyl cork tile has a film of clear PVC vinyl fused to the top surface to improve durability, water resistance, and ease of maintenance.

Extruded aluminum doors, frames, and storefronts - design requirements

Design pressure is determined using the fastest wind speed likely to be encountered at a building's location.

Drainage board

Dimpled plastic sheet material applied along the vertical face of a foundation wall. The dimpled side is placed toward the foundation wall, creating a 1/2-inch (typically) cavity in which water from above can travel to drains at the foundation footing.

Thermal properties of components: conductivity

Each material has a characteristic rate as which heat will flow through it. For homogeneous solids this is called conductivity (designated as k), and in the inch-pound system it is the number of British thermal units per hour (Btu/h) that flow through 1 square foot of material that is 1 in thick when the temperature difference across that material is 1 degree F (under conditions of steady heat flow).

Aquifer thermal energy storage

Energy-efficient method to heat and cool a building through the storage and recovery of thermal energy from groundwater in an aquifer. Cold groundwater is collected in winter months and stored for use in the warm months, and vice versa. The cold water that is used and subsequently warmed can also be stored as warm water for cool months.

Wall flashing - base of walls

Flashing and damp checks are used at the base of walls. Flashing diverts to the exterior moisture that enters the wall above the flashing location. A damp check stops the upward capillary travel of ground moisture. If installed properly, metal shields used for termite protection may serve these purposes.

Carpet durability: alkali and resistance

Foods and beverages are generally mildly alkaline or acid in nature; many soaps and detergents are strongly alkaline.

Ionization detectors

Gaseous ionization detectors are radiation detection instruments used in particle physics to detect the presence of ionizing particles and in radiation protection applications to measure ionizing radiation.

Forced air systems

HVAC system which uses air as a heat transfer medium. Air is tempered as it is blown by a fan across a heat exchanger, and distributed throughout a building by a network of ducts and plenums.

Out-of-plane offsets: discontinuous shear walls

In elevation, this failure pattern would be caused by a shear wall not continuing the entire face of the plane, resulting in collapse in extreme circumstances of seismic occurrences.

Restrained vs. unrestrained

In regard to fire-rated floor assemblies, restrained and unrestrained refer to whether a floor is connected to a supporting structure in a way that allows for it to expand longitudinally when subjected to fire. In other words, in a restrained assembly, the structure around the floor beams can withstand thrust from thermal expansion of the floor beams.

Linoleum

Linoleum consists of a blend of oxidized linseed oil binders, rosins, wood flour, and cork flour fillerd bonded to burlap, felt, juice, or polyester backing. Linoleum is available in sheet and tile form.

Open-loop (geothermal)

Open-loop describes a geothermal heat pump system that uses a well or surface water for source fluid and discharges to the surface or groundwater. It is also known as a pump-and-dump or once-through.

Preparation for wood and other board siding

Overlap for bevel siding should be not less than 1". Lap for drop siding and diagonal and vertical siding is dictated by the profile of the boards. Nails may be either aluminum, stainless steel, or hot-dip galvanized. The preferred material is No. 304 stainless steel for most locations, with No. 316 being used in seacoast locations. Other nail materials should not be used.

Thin-film photovoltaics

PV devices made of a semiconductor material, such as copper indium diselenide or amorphous silicon, a few micrometers thick deposited on substrates of glass, ceramic, or another compatible material.

PTAC

Packaged terminal air conditioner. A self-contained thru-the-wall HVAC unit commonly found in hotels, hospitals, and condos.

Portland cement plaster application

Sometimes three-coat applications are used over concrete and masonry bases, especially where increased strength or thickness is required. Usually, however, two-coat applications give sufficient strength and durability over such solid bases. In two-coat applications, a single base coat takes the place of the scratch and brown coats and is followed by a finish coat. The total thickness should be at least 5/8". Except when a chemical bonding agent is used, a surface to be plastered should be dampened to ensure uniform suction. A 3/8" thick base coat is then applied. It is not scratched, as in a three-coat application. Mechanical bond for the finish coat is provided by rough floating of the base coat in the same manner as the brown coat in the three-coat work. A machine-applied base coat is built up with several applications, with the final application being rodded and darbied manually. A finish coat should be about 1/4" thick. It can be applied in a variety of textures by hand or machine as in a three-coat application.

Sound in interior planning

Sound control should create an environment that is acoustically comfortable, not to render rooms soundproof. The basic principles of such planning include 1. locating occupied spaces as far as possible from noise sources, 2. separating noisy areas from quiet areas by isolating the noise source or using buffer spaces, 3. eliminating air paths that permit sound to travel between spaces, especially through the design, sizing, and placement of doors and windows, and 4. reducing the noise level at the source by selecting mechanical equipment and appliances that operate quietly. Room proportions can be planned to reduce sound transmission. The higher the ratio of common wall to floor area, the more sound the common wall will transmit.

Recommendations for reducing the amount of electricity consumed by pumps:

1. Design systems with lower capacity and total head requirements. (using larger pipe sizes and minimizing the elevation of tanks are examples.) 2. Avoid excessive capacity. It is typically less expensive to add pumping capacity later on if needs increase. Operating a smaller pump closer to its capacity saves energy compared to a larger pump operating well under its capacity. 3. Select the most efficient pump type and size, even if its first cost is greater; life-cycle costs are likely to be lower. 4. Use two (or more) smaller pumps instead of one large one so that excess pump capacity can be turned off. 5. Maintained pumps and system components in virtually new condition to avoid efficiency loss.

Two properties give plywood superior bracing qualities

1. high shear strength in all directions for loads applied perpendicular to the panel faces and 2. relatively high nail-bearing strength, allowing nails to be driven as close as 1/4" from the edge of a panel. Splitting is virtually impossible lengthwise or crosswise since no cleavage plane exists.

Flexible flashing

Term used to describe a broad category of nonmetallic flashing, including peel-and-stick and nonstick flashing. Typically used to seal the perimeter of openings within a wall assembly (windows, doors), but it can be used along the base of walls, parapets, and corners of buildings. The inherent flexibility of the material allows it to conform to unusual shapes and angles.

Built-up membrane roofing - felt sheet construction

The felt sheets are saturated with asphalt or coal tar saturants to form saturated felts. Saturated felts are made in several wrights; the most common are No. 15 and No. 30, weighing about 15 and 30 lb er square, respectively. Glass mats are impregnated with asphalt and surfaced with a parting agent (sand, talc, or soap to prevent sticking in the roll) to form fiberglass ply felts. Coated sheets are saturated/impregnated felts that have been coated on one or both sides with additional asphalt that are then surfaced on one or both sides with a fine mineral material to prevent adhesion before application. These are generally used as base sheets in built-up roofing systems. Cap sheets and prepared roll roofing materials are saturated and coated with asphalt and are covered on the top surface with fine decorative mineral granules to help protect the asphalt from the sun. Some of these products are combination products made of layers of glass felt, organic felt, or both.

Glass heat & chemical treatments: Heat strengthening

The heat treatment known as heat strengthening is also used to increase the strength of flat glass. It involves heating the glass and then cooling it in a manner similar to that used in tempering. However, heat strengthening produces lower surface compression stresses in the glass than the tempering process. Therefore, heat-strengthened glass is only about twice as strong as annealed glass of the same thickness.

Sound quality

The quality of a tone is determined by the distribution of its numerous frequencies. Higher-frequency components are called harmonics or overtones when they are exact multiples of the fundamental frequency. The distribution and relative intensity of the overtones f a musical sounds determine the quality (timbre) of the sound.

Reverberation time

The reverberation time of a room is the time in seconds required for a sound to die out to an intensity one millionth of the intensity it had at the moment the source was stopped. On the decibel scale this is a drop of 60 dB. The reverberation time (T) of a room depends only on its size (volume, V) and sound-absorbing properties (absorption units, a), not on the power of the source. Speech intelligibility becomes poorer as loudness decreases or as reverberation time increases.

Softwood: Douglas fir

The sapwood of Douglas fir is creamy white. The heartwood is reddish-brown, and as in southern pine, the contrast in color between the two is not so pronounced as to be objectionable in a finished floor. Pieces containing both heartwood and sapwood are permitted in all grades.

Water tube boilers

The water to be heated is taken through tubes that are surrounded by the boiler's fire. They hold less water than the fire tube models, and so respond faster and can generate steam (where desired) at higher pressures.

Special coatings

Thick, high-performance, field-applied architectural coatings such as high-build glaze coatings, fire-retardant coatings, industrial coatings such as those used in sewage disposal plants, and cementitious coatings.

Design strategies for cooling: Evaporative cooling

This design strategy relies on the principle that when moisture is added to air, relative humidity increases while dry-bulb temperature decreases. (On the bioclimatic chart, this pattern exactly follows the constant wet-bulb line, upward and to the left.) In conditions that area more uncomfortably hot, higher humidity is gladly exchanged for lower air temperature. However, large quantities of both water and outdoor air are needed: fan-driven evaporative coolers are the most common way to provide this kind of cooling. Evaporative cooling imposes few constraints on designers because the equipment resembles conventional HVAC systems. Rather high indoor air velocities and their associated sounds are typical of these systems, and the aroma of the wetted material of the cooler is often noticeable. The coolest air will be in the vicinity of the air inlet to the space, the warmest air at the outlet from the space.

Concrete mixtures

What are the ingredients in a concrete mixture??

Disinfection

a. Chlorination b. Chloramine c. Ozonation d. Ultraviolet radiation e. Nanofiltration

Staking

is a method of joining flat materials by foldover tabs inserted through matching slots in the elements to be joined.

Cold-forming of iron & steel products

operations are performed on most flat-rolled and tubular products by shaping, bending, or drawing the metal beyond its yield point so that a permanent set is achieved. The most common cold-forming methods are roller, stretch, shear, brake forming, and deep drawing.

Hot-forming of iron & steel products

operations are used on metals too thick or too hard to be formed cold. These operations include 1. forging; 2. high-temperature forming (electroforming), which uses heat generated by the resistance of the workpiece to an electric current passes through it by the forming roll; and 3. high-energy rate forming, a method of hot (sometimes cold) shaping of materials by the sudden impact of a small explosive charge, a shock wave generated by an electric spark in a fluid, or sudden release of a compressed gas through a system of valves.

Forming Walls

p. 79-80

Hardwood trees

which are broad-leaved, are called deciduous because they shed their leaves at the end of each growing season, except in warmer climates.

Types of reinforcement of plaster

- Expanded metal lath - Wire lath p.647-648

Coatings

Applied only in the shop or factory; similar in materials and formula to paint; either air-drying or baked-on; include materials as Kynar coatings on metal, anodizing on aluminum, and baked enamel on lockers or furniture.

Wall flashing

Except in areas of very slight exposure to precipitation where local experience supports omitting it, flashing should be installed in other types of walls at the following locations: 1. at the bottom of walls, 2. under wall opening sills, 3. over wall opening heads, 4. at intermediate floor lines, depending on construction type, 5. where a wall penetrates a roof surface, 6. beneath copings, and 7. at expansion joints.

PV module

The smallest complete, environmentally protected assembly of PV cells and other components normally sold by a manufacturer; comprised of several (or many) PV cells.

Interior primers: wood primres

- enamel undercoaters - clear wood sealers - wood fillers p. 788-789

Exterior primers: wood primers

- oil primers - alkyd primers p.789

Interior primers: masonry and concrete wall primers and fillers

- primers - block fillers - cement grout p. 789

Fan-coil with supplementary air

Another familiar piece of below-window equipment is the fan-coil, which moves the room air as it provides either heating or cooling. Centrally conditioned, tempered fresh air is brought to the space in a constant-volume stream; the fan moves both fresh and room air across a coil that either heats or cools the air, as required.

Application of roofing insulation

P.523

Carpet ease of maintenance: staining resistance

Staining is a local discoloration of a carpet as compared with soiling, which is more or less uniform over the carpet surface.

Pozzolans

Varicose natural/artificial material that reacts with calcium hydroxide in wet concrete to form cementing compounds.

Water vapor permeance

is a measure of water vapor flow through a material of specific thickness or an assembly of several materials.

What building types would use the following voltage types? (A) 120/240v single-phase, (B) 120/280v three-phase, (C) 277/480v three-phase, (D) 2400/4160v three-phase

(A) Residences and small office buildings. (B) Small- to medium-sized commercial buildings because it allows for various electrical loads compared to 120/240v single-phase. (C) Large commercial buildings. (D) Very large commercial buildings and industrial buildings with a large amount of machinery.

Gypsum board fasteners

p. 671-672

Gypsum board adhesives

p. 672-673

Veneer: book matching

Any type of veneer can be book matches. In book matching, every other sheet is turned over like the leaves of a book. Thus, the back of one veneer meets the front of the adjacent joint design. Book matching is also called edge matching.

Shaft wall construction uses which of the following for connecting the panels?

C-H studs are designed to hold shaft liner panels, eliminating the need for finishing the joints with tape and compound.

Coaxial cable (coax)

Cable commonly used by cable operators, telephone companies, and internet providers to convey data, video, and voice communications.

Inverter

Commonly known as a power conversion system (PCS), an inverter is a device that changes direct-current (dc) to alternating-current (ac). An inverter is not the same as a power-conditioning unit (PCU).

Terrazzo application: strip placement

Divider or expansion strips should be used over beams and girders supporting the subfloor, because tensile stresses area likely to develop due to negative bending moments. Unbonded and bonded-underbed installations will usually have enough divider strips distributed over the floor so that expansion strips are not required except over expansion joints in the subfloor.

Low-E glazing

Double glazing with a thin film in the glazing cavity. Applied to the inside pane of glass in cold climates and outside glass in warm climates. Allows infrared to be transmitted and prevents loss of heat in the winter and excessive heat in the summer.

Application of walls shakes and shingles: single coursing

Each shake or shingle on walls should be nailed with a minimum of two nails, applied 2" above the buttline and 3/4" from the edge of each shingle or shake. On shginles wider than 8", two additional nails should be driven near the center and about 1" apart.

Wind exposure A, B, C, and D

Exposure A is for sites that are among tall buildings. Exposure B is for sites in residential-scaled neighborhoods. Exposure C is for sites surrounded by open fields. Exposure D is for sites next to open water.

Wall flashing - copings

Flashing should be carried beneath copings where the construction will not otherwise prevent water penetration.

Plumbing accessories

Floor drains, backwater valves, sewage sumps & ejector, interceptors

Frame components

Jamb extenders adapt windows to varying interior finish thickness. They are not usually a part of the window frame assembly but may be ordered loose as optional items. Interior trim is not usually supplied with stock windows. Typically it is selected separately and in some installations may be replaced by a gypsum board or plaster reveal.

Limiting the story drift on a structure in turn reduces which of the following?

Lateral sliding resistance is increased because the relative movement between adjacent floors is limited. The P-delta effect is the name given to the secondary forces in a structure that occur due to lateral displacement. In other words, when a building sways, it creates more load due to the displacement and distortion of the building.

LEED

Leadership in Energy & Environment Design

Properties of soil: others

Other soil characteristics that influence building foundations and slabs on grade are: - classification and composition - grain size - moisture content - density - capillarity - drainage characteristics - stratification - consistency - compressibility - climatic variations

Ohm's Law

The current I that will flow in a dc circuit is directly proportional to the voltage V and inversely proportional to the resistance R of the circuit. Expressed as an equation, this is the basic form of Ohm's law: I = V/R In ac circuits, the same relation holds true except that instead of dc resistance we use ac impedance. Ohm's law is frequently written in another form: V = IR which expresses the mathematical relationship that voltage is the product of current and resistance.

Properties of soil: internal friction

The internal friction of a soil can be described as the resistance of the soil grains to their tendency to slide over one another.

Sound loudness

The loudness of a sound depends on the intensity and frequency of the sound and on the characteristics of the human ear.

Diaphragm eccentricity and cutouts

This plan condition has a cutout in the floor plate that results in localized structural damage. The opening makes the diaphragm irregular and unbalanced.

Fan-powered VAV systems

This variation allows individual units to heat when the main supply system is cooling; it might therefore serve perimeter zones. In this case, the cool air is reduced to a minimum for IAQ, and the unit's fan draws additional air from a ceiling )or floor) plenum, heating it as required.

Aluminum siding installation

To prevent water entry and improve appearance, caulking should be used at junctions where siding abuts wood, brick, stone, or other metals. Caulking compounds should be durable synthetic materials compatible with the aluminum and paint finish.

Boards in wood

are pieces less than 2" thick and 2" or more wide. They include sheathing, subflooring, roofing, finish, trim, siding, and paneling. Boards less than 6" wide may be classified as strips.

Wet-pipe system

pipes contain water. This system type should be used in areas not subject to freezing, in lieu of a dry-pipe system, because it tends to deliver water to the fire a little faster than dry-pipe systems.

List five ways to aid in crime prevention through site design.

1. Provide adequate lighting along primary routes and touch points. 2. Try to minimize the number of entry points into a building. 3. Maintain sightlines. 4. Have clear wayfinding. 5. Think holistically.

Which of the following sources of heat delivers more energy than it uses?

A heat pump is used to move heat, not just convert energy to heat. A coefficient of performance (COP) is the ratio of the rate of heat delivered to the rate of energy input. Heat pumps have COPs that are greater than 1 and sometimes 2 or 3. Electric baseboard heat experiences a loss in efficiency. A boiler converts energy to heat with some loss in efficiency. A furnace converts energy to heat with some loss in efficiency.

Interlayment

A layer of felt or nonbituminous saturated felt not less than 18 inches (457 mm) wide, shingled between each course of a wood-shake roof covering.

Carpet durability: abrasion resistance

Abrasion resistance is the resistance of the fiber to wearing away due to foot traffic or other moving loads.

Framing Components

Stand C-member and channel members gauges are 20, 18, 16, 14, and 12.

Glass heat & chemical treatments: Tempering

Tempering is a heat treatment used to increase the strength of flat glass. The process involves heating the glass to just below the softening point and then chilling it suddenly by subjecting both surfaces to jets of cool air. This causes the surfaces to shrink and harden quickly while the interior is still fluid. The interior begins to col and shrink next, but since the surfaces are already hardened, they cannot flow and adjust to the shrinkage of the interior. This causes the surfaces and edges to be placed in a state of compression while the interior of the glass is in a state of tension. In properly tempered glass, the opposing stresses of the surface and the interior balance each other out. The resultant glass is much stronger than ordinary flat glass because the built-in compression of the surface must be overcome before breakage can occur.

Luminaire diffusers

a. Translucent diffusers b. Louvers and baffles c. Prismatic lens d. Fresnel lens

Volatile

they vaporize at room temperature

Siding applications p. 506-508

- Direct application method: first and odd-numbered courses, second and succeeding even-numbered courses - Shingle back method - Channel method - Wood nailing strip method

Weatherstripping types:

- Foam rubber - Felt stripping - Rolled vinyl - casement - Spring metal - Interlocking metal - Compressible bulb p. 603

Roll roofing - application

- Standard mineral-surfaced roll roofing - Double-coverage mineral-surfaced roll roofing

Glazed aluminum curtain walls - systems

- Stick systems - Unit systems: unit-and-mullion systems - Panel systems: column-cover-and-Spandrel systems p.584

Standards of quality for wood doors

- Wood flush doors p.576 - Wood stile-and-rail doors p.577

Exterior topcoat paints: aluminum paints

- general-purpose paints - heat-resistance paints p. 801

Vinyl composition tile (VCT)

Vinyl composition tile is composed of mineral fibers, ground limestone plasticizers, pigments, and polyvinyl chloride (PVC) resin binders. These resins permit light colors and a great variety of design. Some tile products are available with self-adhesive backs and "no-wax" surfaces.

Installation of formed-in-place metal roofing

Standing seams should be least 1" high. Flat seams are made by interlocking adjoining sheets. Flat seams are used in both directions in flat seam roofing and as cross seams in standing seam and batten seam roofing. Flat seam roofing may be laid with the seams parallel and perpendicular to the eaves or in a diamond-shaped pattern with the seams at a 45-degree angle with the eaves. In batten seam roofing, the battens may run up and down the roof from eaves to ridge or form ornamental patterns.

Electrical HVAC systems

System in which radiant heat is run through panels or wires into rooms and convection is used to heat spaces. It is the simplest system, with low initial costs, yet it has expensive life cycle costs.

Hardwood: birch

The heartwood of yellow birch and sweet birch is reddish-brown, with a slight variation in color among them. Similar slight variations also exist in the color of their sapwood, which is of a lighter shade than the heartwood.

Malleable cast iron

White cast iron may be made somewhat softer and more ductile, though not strictly malleable, by annealing (controlled heating and cooling). The carbon in the iron carbide is converted to a more dispersed graphite form, which provides greater ductility than does the flaky graphite of gray iron or the carbide of white iron.

Carpet yarn dyeing methods: stock dyeing

Wood and synthetic staple fibers can be dyed before being spun into yarn by dipping them in kettles of dye. This method ensures a uniform distribution of dye and is suitable where large quantities of a single-colored yarn are desired.

Preaction systems

are similar to dry pipe systems, except that the system is activated by a separate alarm that opens valves to allow water to fill the pipes before the heads open, thus permitting time for possible manual extinguishment before the heads release their water.

Mechanically formed joints

connections obtained by forming or cutting the parts to be jointed in such manner that they interlock

Plaster reinforcement installation

p. 649-650

Pitch

indicates the incline of a roof as a ratio of the vertical rise to twice the horizontal run. It is expressed as a fraction. Eg. Rise of a roof is 4" and the run is 12", the roof is designated as having a pitch of 1/6.

Window & door hardware

p. 603

Thick-crystal photovoltaics

The most common commercial type of PV material.

Electric strike

An electromagnetic door locking device created by a low-voltage current and used with various locksets. If the current is disrupted by a card reader or other trigger, the door is allowed to open. If the current is engaged, the door will remain locked.

Siding - backer board

An undercoursing material, typically fiberboard, used beneath siding materials such mineral-fiber-cement shingles. It adds insulation value, increases, resistance to impact, and provides a heavier shadowline at the butt than shingle siding applied directly without the use of a backing material.

Wall flashing - wall penetrating roofs

At chimneys and other walls passing through a roof, the base flashing should be capped with metal counter (cap) flashing that turns down over the base flashing and is anchored securely in the mortar joints.

Gypsum plaster types

Basecoat Plasters - Wood-fibered plaster - Bond plaster - Ready-mixed plaster Finish coat plasters - Gauging plaster - Gypsum Keens;s cement plaster - Prepared gypsum finish plaster - Veneer (thin-coat) plaster - Molding plaster - Acoustical plasters p. 654

Multizone systems

Because each zone has an individual centrally conditioned airstream, the total distribution tree volume grows to astonishing size with only a fe zones. The central station produces both warm and cool airstreams, which are mixed at the central location to suit each zone. These systems are more likely to be found on medium-sized buildings or on larger buildings in which smaller central stations are located on each floor. The single-return airstream collects air from all zones (as is the case for the other systems in this class). Energy savings result when a "bypass" deck is added, allowing each zone to choose some unthermally treated return air as part of the supply air.

Wrought steel products

Blackplate is the classification for cold-reduced products thinner than 0.0141" and wide than 12".

Burning and cooling of clay masonry units

Burning may be divided into six stages: the evaporation of free water (water-smoking), dehydration, oxidation, vitrification, flashing, and cooling.

Blast furnace slag

Byproduct of iron manufacturing that improves workability, increases strength, reduces permeability, reduces temperature rise during curing, and improves sulfate resistance.

Roof flashing

Flashings should be installed in roofs: - at eaves, rakes, and valleys of pitched roofs - where walls, pipes, curbs, and other elements penetrate - at roof drains p. 538

CMU compressive strength

Major influences on commpressive strength are: - type and gradation of aggregate - type and amount of cementitious material - degree of compaction attained in molding the units - moisture content and temperature of the units at the time of testing

Carpet durability: burn resistance

Most synthetic carpet fibers are flame-resistant to some degree, but they will melt and fuse when exposed to the heat of a burning cigarette or glowing ash which produce heat of more than 500 degrees F. Prolonged exposure to such concentrated heat may result in complete local loss of fiber or a slightly fused spot. The fused spot is more resistant to wear and abrasion than the surrounding area, and this causes a visible discoloration in the carpet surface. A carpet's flame spread during a full developed fire is measured by the Flooring Radiant Panel Test of ASTM E648. This flame spread index is called the critical radiant flux. It represents the minimum energy necessary to sustain flame. The higher the number, the more resistant the carpet to flame propagation.

Rubber tile

Natural or synthetic rubber is the basic ingredient of rubber flooring. Clay and fibrous talc or mineral fillers provide the desired degree of reinforcement; oils and resins are added as plasticizers and stiffening agents. Color is achieved by non-fading organic pigments. Chemicals are added to accelerate the curing process.

Roll roofing

Roll roofing requires the application of a continuous underlayment. This is usually No. 15 asphalt-impregnated, unperforated roofing felt applied with the long edge parallel with the eaves.

Properties of soil: cohension

The binding force that holds soil grains together is called cohesion.

Veneer: random matching

The joining of veneers with the intention of creating a casual unmatched effect is called random matching. In this type of matching, veneers from several logs may be used in the manufacture of a single panel. Random matching is generally used in prefinished V-grooved wall panels.

Sound wavelength

The length of a sound wave is calculated by diving the velocity of sound by the frequency: wavelength = velocity/frequency. Wavelength is the distance a sound travels during a single vibration. Since the velocity of sound is constant, each frequency has a different wavelength. To reflect a sound effectively, a reflecting surface must be equal to or greater than the wave length in size.

Mist systems

emit water in a fine mist that is less damaging to a building's contents than the streams emitted by other water-based systems.

Electroplating

employs an electric current and an electrolytic solution to deposit metallic coatings an steel or iron. Tin, zinc, cadmium, aluminum, and nickel are often deposited on steel, aluminum, and copper alloy by the electroplating process. Chromium and copper are similarly deposited on nickel that has been deposited on steel or aluminum. Chromium is also deposited over nickel that has been deposited over copper over steel. Electroplating is the chief method of making modern tin plate and the second most important process for making galvanized products. Lighter coatings of 0.10 oz/sf (for minimum corrosion resistance) and greater variations in coating thickness are possible by electroplating. The lighter coatings are normally recommended on surfaces to be painted or to be used in mildly corrosive exposures.

Relative humidity

may be measured directly or derived from DB and WB temperatures and is the ratio of the actual density of water vapor in air to the maximum density of water vapor that such air could contain, at the same temperature, if it were 100% saturated.

Building Materials Life Cycles

p. 38

Parging

should be applied in two coats. The first coat should be roughened when partially set, hardened for 24 hours, then moistened before the second coat is applied. Parging should be moist cured for at least 48 hours and dry before dampproofing is applied over it. In single-family residential buildings, parging is sometimes applied in only one 1/4" thick coat and it often applied in two 1/4" thick coats to a completed thickness of 1/2". In larger projects, two 3/8" thick coats are usually applied for a total thickness of 3/4". The latter method produces a better job and should be used even on small projects. A single 1/4" thick coat is much too thin to form a credible parging. Even 1/2" is too thin; the additional cost of the extra 1/4" of parging is small when compared with the benefits.

Typical footing size for residential resting on soil of average bearing capacity (2000 psf)

wall thickness = t width of the footing = twice the thickness of the wall = 2t depth of the footing = wall thickness = t

Private sanitary sewage disposal systems:soil absorption systems

- Absorption bed: similar to an absorption trench, except that it is more than 36" wide and contains two or more distribution lines. These are also called seepage beds. - Absorption field: an arrangement of absorption trenches through which treated sewage is absorbed into the soil. These are also called disposal fields and soil absorption fields. - Absorption trench: a trench not more than 36" in width, containing at least 12" of clean, coarse aggregate and a distribution line, through which treated sewage is allowed to seep into the soil. - Distribution line: an open-jointed or perforated pipe that permits effluent to escape into the soil for absorption. It may consist of 1' lengths of 4" agricultural drain tile or 2-3' lengths of vitrified clay sewer pipe (both laid with open joints) or perforated plastic pipe. Local experience and applicable codes and ordinances should be reviewed before selecting piping materials. - Seepage pit: a covered underground pit with a concrete or masonry lining. These pits are designed to permit partially treated sewage to seep into the surrounding soil. They are also called dry wells. Some jurisdictions do not permit the use of seepage pits. Only soils with a percolation rate of 30 minutes per inch or less are generally considered suitable for seepage pits; if the rate is greater than 60 minutes per inch, the soil is not suitable for any type of soil absorption system. There should be at least two laterals in every system. No lateral should be more than 100' long. Using more and shorter laterals is preferred because if something happens to disturb one line, most of the field will still be serviceable. The trench bottom and distribution lines should be level. Laterals should be spaced so as to provide at least 6' of undisturbed earth between trenches.

Polymer-modified bitumen membrane - application

- Cold application - Hot-mopped application - Torch and heat-weld application - Self-adhered application

Door weatherstripping types

- Foam rubber - Felt stripping - Rolled vinyl - Spring metal - Interlocking metal p.613

Heat-treated glass

- Fully tempered glass - Heat-strengthened glass p.627

Solid core doors

- Glued block core - Framed-block core - Stile-and-rail core - Particleboard core - Mineral-composition core - Wood-block, lined core

Elevator selection criteria

- Higher speed requirements dictate the use of gearless traction machines. Very tall buildings require very high speeds. - Generally, there should be one elevator for every 250 persons in a building of size or more floors. - People become annoyed when made to wait as little as 20 seconds in an office building but might be willing to wait for about a minute in an apartment building. - Double-deck elevators are sometimes used to increase capacity without reducing floor space. Similarly, in a sky=lobby system, express elevators take passengers to a level high in the building. There they leave the express elevator and take local elevators to their destination floors. These local elevators start at the sky-lobby floor, which leaves space between them open for rental use. Several levels may be used as sky lobbies. -For the same capacity and size, traction elevators tend to be heavier than hydraulic elevators.

Door hardware - locks

- Key-in-knob locks - Key-in-lever locks - Mortise locks - Interconnected locks - Auxiliary locks - Security locks - Padlocks p. 611-612

Composite glass

- Laminated glass - Insulating glass: spacer-edged, fused glass-edge p. 627-628

Planning guidelines for a neighborhood center

- One center serves as the focus - One mile between centers to isolate market demand for each center's retail and service uses - Mixed-use center core of 15-25 blocks - Core located at the intersection of neighborhood collectors, along one side of a major artery that serves as a boundary for the area - Center perimeter defined as 1/4 mile walking distance from core, or approximately 40-60 blocks in area - Area within perimeter outside the mixed-use center core provides a range of housing types and densities, approximately 3,000-4,000 residents

Gypsum lath types

- Plain lath: is ordinary gypsum lath consisting of a gypsum core and paper covering, with none of the special features incorporated in the other available types. - Perforated lath: before the development of Type X lath, perforated lath, with 3/4" holes drilled 4" on center in each direction, was used to improve the lath-to-plaster bond under fire exposure. The covering and core material are the same as for plain lath. - Foil-backed lath: to make foil-backed lath, a bright-finish aluminum foil is laminated to the back of plain lath. The foil acts as a vapor retarder and can act as a reflective insulation when the reflective surface faces a 3/4"-wide dead air space. - Fire-resistant (Type X) lath - special additives and glass fibers in the gypsum core of Type X lath improve its fire-resistant qualities. Covering materials are the same as for plain lath.

Five principal methods of cutting veneers are used:

- Rotary cut: to produce a rotary cut, a log is mounted centrally in a lathe and turned against a blade, producing exceptionally wide veneer compared to that cut by other methods. Since this cut follows the log's annular growth rings, the resulting pattern has a bold, variegated ripple figure. This is the type of cut used for most softwood veneers. - Flat slicing: flat slicing results in a variegated wavy figure. To produce it, a half-log, or flitch, is mounted with the heart side flat against the guide plate of a slicer, and the slicing is done parallel to a line through the center of the log. - Quarter slicing: quarter-sliced veneer has a series of stripes, straight in some woods, varied in others. To produce this type of cut, a quarter log (flitch) is mounted on a guide plate so that the growth rings of the log strike the knife at approximately right angles. - Half-round slicing: half-round sliced veneer shows modified characteristics of both rotary and plain-sliced veneers. It is a variation of rotary cutting in which segments of a log (flitches) are mounted off-center in a lathe. This results in a cut slightly across growth rings. - Rift-cut: various species of oak and some other species are sometimes cut using a rift cut. In these woods, the ray cells that radiate from the center of the log are conspicuous, and rift or comb grain effect can be obtained by cutting perpendicularly to these rays either on a lathe or on a slicer.

Carpet cushioning

- felted hair - rubberized fibers - sponge rubber: Rubber padding is more expensive, but it retains its resilience longer than hair padding. It is highly resistant to decay and mildew and is nonallergenic. It can be used at all grade levels, but the denser cushionings are not recommended for radiant-heated floors. - urethane foam

When compared with quarter-sawn lumber, plain-sawn lumber:

- is less expensive to produce because less labor and wasted are involved - shows some figure patterns involving growth rings and other figure sources more conspicuously - is subject to less shrinking and swelling in thickness - has round or oval knots that usually have a lesser weakening effect and affect surface appearance less than the spike knots that are more common in quarter-sawn lumber -has shakes and pitch pockets that extend through fewer pieces Conversely, quarter-sawn lumber: -is more costly to produce - displays some figure patterns peculiar to the radial surface more conspicuously - shrinks and swells less in width - tends to wear more evenly, because the radial surface is more uniform -holds paint better on radial surfaces in some species - works smoother for items run to patterns or profiles - twists and cups less and has less tendency to develop surface checks and splits in seasoning and in use

Interior primers: wall primers and primer-sealers

- latex - alkyd - oil - alkali-resistant p. 788

Exterior topcoat paints: exterior latex paints

- latex house and trim paints - semigloss maintenance finish - masonry paint - special latex paints p. 801

Exterior primers: masonry primers

- latex primers - alkyd primers - first coat of epoxy finish - clear sealer - silicone water repellents p. 799

Interior topcoat paints: flat finishes

- oil and oleoresinous flat paints - alkyd flat wall paints - latex flat wall paint - dry-fallout spray flat paints - latex floor paints p. 800

Roof underlayment performs several functions:

- protecting sheathing from moisture absorption until roofing is applied - providing important additional weather protection by preventing the entrance of wind-driven rain below the roofing onto the sheathing or into the structure - preventing direct contact between asphalt shingles and resinous areas in wood sheathing which because of chemical incompatibility, may damage the shingles. Underlayment should be asphalt-saturated felt or another material having a low vapor resistance. Laminated waterproof papers, coated felts, and other materials that act as vapor retarders should not be used. Such materials may permit moisture or frost to accumulate between the underlayment and the surface of the sheathing. Underlayment should be applied over the entire roof immediately after application of the roof sheathing. It should lap at least 2" at horizontal joints and 4" at end joints, and should be lapped 6" from both sides over hips and ridges. Only a sufficient number of fasteners need be used to hold the underlayment securely in place until roofing is applied. Roofing should not be applied over wet underlayment.

Exterior primers: metal primers

- red lead (read lead in oil) - red lead/mixed pigment - zinc chromate (zinc yellow) - zinc-dust/zinc-oxide - latex inhibitive primers - wash primers - portland cement paints p. 798-799

Hardwood: oak

- red oak - white oak - heartwood - sapwood Sapwood is limited only in clear grade, the top grade of flooring. Red oak flooring generally is higher in price and more uniform in color than white oak.

Interior topcoat paints: semigloss finishes

- semigloss wall paint - semigloss enamel - semigloss latex paint and enamel - dry-fallout spray semigloss p. 799-800

Transparent finishes

- stains: pigmented stains, dye-type stains, shingle stains - linseed oil - varnish - shellac - lacquer - polyrethane p. 802-803

Exterior topcoat paints: alkyd enamels

- trim enamels - equipment enamels - masonry enamels p. 801

Ballast types

-Magnetic -Hybrid -Electronic -Special 1. Low-current 2. High-current 3. Energy-saving 4. Multilevel

Items in a downfeed distribution system

-Water storage tanks -Two-story penthouse over elevator banks -Chimneys -Numerous plumbing vents -Exhaust fans -Air-conditioning cooling towers -Cantilevered rolling rig to support a scaffold for exterior window washing -Perimeter track for a window washing rig -Photovoltaic cells and/or solar collectors for DHW

Storm sewer systems

1. Building storm drain: A pipe that picks up water from interior sources and interior roof drains and carries it to a point 3' outside the building. 2. Building storm sewer: A pipe that picks up the water at the end of the building storm drain and carries it to a public storm sewer or disposal location on site. 3. Disposal point: A location where storm water is returned to the environment, such as a lake, stream, river, or ocean. 4. Drain: A pipe that carries water in a building's storm drainage system. 5. Site storm drain: A pipe that picks up the overflow from wells and springs, and storm water that falls on the site and is conveyed to it through curb inlets, site drains, manholes, and other structures, and carries that water to an outfall on site, a public storm sewer, or a disposal point. 6. Storm sewers: Pipes that carry collected storm water to a disposal point.

Heating methods:

1. Direct heating brings water in contact with directly heated surfaces: electric-resistance elements or other electrically warmed surfaces within tanks, or surfaces directly exposed to fire or hot gases. 2. Indirect heating can be accomplished in several ways. Coils containing steam or fluids can be submerged within water tanks or set within boilers, whose primary function usually is to provide space or industrial process heating. Alternatively, coils containing DHW can be placed outside a boiler but within a casing containing steam, hot exhaust gases, or very hot water. Direction and indirect methods can be utilized in a variety of equipment: Storage tank water heaters, the type most commonly used for residential and small commercial purposes. Circulating storage water heaters, in which the water is first heated by a coil, then circulated through a storage tank (as i some solar heaters). Tankless (instantaneous) heaters, in which the water is very quickly raised to the desired temperature within a heating coil and immediately sent to the point of usage.

What are the three types of cost periods in a life cycle cost analysis (LCCA)?

1. Length of study period: This period must be the same for all alternatives considered. It begins with a base date, to which all cash flows are discounted. It includes any planning, construction, implementation, service, and occupancy period. 2. Service period: Begins either when the building is occupied or when the system begins service. It is the period during which operational costs and benefits are evaluated. (Federal Energy Management Program [FEMP] projects limit this period to 40 years.) 3. Contract period: Begins when project team formally accepts the project and generally ends when the loan is paid off.

Fan-coil with supplementary air

A below-window unit that moves room air as it provides either heated or cooled air. Centrally conditioned, tempered fresh air is brought to the space in a constant-volume stream.

Concrete and masonry

A dash bond coat consists of a mixture of 1 part by volume of portland cement and 1 to 2 parts sand. A small straw broom or long-fibered stiff brush is dipped in the mix, and the material is splattered on the wall with a quick throwing motion. A dash coat should not be toweled an should be allowed to set before the plaster base coat is applied. If there is a delay in applying the base coat, the dash coat should be kept moist until the next coat is applied. A bonding agent is a proprietary waterproof chemical compound recommended by its manufacturer to exterior use to assist the bonding of plaster to concrete and masonry. Before a bonding agent is applied, the supporting surface should be structurally sounds and rid, as well as free from laitance, dust, grease, and materials that are soluble in water, such as water-based paints or glue.

Sanitary sewage disposal: DWV system components

A drain is any pipe that carries sewage in a building drainage system. Waste pipes carry water-diluted waste products; soil pipes carry the discharge of water closets, urinals, and other fixtures with similar functions to the building drain or building sewer. A trap is a fitting or device designed to provide, when properly vented, a liquid seal that will prevent the back passage of air without materially affecting the flow of sewage or wastewater through it. A vent system is a collection of pipes installed to provide a flow of air to or from a drainage system, or to provide circulation of air within such a system to protect trap seals from siphonage and back pressure. A building drain is the lowest part of a building's drainage system. It is the principal artery to which branches may be connected, and as such it is sometimes called the system's main. It receives the discharge from soil, waste, and other drainage pipes inside the walls of a building and conveys it through he foundation walls to a point 3-ft outside of the building, where it joins with the building sewer. The building sewer is the horizontal piping of a drainage system that extends from the end of a building drain to a public sewer, individual sewage disposal system, or other point of disposal. Soil stacks, or just stacks, are the central vertical pipes that are the collection points for the drain and vent lines in the DWV system. The portion of the soil stack that lies above the highest horizontal waste-carrying connection to it is called a stack vent; sometimes it is called a waste vent or soil vent. A horizontal pipe to which a number of vent stacks are connected before they go through the roof is also sometimes called a main vent. A stack vent or branch vent provides an air supply to equalize pressures and smooth the drainage process. The most desirable drainage pattern for water going down a vertical pipe is one in which water swirls down the pipe, clinging to the walls by surface tension.

Fly ash

A fine powder that is a waste product from coal-fired power plants. It increases concrete strength, decreases permeability, increases sulfate resistance, reduces temperature rise during curing, reduces mixing water requirements, and improves workability.

Direct current and alternating current

A flow of electric current that takes place at a constant time rate, practically unvarying and in the same direction around a circuit, is called a direct current. Whenever the flow of current is periodically varying in time and in direction, as indicated by the symmetrical positive and negative loops, or sine waves, it is called an alternately current (ac). The distance along the time axis spanned by a positive and a negative ac loop is called one cycle. The number of such cycles occurring in 1 second is known as the frequency of the ac current. Modern ac systems in the US and Canada operate at a frequency of 60 cycles per second, or 60 hertz (after Heinrich Herts). This means that current at 60 hertz is delivered to the consumer. In Europe and much of Asia, 50 hz is standard. Instead of resistance, the corresponding parameter in an circuit is impedance, which is (also) measure in ohms. Depending upon the circuit load, impedence can be markedly different from the dc resistance. For an ac circuit, Ohm's law is I = V/Z, where Z is the symbol for impedance.

Furnace vs. boiler system

A furnace is fired by gas or oil and used to heat air. A boiler heats water or some other fluid that is used to heat various heating systems. Both are about 80 percent efficient.

Induction system

A high velocity, high pressure, and constant volume of fresh air supply is brought to each terminal, typically located below a window, and forced through an opening, allowing the air within the room to be induced to join the new air. Very little centrally conditioned air is needed because the circulation is strong. To condition the air, it passes over finned tubes for heating or cooling. Thermostats control the unit's output by controlling the water or the air.

Chiller

A machine that removes heat from a liquid via a refrigeration cycle. In many commercial facilities that require air conditioning, chillers are a major energy user. Thus, it is important to select a chiller that costs as little as possible to operate for the specific application.

Draftstop

A material, device or construction installed to restrict the movement of air within open spaces of concealed areas of building components such as crawl spaces, floor/ceiling assemblies, roof/ceiling assemblies and attics. Draftstopping is required in the following locations • In floors to divide open concealed areas into no greater than 1,000 square feet areas . • In attics to divide open concealed areas into no greater than 3,000 square feet areas.

pH

A measure of the water's hydrogen ion concentration, as well as its relative acidity or alkalinity. A pH of 7 is neutral. Measurements below 7 indicate increasing acidity (and corrosiveness); water in its natural state can have a pH as low as 5.5, with 0 being the ultimate acidity. Measurements higher than 7 indicate increasing alkalinity. A pH as high as 9 can be found in water in its natural state, with 14 representing the ultimate alkalinity. The pH value is the starting point for determining treatments for corrosion control, chemical dosages, and disinfection.

Single-duct with reheat

A mechanical system where a central station provides a single stream of cold air that must be cold enough to meet the maximum cooling demand of any one zone in the system. All other zones reheat this air as needed (i.e., Zone A needs air that is 60°F and Zone B needs air that is 72°F; the 60° air will be delivered to ALL the spaces, and Zone B will use a reheat box to get the air to the desired 75°). This provides a smaller tree distribution because, in each zone, the only object added is a reheat coil that is small in size. In cold weather, the minimum outdoor air temperature has to be 38°F to be used. The colder this central airstream, the less air needs to be circulated. This system typically has a lot of waste unless carefully engineered for the right climate.

PV array

A mechanically integrated assembly of modules or panels with a support structure and other components, as required, including tracking apparatus where used, forming a power-producing unit.

Siding - single coursing

A method of applying shingles without an undercourse. In wood shingles, this method results in concealed nails and a smaller exposure than is found in double-coursed walls.

Thermosiphon

A method of passive heat exchange, based on natural convection, that circulates a fluid without the necessity of a mechanical pump. Thermosiphoning is used for circulation of liquids and volatile gases in heating and cooling applications such as heat pumps, water heaters, boilers, and furnaces.

Tile installation on walls

A mortar setting bed should be used on wall surfaces that are irregular, chipped, cracked, or coated with materials that would impede a bond. A mortar setting bed is installed over a base coat of mortar (scratch coat) applied to metal lath over a cleavage membrane. A scratch coat consists of 1 part portland cement, 5 parts damp sand, and 1/5 part hydrated lime. It is normally applied by a plastering contractor but can also be installed by the tile contractor. A float coat generally is applied by the tile contractor to ensure a plastic surface for setting the tile with neat cement.

Multizone systems

A multizone system is a collection of single-zone systems served by a single supply fan; such systems rarely exceed eight zones per air handling unit. Simultaneous heating of some zones and cooling of others is possible, but leakage between zones at the decks or hot and cold coils is common. Return air from all zones is mixed within one return duct; a bypass at the heating and cooling decks requires more space but allows such air to be mixed with supply without undergoing unnecessary heating or cooling. One multizone system per floor of medium-to high-rise buildings is an increasingly common application.

Water treatment: corrosiveness

A second major problem that can be treated is corrosiveness. A water supply can be rendered corrosive by high levels of dissolved carbon dioxide (yielding carbonic acid) or by low levels of calcium and magnesium carbonate (excessive softness). Symptoms of corrosion are staining of fixtures, reduced flow or pressure resulting from clogging, and leaky pipes. The stain are red if the supply piping is steel, green if it is copper. Clogging can occur due to either accumulated rust particles or to localized scaling triggered by the changes in pH that accompany corrosion. There are several solutions to corrosion problems. Mildly corrosive water from the natural supply can be treated with a neutralizing filter containing marble or limestone (calcite) chips. In severe cases, liquid sodium silicate and caustic soda can be added to raise the pH of the water. While this relieves the corrosion problem in most of a plumbing system, it does not sufficiently protect low-velocity areas such as storage tanks. Tanks with special protective coatings or sacrificial anodes should be considered.

Transparent finish

A system of materials used to form a protective film on wood that lets the wood color, grain, or both remain visible; applied either in the shop of factory or in the field; sometimes called clear wood finishes.

Composting toilets

Aerobic systems usually are essentially odor-free, and the exhaust air is rich in CO2 and water vapor. In contrast, anaerobic decomposition (ie. that which occurs without oxygen) is malodorous and produces methane gas as an important by-product. Ventilation is important, both to reduce odors and to facilitate evaporation of excess moisture. A ventilation stack is an essential feature; it is often assisted by a very small (3- to 5-W) fan. Problems with insect hatchings within the composting chamber can be lessened by keeping vegetable scraps out of the chamber, as the are frequent sources of insect eggs.

Air and water systems

Air and water systems are typically designed where the heating and cooling of each zone is accomplished with water running through the distribution tree. Because water holds more heat per volume than air, the distribution tree is thinner. For air changes, to control the quality of air in the space in regard to humidity and freshness, a centrally conditioned airstrip, equal to the total fresh air required, is provided. With this system, several distribution trees are typically required, but the space they need is typically less than that of an all-air system. Some air and water systems are induction systems, fan-coil with supplementary air, radiant panels with supplementary air, and water loop heat pumps.

Thermal classifications of materials: air films and air spaces

Air films and spaces are interesting thermal components. Although they are usually void of material, they have potentially useful thermal properties and contribute substantially to the insulating capabilities of some construction assemblies include at least two air films (interior and exterior), and many common assemblies include a substantial air space. At the exposed surfaces of solids, heat transfer takes place both by convection and by radiation. An air space is a planar volume of air contained on two sides by some elements (drywall, brick, insulation, etc.) of an envelope assembly. Like the air films discussed above, air spaces can contribute to the overall thermal resistance of a construction assemblies.

Door bottoms

Air leakage through cracks at door bottoms can be stopped with 1. sweeps attached to the door bottom, 2. weatherproof thresholds, or 3. door shoes. The most common types of sweeps consist of a felt or runner flap mounted in a metal channel. They seal most effectively on flat thresholds. They drag on carpets, however, and will eventually wear down from friction. To avoid carpet drag, automatic door sweeps can be used. These are spring-loaded and flip up when the door is opened, down when it is closed. An interlocking threshold consists of a metal sill that is shaped to interlock tightly with a metal channel attached to the door bottom. It is durable and provides an excellent weather seal but is difficult to install because proper alignment is critical. Weatherproof thresholds can be either vinyl-bulb or interlocking type. These threshold are difficult to install because a good fit requires that the door bottom be trimmed at or manufactured with a 1/8" bevel. A vinyl-bulb threshold contains a flexible vinyl strip which is compressed when the door closed. The threshold itself is metal and very durable, and although the vinyl bulb will wear out, it can be replaced. Door shoes are metal frames with attached vinyl bulbs that press against the threshold to form a tight seal. They are very durable because the bulbs can be replaced when worn. Doors hoes are best suited for flat threshold.

Hot water baseboard and radiator systems

Air vents and water drains are part of the distribution system. Except for the necessary air cushion in the upper part of the compression tank above the boiler, air must not be allowed to accumulate at high points in the piping or at the convector branches. Air vents at all high points relieve these possible air pockets that would otherwise make the system air-bound and inoperative. If a system is drained an d left idle in a cold house, water trapped in low points can freeze and burst the tubing or fittings. Operable drain valves must be provided at such locations and, of course, at the bottom of the boiler.

Paints

Air-drying materials; applied as a liquid in the field, except that primers are applied either in the field or in a shop or factory. The complete system of materials needed to produce a paint film is called a paint system. The tern paint includes primers, emulsions, enamels, opaque stains, sealers, fillers, and other applied materials used a prim, intermediate, or finish coats in a paint system. Paint is a mixture of minute solid particles known as pigment suspended in a liquid medium called the vehicle. The pigment provides hiding power and color. The vehicle combines 1. the solvent (thinner), which ensures the desired consistency for application by brush, roller, or spray, and 2. the binder, which bonds the pigment particles into a cohesive paint film during the drying process. Some paints dry and harden simply by evaporation of the solvent. Others involve chemical reactions as well as solvent evaporation. Most paints are described according to the type of binder used in them (alkyd, latex, oil, oleoresinous, rubber, urethane).

Glass heat & chemical treatments: Annealing of

All flat glass, after forming, is subjected to a controlled cooling process called annealing to relieve internal stress. If a piece of glass is not annealed, parts of it will cool and contract at different rates, and when the glass approaches room temperature, it may fracture due to differential stresses throughout the sheet. Annealing is performed by moving the glass on a belt through a continuous over called a lehr, in which temperatures are carefully regulated. The glass is first raised to a high enough temperature to relieve strain developed in the forming process. Then the temperature is brought down slowly so that all parts of the sheet cool at the same rate. Therefore, when the glass reaches room temperature, it is free of internal stress and can be easily cut and processed.

A multi-purpose clubhouse space is used for large dinners, presentations, plays, and other activities.The room is rectangular and is 65 feet by 45 feet. The ceiling is a flat drywall ceiling that is 16 feet high. There is a raised stage within an alcove at one end. The walls are drywall and the flooring is carpeting with a pad over concrete. There are several large windows with views.The client is reporting that there are sound issues in the space. Specifically, the client says that the room gets too loud, especially during dinners. The excessive noise in the room drowns out small group conversation. Performers also complain of sound reflections when presenting from the stage. What should the architect recommend for remediating the sound issues in this space?

All sound in a room is either absorbed, transmitted, or reflected. Two things need to happen in this room: overall noise level needs to be reduced and reverberation needs to be lessened. This means sound absorption must be increased and reflected sound must be decreased. The ceiling is the best location for the sound absorbing material because it is the closest surface to all the noise generation in the room besides the floor. There is also nothing to block the sound to the ceiling, like people or furniture, as sound travels up to the ceiling. We want as much direct sound to go from the performer to the audience. Putting sound absorbing material on the wall behind the performer absorbs the most delayed sounds that can muddy the acoustic experience. The sound absorbing material should be installed on the ceiling and the back wall behind the speaker. The other walls have large windows, anyway, so there isn't much wall surface to use for sound absorption. This room appears to have too many reflective surfaces, causing noises to reverberate and become muddy. Sound attenuation will help with sound transfer from one room to another. It cannot help with sound reflections and reverberation. A dome shape makes sound waves reflect along the dome, causing what is called creep.

PV system

All the components and subsystems that, in combination, convert solar energy into electrical energy suitable for connection to a load.

All-air systems

All-air systems are when air is the only transfer method used between the mechanical room and the areas served. The downfall of these types of systems is that air does not hold as much heat per volume as water, thus making the distribution tree large. A benefit is that all-air systems are the best systems for comfort; the air moving through the spaces are temperature and humidity controlled. Some all-air systems are single-zone systems; single-duct, variable air volume systems (VAV); fan-powered VAV systems; multi-zone systems; single-duct with reheat; and dual-duct, constant-volume systems.

All-water systems

All-water systems only heat and cool, and the distribution tree is very thin. Air quality is handled either locally, through an infiltration system or windows, or by fresh air from an adjacent system, such as a ventilated interior corridor zone. A fan-coil terminal is typically used so that air motion still occurs. Because air is handled locally, the system has very little cross-contamination of air from one zone to another. This system is easy to retrofit into an existing building but requires substantial maintenance; fan-coils need filters changed, and drip pans can cause problems. All-water systems include two - and four-pipe systems.

Electric power generation - AC

Alternating current is produce commercially by an ac generator, generally called an alternator. Its prime mover may be any type of engine or turbine. The process by which electricity is produced is based upon the fundamental discovery in 1831 by Michael Faraday of the principle of electromagnetic induction. Briefly, this principle states that when an electrical conductor is moved in a magnetic field, a voltage is induced in the conductor. If a conductor is formed into a coil and rotated in a magnetic field, a voltage of alternating polarity is produced, that is, alternating current. It does not matter whether the conductor or the magnet moves; the motion of the conductor and the field with respect to each other produces the voltage. It is only one step (that of development) from this rudimentary ac generator to the large, powerful alternator that produces ac in a modern power plant. The frequency of the voltage generated is a function of the machine design and the speed at which it is driven. Normal generator frequency in the US, as noted previously, is 60 hz, whereas in Europe and the Mideast it is 50 hz.

Tile: shower receptors

Although only the mortar bed method is recommended for shower receptors, the slope should be developed in the backing rather than in the mortar bed to ensure positive runoff of water that penetrates the tile finish. With a wood subfloor, a separate portland cement mortar fill should be used to create the slope. The fill can vary from 1/2" to 1-1/4" in thickness. It should include a latex additive to improve its bond strength and make it possible to apply it in thin layers. A waterproof membrane or pan should be installed over the sloped fill, followed by the tile finish set in a mortar bed.

Combining strategies: daylighting, cooling, and heating

Although the relationships between these three aspects of environmental control are quite complex, in general the decision to extensively daylight a building tends to decrease its need for electricity and cooling and increase its need for heating. This is due to the influence of the large glass areas associated with daylighting. In summer, properly shaded daylighting openings contribute less heat gain than the electric lights that the daylight is replacing. This reduces the need for both electricity and cooling. In winter, some solar gain through daylight openings assists with heating (especially with south-facing windows), but the daylight still replaces electric lights that would otherwise be additional sources of heat. Thus, compared to a conventional building of the same size and function, the daylit building is likely to use more heating energy (unless passive solar heating is emphasized), less electricity for lighting, and less cooling energy. Ventilation cooling strategies depend upon the air as a heat sink; evaporative/radiative cooling strategies depend upon both sky and air as heat sinks; earth coupling cooling strategies depend upon the earth as a heat sink.

Absorption of sound

Although the sound level goes down, no matter how much sound-absorbing material is introduced into the room, the level cannot drop below the level of the direct sound from the source to the listener. Sound-absorbing materials cannot "suck up" the sound from the source; they can only absorb what reaches them.

Cooling coils added to warm air furnaces

An air-to-air (in contrast to a water-to-water) refrigeration device: Air instead of water can be used to cool the condenser, and indoor air can be cooled directly by being passed over the evaporator coil in which the refrigerant is expanding from a liquid to a gas. Thus, heat is moved from the indoor air to the outdoor air by the step-up action or heat-pumping nature of the refrigeration cycle. When indoor air is cooled directly in this manner, by the expanding refrigerant, the process is usually known as direct expansion. The cooling coils therefore are often referred to as DX coils. Meanwhile, the compressor-condenser unit is placed outdoors on a concrete slab or on the roof. The unit creates a noisy, hot microclimate in summer - an influence on both site and building planning.

Multi-zoned system

An all-air mechanical system where each zone in a building has an individually centrally conditioned airstream. The central station for the overall building produces both warm and cold airstreams, which are mixed at a central location in each zone to meet the thermal needs of that specific zone. A single-return airstream collects air from all zones. This type of system is more likely to be found in medium to larger buildings, where each floor is a zone.

Alternative supply/return systems

An alternative approach with return is variously called air-exhaust window, an air curtain window, or a climate window. Developed is Scandinavia in the 1950s, this is a triple-glazed window that passes room air between a typical outer double-glazed window and an inner single pane. The inner pane thus is kept at very nearly the same temperature as the room air, which greatly increases comfort near windows on very cold (or very hot) days. Venetian blinds are often inserted in this cavity, where they can intercept direct sun and redirect its light toward the ceiling. The solar heat intercepted by the blind is carried off by the room air to a plenum above the ceiling, where such air to a plenum above the ceiling, where such air can be either exhausted or recirculated and its heat content either exhausted or recirculated and its heat content either reclaimed or rejected. The U-factor of these windows is dependent upon the rate of air flow between the glazing; typical flow rates are 4 to 6 cfm per foot of window width.

What system is required by elevator codes in case of fire?

An automatic fire recall (capture) system immediately returns elevator passenger cars to a predetermined floor (typically the ground floor) to remain parked, with the doors open, to allow firefighters to confirm that no persons are trapped in a passenger car.

Echoes

An echo is a reflection that can be heard as a distinct repetition of the original sound. Echoes are likely to occur in large rooms where there is an appreciable time lag between the original sound and the reflected sound. To be heard as an echo, the reflected sound must be heard at least 1/17th of a second later than the direct sound. Therefore, reflected sound must travel a path from source to listener at least 65-ft longer than the path of the direct sound. Echoes produced by concave surfaces because a curved surface by flat surfaces because a curved surface converges and focuses the reflected sound, increasing its intensity in the same manner that the curved reflector in a flash light focuses light. A ceiling having a center of curvature near the floor line is the most objectionable type of curved ceiling from the standpoint of focused echoes, since the focal point is brought closer to the audience than when the center of curvature is higher or lower. Focusing is best corrected by breaking up the curve or changing its shape. Treatment with acoustical materials is rarely enough.

Magnetic lock (mag-lock)

An electromagnetic door locking mechanism that is created by a current moving through a wire. If the current is disrupted, the metal wire is no longer magnetized and the lock will no longer function as a security method. It can be hooked up to fire alarms, card readers, or other trigger points to turn the current on or off and control the door.

Electromagnetic locks

An electromagnetic lock, magnetic lock, or mag-lock is a locking device that consists of an electromagnet and an armature plate. There are two main types of electric locking devices : fail-safe and fail-secure. A fail-secure locking device remains locked when power is lost. Fail-safe locking devices are unlocked when de-energized. Direct pull electromagnetic locks are inherently fail-safe.

Emergency panel in elevator

An emergency status panel may be provided and, especially in large buildings, in hospitals, and in some other building types, may be required by code, These panels contain the following items: - digital position indicator for each elevator within the group - controller indicator lights - controller key switches - emergency power indicator lights and key switches - fire service indicator lights - fire recall key switches - emergency telephone jack

Terrazzo isolation membrane

An isolation membrane is required in all unbonded installations to separate the underbed from the subfloor. The membrane may be 15 lb asphalt-roofing felt or 4 mil polyethylene film.

Roof insulation materials

Applying hot-applied, built-up roofing directly over polyisocyanutrate, polyurethane, and phenolic foam insulations sometimes leads to delamination and blistering problems. Therefore, the NRCA recommends that a layer or wood fiber, perlite, or glass fiber board insulation be placed over these plastic foam insulations when a hot-applied, built-up roofing system will be applied.

Wrought steel products - structural shapes

As many as 40 passes through grooved rolls may be required to produce a desired shape. The first sets of rolls drastically reduce the cross section and impart the approximate shape; the finishing rolls gradually form the final shape and, for deep sections such a s channels and angles, bend the legs into position.

Ceramic mosaic tile

Available types include: - unglazed peorcelain (frostproof) tile: made by firing refined ceramic materials; desnse, impervious, smooth, and highly stain- and wear-resistant; clear, luminous colors or granular blends; available with an abrasive surface in a few sizes and colors - glazed porcelain (frostproof) tile: made with the same body as unglazed porcelain tile; glazed with clear (transparent) glaze, ceramic glaze, textured glaze, metallic glaze, or special decorator glaze - unglazed natural clay (frostproof or nonfrostproof) tile: dense and abrasion-resistant; made from unwashed clays; rugged and slightly textured surface tough enough to minimize slipping; easily cleaned; also available with a slip-resistant face in 1 by 1 in sq only, in limited colors - glazed natural clay (frostproof or nonfrostproof) tile: same body as unglazed natural clay tile with a clear ceramic, metallic, or decorator glaze - Conductive tile: impervious; with additives that minimize electrostatic buildup and explosion hazard in rooms where explosive gas mixtures are used, such as hospital rooms and laboratories; tile and installation must comply with National Fire Protection Association (NFPABulletin No. 56A)

All-air systems

Because air is the only heat transfer medium used between the mechanical room (central station) and the zones it serves, and because air holds much less heat per unit volume than water, the distribution trees for this class are quite thick. Sometimes, to reduce duct sizes, higher velocities are used for supply air. This generates more noise and higher friction, resulting in more energy used by fans; higher velocity should be used only sparingly, where space limitations are extreme. For comfort, however, these systems are, overall, the best. The quantities of air moved through the central station(s) are heated or cooled, humidity-controlled, filtered, and freshened with outdoor air - all under controlled conditions. Within the zones, supply registers and return grilles allow a well-planned stream of conditioned air to thoroughly permeate all work areas.

What are the main soil types, and which are the best for bearing capacity?

Bedrock = 10,000 PSF Gravel/sand = 3,000 to 12,000 PSF Compacted sand/fill = 2,000 to 3,000 PSF Silt/clay = 1,000 to 4,000 PSF

Energy conservation equipment

Boiler flue economizers achieve heat transfer by passing the hot gases in a boiler's stack through a heat exchanger, thus preheating the incoming boiler water. Runaround coils can be used for heat transfer between intake and exhaust air ducts when these two airstreams are rather far apart. This circulating heat-transfer fluid usually contains antifreeze; it provides simple sensible heat transfer, with no restrictions on exhaust and intake location. No contamination of intake air by exhaust air is caused by this arrangement. The efficiency of such coils runs between 50% and 70%, and they are available in modular sizes up to 20,000 cfm. Economizer cycles use cool outdoor air, as available, to ease the burden on a refrigeration cycle as it cools the recirculated indoor air. The economizer cycle can thus be thought of as a central mechanical substitute for the open window; when it is cool enough (below the supply air temperature), 100% outside air can be provided and no chilled water is needed. When the outdoor air temperature is higher than the supply air temperature but lower than the return air temperature, outdoor air is reduced to that volume required for IAQ. Relative to open windows, this cycle has several advantages: energy-optimizing automatic thermal control, filtering of the fresh air, tempering of the cool outdoor air to avoid unpleasant drafts, and an orderly diffusion of fresh air throughout the buildings. Its disadvantages are the loss of personal control that windows offer and thus loss of awareness of exterior-interior interaction. In hot, humid climates, the moisture brought by 100% outdoor air may be unwelcome. Economizer cycles are available as options on most direct refrigerant machines (such as single-package rooftop units) and are typically installed for large-building central air supply systems. Buildings with high internal gains (internal load dominated) are particularly good targets for economizer cycles because they need cooling even when the outside temperature is chilly. Economizer cycles lend themselves readily to a cooling strategy of night ventilation of thermally massive structures because they have a built-in option for 100% outdoor air.

Hot water boilers

Boilers and their accessories comprise a wide inventory. A few selected types are discussed: 1. Oil-fired steel boiler. A refractory chamber receives the hot flame of the oil fire. Combustion continues within the chamber and the fire tubes. Smoke leaves through the breeching at the rear. Water, outside the chamber, receives the heat generated in the combustion chamber. If a domestic hot water coil is connected for use, a larger-capacity boiler is selected. An aquastat (water thermostat) turns on the burner whenever the boiler water cools off, thereby maintaining a reservoir of hot water ready for heating the building. 2. Gas-fired cast iron hot water boiler. Cast iron sections contain water that is heated by hot gases rising through these sections. Output is related to the number of sections. Additional heat is gained from a heat extractor in the flue. With induced draft combustion, condensing unit in the flue, and intermittent electronic ignition instead of a pilot light, up to 90% AFUE is attainable. The American Gas Association (AGA) sets standards for gas-fired equipment. 3. Oil-fired, cast iron hot water boiler. Primary and secondary air for combustion may be regulated at the burner unit. Flame enters the refractory chamber and continues around the outside of the water-filled cast iron sections.

Firestopping

Building materials or materials approved for use as fireblocking, installed to resist the free passage of flame to other areas of the building through concealed spaces. Fireblocking is required in the following locations: • In walls at the ceiling and floor level at horizontal intervals of 10 feet or less. • All interconnections between hidden vertical and horizontal spaces such as wall/soffits, walls/cove ceilings, wall/truss, wall, attic. • Stairways at top and bottom of the run • Ceilings and floor penetrations of ducts, pipes etc. • Exterior wall covering and furring.

Building sealants

Building sealants include: - elastomeric (rubber-like) sealants based on polysulfides, silicone, or polyurethane p.549-550 - solvent-release-curing sealants p.550 - latex emulsion sealants p.550 - tape sealants p.550 - acoustical sealants p.551 - performed foam sealants p.551 - oil-based caulking compounds p.551

Carpet tacked and tackless installation

Carpet that is not rubber-backed can be readily installed over nailable surfaces by tacking the edges or by using tackless strips around the perimeter. Tackless strips consist of pieces of plywood of the thickness of the padding with two or three rows of metal pins that pass through the plywood at an angle and are designed to grip carpet when it is stretched over the pins. Installations on concrete can be made b tacking if wooden plugs are provided 6-9" o.c. in the concrete slab to receive the tacks. Also, tackless strips can be installed on concrete with powder-actuated fasteners or epoxy adhesive. Two-row strips can be used when the carpet is 20' or less in width, but three-row strips should be used with wider carpet. Strips should be located at the entire perimeter of the carpet.

Alkalinity

Caused by bicarbonate, carbonate, or hydroxide components. Testing for these components of water's alkalinity is a key to determining which treatment to use.

Spray-applied fireproofing

Cementitious fireproofing materials include: - cement-mineral aggregate - mineral fiber - foamed magnesium oxychloride - magnesium cement

Induction

Centrally conditioned fresh air is supplied (at either high or medium pressures and velocities) to each induction terminal. Each terminal then mixes 20% to 40% incoming fresh air with the 80% to 60% room air that is induced to flow along with the fresh air, all passing over finned tubes for heating or cooling and circulating this mixture of air to the space. In two-pipe systems, either hot or cold water - not both - is available to temper this air mixture ordered by the thermostat linked to each terminal. Because cool air is distributed for most of the year, the two-pipe system is largely in heating mode (in colder climates). In four-pipe systems, the availability of both hot and chilled water makes it possible to switch instantly from heating to cooling for excellent thermal control. The induction terminal typically are located either below perimeter windows or above a suspended ceiling. Condensation from the cooling coil in summer and the need to clean the filters of the induced room air make under-window locations much easier to maintain, even if they intrude on the floor area available.

Class I, II, III standpipes

Class I Systems Class I Systems [2-1/2" (64mm) hose connections] are provided for use by fire departments and those trained in handling heavy water streams. In high rise buildings without sprinklers and beyond the reach of fire department ladders, Class I systems provide water supply for the primary means of fire fighting, i.e. manually. Class II Systems Class II Systems [1-1/2" (38mm) hose lines] are provided for use by trained building occupants until the fire department arrives. Class III Systems Class III Systems shall provide [1-1/2" (38mm)] hose stations to supply water for use by trained building occupants and [2-1/2" (64mm)] hose connections to supply a larger volume of water for use by fire departments and those trained in handling heavy water streams.

Sanitary sewage disposal: DWV system: cleanouts

Cleanouts are fittings that provide periodic access to the interior of drain pipes to permit removal of blockages of lint, hair, grease, and other solids. Cleanouts usually consist of a 45-degree Y-fitting of the same diameter as the drain pipe, with a removable screw-in plug. When the plug is removed, a cleaning tool can be inserted into the main drain line. A cleanout fitting should be located at the base of each soil stack and at the point where the building drain passes through the building's foundation. A cleanout should also be provided at each change of direction of more than 45 degrees, and every 50' in 4" pipe and every 100' in larger pipes, and their height and clearance should be adequate for inserting cleaning tool.

Paving joint sealants

Cold-applied sealants: cold-applied paving joint sealants include pourable elastomeric sealants complying with ASTM C920, which may be a jet-fuel-resistant sealant for concrete made with either urethane, coal-tar-modified polymer, or bitumen-modified urethane. Jet-fuel-resistant, coal-tar-modified polysulfide, and jet-fuel-resistant urethane sealants for concrete joints are also available. Cold-applied silicone paving joint sealants are also available, one for concrete-only joints and another for joints between concrete and asphalt. Hot-applied sealants: hot-applied elastomeric paving joints sealants are available for concrete-to-concrete and concrete-to-asphalt joints. Jet-fuel-resistant formulations are also available for concrete-to-concrete and concrete-to-tar-concrete.

Hydronic zoning

Comfort is one of warm air heating's advantages. The motion of air in the space helps to assure uniform conditions and reasonably equal temperatures in all parts of a building. The building can quickly be warmed with a forced-air system. It is possible to clean both the recirculated air and the outdoor air by means of filters and other special air-cleaning equipment. Air may be introduced to reduce odors and to make up the air exhausted by fans in kitchens, laundries, and bathrooms. Central cooling can be incorporated or introduced if ducts are designed originally to do so; cooling often calls for greater rates of air circulation. Humidification can be achieved by a humidifier in the air stream, and if cooling is included in the design, dehumidification can be accomplished in summer. For both heating and cooling, a common arrangement is to place the supply registers in the floor, below areas of glass. This is important for winter operation. With adequate attention to supply register placement, return grilles can be located so as to minimize return air ductwork. High return grilles pick up the warmer air for reheating at the equipment. In may systems, air circulates at all times and is warmed or cooled as required. Planning for warm air systems begins with the attempt to locate the furnace reasonably close to the center of the building. After the system is designed, a furnace must be selected. It should be capable of burning fuel at a rate suitable to make up the building's hourly heat loss. The rate of air delivery depends on the air temperature rise that is planned. Finally, the motor and blower must be powerful enough to overcome the friction of air against metal in both the supply and return duct systems, as well as the friction of air flowing through the furnace to adapt to the demands of the system and the building.

Design work in a historic district may require a special level of care, and an architect should note certain characteristics within the district to comply with the Secretary of Interior's standards for the treatment of historic properties. Which characteristics are essential to consider in the design of infill construction within a locally designated historic district? Select the three that apply.

Consistent building setbacks, particularly the buildings' relationship to the street, help to define the character of the district. These may or may not be harmonized with the underlying zoning regulations. Structural systems are not typically visible at the building exterior and are not subject to historic district review. Roof materials, including associated flashing materials, are character defining features, much like the materials employed on the facades. The placement of garages, parking areas, and driveways on the site is often reflective of how automobiles were integrated into the development during the historic district's period of significance. Placement of parking that is inconsistent with the historic district precedents could be considered to have an adverse impact on the district. Landscaping is typically not a consideration for the review of projects within historic districts; only permanent fixed features are usually considered as per the Secretary of Interior's Standards. While there may be a wide range of building materials employed in an historic district, there may be some materials that are either inconsistent or incompatible with the historic district's appearance. For example, a cedar shingle-clad building may not be suitable within the context of an older, established district where all of the buildings are masonry, but could be very appropriate in a beachfront community.

Control & expansion joints: joints in backing

Control joints are provided in cementitious materials such as concrete and stucco to localize shrinkage cracks due to loss of moisture by hydration and evaporation. When control joints are provided, expansion joints usually are not necessary because shrinkage exceeds the likely thermal expansion.

Gypsum board: cracking and ridging

Corner cracking may result from differential structural stresses at interior corners where adjacent walls or walls and ceilings meet. Joint ridging often results when joints are treated during cold or highly humid weather and occurs more frequently when joint compound us applied too thickly and is feathered over a wide area. These finish defects are not commonly encountered in multi-ply construction. In single-ply construction, cracking at interior angles can be minimized by corner floating; ridging can be substantially reduced by back blocking or strip reinforcing. A bullnose-edged wallboard may also be used to help overcome ridging problems in single-ply construction.

CLT

Cross laminated timber. An engineered wood building system of solid, prefabricated structural panels made from lumber that is stacked in alternating directions and bonded with adhesives. They are lightweight, structurally efficient, and gaining in popularity in the United States.

Warm air heating systems

Dampers are necessary to balance the system and adjust it to the desires of the occupants. Splitter dampers are used where branch ducts leave the larger trunk ducts. The flow of each riser can be controlled by an adjustable damper in the basement at the foot of the riser. Labels should indicate the rooms served. Some codes require dampers of fire-resistant material actuated by fusible links to prevent the possible spread of fire through a duct system. Turning vanes can be used to assist airflow at sharp turns in ductwork. Such assistance reduces friction within the ductwork, thus reducing the total static head against which the supply fan must work. Supply registers should be equipped with dampers, and their vanes should be arranged to disperse the air and to reduce its velocity as soon as possible after it enters the room. This is commonly done by providing vanes that divert the air, half to the right and half to the left. When a supply register is in the corner of a room, it is best if the vanes deflect all the air away from the corner. Return grilles are of the slotted type in walls and of the grid type in floors. All registers and grills should be made tight at the duct connection. Controls: The burner is started and stopped by a thermostat, which is usually placed in or near the living room at a thermally stable location that is protected from cold drafts, direct sunlight, and the warming effects of nearby warm air registers. A cut-in temperature of between 90 degrees and 95 degrees F is selected for the fan switch in the furnace bonnet. After the burner starts, the fan switch turns on the blower when the furnace air reaches the selected cut-in temperature. Burner and blower then continue to run while heat is needed. When the burner turns off, the blower continues to run until the temperature in the furnace drops to a level a little below the cut-in temperature of the fan switch. If, during operation, the temperature unexpectedly exceeds 200 degrees F, a high-limit switch turns off the burner in the interest of comfort and safety. As in all automatically fired heating units, a stack temperature control in the breeching cuts off the fuel if ignition fails.

Degree-day

Degree-day is a way of summarizing the heating (or cooling, in the case of cooling degree-days) requirements in a particular climate over the course of a year. It is used to calculate heating and cooling demand. Degree-days are defined against a base temperature, which is the approximate lowest outside temperature at which a building would not need heating in order to be comfortable. The difference between the base temperature and the mean ambient temperature for the day is a degree-day. For example, on a day in January in New York City, if the base temperature is 65 degrees F, and the average temperature for the day is 40 degrees F, there are 25 heating degree-days. If there is a whole month with 25-degree days, the month has 775 degree-days. The city of New York has 5,050 HDD annually.

Thermal properties of components: resistance

Designated as R, resistance indicates how effective any material is as an insulator. The reciprocal of conductivity (or conductance), R is measured in hours needed for 1 Btu to flow through 1 sf of a given thickness of a material when the temperature difference is 1 degree F. Resistance is especially useful when comparing insulating materials, because the greater the R-value, the more effective the insulator.

Underfloor supply with displacement ventilation

Displacement ventilation provides fresh air, cooled to just below the design room temperature, at a low velocity. Furthermore, fresh air supply rates are typically near 45 cfm compared to about 30 cfm often used in ceiling supply systems. This high-volume, low-Delta-t, low-velocity combination required greatly increased duct sizes, provided by using the plenum below a raised floor system. The fresh air rises quickly to the occupant level, drawn upward by the stack effect of heat gain from lights, people, and office equipment. It continues to the ceiling, where it stratifies and where various approaches to return air collection are located. Freshest and coolest at the floor, hottest and most stale at the ceilings, this system promises better IAQ and thermal comfort than would be available from ceiling supply - return systems. Furthermore, the outlets at the floor area adjustable and easily reached by the office workers.

Sound in doors and windows

Doors should be gasketed if sound privacy is required. Soft weatherstripping provides a good seal at the top and sides of a door, but automatic threshold closers area needed to seal the bottom. While it may be costly to use gasketed doors, the provision of a cushion such as sponge rubber between the door and its jamb will reduce the impact energy of a door slam and make door closure quieter. Unfortunately, properly sealed doors, because they are tight-fitting, are harder to close and more prone to warping. Operating single-glazed wood windows in grooved wooden tracks with weatherstripping, which are pressure sealed when closed, perform well. The performance of wood windows in metallic or plastic slides is fair against air infiltration but poor against resonant frequencies. Metal windows are available in many grades and quality levels. The better grades will perform acceptably if tight-fitting, properly sealed, correctly installed, and sufficiently rigid to reduce air infiltration and resonant vibration. Each glass pane should be mounted in a heavy frame and securely fastened in place. Using flexible or preextruded sealant improves the damping characteristics. Each glass pane should be of a different thickness or weight per square foot so that one can offset the deficiency of the other and they will not vibrate together or resonate.

Common building pollutants

Dust and pollen, tobacco smoke, mold and mildew, hazardous materials, perfume, VOCs, radon, sewer gas, formaldehyde, methane, pesticides, bird and rodent droppings, asbestos, lead, and carbon monoxide.

Sound wave motion

Each air particle vibrates only in the direction in which the wave is traveling, that is, along a straight line drawn between the particle and the source of the sound wave. The speed in a given medium is always the same, regardless of the pitch or loudness of the sound. We hear echoes because we hear the sound from the source and then a reflected sound, which has to travel farther, a few moments later. This same property of sound also causes the unpleasant reverberations we sometimes experience indoors.

Wood and decorative laminate casework quality standards

Economy grade is the minimum quality required for workmanship, materials, and installation and is typically reserved for woodwork that is not in public view, such as in mechanically rooms and utility areas. Custom grade casework is typically specified for and adequately covers most high-quality architectural woodwork. Premium grade is used in areas where the highest level of quality, materials, workmanship, and installation is required. Premium grade is the strongest and most durable of the three grades, but is usually the most expensive.

radiant panels with supplementary air

Either ceiling or wall panels contain the heated or cooled water to provide a large surface for radiant heat exchange. Centrally conditioned, tempered fresh air is brought to the space in a constant-volume stream. The "piece of equipment" within the space is replaced by a large surface, which must be kept clear of obstructions to radiant heat exchange.

Finish coats

Either trowel of float finishes may be obtained with gauging plaster, gypsum Keene's cement plaster, prepared gypsum finish plaster, or veneer (thin-coat) plaster. Acoustical plaster may be hand-applied but is usually machine-sprayed. Gypsum Keene's cement is used for gauging lime finish coat plaster, much the same as gauging plaster, but produces a harder, more moisture-resistant surface. Hardness is proportionate to the amount of gypsum Keene's cement. Both trowel and float finishes are possible with gypsum Keene's cement. Gypsum Keene's cement-lime-sand float plaster may be applied over all types of basecoat plasters but is particularly recommended over lightweight aggregate basecoat plasters. It provides greater crack resistance than a trowel finish.

Terrazzo resinous binders

Epoxy and polyester matrixes are two part formulations (a resin and a catalyst) to which a dry mix (fillers, pigment, additives, and decorative chips) is added. These resins are distinguished by good chemical resistance and adhesion, good abrasion resistance, and high impact strength. Epoxy matrixes also exhibit neglegible curing shrinkage. In addition to their high cost, they are toxic to the skin until cured.

Terrazzo application: underbed

Except at expansion strips, the adjacent sheets of this reinforcing should overlap by at least two mesh spaces. The surface over which the underbed is placed should be sufficiently wet to prevent water from being drawn out of the mix. Isolation membranes need only be uniformly dampened; concrete slabs should be thoroughly saturated by overnight soaking.

Decorative laminate cabinets

Face frames are made with mortise and tenon joints. Stretchers are needed at the top of base cabinets to support the countertop. Sides, dividers, tops, bottoms, shelves, and stretchers are covered on both sides with CLS HDLP. Backs generally have a thermoset decorative laminate on the surface that will be inside the cabinet. Backs are fastened to end panels and to top and bottom rails. Doors usually have a VGP plastic laminate finish on both sides. The thickness of doors for cabinets complying with the AWS varies, depending on the core type and the height and width of the door. Permissible core types are particleboard and plywood veneer. Drawer fronts, backs and bottoms should be rabbered into the sides and fastened with screws and glue. Some drawer units are molded plastic (except for the front), with rounded inside corners for ease of cleaning. Drawer fronts usually match the door fronts and are of the same construction. They should be positively fastened to a particleboard subfront with glue and fasteners. The subfront should be rabbered into the sides and fastened to them with mechanical fasteners and glue.

What heating and cooling system has a low life cycle cost (LCC) but a high initial cost?

Fan coil system. This system is very efficient for both heating and cooling but has a high initial cost because of the required amount of piping—it is a three- or four-pipe system.

Finishing in moderate-duty areas

Finish coats should be chosen from among the more washable flat and semigloss paints available. Glossier materials usually have better wear resistance and washability, but the accompanying higher surface shine makes surface irregularities more conspicuous, especially when natural or artificial light strikes the surface at a sharp angle. This consideration becomes less important in smaller spaces of where wall areas are broken up by interior furnishings.

Deluge sprinkler system

Fire sprinkler system in which sprinkler heads are always open. When activated by a sensor, all sprinkler heads activate at once. Used in high-hazard areas where flooding could be required to control a fire.

Application of roof shakes in new construction

First, a 36"-wide No. 30 asphalt-saturated felt starter strip should be laid along the eave line over the sheathing. The starter course of shakes at the eave line should be doubled, using an undercourse of 24, 18, or 15 in shakes, the last being made expressly for this purpose. Striking visual effects can be achieved by using a double undercourse at the eave line. After each course has been applied, an 18"-wide strip of No. 30 asphalt-saturated felt interlayment should be applied over the top portion of the shakes extending onto the sheathing. The bottom edge of the interlayment should be positioned at a distance above the butt equal to twice the exposure. Eg. If 24" shakes are being laid with a 10" exposure, the bottom edge of the felt should be positioned at a distance 20" above the shake butts; the strip will then cover the top 4" of the shakes and extend 14" onto the sheathing. Individual shakes should be spaced approximately 1/4 to 3/8" apart to allow for possible expansion due to moisture absorption. The joints between shakes should be offset at least 1.5" in adjacent courses. The joints in alternate courses also should be kept out of direct alignment when three-ply roof is being built.

Wall flashing - floor lines

Flashing should be used at floor lines where water entering a wall might be able to find its way into the building through floor edge construction. It should extend from the exterior face of the wall below the floor construction, up the exterior face of the floor construction, pass beneath the wall above, and turn up.

Wall flashing - expansion joints

Flashings are required at expansion joints in walls where water might enter the building. These flashings may be preformed of metal or plastic or may be formed in the field, usually from metal fashioned into a bellows.

Veneer: vertical butt and horizontal bookleaf matching

Flitches whose length does not permit its fabrication in the desired height of panel can be matched using the vertical butt and horizontal bookleaf method. In this type of matching, the veneer may be matched horizontally as well as vertically. This type of matching is often used in custom wall paneling and in furniture.

Wood floors

For basement construction, a 6 mil polyethylene film is applied over the gravel bed, and a concrete slab at least 3" thick is placed over the film. Placement of the film and the slab can be delayed until after the building is under roof. Backfill should not be placed against the foundation walls, however, until after the concrete slab is in place and set and the top of the wall is adequately braced. Where the height of backfill exceeds 4-ft, gravel should be used for the lower portion. For crawl space construction, a 6 mil polyethylene film ground cover should be used. Film edges should be lapped and sealed.

Water treatment: unpleasant appearance, odor, or taste

For example, yellow, cloudy water and rust-stained fixtures are frequently cause by suspended iron particles. In mild cases, these can be removed by an ion-exchange water softener, in more severe cases, an oxidizing filter containing manganese-treated sand is effective. Particles or organic matter, silt, or algae can degrade the appearance and taste of water. This problem can also cause pipe clogging and reduced water-heater efficiency. Such particles may be inherent in the water supply or may be introduced by backflow of drainage water into the supply system. If this water quality problem persists, fixtures should be checked for air gaps, and appliances such as clothes washers, laundry tubs, and dishwashers should be checked for vacuum breakers (backflow preventers). If the source is the water supply, a charcoal filter can be installed where the supply piping enters the building. In severe cases, a chemical feeder with a chlorine or alum solution can be used, followed by a sand filter. For small amounts of high-purity potable water, a reverse osmosis unit can be installed on individual fixtures. It features a membrane through which only pure water can pass. Rotten egg odor is caused by high levels of dissolved hydrogen sulfide can be anaerobic decomposition of organic matter somwhere in the supply chain. This occurs at many locations in the Southwest, Midwest, and Southeast. It can also be produced by magnesium anodes used to protect water heater tanks from corrosion. Water with dissolved hydrogen sulfide also has a black tinge and tarnishes silver. An oxidizing filter with manganese-treated sand can be used to alleviate this problem. Extreme cases call for chlorination followed by sand filtering.

Tile wood subfloor

For thickbed installations, either a single-layer subfloor of 1" nominal boards or 5/8" thick plywood are acceptable. For thin-set installations with most tile-setting products (except epoxy mortar), a double floor is required, consisting of a subfloor as described above and an underlayment. The underlayment should be exterior type CC-plugged plywood, 1/2" thick for residential use and 5/8" thick for commercial buildings. When epoxy mortar is used in residential construction, the underlayment can be omitted if a 5/8" thick plywood subfloor is used and the longitudinal joints between panels are supported with solid wood blocking 2x4 or larger members. A 1/4" space should be left between the underlayment and vertical surfaces, such as walls, and projections such as pipes or posts. For organic adhesives, 1/16" should be left between underlayment ends and edges. For epoxy mortar, 1/4" should be left at the ends and edges of panels, and these joints should be filled with epoxy. Adjacent underlayment edges should not be more than 1/32" above or below each other.

Warm air heating systems

Furnaces have become much more efficient in recent years, thanks to forced-draft chimneys and heat exchangers. Seasonal efficiencies of up to 95% are possible, in contrast to about 62% for older furnaces. The ADUE ratings for furnaces are based on an isolated combustion system that required that all combustion and dilution air be drawn from outside. Ducts are constructed of sheet metal or glass fiber and are either round or rectangular. Duct work will conduct noise unless these suggestions are followed: - Do not place the blower too close to a return grille. - Select quiet motors and cushioned mountings. - Do not permit connection or contact of conduits or water piping with the blower housing. - Use a flexible connection between bonnet and ductwork. Ducts also can be lined with sound-absorbing material to further discourage noise transfer, but beware of materials that encourage mold and mildew growth. Duct sizes may be selected on the basis of permissible air velocity in the duct.

Glass heat & chemical treatments: Chemical strengthening

Glass can be strengthened by chemical treatment as well as by heat treatment. The most commonly used chemical treatment involves an exchange of ions in the surface of the glass. The glass is immersed in a molten salt bath and the large potassium ions in the salt migrate into the glass surface, replacing the smaller sodium ions there. This action crowds the surface, resulting in compression stresses similar to those produced in glass by thermal tempering. Full temper in soda-lime glass is difficult to achieve by chemical tempering methods. A high degree of temper by chemical means generally requires accurate formulation of ingredients selected to ensure that glass ions interchange readily with ions in the molten salt bath. Furthermore, in chemically strengthened glass, the compressed surface layer is appreciably thinner than that in thermally tempered glass. Therefore, it is more readily weakened by surface abrasions such as cuts and scratches.

Wood shakes and shingles

Grade No. 1 (Blue Label) is the best or premium grade of shingle for roofs. These shingles are 100% edge grain, consist entirely of heartwood, and contain no knots. On 8 in 12 sloped roofs or steeper, Grade No. 1 shingles are estimated to heave a service life or more than 35 years under normal climatic conditions; on roof slopes of 6 in 12, a service life of at least 25 years can be anticipated; and 4 in 12 slopes, 20 years. Grade No. 2 (Red Label) is a good grade for roofs on secondary buildings and may be used on major building roofs when exposures are reduced about 20%. Shingles of this grade must be clear, or free from blemishes for 10, 11, and 15" for 16, 18, and 24" shingles, respectively. A maximum 1" width of sapwood is permissible in the first 10". Mixed edge and flat grain are allowed. Grade No. 3 (Black Label) is a utility grade to be used where economy is the prime consideration. It may be used for roofs of secondary buildings. These shingles may contain flat grain and sapwood, but must be 6" clear from the butt for 16 & 18" shingles and 10" clear for 24" shingles. Hip and ridge units are factory cut, mitered, and assembled to fit hips and ridges of various roof slopes. These units, which reduce costs by eliminating on-the-job trimming and fitting, are produced in either No. 1 or No. 2 grades in 16 & 18" lengths for a 6 in 12 roof slope, and are adjustable to fit any slope between 4 in 12 & 8 in 12.

Sources of loads within buildings

Gravity (the building itself, its contents, snow, ice, and water on the roof); wind, seismic, and hydraulic pressure (groundwater); soil pressure; thermal changes; shrinkage within building materials (similar to thermal changes); internal forces (for example, warping or loosening of the building components and settling); and vibrations (from machinery, for example).

Ground source heat pump

Ground-air heat pumps. also called geothermal heat pumps or Geo Exchange systems, are found in several configurations throughout North America. They often provide domestic hot water in addition to heating and cooling. An environmentally safe refrigerant is circulated through a loop installed underground (or in a pond of lake), taking heat from the soil in winter and discharging heat to the soil in summer. The loop is often high-density polyethylene (HDPE). Below the surface, soil temperatures are more stable year round than outdoor air temperatures, thus raising the COP relative to that of air-air heat pumps. The horizontal ground source closed loop heat pump requires trenches 3 to 6 ft deep; typically 400 to 650 ft of pipe are installed per ton of (12,000 btu/h) heating and cooling capacity. To squeeze more pipe length into a trench, a "slinky" coiled pipe is sometimes used. The trenches can be placed below parking lots or lawns and gardens. The vertical ground source closed loop heat pump is particularly applicable where the site area is limited. Vertical holes are bored from 150-450 ft deep. Each hole contains a single full-depth loop and is backfilled (or grouted) after the loop is installed. Because the temperature is must lower at greater depths, less pipe length is required than for horizontal loops. The distance between boreholes varies from a minimum of 15 ft with high water table and low building cooling loads to as much as 25 ft for buildings with high cooling loads. A minimum distance of 20 ft is usually recommended.

Piles for a new building's foundation must be used in a sensitive area adjacent to another building. Vibration and disturbance must be kept to a minimum. Which type of pile could be used? Check the two that apply.

H piles are driven into the ground, causing displacement and disturbance to the surrounding soil. Minipiles or micropiles are small high-strength piles. A small steel casing is drilled into the ground. Steel bars are then inserted into the casing and then grouted in place. The smaller size of minipiles makes them suitable for installations where minimizing impact is a main criterion. Helical piles screw into the soil like a nail screws into wood. This means there is no soil displacement, making them suitable for installations where minimizing impact is a main criterion. This type of pile is driven into the ground, causing displacement and disturbance to the surrounding soil. Precast concrete piles displace a lot of soil and are not a good choice when minimizing impact is a main criterion. Sheet piles are for excavations, not foundations.

Hardness

Hard water inhibits the cleaning action of soaps and detergents, and it deposits scale on the inside of hot water pipes and cooking utensils, thus wasting heating fuel and making utensils unusable. Hardness, which is caused by calcium and magnesium salts, can be classified as temporary (carbonate) or permanent (noncarbonate). Temporary hardness is largely removed when the water is heated - it forms the scale just described. Permanent hardness cannot be removed by simple heating.

Portland cement plaster mixes

Having too little water-cement paste in a mix causes poor workability, but adding either too much water or too much cement to improve workability results in a plaster that is subject to high drying shrinkage and cracking. Sand fines can contain a high percentage of clay particles which shrink excessively upon drying. An excess of coarse particles produces a harsh and difficult-to-apply mix. Therefore, aggregate should be selected carefully and mix proportions should not be relied on to overcome deficiencies in aggregate quality or gradation.

Water loop heat pumps

Heat pumps (water-air) either draw heat from the loop (heating mode) or discharge heat to it (cooling mode). For a large building in cold weather, the excess heat of the interior zones is thus used to warm the perimeter zones. The loop's temperature ranges between 65 and 90 degrees F; in hot weather, a central cooling tower disposes of the loop's excess heat, whereas in cold weather a central boiler adds the loop's needed heat. The loop is sized to carry 2 to 3 gpm per ton, where the total tonnage equals the sum of all the individual units (often greater than the actual load). Because individual heat pumps are used, this system is closely related to direct refrigerant systems; it is often considered an all-water systems.

Air-air heat pumps

Heat pumps have a high initial cost, and they have shown a relatively high frequency of compressor failure. Noise from the compressor and the outdoor air fan may affect site planning, especially for residences. One of the primary attractions of the heat pump is that in its heating mode it can give more energy than it receives (electrically), Although energy (usually electricity) is required to run the cycle, the pump draws "free" heat from a source such as outdoor air. The total heat delivered to the building is more than the heat (electricity) required to run the cycle. As outdoor temperatures approach 32 degrees F, the coefficient of performance drops and the outdoor coil tends to ice over. Built-in electric resistance coils must then be used; this of course, ends the efficiency advantage that made the heat pump attractive.

Hot water boilers

Heating capacity is the rate of useful heat output with the boiler operating under steady-state conditions, often expressed MBh (1000 Btu/h). This "useful heat" assumes that the boiler is within the heated envelope of the building: thus, the heat that escapes from the boiler walls is available to help heat the building. Select a boiler whose rating matches the calculated critical heat loss of the house or building; too small a boiler results in lower indoor temperatures at design conditions; too larger a boiler costs more and is a waste of space.

Finishing in heavy-duty areas

Heavy-duty areas are those in which there may be large amounts of moisture and grease in the air or where the amount and type of traffic requires a more durable paint film to withstand greater wear or more intensive cleaning. The usual choice is a gloss or semigloss enamel. Where the exposure is particularly severe, hard-gloss coatings can be used. The light reflectively factors discussed above for moderate-duty areas should always be considered when selecting gloss finishes.

Water temperatures

High temperatures -Allow the installation of smaller storage tanks (less hot water is mixed with cold water to achieve a final usage temperature at the shower, sink, or lavatory) but required larger heating units. -Can be achieved at the point of use (rather than in the tank) by heaters built into equipment such as dishwashers. -Can cause scale to form on heating coils and within piping (above 140 degress F in areas of hard water quality). -May be required by code for some applications but limited by code for others. -Limit the potential for growth of Legionella pneumophila bacteria (above 140 degrees F). Lower temperatures -Are less likely to cause burns but may not achieve desired sanitation. -Mean less energy consumed, because storage and pipe heat losses are lower. -Allow the installation of smaller heating units but require larger storage tanks. -Make possible the use of lower-grade heat sources for DHW, such as solar energy or waste heat recover. Around 13% of annual US energy usage is for DHW, which requires the lowest-grade heat source of all the common usages.

Hot water baseboard and radiator systems

Hot water heating circuits that serve baseboards or radiators come in four principal arrangements. In a series loop system, the water flows to and through each baseboard or fintube in turn. Obviously, the water at the end of the circuit is a little cooler, but because in all hot water systems the water temperature drop seldom exceeds 20 degrees F in residences, the average temperature can usually be used to select the baseboard or other elements. Valves at each heating element are not possible, because any valve would shut off the entire loop. Adjustment is by a damper at each baseboard, which reduces the natural convection of air over the fins. This is a one-zone system - all elements on, or off, together. There is no general rule about the maximum allowable length of a water circuit, but for long runs, the pipe size can be increased or several loops used in parallel to create more than one thermal zone. The one-pipe system is a very popular choice. Special fittings act to divert part of the flow into each baseboard. A valve may be used at each one to allow for reduced heat or for a complete shutoff to conserve energy - an advantage that the loop system does not provide. The one-pipe system uses a little more piping and thus is not as economical to install as the loop system, in which piping is minimal. Again, the supply water temperature will be lower at the end of the run than at the beginning. The two-pipe reverse-return provides the same supply water temperature to each baseboard or radiator, because it is not cooled either by passing through a previous baseboard or accepting the cooler return water. Equal friction, resulting in equal flow, is achieved through all baseboards by reversing the return instead of running it directly back to the boiler. This equality is effected by equal lengths of water flow through any baseboard together with its lengths of supply-and-return main. An air cushion tank, compression tank, or expansion tank is a closed tank containing air, usually located above the boiler. When the water in the system is heated, it expands, compressing the air trapped in the tank. This tank allows for the usual range of temperatures above the usual boiling point of water, without the frequent opening of the pressure relief valve. One type of air cushion tank, called a diaphragm tank, separates the air and water with an inert, flexible material; this prevents reabsorption of the air by the water.

Wrought steel products

Hot-rolled products intended for cold finishing are descaled (cleaned of surface oxide scale) usually by pickling, which involves passing the steel through sulfuric or hydronchloric acid, followed by rinsing with hot and cold water, steam drying, and usually oiling.

Elevator types

Hydraulic: Most appropriate for low-rise buildings, hydraulic elevators are usually slower and have a maximum travel distance of 50 to 60 feet. They use hydraulic pistons to push the elevator car from below. Traction (geared and gearless): Most appropriate for mid-rise and high-rise buildings, traction elevators use cables and counterweights to move the elevator car. The cable is attached to a motor at the top of the elevator shaft that moves the car up and down while using the counterweight to make the process more efficient. Machine room-less: Both hydraulic and traction elevators typically require a machine room to house the main motor, but recent advances in elevator technology allow both types to function without the requirement of a machine room.

Hot water baseboard and radiator systems

Hydronic and electrical controls allow automatic operation. There are two options for system control: 1. The thermostat controls the circulating pump and the boiler. In colder weather, the system operates almost continuously, and the average temperature in the system gradually rises. 2. The thermostat controls only the boiler, and the circulating pump operates continuously. This uses more energy for the pump but minimizes system temperature variation and thus the possibility of expansion noises. Makeup water is added as required, the air level in the tank is regulated by the air control fittings, and the circulator and burner operate as controlled by the aquastat and thermostat. If air vents in the piping are not automatic, they will require periodic manual "bleeding" of unwanted air. Circulating pumps are used to overcome the friction of flow in the piping and fittings and to deliver water at a rate sufficient to offset the hourly heat loss of the house or building. Pipe insulation is required whenever the pipes are outside the heated envelope of the building.

HVAC typical design processes:

I. Establishes design conditions. a. By activity, lists the range of acceptable air and surface temperatures, air motions, relative humidities, lighting levels, and background noise levels. b. Establishes the schedule of operations. II. Determines the HVAC zones, considering: a. Activities b. Schedule c. Orientation d. Internal heat gains III. Estimates the thermal loads on each zone: a. For worst winter conditions. b. For worst summer conditions. c. For the average condition or conditions that represent the great majority of the building's operating hours. d. Frequently, an estimate of annual energy consumption is made. IV. Selects the HVAC systems. Often, several systems will be used within one large building because orientation, activity, or scheduling differences may dictate different mechanical solutions. Especially common is one system for the all-interior zones of large buildings and another system for the perimeter zones. V. Identifies the HVAC components and their locations. a. Mechanical rooms. b. Distribution trees - vertical chases, horizontal runs. c. Typical in-space components, such as under-window fan-coil units, air grilles, and so on. VI. Sizes the components. VII. Lays out the system. At this stage, conflicts with other systems (structure, plumbing, fire safety, circulation, etc.) are most likely to become evident. Because insufficient vertical clearance is one of the most common building coordination problems with HVAC systems (especially all-air systems), the layouts must include sections as well as plans. Opportunities for integration with other systems also become more apparent at this stage; air ducts can also help distribute daylighting, act as sunshading devices, or fulfill other functions.

Heat-absorbing glass

If a metallic oxide is added to float glass during the manufacturing process, the glass can absorb significantly more sunlight, especially ultraviolet light. This characteristic distinguishes heat-absorbing glass from tinted glass that merely excludes the visible light useful for illumination (light-reducing). The sunlight absorbed by glass is reradiated and convected as heat to the inside or outside, depending on which side is cooler. The result is that in summer, more heat is dissipated to an air-conditioned interior because of its cooler temperature. In winter, more heat is dissipated to the outside because it is then cooler. However, the net effect is still beneficial because 17% less heat-producing sunlight is admitted through heat-absorbing glass than through clear glass. The performance of heat-absorbing glass is substantially improved when it is used as the outer sheet of an insulating unit. In an insulating unit, the absorbed heat must first bridge the air space to the inner sheet of glass before it can be radiated and convected into the building interior. Because heat transfer is slowed by the insulating air space, more heat is dissipated OT the outside air, which is in direct contact with the heat-absorbing glass. Furthermore, the outward rate of heat dissipation is greatly accelerated if there is wind.

Properties of soil: plasticity

If a soil is within some range of water content can be rolled into thin threads, it is called plastic. All clay minerals are plastic at some range of water content. Most very-fine-grained soils contain clay minerals and therefore are plastic. The degree of plasticity may be defined by the terms fat and lean. Lean clays are only slightly plastic, because they usually contain a large proportion of silt or sand. The plasticity index (PI) is a value expressing the numerical difference between the liquid limit and the plastic limit of the soil as determined by test, such as ASTM D4318. The PI is equal to the liquid limit (LL) less the plastic limit (PL): (PI=LL-PL). The LL is the amount of moisture present when the soil changes from a plastic to a liquid state. The PL is the amount of moisture present when the soil changes from semisolid to plastic.

Resilient flooring: alkali and grease resistance

If flooring is properly protected with a floor wax or finish and spilled oils or residues are removed promptly before they seep into the seams, such temporary exposure is not a hazard, except for materials with the lowest resistance ratings. Vinyl composition and solid vinyl tile are not affected substantially by either grease or alkali.

Sanitary sewage disposal: DWV system: gravity flow

In a water supply system, flow occurs because, the fluid is pressurized. Drainage system components exist at atmospheric pressure, and flow is due to gravity. Consequently, sanitary drain lines must be sloped and arranged to assist gravity flow. Connection of branch drains to main drains is always done in the upper half of the horizontal pipe. This reduces the chance of clogging, cuts down on interference with flow at the point of connection, and, when there is no flow in the branch, leaves the full diameter of the pipe available.

Sanitary sewage disposal: DWV system: drain piping - traps

In addition to waste, a drainage system contains air and foul-smelling sewer gases. For reasons of sanitation and comfort, it is desirable to prevent sewer gases from entering the building through fixture drains. To prevent this from happening, a trap is installed at each fixture. A trap is simply a length of drain pipe shaped in such a way that it does not drain completely. After each use of the fixture, a trap retains enough water to fill the drain pipe at that point. The trapped water serves as a seal that prevents sewer gas from rising through the fixture drain into the building. Each fixture requires its own trap. A drum trap is constructed so that the drain line from the bathtub enters its lower portion, and the drain line out into the rest of the drainage system leaves it 2-4" higher. Therefore, a water seal of 2-4" in diameter and have a removable top for easy access. A building trap is a device intended to prevent the circulation of air between the building drainage system and the building sewer.

Portland cement plaster mixes

In portland cement plaster to be applied by machine, the amount of water should be adjusted to produce a mix of proper consistency for the length of hose, temperature and humidity conditions, and type of plaster base. When measured with a standard 2 by 4 by 6 in cone, the slump should be from 2.5-4 in at the mixer and from 2-3.5 in at the nozzle. The hose length from the machine to the working surface should be as straight and short as possible.

First and succeeding courses - shingles

In the 6" method, the second course is installed with the first 6" removed. Each succeeding course through the sixth is started with a shingle having an additional 6" removed. Adjacent shingles are installed full width. The seventh course then starts with a full shingle, and the pattern described is followed again. In the 5" method, the second course is installed with 5" removed. Each succeeding course through the seventh is installed with additional 5" removed. Adjacent shingles are installed full width. Additional courses continue the 5" offset pattern. One method is to start the eighth course with 11" removed from the first shingle. In the 4" method, the second course is started with a shingle having 4" removed. Each succeeding course through the ninth is installed with an additional 4" removed. Adjacent shingles are installed full width. The 10th course then starts with a full shingle, and the pattern described is followed again.

Glass surface finishes: Silvering

In the early days of mirror manufacture, silvering was done by hand, the silvering solutions being poured from a pitcher onto the flat glass surface. Some fine mirrors are still produced this way today. Most mirrors, however, are manufactured by an automatic process in which the silver is deposited directly on the glass as it passes on a conveyor belt under sprays of silver nitrate and tin chloride. The silvering can then be protected with a coating of shellac, varnish, or paint. For almost permanent protection, an electroplated layer of copper can be applied on the silver.

Hot dipping

In the hot-dipping process the underlying metal is immersed in a molten bath of the coating metal. Zinc, aluminum, tin, and terne are applied to steel, for example, by the hot-dipping process. The most prevalent method is continuous hot-dip galvanizing, which accounts for more than 10 times as much galvanized steel as does the electrolytic process. The hot-dipping process, which results in heavier coatings than the electrolytic process, is the chief method of galvanizing tubular and flat-rolled products. Hot-dipped galvanized sheet and strip can be made with zinc coatings of designation G90 (0.90 oz/sf), which are used frequently in architectural applications. Heavier coatings of approximately 2 or/sf are made for severely corrosive applications. These coatings weights are the combined eights on both surfaces. Hot-dipped aluminized sheets are usually coated with an aluminum-silicon (5011&) coating known as type 1. Aluminum-silicon coatings provide excellent resistance to atmospheric and high-temperature (up to 1250 degrees F) corrosion and are extensively used in the automobile industry. In a process called zincating, aluminum plate is immersed in a zincate bath to coat it with a thin film of zinc. Zincating is general used to prepare aluminum for electroplating.

Unit of electric potential - the volt

In the ordinary dry cell, or in a storage battery, chemical action causes positive charges (+) to collect on the positive terminal and electrons [ie. negative charges (-)] to collect on the negative terminal. Assume for the moment that nothing is connected to the battery terminals. There is a tendency for flow between the electrified particles concentrated at the positive and negative terminals. Potential difference or voltage is the name given to this tendency, or force. The higher the voltage (pressure), the higher the current (flow) for a given resistance (friction).

Carbon steel door frame types

In welded frames, corners and intersections are fully welded or attached together using concealed welded splice plates. Corners should be mitered. Knockdown frames are made with mechanical joints. Most, but not all, have mitered corners. They are similar in design and appearance to welded frames, except that they are delivered to a project site disassembled for field assembly. Drywall slip-on frames are designed for installation in drywall partitions after the partitions are in place. Several designs are available. Storefront type frames are essentially welded frames. Frame sections that are too large to be shipped in once piece are shipped in several pieces and assembled in the field. Lead-lined frames are fabricated with lead linings or are of a modified design that will receive lead sheeting in the field. They are used in x-ray rooms and wherever else radiation is hazard.

Joint movement

Joints can be classified as either dynamic or static. Dynamic joints, which are also called movement joints or working joints, are joints that move with changes in temperature or other building movements. This includes all construction joints and some, but not all, separation joints. Dynamic joints in exterior walls are sealed to prevent air, water, and sounds passage through them. Dynamic joints in both interior and exterior horizontal and vertical surfaces are sealed to prevent light, air, water, sound, and vermin passage through them and to make them more aesthetically pleasing. Static joints have little or not movement. They are also called nonmovement joints or nonworking joints. They include such joints as those between interior door frames and adjacent masonry, plaster, or gypsum board. Static joints are usually sealed to prevent light, air, and sound passage through them and to provide a base for painting.

Conventional steel framing

Joints that are required to resist only shear are usually just bolted. Joints required to resist both moment and shear foces can be fastened using bolts alone, but such joints are both complicated and expensive. Therefore, joints resisting both shear and moment forces are either welded or, more frequently, both bolted and welded. Such joints are more expensive to produce than those designed to resist only shear forces. For this reason, an attempt is usually made, especially on larger buildings, to reduce the number of moment joints in a steel frame. Such a reduction in the number of moment joints in a building is often accomplished by making part of the frame rigid and tying the remainder of the frame to the rigid portions by means of rigid floor systems, such as steel decking with a concrete topping. Such a floor system must be designed structurally as diaphragms, meaning that it acts as a rigid unit to distribute horizontal forces acting on the building to the rigid portion of the frame, which is, in turn, capable of resisting those forces and transmitting them harmlessly to the ground.

Finishing in light-duty areas

Latex flat wall paints are usually preferred because of their easy application, quick drying, easy cleanup, and lack of odor. Alkyd flats can produce thicker films, have better hiding power, and give a more uniform appearance. These properties are particularly desirable on rough surfaces and when a considerable change is made in color. Both latex and alkyd paints have good resistance to soiling and marring and are relatively easy to clean. Odorless alkyd flats exhibit little solvent odor during application, but they must be used with adequate ventilation because the solvent fumes, while odorfree, may cause headaches and other physiological symptoms. The curing of these air-drying paints results in odors which can persist for several days, requiring continued ventilation.

Thermal properties of components: conductance

Many solids such as common brick, wood siding, batt or board insulation, gypsum board, and so on are widely available in standard thicknesses. For such common materials, it is useful to know the rate of heat flow for that standard thickness instead of the rate per inch. Conductance, designated as C, is the number of Btus per hour that flow through 1 sf of a given thickness of material when the temperature difference is 1 degree F. The units are Btu/h sf. Conductance is also used to describe the rate of heat flow through defined sizes of modular units of nonhomogeneous materials (such as a concrete masonry unit - composed of pockets of air surrounded by concrete).

Vinyl flooring underlayment

Mastic underlayment contains a chemical binder such as latex, asphalt, or polyvinyl acetate resins and portland, gypsum, or aluminous cement. Mixtures consisting of powdered cement and sand to which only water has been added function only as crack fillers and, when applied in thin coats, break down under traffic.

Thermal classifications of materials: conductors

Materials used as conductors are typically dense, durable, and diffuse heat readily. For a given material, the higher the numerical values of the three characteristics (density, conductivity, or conductance), the more successful that material's performance as a conductor.

Thermal classifications of materials: insulations

Materials used for insulation fall into three broad categories: 1, inorganic fibrous of cellular product (such as glass, rock wool, slag wool, perlite, or vermiculite), 2. organic fibrous or cellular products (such as cotton, synthetic fibers, cork, foamed rubber, or polystyrene), and 3. metallic or metalized organic reflective membranes (which must face an air space to be effective). Insulating materials are available in a wide variety of forms. Form-fitting materials include loose fill (as above a ceiling on the floor of an attic); insulating cement, a loose material mixed with a binder and troweled onto a surface; and formed-in-place materials such as expanded pellets or liquid-fiber mixtures that are poured, frothed, sprayed, or blown in place. Less form-fitting but more common are batts and blankets of flexible, semirigid insulation, with varying degrees of compressibility and adaptability to substrates. Rigid insulation, with little on-site adaptability, is applied in blocks, boards, or sheets and can be preformed to fit nonplanar surfaces such as pipes. Reflective materials are available in sheets and rolls of either single or multiple layers, sometimes as preformed shapes with integral air spaces. When used without attachment to blanket or batt insulation, a reflective layer is called a radiant barrier and is especially applicable to roofs in warmer climates. Radiant barriers are also useful in east- and west- facing walls in such climates; details of applications in the southern United States are found in Melody. A combination of dead (still) air spaces and reflective surfaces produces some of the most effective insulating products, especially when made of lightweight materials of low conductivity. Glass fiber, cellular glass, expanded styrenes (foamed plastics), and mineral fibers all enclose vast numbers of dead-air spaces per unit volume. When they are bonded to reflective films and properly installed (the shiny film facing a dead air space), high resistance to heat flow is achieved.

Permitted conditional or special uses

May be compatible with the district's permitted uses but are subject to discretionary review and supplemental standards intended to ensure that the particular proposed use is compatible with other uses permitted in the district.

Floor and ceiling systems in sound

Measures used to control structure-borne sound include 1. cushioning impact with soft floor-surfacing materials, 2. providing discontinuous construction by floating the finish flooring over the structural framing or subflooring, 3. providing discontinuous construction between the structural floor and the finished ceiling by mounting the ceiling on resilient devices or on separate ceiling joists, and 4. installing sound-absorbing insulation in the cavity of frame construction. Singly and in combination, these construction measures reduce impact sound transmission by breaking the direct structural connections that could carry vibration into other rooms and by absorbing some of the sound within cavities. Cushion-backed vinyl sheet flooring can be effective in controlling impact sound transmission when carpet is not desired, as might be the case in kitchen, laboratories, toilets, corridors, for example. Where an IIC of 51 or better is required, one of the following methods should be employed, depending on the degree of sound isolation required: 1. apply carpet and padding, either alone or in combination with a floated floor or separated ceiling; 2. use separated ceiling construction, by resiliently mounting either the ceiling material or using separate ceiling joists, in conjunction with a floated floor. The spaces between floor joists should be blocked where walls and floor and ceiling assemblies join to reduce airborne sound transmission through such flanking paths. Joints at the top and bottom of partitions should be sealed airtight with a resilient, nonhardening acoustical sealant or a resilient material.

Active solar heat gain

Mechanical equipment is used to collect/store solar energy, and it often requires a backup system. System examples include flat-plate collectors, concentrating collectors, evacuated tube collectors, and air-based systems.

Terrazzo metal reinforcement

Metal reinforcement is required in the underbed, except where the underbed is bonded ot a concrete subfloor, Underbed reinforcement should be corrosion-resistant welded wire fabric of at least 16-ga with wires spaced not more than 2" o.c. Thin underlayments for resinous toppings may used welded or woven wire weighing at least 1.4 lb/sq. yd. or expanded metal lath weighing at least 2.5 lb/sq. yd.

Fiber saturation point

Moisture in green wood is present in two forms: in the cell cavities as free water and within the cell fibers as absorbed water. When wood dries, its call fibers give off their absorbed water only after all the free after is gone and the adjacent cell cavities are empty. The point at which the fibers are still fully saturated but the cell cavities are empty is called the fiber saturation point. In most species, this occurs at about 30% moisture content. The significance of this condition is that is represents the point at which shrinkage begins. Even lumber cut with a green moisture content as high as 200% can dry to the fiber saturation point with no shrinkage of the wood. Only when the cell fibers begin to give off their absorbed water and start to constrict does the wood shrink. Therefore, all of the shrinkage wood can experience takes place between its fiber saturation point and a theoretical moisture content of 0% (over-dry condition). Within this range, shrinkage is proportional to moisture loss. Once wood has reached a 30% moisture content and below that level, for every 1% loss or gain in moisture content, it shrinks or swells, respectively, about 1/30 of the total expansion or contraction. For example, at 15% moisture content, wood will have experienced half of its total possible shrinkage. However, wood in service almost never reaches 1 0% moisture content because of the influence of water vapor in the surrounding atmosphere. Therefore, the total possible shrinkage is far less important than the probable shrinkage under ordinary conditions.

Membrane roofing system: substrates

Nailable substrates: nailable decks include wood planks, plywood, cement-wood fiber planks, lightweight insulating concrete, poured-in-place gypsum, precast gypsum planks, and OSB (oriented Strand Board). Nonnailable substrate: Nonnailable decks include poured-in-place concrete and precast or prestressed concrete and require an adhesion method for roof system installation. Insulated substrates: insulated decks are covered with one or more layers of insulating material. The underlying deck may be nailable, metal, or concrete. Insulation may be boards, sprayed-in-place plastic foams, or a thermosetting insulating fill. Steel decks are covered with a layer of insulation (usually boards), even when the insulation is not necessary for thermal purposes, because membrane roofing materials are not designed to span the flutes in steel decking.

Application of wood and hardboard siding

Nails should be located high enough to miss the coarse below by at least 1/8" to permit movement in the boards. Boards up to 6" wide can be blind-nailed through the base of each tongue with one nail into each stud. Wider boards should be face-nailed with two nails into each stud. Nails should be long enough to penetrate at least 1.5" into the studs. A 1/8" gap should be left at the top of each tongue to provide for expansion. Boards should be face-nailed into each stud, with one nail in boards up to 6" wide and two nails in wider boards. Outside and inside corners should be flashed with a 12" wide strip of underlay material centered in or around the corner or with metal flashing when corner boars are used.

Masonry non-load-bearing walls

Non-load-bearing walls on the exterior may be 4" less in thickness than is required for bearing walls but not less than 8" in thickness except where 6" thick walls are permitted to one-story residence.

Subdrainage systems

Nonperforated pipes are laid with open joints. These joints are then covered with a layer of screening to prevent fine particles from the fill above the pipes from entering the pipes through the joints. This screening material is usually heavy mesh burlap, coal tar-saturated felt, copper mesh screen, or synthetic filler fabric. Perforated pipes are laid with the perforations facing down and the joints closed in accordance with the pipe manufacturer's instruction. Drainage fill material is gravel or crushed stone evenly graded so that all of it passes a 1.5" sieve and not more than 5% passes a No. 50 sieve. Foundation drains are placed in a bed of compacted drainage fill material around the exterior perimeter of a building's foundations. Drain pipe should be placed far enough below the floor slab to properly drain and with its lowest invert (bottom of the pipe) at least 4" above the bottom of the footing to prevent possible washout of the soil beneath the footing. Footings should be lowered if necessary to meet these parameters. Underslab drains are placed in trenches filled with drainage fill material. Pipes are usually placed in parallel rows across the building. Depending on the distances involved, interceptor pipes may be placed perpendicular to these rows to reduce the depth of the piping required to establish a positive drainage slope. In traditional installations, foundation drain pipes are set in a compacted 4"-thick bed of drainage fill material laid with its bottom on the undisturbed subgrade at the bottom of the footing. The pipes are then covered with drainage fill material that extends from 4-6" on each side of the pipe up to a level about 12" below the surface of the ground. The drainage fill should be placed in 3"-thick layers, and each layer should be compacted before the next layer is placed. The drainage fill material is then covered with a layer of No. 15 asphalt- or tar-saturated felt or filter fabric to prevent fine materials form infiltrating the drainage fill. An impervious fill material (earth) is then applied to bring the grade to that required, with care taken to slope it away from the building. Another method is being used today in some installations to overcome the difficulty in a traditional installation of keeping the drainage fill material and adjacent backfill materials separated. The preceding discussion about the traditional method applies to this method as well, except that the drainage fill material is stopped 4-6" above the drain pipe and an in-plane drain is placed against the foundation wall from the bottom of the drainage fill to a level about 12" below grade. In-plane drains (also called drainage boards) are thin boards (usually about 1" consisting of two parts. The drain portion is made of a plastic material configured so that it forms multiple open pathways that permit water to flow freely through them. This side facing the earth is a layer of synthetic filter fabric that permits water to enter the drain but excludes fine soil. These boards can be installed using adhesives or mechanical fasteners as directed by the manufacturer.

Cast-iron boilers

Often used in residential and light-commercial applications, these are lower-pressure and lower-efficiency boilers. They do have the advantage of being, modular. In addition to the boilers themselves, there are choices of burner types (depending on the fuel(s) used, burner controls, and boiler feedwater systems. Fossil fuel-burning boilers need flues for exhaust gases, fresh air for combustion, and required air pollution control equipment. The exhaust gas is usually first taken horizontally from the boiler; this horizontal enclosure, or flue, is called the breeching. The vertical flue section is called the stack. As a general rule, combustion air can be supplied in a duct to the boiler at an average velocity of 1000 fpm. The duct should be large enough to carry at least 2 cfm per boiler horsepower. Furthermore, ventilation air to the boiler room should be provided; preferably, the inlet and outlet should be on opposite side of the room.

Sound frequency

One complete round trip of a vibrating body, starting from its neutral position, moving to one side, then to the other side, and back to neutral, is called a cycle. The number of cycles performed in 1 second is called frequency. Frequency, then, is measured in cycles per second (cps) and may be expressed as hertz (hz) (1 cps). Each air particle in a sound wave has the same frequency as the source. The performance and efficiency of acoustical materials in absorbing sound and the ability of materials to transmit sound vary, depending on the frequency of the sound.

Measuring sound absorption

One unit of absorption (called a Sabin) is equal to 1 s.f. of totally absorbent surface. An open window 1 s.f. in area is equivalent to 1 sound-absorbing unit, because, theoretically, all sound that strikes it passes through; none is reflected. Therefore, an open window has 100% absorption. An absorption coefficient (a) is assigned to materials to measure the percentage of incident sound energy absorbed by them. These vary theoretically from 0 to 1. A perfectly reflective material has an a = 0, and a perfectly absorptive material has an a = 1. A material with an absorption coefficients vary with the frequency of the sound, it is necessary to test materials at more than one frequency in order to cover the complete range of sound frequencies.

Valley flashing for wood shakes

Open valleys are first covered with a No. 30 asphalt-saturated felt underlayment strip, at least 20" wide, centered in the valley and secured with enough nails to hold it in place. Metal flashing strips, 20" wide, are then nailed over the valley underlayment. If galvanized steel flashing is used, it should be 18-ga, preferably center-crimped, and painted on both surfaces. Valley sheets should be edge-crimped by turning the edges up and back approximately 1/2" toward the valley centerline. This provides an additional waterstop, directing water down the valley. Shakes laid to finish at the valley should be trimmed parallel with the valley to form a 6" wide gutter. Closed valleys should first be covered with a 1x6 wood strip, nailed flat into the saddle and covered with roofing felt, as discussed above for open valleys. Shakes in each course should be edge-trimmed to fit into the valley, then laid across the valley with a metal flashing undercourse having 2" headlap and extending 10" under the shakes on each side of the saddle.

Superplasticizer

Organic compounds that transform a stiff concrete mix into one that flows freely into forms; used to help place concrete in challenging circumstances or to reduce the water content in a mix in order to increase its strength.

Dry-pipe system

Pipes contain air. The loss of air pressure from the opening of a sprinkler head of the detection of a fire condition causes the release of water into the piping system and out of the opened nozzle. Dry-pipe systems are used in areas subject to freezing and in other areas where leaks would cause severe damage.

Water supply pipe material: plastic

Plastic is much less thermally conductive than metal pipe. Therefore, it is a better insulator, which reduces heat loss from hot water lines and condensation on cold water lines. PVC is most frequently used for cold water supply lines. It can be used for the entire cold water supply system within a building. Joints in PVC pipe can be either solvent-welded or made with threaded fittings, which are commonly available in heavier weights of pipe. PVC pipe is manufactured in two types. Type I is unplasticized and has maximum working temperature of 150 degrees F. Type II is plasticized by the addition of rubber, which makes it less brittle than Type I. In addition to water lines, PVC pipe is used for natural gas and electrical conduit lines. PE pipe is used for cold water supply from a municipal water main or well to a building. It has lower range of working temperature than most other plastics: from -67 degrees F to 122 degrees. PE pipe comes in Types I, II, and III, in order of increasing density. Joints in PE pipe are made with tapered serrated inserts of polystyrene or galvanized steel that slip into the end of the PE pipe. The pipe is then compressed against the insert by means of a metal hose clamp. CPVC is more costly than PVC pipe and is, therefore, generally restricted to hot water supply lines, where it is the most prevalent type of plastic pipe. It can be used with water temperatures up to 212 degrees F, although the water heater relief valve in a system using CPVC pipe should be set no higher than 180 degrees F. Support clamps should be provided on horizontal runs every 3' to prevent sagging. The use of CPVC pipe is usually restricted to hot water lines. Joints are solvent welded. PEX is suitable for either cold or hot water pipes. It can be used either below or above ground but is not suitable for exterior exposed locations. It is flexible. PEX is installed using mechanical fittings or compression fittings. It cannot be jointed with solvent cement, glues or heat fusion.

Portland cement plaster

Portland cement plaster is used in both interior and exterior locations where it will be exposed to direct wetting or high moisture. In much of the country, exterior portland cement plaster is called stucco, while interior portlant cement plaster is called simply plaster. In some regions, however, especially along the West Coast, both interior and exterior portland cement plaster is referred to as stucco. Portland cement plaster is also used as a parging coat over masonry. Parging is often applied below ground to increase a wall's resistance to moisture penetration and to serve a base and leveling coat to receive dampproofing and waterproofing. The ingredients of portland cement plaster are essentially the same as those of concrete and of portland cement mortar. These include cementitious materials, which act as a binder, aggregate, which acts as an inert filler and provides strength; water, which, together with the cementitious materials, forms a paste and initiates the reaction that binds the aggregates together into a solid mass; and admixtures, which improve the plasticity or cohesiveness of the mix or retard or accelerates the setting time.

Portland cement crack control

Proper design of supporting construction, selection of materials, and application of portland cement plaster will minimize cracking. Cracks develop in plaster from 1. shrinkage stresses, 2. structural movement, 3. weak sections in the finish due to thin spots, openings, or changes in materials in the supporting construction, or 4. restraints due to penetration of mechanical or electrical equipment or intersecting walls or ceilings. p.665-666 Excessive water in a mix increases the volume of minute voids in the plaster as water evaporates or is used up in hydration, which results in higher shrinkage and lower strength.

As people age, what physiological effects can make it harder for them to interact with their environments?

Pupils narrow and lenses get thicker and cloudier, making it harder to see and requiring more light than younger people to see the same thing. Older people are also more sensitive to intense light and glare. Hearing loss, usually within a certain range of tones, occurs over time so that people don't always notice it. Loss of elasticity in some tissues, making it harder to breathe and reducing oxygen in the blood supply. Loss of muscle mass, leading to loss of dexterity and flexibility. Loss of nerve cells, reducing the amount of information that can be processed, slowing response time, and inhibiting coordination. Memory loss.

Veneer: slip matching

Quarter-sliced veneers are often slip matched, but this method may also be used for other types of veneer cuts. In this type of match, adjacent sheets are joined side by side, without turning, to repeat the flitch figure. Slip-matched veneers are common in premium, good, and specialty hardwood plywood grades and are often used in doors and matched, ungrooved wall panels.

Thermal properties of components: emittance

Radiation heat transfer is highly influenced by surface characteristics; shiny materials are much less able to radiate than common rough building materials. This characteristic is called emittance, the ratio of the radiation emitted by a given material to that emitted by a blackbody at the same temperature. For most materials, emittance is related to absorptance: a highly absorptive (low-reflectance) material will usually have a high emittance as well. Selective surfaces (sometimes used in solar collectors) are highly absorptive yet have very low emittance.

Resilient flooring selection criteria

Resilience is related to quietness, indentation resistance, and underfoot comfort. These and other properties may be combined into ratings for durability and ease of maintenance. Moisture and alkali resistance must be considered together in determining a suitable location with respect to whether the flooring is suspended, on grade, or below grade.

Restrictive, affirmative, and conditional covenants

Restrictive covenant: a type of deed restriction that implies limitations or stipulations to particular aesthetics or uses; often used in residential areas to control fencing type/color, boat storage, etc. Affirmative covenant: a type of deed restriction that promises a responsibility or future action, such as paying HOA fees or holding adequate levels of insurance. Conditional covenant: a type of deed restriction that, if broken, means the land will revert back to the original owner stated. Note that all covenants are binding and enforceable.

Metal fasteners

Screws are often used in roof specialties, nails in flashings. Fasteners should extend not less than 1.5" into solid, pressure-preservative-treated wood.

Veneer: four-way center and butt matching

Several special matching effects are used in furniture manufacture and in custom wall paneling. One of these, four-way center and butt matching, is ordinarily applied to crotch or stump veneers to reveal the figure. Occasionally, flat-sliced veneers are matched in this manner when panel length requirements exceed the length of available veneers.

Frame assembly of aluminum windows - welding

Several welding methods are used. Flash (butt) welding produces a continuous weld across the entire across section of a shape. It is made by forcing two members together at their intersection under pressure and applying a voltage that melts the parent metal. Flashing welding uses no filler material of flux and forms a rigid, strong, neat, watertight joint. Inert gas welding uses filler material and is similar to conventional gas welding used on other metals. It is seldom continuous and is generally used to join members that are of dissimilar shape. Inert-gas-welded joints can be made reasonably watertight, but a mastic sealing material may be required at the lower corners to prevent water leakage.

Shakes in wood

Shakes do reduce the shear resistance of wood used for beams, however, so limitations are imposed during grading.

Preparation for roof - wood shingles

Shingle exposure should not be larger than the length of the shingle minus 1" divided by 3. This will provide at least triple coverage (three layers of wood at every point) to ensure complete freedom from leakage in heavy wind-driven rain or snow storms.

Wall flashing - wall openings

Sills: sill flashing should be placed under and behind every sill. The ends of sill flashing should extend beyond the sides of an opening and turn up at least 1" into the wall. Sills should slope and project from the wall to drain water away from the building and to prevent staining. When the undersides of sills do not slope, a drip notch should be provided or the flashing may be extended and bent down to form a drip. Heads: head flashing should be placed over all openings except those completely protected by overhanging projections. At steel and wood lintels, the flashing should be placed under and behind the facing material with its outer edge bent down over the lintel to form a drip.

Wood framing and furring: nail attachment

Single nailing can provide satisfactory results if the methods in GA-216 are carefully followed. Nails should be spaced 7" o.c. on ceilings and 8" o.c. on walls along supports. Double nailing ensures consistent board-to-stud contact and fewer defects than does single nailing. A set of nails is driven into the field of the panel at 12" o.c., followed by a second set of nails 2" from each of the first nails. Edges and ends falling over supports are nailed at 7" o.c. on ceilings and 8" o.c. on walls. The total number of nails per panel is about 10% higher than for single nailing, but the number of nail spots that must be concealed is 20% fewer.

Sound in site planning

Site planning can reduce problems caused by exterior noise by 1. increasing the distance between the noise source and buildings, 2. siting buildings to minimize the effect of direct sound transmission, reflection, and reverberation from existing or possible future buildings, and 3. using natural topography, other buildings, barrier walls, and landscaping to shield buildings from major noise sources. An orientation that places rows of buildings parallel to each other results in a buildup or focusing of the noise by multiple reflection of the sound. Acoustically, the best orientation for a building occurs when its long axis is perpendicular to noise sources. It is acoustically better to have the end of a courtyard facing away from noise sources.

Hydronic heating sizing

Sizing of the main pipes and pump is based on the longest circuit, measured along the length of the supply pipe from the boiler to the coil and back along the return line to the boiler. Two guidelines apply: 1. Do not include the length of the coil itself in this circuit length. 2. No section of a floor panel main should be less than 3/4" in diameter.

Wrought steel products

Slabs are flat rectangular shapes with a width more than twice the thickness, which is usually less than 10". Blooms are rectangular shapes generally larger than 36 sq in. Billets are less than 36 sq in, more nearly square in cross section, and longer.

Carpet ease of maintenance: soiling resistance

Soiling is the result of dirt of soil particles deposited on the carpet surface by foot traffic or dust.

Passive cooling system

Solar collection and storage is integrated into building elements (walls, floors, ceilings, etc.) and does not rely on mechanical systems. Most effective when outdoor air temperature is below 85°F.

The simplest, least expensive type of water heater to install is also the least efficient. This describes which of the following types of water heaters?

Solar hot water heaters have expensive upfront costs. Gas water heaters are more efficient and have higher upfront costs than electric. Electric heat pump water heaters are efficient and have high upfront costs. Electric resistance water heaters are the simplest and easiest to install but are the least efficient.

Sound transmission

Sound is transmitted through buildings when wall, floor, or ceiling surfaces vibrate. This vibration may be caused by 1. the alternating air pressure of incident sound waves, called airborne sound transmission, or 2. direct mechanical contact or impact such as might be caused by vibrating equipment, a footstep, an object dropped on a floor, or a slamming door. Transmission as a result of direct mechanical contact or impact is called structure-borne sound transmission. In either case, vibrating surfaces generate new sound waves of reduced intensity in the space where the sound originates as well as in spaces adjacent to or above below the origin.

Concrete masonry units curing

Steam curing at atmospheric pressure accelerates the hardening process. This low-pressure steam curing, which is done in a kiln, accounts for most concrete masonry units produced in the United States. The main benefit of steam curing is rapid strength gain, which permits placing units in inventory within hours after they are molded. Two to four days after molding, the compressive strength of low-pressure steam-cured blocks will be 90% or more of the final ultimate strength. Moist-cured blocks cured at normal temperatures, on the other hand, develop strength slowly and have less than 40% of their ultimate strength 4 days after molding. Low-pressure steam curing produces units of lighter color than is usually obtained with moist curing.

Strain

Strain is the physical change in a body from the result of stress. Under stress, the size or shape of the body changes. Tensile stress strains a body by elongation and compressive stress shortens a body. Strain has no units because it is a ratio.

Knots in wood

Strength reduction is a result of the combined effects of the local cross grain, produced by knots interrupting the direction of the grain, plus checking that may develop in and around knots during drying.

Hydronic heating sizing

The critical choice, however, is not pipe size. It is relatively easy to distribute such small-diameter pipes within wall and floor/ceiling construction. Rather, the critical choice is the hot-water supply temperature: the higher this temperature, the smaller the convector units that discharge the heat to each space. However, higher temperatures endanger occupants, who may suffer skin burns if they touch exposed parts of the convectors or the distribution tree. Higher temperatures also can lead to steam within the boiler/distribution tree, although the system is under pressure and therefore the boiling point is greater than 212 degrees F. These systems are not designed to accommodate steam, and serious injury can sometimes result. A safer choice of average water distribution temperature is 180 degrees F, even though this temperature results in larger convectors. A slightly lower annual average energy consumption should accompany the lower distribution temperature. Baseboard convector selection is then made from the manufacturer's data tables. The two common baseboard types are RC, usually cast iron with a water-backed front surface and an extended rear heating surface, and finned tube, a metal tube with an extended surface in the form of fins, usually placed behind a metal enclosure.

The underside of the grand stair is exposed at the ground level, and runs adjacent to the accessible path. Adding a barrier at ______ will make this part of the stair ADA compliant.

The exposed underside of the stair at the ground level is an issue of head clearance, which is one of the most common errors/omissions in ADA design. Per the ADA Guidelines, "Vertical clearance shall be 80 inches (2030 mm) high minimum. Guardrails or other barriers shall be provided where the vertical clearance is less than 80 inches high. The leading edge of such guardrail or barrier shall be located 27 inches maximum above the finish floor."

Carpet appearance retention: compression resistance

The extent to which the pile will be compressed under heavy loads or by extensive foot traffic is called compression resistance.

Clay and concrete tile installation

The first course of tile should be elevated to the proper height by special tile units manufactured for the purpose, by wood strips, or by a raised fascia. Provisions should be made to permit water to drain from the roof beneath the tile. The first tile course should extend beyond the edge of the sheathing or fascia board by 1.5 to 3", according to the tile manufacturer's recommendations. Tile is usually installed with butts parallel to eaves and with tile perpendicular to eaves. Tile should be cut to follow the line of hips and valleys or special tile may be used. Valleys may be open, closed, or rounded. Most valleys in tile roofs, however, are open. Open ends of tile at valleys should be sealed with special units or mortar, but tile at valleys should not be sealed in a way that would prevent water that has penetrated through the tile to the underlayment surface from draining into the valley. Fan-shaped valley tile should not be sealed at the laps. Battens along valleys should be broken to permit trapped water to escape onto the valley flashing. Tile should lap valley flashing by at least 4". Open valleys should be left open 6" at the top and should taper wider at the rate of 1" for every 8' of length.

Unit of electric potential - the ohm

The flow of fluid in a hydraulic system is resisted by friction; the flow of current in an electric circuit is resisted by "resistance," which is the electrical term for friction. In a dc circuit this force is called resistance and is abbreviated R; in an ac circuit it is called impedance and is abbreviated Z. The unit of measurement is the ohm. Materials display different resistances to the flow of electric current. Metals generally have the least resistance and are therefore called conductors. The best conductors are the precious metals - silver, gold, and platinum - with copper and aluminum being only slightly inferior. Conversely, materials that resist the flow of current are called insulators. Glass, mica, rubber, oil, distilled water, porcelain, and certain synthetics exhibit this insulating property and are used to insulate electric conductors. Common examples are rubber and plastic wire coverings, porcelain lamp sockets, and oil-immersed switches.

Sound pitch

The hearing sensation produced by the frequency of sound is called pitch. The greater the number of vibrations per second, the higher the pitch. High frequency sounds such as squeaks and whistles are heard as high pitches, and low-frequency sounds such as rumbles and roars are head as low pitches. Pitch is expressed in tones of the musical scale.

Hardwood: maple

The heartwood of both sugar maple and black maple is light reddish-brown, and the sapwood, which in mature trees is several inches thick, is creamy white, slightly tinged with brown. The contrast in color between heartwood and sapwood in maple is much less pronounced than in oak, and the standard grading rules permit natural color variation in the wood.

Fire tube boilers

The hot gases of the fire are taken through tubes that are surrounded by the water to be heated. Firebox boilers place the boiler shell on top of the combustion chamber. Scotch-marine boilers feature multiple passes of the combustion gas through tubes. Fire tube boilers can be either dryback or wetback. Dryback designs have chambers outside the vessel to take combustion gases from the furnace to the tank. Wetback designs have water-cooled chambers that conduct the combustion gases.

Sound levels

The intensity of the vibration of a sound source depends on the amount of force that sets it into vibration. Sound levels are expressed in decibels (dB). The decibel scale extends from 0 dB (threshold of hearing to more than 120 dB (threshold of feeling). Zero decibels represents a fixed value of sound intensity that is slightly less than that of the faintest audible sound. Sound at 120 dB will cause the sensation of tickling in the ear. Sound at 180 dB, generated by some rocket engineers, can cause structural damage to buildings and can be fatal to humans. A decibel, which cannot be measured directly and has not fixed, absolute value, is the smallest change in sound intensity that can be detected by the average human ear. It is the logarithmic unit that expresses the ratio between a sound level being measured and a reference point. A decibel tells by what proportion one sound level is greater or less than another. The greater the sound level, the higher the rating on the decibel scale. Sound levels in decibel are calculated from either a ratio of sound pressure (P) or sound intensities (I) using a reference point that corresponds to the faintest audible sound. Pressure is a force per unit of area. Sound pressure at a given distance from a source is the force of moving air molecules spread over a spherical area and is expressed in dynes (units of force) per square centimeter. Power is expended when a force is applied over a certain distance in a given unit of time. Sound power in watts (units of power) is a basic expression of the flow of sound energy. Sound power is spread over a sphere of increasing area as the sound wave radiates farther from the source. Sound power per unit of area is called sound intensity (I) and is expressed in watts per square centimeter (W/cm2). The ratio in decibels between any measured pressure (P) and the reference pressure (P0) is called the Sound Pressure Level (SPL). The ratio in decibels between any intensity (I) and the reference intensity (I0) is called the Sound Intensity Level (SII).

Fig. 21.54a

The lower part of the tank often serves as a reserve space to hold a supply of water for a fire extinguishing system. In this case, only the water in the upper part is available for use as domestic (service) water. The amount stored must be enough to supplement what the pump will deliver during the several daily hours of high demand that occur in most buildings. The pump then continues, often for several hours, to replenish the house supply that had become partially depleted during the busy period. The suction tank is a buffer between the system and the street mains. It usually holds enough reserve to allow the pumps to make up the periodic depletion in the house tank. It refills automatically by flow from the street main that, consequently, will not suffer as much of a drop in pressure as it would if it were connected directly to the suction side of the house pumps. Neighboring water users are protected from the adverse effects of sudden demands within adjacent large buildings.

Elevator door and signal timing for hall calls

The minimum acceptable time from notification that a car is answering a call until the doors of that car start to close shall be calculated from the following equation: T=D/(1.5 ft/s) where T total time in seconds and D distance (in feet) from a point in the lobby or corridor 60" directly in front of the farthest call button controlling that car to the centerline of its hoistway door. For cars with in-car lanterns, T begins when the lantern is visible from the vicinity of hall call buttons and an audible signal is sounded. The minimum acceptable notification time shall be 5 second.

Gypsum plaster mixes and application

The minimum thickness and number of coats required for gypsum plaster depend on the plaster base. Three coats are required over metal lath and some gypsum lath installations. Two coats are adequate over most gypsum lath and over masonry and concrete bases. Three-coat work consists of a scratch coat, a brown coat, and a finish coat, each applied separately and allowed to partially set before the next coat is applied. The scratch coat derives its name from the cross-raking of the wet surface to improve the bond with the following brown coat. In two-coat work, the scratch coat is applied as in three-coat work, but is not cross-raked, and the brown coat is applied immediately, before the scratch coat has set. The finish coat is applied after the basecoat has set and is partially dry.

Air mixing plenum

The mixing plenum normally combines two air streams and includes three sets of dampers: one for the fresh air, one for the exhaust air, and a mixing damper between the two air streams. The mix of fresh air and recirculated air can thus be adjusted to suit the needs of the building's occupants.

Sanitary sewage disposal: DWV system: pipe material

The most common materials for drainage system piping are cast iron, galvanized wrought iron or steel, and plastic. Copper, brass, and lead can also be used, but their expense is usually prohibitive. Cast iron is the long-standing traditional material for drain piping. It is heavy, durable, and serviceable underground or in concrete. Hubless joints and fittings for cast iron pipe make it possible to run 3" cast iron drain lines in 2x4 wood stud walls. Hubless joints consist of a neoprene rubber sleeve gasket that covers the joint, a stainless steel band that fits over the gasket, and worm-screw clamps that compress the band against the pipe. Support must be provided at joints and at 4' intervals along a cast iron pipe. Older installations of cast iron drain pipe have bell-and-spigot or hub-and-spigot joints. Pipe sections are cast so that one end flares out into a bell or hub, which fits over the straight end, or spigot, of the succeeding section. The gap between the bell and spigot is packed with oakum or two hemp and filled with molten lead. Such joints have a shoulder on the inner surface and so must be installed directionally to prevent clogging. The direction of flow should always be from the spigot to the bell.

Water treatment: hardness

The most common type of domestic water treatment contains what is known as water hardness. Hardness refers to the amount of calcium and magnesium carbonate dissolved in the water; total hardness refers to the amount of carbonates plus several other compounds dissolved in the water.

Properties of soil: density and consistency

The most significant property of cohesionless soils is their relative density, which is described in such terms as very loose, loose, medium, dense, and very dense. Most coarse-grained soils are cohesionless. The most significant property of cohesive soils is consistency, described in such terms as very soft, soft, medium, stiff, very stiff, and hard.

Carpet comparative factors: rows, wires, and stitches

The number of pile tufts per inch in Axminsters is described in rows per inch; for Wiltons and velvets, in wires per inch. In tufted carpets, there are no weft yarns that can be related to the spacing of pile tufts. Therefore, lengthwise construction is expressed as the number of tufts per inch. To distinguish this count from tuft count across the carpet (needles), the term stitches is used.

Arrangement of elevator machines, sheaves, and ropes

The simplest method of arranging vertical travel of a car is to pass a rope over a sheave and counter-balance the weight of the car by a counterweight. Then, by rotating the sheave, the car moves up or down and requires very little energy to do it. This is essentially the scheme that is used on a majority of high-speed passenger elevators. When the four or more supporting ropes merely pass over the sheave T and connect directly to the counterweights, the lifting power is exerted by the sheave through the traction of the ropes in the parallel grooves on the sheave. This system is referred to as the single-wrap traction elevator machine. The function of sheave S is merely that of a guide pulley; it is called the deflector sheave. Double-wrap 1:1 roping provides greater traction than the single-wrap arrangement and is used in many automatic high-speed installations. A 1:1 roping arrangement gives no mechanical advantage. The 2:1 roping has a mechanical advantage of 2, which permits use of a high-speed, low-power, and, therefore, lower-cost traction machine. This arrangement is used for a wide variety of installations varying from medium-speed gearless passenger elevators to low-speed, heavy-duty freight units.

Which of the following heating and cooling systems is appropriate for a midsize to large building to minimize maintenance expenses?

The single duct at constant air volume system is simple and easy to maintain. By using a closed-loop heat pump, routine maintenance works have to be carried out in occupied spaces. This may entail additional maintenance costs. The system with hydronic convectors is known for simple installation and operation. Convectors are available in a diverse configuration and quality; temperature is easily controlled via thermostats. The variable air volume is self-balancing and one of the most economical to operate. Through-the-wall and packaged terminal units are known for high maintenance costs and short operation life. They are also expensive and inefficient in regions with harsh winters. Fan-coil terminals generally require a lot of maintenance. The systems cannot closely control humidity, and the routine maintenance is performed in occupied spaces.

Single Duct Variable-Air-Volume (VAV) systems

The single duct in a single-duct, VAV system requires less building volume for distribution than do multiduct systems, and the variation of air volume flow rate (rather than of air temperature) saves energy relative to the single duct with reheat. Depending on outdoor conditions and prevailing indoor needs, the central station supplies at normal velocity either a heated or a cooled stream of air. Automatic volume controls (linked to each zone's thermostat) adjust the volume admitted to that zone within an air terminal diffuser (often located above a suspended ceiling). When the central station is supplying cold air, a zone that needs more cooling will get more air; an unoccupied room with no internal gains, or a space with heat loss through an exterior wall, will get less air. Clearly such a system is well suited to serve the interior, always-hot zones of internal-load-dominated buildings. Less clear is its suitability for the perimeter zones of buildings in cold, cloudy conditions.

Properties of soil

The stability and structural properties of soil in relation to foundations are determined in large measure by the shearing resistance in most subgrade materials is the combined effect of internal friction and cohesion.

Carpet durability: insect and fungus resistance

The synthetic fibers in modern carpets contain no organic nutritive value and are, therefore, immune to attack by insects, such as carpet beetles and moths, and to fungi, such as mold and mildew.

Sound octaves and tones

The term octave, taken from musical terminology, is the interval between two sounds having a frequency ratio of 2:1. A pure tone is a sound having only one frequency, whereas a complex tone is a sound composed of a number of different frequencies.

Glass surface finishes: Sandblasting

The translucent finish obtained by sandblasting usually is rougher than that obtained by etching. Sandblasting is done by using compressed air to blow coarse, rough-grained sand against the glass surface. Often this is done through a runner stencil to produce a decorative design. Both etching and sandblasting reduce the strength of glass because these processes introduce surface flaw. Sandblasting, for example, reduces the strength of glass by about 50%.

Grounding and ground-fault protection

The vast majority of secondary wiring systems are solidly grounded. The reasons for this arrangement are several and varied Among them are: 1. To prevent sustained contact between the low-voltage secondary system and the high-voltage primary system in the event of an insulation failure. Such contact could cause a breakdown of the secondary system insulation and severely endanger the system's users. 2. To prevent single ground from going unnoticed until a second ground occurs, which would extensively disable the secondary system. 3. To permit locating ground faults with ease. 4. To protect against voltage surges. 5. To establish a neutral at zero potential for safety and for reference. Points 2 and 4 are highly technical, and a full explanation is beyond the scope of this book. Point 5 requires that the neutral in a single secondary system is: 1. Never interrupted by switches or other devices 2. Connected to ground only at one point - the service entrance 3. Color-coded white, natural gray, or by three continuous white stripes on any insulation color other than green, along the entire conductor length (in the US), for easy recognition.

Softwood: southern pine

The wood of all southern pines is much a like in appearance. The sapwood and heartwood often are different in color, the former being yellowish-white and the latter reddish-brown. However, the contrast in color between sapwood and heartwood in southern pine generally is not conspicuous in a finished floor, and the standard grading rules permit sapwood in all grade of southern pine flooring.

Background noise sources and levels

Theoretically, airborne sound travels from a point noise source in a spherical pattern. The sound level of a point noise source is reduced 6 dB each time the distance from source is doubled. But fast-moving traffic is a line noise source rather than a point source. Sound from a line noise source travels in a cylindrical rather than a spherical pattern. In order to reduce the noise level from a line source 6 dB, the distance between noise source and listener must be increased four times.

Effects of sawing

Theoretically, lumber is cut from a log in one of two distinct ways: 1. tangential to the annual growth rings, producing lumber called plain-sawn in hardwoods and flat-grained or slashgrained in softwoods, or 2. on a radial to the rings (parallel to the rays), producing lumber called quarter-sawn in hardwoods and edge-grained or vertical-grained in softwoods. In commercial practice, a piece sawn so that the growth rings when viewed from the end of the piece form an angle of 45 degrees or more with the wide face is classified as quarter-sawn, and when the rings form an angle less than 45 degrees it is classified as plain sawn.

Controlling noise with sound-absorbing materials

There are two basic noise reduction principles that serve as rough guides in determining the amount of treatment within a given room for satisfactory noise control: 1. the total number of absorption units in spaces with low ceilings should be between 20% and 30% of the spaces' total area of interior surface in s.f., and 2. to produce a satisfactory improvement in an existing space, the total absorption after treatment must be 3 to 10 times the absorption before treatment.

Carbon steel doors

There are two types of core construction. In one, cores are hollow and braced with steel stiffeners. Most are filled with the manufacturer's standard fireproof, rotproof, sound-deadening material. Insulated doors are filled with glass fiber or plastic foam insulation.

Architectural (AW) windows

There are, however, several window types that not included in the other classes, including horizontally pivoted windows, which are similar to vertically pivoted windows turned on their side, and side-hinged inswinging windows, which are similar to casement windows but swing inward. The major difference between the requirement of windows in the AW class and those in other other four classes is in performance requirement.

Prismatic batwing diffusers

These are either linear or radial; that is, they produce the batwing distribution either in one direction or in all directions. Note that the characteristic shape is more pronounced in the linear diffuser, which indicates better control of veiling reflections in that direction (usually corsswise). Fixtures equipped with these diffusers have good efficiency, low direct and reflected glare, and good diffusion. As with all enclosed ungasketed fixtures, the lens acts as a dust trap, necessitating frequent cleaning to maintain high output.

Reflector lamps

These are made in "R," "BR," "ER," and "PAR" shapes. They contain a reflective coating on the inside of the glass envelope that gives the entire lamp accurate light-beam control. Many reflector lamp types are available in narrow or wide beam design, commonly called spot and flood, respectively. R lamps are generally made in softy glass envelopes for indoor use, whereas PAR lamps are hard glass, suitable for exterior application. When using R and PAR lamps, the fixture acts principally as a lamp holder since beam control is built into the lamp. These lamps have an improved reflector design that increases their efficacy.

Chillers

These devices remove the heat gathered by the recirculating chilled water system as it cools the building. Chillers include both absorption and compressive refrigeration processes in a wide range of sizes. The single-effect, indirect-fired absorption chiller is attractive where central steam or high-temperature water (from solar collectors, as waste heat from an industrial process, a fuel cell, etc.) is available. This device uses the absorptive refrigeration cycle. Direct-fired absorption chillers use natural gas to power the cycle. In general, absorption equipment is less efficient than compressive refrigeration cycle equipment, although a cheap or even free heat source to power the cycle can rapidly overcome efficiency disadvantages. Absorption machines have fewer moving parts (and therefore requires less maintenance) and are generally quieter than compressive cycle equipment. They are environmentally attractive, despite their much higher waste heat output (about 31,000 btu/ton compared to at most 15,000 but/ton for compressive cycle equipment), because they do not use CFCs or HCPCs and because they require far less electricity to operate. Newer developments include the double-effect absorption chiller and the triple-effect chiller, each accompanied by an increase in efficiency. The compressive refrigeration cycle is used in the other types of chillers. Larger units are centrifugal chillers, whose compressors either can be driven by an electric motor or can utilize a turbine driven by steam or gas. (when a steam-driven turbine is used, the exhaust steam is often used to run an auxiliary absorption cycle machine. These two devices make an efficient combination, and the steam plant that supplies them in summer can supply heating in winter.) Centrifugal chillers usually require a cooling tower. Dual-condenser chillers can choose whether to reject their heat to a cooling tower (via the heat rejection condenser) or to building heating (via the heat recovery condenser). Somewhat smaller chillers use either twin screws or a scroll in place of a piston in the compressor, The screw compressor has a pair of helical screws; as they rotate, they mesh and thus compress the volume of the gas refrigerant. They are small and quiet, with little vibration. The scroll compressor uses two inter-fitting spiral-shaped scrolls. Again, the refrigerant gas is compressed as one scroll rotates against the other fixed one. Gas is brought in at one end while the compressed gas is released at the other. Quiet and low-maintenance, they are also more efficient than reciprocating compressors. Even smaller compressive-cycle machines are called reciprocating chillers. Usually electrically driven, they are often combined with an air-cooled heat rejection process rather than a cooling tower. This makes them a closer relative of the smaller direct refrigerant machines.

Encapsulated lamps

These lamps are sealed units intended for direct replacement of either a corresponding distribution-type incandescent lamp in the case of reflector units or general service incandescent lamps for reflectorless units. As a sealed unit, the halogen lamp is not replaceable, and the entire unit is discarded on burnout. Reflector units are available in a wide variety of beam patterns detailed in manufacturer's catalogs. Reflector lamps are also available with a variety of filters: so-called cool lamps that direct much of the heat out through the back of the lamp; high-efficiency units that reflect and concentrate the heat back on the lamp filament; lamps with ultraviolet (UV) filters for use in displays of UV-sensitive objects; and others.

Deep parabolic reflectors

These luminaires produce modified versions of the characteristic batwing distribution in the normal (crosswise) direction. Distribution in the perallel or lengthwise direction is circular (diffuse), indicating minimum beam control in that direction. These fixtures, like the batwing lens-type diffuser units, have high efficiency, high S/MH, low reflected glare, and low to very low surface brightness, making them usable in VDT areas. They are normally applied with the long axis in the direction of sight lines.

Direct refrigerant systems

These systems mostly eliminate the need for distribution trees of air or water, relying on a heating/cooling device(s) located in or adjacent to the space it is serving. They are typically used in buildings with a high perimeter-to-area ratio, tending toward smaller buildings.

All-water systems

These systems only heat and cool; the distribution trees are indeed slim. Air quality is dealt with elsewhere - either locally, by means of infiltration or windows; or by a separate fresh air supply system, such as a ventilated interior zone. A fan-coil terminal is often employed so that air motion occurs along with heating or cooling. (Sometimes the fan-coil unit is located against the exterior wall so that fresh air may be brought in and mixed with the room air through the fan.) Both baseboard and valence (above-window) units are also commonly available. Because air is handled so locally, there is very little mixing of air from one zone to another, making this attractive where potential air contamination (or smoke from a fire) is a special concern. It is also an easy system to retrofit. However, maintenance is high; filters in each fan coil must be cleaned, and drain pans are potentially problematic. Two-pipe water distribution systems provide either heating or cooling. One pipe is for supply, the other for return. In a typical large-building application, they are used for heating in winter, cooling in summer. This raises the question of what changeover period will be required, a problem made much easier with the following alternative system. Four-pipe systems allow quick changeover heating and cooling, utilizing two supply and two return pipes. A four pipe system also allows for simultaneous cooling and heating in different zones within a single distribution system.

All-water systems

These systems typically deal only with temperature control; air quality is left to separate systems. An especially familiar all-water application is the simple fan-coil unit. (Because units with the same name are used in air and water systems, this further blurs the distinction between these two HVAC families.) These units, which may be found above ceilings, below windows, or in corners, simply control the temperature (and, to a limited extent, the relative humidity) of the air already in the room, which is blown through the coils. Because water is often condensed from the room air when cooling is in progress, a drain line is required; water standing in drain pans is unhealthy. Exterior air intake grilles can easily be added when fan-coil units are located below windows to allow the local provision and tempering of ventilation air; this is especially common in motels, hotels, and apartments. Fan-coil units are inherently noisy due to the fan, so careful attention to sound ratings is required when background sound levels must be low. In offices, a relatively high background sound level can help to maintain acoustic privacy at the working-station; the sound of the fan-coil provides reassurance that some kind of air treatment system is at work. All-water perimeter systems with local fresh air can also take the simple form of operable windows with hot water finned-tube radiation.

Design strategies for cooling: High-mass cooling with night ventilation

This hot-dry summer design strategy must use outside air at subcomfortable nighttime temperatures to flush away heat stored during the daytime. The fewer the subcomfortable night hours, the greater the area of thermally massive surface that must be provided to store the day's heat. Also, because there are more hours of daylight and fewer of nighttime, the ventilation must occur quickly and thoroughly, probably using fans. (nightly wind velocities are typically lower than daytime velocities, because summer wind is often driven by regional solar overheating of the ground.) The building switches from a thermally closed condition by day (to exclude sun and hot outdoor air) to an open condition at night (to allow ventilation to cool the mass). This cooling strategy is highly compatible with passive solar heating strategies that rely on large areas of thermal mass, such as direct gain. It is suitable for large, high buildings, particularly those that have concrete (thermally massive) structural systems.

Design strategies for heating: isolated gain

This is a popular passive solar approach because it provides a uniquely sunny habitable space, alternately called a sunspace, greenhouse, sun room, or winter garden. This space experiences great variations in temperature - hot in the afternoon, cold before dawn - in order that the space behind it can be kept reasonably comfortable with solar heating delivered as needed. The sunspace usually has both southfacing vertical glazing and inclined glazing, increasing insolation in both winter and summer.

Double-duct systems

This is still considered the "Cadillac" of HVAC systems, not only because of its superior comfort control and flexibility for simultaneous heating/cooling zones, but also because of its high initial cost, large size, and high energy usage. The double-duct system is rarely installed now, except in hospitals. Building volumes needed for a double-duct system's three (two supply, one return) full-sized air distribution trees are harder to justify, given that VAV systems can provide acceptable comfort for most common spaces.

Design strategies for cooling: Natural ventilation cooling

This is the most obvious strategy suggested by the comfort charts presented earlier, in which higher air temperatures were offset by increased air motion. It may be the only passive strategy available in humid, hot climates in which temperatures are only slightly lower by night than by day. Buildings should be very open to breezes while simultaneously closed to direct sun. They may be thermally lightweight as well, because night air is not cool enough to remove much stored daytime heat. Very high humidity may be avoided only by sealing and air-conditioning buildings. Natural ventilation has two variations: cross-ventilation and stack ventilation. Cross-ventilation is driven by wind and is accomplished with windows. It relies upon rather narrow plans with large ventilation openings on either side. Thus, it is naturally compatible with daylighting. Stack ventilation depends upon very low openings to exhaust air; it is driven by the principle that hot air rises. Stack ventilation is generally weaker than cross-ventilation - except when there is no wind at all.

Design strategies for heating: indirect gain

This is the passive solar approach encountered least often, perhaps because a sheet of glass covering an opaque wall seems such a denial of "window." The mass wall behind the glass is usually 8 to 12 in thick, and should be of a dense and highly conductive material such as standard weight concrete or dense brick. Water in containers is also an option. An air space between the glass and the mass allows for the option to "vent" the mass wall, where cool air from the heated space behind the wall enters at the bottom, rises with solar heating, and then exits into the space behind near the ceiling. Sometimes this air space is made wide enough to admit a person for cleaning the inside surface of the glass, but operable casement or awning-type glazings are other cleanable options. The back surface of the mass (facing the heated space) should be kept clear of hangings or large furniture to facilitate radiant heat transfer to the space. Indirect gain is less popular than direct gain because it admits much less daylight and lacks a view to the south. Yet, relative to the other passive solar approaches, it has advantages of less glare, significantly less overheating on sunny days, and no fading of furnishings in direct sunlight. Another advantage is its large radiant heat contributions in the evening after sunny days. Many applications of indirect gain incorporate a smaller area of direct gain (window within the larger indirect-gain wall surface.

Tungsten-halogen (quartz-iodine lamps)

This lamp type is similar to the standard incandescent lamp in that it produces light by heating a filament. It differs in that a small amount of halogen gas (iodine or bromine) is added to the inert gas mixture that fills a small capsule constructed of quartz glass that surrounds the filament within the bulb of the lamp. This addition results in retardation of filament evaporation, which is the usual cause of incandescent lamp failure, and thereby extends lamp life. Due to the lamp's high filament temperature, the bulb envelope is generally made of quartz or a special high-temperature glass, which can withstand high temperatures better than glass; this, in turn, gave rise to the alternative name - quartz-iodine - that is sometimes applied to this lamp type. Another result of high filament temperature is that the gas pressure inside the quartz envelope is elevated and the lamps have been known to rupture violently, spraying hot quartz fragments over a wide area.

Dual-duct, constant-volume systems

This mechanical system requires two complete distribution trees—one system is devoted to cold air and the other to hot air. During peak summer months and in winter, the all-cooling system or the all-heating system, respectively, does all the work. The rest of the year, air from the two steams is mixed at each zone's terminal to achieve the desired zone temperature. Both temperature and air volume can be controlled with this system, which offers increased comfort under reduced load conditions than a traditional single-duct VAV system does. This system has a high initial installation cost; the two distribution trees take up a significant portion of the building; and it consumes more energy than a single-duct VAV system.

In-plane irregularity in vertical and lateral force system

This occurs when there is irregularity in the location of lateral force systems on the vertical face of a building, resulting in localized structural damage.

Nonparallel lateral force-resisting system

This plan occurs when the lateral systems are not placed in parallel configurations due to the design of the structure. This arrangement leads to torsion and instability, creating localized damage.

Design strategies for cooling: High-mass cooling

This strategy is for warm, dry summers, when the extremes of hot days are tempered by the still-cool thermal mass of a building. Cool nights then slowly drain away the heat that such mass accumulates during the day. The thermal mass can be in floors, walls, or roofs, but will need a sink to which it can reject its heat by night. The roof has the advantage of radiating to the cold night sky, but is should be protected from exposure to the sun by day. The masonry courtyard-type buildings of the Mediterranean are indigenous examples of this passive cooling strategy; their courtyard floors and roofs can be protected with movable shading devices (toldos) by day, then opened to night-sky radiation. Roof ponds are a form of high-mass cooling for one- and two-story buildings. Because they require only the roof to be massive, they allow for considerable design freedom in walls and fenestration. Where cooling is the only objective, this approach uses water that is stored between the metal ceiling and the roof insulation; by night, the water is pumped (and/or sprayed) over the exposed roof surface and allowed to trickle back through the insulation to the storage pond. At lower latitudes (with high winter sun altitudes), roof ponds can be used for passive solar heating as well. This strategy uses sliding panels of insulation over bags of water; the panels slide open on winter days to collect sun and open on summer nights to radiate heat to the sky. Another variation on high-mass cooling depends upon earth contact. The earth acts as a heat sink, keeping walls and floors (even roofs when earth covered) cool. However, if the earth is allowed to continue to act as a heat sink in winter, heating needs could be greatly increased. Thus, a strategy for summer contact and winter isolation might be appropriate.

Single-duct with reheat

This system (along with VAV) has the smallest distribution tree of this class, because at each zone the only object added to the duct is a small reheat coil (heat provided by steam, hot water, or electric resistance). (technically, this could also be called an air and water system.) The central station provides a single stream of cold air that must be cold enough to meet the maximum cooling demand of any one zone. All other zones reheat this air as needed. In cold weather, outdoor air at temperatures as low as 38 degrees F can be used; the colder this single central airstream, the less air need be circulated (and the smaller the ducts). For buildings with large interior zones in most US climates, however, the central airstream must be cooled most of the time; then more energy must be spent to reheat the airstream at most zones. These systems thus are notorious for energy wastage, although careful engineering can make them attractive for some climates.

Water loop heat pumps

This system can be an all-water system but can also be configured with a central outdoor air supply, making it an air and water system. Heat pumps either draw heat from a water circulation loop in heating mode or discharge heat in cooling mode.

Hydronic and coils

This system combines a perimeter hot water heating pipe with an overhead air-handling system. A boiler with a tankless coil supplies domestic hot water. The boiler's heat output supplies both the perimeter loops and a coil in the air-handling unit of the duct system. The total heating load is met by the combination of radiant heat generated by the perimeter loop and heated air from the overhead air-handling system.

Fan-coil with supplementary air

This system uses a fan at each unit, rather than high-velocity primary air, to move the mixture of supply and room air through the unit. A typical arrangement is a supply air plenum over a corridor, feeding horizontal fan-coils above the suspended ceilings of spaces on either side. These fan-coils draw some supply air and mix it with room return air to maintain desired temperatures. If condensation and resulting pans of standing water are to be avoided, the supply air must be sufficiently dehumidified. Fan-coils are very widely used, both in conjunction with conditioned supply air (air and water) or as stand-alone units that take in their own fresh air at the perimeter (all-water), or even as room-air-only units.

Portland cement plaster application

Three-coat applications are required over metal reinforcement and are sometimes also used over a rigid base. They consist of a scratch coat, a brown coat, and a finish coat, totaling 7/8" in thickness. Each coat is applied separately and allowed to set partially. The scratch coat and brown coat are sometimes referred to as base coats. The first (scratch) coat provides mechanical keying with the reinforcement and a rigid surface for the following coat. Over a rigid base, a dash bond coat is sometimes used instead of a scratch coat. The second (brown) coat provides additional thickness and strength and ensures a level surface for the application of the final decorative finish coat. Each coat should be moist-cured before the following coat is applied.

Glass surface finishes: Tinting

Tinting is not really a type of surface finish, because it involves adding special ingredients to the basic glass batch. However, it is used widely to produce glass with heat-absorbing and glare-reducing qualities. Many different ingredients can be added to glass to produce various tints. Ferrous iron, for example, imparts a bluish-green tint to glass, cobalt oxide in combination with nickel imparts a grayish tint, and selenium is used to make bronze-tinted glass. These different ingredients are added to the glass mixture at the very beginning of the melting process Float glass can be tinted in this manner. Tinted glass expands more than untinted glass due to its greater absorption of heat, which must be taken into account when designing the surrounds of the glass.

Valley flashing for wood shingles

To avoid restricting the delivery of a valley and to prevent water splashing from a steep slope onto the shingles of a lower slope, the edges of the shingles on the lower slope should be lined up at least 1" farther back from the valley centerline than those on the steeper slope. As an alternative, a vertical ridge, or waterstop, can be made by crimping the metal up in the center of the valley. Valley sheets should be edge up and back approximately 1/2" toward the venally centerline. This provides an additional waterstop, directing water down the valley. The open portion of the valley should be at least 4" wide, but valleys may taper from a width increase at the ratio of 1/2" per 8' of length, becoming wider as they descend.

Gutters and Downspouts

To design a gutter and downspout (leader) system for a steeply sloped roof, use the following steps: 1. Lay out the roof plan and determine the location of downspouts. 2. Size the downspouts to verify that their placement is satisfactory. To do this, multiply the rainfall amount from the code by the area of the roof to be served by each downspout. Select the downspout size from tables in the applicable plumbing code. 3. Size the gutter based on the roof area to be served by each section of gutter. In most designs, one-half of each gutter section spills into each downspout, so the roof area served by each gutter section will be one-half of that served by each downspout, but this may vary, depending on the layout of the system. Whatever the area served, size the gutter by entering the tables in the applicable code with the area to be served, the rainfall amount, and the slope of the gutter and select the gutter size directly. The slope of a gutter influences the amount of water it can carry in a given time. 4. If there is a horizontal element, other than the gutters, in a gutter and downspout system, size it by entering the tables in the applicable code with the area to be served, the rainfall amount, and the slope of the pipe and select the pipe size directly. As with a gutter, the slope of a horizontal of water it can carry in a given time.

Roof drains and pipes

To design a roof drainage system for a low-slope roof, use the following steps: 1. Lay out the roof plan and determine the location of the roof drains. 2. Determine from the layout the roof area to be served by each drain. 3. Size the leaders connected to each roof drain. To do this, multiply the rainfall amount from the code by the area of the roof to be served by each leader. Select the leader size from tables int he applicable plumbing code. 4. Size the horizontal portion of a low-slope roof system in the same way as described earlier for a steep-slope roof design.

Cabinet installation

To ensure plumb and level installation, remove high spots and shim low spots in walls and floors. Remove the wall base and chair rail from behind cabinets to ensure a flush fit. Install wall cabinet first, beginning with a corner unit. Insert screws through hanging rails built into the backs of cabinets at both the top and bottom. After the cabinets have been leveled and plumbed and doors perfectly aligned, tighten the screws. Start installing base cabinets in a corner. After installing the base corner unit, use C-clamps to hold adjacent cabinets in alignment. Then use T-nuts to fasten them together. Check each cabinet from front to back and across the front edge with a level as it is attached to the wall. The front frame should be plumb and the top should be level. Attach base cabinets with screws through the back frame into wall studs. After base cabinets have been secured in place, install the countertop and finish the toestrip with a tile, resilient, or wood base.

Fan-powered VAV systems

To maintain minimum fresh air, VAV terminals are usually set so that they cannot be entirely closed off, ensuring some outdoor air at all times. If this fresh air minimum, entering at low velocity, does not provide the desired air motion and mixing within the room, VAV terminals can be equipped with fans, which are activated as needed with decreasing incoming air volume. These self-contained fans mix room air with incoming air to provide an airstream of the right temperature and velocity to maintain comfort. This approach to VAV is sometimes taken when simultaneous heating and cooling are needed, such as at perimeter zones, which can generate sizable heating needs while the rest of teh building needs cooling, Another approach is to utilize an induction-type VAV terminal, with which air heated by electric lights is induced to join the incoming cool airstream. Greater heating needs often require the use of reheat terminals supplied by a circulating hot water system or by electric resistance heating. This reheat application is more energy efficient than the standard CV reheat system, because a much smaller voume of air is first cooled, then reheated. The water or electric coils can be incorporated either in the VAV terminal or in the ductowrk between the terminal and the space it serves.

Glass surface finishes: Enameling

Translucent and solid colors can be produced on glass surfaces with vitreous enamels fired on at high temperatures. The firing process also imparts a partial or full temper to the glass. This type of glass is used primarily for spandrel areas and other parts of curtain wall construction.

Double-duct, constant-volume systems

Two complete distribution trees are required; at the height of summer the cooling airstream does all the work, whereas in the coldest winter conditions the heating airstream carries the load. Most of the time, air from these two streams is mixed to order at each zone's air terminals. Because both temperature and volume can be controlled, this system offers better comfort under reduced load conditions (for example, an only partially occupied room) than does the single-duct VAV system. However, it is much more expensive to install, consumes much building volume for the two distribution trees, and usually consumes more energy than the single-duct VAV system that has largely replaced it.

Types of constructions

Type I is the most fire-resistant type of construction. Examples: protected steel and reinforced concrete structures and high-rises. Type II is noncombustible construction. Similar to Type I but less fire-resistant. Examples: unprotected steel buildings and school buildings. Type III is ordinary construction. Exterior walls and structure are noncombustible or of limited combustion. Example: strip mall. Type IV is heavy timber construction, also commonly called mill construction. Type V is wood frame and is the most combustible. A typical home is an example.

Cement Types

Type I: Normal cement used for most construction. Type IA: Normal cement, which is air entraining. Type II: Moderate resistance to sulfate attack (used when in contact with water with high concentrations of sulfates). Type IIA: Moderate resistance, air entraining. Type III: High early strength (hardens more quickly; used when reduced curing time is required). Type IIIA: High early strength, air entraining. Type IV: Low heat of hydration (used in massive structures such as dams, where emitted heat might raise the temperature of the concrete to damaging levels). Type V: High resistance to sulfate attack (used when in contact with water with a high concentration of sulfates).

Barriers and retarders materials

Types of vapor retarders range from asphalt-coated organic felts to asphalt-coated glass fiber mats. Venting sheets with granulated undercoats allow for positive venting of any trapped gasses under the roof membrane. Types of fire barriers include fiber glass-based slip sheets and liquid applied intumescent deck coatings.

Radiant panels with supplementary air

Typically, ceiling or wall panels contain heated or cooled water, relying on large surface areas for radiant heat exchange. Centrally conditioned, temperature-controlled fresh air is delivered to the spaces served by the system at a constant volume. The panels in the ceiling or the wall must be kept clear of obstructions.

Conventional steel framing

Under normal conditions, the joints in conventional structural steel building grids are subjected to both shear and moment forces. Unless some means is employed to resist these forces, the frame will be inherently unstable and subject to wracking and ultimate collapse. The American Institute of Steel Construction (AISC) lists there methods for solving these inherent difficulties as types of steel frame construction. In Type 1, connections must be made sufficiently rigid to resist all forces that will occur without significant change in the angle between framing members (beams, girders, columns). In Type 2, diagonal bracing or shear panels are introduced to resist moment forces. Thus, most joints need resist only shear forces. Type 3 is a semirigid system in which the joints are sufficiently rigid to resist the applicable moment forces but not as rigid as those required in Type 1.

Dynamic thermal effects

Under static conditions, heat flow is primarily a function of temperature difference (the driving force) and thermal resistance (the resisting force). Under dynamic conditions, these two factors are still important, but heat storage in the envelope assembly itself becomes a compounding issue. Heat storage is a function of the density of a material and its specific heat; the product of these two properties is known as thermal capacity. Thermal capacity can (but will not always) reduce heat flow via storage. Density is the wright of a material per unit volume. For a fixed volume of material, greater density will permit the storage of more heat. Specific heat is a measure of the amount of heat required to raise the temperature of a given mass of material by 1 degree. It takes less energy input to raise the temperature of a low-specific-heat material than that of high-specific-heat material. Thermal capacity is an indicator of the ability of a fixed volume of material to store heat. The greater the thermal capacity of a material, the more heat it can store in a given volume per degree of temperature increase. Thermal capacity for a material is obtained by taking the product of density and specific heat. Time lag is a measure of the delay in the flow of a pulse of heat through a material that results from thermal capacity.

Concrete masonry units curing

Units cured by application of saturated steam in an autoclave under a pressure between 125 and 150 psi are called autoclaved units. The principal benefits of high-pressure steam curing are high early strength and greater stabilization against volume changes caused by varying moisture conditions. Within 24 hours of molding, usable units can be produced that have a permanent compressive strength equal to that of moist-cured units only after they have been cured for a full 28 days.

Water treatment: scaling and soaping

Using a water softener alleviates both scaling and soaping problems. An ion-exchange water softener contains a sodium-zeolite exchange medium which develops sodium ions. These then interact with calcium (or magnesium) ions in the water.

Slate installation

Valleys may be either open, closed, or round. Open valleys are protected using metal flashing. They should start with the slate 4" apart at the top and widen uniformly from top to bottom at a rate of 1" in every 8'. In closed valleys, the slate is cut to abut in the valley, and metal flashing is woven in as the slate is installed. Flashing is not required in properly installed round valleys. Round valleys require considerable underlying support and special slate sizes. Considerable expertise is needed to properly install round valleys. Round valley slates are sometimes bedded in elastic cement. Round valleys built by inexperienced or insufficiently skill personnel should be flashed. Round valleys susceptible to ice damage should always be flashed. Round valley flashing may be metal or bituminous materials. In all types of ridge and hip conditions, the top regular slate courses should have their edges set in elastic cement to resist wind uplift. The joint between ridge slates and the overlap in comb ridges should be sealed with elastic cement. Some slate roofing is installed with elastic cement in other locations, such as along flashing lines an din the field of the roofing. Some slate roofing is installed with no elastic cement whatever, and experiences no leaks as a result. The absence of elastic cement does not, in itself, mean that there is a problem or that the installation is inferior.

Controlling airborne sound transmission

Variables that affect the control of airborne sound transmission to provide a suitable acoustical environment include 1. the frequency and sound level of the sources, 2. the sound level that will be acceptable within the space, and 3. the sound-reducing characteristics of the intervening construction. Methods to control airborne sound transmission include 1. selecting walls and floor and ceiling assemblies that reduce transmission by vibrating, 2. closing paths of direct air transmission, and 3. installing sound-absorbing materials within the free air space of frame construction. Usually, a combination of these control measures is necessary to achieve suitable sound privacy.

Energy storage

Water storage tanks are one common approach to storage. On typical winter days, the total internal heat generated by a large building can be somewhat greater than its total need for heating at the perimeter zones. Instead of being thrown away as exhaust air, this surplus heat is captured and stored in large water tanks, from which it can be withdrawn and used on cold winter nights and weekends. In the summer, chillers can work at night, when efficiency is high because cool outdoor air helps the refrigeration cycle reject its heat. By storing the coolth produced, less work need be done by chillers during the next day's peak, when electric rates are highest and operating efficiency is lowest. Ice storage tanks are another storage approach. Because they take advantage of the latent heat of fusion (143.5 btu/lb of water at 32 degrees F), such units can store far more energy in a given-size tank than can water. Ice can be made in several ways. A common method is to form ice as a layer around a pipe that carries refrigerant in a closed circuit through the tank. Control of the thickness of this layer is important, because if too little ice is made at night, too little cooling will be available the following day. In another method, ice is formed and thawed by circulating a brine through coils in cylindrical water tanks. Other methods form ice on plates, then harvest it in an insulated bin.

Water-resistant wallboard

Water-resistant (WR) boards are used in toilet rooms, bathrooms, kitchens, utility rooms, and other humid areas. They are not recommended for high-moisture areas such as shower rooms, saunas, or steam rooms. They can be painted or used as a base for adhesively applied cement, metal, and plastic wall tile. Water resistance is achieved by a multilayered covering of chemically treated paper and a gypsum core formulated with asphaltic additives. Edges usually are tapered. Installation is the same as for regular wallboard.

Multiple sound relfection

When a sound is produced in a room having reflective surfaces, sound waves are reflected back and forth by these surfaces, and almost immediately the room is filled with sound waves traveling in every direction. Multiple reflection causes a buildup of sound intensity to a level greater than there would be if no reflection occurred. It makes noises unnaturally and unnecessarily loud and makes noise last longer.

Reverberation

When a sound source is stopped, the reflected waves do not cease to exist at that instant but continue to travel back and forth, reverberating (bouncing) between room surfaces. The total sound energy in the room gradually diminishes due to the partial absorption of the sound at each contact with a sound-absorbing surface. Reflected sound waves strike the ear of a listener in rapid succession, so the listener does not hear them as distinct repetitions of the original sound. Instead, the listener hears the original sound being drawn out or prolonged after the source is stopped and steadily dying out until it becomes inaudible.

Channel siding application method

When it is not possible to nail directly into a stud, either a twist nail or a self-clinching nail should be used to attach the corner of the siding to nonlumber sheathing. A twist nail is a slender copper or aluminum nail with flat head and medium needle point designed for twist clinching, that is , manual twisting of the exposed shank. A self-clinching nail is designed so that its shank clinches automatically when the nail has been fully driven.

Gray & white cast iron

When molten cast iron solidifies, carbon in the iron may remain chemically combined in the form of iron cabide or may separate out a s graphite. White cast iron contains carbon mainly in the chemically combined form (iron cabide), which makes this metal hard and nonductile. In gray cast iron, the carbon is chiefly in the form of graphite flakes, which impart the characteristic gray fracture and promote machinability and resistance to wear.

Chimney and side wall flashing

When shingles butt against vertical surfaces such as side walls, dormers, or chimneys, individual flashing units of corrosion-resistant metal should be inserted between each course of shingles. These metal flashing units should be folded from a width of 19" material and have a standing leg 6" high and a flat leg 4" wide on the shingle. The length of this flashing should be 3" greater than the exposure of the shingles. Side wall exterior finish materials should cover the standing leg. At masonry chimneys, a stepped counter flashing of corrosion-resistant metal should cover the standing leg of the flashing units and be trimmed off just above the surface of the shingles.

Carpet yarn dyeing methods: skein and package dyeing

When smaller quantities of colored yarn are required, skein dyeing is often used. In this method, skeins of natural-colored spun yarn or continuous filament fibers are immersed in vats of hot dye. In packaging dyeing, yarn is wound on a perforated tubes and dye is forced through the perforations to soak the yarn.

Single-duct VAV systems

When the building uses only one or a few central fans, a VAV system will require smaller fans because the fans need meet only one peak condition at a time and do not have to be sized for all zones' peak flows. The variation in demands on the fan can be met either by selecting variable-pitch blades or (less expensively) by varying the speed of the fan.

Anchorage requirements

When the ratio of the exposed building surface to the width of the building is large, high wind forces tend to cause translation (lateral movement) of the superstructure. When the wind forces are not symmetrical, building rotation can occur. Forces tending to cause translation and rotation are transferred to a foundation by the first floor acting as a diaphragm. Connections anchoring the superstrutcure must develop enough shearing strength to transmit these forces to the foundation. When a first floor doe not have enough rigidity to provide diaphragm action, high shear and bending stresses may be produced in the foundation walls. In this case consideration should be given to the use of shear walls, pilasters, or bond beams to stiffen the walls.

Pitch pockets in wood

Whether pitch pockets affect strength depends on their number, size, and location in the piece. Their effect on strength has often been overestimated. Certain restrictions are imposed in the lumber grading rules.

Water supply pipe material: copper

While the piping itself is durable, the joints are weaker than the piping and are subject to damage from water hammer, which necessitates having air chambers at the ends of supply lines. Copper supply piping falls into two major categories: rigid pipe and flexible tubing. Flexible tubing also provides more options for connections. Soldered fittings, which require the use of a torch, and flared and compression fittings can all be used. A flared fitting is made by slipping a flare nut over the end of the copper tube, reforming the end of the tube so that is has a flared tip, then screwing the flare nut onto a threaded fitting. A compression fitting is similar, except tat the nut nears against a brass ferrule as it is screwed into the fitting rather than against the flared end of the tube. A push-in connector for copper tubing is also available. It consists of stainless steel and neoprene grabbers mounted in a nylon body.

Condensing water equipment

With chillers, there must be a way to reject the heat that is removed from the recirculating chilled water system. Reject heat is handled by the condensing water system, which serves the condensing process within refrigeration cycles. For larger buildings, the condensing water requirement is most likely to be met by a cooling tower. When fouling of the condensing water system cannot be tolerated, an alternative approach, called the closed-circuit evaporative cooler, is taken. Usually used to cool the refrigerant directly, it can also be used for the condenser water, as well as on water loop heat pump systems. Either refrigerant or condenser water is protected within an always-closed loop, while a separate body of water is recirculated though the cooler, with steady evaporation and attendant problems. It requires much less makeup water than the cooling towers.

Glass surface finishes: Reflective coatings

With the advent of the glass-enclosed high-rise, an entire new family of architectural glasses was developed to control the transmission of solar energy into buildings. These products have a thin reflective coating applied either 1. to one surface of a single sheet of glass or 2. to an inside surface of a laminated or insulating glass unit. Two processes are used to apply reflective coatings to glass: 1. the pyrolytic process, in which the coating material is sprayed onto heated glass and becomes fused to the glass surface, and 2. vacuum deposition, in which the glass is bombarded with metallic ions, which form an integral molecular bond with the glass. Under appropriate lighting conditions, reflective coated glass can become a type of one-way mirror, permitting vision only to the side with the greater amount of light. During the daytime, it creates a mirror-like effect from the outside of a building, while from the inside the glass is transparent. At night, when the interior lights are on, the effect is reversed although to a lesser degree. Reflective coatings can be made to reflect varying degrees of light and heat, providing control over the solar energy transmitted into a building.

Combining strategies: daylighting

With windows that face east and west, daylighting problems can occur due to the low sun altitudes in morning and evening that result in glare and unwanted summer heat gain.

Wood heating devices

Wood stoves are frequently used as the sole mechanical heat source for an entire building, such as a residence or a small commercial building that is passively solar heated. Because radiant heat is the dominant form of heat output, the areas that "see" the stove get most of the benefit. However, circulating stoves convert a larger portion of their heat to convected heat, which produces a layer of hot air at ceiling level. By providing a path between rooms at the ceiling, this hot air will slowly spread throughout a building; it also easily finds its way upstairs, because warm air rises. The more thermally massive the ceiling construction, the longer it will store and reradiate the heat from this warm air mass. The fuel leading from a wood stove carries very hot gases that are a potential source of heat (and pollution). The flue can be exposed to a space, making its radiant heat available, or simple heat exchangers can be constructed (such as the preheating of domestic hot water). Catalytic combustors, a recent development, reduce the air pollution from wood burning. These devices are honeycomb-shaped, chemically treated disks as mush as 6" in diameter and 3" thick. They are either inserted in the flue or built into the stove itself. When wood smoke passes through the combustor, it reacts with the chemical and ignites at a much lower temperature; this causes gases to burn that otherwise would have gone up the flue. The result is more heat produced, less creosote buildup in the flue, and fewer pollutants in the atmosphere. Like the catalytic converters in autos, these devices impose limits on the fuel; plastic, colored newsprint, metallic substances, and sulfur are ruinous to combustors, which means that the stove must be used as a wood burner, not a trash incinerator.

The client has chosen the Primacoustic 36" Hexus Panels. How many panels are needed to have a total absorption of 65 sabins?

a = SAC x S NRC = average SAC for frequency bands 250, 500, 1000, and 2000 Hz Each panel is 5.7sqft 65= 1.05 x (5.7sft x N) N= 10.86, 11 panels

Other water treatments

a. Aeration (oxidation) b. Corrosion control c. Softening d. Nuisance control e. Fluoridation f. Distillation

Audible and visual alarm devices

a. Audible signals b. Visible signals

Passive solar heating performance

a. Glazing performance b. Direct-gain (DG) systems c. Sunspaces (SS) d. Tombe walls (TW) e. Water walls (WW) f. Load collector ratio (LCR) annual performance g. Variations on reference systems h. Thermal lag through mass walls i. Internal temperatures

Air and water systems

a. Induction b. Fan-coil with supplementary air c. Radiant panels with supplementary air d. Water loop heat pump

Special fluorescent lamps

a. Low-energy lamps b. U-shaped lamps c. Ecological friendly lamps d. UV lamps

Filtration

a. Sedimentation b. Coagulation c. Flocculation d. Slow sand filters e. Diatomaceous earth filters f. Direct filtration g. Membrane filtration h. Cartridge filtration i. Other filters

All-air HVAC systems

a. Single-zone systems b. Single-duct VAV systems c. Fan-powered VAV systems d. Multizone systems e. Single duct with reheat f. Double-duct systems

Passive solar heating guidelines

a. Whole-building heat loss criteria b. Solar savings fraction (SSF) c. Thermal mass d. Orientation e. Roof ponds f. Active solar heating

Heating-only systems

a. Wood heating devices b. Electric resistance heaters c. Gas-fired heaters d. Ceiling electric resistance heat e. Hot water boilers f. Hot water baseboard and radiator systems g. Radiant panels h. Hydronic heating sizing i. Hydronic zoning j. Heating equipment efficiency, combustion, and fuel storage k. Warm air heating systems

Reflection of sound

allows the same laws as the reflection of light from a mirror: 1. the direction of travel of the reflected sound always makes the same angle with the surface as that of the incident sound, that is, the angle of incidence equals the angle of reflection; and 2. the reflected sound waves travel in exactly the same manner as they would if they had originated at an "image" of the sound source, located the same distance behind the wall as the real source is in front of the wall.

Plywood panels

always have an odd number of layers for balanced construction, the minimum number being three. A layer may consist of a single thickness of veneer, or it may be a lamination of two veneers with their grain running int he same direction.

Deluge systems

are dry systems with open heads. Separate detectors cause valves to open for water to enter the pipes. Therefore, all heads emit water at the same time.

Select and finish grades in wood

have good appearance and are used where a natural or high-quality paint finish is natural or high-quality paint finish is required. They are used for the highest quality of interior and exterior finish, trim, moldings, paneling, flooring, and siding.

Warp in wood

is a deviation from a true or plane surface and includes bow, crook, twist, cup, or combinations of these. Warp is measured at the point of greatest deviation from a straight line.

Clay waterproofing

is a layer of an expanding material called bentonite clay. When wetted, bentonite expands to between 10 & 15 times its dry volume. It is available loose for mixing with water and spraying in place. It is also available in dry sheets between cardboard, adhered to a drainage board, and adhered to a plastic sheet. Bentonite is especially useful in tight locations where access is not available to install membrane waterproofing. This is often the case where existing construction occurs.

Waterproofing

is a membrane, coating, or sealer used on concealed locations to prevent water from entering a building. Waterproofing will work even when the adjacent water is under hydrostatic head. Vertical waterproofing is usually used in conjunction with a foundation drainage system. Horizontal waterproofing systems also require a positive means of draining away water that penetrates the wearing surface. There are three basic types of waterproofing materials: membrane, clay, and cementitious.

Smelting

is a metallurgical operation by which metal ore is heated to separate the metal in it from impurities with which the metal may be chemically combined or physically mixed. The separation of chemically combined iron and oxygen is called reduction. Pig iron is made in a blast furnace by smelting, which extracts the iron by reduction of its oxide and by physically separating it from other impurities.

Annealing

is a thermal treatment that is applicable to both heat-treatable and non-heat-treatable alloys and to cast and wrought products. It is done by elevation the temperature of the metal to between 600 and 800 degrees F and then cooling it slowly. The purpose of this treatment is to relieve internal stresses and to return the alloy to its softest and most ductile condition. Annealing is usually performed to condition the metal for severe forming operations. Subsequent working processes increase the mechanical properties of the non-heat-treatable alloys. The mechanical properties of hear-treatable alloys may be increased by appropriate thermal treatments after forming operations have been completed.

Spot welding

is a type of resistance welding in which the components are joined by a series of spot welds, rather than a continuous line of weldment as in other techniques. It is produced by the resistance heating of a small area between two cylindrical electrode under pressure.

Closed-loop system

is a wet pipe system in which the water filling the pipes is also used as the circulating water for heating, ventilation, and air conditioning water heat pumps.

Resistance welding

is generally a shop process in which the components are butted together and heat is generated in the seam by the resistance of the metal to the passage of an electric current. An electrode in contact with the component introduces the current. Welded wire fabric is usually produced using resistance welding.

Factory & shop llumber

is intended primarily for further manufacture into windows, doors, millwork, and similar items. Therefore, the grade of a piece is based on the amount of usable clear wood that can be cut from it.

Structural lumber

is lumber that is 2" or more in nominal thickness, and is intended for use where working stresses are required. Structural lumber is sometimes called stress grade lumber. Working stresses (allowable unit stresses) for commercially available species and grades are published by the AF&PA's NDS. NDS is the industry-recognized standard of proper engineering practice for structural wood design.

Steel roof decking

is made from 22-, 20-, 18-, and 16-gauge steel in depths from 1-1/2" to 7-1/2". It can span from 4'-6" for lightest decking to as much as 30' for heavy, deep cellular decking. Rib openings in 1-1/2" roof deck are either 1" wide (narrow rib), 1-3/4" wide (intermediate rib), or 2-1/2" wide (wide rib).

Shrinkage or swelling parallel to the grain (longitudinally with the height of the tree)

is practically negligible and has little significance in construction applications. Across the grain, however, wood will shrink appreciably in both width and thickness. Shrinkage is greatest in the direction tangent to the annual growth rings and is about one-half to two-thirds as much across these rings (radial).

Foil-backed wallboard

is regular wallboard with a bright-finish aluminum foil bonded to the back to act as a vapor retarder, eliminating the need for a separate vapor retarder in an exterior wall assembly. When the reflective surface faces a 3/4" wide dead air space, it can also provide increased insulating performance. Installation and edge treatment of foil-backed gypsum board are the same as for regular wallboard.

Checking in wood

is separation across the growth rings, occurring as a surface check if present on only one surface or as a through check if it extends throughout the entire piece. Checking is measured by depth and length. Checks seldom affect stength but do affect appearance, especially in select grades of softwoods where large grain separations are objectionable. In structural lumber, checks have little, if any, effect on tension of compression members. Checks may reduce shear resistance, and limitations in the grading rules are based on this reduction.

Dry-bulb (DB) Temperature

is the ambient air temperature as measured by a standard thermometer, thermocouple, or resistance temperature device. DB temperature can be used in combination with globe temperature and air velocity to calculate mean radiant temperature. Temperature affects comfort in a number of ways and, in combination with the other parameters described in this section, is a key factor in our energy balance, thermal sensation, comfort, discomfort, and perception of air quality.

Dusting

is the appearance of a powdery material on the surface of a newly hardened concrete slab. An excess of harmful fines (clay or silt) in a concrete mix with the sand and portland cement at the surface can result in dusting. This condition emphasized the need to use clean, well-graded coarse and fine aggregates.

Operative Temperature

is the average of the dry-bulb temperature and the mean radiant temperature (MRT).

Scaling

is the breaking away of the hardened concrete surface of a slab to a depth of about 1/6 to 3/16". It usually occurs at an early age of the slab. Scaling of a slab may occur if it is subjected to cycles of freezing and thawing soon after the slab has been placed.

Workability

is the ease of difficulty of placing concrete in a particular location. A stiff but plastic mix with large aggregate would be workable in a large open form but not in a thin wall with closely spaces reinforcement.

Dampproofing

is usually a bituminous coating applied to prevent materials from absorbing adjacent moisture or to prevent absorbed moisture from penetrating further into an invaded system. Bituminous dampproofing is not appropriate when the adjacent water is under hydrostatic pressure. Bituminous dampproofing may be used either on the interior or exterior but is usually concealed in either case. Interior uses include interior surfaces of exterior above-grade walls; interior surfaces of the exterior wythe of exterior cavity wall; and for coating structural steel subject to high-moisture conditions. Bituminous dampproofing is available in either hot- or cold-applied forms.

Mean Radiant Temperature (MRT)

of surrounding surfaces influence human comfort. With respect to the human body at a particular location, mean radiant temperature is defined as the uniform temperature of an imaginary surrounding enclosure in which radiant transfer from the human body would equal the radiant heat transfer in the actual nonuniform enclosure. MRT is a calculated variable and cannot be directly measured.

Chimney flashing

p. 473-474

Roof penetration flashings

p. 538-539

Gypsum board joint tap and joint compounds

p. 673

Exterior topcoat paints: oleoresionous paints

p. 800

Exterior topcoat paints: Alkali-resistant paints

p. 801

Reintegrating daylighting, passive solar heating, and cooling

p.252-254

masonry cement mortars

(masonry cement, sand, and water) are made using proprietary mortar mixes called masonry cement. Masonry cement manufacturers combine in one bag such ingredients as portland cement, portland blast-furnace slag cement, portland-pozzolan cement, natural cement, and slag cement. Masonry cement may also contain hydrated lime, limestone, chalk, calcareous shell, talc, or slag, and an air-entraining agent or other admixtures. Advantages: readily available, convenient to mix, produces a mortar with generally good workability; but availability will be reduced by the availability of ready-mixed portland cement-lime mortars which resemble ready-mixed concrete in that the ingredients are batched and mixed at a central location, and delivered to a project site ready to use Disadvantage: standard for it ASTM C91 does not limit the ingredients or their proportions, or control the types or quantities of admixtures a producer can include in it. Therefore, the performance of masonry cement is relatively unpredictable when compared with portland cement-lime mortars made in compliance with ASTM C270, which does limit the ingredients and admixtures in mortar.

Finishes applied on stone include the following:

- Chat-sawed surfaces are coarse pebbled surfaces made by using a coarse abrasive during sawing. - A flamed (thermal) finish results from the application of a direct flame at high temperature (with a blow torch). This usually is seen in granites and some limestones. Most stones cannot withstand this treatment. - A hand-tooled surface is any surface made using hand tools. - Stone having honed finish are smooth, like polished ones, but are nonreflective. Honed finishes are achieved by rubbing by hand or machine using abrasives. - A plucked surface has a rough finish made by rough-planing the surface and breaking out (plucking) small particles. -Polished stone has a mirror-like surface. Only crystallized stone can take a polish. Essentially, at a microscopic level, polishing is putting facet on each crystal, much as a jeweler puts a facet on a diamond. The result is a surface that allows light to reflect in and out of the stone in a parallel way, enhancing the visible light and color and giving the appearance of depth. A polished finish does not affect the porosity of the stone. - A rock-face surface is coarse and irregular. It is sawed on the top and bottom, and the face is exposed by splitting and is then dressed by machine. - Rubbed or fine-rubbed finishes are achieved by rubbing with abrasives, such as said or grit. A rubbed finish has occasional light trails or scratches. A fine rubbed finish is smooth but has no sheen. - A rusticated stone face has a deep joint effect cut by machine and sometimes finished by hand. - Sandblasted stone has a smooth mat surface. - A sawcut finish is simply the rough sawcut surface of the stone with no other treatment applied. Sawcut material is seldom used where it will be visible in a completed building, but tumbled marble is often amide from sawcut material; if not tumbled enough, it will show circular saw marks. - A sculptured finish is a reproduction of a sculptor's model carved in the stone by hand. - A split-face finish is a rough, irregular surface made by sawing the stone at the top and bottom and splitting it.

Stone is used in many forms, including the following:

- Fieldstone is regular or irregular stone units that are gathered from stream bed and fields. It is most often used for fences and site walls, for landscaping, and sometimes as riprap. - Rubble is rough-cut or blasted stone used in walls. - Flagstone is think slabs of stone that is used primarily as flooring or paving. - Dimension stone is stone that is cut with square corners. It may be think slabs, large or small blocks, or sculptured shapes. - Cut stone consists of large pieces of dimension stone. - Ashlar is small rectangular blocks of dimension stone. - Crushed stone is made by crushing stone from the quarry. It is used as fill beneath building slabs and paving; drainage fill; riprap; as aggregate in concrete, terrazzo, and asphalt; and in landscaping. - River gravel is relatively small, smooth stone gathered from stream beds. It is used in locations similar to those for crushed stone. - Stone dust results from quarrying, milling, and finishing of stone. It is used as mulch and for other landscaping purposes.

Methods used to control rain and melting snow penetrating into masonry walls include providing:

- adequate flashing - proper tooling of mortar joints - parging and dampproofing - painting - filling joints between masonry and doors, windows, and other openings and penetrations with sealants - a sufficient slope of wash to readily drain horizontal surfaces, such as those at sills and copings - an overhang on sills and copings and the like, include drips to keep rain and melted snow away from the walls - adequate gutters and downspouts

Advances in concrete technology continue at a rapid pace, with the relatively recent development of:

- plastic and metal reusable forms, some that impart textured finishes to concrete - flying forms that permit rapid form erection and removal - advanced chemical formulas for portland cement formulations (high-early strength, air-entrained, etc.) for different uses - admixtures to control the setting time, ease of delivery, and other characteristics of concrete mixes - high-strength steel strands that make prestressing possible - steel and plastic fiber reinforcement that make slab surfaces stronger and reduce the need for joints - strong and light glass-fiber-reinforced concrete building cladding - machine delivery devices such as transit mixing trucks, batch mixing plants, and concrete pumps - machine placing and finishing devices, such as internal and form vibrators, motor-driven screeds, and mechanical riding trowels

Zoning Codes

- promote the general welfare by ensuring adequate light, air, and convenience of access to building - provide for safety from fire, flood, and other dangers - reduce congestion in the public streets - create a convenient, attractive, and harmonious community - expedite adequate police, fire, and rescue protection - expedite emergency evacuation - provide adequate public facilities (schools, parks, playgrounds, etc.) - reduce encroachment on historic areas - protect against overcrowding of land - prevent undue density of population - encourage economic development

Heights of wall switches

48" aff is best, 54" aff max. 36"-40" aff is best, 48" aff max. when wheelchair forward position over the counter

Cavity masonry walls

A cavity offers two advantages in areas of severe exposure. The continuous air space provides insulation to be installed within the wall to further reduce heat transfer. It also acts as a barrier to moisture, eliminating the need for furring, since significant rain penetration to the interior is practically impossible if proper flashing and weep holes are installed. A cavity also may be used to conceal mechanical and electrical utilities.

Wrought steel products

Flat-rolled finished products thicker than sheet and strip, produced from slabs or slab ingots by hot rolling, are called plates. The two principal classes of plates are sheared and universal, depending on the type of mill on which they are rolled. Sheared plate mills have only horizontal rolls and produce plates with uneven edges and end, which must later be flame cut sheared straight to the desire size. Universal plate mills have vertical rolls that are capable of producing smooth, straight edges so that only the ends must be trimmed. Lighter plates may also be rolled on some sheet and strip mills from slabs produced in blooming or slabbing mills.

Expansion anchors Fig. 3.5-4

Heavy duty expansion anchors: A hole is drilled in the concrete after it has set. The anchor is placed in the hole. The bolt furnished with the anchor is passed through the item to be supported and into the anchor shell. As the bolt is tightened, the expanding portion of the anchor is forced apart, wedging the anchor securely into the drilled hole. Light duty expansion anchors: The one shown has a driver pin; others have bolts or screws. They are placed in drilled holes in set concrete. A pin, screw, or bolt is passed through the item to be driven with a hammer. Screws are tightened with a screwdriver, bolts with a wrench. As the pin, screw, or bolt is forced into the anchor, the anchor expands, locking itself into the drilled holes.

Wrought steel products

In close-die forging, a hammer pounds a section of steel between carved dies until it reaches the desired shape.

Wrought steel products

In open-die forging, a large press squeezes (rather than strikes) steel between two flat surfaces.

Ceramic glazing of clay masonry units

In the high-fired process, the glazes are sprayed on the masonry units sometimes before and sometimes after drying. The units are then kiln-fired at normal firing temperatures.

Forming of clay masonry units

In the stiff-mud process, clay is mixed with sufficient water (12%-15% by weight) to produce the desired degree of plasticity. After thorough mixing (pugging), the tempered clay goes through a de-airing machine in which a partial vacuum is maintained. De-airing removes air, thus eliminating holes and bubbles, which improves the clay's plasticity and workability and results in greater strength in finished units. After de-airing, the clay is forced (extruded) through a die, which produces a clay column of the desire shape. Here, various textures may be applied. The column then passes through an automatic cutter. Die sizes and the spacing of cutter wires must be calculated to compensate for normal shrinkage during drying and burning. After they are cut from the column, individual units proceed from the cutting table onto a continuous moving belt, where they are inspected. Acceptable units are removed from the belt as it passes and place on dryer cars. Imperfect units are returned to the pug mill.

Properties of clay masonry units

The durability of clay masonry units is affected by pore size within the units and by the amount and completeness of fusion during burning. In general, higher burning temperatures produce harder clay masonry units. A major weathering action that affects burned clay masonry units is alternate freezing and thawing in the presence of moisture. A second factor that affects the durability of clay masonry units is their soluable salts content.

Forming of clay masonry units

The soft-mud process is used only for producing brick. It is particularly suitable for clays that contain too much natural water (20-30% by weight) to be satisfactorily extruded in the stiff-mud process. In the soft-mud process, raw clay is mixed with water, and the mixture is then formed into units in molds. To prevent this clay from sticking, the molds are lubricated with sand and water or just water.

Portland cement-lime mortars and grouts

To combine the advantages of portland cement and lime and to compensate for their disadvantages, and because their mixture produces the most predictable mortars and grouts, portland cement-lime mortars and grouts (portland cement, lime, and water) are widely used. In portland cement-lime mortar and grout, the portland cement contributes durability, high early strength, a consistent rate of hardening, and high compressive strength. Lime adds workability, water retention, and plasticity. Both contribute bond strength. Sand acts as a filler, making the mix economical, and adds strength. Water is the mixing vehicle. It creates plastic workability and initiates the cementing action.

Clay masonry unit colors and shades

To produce different colors and shades of colors, masonry units are sometimes subjected to reducing atmosphere (one that contains insufficient oxygen for complete combustion) near the end of the burning process. The colors and shades produced by this so-called flashing will vary with the type of clay used in the unit.

Mortar types:

Type M: is a high-strength mortar that has somewhat greater durability than other mortar types. It is specifically recommended for use in reinforced masonry and where high compressive strength is necessary. A typical use is in a reinforced masonry wall that is below grade, such as a foundation or retaining wall. It is also used extensively for walks, sewers, and manholes and to set stone in paving installations. Type S: is a medium-high-strength mortar recommended for use where bond and lateral strengths are more important than high compressive strength. Tensile bond strength between brick and Type S mortar approaches the maximum obtainable with cement-lime mortars. Type S mortar is recommended for use in reinforce masonry and in unreinforced masonry where maximum flexural strength is required. It is also used in setting beds for granite, marble, and slate in other than paving installations. Type N: is a medium-high-strength mortar recommended for general use in exposed masonry above grade where high compressive and lateral strengths are not required. It is specifically recommended for chimneys, parapet walls, and exterior walls subject to severe exposure. It is also used to set limestone other than in paving installations. Type O: is a low-strength mortar suitable only for general interior use in non-load-bearing masonry and for tuck pointing. It should never be used where it will be subjected to freezing conditions.

Sand-lime mortars

harden at a slow, variable rate, develop low compressive strength, and have poor durability when subjected to freezed-thaw cycles. However, sand-lime mortars have high workability and high water retention, and they are more flexible than portland cement mortars. Because lime hardens only when in contact with air, complete hardening of a lime mortar occurs very slowly over a long period of time. This is disadvantage in terms of project progress. The advantage of this slow hardening is that even when cracks occur, they often heal spontaneously during the hardening process, which tends to help keep water penetration to a minimum. Sand-lime mortar is seldom used today except in renovation work where an existing masonry was laid using a similar material.

Portland cement mortars and grouts (portland cement, sand, and water)

harden quickly at a consistent rate and develop high compressive strengths. They also have good durability when subjected to freeze-thaw cycles, but their workability and water retention are low. Portland cement grouts are used in the installation of the kind of architectural terra cotta called ceramic veneer. They may also be used in other types of masonry but are not permitted in engineered unit masonry walls.

Hollow core doors

- Mesh (cellular) core - Ladder core

Interior topcoat paints: gloss finishes

- gloss enamel - floor enamels - alkali-resistant enamels - epoxy and urethane enamels - dry-fallout spray gloss p. 799

Exterior topcoat paints: oil-base paints

- gloss house paints - barn paints p. 800

Sheet metal installation

- joints and edges - expansion and contraction - flashing receivers p. 539-540

Vacuum breaker

A device used in some fixtures to accomplish the same thing as a trap. The attachment is placed on a hose connection valve or toilet/urinal valve to prevent water from being sucked backward into the public water system.

Air-air heat pumps

A single-package air-air heat pump moves heat between an outdoor airstream and an indoor airstream; although kept separate, both streams pass through a single outdoor unit. A system with both outside and inside components is called a split system. A split-system air-air heat pump moves heat via a refrigerant loop between the outdoor unit (which also contains the compressor), through which outdoor air passes, and the indoor unit (which usually contains backup heating coils) for the treatment and circulation of indoor air. Single-package heat pumps are commonly located on roofs, where they have unlimited access to outdoor air and where their noise is less likely to annoy - provided they are sufficient isolated from the building's structure.

Carpet appearance retention: crush resistance

Crush resistance is dependent on the ability of the fibers to recover from short- and long-term compression loads. This property is measured by the extent to which the fiber springs back after a load has been removed as a percentage of the original height.

Control & expansion joints: joints in tile finish

Expansion joints are not required in areas less than 12' wide or over old, well-cured concrete. However, expansion joints should always be provided in a tile finish 1. directly over expansion, isolation, construction, or control joints in the backing, 2. where the tile finish abuts projecting surfaces, and 3. at proper intervals in floor areas measuring over 24' in either direction. Expansion joints in a tile finish should never be narrower than the underlying joint in the backing. Exterior installations should be provided with expansion joints at least 3/8" wide for joints 12' o.c. and at least 1/2" wide for joints 16' o.c. These minimum joint widths should be increased 1/16" for each 15 degrees F of temperature differential (range between summer high and winter low) over 100 degrees F. Decks exposed to the sky in the northern U.S. should have 3/4" wide joints 12' o.c. Thickbed tile installations in interior areas should have expansion joints in the tilework spaced 24' to 36' each way. Joints for interior quarry tile and paver tile should be the same width as the grout joints but not less than 1/4" wide. Joints for ceramic mosaic tile and glazed wall tile should be 1/4" wide but never less than 1/8" wide. Large thin-set installations may benefit from appropriately located expansion joints, but no generalizations can be drawn. Joints always are desirable at offsets and changes in backing construction. Regardless of installation methods, expansion joints should be provided in the tile finish over all underlying structural joints, at the tile perimeter and against any projecting surface.

Built-up membrane roofing - application

Forty-five-degree cant strips and tapered edge strips should be installed where the roofing abuts vertical surfaces and at gravel stops.

Water supply pipe material: galvanized steel

Galvanizing is a process that deposits a coating of zinc on the surface of a steel pipe to protect it against corrosion. Galvanized steel (also called galvanized iron) pipes are low in cost and high in strength. They are resistant to high pressures and to water hammer. Their major disadvantage is that joints are typically threaded, although other methods of joining are sometimes used. Threading the initial installation is laborious, and the need to thread new joints in place makes later tapped-in connections to existing system difficult. Galvanized pipe has a tendency to corrode or form scale on the pipe interior to a degree that depends on local water chemistry. There are three available means of joining galvanized steel pipe: 1. Threaded connections are the most common way of joining galvanized pipe. Generally, the outside of the pipe run is threaded to match a female galvanized steel or malleable cast iron fitting with the desired geometry. The threads should be coated with pipe joints compound or wound with plastic joints tape before the fitting is attached. 2. Unions are a means of jointing galvanized steel pipe that can be disconnected and reconnected at future times, but they are more costly than conventional fittings. A union consists of two union nuts with machined brass mating surfaces, each of which is threaded onto the respective pipe end and a ring nut which is tightened, drawing the two union nuts together. The brass components of unions, however, can cause localized corrosion in steel pipes that restricts flow. 3. Slip couplings are a third type of connector available for galvanized steel pipes. They consist of a sleeve and compression nuts. They sleeved is slipped over the end of one pipe. The two pipes are then aligned, and the sleeve is positioned to cover the joint between them. Compression nuts at each end of the sleeve seal it to the pipes by rubber gaskets. Some type of slip couplings also have a screw connection in the center for easier installation.

GFCI

Ground fault circuit interrupter, a safety device on an outlet that monitors the current going to the load and coming back again. As long as the two are equal, the electricity continues to flow. But if the return current is lower, the GFCI will "trip" or open, interrupting the circuit. It must be placed within 6 feet of sinks, throughout baths, in garages, outdoors, in unfinished basements, and in crawlspaces.

Basecoats

Gypsum neat plaster is suitable for use as a basecoat over metal or gypsum lath, gypsum or clay tile, CMU, and brick of moderate suction. Fibered neat plaster often is used as a scratch coat over metal lath because less plaster is lost as mechanical keys are formed behind the lath. When neat plaster is used as a brown coat, sand usually is added to prevent excessive shrinkage. Wood-fibered plaster may be used over the same bases as neat plaster, but it has greater fire resistance than neat plaster and other sanded basecoat plasters. Ready-mixed plaster with a composition similar to that of gypsum neat plaster or wood-fibered plaster may be applied where those two plaster types are acceptable.

Design strategies for heating: direct gain

In a wall-designed direct-gain space, there are ample thermally massive surfaces (such as concrete slab; concrete block; or brick, quarry, or ceramic tile) that directly receive much of this incoming sun. Such massive surfaces should have at least three times the area of south-facing glass in order to keep the space from overheating in sunny hours. The mass should be thick enough, typically at least 4", to absorb and later reradiate a winter day's dosage of direct sun. Direct gain is popular because of its simplicity and its ample daylight and view to the south. Relative to the other passive solar approaches, it has problems of flare, overheating on sunny days, large radiant heat losses to glass areas by night (and thus a large diurnal difference in interior temperature), and fading of furnishings in direct sunlight. This winter heating approach is well matches with the summer cooling strategy of night ventilation of mass; both systems depend on large of internal exposed thermal mass, so such an investment pays off in both winter and summer.

Bored piles

Include auger cast grout, bored and socketed, bored concrete, drilled caissons, drilled concrete piers and shafts, and drilled micropiles. Conditions that make bored piles advantageous include: cohesive soils, obstructions that can be tolerated with the right size drill, and dense reliable bearing surface.

radiant panels with supplementary air

Large areas of radiant surface can be used to offset large losses of bodily radiant heat, as in the case of large areas of cold glass on a writer day or when users are both scantily clothed and sedentary. In summer, such panels can help offset radiant gain from electric lights or large glass areas. The ceiling is often favored for the panel location, because it is uncluttered by the furniture, tackboards, and other items that cover floors and walls.

Glass surface finishes: Etching

Many different degrees of transparency can be produced in glass by etching. These range from a frosted, almost opaque quality to a semipolished, translucent appearance. Hydrofluoric acid or one of its compounds is used to etch glass, as it is the only chemical that interacts actively with glass. The glass is dipped in the chemical or the chemical is sprayed on; the type of surface produced depends on the composition of the glass, the concentration of fluorides, and time involved. If an etched design is desired, the glass is first painted with a acid-resistant chemical (the resist) to protect the parts of the glass outside the desired pattern. The acid eats away the unpainted surface of the glass, leaving the design.

Carpet yarn dyeing methods: solution dyeing

Many synthetic fibers are colored by a dye or pigment introduced into the liquid chemical from which fibers are extruded. In this method, the dye becomes chemically a part of the fiber; therefore, solution-dyed yarns are generally colorfast and more resistant to discoloration from wet cleaning.

IBC states that hardware height for door pulls, handles, latches, locks, and other operating devices shall be installed at _______″ minimum and _______″ maximum above the finished floor.

Minimum 34 inches and maximum 48 inches above finished floor. Typically, door knobs are located at 38 inches on center above the finished floor. Panic hardware and door pulls are typically located at 42 inches on center above the finished floor.

Concrete and unit masonry walls in sound

Nonporous concrete and masonry walls do not permit sound to pass through them, but rather transmit sound by acting as a diaphragm. In a porous walls, the pore structure is the principal transmission path, particularly at low frequencies. When a porous wall's surface is completely sealed with paint or plaster, transmission loss no longer depends on pore structure but instead is determined by the wright and stiffness of the wall. Therefore, the acoustical performance of a painted or plastered porous wall will be essentially the same as that of a nonporous wall of the same wright and stiffness. There is evidence that hollow units may be better sound insulators than solid units of the same thickness and made with the same aggregate type. A suspected reason is that because the core surfaces are denser than the remainder of the block due to the manufacturing process, a skin effect occurs, producing a greater than expected resistance to sound transmission.

Distance between work surfaces in a one-cook and two-cook kitchen.

One cook: 42 inches. Two cooks: 48 inches. A U-shaped kitchen should have 60 inches between work surfaces.

Cavity behind veneer brick

One-inch minimum used in conjunction with dedicated drainage plane material. Two inches recommended to ensure mortar or other debris does not cause blockage.

Carpet comparative factors: pitch, gauge, and needles

Pitch dictates the number of pile warp yearns (tufts) in a 27" width of carpet and is a measure of the tightness of crosswise construction. In knitted and tufted carpets where no continuous lines are present, gauge describes the actual spacing of tufts across the carpet width, expressed as a fraction such a 1/8", 3/16", or 5/32". In tufted carpets, the term needles often is used instead of gauge to describe the number of tufts per inch across the width.

Carpet yarn dyeing methods: print dyeing

Print dyeing provides good dye penetration and pattern definition in tufted carpet. With possible color variation of up to six colors, print-dyed tufted carpets compare favorably in appearance with Wiltons and Axminsters but are cheaper to produce. The process involves silk-screening plain tufted carpet with a premetalized dye and applying an electromagnetic charge under the carpet that drives the dye deeply into the pile. The final pattern is built up by continuously processing the carpet through a series of troughs, each applying a different color.

Tile setting products

Sand should be clean, free from impurities, and well graded. When fine sand is specified, it should pass through a 16-mesh screen. Hydrated lime is used in portland cement-sand mortar to make it more plastic for application on walls and sometimes on floors. Type S (special) lime should be used to ensure a dimensionally stable mortar bed.

Gypsum board: shadowing

Shadowing is actually a surface discoloration, but it may appear similar to nail popping when viewed at a distance. Shadowing is the result of an accumulation of dust or dirt caused by increased thermal conductivity and moisture condensation over a nail head. It occurs commonly on roof and ceiling assemblies and on exterior wall assemblies that are inadequately insulated, and in regions with great indoor-outdoor temperature variations. Shadowing can be remedied by periodic washing or decorating. It can be avoided by proper insulation design and use of laminated two-ply construction. Where a permanent ventilating system is employed, adequate air filtration and humidity control will be helpful.

Filigree slabs

Slabs combine desirable characteristics of cast-in-place precast concrete. The panels act as permanent forms for the field-placed reinforcing and cast-in-place topping. The underside is smooth and can be left exposed.

Ceramic glazing of clay masonry units

Some glazed colors cannot be produce at high temperatures. When these are desired, low-fired glazing is used. In this process, the glazes are applied after the units have been burned to maturity and cooled. Then the units with the glazes applied are fired again at a lower temperature.

Air handling equipment

Some common fan types include: Panel: the most simple type on this list; for high-efficiency air delivery, the motor is generally mounted in the center of the propellers. It is likely the noisiest type. It is not designed for much static pressure from ductwork, filters, and so on. Fixed pitch vane axial: capable of working against somewhat more static pressure than the panel fan; more common in industrial applications. Centrifugal: with an airfoil bladed wheel, it has high efficiency over a wide operating range and is quieter than the previous two. Major changes in pressure result in only minor changes in the volume of air delivered. Vane axial adjustable pitch: takes less space than centrifugal fans and can work against more static pressure. The pitch is adjustable occasionally, not continuously, for system balancing or seasonal changes in air volume. Vane axial controllable pitch: the automatically controlled pitch responds to changes in temperature, humidity, airflow, and so on, depending on the sensors used. It is commonly used in VAV systems.

Carpet yarn dyeing methods: piece dyeing and resist printing

Some woven and many tufted carpets are piece-dyed by immersing the entire carpet in a hot dye bath. However, the carpet need not be dyed only one color, some synthetic fibers can be chemically formulated to absorb certain compatible dyes and repulse others. Thus it is possible to produce complex color patterns in the same dye bath. A similar technique of selective dyeing can be applied in skein dyeing. Resist printing, another method of selective dyeing, involves printing tufted carpet with a dye-resistant agent before piece dyeing.

Stress

Stress is the intensity of a force. It is force per unit area, or f = P/A, where f is stress, P is force, and A is cross-sectional area. There are two kinds of stresses: normal (perpendicular) and tangential. Shearing stresses are tangential and axial stresses are normal. Bending stresses result in both normal and tangential stresses.

Variable air volume (VAV) system

TA type of Heating, Ventilating, and/or Air-Conditioning (HVAC) system that provides a varying rate of airflow through diffusers in each zone under the control of zone thermostats.

Carpet appearance retention: texture retention

The ability of carpets to retain the surface texture imparted during manufacture is related to the compression and crush resistance of the fibers, as well as the density of the pile and tightness of the yarns.

Vinyl sheet and tile

The chief ingredient of vinyl products is PVC resins. Other ingredients include mineral fillers, pigments, plasticizers, and stabilizers. Plasticizers provide flexibility; stabilizers fix the mixture to ensure color stability and uniformity. Vinyl products sometimes are referred to as flexible vinyl to distinguish them from vinyl composition products, which also are made with PVC resins and are termed semiflexible. The vinyl resins and plasticizers together are called the binder.

Forming of clay masonry units

The dry-press process is used with clay that has very low plasticity. This clay is mixed with a minimum of water (up to 10% by weight) and then formed in steel molds under pressure of between 500 and 1,500 psi.

Sheet metals

The metal materials generally used in flashing for walls and roofs include - aluminum - copper - lead-coated copper - galvanized steel - lead - stainless steel

Peak sun hours

The number of hours per day at an irradiance of 1 kW/sq meter that is equivalent to the total daily insolation energy.

Induction systems

This familiar system's air terminal may be found below windos throughout the US. A high-velocity (and high-pressure), constant-volume fresh air supply is brought to each terminal, where it is forced through an opening in such a way that air already within the room (bypass, or secondary, air) is induced to join the incoming jet of air. A fairly thorough circulation of room air is thus accomplished with only a little centrally treated air. Air then passes over finned tubes for heating or cooling. Thermostats control the unit's output by controlling either the flow of the water or the flow of secondary air.

Measuring airborne sound transmission

To determine the effectiveness of walls and of floor and ceiling assemblies in isolating airborne sound transmission, the transmission loss (TL) of the wall or assembly must be measured. TL is the number of decibels a sound loses while passing through a wall or floor and ceiling assembly when tested in a laboratory in accordance with ASTM International's ASTM E90. In both laboratory and field tests of walls for airborne transmission, the procedure is to generate a steady sound on one side of the wall and measure the sound level in decibels on both sides. The TL of the wall is the measured difference in sound level on the two sides. Therefore, a sound of a given frequency with an intensity level of 70 dB on one side of a wall will have a reduction in intensity to 40 dB on the other wise when the wall has a TL of 30 dB at his frequency. The higher the TL, the more efficient the wall or assembly.

Gypsum board: sound-isolating constructions

Transmission of airborne and structure-borne sound can be reduced in wall and ceiling assemblies by: - eliminating flanking paths - separating the supporting structural construction of each finish surface - resilient mounting of finishes with channels, clips, or sound-deadening board - including sound-absorbing materials in the assembly cavity - increasing the weight of the surface construction

Direct expansion (DX) system

Type of HVAC system that uses a refrigerant vapor expansion/compression cycle to remove sensible/latent heat from the air. Air passes over the evaporator to cool it, and it is then ducted into rooms. DX systems can be packaged or split systems. They typically take up less space and can be used in zones. A direct expansion (DX) air-conditioning system uses a refrigerant vapor expansion/compression (RVEC) cycle to directly cool the supply air to an occupied space. DX systems (both packaged and split) directly cool the air supplied to the building because the evaporator is in direct contact with the air supply.

Vinyl siding instllation

Vinyl siding does not provide a weatherproof barrier. Therefore, a weatherresistant barrier is required beneath vinyl siding, and flashing and other means are required to lead water that enters the siding back to the exterior. Joints should be planned so that, wherever possible, no piece is less than 20" long. Siding overlaps should not be caulked, and siding panels should not be caulked where they meet receivers, corners, of J-trim, but should rather be permitted to flat free to account for expansion and contraction.

Heating/cooling systems

a. Cooling coils added to warm air furnaces b. Hydronic and coils c. Air-air heat pumps d. Ground source heat pumps e. Water source heat pumps

Passive cooling guidelines

a. Cross-ventilation b. Stack Ventilation c. Night ventilation of thermal mass d. Evaporative cooling e. Cooltowers f. Roof ponds g. Earth tubes

Softwoods

are called conifers or coniferous because most species bear cones. With few exceptions, softwoods have scale-like or needle-like leaves and are evergreen.

Splits in wood

are lengthwise grain separations extending through the piece from one surface to the other. They are measured as the penetration of the split from the end of the piece and parallel to the edge of the piece.

Timbers

are lumber pieces 5" or more in the smallest dimension. These may be further classified as beams, stringers, posts, caps, sills, girders, purlins, and other members. Lumber thicker than 5" in either face is seldom used in ordinary construction and, when stocked by retail yard, is frequently in a green, rough (undressed) condition. When heavy timbers are used, shrinkage of the assembly should be expected, and the design of the structure should be planned to minimize the effects of this shrinkage. Laminated timber, made by gluing up smaller pieces that can readily be kiln dried, should be used when seasoned timbers are mandatory.

Welded joints

are made by melting the edges of the components to be jointed and adding filler metal if required. Brazing and soldering generally employ no-ferrous filler metals which have melting points below those of the base metals and do not require melting of the base metal to effect a bond. When the filler metal has a melting point below 800 degrees F, the joining method is considered soldering; if above, it is brazing.

Air infiltration barriers

are membrane sheets and boards with sealed joints, cement parging, and similar products. reduce the number of air changes in a building and help create a more energy-efficient interior environment. They also protect sheathing against deterioration and resist the further penetration of moisture that finds its way through the siding or other finish material. Air infiltration barriers in common use over wood-framed walls today include asphalt saturate organic felt (building paper), polyethylene sheets, and woven polyolefin sheets. Fairly new on the market are spray-applied air barriers.

Expansion bolts

are semipermanent fasteners generally used to join materials to concrete and masonry surfaces. They are referred to as cinch anchors, or expansion anchors, and by many proprietary names. These devices consist of two or more units that develop holding power in concrete or masonry through wedge action and friction with the walls of a pilot hole by expansion. This action is produced by striking or turning the threaded machine bolt insert. Expansion bolts act in a manner similar to that of screws used with lead, fiber, or plastic shields but usually develop much greater withdrawal strengths.

Common grades in wood

are suitable for general construction and utility purposes.

Dimension lumber

as defined in PS 20, is "lumber from 2" to, but including 5" in nominal thickness, and 2" or more in nominal width. Dimension may be classified as framing, joists, planks, rafters, studs, small timbers, etc."

Admixtures

called plasticizers, such as mineral, animal, vegetable, or glass fibers, sometimes are added to a plaster mix to improve its plasticity. These plasticizers can be added to the first (scratch) coat where greater cohesiveness of the mix is required, particularly for ceilings and soffits, and to reduce the amount of mix lost through openings in metal reinforcement when backing paper is not used. Mineral fibers also may be used for machine applied base coats to prevent segregation of the aggregate and to provide lubrication in the hose.

Yard lumber

consists of grades, sizes, and patterns generally intended for ordinary construction and general building purposes.

Detectable warnings

detectable warning surfaces are required on walking surfaces in front of stairs, hazardous vehicle areas and other places where a hazard may exist without a guardrail or other method of warning someone. Such textures must contrast with the surrounding surface. Door handles must be textured if the door leads to an area that might prove dangerous to a blind person (ie. doors to loading platforms, boiler rooms, stages)

Masonry load-bearing walls

in residential buildings three stories or less in height may be 8" thick when not more than 35' high if the roof is designed to impart no horizontal thrust. Except where earthquake design is required, exterior walls in one-story residential buildings may be 6" thick when they are not more than 9' high, the height to the peak of the gable does not exceed 15', and girders and concentrated loads are supported on not less than 8x12" integral piers or pilasters. Interior bearing walls in dwellings not more than one and a half stories or 20' high may be 6" thick. Load-bearing walls more than 35' high should be at least 12" thick for the top 35' of their height, and should increase 4" in thickness for each successive 35'. Cavity walls built of solid masonry units and more than 25' high above the support of the wall may be 10" thick. The facing and backing of cavity walls should each be at least 4" thick, and the cavity should not be less than 2" or more than 4.5" wide.

Flexible sheet flashings

include elastic sheet materials made from PVC or modified polymers and membranes composed of glass fiber or organic felt fabrics saturated with bitumen. These are used as damp checks and as low-cost substitutes for metal flashing at wall bases, open heads, window sills, floor lines, and in other locations where wall flashings are needed. Elastic sheet materials are also used in conjunction with single-ply roofing and as base flashings and penetration flashings in some types of built-up bituminous roofing. Elastomeric sheets, usually plain or reinforced chlorinated plyethylene, are used as roof expansion joint covers. Often this joint covering is bonded to a layer of foam insulation.

Lock-seam joining

is a mechanical method of joining sheet metals in both shop and field by bending and interlocking the elements.

Gypsum board: Strip reinforcing

is a method of reinforcing joints against ridging that offers many of the advantages of two-ply construction at reduced cost. By combining adhesive lamination with mechanical fastening, the number of nails in the face ply is reduced. Although it results in thicker assemblies than back blocking, strip reinforcing can achieve the same results in possibly less time. p.682-683

Seam welding

is actually a series of overlapping spot welds produced under pressure by a pair of disc electrodes, as in welded pipe manufacture.

Projection welding

is also similar to spot welding but makes use of preapplied projective embossments on one of the components to localize the heat and effect of a weld in the desired spot.

The hot-rolled mill finish (black, as-rolled finish) on carbon steel

is characterized by a mill scale and rust powder, which is sometimes acceptable as a base for organic coatings applied by brush. For spray painting, this rust powder must be removed by sandblasting or wire brushing.

Wet-bulb (WB) Temperature

is measured by a thermometer with a wetted bulb rotated rapidly in the air to cause evaporation of its moisture. In dry air the moisture readily evaporates and draws heat out of the thermometer to produce a lower temperature reading, called the wet-bulb depression (the difference between DB and WB temperatures). A large depression is indicative of low relative humidity (RH). Slow evaporation, as when the air is already moisture-laden, results in a small wet-bulb depression and indicated high RH.

Plastic concrete

is one that is readily molded and yet will change its form only slowly if the mold is removed.

Crazing

is the occurrence of numerous fine hair cracks in the surface of a newly hardened slab due to surface shrinkage. Crazing can be the result of rapid surface drying usually caused by either high air temperatures, hot sun, or drying winds or a combination of these. It can be lessened by curing with water, because water will maintain or lower the concrete surface temperature. Premature floating and troweling when there is an excess amount of moisture at the surface, or whole the concrete is still too plastic, brings an excess amount of fines and moisture to the surface. Rapid loss of this moisture will cause shrinkage at the surface, which may result in crazing.

Acoustical correction

is the physical shaping of a space to produce the best possible hearing conditions. The objective is to shape an environment where sounds are heard distinctly, in ample loudness, and with as faithful a replication of the source as possible everywhere in the space.

Noise reduction

is the treatment of interior surfaces with acoustical materials to alleviate the discomfort and distraction caused by the reflection of unwanted sound.

Form decking

is used as a permanent form for a concrete slab. It varies in thickness from 1/2" to 2". Spans range from 1 to 2 ft for light 1/2" form decking to as much as 12 ft for heavy 2"-thick decking with 6" rib spacings.

Calculating worst-hourly heat loss

p.254-256

Calculations for heating season fuel consumption (conventional buildings)

p.256-259

Passive cooling calculation procedures

p.287-314

Decorative glass

p.627

Portland cement curing

p.664-665

Gypsum board: moisture-resistant construction

p.685-686

Electric traction elevators

p.892-893

Inground oil hydraulic elevators

p.894-895

MRL elevators

p.895

Thermal insulation materials

pgs. 444-447