Chapter 12

drainage systems fall into two types: aboveground and underground

1.Aboveground drainage systems use pervious paving, sheet flow, gutters built into roadways and parking areas, ground swales as part of the landscaping, and channels to manage runoff and direct it appropriately. 2.Underground drainage .rystems use perforated drains and enclosed storm sewers to carry the runoff from the site, either to a municipal storm sewer system or to a natural drainage outlet such as a river. Several methods of drainage may be combined in a single project.

Some other methods of controlling site noise are as follows:

1.Maximize the distance between the source of the noise and the receiver 2.Avoid hard surfaces near the source of noise. Hard surfaces reflect sound and help it travel. 3.Avoid parallel hard surfaces. They can intensify the noise. Where possible, orient buildings, walls, and other hard surfaces at angles from one another. 4.Plant evergreen trees and shrubs densely between the noise source and the receiver. 5.Control sources of noise that are in or near the building 6.Make use of masking sounds 7.Design building features to block noise

reflective roofing/cool roof

A cool roof is a roof covered with a light-colored material that reflects more of the sun's heat than it absorbs. Generally, a roof must have a minimum reflectivity of 0.65 when new and a three-year aged value of at least 0.50 to be considered a cool roof according to the EPA's Energy Star cool roofing requirement. Buildings with cool roofs have been shown to have lower cooling needs, thus reducing energy use, as well as to help reduce the heat island effect in urban areas.

Underground systems use piping with a minimum slope of 0.3%. Storm drains collect water from roof downspouts, drain inlets, catch basins, and drain tiles surrounding the building foundation

A drain inlet is an opening in the ground that allows stormwater to run directly into the storm sewer; the opening is usually covered with a metal grate for safety and to keep out debris

parking access aisle

A percentage of the accessible spaces may be required to be van accessible; for a van-accessible space, the adjacent access aisle must be 96 in wide and level with the accessible route. A maximum slope of 2% must be maintained.

The minimum slope of the building sewer is 0.5% to 2.0% depending on the size of the pipe. A greater slope is required for smaller pipes

A pipe with a diameter of 2 1/2 in or less must be placed at a slope of 1/4 in/ ft, a pipe with a diameter of 3 in to 6 in must be placed at a slope of 1/8 in/ ft, and a pipe with a diameter of 8 in or more must be placed at a slope of 1/16 in/ ft.

crown

A road should have a gradual cross slope for drainage from the center of the roadway, called the crown, to the sides. This slope should be a minimum of 1/4 in/ ft. If the road has a gutter, the edge of the gutter should be 6 in high

drive aisles or access aisles,

A single-loaded aisle has spaces on only one side; a double-loaded aisle has spaces on both sides.

When the stormwater management strategy includes surface drainage, minimum slopes are needed to provide positive drainage.

Although the table indicates that a slope as little as 0.5% may be sufficient for some drainage, this is true only for very smooth, carefully constructed surfaces. For most paved surfaces, a slope of at least 1 .5% is needed to account for paving roughness and variations in installation tolerances.

internal-load dominated building is one whose energy use is driven by high heat gain from occupants, lighting, and equipment

Buildings of this type include office buildings, hospitals, retail stores, schools, and laboratories

sight security

Design for site security can be accomplished by viewing the site at four different levels. 1.perimeter protection 2.access and parking 3.on-site security 4.building envelope protection

Wind power offers an extremely sustainable method of generating electricity from a renewable and free source.

Even where a wind-driven generating system can be installed, in most cases the electricity must be used as it is generated. Using wind energy to charge batteries has limited use for most building sites. However, some power companies will purchase excess electricity that is generated on private sites, when the electricity is transferred to the utility power grid

collector may be either a flat-plate collector or a focusing collector

Flat-plate collectors consist of a network of pipes located on an absorptive black surface with low emissivity, placed below a covering of glass or plastic. The pipes carry the heat transfer medium, which is usually water with antifreeze but can also be another liquid or air. Focusing collectors are parabolic reflectors that focus the incoming radiation to a single pipe that carries the heat-transfer medium. Because the reflectors direct the sun's energy to a specific point, focusing collectors operate at a much higher temperature than flat-plate collectors.

One useful way to check new contour lines . quickly during design is to use an estimate of the change in elevation from one side of a double-loaded parking area to the other (62 ft).

For a minimum slope of 1 .5%, this change in elevation is about 1 ft. With a maximum slope of 5%, the maximum change in elevation across the same 62 ft parking row is about 3 ft

In most cases, the shape of an internal-load dominated building has less of an effect on energy efficiency than it does for an external load dominated building, unless the building shape is designed to allow extensive use of daylighting or other passive or active energy conservation techniques.

For cool and cold regions, a cubic shape generally works best because the extremes of winter temperature suggest that the surface area should be minimized in both types of load dominated buildings. For the same floor area, a two-story house is better than a one-story house. For temperate climates, building shape has less of cool temperate an effect. However, a building elongated in the east-west direction still offers some advantages hot-arid for winter solar heat gain, daylighting, and minimizing heat gain in the summer. For hot-arid regions, squarer shapes are better. For external-load dominated buildings, the plan should include open courtyards; for internal-load dominated buildings, a solid, multistory arrangement works best. For hot-humid regions, shapes elongated in the east-west direction are preferable to allow breezes, provide natural cooling, and minimize severe heat gain from the east and west directions. Courtyards and broad overhangs are also useful.

azimuth is the compass orientation of the sun

For solar design purposes, this is usually the number of degrees either east or west of due south. For example, if the sun is halfway between south and west, the azimuth is 45° west of south. Sometimes, the azimuth is measured in a 360° circle with due north at 0°, due east at 90°, south at 180°, and west at 270°.

Geothermal energy uses ground-source heat pumps (GSHPs).

GSHPs are electrically powered systems that work like air-source heat pumps by either extracting heat from the ground in winter or giving off excess heat to the ground in summer. Within a GSHP, the heat from the ground is increased through a vapor compressor refrigeration cycle.

The architect should determine the locations of existing utilities before beginning design, and should contact the utility companies early in the design process to confirm their requirements for providing service to the proposed building. These utilities may include sanitary sewers, storm sewers, water lines, natural gas, electricity, steam, telephone, internet, cable television, and others.

If possible, the building should be located so as to minimize the length of utility lines between the structure and the main line. If the existing utility mains are not convenient to the site, it will be necessary to coordinate with the utility companies to determine how the utilities will reach the structure, and to establish the associated costs so that these expenses can be included in the project budget.

rectilinear projection

In this kind of chart, the solar azimuth is plotted along the horizontal axis, and the solar altitude is found along the vertical axis. Several lines represent the sun at yearly time intervals (usually the 21 st day of each month).

Glazing has long been a weak point in constructing energy-efficient buildings. For a long time, designers looking for a more energy-saving alternative to float glass were limited to double-paned glass, tinted glass, reflective glass, and a few other types

Insulating glass (also called double glazing or double-pam glass, or triple glazing or triple-pane glass when three panes are used) is used to control heat loss. This is a glazing assembly in which two or three panes of glass are separated by sealed air spaces or partially evacuated spaces that act as insulators. U-values for insulated glazing decrease to about 0.57 Btu/ft2-hr-°F, assuming two panes separated by a I/4 in air space. However, air currents within the air space still allow heat loss by convection. In addition, some of the desired solar heat gain admitted through the glass is lost by radiation, as objects in the building get warm and begin to emit infrared radiation that passes back outside.

air barrier

It consists of materials, components, and assemblies on all vertical and horizontal surfaces exposed to the exterior. An effective air barrier can reduce energy consumption and help keep out pollutants and excess moisture. Some air barriers are made from vapor-impermeable material. A vapor-i11tpmneable banier acts as both an air barrier and a vapor retarder in the same material. Vapor transmission can be caused by diffusion through materials

To optimize daylighting, the building or building portion should be long and narrow, with the long dimension running east west.

Surfaces on the exterior of the building should be light in color to reflect more daylight. The building should have ceilings as high as the budget allows; high ceilings increase the penetration of daylight into the interior and make it easier to incorporate light shelves into the design

Geothem1al energy draws on heat sources within the earth

The earth absorbs and holds solar radiation within its great mass, keeping the temperature underground relatively constant year round. In the winter, when the air temperature is colder than the underground temperature, a geothermal system uses the heat in the ground to warm an embedded piping system, transferring the heat to the heating system. In the summer, the underground piping system releases excess heat from the air into the cooler ground. The water is cooled and is used to cool the air in the building.

Window Design

The effective aperture (EA) is the product of two variables: visible light transmittance and window-to-wall ratio. The visible light transmittance (VLT) is the percentage of visible light that passes through a glazing material. The window-to-wall ratio (WWR) is the net glazing area in a room or space divided by the gross exterior wall area. It does not include window frames or mullions.

Low-e glass, also known as low-emissivity glass or llow-e glass, is double glazing that includes a thin f1l.m or coating placed somewhere in the glazing cavity.

The film or coating allows both visible and near-infrared radiation to be transmitted through the glass. However, as objects in the room are heated and emit longwave radiation, the f1l.m or coating prevents the loss of this heat; instead, the heat is reflected back into the room.

Sanitary sewers and storm sewers usually take precedence in planning because they depend on gravity flow

The invert, or lowest, elevations of the existing public sewer line should be established, because the effluent must flow from the lowest point where the sewer line leaves the building to the main sewer.

the declination angle

The north-south axis of the earth is tilted at an angle of 23.4° relative to the north-south axis of the sun. This is called the declination angle of the earth and remains constant as the earth revolves around the sun during a one-year period

Parking should be planned so rhat it is efficient, convenient to the building, and separate from pedestrian circulation

The parking capacity is determined by the requirements of the zoning ordinance or by the building program.

runoff coefficient

The required capacity of a drainage system is based on the size of the area to be drained and the amount of water to be drained during the most severe storm anticipated by the design.

Drainage in parking areas should be established as part of the site design

The slope should be between 1 .5% and 5%, but for convenience in calculating, 2% or 3% can be used when figuring the slope of parking lots. Water should drain toward the edges of the parking area where it can run off into the landscaping or be collected and diverted to storm sewers, holding ponds, or other natural or engineered water courses. If curbs are used, there must be some way for the water to drain out, either through curb cutouts or through drains connected to the storm sewer.

parking space

The standard size of a parking space is 9 ft 0 in wide and 19 ft 0 in long for standard size cars, and 7 ft 6 in wide and 1 5 ft 0 in long for compact cars.

During the winter months, the earth's northern pole is tilted away from the sun, decreasing the sun's angle relative to the horizon and reducing the amount of solar energy striking the earth.

The times of maximum tilt in relation to the sun are approximately December 21 for the winter solstice and June 21 for the summer solstice. On about March 21 and September 2 1 , the earth is tilted sideways in relation to the sun, and day and night are of equal length; these are the spring equinox and fall equinox, respectively.

Photovoltaics i s the direct conversion of sunlight into electricity

There are also concentrator systems that focus sunlight on the PV cells to increase energy production, but these are generally limited to use in large-scale power generation. The PV cells convert the sunlight into direct current electricity, which is then converted into alternating current electricity. The electricity can be used immediately, stored in batteries, or sold back to the power utility if the system is connected to the power grid.

sound barriers

These can be thin wall barriers constructed of wood or concrete blocks, or earth berms. A barrier does not completely stop sound transmission; sound will travel over and around it through diffraction, which is the bending of sound waves (or other kinds of waves) around the edge of a barrier or through a small opening

The size and slope of the sewer piping will depend on the capacity needed to service the building.

This portion of the horizontal piping of the sanitary sewer system outside the building is known as the building sewer. The actual connection of the building sewer to the main line must be at an elevation above the invert of the main line at any given point in order not to interfere with the free flow through the main line.

Tinted glass, reflective glass, and heat-absorbing glass have long been used to reduce solar heat gain. However, because about half the incident solar radiation on glass is in the visible spectrum and about half is in the infrared spectrum, tinted glass and reflective glass also reduce the visible light transmittance

This reduces or eliminates the potential for using daylighting to conserve energy; it also generally makes both views out and interiors seem darker, especially on cloudy days. These glass types also eliminate the possibility of making use of solar heat gain when it is desirable.

curb cutouts

When a ramp and an adjacent stairway serve the same areas, both the bottoms and the tops of the ramp and the stairway should be adjacent if possible. As with walks, stairways and ramps should be illuminated

Solar altitude

a different sun chart could be plotted for every fraction of a degree of latitude. In practice, sun charts are usually plotted for every 2°, 5°, or 10° of latitude, depending on what level of accuracy is needed. Data for dates and latirudes between the plotted lines can be interpolated.

Service access

and automobile circulation should be kept separate whenever possible. Service access is typically related to some space in the building program, such as a loading dock, receiving area, or storage area; although service trucks and automobiles may use the same entry and drives if necessary, this service area should be kept apart from automobile circulation.

altitude

apparent height of the sun measured as an angle from the horizon. The horizon is at 0°; directly overhead is 90°.

storage devices

are water for water systems and rock beds for air systems. Phase change maten·als can also be used, but they are more expensive.Distribution components are the same as for standard HVAC systems: ducts for air, pipes for water, and associated fans, pumps, registers, and control devices. When solar energy is used for water heating, the system may be either open loop or closed loop. In an open-loop system, the water is heated directly in the solar collector. In a closed-loop .system, antifreeze or some other transfer medium is heated in the collector and circulated to a heat exchanger, where the domestic water is heated by the transfer medium. This allows use of a nontoxic chemical that facilitates the heat transfer but guarantees that it will be kept separate from the domestic water supply.

passive solar energy system

collects, stores, and distributes solar energy without the use of mechanical equipment. Direct gain systems collect heat through south facing glass and then store this heat in high mass materials such as concrete floors, masonry walls, tile, stone, and terrazzo. During nighttime hours, the high-mass materials slowly release the heat they captured during the day. To make this system effective, the glass area must be well insulated at night or the glazing must be low emissivity glass (also called low-e) glass. Glazing used for passive solar heating should have a U-factor of less than 0.35 Btu/ft2-hr-0F.

automobile circulation

includes locating the entry drives to the site and providing on-site roads to reach the parking areas and the building drop-off point. The entire automobile circulation system should provide direct, easy access to the parking areas and building without excessive drives, turnarounds, dead ends, or conflicts with service areas and pedestrian circulation.

flood test

is a common way to verify watertightness. The area is flooded with 2 in of water for 48 hours, and the interior of the building is inspected for leaks.

Permeance

is a measure of how readily a material or membrane allows water vapor to pass through it. The unit of permeance is the perm, which is one grain of moisture per hour per square foot per inch of mercury difference in vapor pressure (1 perm = 1 g/hr-ft2-in Hg).

catch basin

is an underground reservoir that has a sump built into it; debris settles into the sump instead of flowing down the sewer and potentially clogging the pipes.

external-load dominated building

is one whose energy use is determined mainly by the amount of heat loss or gain through its exterior envelope. Buildings of this type generally have few occupants per unit area and a small amount of heat gain from lighting, equipment, and people. Examples are houses, apartments, condominiums, and warehouses.

Sheet flow

is water that drains across a sloping surface, whether that surface is paved, grassy, or otherwise landscaped. Inmost cases, sheet flow is directed to gutters or channels, which empty into a natural watercourse or storm sewer. Gutters are often used because they can be built along with the roadway or parking area and naturally follow the same slope as the paved surface. They can easily drain into sewers, which also typically follow the paths of roads

holding pond

may be constructed on the site. The holding pond collects the site runoff and releases it into the sewer system at a controlled rate; it also prevents excess water from flooding other areas.

Large storm sewer systems

must have manholes for service access; these are located wherever the sewer changes direction, or a maximum of 500 ft apart. Storm sewers are always completely separate from sanitary sewer systems.

90° parking

parking spaces are perpendicular to the aisle, is the most efficient in terms of land use. However, angled parking is easier to use, forces a one-way circulation pattern, and requires less total width for either a single-loaded or double-loaded layout.

Pedestrian circulation

routes should provide convenient, direct access from the various points on the site, including parking areas, to the building entrances. If connections with adjacent buildings, public sidewalks, public transportation stops, and other off-site points are needed, the circulation system must take these into account as well

infiltration and exfiltration

the movement of air into and out of a building by natural means rather than through mechanical ventilation. Infiltration and exfiltration are caused by differences in pressure between the indoor and outdoor air. These differences can be caused by a combination of wind, the stack effect, the mechanical system in the building, and other factors

Active solar energy rystems

use pumps, fans, ducts, pipes, and other mechanical equipment to collect, store, and distribute solar energy. In order of most common use, active solar systems are used for domestic and process water beating, space beating, space cooling, and electricity generation. A typical active solar system requires three components: a collector, a storage device, and a distribution system

standoff distance

various physical elements can be used including walls, changes of elevation, bollards, dry moats, water features, landscaping, and hardened street furniture. These elements can be used in combination to lessen their visual impact, and they can be combined with fences if individuals must be prevented from entering the site as well.

n-year storm

where the value of n is based on the probability that a storm of this magnitude or greater will occur at this location in any given year. For example, a 100-year storm for a given location is a storm of such magnitude that there is only a 1 % probability that a storm at least as large will occur in any given year. A 25-year storm has a 4% probability, and a 10-year storm has a 10% probability