midterm + final

minimum slope for low slope drainage?

.25"

best way to insulate mass wall

1"-2" spray foam, 2nd best way rigid insulation + fluid applied membrane behind it

In the article "rain control in buildings" john straub lists an approach to rain control that he calls the three D's.

1. Drainage 2. Drying 3. Deflection

name two forces that drive air-flow across the building enclosure (air leakage, infiltration, and or exfiltration)

1. High/low pressure areas 2. wind-physically moving air (mechanical)

what are the top three sources of oregon's electricity power generation?

1. Hydro-electric 2. Coal 3. Natural gas

In the article "air flow control in buildings" john straub lists three primary reasons why the control of air flow is important to building performance. List the three

1. feeling/comfort 2. moisture control 3. thermal control

Rank the vapor permeability of the following materials from least permeable (1) to most (3)

1. foil faced rigid insulation board, 2. kraft paper-faced batt insulation 3. Building wrap (spun-bonded polyolefin)

name stabilization wedges for each of the 3 categories

1. use more efficient appliances/fixtures in the building 2. use of PV 3. forestry

r-value comparisons

2 x 6 @ 16" OC metal studs 8.8 64% , wood studs 16.2 82%

for batt insulation in the framing cavities of a wood stud wall, approximately what percentage of the R-value is lost due to thermal bridging of the framing?

20%

low slope roof =

2:12

approximately what percentage of the total US energy use is associated with the building sector?

50%

What is the percentage of building electricity use?

75% building operations

In what climate is a vapor barrier the most critical?

COLD

does cold air or hot air have a higher capacity for containing water vapor in the air?

HOT AIR

according to the article, "insight: energy flow across enclosures" increasing amounts of insulation and more airtight enclosures reduce energy flow, but this is not always a good thing. Describe why in one to three sentences.

If moisture gets into the enclosure there is no heat exchange or drying capabilities because of the amount of insulation and air tightness. The air tightness doesn't allow for air movement to dry and the insulation traps the heat outside of the enclosure system so there isn't enough heat to dry

continuity can be challenging for air control assemblies when installed at the interior of buildings. Name one common element that can pose this problem

Installation of electrical outlets within the wall system

why is vinyl wallpaper a big problem for air conditioned buildings in hot and humid climates?

It is a vapor barrier and the warm air outside condenses at that point in the interior of space and get's trapped because it's unable to dry.

for theoretical performance, where should the air control layer be located relative to the other control layers?

On the outside

which of the five control layers is most affected by small gaps or leaks?

air control layer

more water gets through vapor diffusion or air leakage?

air leakage

three conditions for water to penetrate a wall

air movement, hole in the control layers, vapor within the wall. (water, hole, driving force)

sealants are commonly used in building enclosures to provide a water barrier, for aesthetic purposes and a number of other functions. Name one

air seals around window assemblies

advantages / disadvantages of curtain wall

bypass floor slab, thermally broken, supports itself, two lines of defense, larger spans, greater water penetration resistance allows for air barrier continuity into the glazing pockets --- construction cost, expensive

advantage of storefront walls / disadvantage

cheaper / low performance, only one defense and leaks a lot

In addition to the energy and comfort aspects of heat loss, what other issue is caused by thermal bridging?

condensation

name 2 sources of exterior loads and one interior

exterior: wind and rain, interior inhabitants (thermal/moisture loads)

because all three conditions must be met simultaneously, exterior walls seldom leak, true or false

false

desired properties of a roof insulation,

fire resistance, moisture resistance, thermal resistance, stable r value, adhesive compatibility , compressive strength

vapor barriers for slow slope roof

fluid applied asphalt sheet, torched down, self adhered membrane, modified bitumen,

five driving forces?

gravity, air currents, surface tension, capillary suction, kinetic energy, pressure difference

air pressure difference in part due to wind currents, is one of the forces that move water through wall openings. Four others were mentioned by Ariel and are also listed in fundamentals. List three of them:

gravity, capillary suction, air currents, surface tension, kinetic energy, pressure difference

movement of vapor goes from...

higher concentration to lower concentration

three fundamental wall strategies for managing water

historical: mass wall, modern approach: perfect wall , recommended modern approach: drained-screen (cavity drainage)

interior loads

humans, pets, equipment, vegetation,

sealants are best applied at temperatures that are neither excessively hot nor excessively cold. why?

if it is too hot the sealants won't solidify and dry, will instead become more fluid. If it is too cold then the air can not hold enough moisture to allow for the sealant to release all of its moisture and dry

In the article why energy matters, john straub references several studies that show

in nearly all cases "operational building use" is more than "embodied energy" of materials

briefly describe three fundamental roles of the building enclosure

keep weather outside, provide thermal comfort, allow for views

in "fundamentals of building construction" chapter 1 & 19, list three performance categories that are not part of the five critical control layers

latent heat control, light controls, acoustics, fire proofing, seismic

vapor barrier vs. vapor retarder

lo-perm vs hi-perm

materials with higher r values

look in the lecture polycarbonate, polystyrene, mineral wool,

bad r values

metal studs,

material for fireproofing

mineral wool

4 things to avoid with vapor barriers

no double vapor barriers, no vinyl wallpaper, don't use vapor barriers when vapor retarders are satisfactory, avoid using impermeable vapor barriers on the inside

where do you want the sealant of a window

on the inside, pressure equalized chamber created below to create cavity that acts as a rain screen

what is the idea location for the control layers?

outside of the structure assembly

what is a curtain wall

panelized structural system that supports itself

thermal heat transfer occurs in what 3 ways?

radiation, convection, conduction

low slope roof thermal layers

rigid insulation, extruded polystyrene,

low slope roof material?

roof deck, thermal insulation,

types of mass wall systems

rubble, solid masonry, composite rubble

which of the following are a part of the building enclosure?

slab on grade floor system, foundation wall system, windows and doors, above grade exterior wall system, roof systems

name three building enclosures examples of thermal briding

slab, studs, furring( metal)

top three energy uses in buildings

space heating 25%, lighting 10%, refrigeration 10%

roof decks

steel concrete wood

difference between storefront and curtain wall

storefront wall, non-structural has to be supported and hangs in place, curtain wall can structurally hold itself

perfect barrier wall systems

structural glazing, steel clad foam panels, face-sealed eifs

what are the five exterior loads

temperature, precipitation, humidity, solar effects and noise/acoustics

what implications do constructability and durability have on the location of the air barrier?

the air control layer would be on the outside of the structure to allow for modifications of the interior walls without harming the control layer, positioned for ease of construction, not exposed to exterior or interior for protection from UV. consistently supported surface such as sheathing

r-value =

the numerical measurement of resistance to the flow of heat

what is the dew point

the point in the wall where water condenses

how are the perfect wall, perfect roof and perfect slab similar?

they all have the configuration of control layers on the exterior of the structure

u-value =

transfer of heat

what is insulated glass

two glass assemblies put together with gas in between

what is a window wall

vast spans of glazing, offers less design flexibility, reliance on members for air and water protection, less allowance for concrete tension,

where do you want the dew point?

warm side of vapor barrier

what are the control layers and primary components of the assembly?

water shedding surface- cladding water resistant barrier - tyvek thermal control layer - insulation vapor control layer -vapor permeable substance air control layer - exterior applied latex sealent

which of the following aspects of performance are (typically) relevant to the building enclosure?

weather protection, durability, longevity, occupant comfort and well being, energy use

briefly explain your answer regarding the location of the control layers:

with all the assemblies on the exterior of the structure prevents thermal bridging, air barrier would not be affected by interior wall modifications, vapor control layer on the exterior would keep the structure moisture free

connection of roof decking systems

wood-mechanically fasten, steel-mechanically fasten, torch down, adhere? concrete