Lecture 19

Question 1

Two things to be considered for exterior envelope (food and walls)

Answer 1

Thermal aspects

Water

Question 2

Purpose of thermal insulation

Answer 2

To slow the conduction of heat

Question 3

Thermal resistance

Answer 3

Material effectiveness in resisting the conduction of heat

Question 4

R-value

Answer 4

Thermal resistance

Question 5

Higher R-value=

Answer 5

Higher resistance

Question 6

Thermal performance of a building=

Answer 6

The sum of thermal resistances from all materials

Question 7

Thermal bridging

Answer 7

Low thermal resistance penetrates the thermal barrier

Question 8

Thermal bridging is reported by detailing _____

Answer 8

Thermal breaks

Question 9

Dew point

Answer 9

When air cools bring in grow relative humidity to 100%

Question 10

Humid rooms have a _____ dew point

Answer 10

Higher

Question 11

More water vapor in an air mass= ________ vapor pressure

Answer 11

Greater

Question 12

When air inside is warmer than air outside the vapor pressure moves

Answer 12

Outwards

Question 13

Vapor retarder

Answer 13

Sheets of water resistant material to diffuse vapor

Question 14

Vapor retarder is located on the ______ side of the building assembly

Answer 14

Warmer

Question 15

Is a vapor retarder always necessary?

Answer 15

No

Question 16

Opposite and cooler side of assembly from the vapor retarder must be “________”

Answer 16

Breathable

Designed so that any moisture that does pass can be turned to vapor

Question 17

Why should multiple vapor-impermeable layers be avoided

Answer 17

They can trap moisture

Question 18

Why are roofs more important to thermal performance than walls

Answer 18

Heat rises

Question 19

Two roof categories

Answer 19

Low-slope roofs

Steep roofs

Question 20

Pros of steep roofs

Answer 20

Drain quickly

Easy to repair

Question 21

Minimum slope for drainage of a “flat roof”

Answer 21

1/4” per foot OR 2% slope

Question 22

Most primary function of enclosure

Answer 22

Keep water out

Question 23

Pressure equalized wall design

Answer 23

Wind pressures inside and outside neutralize themselves

Question 24

Rainscreen

Answer 24

Protects the air barrier from exposure to the outdoors

Question 25

Pressure equalization chamber (PEC) is locates between

Answer 25

The rainscreen and airbarrier

Question 26

Purpose of sealant joints

Answer 26

Prevent water and air from flowing through wall components while allowing for movement

Question 27

High range sealants can elongate up to ________%

Answer 27

50-100%

Question 28

Low range sealants (caulks) can stretch up to ______%

Answer 28

5%

Question 29

Gaskets

Answer 29

Strips of rubber like materials for sealants

Question 30

3 reasons Aluminum is the metal of choice for metal cladding

Answer 30

Protects from corrosion
Attractive finishes
Can be affordably extruded into many shapes

Question 31

Why does aluminum require thermal breaks

Answer 31

Aluminum conducts heat very rapidly

Question 32

Why is aluminum usually treated

Answer 32

To provide control of appearance from film that protects from corrosion (has a chalky appearance)

Question 33

Anodizing for aluminum

Answer 33

Crates an oxide layer thicker than the natural film

Question 34

How is aluminum anodized

Answer 34

Acid baths

Question 35

Stick systems pros

Answer 35

Low shipping bulk

Very adjustable

Question 36

Stick system con

Answer 36

Must be assembled on site

Question 37

Unit system

Answer 37

Assembled in factory

Question 38

Pro of outside glazing

Answer 38

Simple shapes= less expensive

Question 39

Pros of inside glazing

Answer 39

Convenient to install in tall buildings

Question 40

Why must cladding have expansion joints

Answer 40

Because cladding is exposed to temperature fluctuations and aluminum has a high coefficient of thermal expansion