Question 1

The greater is the thickness of a given material, the greater is its perm rating.

Accepted Answer

A) True 
 B)False

Question 2

A membrane air barrier is

Accepted Answer

A) factory- adhered to sheathing panels. 
B) adhered to sheathing on site. 
C) fastened to sheathing on site. 
D) any one of the above.

Question 3

In a building enclosure, such as a room, the air and water vapor are thoroughly mixed together. In terms of their diffusion (transmission)through the enclosure surfaces, do they behave as one gas? Explain.

Accepted Answer

The answer of In a building enclosure, such as a...

Question 4

In addition to being a barrier to the passage of air, an air barrier must also function as a barrier to the passage of

Accepted Answer

A) subsoil water. 
B) both noise and water vapor. 
C) water vapor. 
D) noise. 
E) rainwater.

Question 5

Explain why it is much easier for vapor to flow through building assemblies than air.

Accepted Answer

The answer of Explain why it is much easier for...

Question 6

What are the advantages of attic ventilation in cold climates?

Accepted Answer

The answer of What are the advantages of attic ventilation...

Question 7

Explain how inside- outside air temperature difference affects air leakage in a building.

Accepted Answer

The answer of Explain how inside- outside air temperature difference...

Question 8

Concealed condensation occurs inside an envelope assembly during a heating season if

Accepted Answer

A) the R- value of the assembly is high. 
B) the R- value of the assembly is low. 
C) the interior vapor can permeate into the assembly but cannot exit it. 
D) A and B. 
E) A and C.

Question 9

What is the function of an air barrier and what is it made of?

Accepted Answer

The answer of What is the function of an air...

Question 10

What is concealed condensation and how does it differ from surface condensation?

Accepted Answer

The answer of What is concealed condensation and how does...

Question 11

In hot, humid climates, the vapor flow in conditioned buildings is generally from

Accepted Answer

A) the inside to the outside of the envelope. 
B) the outside to the inside of the envelope.

Question 12

The vapor pressure (VP)of air at 60°F and 100% RH = 37 psf. What is its VP if RH = 40%?

Accepted Answer

The answer of The vapor pressure (VP)of air at 60°F...

Question 13

Per the International Building Code, Class I vapor retarder should only be used in wood or cold- formed steel (CFS)frame assemblies in

Accepted Answer

A) Climate zones 3, 4, 5, and 6, and 7. 
B) Climate zones 3, 4, 5, 6, and marine 4. 
C) Climate zone 5, 6, 7, 8, and marine 4. 
D) Climate zones 4, 5, 6, 7, and marine 4. 
E) Climate zones 1, 2, 3, 4, and 5.

Question 14

Building assemblies are generally more vapor permeable than air permeable because

Accepted Answer

A) vapor is not really a gas. 
B) vapor is only a small part of the air- vapor mixture. 
C) vapor has only water molecules, while air is a mixture of nitrogen and several other gases. 
D) vapor pressure differential between the inside and the outside air is much greater than the corresponding air pressure differential. 
E) vapor molecules are heavier than air molecules.

Question 15

Why is an air- weather barrier (AWB)not required on sloping roofs with an attic space?

Accepted Answer

The answer of Why is an air- weather barrier (AWB)not...

Question 16

The use of membrane or liquid air barriers is required in the envelope of all heated or cooled buildings.

Accepted Answer

A) True 
 B)False

Question 17

Leakage and diffusion of a gas (such as air or water vapor)through a building envelope are two different mechanisms because

Accepted Answer

A) leakage occurs through holes, cracks, and openings in the envelope, while diffusion occurs through the body of envelope component or its material(s). 
B) leakage refers to water leaking through the envelope (such as rainwater or subsoil water)and diffusion refers to the passage of water vapor through the envelope. 
C) diffusion does not occur through a building envelope while leakage does. 
D) leakage occurs through the body of the component or material(s)of the envelope, while diffusion occurs through holes, cracks, and openings in the envelope. 
E) none of the above.

Question 18

An ice dam is likely to occur

Accepted Answer

A) at the eave of a sloping roof. 
B) at the edge of a flat roof. 
C) in the middle of a flat roof. 
D) in the middle of a sloping roof.

Question 19

In referring to the permeability of a material to air (or water vapor), do we refer to leakage, diffusion, or both?

Accepted Answer

The answer of In referring to the permeability of a...

Question 20

An air barrier is generally placed

Accepted Answer

A) toward the cold side of the envelope assembly. 
B) toward the warm side of the envelope assembly. 
C) on the exterior face of interior gypsum board. 
D) on the exterior face of an exterior sheathing. 
E) B or C.

Exam 6: Properties of the Envelope-II Air and Water Vapor Control