C1- Condensation

Question 1

Name 2 sources of condensation:
1.
2.

Answer 1

Activities of building occupants.
Rain penetration.

Question 2

Condensation affects the fabric of a building by:
1.
2.
3.
4.

Answer 2

1. Mould growth.
2. Corrosion.
3. Defective insulation.
4. Swelling of timber elements.

Question 3

Condensation leads to corrosion. This can cause ________________.

Answer 3

structural failure

Question 4

What is the dew point?

Answer 4

The temperature where water vapour condenses.

Question 5

A structural temperature profile/ dew point temperature profile shows the change in temperature of different materials inside a wall.

What type of drawing is a structural/ dew point temperature profile?

Answer 5

Cross-section.

Question 6

Structural temperature profiles are used when designing a building because they identify the areas where the most __________ occurs in a wall.

So materials with a higher ___________ will be reconsidered.

Answer 6

heat loss

U-value

Question 7

Why must a contractor consider dew point temperature?

To provide an ________________________ by ensuring no health hazards are caused by ___________ from a high humidity.

Answer 7

acceptable human comfort level
mold growth

Question 8

Condensation occurs when the material temperature and the dew point profile _______.

Answer 8

meet

Question 9

Condensation can be controlled internally by:
1. A
2. D
3. E

Answer 9

1. Air conditioning.
2. Dehumidification.
3. Extractor fans.

Question 10

Dehumidifiers control condensation by ____________________________ out from a building. They are used to _______________________________ during construction.

Answer 10

removing water vapour
speed up the drying process

Question 11

Extractor fans control condensation by _______________ out from a building.

Answer 11

removing humid air

Question 12

What is interstitial condensation?

Answer 12

Condensation inside a building.

Question 13

Interstitial condensation can affect construction materials:

There is a temperature gradient across the construction material, so what happens?

Answer 13

So condensation occurs internally.

Question 14

Interstitial condensation can affect construction materials:

Condensation occurs within a construction material, leading what to happen?

Answer 14

Mould growth inside the material.

Question 15

Interstitial condensation can be avoided by changes in the design process such as:

___________ of ______________.
Use of ___________________________ to prevent moisture reaching the dew point.

Answer 15

sealing
external walls

vapour resistant materials

Question 16

Explain two benefits of using triple glazed windows:

Triple glazed windows prevent _________________, because the ___________ of the window is closer to _______________________.

Triple glazed windows _______________ inside the building, so less electricity is used. Leading to a ______________________.

Answer 16

condensation
U-value
room temperature

insulate heat
reduced energy cost

Question 17

The equation for vapour resistance is:
Vapour resistance= ___________________________
R= r x l

Answer 17

Vapour resistance= vapour resistivity x thickness

Question 18

The equation for vapour pressure drop is:
Vapour pressure drop= ______________________________________

Answer 18

(Vapour resistance/ Total vapour resistance) x Total vapour drop