Insulation and Interior Inspection Section#1 Insulation and Ventilation Quiz#3

This study session covers moisture flow in houses, including moisture sources, how moisture moves, condensation and its effect in buildings, how air leakage affects moisture flow in homes and hot climates.

The estimated completion time for this study session is sixty minutes.

Objectives
At the end of this study session, you should be able to:

• List eight sources of moisture in house air.
• Define absolute and relative humidity.
• Define saturated air.
• List four ways that moisture moves through homes.
• Describe in three sentences stack effect.
• Describe in two sentences neutral pressure plane.
• Define dew point temperature.
• Rank the importance of vapor diffusion and air leakage in condensation problems n homes.
• Describe drying potential in two sentences.
• Explain in three sentences why newer homes are more likely to have condensation problems.
• List five possible ways to control moisture and condensation problems.
• Describe in three sentences how condensation problems are different in hot, humid climates.

• Question 1

  Needs Grading

  	Define absolute humidity.
  	Selected Answer: Absolute humidity is a measure of the actual amount of moisture in the air. This can be measured in grains (0.002285 ounces) of moisture per pound of dry air.  Correct Answer:   The actual amount of moisture in the air Response Feedback: [None Given]

• Question 2

  Needs Grading

  	Define dew point temperature.
  	Selected Answer: For any bundle of air, the dew point temperature is the temperature at which condensation will just start to occur. It's just another way of saying the humidity level is 100%.  Correct Answer:   The point at which condensation will start to occur Response Feedback: [None Given]

• Question 3

  Needs Grading

  	Define relative humidity.
  	Selected Answer: Relative Humidity (RH) is given as a percentage. It is the amount of moisture in the air relative to the amount of moisture the air could hold if saturated.  Correct Answer:   The amount of moisture in the air relative to the amount it could hold if saturated, expressed as a percent. Response Feedback: [None Given]

• Question 4

  Needs Grading

  	Define stack effect.
  	Selected Answer: Warm air is lighter than cool air because it is less dense. The warm air rises and expands, creating a higher pressure near the top of the house. This relatively high pressure air tries to get out of the house through any cracks or holes it can find. The cooler, lower pressure air near the bottom of the house allows outdoor air in through cracks and holes.  Correct Answer: As warm air rises in a building, it expands, creating a higher pressure near the top of the house. This higher pressure air tries to escape through any opening it can find. The cooler, lower pressure air near the bottom of the house tends to allow outdoor air in through any openings it finds. Response Feedback: [None Given]

• Question 5

  Needs Grading

  	How are condensation problems different in hot, humid climates?
  	Selected Answer: Air leakage to building will create condensation in the wall.  Correct Answer:   The direction of moisture movement is from the outside to the inside. We worry about air leakage into rather than out of the house. Air conditioning creates a drier, cooler interior, thus increasing the potential for moisture problems. Response Feedback: [None Given]

• Question 6

  Needs Grading

  	List at least eight sources of moisture in house air. (You may come up with ten.)
  	Selected Answer: 1. People washing their face and hands and brushing their teeth.  2. Taking showers and baths. 3. Cooking and washing dishes. 4. Washing clothes. 5. Washing floors, walls and furnitures.  6. Watering plants. 7. People breathing and perspiring.  8. Damp soil in subgrade spaces 9. Firewood. 10. Pets Correct Answer: 1. Washing faces, hands, brushing teeth 2. Showers and baths 3. Cooking and washing dishes 4. Washing clothes 5. Washing floors, walls, furniture 6. Watering plants 7. Breathing and perspiring 8. Damp soil in subgrade spaces 9. Firewood drying 10. Pets Response Feedback: [None Given]

• Question 7

  Needs Grading

  	List five possible ways to control moisture and condensation problems in homes.
  	Selected Answer: 1. Produce less moisture 2. Keep the condensing surfaces warmer 3. Stop air leakage 4. Flush air out faster 5. Exhaust warm, moist air directly outside Correct Answer:   1. Produce less moisture 2. Keep the condensing surfaces warmer 3. Stop air leakage 4. Flush the air out faster 5. Exhaust warm, moist air directly outside Response Feedback: [None Given]

• Question 8

  Needs Grading

  	List four ways moisture moves through homes.
  	Selected Answer: 1. Bulk moisture - these are leaks 2. Capillary action - this is wicking or rising damp 3. Air-transported moisture - the water vapor in the air moves with the air 4. Vapor diffusion - water vapor moves from high to low pressure areas without air movement Correct Answer:   1. Bulk moisture 2. Capillary action 3. Air-transported moisture 4. Vapour diffusion Response Feedback: [None Given]

• Question 9

  Needs Grading

  	Rank the importance of vapour diffusion and air leakage in condensation problems in homes.
  	Selected Answer: The movement of air in and out of building is about 100 times more important than vapor diffusion. Correct Answer:   1. Air leakage (most important) 2. Vapour diffusion Response Feedback: [None Given]

• Question 10

  Needs Grading

  	What is meant by drying potential?
  	Selected Answer: The ability to dry. Correct Answer:   The ability of a material or assembly to dry out after it has gotten wet Response Feedback: [None Given]

• Question 11

  Needs Grading

  	What is meant by neutral pressure plane?
  	Selected Answer: At some point in the house, there is a level where the pressure is neither positive or negative. This is named neutral pressure plane.  Correct Answer:   The point in the house where the positive and negative pressures balance each other out exactly Response Feedback: [None Given]

• Question 12

  Needs Grading

  	What is meant by saturated air?
  	Selected Answer: The amount of moisture air can hold without forming condensation. Correct Answer:   The maximum amount of moisture air could hold at a given temperature without condensing Response Feedback: [None Given]

• Question 13

  Needs Grading

  	Why are new homes more likely to have condensation problems than old homes?
  	Selected Answer: New homes are more air-tight for energy efficiency. It has less air exchange with outside.  Correct Answer: More insulation and tighter building cavities allowed less air leakage. The longer the air stays in the building, the more moisture is likely to be in it. Since the walls and roofs are cooler (more insulation), the moist air passing through will cool and condense at a higher rate than before. Response Feedback: [None Given]