BPI Air Sealing 2 — Questions and Answers
Question 1: Which building diagnostic tool is primarily used to measure the airtightness of a building envelope?
- Combustion analyzer
- Blower door (Correct answer)
- Duct blaster
- Infrared camera
Correct answer: Blower door
A blower door depressurizes or pressurizes a building to measure air leakage through the envelope.
Question 2: What does ACH50 measure in building performance testing?
- Air changes per hour at 50 Pascals of pressure (Correct answer)
- Airflow cubic feet per hour at 50°F
- Annual cooling hours above 50°F
- Average ceiling height in a 50-year-old building
Correct answer: Air changes per hour at 50 Pascals of pressure
ACH50 expresses the number of times a building's air volume is exchanged per hour when pressurized to 50 Pascals.
Question 3: What is the primary air sealing concern at the top plates of interior partition walls?
- Thermal bridging through studs
- Air bypass into the attic through unsealed gaps (Correct answer)
- Moisture condensation on framing members
- Pest infiltration through gaps
Correct answer: Air bypass into the attic through unsealed gaps
Unsealed top plates allow conditioned air to bypass insulation and escape into the attic, significantly increasing energy loss.
Question 4: Which material is best suited for air sealing large irregular gaps around pipes and wires penetrating a top plate?
- Fiberglass batt insulation
- Two-part spray polyurethane foam (Correct answer)
- Rigid foam board
- Housewrap tape
Correct answer: Two-part spray polyurethane foam
Two-part spray polyurethane foam expands to fill irregular voids and adheres well to multiple substrates, making it ideal for large irregular gaps.
Question 5: In BPI building science, what is the 'thermal boundary' in relation to air sealing?
- The outdoor temperature at which heating begins
- The plane where insulation and air barrier align to separate conditioned from unconditioned space (Correct answer)
- The boundary between different R-value insulation zones
- The legal property line for energy code compliance
Correct answer: The plane where insulation and air barrier align to separate conditioned from unconditioned space
The thermal boundary is the continuous plane combining air barrier and insulation that separates conditioned from unconditioned space.
Question 6: What pressure differential does a standard blower door test use to characterize building airtightness?
- 25 Pascals
- 50 Pascals (Correct answer)
- 75 Pascals
- 100 Pascals
Correct answer: 50 Pascals
The standard blower door test pressurizes or depressurizes the building to 50 Pascals to measure CFM50 or ACH50.
Question 7: When air sealing recessed light fixtures in an attic floor, what is the primary safety concern with older IC-rated fixtures?
- Electrical shorts from foam contact
- Overheating if airflow around the fixture is restricted (Correct answer)
- UV degradation of sealant materials
- Condensation forming inside the fixture housing
Correct answer: Overheating if airflow around the fixture is restricted
Even IC-rated fixtures can overheat if air sealing traps heat, so airtight (AT) rated fixtures or sealed covers are recommended.
BPI Air Sealing 2
Which building diagnostic tool is primarily used to measure the airtightness of a building envelope?