BPI Indoor Air Quality 2 — Questions and Answers
Question 1: According to ASHRAE 62.2, which two variables are used to calculate the minimum whole-house mechanical ventilation rate for a residence?
- Building volume and number of occupants
- Conditioned floor area and number of bedrooms (Correct answer)
- Number of windows and total door area
- Ceiling height and square footage of living areas
Correct answer: Conditioned floor area and number of bedrooms
ASHRAE 62.2 calculates minimum ventilation as 0.01 cfm per square foot of conditioned floor area plus 7.5 cfm per (number of bedrooms + 1) as an occupancy proxy.
Question 2: Which type of residential ventilation system provides the greatest control over indoor air quality in an air-tight house while recovering energy?
- Natural ventilation through operable windows
- Exhaust-only ventilation using bath fans
- Balanced ventilation with a heat recovery ventilator (HRV) or energy recovery ventilator (ERV) (Correct answer)
- Supply-only ventilation using a dedicated outdoor air fan
Correct answer: Balanced ventilation with a heat recovery ventilator (HRV) or energy recovery ventilator (ERV)
Balanced HRV/ERV systems supply and exhaust equal air volumes while transferring heat (and moisture in ERVs) between air streams, maintaining IAQ and minimizing energy loss.
Question 3: An energy recovery ventilator (ERV) differs from a heat recovery ventilator (HRV) primarily because an ERV also transfers which additional component between air streams?
- Carbon dioxide between incoming and outgoing air
- Moisture (latent energy) between the exhaust and supply air streams (Correct answer)
- Airborne particulates from outdoor air to the filter
- Heat from supply air to the exhaust stream only
Correct answer: Moisture (latent energy) between the exhaust and supply air streams
An ERV transfers both sensible heat and moisture (latent energy) between air streams, making it better suited for humid climates or homes where humidity control is a priority.
Question 4: Which instrument does a BPI assessor use to measure carbon monoxide concentrations in ambient air and appliance flue gases during a home assessment?
- Manometer
- Combustion analyzer (Correct answer)
- Psychrometer
- Anemometer
Correct answer: Combustion analyzer
A combustion analyzer measures CO, CO2, and oxygen levels in flue gases and can also test ambient air CO concentrations in the living space.
Question 5: What is the recommended maximum indoor relative humidity level to inhibit mold growth and dust mite proliferation in residential buildings?
- 40%
- 50%
- 60% (Correct answer)
- 70%
Correct answer: 60%
Maintaining indoor relative humidity below 60% significantly inhibits mold growth and dust mite reproduction, which thrive in environments above 60% RH.
Question 6: When performing an indoor air quality assessment, what is the primary reason for measuring indoor CO2 concentrations?
- To detect malfunctioning combustion appliances
- As an indicator of ventilation adequacy relative to occupant load (Correct answer)
- To measure radon progeny decay products
- To identify the presence of volatile organic compounds
Correct answer: As an indicator of ventilation adequacy relative to occupant load
CO2 levels above outdoor ambient (~400 ppm) indicate inadequate ventilation; levels above 1,000 ppm suggest significant under-ventilation relative to the number of occupants.
Question 7: Which type of short-term radon test device is most commonly used by homeowners for initial screening of radon levels?
- Continuous electronic radon monitor requiring professional installation
- Charcoal canister placed in the lowest livable area for 2–7 days (Correct answer)
- Alpha track detector left in place for 3–12 months
- Water sampling kit measuring radon in the water supply
Correct answer: Charcoal canister placed in the lowest livable area for 2–7 days
Charcoal canisters are inexpensive, widely available short-term detectors exposed for 2–7 days in the lowest livable level before being mailed to a lab for analysis.
BPI Indoor Air Quality 2
According to ASHRAE 62.2, which two variables are used to calculate the minimum whole-house mechanical ventilation rate for a residence?