Indoor Air Quality Flashcards

According to ASHRAE 62.2, which two variables are used to calculate the minimum whole-house mechanical ventilation rate for a residence?

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.

Which type of residential ventilation system provides the greatest control over indoor air quality in an air-tight house while recovering energy?

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.

An energy recovery ventilator (ERV) differs from a heat recovery ventilator (HRV) primarily because an ERV also transfers which additional component between air streams?

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.

Which instrument does a BPI assessor use to measure carbon monoxide concentrations in ambient air and appliance flue gases during a home assessment?

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.

What is the recommended maximum indoor relative humidity level to inhibit mold growth and dust mite proliferation in residential buildings?

Answer: 60%

Maintaining indoor relative humidity below 60% significantly inhibits mold growth and dust mite reproduction, which thrive in environments above 60% RH.

When performing an indoor air quality assessment, what is the primary reason for measuring indoor CO2 concentrations?

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.

Which type of short-term radon test device is most commonly used by homeowners for initial screening of radon levels?

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.