Which term describes how often air in a storage facility is replaced per hour?

Which term describes how often air in a storage facility is replaced per hour?

• A. Ventilation rate per minute
• B. Air turnover speed
• C. Air changes per hour
• D. Air refresh cycles

Answer: (C)

Air changes per hour describes how often the air in a space is replaced with fresh air in one hour. This term directly captures the replacement frequency per hour, which is exactly what the question asks. It comes from the ventilation rate and the room’s volume: ACH = Q / V, where Q is the air moved and V is the space volume. For example, if a storage room receives 500 cubic feet of air per minute and is 5,000 cubic feet in volume, the ACH is (500 × 60) / 5,000 = 6 changes per hour. The other options either refer to a rate per minute, use nonstandard wording, or imply cycles rather than a steady rate of replacement, so they don’t describe how often air is replaced per hour as clearly.

Air changes per hour describes how often the air in a space is replaced with fresh air in one hour. This term directly captures the replacement frequency per hour, which is exactly what the question asks. It comes from the ventilation rate and the room’s volume: ACH = Q / V, where Q is the air moved and V is the space volume. For example, if a storage room receives 500 cubic feet of air per minute and is 5,000 cubic feet in volume, the ACH is (500 × 60) / 5,000 = 6 changes per hour. The other options either refer to a rate per minute, use nonstandard wording, or imply cycles rather than a steady rate of replacement, so they don’t describe how often air is replaced per hour as clearly.