Which unit is used to express the crawl space ventilation rate mentioned in the material?

Which unit is used to express the crawl space ventilation rate mentioned in the material?

• A. CFM
• B. GPM
• C. L/s
• D. m^3/h

Answer: (A)

Ventilation rate is a measure of how much air moves through a space per unit of time. In HVAC practice, especially for crawl spaces, this is expressed as cubic feet per minute, or CFM, because it directly describes the volume of air flowing each minute. GPM is gallons per minute and is used for liquids, not air. L/s is a valid metric unit for volumetric flow and could describe air flow, but the material in question uses the imperial unit CFM. m^3/h is another metric way to express volume flow per hour, which is simply a different standard that would convert to CFM with a calculation, but it isn’t the unit described in that material. So the unit used to express the crawl space ventilation rate is cubic feet per minute.

Ventilation rate is a measure of how much air moves through a space per unit of time. In HVAC practice, especially for crawl spaces, this is expressed as cubic feet per minute, or CFM, because it directly describes the volume of air flowing each minute.

GPM is gallons per minute and is used for liquids, not air. L/s is a valid metric unit for volumetric flow and could describe air flow, but the material in question uses the imperial unit CFM. m^3/h is another metric way to express volume flow per hour, which is simply a different standard that would convert to CFM with a calculation, but it isn’t the unit described in that material.

So the unit used to express the crawl space ventilation rate is cubic feet per minute.