A 400 square foot machine room with 3 people requires how many CFM of ventilation?

A 400 square foot machine room with 3 people requires how many CFM of ventilation?

• A. 100
• B. 200
• C. 300
• D. 400

Answer: (B)

Ventilation for a machine room is commonly estimated with a rate per square foot to ensure adequate air exchange for heat and contaminants. Using 0.5 CFM per square foot, a 400 ft² room requires 400 × 0.5 = 200 CFM. The fact that three people are in the room doesn’t change this area-based requirement in this calculation, since the problem is designed around the space size and its typical heat load. So 200 CFM is the correct total. If you used a different per-square-foot rate, you’d get other numbers (for example, 0.25, 0.75, or 1 CFM/ft² would yield 100, 300, or 400 CFM respectively). In practice, always confirm the exact rate with the applicable standard (such as ASHRAE 62.1) for the space type.

Ventilation for a machine room is commonly estimated with a rate per square foot to ensure adequate air exchange for heat and contaminants. Using 0.5 CFM per square foot, a 400 ft² room requires 400 × 0.5 = 200 CFM. The fact that three people are in the room doesn’t change this area-based requirement in this calculation, since the problem is designed around the space size and its typical heat load. So 200 CFM is the correct total. If you used a different per-square-foot rate, you’d get other numbers (for example, 0.25, 0.75, or 1 CFM/ft² would yield 100, 300, or 400 CFM respectively). In practice, always confirm the exact rate with the applicable standard (such as ASHRAE 62.1) for the space type.