Makeup air shall be not less than _____ degrees Fahrenheit, measured at the flow of air from the supply diffuser.

Makeup air shall be not less than _____ degrees Fahrenheit, measured at the flow of air from the supply diffuser.

• A. 55
• B. 50
• C. 68
• D. 60

Answer: (B)

Makeup air is the air brought in to replace air exhausted from a space, and its temperature at the point it enters the space determines occupant comfort. The requirement sets a minimum of 50°F to be sure the air delivered from the supply diffuser isn’t uncomfortably cold for occupants, especially during cold weather. Measuring at the diffuser reflects what people actually experience in the space, not just the temperature before the air mixes with room air. Temperatures like 55, 60, or 68°F would also satisfy the rule, but they are higher than the mandated minimum. The question asks for the minimum value, so 50°F is the correct baseline.

Makeup air is the air brought in to replace air exhausted from a space, and its temperature at the point it enters the space determines occupant comfort. The requirement sets a minimum of 50°F to be sure the air delivered from the supply diffuser isn’t uncomfortably cold for occupants, especially during cold weather. Measuring at the diffuser reflects what people actually experience in the space, not just the temperature before the air mixes with room air.

Temperatures like 55, 60, or 68°F would also satisfy the rule, but they are higher than the mandated minimum. The question asks for the minimum value, so 50°F is the correct baseline.