What is the minimum exhaust rate at which makeup air must be provided for exhaust hood systems?

The minimum exhaust rate at which makeup air must be provided for exhaust hood systems is 400 cubic feet per minute. This requirement is based on the need to balance the air pressure within a space. When exhaust hoods remove air to eliminate smoke, grease, odors, and other contaminants from the kitchen environment, it is crucial to ensure that an adequate amount of makeup air is introduced to replace the expelled air.

This is important for maintaining indoor air quality, ensuring that the kitchen remains well-ventilated, and preventing negative pressure that can lead to issues such as backdrafting of combustion appliances or infiltration of unconditioned air from outside. The specification of 400 cubic feet per minute aligns with the guidelines set forth in the North Carolina Mechanical Code, emphasizing the importance of proper ventilation practices in commercial kitchen settings. By adhering to this minimum rate, facility operators can ensure both compliance with local regulations and an efficient working environment.