ASHRAE Terminology

(1) dedicated replacement air. (2) air brought into a building from the outdoors to replace air that is exhausted. Makeup air may or may not be conditioned. (3) any combination of outdoor and transfer air intended to replace exhaust air and exfiltration. (4) in a cleanroom, air introduced to the secondary air system for ventilation, pressurization, and replacement of exhaust air. (5) in a laboratory or kitchen, outdoor air deliberately brought into the building from the outside and supplied to the vicinity of an exhaust hood to replace air, vapor, and contaminants being exhausted. Makeup air is generally filtered and fan forced, and it may be heated or cooled depending on the requirements of the application. Makeup air may be delivered through outlets integral to the exhaust hood or through outlets in the same room.