Analysis of field influence factors of fume hood inlet face velocity control

Based on the spot test of the chemical laboratory in a Shanghai test center, analyzes the average face velocity and face velocity diversity, and states that the fume hood with motorized dampers cannot desirably meet the control requirement due to various damper opening position, system location and operation state involved. Recommends to equip the fume hood with VAV exhaust control valves with velocity measurement feedback for meeting the velocity requirement with the closed-loop control and simplifying the operation by the laboratory personnel.