Selection Guide — AIR VOLUME — LOW CONSTANT VOLUME
Low Constant Volume fume hoods use a restricted sash opening or a lower face velocity, or both to reduce the exhaust quantity of air, measured in cubic feet per minute (CFM), necessary to contain fumes with a typical face velocity of 80-120 FPM. Traditionally, such fume hoods can reduce the exhaust CFM from 40% to 60% from Open By-pass levels.