Incorporating fume hoods with horizontal sashes can reduce laboratory operating costs and capital first-costs for HVAC equipment. Horizontal sashes move from side to side only. This design approach allows the sashes to act as a series of movable safety shields that always limit the size of the fume hood opening to some degree. Therefore, the fume hood is never in a fully open position unless the operator removes a sash permanently. Energy savings are from reducing the conditioned air supplied to the room, which is exhausted through the fume hood. [Saunders, 1993]
The sashes are typically provided in a series of panels usually 14 or 15 inches wide. Saunders (1993) observes that a sash "over 15 inches wide is not [considered] comfortable for most people to reach around with both arms simultaneously... [A fume hood narrower] than 6 feet wide should not be considered for a horizontal sash design." [Saunders, 1993]
