The Automatic Sash Operator is a great solution that offers energy savings to the laboratory and provides user safety. It is designed to be factory mounted on a Mott chain drive vertical rising sash fume hood. When combined with Variable Air Volume systems, large energy savings will result because the sash closes after the user exits the work area thus reducing exhaust volume and therefore also reducing energy consumption. The sash will automatically open to the pre-set working height when the operator returns to the fume hood working area. This system is also equipped with a safety light beam, which will sense an obstruction and cause the sash to disengage immediately once the presences of an object is detected.