SYSTEM FOR CONTROLLING THE DIFFERENTIAL PRESSURE OF A ROOM HAVING LABORATORY FUME HOODS

摘要

A system whereby the pressure of a roomcontaining one or more fume hoods, such as a laboratory, isto maintained at a predetermined level relative to thepressure of a reference space in the building, which may bethe pressure in an adjacent corridor or an adjacent room orthe like. The system involves a room controller which ispart of the heating, ventilating and air conditioningapparatus of the building. The room controller is of thetype which can receive electrical signals from each fumehood controller, which signals are proportional to thevolume of air that is being exhausted through each fumehood. The volume indicating signals communicated from eachof the fume hood controllers to the room controller enablethe system to modulate the volume of air that is beingsupplied to the room and thereby maintain the differentialpressure at the desired level with relatively quickresponse times.