when the supply air volume&time of itive pressure air supply system is out of control,，樓梯間壓力傳感器廠家,， the normal escape route may be too high because of the itive pressure of the front room，壓力傳感器廠家,， the fire door can not open the serious cequences. in view of the above ciderati,， the sichuan institute of fire science combined with experience to provide data of residual pressure value. by controlling the opening&closing of the by-pass valve， the differential control system can effectively control the residual pressure of the mechanical pressurized air supply system within the reasonable range required by the national standard ——40-50 pa in the smoke-proof stairwell,， the front room,， the shared front room，前室壓力傳感器廠家,， the front room of the fire elevator room&the enclosed refuge floor (room) are 25-30pa.