A cGMP (Current Good Manufacturing Process) FDA compliant customer manufactures products for the pharmaceutical market and has a clean room in which he has to maintain a positive pressure in order to keep the area contaminant free. He needed to be able to monitor this room to be sure his filters and fans were working properly at all times. The clean room shown as room “2” below is the critical clean room so it is necessary to enter through room 1 to get to room 2 – both on positive pressure.
We selected a zero-center Series 2000 Dwyer Magnehelic® differential pressure gauge with an 0.25″ w.c. (water column) range either side of zero whichmakes an effective monitor for proper operation of the room pressurization system. In the example shown below, differential gauge B has its high pressure port open to room 2 and its low pressure port to room 1 – gauge A has its high pressure port open to room 1 and its low pressure port open to atmosphere. With the makeup air supply damper adjusted properly, room 2 will be a higher pressure than room 1 which is at higher than atmospheric pressure and both gauges will read positive. Should the air supply to room 2 be obstructed, gauge B will read negative. If the air supply fails entirely, both gauges will read zero. For even better security, a Series A3000 Photohelic® switch/gauge will provide automatic alarm or start-up of a backup system.