Isolation and Critical Room Information

The pressure necessary to prevent contaminant infiltration into cleanrooms, isolation rooms and operating rooms is astoundingly low. Depending upon the function of the controlled room, specifications can vary from a differential of 0.01 to 0.15 inches of water. Too low, and there won't be enough air movement to contain particles. Too high, and the air will move into places that it shouldn't, like ceiling joints, and it will become difficult to open doors. With such a tight tolerance of a miniscule differential pressure required, the DP measuring device feeding the air handling equipment must be extremely accurate, sensitive and stable.

Cleanrooms and operating rooms require a positive pressure; the pressure in the room is maintained at a higher level than the surrounding areas to keep contaminants from entering. Dust particles and microbes outside will be repelled by higher pressurized air spilling out of the room whenever a door is opened. Often, these environments consist of several separately controlled rooms surrounding or leading up to the critical area which can include a gowning zone and an airlock. Each of these areas will be held at slightly different pressures to ensure that the air always moves in the correct direction.

In hospital "airborne infection isolation rooms", the opposite case is true. To keep contaminants from exiting the room, a diminutive volume of the room's atmosphere is evacuated to create a lower pressure than the surrounding areas. This negative pressure will control the direction of the air flow. When the door is opened, air from the adjacent area will push into the isolation room, preventing virus or bacteria from leaving and infecting staff, visitors or other patients.

The Ashcroft® CXLdp and DXLdp ultra-low pressure transmitters are specifically designed to meet these extreme requirements. Offered in accuracies up to 0.25% of span, both are able to proficiently resolve DP changes down to a fraction of an inch of water and deliver the proven reliability essential to ensuring that contaminants and diseases are appropriately contained for maximum protection of people and processes.