Preset Overpressure Valve

This overpressure valve is a one way check valve that installs on the outflow vent pipe of your shelter or safe room. It only allows air to flow out of, not into your protected space.

It is normally closed and will not open unless the air pressure inside the shelter is slightly greater than the outside air pressure. It opens when the Safe Cell is turned on and gives a little back pressure to the Safe Cell to help it create and maintain the positive pressure.

In other words, it gives the Safe Cell something to push against, helping it maintain overpressure and it won’t let any contaminated air back up through the outflow pipe into your shelter.

The Safe Cell draws air down the intake ventilation pipe, through the intake blast valve, through the filter bank, and then expels the filtered air into the shelter at a slightly higher pressure than the air outside the shelter (positive pressure or overpressure).

This gives you true ventilation – air in through the Safe Cell and out through this valve. This replenishes the oxygen and removes the carbon dioxide exhaled by the occupants.

The overpressure valve must be oriented so it points at the floor because it partially uses gravity to keep the synthetic rubber diaphragm closed. We include both wall and ceiling adapters. All joints between the overpressure valve, the adapters, and the blast valve are slip fit so they can be assembled or disassembled for cleaning or servicing without tools. It can be attached directly to the inside wall or ceiling or on a blast valve.

This is an overpressure valve mounted on a wall mounted blast valve. It utilizes the included 90 degree adapter so it is pointing at the floor.

What’s included with this item

  • One overpressure valve (center item)
  • One wall mount flange and gasket (items on right)
  • One 90 degree wall mount adapter (top left)
  • One ceiling adapter (bottom left)
  • One hard copy of the manual.

Price, availability, and ordering

Part number: ASR-50-OP
Price: $175, plus shipping
Availability: Stock item
Manual: Overpressure valve 

How to order: contact our sales department