Adjustable Overpressure Valve
The Adjustable Overpressure Valve is critical to creating an overpressure in the protected space by adding the proper resistance to the outflowing air. This valve is normally closed and will not open unless the air pressure inside the shelter reaches the opening pressure set by the adjustment cap. When used with an ASR-100-AV-NBC Safe Cell, the adjustment range is zero to 1.75 inches of water column.
The adjustment cap is located at the bottom of the valve assembly. Tightening this cap increases the pressure in the protected space. This allows you to compensate for a shelter that is not entirely sealed up – within reason. This valve should be used with the Differential Pressure Gauge.
This gives you true ventilation – air in through the Safe Cell and out through this valve preventing the buildup of carbon dioxide exhaled by the occupants. Carbon dioxide poisoning will incapacitate and kill the occupants of an enclosed space without ventilation long before oxygen deprivation.
This valve can be installed onto a Blast Valve. A good rule of thumb is that if you are underground, you need blast valves and if you are above ground, you do not – unless you have a hardened structure above ground. There is not much need for blast valves unless you have a blast resistant shelter.
Any protected space will benefit from this valve, especially if it is well sealed, then this overpressure relief valve is a necessity.
Here is a quote from an e-mail we receieved from a customer who purchased three of these adjustable overpressure valves in May of 2009: