The ASR-50-OP wall mount configuration shown
See manual below for other configurations

Click on the image above to view this manual (PDF)

This overpressure relief valve is critical to creating an overpressure in the protected space by adding the proper, metered resistance to the outgoing airflow. The valve is normally closed and will not open unless the air pressure inside the shelter is slightly greater than the outside air pressure.

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 and should be connected to a blast valve to provide overpressure protection to the outflow vent. We can easily configure this at the factory for you.