The Overpressure Blast Valve Type A 803 are used to stop explosive/implosive blast waves from entering a shelter or secure room, as well as to regulate the air pressure inside the space. The valve, normally closed, allows for an airflow rate of 200-800 m³/h (115-470 cfm). It is maintenance-free and withstands heat and corrosion. The springs are manufactured from special stainless steel and all steel parts are phosphate treated and finished with a powder coating.
