The Blast Valve Type E 2403 is a heavy duty valve that protects the interior of a shelter from blast waves caused by outside explosions. The valve is normally open with an airflow rate up to 3500 m³/h (2060 cfm). If the airflow rate exceeds a certain preset value, the valve will close instantly. It is maintenance-free and temperature and corrosion resistant. The springs are manufactured from special stainless steel and all steel parts are phosphate treated and finished with a powder coating.
