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Blast & Overpressure Valves

Blast and Overpressure Valves for Ventilation and Air Filtration Systems
Blast overpressure valve shelter

Atmas presents a wide selection of blast valves and overpressure valve for ventilation and air filtration systems of civil defence shelters, safe rooms, industrial applications and other types of protective structures which require protection of ventilation ways and internal space from blast wave pressure coming from outside.

Our professional, tested and certified valves are installed in thousands of facilities to protect people and equipment. The valves are approved by various civil defence authorities and certified according to most modern standards.

The blast valves provide automatic dual action operation protecting both from positive and negative phases of the blast.


The valves we offer can be used in new construction or retrofitted in existing (modernization) projects.

Blast Valves

Blast valves are protective valves which are normally open and allow movement of air for both directions (in and out of the protected space). Blast valves are usually installed on ventilation openings or on air ducts of the ventilation system for protecting the inner space of the shelter, room or a structure from blast pressure wave (both positive and negative phases). 

Overpressure Valves / Differential Pressure Valves​

Overpressure valves are normally closed valves designed to maintain the overpressure inside the protected area in predetermined values and can be blast protected. The operation of such valve is to stay closed until a predefined level of overpressure reached in the chamber / shelter and automatically to release the air / pressure to prevent it raising the allowed values.

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