Introduction The DU-III Blast & Gastight Door is a protective shelter door designed to withstand blast pressure exceeding 440 kPa (4.4 bar) and provide gas tightness. According to the product information published by Atmas Group, DU-III doors are designed for civil defence shelters and other protected facilities. They are available in single-leaf and double-leaf configurations. Atmas Group The door leaf is constructed from reinforced beams with steel cover panels. The design

Modern civil defence shelters and protected facilities require entrance systems capable of maintaining an airtight barrier between the protected interior and the external environment. In vestibule configurations, gastight doors serve as a critical engineering component by preventing the penetration of hazardous substances while preserving the integrity of the shelter envelope. The DU-IV Gastight Door is designed specifically for this purpose and is available through the offic