When the gas protection function is enabled, the high-pressure air would be depressed by depressurizing system and then fresh air would be supplied to the main room. A micro-positive pressure of 50pa would be kept in the main room and 25pa in the air-lock area. Due to the internal pressure in the temporary refuge shelter is slightly higher than the atmosphere pressure, the internal air will vent through the check valve and the hazardous gas will be blocked outside.
Control room of temporary refuge shelter, toxic gas refuge cabin