Civil air defense ducts - Overview of fire prevention and smoke exhaust for civil air defense ducts:
1. Air supply system: There is a direct external ramp that utilizes natural air intake. If there is no direct external ramp, mechanical air intake is preferred.
2. Smoke exhaust system: The exhaust system also serves as the smoke exhaust system, and the smoke exhaust volume is calculated at 6 times per hour. In case of a fire, the dual-purpose exhaust fan is opened to enter the smoke exhaust state, and the normally open steel exhaust outlet also serves as the smoke exhaust outlet. The horizontal distance between the smoke exhaust outlet and the farthest point should not exceed 30m. When the exhaust temperature is ≥ 280 ° C, the exhaust fire damper is closed, and the supplementary air and exhaust fan are interlocked to close, and the exhaust is stopped. The smoke exhaust fan and inlet/outlet flexible joints should use fire-resistant cloth that can operate at 280 ° C for no less than 30 minutes.
3. Air supply system: The normal intake fan also serves as a fire-fighting air supply fan. In case of a fire, the air supply fan should be turned on, and the air supply volume should not be less than 50% of the smoke exhaust volume.
Civil Air Defense Ducts - Common Environmental Requirements for Civil Air Defense Ducts
To reduce the sensation and noise, shock-absorbing hooks are used for lifting equipment such as fans, and fire-resistant canvas or "three proof cloth" soft joints are used between the ventilation fan and the air duct. When the supply and exhaust ducts pass through the walls of the computer room, it is necessary to block the reserved holes with cement around them, and if necessary, soundproof cotton should be used to embed them tightly to avoid sound leakage. Both the outlet of the intake fan and the inlet of the exhaust fan are equipped with soundproof static pressure boxes. The intake and exhaust shafts near the ground buildings are treated with soundproof.
Civil Air Defense Duct - Overview of wartime ventilation planning for civil air defense ducts (Second class personnel shelter)
There are three ventilation methods: clean ventilation, filter ventilation, and barrier ventilation; Barrier protection time: Second class mask ≥ 3 hours; Allowable volume concentration of CO: ≤ 2.5%; Minimum gas exchange rate for gas defense channel: second-class mask ≥ 40 times/hour; Overpressure in the cleaning area: ≥ 30Pa ； Mobile power station during wartime: using full air cooling, fresh air passes through protective equipment and dust removal equipment, and is supplied by a diagonal flow fan to remove harmful gases and diesel engine heat dissipation in the power station, ensuring a slight negative pressure in the power station; When the air supply and exhaust ducts pass through the walls of the computer room, it is necessary to block the reserved holes with cement around them, and if necessary, use soundproof cotton to embed them tightly to avoid sound leakage; The outlet of the inlet fan is equipped with a muffler, and the inlet fan room is equipped with a return air muffler. The inlet of the exhaust fan is equipped with a muffler.