1. General requirements for reserved embedding in air-defence zones
The reserved embedding covers conduit and sleeves for every trade inside the air-defence zone. At each personnel entrance and connection opening, several spare conduits are embedded in the door-frame walls of the protective airtight and airtight doors, using galvanised steel pipe of 65 mm bore and wall thickness at least 2.5 mm. Cable routes crossing exterior walls, open-air walls, protective airtight partitions and airtight partitions are pre-embedded with spare conduits and given protective airtight or airtight treatment. One low-voltage cable is led from the basement switchroom to each air-defence distribution box; the wartime standby power from the neighbouring regional station must be debugged within the 3-day conversion window, and the conduit for the power circuit is pre-embedded in peacetime. Reserve openings are provided for all equipment installation.
2. Notes for air-defence construction
All pressurised pipes crossing the protective airtight partitions, airtight partitions and roof need reserved protective airtight sleeves, made per atlas 07FS02. Gravity drainage must not cross air-defence partitions or roof. Blast floor drains follow 07FS02; control the post-pour layer thickness, set the drain level correctly, remove the cover for separate storage after fitting, and pack the drain with sawdust in a woven bag to prevent blockage until the floor is finished. Concealed electrical conduits in the zone use galvanised steel pipe of wall at least 2.5 mm; those crossing partitions and roof follow 05SFD10 for protective airtight treatment, and exposed runs need reserved airtight sleeves per 05SFD10. Reserve spare conduits for wartime signal and test pipes through protective walls. Air-defence ventilation pipes crossing protective walls must be reserved with airtight-compliant conduits during structural work, with size, coordinates and level coordinated across trades to avoid clashes.
3. Airtight practices through protective walls
Electrical steel conduits use a steel sealing rib, 3–4 mm thick, welded to the structural reinforcement. Rigid flame-retardant plastic conduits use a same-material plate rib over 5 mm thick. Ventilation steel pipe is at least 3 mm thick, sealing rib 5–6 mm, projecting 100 mm from the wall. Sealing rib is centred in the wall thickness and welded to the surrounding reinforcement; the conduit axis is perpendicular to the wall.
4. Embedding of key devices
Blast floor drains are set in防毒 channels, airtight channels, simple decontamination rooms, filter rooms and diffusion rooms; they are embedded before pouring the basement slab or screed, with the floor falling 0.5% to the drain, using galvanised steel pipe because of the threaded connection. Three models exist: FBFDD50, FBFDD80, FBFDD100 with outlet sizes DN50, DN80, DN100. Blast overpressure automatic exhaust valves sit in防毒 channels or simple decontamination rooms; a short pipe with sealing rib (3 mm steel plate, diameter d=250 mm, two coats of anti-rust paint) is embedded, then the flange and reducer are welded during fit-out, with the flange vertical and the valve opening toward the exhaust. Pressure-measurement pipes are embedded as required.