Construction Specifications:

"Design Specification for Electromagnetic Pulse Protection Engineering - GJB 3928-2000"

"Code for Design Standards of Civil Air Defense Command Engineering RFJ1-2006"

Requirements for Communication Engineering Design of Civil Air Defense Command Centers RFXB 02-2006

"Design Specifications for Electromagnetic Pulse Protection of Civil Air Defense Projects" RFJ 01-2001

"Measurement Method for Shielding Effectiveness of Electromagnetic Shielding Rooms" GB/T 12190-2021 Standard

Nuclear electromagnetic pulse (EMP) protective shielding rooms are used in underground engineering for civil defense command centers and similar locations. They are typically categorized into three levels of protection.

Grade I Shielding Room: Sensitive equipment operation is not interfered with. Electric field shielding efficiency >90dB, magnetic field shielding efficiency >80dB.

Level 2 Shielded Room: Sensitive equipment remains undamaged. Electromagnetic field shielding efficiency >60dB, magnetic field shielding efficiency >60dB.

Level Ⅲ Shielding: Secondary sensitive equipment is not damaged. Electric field shielding effectiveness > 50dB, magnetic field shielding effectiveness > 50dB.

Installation Instructions:

Ⅰ Grade Shielding Room: Shield body: six sides use galvanized rectangular tube discontinuous welded steel frame; the top and four walls are made of 2mm galvanized steel plate for shielding layer; the bottom is made of 3mm galvanized steel plate for shielding layer, with full welding required. Accessories: Both strong and weak power lines must pass through a filter before connecting; ventilation inlets and outlets are equipped with ventilation cutoff waveguide windows and electrically shielded doors.

Level II Shielded Room: The top and four walls of the shielding body are lined with galvanized steel plates (or tinplate) in an integrated manner, with the bottom made of 3mm galvanized steel plates welded together; both strong and weak power lines must pass through filters for connection, and ventilation inlets and outlets are equipped with ventilation cutoff waveguide windows. The shielding door uses a simple beryllium bronze spring contact type. For rooms requiring construction similar to others, the Level II Shielded Room can refer to the construction methods of the Level I Shielded Room.

Grade III Shielding: The entire project's bottom plate, side walls, and top plate are required to have longitudinal rebars throughout, both internally and externally, welded to form individual closed loops (Faraday cage). The underground building structure is a complete hexahedral concrete reinforced steel mesh, with the external steel mesh grid nodes arranged in an alternating pattern (0.5-1 meter spacing).

Grounding System: The grounding electrodes and busbars are connected in a radial horizontal convergence to the central grounding body, with the grounding resistance to be less than 0.5Ω.

Enclosure Room Renovation: Floor with suspended anti-static flooring; ceiling with micro-perforated aluminum ceiling tiles; walls with color steel plates or aluminum-plastic panels.

Indoor electrical supplies include: heavy-duty distribution boxes, communication distribution boxes, grating lights, wall switches, and plug-in sockets, etc.

Note: Ensure key measures such as moisture and corrosion prevention, grounding, and ventilation for civil air defense underground projects.