Cable trays that penetrate walls in civil defense facilities

Cable trays penetrating walls must be properly firestopped and sealed to maintain structural integrity and fire safety in civil defense applications.Purpose and Importance

Cable tray wall penetration allows electrical and communication cables to pass through walls while preserving the fire resistance and structural integrity of the building. This is critical in civil defense and safety-sensitive environments, as any breach in fire-rated walls can compromise fire containment, emergency systems, and overall safety compliance . Proper penetration ensures organized cable routing, reduces clutter, and facilitates maintenance and upgrades .

Firestopping Requirements

When cable trays penetrate walls or slabs, firestopping measures must be applied to prevent fire and smoke spread:

• Firestop Materials: Use fire-rated boards, firestop packs, firestop mastic, or fire-resistant mineral wool .
• Packing and Gaps: Firestop packs should be installed in sequence, with gaps between packs and cables not exceeding 1 cm², and packing thickness of at least 24 cm .
• Sealing: All gaps inside and around metal trunking must be sealed tightly, both internally and externally, without visible cracks or voids .
• Support Plates: For slab penetrations, a fire-support plate should be installed at the top, with 20–30 mm of firestopping material .
• Large Openings: Install a fire-resistant backing plate before sealing to ensure complete protection .

Penetration Seal Systems

Several specialized systems are available to maintain fire and structural safety:

• Modular Firestop Systems: Systems like FIRSTO or RISE® use expanding inserts and sealants to provide fire, water, and gas protection for multi-cable penetrations .
• Intumescent Materials: Expanding intumescent seals are effective for combustible or heat-sensitive services, closing apertures during a fire .
• Sleeves and Frames: Cast-in sleeves or steel frames (e.g., WSP weatherstops) provide structural support and allow easy installation and maintenance while maintaining fire and water resistance .

Installation Best Practices

• Ensure alignment and positioning of cable trays to facilitate installation and future maintenance .
• Use wall sleeves or pre-formed openings to guide trays through walls without damaging the structure .
• Cover plates should be square, evenly painted, and dimensionally consistent to close openings neatly .
• Verify that all materials and systems are tested and certified for the specific wall type and fire rating .

Summary

For civil defense applications, cable tray penetrations must combine structural integrity, fire resistance, and accessibility. Using certified firestop materials, modular sealing systems, and proper installation techniques ensures compliance with safety codes, prevents fire spread, and maintains operational reliability of critical electrical and communication systems .