Details of Fireproof Sealing for Cable Trays

Fireproof sealing for cable trays involves using approved firestop materials and installation techniques to prevent fire and smoke propagation through wall, floor, and slab penetrations.

Key Principles

Fireproof sealing ensures that openings where cable trays pass through walls, floors, or slabs are tightly sealed to maintain the integrity of fire-rated barriers. Openings must be free of cracks or voids, and large penetrations may require a fire-resistant backing plate before sealing. Proper layout and positioning facilitate installation, maintenance, and compliance with fire safety standards.

Materials Used

Common firestop materials for cable trays include: Firestop packs and mineral wool: Used to fill gaps around cables; packing thickness should be at least 24 cm, and gaps should not exceed 1 cm². Firestop mastic and intumescent caulks: Seal gaps and expand under heat to block fire and smoke. Fire-rated boards: Provide structural fire resistance for larger openings.

Fire protection coatings and tapes: Products like FLAMMOTECT-A and DG-CR 0. 7 form protective shields around cables, preventing flame propagation and enhancing environmental resistance. Modular sealing systems: Roxtec solutions allow flexible, multi-cable sealing with certified fire ratings, suitable for walls, floors, and enclosures.

Installation Guidelines

Preparation: Ensure floor and wall finishes are complete, and shaft doors are installed. Large openings may require a fire-support plate or backing plate. Cable Routing: Route cables in accordance with layout principles, maintaining separation between power and signal cables and ensuring adequate clearance for heat dissipation.

Firestop Application: Place firestop packs in an orderly sequence, seal all gaps inside and around metal trunking, and apply mastic or caulk as needed. Cover plates should be square, evenly painted, and securely installed. Penetration Sealing: For slab penetrations, provide 20–30 mm of firestopping and a waterstop of at least 50 mm at floor level.

Inspection and Maintenance: Regularly check tray connections, grounding continuity, and the integrity of fireproof coatings or seals. Replace or repair any damaged sections immediately.

Compliance and Certification

Fireproof sealing systems should comply with standards such as UL 1479 and EN 1366, ensuring tested fire resistance. Modular systems like Roxtec are certified by major classification authorities and can accommodate future cable additions without compromising fire safety.

Additional Considerations

Use perforated or wire mesh trays to improve airflow and prevent heat accumulation. Select tray materials based on environment: galvanized steel for indoor, stainless steel or hot-dip galvanized for outdoor, and corrosion-resistant materials for high-humidity or chemical exposure. Fireproof trays and coatings are intended for flame containment and isolation, not for unrelated structural functions.

By following these guidelines, fireproof sealing for cable trays can effectively prevent fire and smoke spread, maintain operational reliability, and comply with safety regulations.