Fireproof partition wall for cable trays

Cable trays passing through walls must be firestopped using certified materials such as firestop packs, intumescent caulks, or preformed pathway devices to maintain wall fire ratings and prevent smoke and flame spread.Firestopping Materials and Methods1. Firestop Packs and Mineral Wool: For large openings, install a fire-resistant backing plate before sealing. Use firestop packs or fire-resistant mineral wool to fill gaps around the cable tray. Ensure the packing thickness is sufficient (typically ≥24 cm) and the gap area between packs and cables does not exceed 1 cm². Seal all gaps inside and around metal trunking completely, both internally and externally, to prevent fire and smoke penetration . 2. Intumescent Caulks and Putty: Products like 3M Fire Barrier Moldable Putty+ or IC 15WB Caulk are pliable, easy to mold, and adhere to most surfaces. They expand under heat to seal openings and protect structural steel and cable trays. These materials are suitable for both new construction and retrofits, providing UL-listed fire ratings for concrete and gypsum walls . 3. Preformed Firestop Devices: For retrofit or high-density cable trays, devices such as EZ-Path Cable Tray Retrofit Device or Hilti's CP 653 BA speed sleeve allow quick, code-compliant firestopping without removing existing cables. These devices restore fire resistance, prevent smoke leakage, and maintain flexibility for future cable additions or changes .Installation GuidelinesSequence: Complete floor and wall finishes, install shaft doors, then perform firestopping.Gap Management: Ensure tight, reliable sealing without visible cracks or voids.Cover Plates: Use square, evenly painted cover plates to close openings.Waterstop: At slab penetrations, provide 20–30 mm of firestopping and a waterstop of at least 50 mm in height .Compliance: Follow UL 1479, EN 13501-2, or other relevant standards for fire ratings and certification.Practical ConsiderationsFlexibility: Preformed devices and moldable putty allow easy re-penetration for maintenance or cable upgrades.Compatibility: Choose materials compatible with wall type (concrete, gypsum, or composite) and cable tray style (ladder, solid-bottom, or channel).Inspection: Ensure all firestopping is visually inspected and certified to maintain fire compartment integrity. Using these methods ensures that cable trays passing through walls maintain the required fire rating, prevent smoke and flame spread, and allow for safe, flexible electrical installations in both new and existing buildings.