Fireproof sealing should be applied to the outside of the cable tray

Fireproof sealing should be applied around and on the outside of cable trays where they pass through walls, floors, or other penetrations to prevent fire and smoke spread.Proper ApplicationFireproof sealing is essential for cable trays, especially at penetrations through walls, floors, or ceilings. The sealing should be applied externally around the tray to close gaps and ensure a continuous fire barrier, preventing flames and smoke from spreading to adjacent compartments . Materials commonly used include firestop mastic, fire-rated boards, mineral wool, and specialized fireproof coatings such as PROMASTOP®-CC or KBS® Foamcoat .Installation GuidelinesSeal all gaps: Ensure that all openings around the cable tray are tightly sealed without visible cracks or voids .Use backing plates for large openings: For wide penetrations, install a fire-resistant backing plate before applying the fireproof sealant .Maintain proper thickness: Fireproof coatings and packing materials should meet the required thickness for the cable type and fire rating, typically 20–30 mm for slab penetrations .External and internal coverage: All gaps inside and around metal trays must be sealed both internally and externally to maintain fire integrity .Material selection: Choose fireproof materials compatible with the environment, such as moisture-resistant coatings for wet areas or high-density mineral wool for higher fire resistance .Maintenance and InspectionRegular inspection is necessary to ensure the integrity of the fireproof seal. Check for corrosion, damage, or gaps in the coating, especially for outdoor or high-humidity installations . Any compromised areas should be repaired immediately to maintain fire protection effectiveness.SummaryApplying fireproof sealing to the outside of cable trays is a standard and necessary practice for fire safety. It ensures that fire and smoke cannot propagate through cable penetrations, complies with fire protection standards, and maintains the safety of the building and its occupants .