Fireproof materials for cable trays penetrating floors

Cable tray penetrations through floors should be sealed using fire-rated materials such as intumescent pillows, firestop caulks, mineral wool, or fire-rated boards to maintain fire-resistance integrity.Recommended Fireproof MaterialsIntumescent Firestop PillowsProducts like AF BAGS are intumescent and ablative, certified under EN 1366-3 for up to EI 240 fire resistance .They contain intumescent compounds, thermal insulators, and water-release products inside a non-combustible fiberglass casing.Suitable for cable diameters up to 21 mm with a sealing depth of 120 mm, and can be repositioned for maintenance or modifications .Firestop Caulks and MasticsIntumescent caulks, such as IC 15WB, expand under heat to seal gaps and prevent fire and smoke spread .Applied with a standard caulking gun, they are effective for sealing cut edges of mats or around cable trays.Fire-Resistant Mineral WoolMineral wool can be packed around cable trays in floor penetrations, often combined with firestop boards or mastic to ensure a tight seal .Provides thermal insulation and maintains structural integrity under fire conditions.Fire-Rated Boards and Firestop PacksFire-rated boards or firestop packs can be installed in large openings before sealing with caulk or mastic .Ensure the gap area between packs and cables does not exceed 1 cm², and packing thickness is sufficient (typically ≥24 cm for large penetrations).Installation GuidelinesTight Sealing: All gaps inside and around metal trunking or cable trays must be sealed completely, both internally and externally .Backing Plates: For large openings, install a fire-resistant backing plate before sealing .Waterstop: At slab penetrations, provide a waterstop of at least 50 mm in height and 20–30 mm of firestopping material .Tray Material: Use galvanized steel, stainless steel, or fire-resistant coated trays. Flame-retardant plastic composites are acceptable if coated with fire-retardant paint .Inspection and Maintenance: Periodically check for corrosion, deformation, or damage to the tray and fireproofing materials, and ensure seals remain intact .Fire-Resistance RatingsFirestop systems are rated according to standards such as EN 1366-3 or UL listings.Ratings like EI 120 or EI 240 indicate the duration (in minutes) the penetration can resist fire and maintain integrity .Select materials and systems based on the required fire rating for the building floor or wall.Practical ConsiderationsMaintain adequate clearance between cables to avoid heat accumulation.Use perforated or wire mesh trays to improve airflow and heat dissipation .Ensure proper alignment, grounding, and mechanical stability of trays before sealing.Cover plates should be square, evenly painted, and securely installed to close the opening . By following these material recommendations and installation practices, cable tray penetrations through floors can achieve effective fire containment, comply with safety standards, and allow for maintenance access.