Fireproof sealing for cable trays

Cable tray penetrations can be effectively fireproofed using firestop pillows, intumescent coatings, firestop mastic, mineral wool, and certified sealing systems to prevent fire and smoke spread.

Key Fireproofing Methods

1. Firestop Pillows and Bags Intumescent fireproof pillows, such as AF BAGS, are designed to seal cable tray penetrations in walls, floors, and sandwich panels. They expand under heat to block fire and smoke, providing protection up to EI 240 (EN 1366-3). These pillows are easy to install, repositionable for maintenance, and suitable for cables up to 21 mm in diameter with a sealing depth of 120 mm . 2. Firestop Coatings and Tapes Products like FLAMMOTECT-A and DG-CR 0.7 fire protection tape form a protective shield around cables, preventing flame propagation and maintaining cable functionality during a fire. These coatings also enhance resistance to environmental factors such as UV, moisture, and chemicals, making them suitable for indoor and outdoor installations . 3. Firestop Mastic and Putty Intumescent caulks, such as IC 15WB Caulk, and moldable putty can seal gaps around cable trays and conduit penetrations. They expand when exposed to heat, filling voids and protecting structural elements and cables from fire. These materials are UL Listed and conformable to various surfaces, including metal and non-metallic boxes . 4. Mineral Wool and Fire-Resistant Boards For larger openings, fire-resistant mineral wool or fire-rated boards can be used as backing before applying mastic or sealants. This ensures a tight, reliable seal without cracks or voids, maintaining fire compartment integrity . 5. Certified Penetration Seals Systems like KBS® cable penetration seals and KBS® Panel Seal ABL provide tested solutions for concrete floors, walls, and mixed penetrations. These systems prevent fire and smoke spread while maintaining the temperature of steel structures within safe limits during a fire .

Installation Guidelines

• Ensure all gaps around cable trays are sealed completely, both internally and externally .
• For slab penetrations, provide 20–30 mm of firestopping and install a fire-support plate at the top .
• Firestop packs or pillows should be placed in an orderly sequence, with gap areas not exceeding 1 cm² and packing thickness not less than 24 cm .
• Cover plates should be square, consistent in size, and painted evenly to close the opening .
• Follow manufacturer instructions for UL or EN certified products to ensure compliance with fire safety standards .

Summary

Effective fireproof sealing of cable trays combines intumescent pillows, coatings, mastic, mineral wool, and certified penetration systems. Proper installation ensures fire and smoke containment, maintains cable functionality, and complies with international fire safety standards, making it suitable for industrial, commercial, and critical infrastructure applications.