Fireproofing requirements for cable tray sealing

Effective fireproofing for cable tray penetrations can be achieved using intumescent pillows, firestop caulks, mineral wool, or specialized fire-resistant coatings, all designed to prevent fire and smoke spread while maintaining cable functionality.

Intumescent Fireproof Pillows

Intumescent pillows, such as AF BAGS, are widely used for sealing cable tray penetrations. They expand under heat to fill gaps, providing fire resistance up to EI 240 minutes according to EN 1366-3 standards. These pillows are encased in non-combustible fiberglass and contain intumescent compounds, thermal insulators, and water-release agents to minimize sealing depth.

They are suitable for cables up to 21 mm in diameter and can be repositioned for maintenance or modifications.

Firestop Caulks and Putty

Firestop caulks, like 3M IC 15WB, and moldable putties are intumescent, halogen-free, and easy to apply with a standard caulking gun. They are designed to seal gaps around cable trays, conduits, and insulated pipes, preventing heat and smoke penetration. These products conform to irregular surfaces and maintain fire ratings for walls and slabs, with UL-listed systems providing up to 3-hour F-rating for concrete walls.

Mineral Wool and Fire-

Resistant Boards

For larger openings or structural penetrations, fire-resistant mineral wool or fire-rated boards can be used as backing material before applying caulks or sealants. This ensures a tight, reliable seal and enhances fire resistance. Proper installation requires filling gaps completely, maintaining a packing thickness of at least 24 cm, and using cover plates to close the opening.

Fire-

Resistant Coatings

Specialized coatings, such as FLAMMOTECT-A or KBS® Coating, provide a protective layer around cables and trays. These coatings are resistant to environmental factors like UV, moisture, and chemicals, and help maintain cable functionality during a fire. They are suitable for indoor and outdoor applications, including industrial plants, hospitals, and power stations.

Installation Considerations

Measure cable tray dimensions and select the appropriate size and number of fireproofing units. Ensure gaps between firestop packs and cables do not exceed 1 cm². For large penetrations, install a fire-resistant backing plate before sealing.

Maintain accessibility for maintenance while ensuring a complete, crack-free seal. Verify that selected materials meet local fire safety codes and certifications (EN 1366-3, UL, ETA, CE marking). Using a combination of these materials ensures compliance with fire safety standards, prevents flame and smoke propagation, and maintains the operational integrity of cable systems during a fire.