Should flame-retardant cables be routed through fire cable trays

Yes, flame-retardant cables can and should be routed through fire-rated cable trays to enhance fire safety, provided proper installation and sealing practices are followed.

Purpose of Fire Cable Trays

Fire-rated cable trays are designed to support and protect cables while limiting the spread of fire. They are typically made from steel, aluminum, or coated materials with fire-resistant properties, and may include fire barriers to isolate different fire zones . Using these trays ensures that flame-retardant cables maintain their integrity during a fire, reducing the risk of fire propagation along cable runs .

Installation Considerations

1. Cable Routing and Spacing: Flame-retardant cables should be carefully routed along designated pathways, avoiding sharp bends, excessive tension, and contact with heat sources. Adequate spacing between cables is essential to prevent overheating and facilitate airflow .
2. Fire Stops and Seals: When cable trays pass through walls, floors, or ceilings, openings must be sealed with fire-rated penetration materials to maintain the integrity of fire-rated compartments . This prevents the spread of fire and smoke through penetrations.
3. Tray Type and Material: Select trays classified as non-flame propagating according to standards such as BS EN 61537. For high-risk areas, fireproof trays with coatings or fire-resistant materials are recommended .
4. Mechanical Support: Secure cables using appropriate clamps, ties, and fasteners to prevent movement, abrasion, or mechanical damage, which could compromise fire performance .

Regulatory Compliance

Standards such as BS 7671:2018 require that cables in protected escape routes or fire compartments meet flame-retardant criteria (e.g., BS EN 60332-1-2) and be installed in containment systems with resistance to flame propagation . Fire-rated cable trays are recognized as suitable containment for these purposes, ensuring compliance with building regulations and safety codes.

Additional Safety Measures

• Segregation of Cable Types: Power and signal cables should be routed separately to minimize interference and reduce fire risk .
• Regular Inspection: Periodically check trays for corrosion, coating integrity, and proper sealing to maintain long-term fire protection .
• Avoid Modifications: Do not damage or alter the tray structure or fireproof coating, as this can compromise fire containment .

Conclusion

Routing flame-retardant cables through fire-rated cable trays is recommended and compliant with fire safety standards, provided that proper installation, sealing, and maintenance practices are followed. This approach enhances fire containment, reduces the risk of fire propagation, and ensures the continued functionality of critical electrical systems during emergencies .