What type of cable tray should be used for evacuation lighting

Evacuation lighting should be installed on non-flame-propagating cable trays or ladders made of metal or other non-combustible materials, compliant with BS EN 61537 and fire safety regulations. Key Considerations1. Fire Resistance and Material Evacuation lighting is a life safety system and must remain operational during a fire.

Cable trays should be non-combustible or not readily combustible, typically made of metal (steel or aluminum), to prevent fire propagation and maintain circuit integrity. Plastic or solely non-metallic supports are not acceptable as the sole means of support. Mineral insulated (MI) or LSZH fire-resistant cables are recommended for these circuits.

2. Compliance with Standards Cable trays must comply with BS EN 61537 for non-flame-propagating cable tray and ladder systems. This ensures that the tray itself does not contribute to fire spread.

Additionally, the installation should follow BS 7671 Chapter 42 requirements for fire protection, including limited smoke production to avoid inhibiting evacuation. 3. Segregation and Protection Evacuation lighting cables should be segregated from non-life-safety circuits to prevent interference and damage.

Shared containment is only allowed with earthed metallic dividers. Cables must be secured with metal fixings, and plastic clips or ties cannot be the sole support. 4.

Environmental Considerations For indoor or humid environments, ventilated or ladder-type trays are preferred to prevent moisture accumulation. Solid-bottom trays may be used if EMI/RFI shielding is required, but weep holes should be provided to avoid water retention. 5.

Installation Practices

Support spacing should follow manufacturer recommendations and standards (e.g., NEMA VE-1/VE-2 for ladder trays). Avoid sharp bends; maintain minimum bending radii for cables. Ensure trays are accessible for inspection and maintenance without obstructing escape routes.

Recommended Tray Types for Evacuation Lighting

Metal ladder trays (steel or aluminum) with non-flame-propagating classification. Ventilated trays to allow heat dissipation and reduce moisture accumulation. Solid-bottom trays only if EMI/RFI shielding is required, with proper drainage.

Non-combustible supports and metal fixings to secure cables. By following these guidelines, evacuation lighting circuits will remain operational during fire events, comply with UK and European standards, and provide safe egress for building occupants.