Should flame-retardant cables be routed through fire cable trays

Flame-retardant cables can be routed through cable trays, but fire-rated trays are not strictly required unless the installation demands fire containment or segregation.

Understanding Cable Types

Flame-retardant cables are designed to limit flame propagation and prevent fire from spreading to other areas, but they do not maintain electrical operation during a fire . In contrast, fire-resistant cables are intended to continue operating under fire conditions, which is critical for life-safety systems like fire alarms or emergency lighting . Therefore, the choice of cable type determines the need for additional fire-rated containment.

Cable Tray Considerations

Cable trays can be classified as non-flame propagating or fireproof according to standards such as BS EN 61537 . Fire-rated trays are primarily used to:

• Contain flames and smoke within a compartment
• Isolate different fire zones
• Protect critical circuits that must remain operational during a fire For flame-retardant cables, the main goal is to prevent fire spread, not to maintain power. Therefore, routing them through standard non-flame-propagating trays is generally acceptable. Fireproof trays are recommended only if:
• The installation passes through walls or floors requiring fire-rated penetration sealing
• There is a need to segregate cables to prevent fire propagation between zones
• Local regulations or building codes mandate fire-rated containment for all cables in certain areas

Installation Best Practices

• Maintain adequate spacing between cables to reduce heat accumulation and allow airflow .
• Use fire barriers within trays to isolate different fire zones if required.
• Ensure mechanical integrity of trays to prevent collapse during fire or under load.
• Seal tray penetrations through walls or floors with fire-rated materials.
• Perform routine inspections to check for corrosion, damage, or compromised fireproof coatings .

Summary

While flame-retardant cables do not require fire-rated trays for their primary function, using fire-rated or non-flame-propagating trays can enhance safety by limiting fire spread. Fire-rated trays are essential for circuits that must remain operational during a fire, but for general-purpose flame-retardant cables, standard trays with proper installation and segregation are typically sufficient . Compliance with BS 7671 and local building regulations should always guide the final installation choice .