Spacing of fireproof partitions for cable trays

Fireproof partitions for cable trays are typically installed at intervals of 3 to 5 meters, or where fire-rated barriers are required, with a minimum horizontal separation of 300 mm between parallel trays when barriers are impractical. General GuidelinesFire-blocking sections or fireproof partitions are installed along cable trays to prevent the spread of fire, protect circuits, and ensure safe operation of electrical systems in industrial and commercial environments. The spacing of these partitions depends on factors such as cable type, fire rating, and installation environment.

Typical spacing: Fireproof partitions are generally placed every 3 to 5 meters along the cable tray run, especially in long horizontal or vertical runs, to limit fire propagation. Parallel trays: When two cable trays run in parallel, a minimum horizontal air gap of 300 mm is recommended if fire-rated barriers are not used, based on UK guidance (BS 8519, BS 5839) for life-safety circuits. Vertical spacing: For floor-to-ceiling or multi-tier installations, maintain at least 150 mm vertical clearance between trays to allow airflow, heat dissipation, and access for maintenance.

Fire-rated materials: Partitions should use fire-resistant boards, mineral wool, or firestop packs, with sealing thickness typically 20–30 mm at penetrations through walls or slabs.

Installation Considerations

Tray type and material: Use fireproof or fire-rated trays where flame containment is required. Ensure mechanical strength to support cable weight and prevent deformation. Circuit segregation: Power and signal cables should be separated either by distance (≥0.

5 m) or by barriers to reduce electromagnetic interference and maintain circuit independence. Maintenance access: Adequate spacing ensures technicians can inspect, maintain, or replace cables safely without compromising fire safety. Regulatory ReferencesBS 8519: 2020 – Recommends separation of primary and secondary life-safety circuits by fire partitions or a minimum 300 mm air gap.

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S 5839-1: 2020 – Suggests duplicate power supply cables should be segregated with at least 300 mm separation or by fire-resisting barriers. National standards – Fire-blocking sections must use materials stable under environmental conditions, including moisture and rodent exposure. By following these spacing and partitioning guidelines, cable tray installations can achieve effective fire containment, circuit protection, and compliance with safety standards.