Fire Cable Tray Size Standards

Fire-rated cable trays are designed to maintain cable function during fire, with specific dimensions, banding, wraps, and compliance to ASTM and API fire standards. Standard DimensionsFire-rated cable trays follow standard dimensional ranges similar to conventional trays, including: Width: Typically 100 mm to 1220 mm, depending on cable load and application. Wider trays are used for high-density installations.

Depth: Varies from 25 mm to 150 mm or more, ensuring adequate cable support and heat dissipation. Length: Standard tray sections are usually 3 meters long, but custom lengths are available. Material Thickness: Commonly 0.

6 mm for corrugated aluminum sheeting used in fire protection, with stainless steel or galvanized steel for structural strength and corrosion resistance. Tray types include ladder, perforated, channel, and wire mesh, each with different depth and width considerations based on load, ventilation, and cable type. Fire Protection SpecificationsFire-rated cable trays, such as FireMaster®, include the following features: Wraps: Cable trays are wrapped with fire-resistant material, typically one layer with 75 mm thickness, with 50 mm overlap at joints.

Banding: Stainless steel banding straps, minimum 12 mm wide, are installed at 250 mm centers to secure the wrap and prevent slumping. Additional banding may be used at elbows and 90° bends. Mesh Lining: For open trays, mesh lining is used to support the wrap and maintain cable integrity during fire.

Weather Protection: Corrugated aluminum sheeting (0. 6 mm thick) may be used for outdoor installations. Fire Testing and StandardsFire-rated cable trays are tested to ensure performance under fire conditions: ASTM E1725-95: Measures response of electrical system components to heat or flame under controlled conditions.

AST

M E119 and E1529: Provide cellulosic and hydrocarbon fire curves for testing.

AP

I 2218: References ASTM E1725-95 for petroleum and petrochemical plant applications, using hydrocarbon fire curves equivalent to UL 1709. These standards ensure that cable trays maintain functionality, minimize toxic gas emission, and aid in safe evacuation during fire events.

Installation Considerations

Ensure tight banding at all tray edges and overlaps. Maintain maximum strap spacing of 250 mm in the center of the tray. Use additional banding at bends and elbows to prevent wrap displacement.

Select tray width and depth based on actual cable area and allowed fill percentage, typically 40% of usable tray area. By following these dimensions and specifications, fire-rated cable trays provide both structural support and fire protection, ensuring compliance with safety standards and long-term reliability.