Thickness of fire cable trays

The thickness of fire-rated cable trays depends on the material, load requirements, and fire protection standards, typically ranging from 1.2 mm to 3 mm for steel trays, with additional fireproofing wraps applied as needed.

Material and Thickness Considerations

Fire-rated cable trays are commonly made from painted steel, galvanized steel, stainless steel, or aluminum alloys, depending on the environment and exposure conditions . The tray thickness must be sufficient to support the weight of the cables and prevent deformation under full load. For standard steel trays, thicknesses generally range from 1.2 mm to 3 mm, with heavier-duty trays used for larger cable bundles or higher mechanical stress . Aluminum trays may have slightly different thicknesses due to material strength differences.

Fireproofing Measures

To achieve fire resistance, cable trays can be wrapped with fireproof materials such as the FireMaster Cable Tray Wrap, which uses high-temperature fibers and aluminum foil to protect cables during fire exposure . The wrap is installed with minimum overlaps of 75 mm (3 in) and secured with stainless steel bands at minimum 262 mm (10-1/2 in) centers, ensuring the tray maintains structural integrity and cable protection during fire events .

Design and Installation Guidelines

When selecting tray thickness, consider:

• Number and weight of cables: Heavier loads require thicker trays .
• Environmental conditions: Corrosive or high-humidity areas may require stainless steel or aluminum with appropriate thickness .
• Fire rating requirements: Fireproof wraps or coatings may allow standard tray thicknesses to meet fire resistance standards .
• Mechanical strength: Ensure trays do not deform under full load; horizontal deviation should be ≤2 mm per meter and vertical deviation ≤3 mm per meter .

Summary

For fire-rated cable trays, steel trays typically range from 1.2 mm to 3 mm in thickness, with additional fireproofing wraps applied to meet fire safety standards. The exact thickness should be selected based on cable load, environmental conditions, and fire protection requirements, ensuring both mechanical stability and compliance with safety regulations .