Vertical fireproofing of cable trays

Vertical cable trays must use fire-resistant materials, coatings, and firestop systems to prevent flame spread and maintain fire compartmentalization.

Material and Tray Selection

Vertical cable trays should be constructed from galvanized steel, stainless steel, or flame-retardant coated trays to ensure fire resistance and mechanical strength under load . For corrosive or high-humidity environments, aluminum alloy or fiberglass-reinforced plastic trays with fire-retardant properties are recommended . The tray width and thickness must support the cable weight and allow proper airflow to prevent overheating .

Fire-Resistant Coatings

Fireproof cable trays require specialized coatings to enhance heat resistance and slow flame propagation. The process includes:

• Cleaning and rust removal to ensure proper adhesion.
• Primer application with anti-corrosion and fire-resistant properties.
• Topcoat application for durability, weather resistance, and uniform finish.
• Inspection for coating thickness, adhesion, and uniformity to meet national fire safety standards .

Firestop Measures for Vertical Runs

When vertical cable trays pass through walls, floors, or slabs, firestopping is essential to maintain compartmentalization:

• Seal openings with fire-rated boards, firestop packs, firestop mastic, or mineral wool .
• Ensure tight, crack-free sealing around cables and trays.
• For large openings, install a fire-resistant backing plate before sealing .
• Maintain minimum packing thickness (typically ≥24 cm) and limit gaps between firestop materials to ≤1 cm² .
• Use cover plates to close openings, ensuring consistent dimensions and proper painting .

Installation Practices

• Maintain adequate clearance between cables to allow heat dissipation and prevent overheating .
• Use perforated or wire mesh trays to improve airflow along vertical runs .
• Avoid modifying or damaging the tray coating or structure during installation .
• Install fire barriers within the tray to isolate different fire zones if required .

Inspection and Maintenance

• Conduct routine inspections for corrosion, deformation, or coating degradation .
• Perform fire resistance checks periodically to ensure long-term effectiveness.
• Document all inspection results, including coating thickness, adhesion tests, and fireproofing compliance .

Summary

Vertical cable trays must combine fire-resistant materials, proper coatings, firestop systems, and careful installation to prevent fire spread. Compliance with national and international standards, along with regular inspection and maintenance, ensures both safety and operational reliability in commercial and industrial electrical installations .