Fireproofing Construction Plan for Cable Trays

Fireproofing cable trays involves careful material selection, coating, firestop installation, and inspection to ensure fire resistance and compliance with safety standards.

1. Planning and Tray Selection

Begin by planning the cable tray layout to align with the building structure, minimizing unnecessary crossings and detours. Segregate power and signal cables using dedicated trays to reduce interference. Select tray materials based on the environment: painted or galvanized steel for indoor use, hot-dip galvanized or stainless steel for outdoor, and aluminum alloy or fiberglass-reinforced plastic for corrosive or high-humidity areas. Ensure tray width and thickness support the cable load and allow proper heat dissipation .

2. Surface Preparation and Coating

Clean the tray surface thoroughly to remove oil, dust, and rust. Rust removal can be done via sandblasting, acid washing, or grinding until a clean metallic shine is visible. Apply a primer with strong adhesion and anti-corrosion properties, followed by a fireproof coating using spraying, rolling, or brushing. Control the coating thickness to meet fire-resistance standards, and finish with a durable topcoat that is weather-resistant and smooth .

3. Firestop Installation

When cable trays pass through walls, floors, or slabs, seal openings with fire-rated materials such as firestop packs, firestop mastic, fire-resistant mineral wool, or fire-rated boards. Ensure gaps between firestop materials and cables do not exceed 1 cm², and maintain a minimum packing thickness of 24 cm. For large openings, install a fire-resistant backing plate before sealing. Waterstop platforms should be constructed in vertical shafts to facilitate effective sealing .

4. Layered Fire Blocking

Place fire blocking materials layer by layer, aligning with water stop platforms. Fill gaps between cables, trays, and fire blocking materials with fireproof mortar to create a compact, uniform barrier. Ensure protective steel plates are securely fixed, treated with anti-rust paint, and coated with fireproof material to prevent failure during a fire .

5. Heat Dissipation Considerations

Use perforated or wire mesh trays to improve airflow and maintain adequate clearance between cables to prevent heat accumulation. Proper spacing enhances both fire resistance and cable longevity .

6. Inspection and Maintenance

After installation, inspect the trays for coating quality, adhesion, and uniformity. Conduct tests such as cross-cut, pull-off, combustion, and endurance trials to verify fire resistance. Ensure tray connections are firm, aligned, and grounded. Perform routine cleaning and fire resistance checks to maintain long-term effectiveness .

7. Compliance and Documentation

Record all inspection data, including coating thickness, test results, and responsible personnel signatures. Store acceptance reports for future reference to ensure compliance with national safety standards and project specifications . By following these steps, cable trays achieve robust fire resistance, prevent flame spread, and maintain system safety in industrial and commercial installations.