Fire protection for metal cable trays involves using fire-resistant trays, firestop systems, and protective coatings to ensure cables remain functional during a fire.

Fire-Resistant Cable Trays

Metal cable trays designed for fire protection, such as Cablofil fireproof trays, are suitable for both low and high voltage cables. These trays are tested to stringent standards like DIN 4102-12, which subjects the entire tray system to temperatures up to 1000°C for 30, 60, and 90 minutes, ensuring fire resistance for critical installations in power, oil, gas, rail, and industrial sectors . Fireproof trays are often paired with special cable cleats to maintain cable integrity under fire conditions.

Firestop Systems

When cable trays pass through fire-rated walls or floors, firestop systems are essential. Products like 3M Fire Barrier Moldable Putty+ or 3M pillows can seal openings around trays, preventing fire and smoke propagation. The number of firestop elements depends on tray size and wall type, with UL-listed systems providing specific F-Rating and T-Rating for concrete or gypsum walls . Intumescent caulks, such as IC 15WB, expand under heat to block fire penetration and protect structural steel and cables.

Fire Protection Coatings and Tapes

For additional protection, fire-resistant coatings and tapes like FLAMMOTECT-A and DG-CR 0.7 can be applied directly to cables within trays. These solutions prevent flame propagation, enhance resistance to environmental factors (UV, moisture, chemicals), and maintain cable functionality during a fire . They are suitable for indoor and outdoor applications, including high-risk areas like hospitals, substations, and offshore facilities.

Installation Guidelines

Proper installation is critical for fire safety:

• Tray Material Selection: Use painted or galvanized steel for indoor, hot-dip galvanized or stainless steel for outdoor, and aluminum or fiberglass-reinforced trays in corrosive environments .
• Mechanical Strength: Ensure trays can support full cable load without deformation.
• Alignment and Leveling: Horizontal deviation ≤2mm/m, vertical deviation ≤3mm/m; trays must be level, plumb, and securely mounted .
• Segregation: Separate high-voltage power cables from low-voltage signal cables to reduce interference and fire risk.

Summary

To protect incoming lines in metal cable trays:

1. Use fireproof or fire-resistant trays tested to recognized standards.
2. Apply firestop systems at wall and floor penetrations.
3. Consider fire-resistant coatings or tapes for additional cable protection.
4. Follow installation standards for material, alignment, and segregation to maintain safety and compliance. These measures ensure that cable systems remain operational during a fire, minimize damage, and comply with fire safety regulations.