Fireproof board requirements for sealing cable trays

Cable tray penetrations must be sealed with fire-rated boards or equivalent firestopping materials, ensuring tight, crack-free installation with appropriate fire-resistance ratings.

Material Selection

Fireproof boards used for sealing cable trays should be fire-rated and compatible with the installation environment. Acceptable materials include fire-rated boards, firestop packs, firestop mastic, and fire-resistant mineral wool. For large openings, a fire-resistant backing plate should be installed before sealing to provide structural support and ensure complete fire containment . The boards must adhere to the required fire-resistance rating, typically S 30, S 60, or S 90, depending on building codes and compartmentation requirements .

Installation Requirements

• Tight Sealing: All gaps around the cable tray must be sealed without visible cracks or voids. The gap area between firestop packs and cables should not exceed 1 cm², and packing thickness should be at least 24 cm for effective fire containment .
• Backing Plates: For slab penetrations, install a fire-support plate at the top and maintain 20–30 mm of firestopping material around the tray .
• Cover Plates: Use square, evenly painted cover plates to close openings, ensuring consistent dimensions and complete encapsulation .
• Tray Considerations: Only use fireproof trays for flame containment or isolation. Do not modify or damage the tray coating or structure during installation .

Fire-Resistance Ratings

• Concrete Walls: Fireproof boards and associated firestopping systems should meet 3-hour F-rating and 3/4-hour T-rating for concrete walls .
• Gypsum Walls: Ratings may vary from 1–2 hours F-rating and 0–1/2 hour T-rating, depending on the system used .
• UL Listed Systems: Use UL-listed firestop boards or pillows, such as 3M medium self-locking pillows, to ensure compliance with tested firestop systems .

Maintenance and Inspection

• Routine Checks: Inspect fireproof boards and sealing materials periodically for cracks, gaps, or degradation.
• Environmental Considerations: Ensure boards are suitable for indoor or outdoor conditions, including humidity, corrosion, and UV exposure .
• Retrofitting: Fireproof boards and firestop systems should allow for easy retrofitting if additional cables are added or modifications are required .

Summary

To properly seal cable trays with fireproof boards:

1. Select fire-rated boards or equivalent firestopping materials suitable for the environment.
2. Ensure tight, crack-free installation with proper backing and cover plates.
3. Comply with fire-resistance ratings according to wall or slab type.
4. Perform regular inspections and maintenance to maintain long-term fire protection . Following these requirements ensures that cable tray penetrations maintain structural fire integrity and comply with safety standards.