Sealing the openings of cable trays in the computer room

Cable tray openings in computer rooms can be effectively sealed using firestopping materials, modular firestop systems, intumescent pillows, and cable entry seals to ensure fire, smoke, and environmental protection.

Firestopping Materials and Techniques

Openings where cable trays pass through walls, floors, or slabs should be tightly sealed with fire-rated materials to prevent the spread of fire and smoke. Common approaches include:

• Firestop boards and mineral wool: Install a fire-resistant backing plate for large openings, then fill gaps with fire-rated boards or mineral wool. Ensure all gaps around the cables and tray are sealed without visible cracks or voids, with packing thickness typically not less than 24 cm and gaps not exceeding 1 cm² .
• Firestop mastic: Applied around cables and tray edges to create a continuous seal, suitable for irregular shapes or small gaps .

Intumescent Fireproof Pillows

AF BAGS are intumescent and ablative fireproof pillows designed for cable tray penetrations. They expand under heat to seal openings and are certified for up to EI 240 fire resistance. Key features include:

• Non-combustible fiberglass casing with intumescent compounds and thermal insulators.
• Suitable for small to large cable penetrations, with a sealing depth of 120 mm for cables up to 21 mm in diameter.
• Easily repositioned for maintenance or future modifications .

Modular Firestop Systems

FIRSTO firestops provide a modular solution for multi-cable and cable tray penetrations:

• Simple to assemble around existing cable runs on walls or floors.
• Allows easy addition or removal of cables without compromising the firestop.
• Withstands heavy mechanical loads while preventing smoke and fire spread.
• Ideal for fire-rated walls and floors in computer rooms .

Cable Entry Seals

For high-density or flexible installations, cable entry seals offer a robust and adaptable solution:

• Roxtec entry seals use rubber modules with removable layers to fit various cable sizes, allowing spare capacity for future expansion .
• TE Connectivity Raychem CES are heat-shrinkable, water- and fume-tight seals for single or multiple cables, providing long-term environmental protection .
• These systems simplify installation, reduce material usage, and maintain operational reliability while allowing modifications.

Best Practices

• Measure cable tray dimensions accurately to select the appropriate sealing solution.
• Ensure all gaps are completely filled and seals are flush with wall or floor surfaces.
• Use fire-rated materials certified to relevant standards (e.g., EN 1366-3, EI 120/240).
• Plan for maintenance and future cable additions by choosing modular or repositionable systems. By combining firestopping materials, intumescent pillows, modular firestop systems, and cable entry seals, computer rooms can achieve compliant, reliable, and maintainable sealing of cable tray openings, ensuring both safety and operational flexibility .