How to seal trapezoidal cable trays

Trapezoidal cable trays can be effectively sealed using fire-rated pillows, modular sealing systems, or weatherproofing sealants to protect against fire, water, and environmental ingress.

Fire Protection Sealing

For fire-rated applications, intumescent cable tray pillows are commonly used. These are reinforced pillows filled with a fireproof sponge and intumescent material that expand up to three times their size when exposed to fire, filling gaps around the tray and preventing fire spread. They are designed to fit into the trapezoidal tray profile, can be secured with retention tags, and are removable for maintenance or cable additions. They provide up to 4 hours of fire protection and comply with European and British standards for building regulations (Envirograf) .

Modular Sealing Systems

Modular sealing systems, such as those from Roxtec, use rubber bodies with removable layers to adapt to different cable sizes. These systems are flexible, allowing for future cable additions or changes without compromising the seal. They protect against fire, water, gas, and other hazards, and can be installed in walls, floors, or ceilings. The modular design ensures a tight fit for trapezoidal trays and simplifies installation while maintaining structural integrity .

Weatherproofing and Environmental Sealing

For outdoor or exposed installations, weatherproofing sealants or GRP (glass-reinforced plastic) systems can be applied. These create a waterproof and windproof barrier around the tray, preventing ingress of moisture, dust, birds, or rodents. For vertical wall penetrations, weatherstop systems or duct-like enclosures can be used, while roof penetrations may require service risers and supporting structures to maintain a sealed environment .

Installation Tips

• Ensure the tray is clean and free of debris before applying any sealant or inserting pillows.
• Measure the trapezoidal tray accurately to select the correct size of pillows or modular seals.
• For fire-rated installations, follow manufacturer guidelines for spacing and retention to maintain certification.
• For weatherproofing, check that all joints and penetrations are fully sealed and compatible with the building envelope.
• Consider future cable additions by using modular or removable sealing solutions to avoid repeated modifications. By combining these methods, trapezoidal cable trays can be safely sealed against fire, environmental hazards, and structural risks, while allowing for maintenance and future cable routing.