Waterproofing of Vertical Shaft Cable Trays

Vertical shaft cable trays can be effectively waterproofed using modular sealing systems, silicone-based sealants, or pressure-fit seals designed for watertight penetrations.

Key Methods and Systems

1. Modular Sealing Systems Modular systems like Roxtec transits or CSD NOFIRNO® units provide flexible, watertight solutions for vertical cable tray penetrations. These systems use expandable rubber inserts or water-resistant pads that conform to cable shapes and sizes, allowing for future cable additions or changes without compromising the seal . Roxtec solutions are suitable for underground or high-moisture environments, resisting constant water pressure and ensuring operational reliability . 2. Silicone-Based Sealants For vertical penetrations, flowable silicone sealants such as Dow Corning 734 can be used to create a watertight barrier around cables. This method involves building a containment dam around the penetration and filling it with silicone, which flows into all crevices and cures to form a durable seal . 3. Pressure-Fit Seals Individually sealing cables with pressure-fit plugs is another effective approach, especially for vertical runs exiting pull boxes or concrete shafts. This method ensures a tight seal around each cable, minimizing water ingress even in challenging vertical configurations . 4. Weatherstop Frames Steel frames with water-resistant pads and silicone coatings, such as CSD WSP weatherstops, can be installed around cable trays at wall or floor penetrations. These frames are corrosion-resistant, suitable for outdoor or wet environments, and allow easy cable maintenance without additional parts .

Installation Considerations

• Orientation: Horizontal-to-vertical transitions are easier to seal than straight vertical penetrations; using a 90° bend can improve watertight performance .
• Joint-Free Application: Fibre-reinforced cold-applied liquids can be used to create joint-free seals that prevent leaks and thermal breaks, adaptable to any cladding or building system .
• Future-Proofing: Modular systems allow for cable additions or replacements without compromising the waterproofing .
• Environmental Resistance: Ensure materials are rated for submersion, UV exposure, and chemical resistance if the shaft is exposed to harsh conditions .

Best Practices

• Conduct pre- and post-installation checks to verify watertight integrity.
• Coordinate with structural and fire safety requirements; some systems also provide fire-rated protection .
• Consider custom-built frames or transits for complex arrays of cable trays to ensure structural stability and complete waterproofing .
• Use non-toxic, halogen-free materials for safety and compliance in industrial or marine environments . By combining modular sealing systems, silicone-based sealants, and proper installation techniques, vertical shaft cable trays can achieve reliable, long-term waterproofing while allowing for maintenance and future cable modifications.