Fire-retardant partitions (fire sections or fire-blocking sections) are essential for isolating cable trays to prevent fire spread, using materials like firestop packs, intumescent caulks, mineral wool, and mechanical firestop devices.

Purpose and Importance

Fire-retardant partitions, also known as fire sections or fire-blocking sections, are installed along cable trays to effectively isolate fires, prevent fire propagation, and ensure safe operation of power and industrial facilities. They are critical in high-risk environments such as substations, industrial plants, hospitals, and high-rise buildings, where cable fires can compromise safety and continuity of operations . These partitions also enhance the disaster resilience of electrical infrastructure and reduce potential property damage and casualties .

Materials Used

Common materials for fire-retardant partitions include:

• Firestop packs and pillows: Moldable, UL-listed products like 3M Fire Barrier Moldable Putty+ can seal openings around cable trays and conform to irregular shapes .
• Intumescent caulks: Latex or water-based caulks expand under heat to seal gaps and prevent fire and smoke spread, such as IC 15WB Caulk .
• Fire-rated boards and mineral wool: Provide structural fire resistance and are often used in combination with mechanical devices .
• Mechanical firestop devices: Systems like EZ-Path grommets allow easy installation around individual or bundled cables without sealants, providing up to two hours of fire resistance .
• Fire protection coatings and tapes: Products like FLAMMOTECT-A and DG-CR 0.7 form a protective shield around cables, preventing flame propagation and maintaining cable functionality during a fire .

Installation Guidelines

• Placement: Fire partitions should be installed at regular intervals along cable trays, especially near wall or slab penetrations, control rooms, or distribution devices .
• Sealing: All gaps around cables and trays must be tightly sealed, with no visible cracks or voids. For large openings, a fire-resistant backing plate should be installed before sealing .
• Thickness and spacing: Firestop packs should maintain a minimum thickness (e.g., 24 cm) and gaps between packs and cables should not exceed 1 cm² .
• Retrofit and maintenance: Many firestop systems, including mechanical devices and moldable putty, allow for easy retrofitting and reuse when adding or removing cables .

Compliance and Ratings

• Fire-retardant partitions must comply with UL-listed systems and local fire codes, providing specified F-ratings (fire resistance) and T-ratings (temperature rise) depending on wall or slab type .
• Typical ratings include 3-hour F-rating for concrete walls and 1–2 hour F-rating for gypsum walls, ensuring adequate protection in case of fire .

Summary

Implementing fire-retardant partitions along cable trays is a critical safety measure. Using a combination of firestop packs, intumescent caulks, mineral wool, and mechanical devices, and following proper installation guidelines ensures fire isolation, regulatory compliance, and operational safety in industrial and commercial electrical installations .