Fireproof partition for cable trays in underground trenches

Fireproof partitions in underground cable trenches are designed to compartmentalize sections, prevent fire propagation, and maintain safe operation of power and communication systems.

Purpose and Importance

Fireproof partitions, also called fire-blocking sections or fire sections, are installed in cable trays and underground trenches to isolate fires, prevent fire spread, and protect critical infrastructure. They are essential in high-risk environments such as power plants, substations, and industrial facilities, where equipment aging, short circuits, or external fire sources can trigger fires. Properly implemented partitions enhance the disaster resilience of power systems and reduce potential casualties and property losses.

Materials for Fireproof Partitions

Several materials are commonly used for fireproof separation of cable trays in underground trenches: Fireproof boards: Provide strong fire resistance and prevent fire spread; however, they are heavy and occupy space, which may affect cable maintenance. Fireproof coatings and caulks: Intumescent coatings or firestop caulks can be applied to cable trays and walls to contain fire and smoke. They are easy to install and maintain, and allow heat dissipation.

Fireproof bags or mud: Lightweight and convenient for construction, but may require regular maintenance due to lower durability. Light fireproof sections: Modern alternatives offering easy installation, excellent fire performance, and good heat dissipation, suitable for adding or replacing cables. Fire-resistant mineral wool or firestop packs: Used to fill gaps around cables and maintain compartmentation, ensuring no voids exceed 1 cm².

Design and Installation Considerations

Compartmentation: Underground trenches should be divided into sections using transverse barriers to limit fire spread along the cable route. Access and maintenance: Barriers can include personnel doors or demountable panels to allow safe maintenance without compromising fire protection. Penetration sealing: Any services passing through partitions must be firestopped using appropriate seal systems to maintain the overall fire rating.

Fire rating: Materials and partitions should meet UL or equivalent fire ratings, ensuring they withstand fire for the required duration while protecting cables. Gap management: Gaps between firestop packs and cables should be minimal, typically less than 1 cm², with packing thickness not less than 24 cm for slab penetrations.

Maintenance and Long-

Term Performance

Regular inspection is necessary to ensure fireproof materials remain intact and effective. Some materials, like fireproof boards, may require repainting or replacement over time, while modern light fireproof sections and intumescent coatings offer long-term durability with minimal maintenance.

Summary

For underground cable trenches, fireproof partitions are critical for safety and operational reliability. Selecting the right combination of fire-resistant boards, coatings, packs, or modern light sections, along with proper compartmentation, penetration sealing, and maintenance, ensures effective fire containment while allowing access for cable installation and maintenance.