Fireproof partition requirements for elevator cable trays

Elevator cable trays must pass through fire-rated partitions with properly installed fire-blocking sections that meet or exceed the fire resistance of the surrounding structure.Fire-Blocking Sections and PurposeFire-blocking sections, also called fire partitions, are installed along cable trays to prevent the spread of fire, protect structural integrity, and ensure safe operation of electrical systems in elevator shafts and other critical areas . These sections are particularly important in high-risk environments where short circuits, insulation failures, or external fire sources could ignite cables .Fire Resistance RatingsMinimum fire resistance: Fire-blocking components must have a fire resistance rating not lower than 1 hour and should match or exceed the fire rating of the wall, floor, or slab they penetrate .Material standards: Fireproof materials must comply with national standards such as GB23864 for fire-blocking materials, ensuring stability under high temperatures and resistance to burning, deformation, or cracking .Materials and InstallationApproved materials: Fire-rated boards, firestop packs, firestop mastic, intumescent caulks, and fire-resistant mineral wool are commonly used .Sealing requirements: Openings around cable trays must be tightly sealed without visible cracks or voids. For large openings, a fire-resistant backing plate should be installed before sealing .Packing and thickness: Firestop packs should be arranged in sequence, with gaps between packs and cables not exceeding 1 cm², and packing thickness typically not less than 24 cm .Elevator shaft specifics: At slab penetrations, provide 20–30 mm of firestopping and install a fire-support plate at the top. Floor-level cable trays should include a waterstop of at least 50 mm .Practical ConsiderationsDurability: Materials should withstand environmental factors such as water exposure or rodent damage .Accessibility: Layout and positioning must allow for maintenance and cable additions without compromising fire protection .Product examples: Moldable putty, intumescent caulks, and UL-listed firestop systems are recommended for retrofitting or new installations .SummaryTo ensure compliance and safety, elevator cable trays must pass through fireproof partitions with fire-blocking sections that are properly rated, sealed, and installed using approved materials. The fire resistance of these partitions should match or exceed the surrounding structure, and installation must prevent gaps, allow maintenance, and maintain long-term durability under operational conditions .