Fire protection duration for large-span cable trays in North Macedonia

Large-span cable trays typically require fire protection ensuring 30 to 120 minutes of fire resistance, depending on building type, occupancy, and applicable European standards.Fire Resistance RequirementsIn industrial and commercial environments, cable trays must maintain circuit integrity during a fire to ensure power and communication systems remain operational. Fire protection duration is generally expressed in minutes (e.g., 30, 60, 90, or 120 minutes) and depends on:Building occupancy and risk level: Hospitals, airports, and power stations often require higher fire resistance (up to 120 minutes) compared to standard commercial buildings (30–60 minutes) .Cable type and load: High-voltage or critical communication cables may require longer protection.Tray span and support: Large-span trays need robust fire-resistant coatings or fireproof enclosures to prevent collapse under fire conditions .Fire Protection MethodsFire-Resistant Coatings and Tapes: Products like FLAMMOTECT-A and DG-CR 0.7 form a protective shield around cables, preventing flame propagation and maintaining functionality during fire .Fire-Resistant Cable Supports: Supports must be made of materials that do not fail under fire, ensuring the tray remains suspended and cables intact .Enclosures or Fireproofing Panels: For large spans, enclosing trays in fire-rated ducts or panels can achieve the required fire resistance duration.Installation ConsiderationsTray Material: Steel, galvanized steel, or aluminum alloy trays are preferred for fire resistance. Fiberglass-reinforced plastic may be used in corrosive environments but requires additional fireproofing .Support Spacing: Proper support intervals prevent sagging or collapse during fire. The spacing depends on cable weight, tray width, and material stiffness .Segregation: Power and signal cables should be separated to reduce fire risk and maintain system integrity .Standards and GuidelinesWhile North Macedonia may adopt European standards (EN 1366-3, EN 50200) for fire resistance testing of cable systems, the Standard Fire Curve ETK is often used to model fully developed fire conditions for design purposes . Fire protection duration should be selected according to these standards and the criticality of the installation.Practical RecommendationFor large-span cable trays in high-risk or critical facilities, a minimum of 60 minutes fire resistance is recommended, with 90–120 minutes for hospitals, power plants, or emergency systems. Fireproof coatings, fire-resistant supports, and proper tray design are essential to achieve these durations. Regular inspection and compliance with EN standards ensure reliability and safety.