Latest version of flame retardant standard for buried optical cables

The latest flame retardant standard for optical cables, including buried installations, is IEC 60332-1-2:2025, complemented by ITU-T L.100 (2024) for duct and direct-buried applications.

IEC 60332 Series Overview

The IEC 60332 series defines tests for electric and optical fibre cables under fire conditions, focusing on vertical flame propagation. The key parts relevant to optical cables are:

• IEC 60332-1-2:2025: Specifies the procedure for testing single insulated optical cables against a 1 kW vertical flame, assessing their ability to resist flame propagation and self-extinguish once the flame source is removed .
• IEC 60332-3: Covers bundled-cable tests, simulating real-world installations where multiple cables are grouped, which is critical for assessing fire safety in dense cable runs such as risers or ducts . These standards are widely referenced in international product codes, including EU CPR Euroclasses and UL AWM styles, ensuring global comparability of flame retardant performance .

ITU-T L.100 (2024) for Buried Optical Cables

ITU-T L.100 (01/2024) provides detailed specifications for optical fibre cables installed in ducts, tunnels, or directly buried. It references IEC 60794-3-11 for outdoor cable construction and performance, including:

• Mechanical and environmental characteristics suitable for buried applications
• Test methods for flame retardancy, electrical continuity, and optical performance
• Updated performance criteria for duct and tunnel installations, ensuring compliance with fire safety requirements This recommendation ensures that buried optical cables meet both mechanical durability and flame retardant performance for safe deployment in underground or enclosed environments.

Practical Implications

For manufacturers and specifiers:

• Single-cable compliance: IEC 60332-1-2:2025 ensures that individual cables resist flame propagation.
• Bundled installations: IEC 60332-3 testing is essential for real-world safety, especially in ducts or risers where multiple cables are installed together.
• Buried cable applications: ITU-T L.100 (2024) provides additional guidance for duct and direct-burial installations, integrating flame retardant requirements with mechanical and environmental performance . By adhering to these standards, optical cables can achieve recognized fire safety certification and meet regulatory requirements for both indoor and buried installations.