IEC 60332-3-24:2018

Overview

IEC 60332-3-24:2018 is an international standard from the International Electrotechnical Commission (IEC) focused on fire testing for electric and optical fibre cables. It specifically defines the requirements and procedures for evaluating the vertical flame spread of vertically-mounted, bunched wires or cables-classified as Category C-under controlled conditions. The standard applies to both metallic conductor and optical fibre cables and is intended primarily for type approval testing. Category C is designed for general-use scenarios where assessing the fire performance of cables with low volumes of non-metallic material is necessary.

Key Topics

• Scope of Application: IEC 60332-3-24:2018 applies to wires and cables mounted on the front face of a standard test ladder with a nominal total volume of non-metallic material equal to 1.5 litres per metre of test sample.
• Test Procedure: The vertical flame spread test uses a propane ribbon burner applied for 20 minutes. The extent of damage-flame spread-is measured from the point of ignition.
• Sample Mounting: The standard specifies mounting configurations based on cable type. Cables with any conductor larger than 35 mm² are mounted spaced apart; smaller conductor and optical fibre cables are mounted in a touching configuration, both on the front of the ladder.
• Performance Evaluation: After flame application and extinguishing, the spread of char is measured as the critical criterion. The recommended maximum extent of flame spread is 2.5 metres above the burner base.
• Type Approval Testing: The document is primarily for type approval, providing guidance on cable selection and detailed test reporting requirements.
• Retest Procedures: In case of disputed failures, the standard outlines a clearly defined retest process, including sample selection and construction equivalency.
• Technical Revisions: The latest edition emphasizes applicability to optical fibre cables and clarifies mounting details for improved repeatability and reproducibility.

Applications

IEC 60332-3-24:2018 is widely relevant in industries requiring robust fire safety for wiring and cabling systems, including:

• Construction and Building Services: Used in selecting and certifying cables for commercial, residential, and public buildings to ensure compliance with fire safety codes.
• Telecommunications and Data Centers: Helps assess the fire performance of large bundles of communication and optical fibre cables installed in vertical risers.
• Industrial Facilities: Ensures cable safety in plants, refineries, and manufacturing environments where strict fire containment standards are critical.
• Transportation Infrastructure: Supports safety testing for cables used in tunnels, subways, and stations, reducing flame propagation risk in confined spaces.

By adopting IEC 60332-3-24:2018, manufacturers, installers, and certifiers can demonstrate compliance with international fire safety expectations for bundled cable installations.

Related Standards

For comprehensive fire testing and safety verification, consider these closely related standards:

• IEC 60332-1 & IEC 60332-2: Test methods for flame spread on single insulated wire or cable.
• IEC 60332-3-10: Specifies the test apparatus for vertical flame spread testing.
• Other IEC 60332-3 Categories: Parts 3-21, 3-22, 3-23, and 3-25 define tests for other cable categories (A, B, D) based on non-metallic volume and mounting.
• IEC 60811-606: Test methods for determining the density of non-metallic materials in cables.

Summary

Adherence to IEC 60332-3-24:2018 ensures that electric and optical fibre cables can be reliably assessed for their ability to limit flame spread when bunched in vertical installations. This supports safer cable product development, verified compliance in fire-critical applications, and alignment with global best practices in cable fire testing and certification.