Technical paper: “Ensuring fire ratings when routing large cables” 

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Fire barriers are critical for a building’s passive fire protection. When cables or pipes are routed through fire-rated floors or walls, fire penetration seals are required to make sure the original fire rating is maintained. Penetration seals are rigorously tested to ensure integrity and insulation performance and compliance with established standards.

Martin Robertsson, Test and Certificates Manager at Roxtec, shares insights and practical recommendations from fire tests with large power cables and Roxtec seals with industry professionals during the fire safety conference “Brannforum” in Norway.

Fire tests with large power cables

Cables with outer diameters greater than 80mm fall outside the standard testing scope. Therefore, we launched a testing campaign to assess the effectiveness of our seals. Fire tests were performed with various types of power cables, including cables with aluminum and copper core materials as well as cables with varying conductor cross-sectional areas and different outer diameters. The objective was to achieve a fire performance rating of two hours, targeting the EI 120 classification.

Achieving EI 120 classification

The test results prove that all the assemblies achieved the EI 120 fire performance rating when installed in a concrete structure. Our seals demonstrated their reliability by maintaining both their shape and sealing capability, with no evidence of integrity loss, even when subjected to elevated temperatures of up to 1 050 °C at the end of the test. We note that insulation requirements are mainly driven by the cable itself, not by the sealing system.

Download our technical paper to explore insights from real‑world fire tests on large power cables.