Franck Gyppaz, Nexans, presented the company’s range of cable PIN fire performance solutions including ceramifiable INFITTM. These generate a crack-free protection around the cable conductor core in fire which ensures electrical insulation. Nexans fire-rated cable solutions combine polyolefins, fillers and specific PIN additives in sheath – bedding – insulator systems to ensure cable flexibility during installation, maintenance of properties with ageing, electrical resistance and fire performance with low smoke – zero halogen (LSZH).
Developments in cable fire testing, intended to ensure that cable fire safety is increasingly representative of real-life fire dangers, include the introduction of CPR (Construction Products Regulation), with harmonised and demanding cable fire standards, applicable to unprotected cables and associated cable management systems (duct, tray, ladders…) and to standard cables in protective systems. The new European fire standards EN50577 requires fire testing of the cable at its rated operational voltage. This can imply testing at significantly higher voltages than in the past, so is much more demanding regarding maintenance of electrical insulation.
Franck Gyppaz explained the fire safety challenges for cables. Cables must ensure continuing of function (transmission of electrical current, data) during fire, for significant times, in order to ensure continuing operation of safety installations, alarm systems. This requires maintenance of both continuity and electrical insulation when subject both to fire heat and to mechanical stress, as installations will distort and move in fire. Cables must not propagate fire, as cables often cross walls and other barriers, are present in voids inaccessible to fire fighters and sprinklers. Finally, and importantly, cables must ensure low smoke emissions and low fire gas toxicity (Low Smoke Zero Halogen LSZH). Nexans uses PIN flame retardants to ensure these different performance demands.