What defines Low Smoke Zero Halogen (LSZH) cables, and what advantages do they offer in enclosed environments?

Q: What defines Low Smoke Zero Halogen (LSZH) cables, and what advantages do they offer in enclosed environments?

A: LSZH cables—also referred to as Low Smoke Free Halogen (LSFH) cables—are specialized wiring solutions designed with thermoplastic or elastomeric materials that emit minimal smoke and zero halogen gases when exposed to high temperatures or fire. Unlike traditional PVC cables, which release toxic hydrogen chloride gas (causing respiratory hazards) and dense smoke (impairing visibility), LSZH variants utilize halogen-free compounds such as polyethylene or polypropylene blended with metal hydroxides (e.g., aluminum trihydroxide) as flame retardants.

These cables provide three critical benefits in enclosed spaces like buildings, tunnels, and public transport: 1) Reduced smoke density (<0.1 optical density at 4 minutes per IEC 61034) for improved evacuation visibility; 2) Elimination of corrosive halogen acids (pH >4.3 per EN 60754-2) to prevent damage to equipment and infrastructure; 3) Lower toxicity levels (LC50 >50% v/v for 30-minute exposure) to enhance occupant safety during fire emergencies.