Low smoke zero halogen, referred to as LSZH, LSOH, LS0H, LSFH and OHLS, is the material classification of wire sheath in the wire harness and cable assembly industry. The low-smoke halogen-free wire sheath is composed of thermoplastic or thermosetting which has low smoke emission when heated and does not contain halogen itself.
Most of the network wire coating layer is composed of polyethylene, polyvinyl chloride or thermoplastic polyurethane. In case of fire, chlorine-containing plastic will release toxic hydrogen chloride, and if it encounters water, it will produce hydrochloric acid. Low-smoke, halogen-free materials will not release hydrogen halides or other acids when on fire.
Low smoke zero halogen materials can reduce the toxic and corrosive gases produced when they burn. Low smoke zero halogen materials are often used in poorly ventilated environments like airplanes, train cars, or ships. Low smoke zero halogen materials are also commonly used in the railway industry, because there will be high-voltage lines or signal lines that transmit the location of the train below the railway. The use of low smoke zero halogenmaterials also reduces the accumulation of toxic gases when the is damaged by fire or short circuit.
For example, in the railway industry or shipbuilding industry, an important requirement is to protect people and equipment from contact with toxic and corrosive gases. In these occasions, low smoke zero halogen materials are required on the outer layer of wire harnesses and cable assemblies.