Since the 1970s, fire-retardant, low-smoke zero-halogen (LSZH) wire and cable has been commercially available for shipboard applications, offshore marine platforms, rapid transit and similar applications where people are present in confined areas. When combined with other fire prevention and suppression practices, fire-retardant LSZH cables can minimize fire-related deaths and property damage. However, gases produced by all burning materials—whether LSZH or not—are extremely toxic. Several key advantages and disadvantages of LSZH cables are as follows :
LSZH wire and cable produce less smoke when burned, which permits people to exit a burning building more quickly and results in less soot damage to electronic equipment located near the fire.
Because LSZH releases little or no halogen gas when burned, it reduces the human respiratory system's damage if inhaled. It contributes to less corrosion damage to equipment near the fire.
LSZH jackets have a lower coefficient of friction than some non-LSZH jackets, which can make installation easier.
Because LSZH is more susceptible to jacket cracking caused by pulling lubricants or cable bending, special lubricants1 have been developed to minimize cable damage during installation.
LSZH jacket compounds usually have very high filler content (approx. 50%) to provide the required flame and smoke performance. As a result, most have poorer mechanical, chemical resistance, water absorption and electrical properties than non-LSZH compounds.
The current generation of LSZH cables has not yet established a proven history of long-term performance.
What are Halogens?
Although everyone is familiar with smoke, halogens are not as well understood. When present in a fire, halogens are a class of chemical elements that can form hazardous gasses. For the wire and cable industry, c