Since the discovery of fire, humans have been taking steps to protect themselves from fire’s harmful effects. Cables in communication applications are not exempt from catching fire and can produce harmful smoke and gas, so preventative measures have been taken to make sure that cables are safe too – hence, the development of LSZH cables.
Low-Smoke Zero-Halogen (LSZH) refers to the material in the cable’s outer jacket. Most commercially available cable assemblies have an outer jacket made from polyvinyl chloride (PVC). PVC is a durable, flexible plastic that is perfect for most applications, but one of the biggest downfalls of PVC is the way it burns. Once PVC has caught fire, it typically burns freely for a long time and releases toxic gas in the process. On the other hand, LSZH cable jacketing is made of thermoplastic or thermoset compounds that emit limited smoke, no halogen and won’t produce dangerous gas when exposed to high sources of heat.
In a building fire, there is a danger of standard PVC cables burning behind the walls or in ceilings for a long period of time and that fire spreading from room to room or floor to floor and creating toxic gasses. Though in most building fires, occupants are able to evacuate and escape these gasses, but sometimes getting out of the building isn’t an option.
LSZH cable jackets are becoming increasingly popular in applications where people are in close proximity to cable assemblies and cannot easily get ventilation in the event of a fire, such as military, aerospace, railroad and maritime applications. Cost effective LSZH jackets are typically used, and sometimes required, in poorly ventilated areas such as onboard aircraft, military vehicles, submarines and ships. They are also used extensively in railway systems, wherever high voltage or track signal wires are run through underground tunnels. This reduces the chance of toxic gasses accumulating in these areas if the cables caught on fire.
In the event of a fire, an LSZH cable jacket can be instrumental in protecting people from fire, smoke and dangerous gas emitted from the burning cables. L-com offers a wide-range of LSZH cable assemblies thatare designed for use in areas where toxic smoke could damage sensitive equipment and enclosed areas where air quality is a concern. For more information, check out our LSZH cable assembly product guide.
