Acronyms for low smoke zero halogen / halogen free include LSZH, LSHF, LS0H & 0HLS. All these terms are interchangeable but we will use LSZH in this explanation.
LSZH cables are increasingly recommended for use in public buildings for increased fire safety in comparison to traditional PVC (polyvinylchloride) sheathed cables.
LSZH is often confused with LSF (low smoke & fume) but they are really very different!
What are halogens?
Standard PVC is made up of a significant number of halogens which when burnt produce toxic gases including hydrogen chloride (HCL). Hydrogen chloride is extremely dangerous and corrosive, capable of causing serious harm to people and equipment. It can even be compared to mustard gas which is used as a chemical weapon. Standard PVC can produce around 28% HCL emissions if burnt.
What is LSF cable?
The term LSF only indicates that the cable offers reduced smoke emission / fire propagation compared with standard PVC, often cable sold as LSF will just have a modified PVC sheath. There is no standard governing the HCL emissions of LSF cable but it will often produce between 18-22% HCL emissions when burnt which is still extremely hazardous.
What is LSZH cable?
The term zero halogen (interchangeable with halogen free) guarantees that if burnt the cable will produce less than 0.5% HCL (hydrogen chloride) emissions. The standard sheathing material is fairly tough & flexible with resistance to a wide range of oils & chemicals.