What are halogens?
Elements such as fluorine, chlorine, bromine, iodine, and astatine are halogens and appear in the seventh main group of the periodic table of elements. They are found in many chemical compounds, for example in polyvinyl chloride. PVC, as it is known for short, is very durable, which is why it is used in many technical products, as well as insulation material and pipe sheathing. Chlorine and other halogens are often included as additives to improve flame protection. But that comes with a price. Halogens are harmful to health. For this reason, halogen-free plastics are increasingly used for cables.
What is a halogen-free tube?
As the name suggests, halogen-free tubes do not contain halogens in the composition of the plastics. Halogen-containing plastics can be identified by the chemical elements in their names, such as the aforementioned polyvinyl chloride, chloroprene rubber, fluoroethylene propylene, fluoropolymer rubber, etc. If you want or need to use halogen-free tubes, make sure they consist of from plastic materials such as silicone rubber, polyurethane, polyethylene, polyamide, polypropylene, thermoplastic elastomers (TPE) or ethylene propylene diene rubber. They contain no heavy metal-based stabilizers or softeners, and flame-retardant additives are environmentally safe.
Why are halogen-free tubes important for fire protection?
Halogens can be harmful to health. This is especially the case when halogenated plastics, especially PVC, burn. If a fire breaks out, hydrogen halides are released from the plastic. Halogens combine with water, such as firefighting water or the fluid in mucous membranes, to form acids - chlorine becomes hydrochloric acid, fluorine the highly corrosive hydrofluoric acid. In addition, a mixture of dioxins and other highly toxic chemicals can form. If they enter the respiratory tract, they can cause damage and cause suffocation. Even if someone survives the fire, their health can be permanently damaged. This is even less the case with halogen-free tubes. For integrated fire protection, the tubes should also have flame protection and low smoke generation. Flame protection slows combustion and flame propagation and promotes self-extinguishment. Manufacturers face a dilemma here because chlorine and bromine are excellent flame retardants, which is why they are often mixed with tubing plastics. However, due to the health hazards mentioned, this is controversial and is only allowed where no person is in danger.
What is the advantage of halogen-free tubes?
If halogen-free tubes are strongly heated or burned, they form much less acids or corrosive gases that are harmful to health. HF tubes are particularly suitable for use in public buildings, transport or generally where fires can seriously injure people or animals or damage property. They have a low density of flue gases, so they produce less smoke and make it easier for trapped people to find escape routes. Halogen-free tubes are particularly useful if you want to guarantee the maximum possible functional retention in the event of a fire. This can be important in buildings where surveillance cameras provide images of the fire source.