Halogen-free Cables

Halogens are the elements as flourine, chlorine, bromine and iodine. They are the most widely used raw materials for the PVC insulation cable and sheathing raw material. The main reason that make them so widely used are their low prices. PVC(Polyvinylchloride) is not halogenfree material that has a chloride in its molecular structure. In the case of a fire the cable insulation and the outer sheath material easily burn and the fire progress rapidly.

It causes the release of toxic and corrosive gases during the fire. The released chlorine atoms composite themselves with hydrogen which is decomposed from plastic material as well as with hydrochloric acid from the existing air which in turn causes events with the resulting deads of humans and animals in the indoor environments. As for the corrosive gases they cause to wear, rust and deteriorate of the surface of metals. The density of smoke is increased because it releases black and dark smoke. The increase of density is in turn prevents the fire extinguishing works while everwhere is covered with a dark, black smoke.

Halogenfree compounds are used in order to overcome the mentioned disadvantages of PVC. These compounds contain considerable percentage of flame protective materials. These halogenfree materials are composed with polymers on the basis of pure hydrocarbons used as the insulation and sheath materials of cables. By burning such kind of materials produce no corrosive and toxic gases but only water vapour and carbondioxide. Halogenfree cables are hardly flammable and self extinquishing.They do not release dark and black smoke. They have such protective materials for example of an aluminium hydroxide which on one side cools the fire location by setting free of crystal water and on the other side the released water vapour hinders the admittance of oxygen and thereby this suffocates the flame. By using of additional supporting tapes and filling yarns of glass web, mica and similar materials the funtionality for example of E 90 can be realized with the suitable cable accessories.

The application of halogenfree cables are specified more and more with increasing numbers for the building where people gather where safety conciousness to protect the human life and valuable materials take a special significance.

The application areas of halogenfree are shortly as follows :

●   Hospitals,airports, in multi story buildings, stores and shopes, hotels, theatres, cinemas, schools etc.

●   Fire warning plants, alarm systems, ventilation systems, escalators, lifts, safety lights, maintenance equipment.

●   Underground railways and other railway plants

●   Data processing installations

●   Power stations and industrial plants with high valuable machines and materials or risky potentials

●   Mining Works

●   Shipbuilding and offshore plants

●   Emergency power supply Works

The summary features of the halogenfree cables are as foollows:

●   Flame retardant and difficult to burn so no flame propagation in case of fire can be resulted.

●   Halogenfree, no evolution of corrosive gases.

●   During the course of a fire the halogenfree cables emit low smoke.

●   The risk of poisonous gases the danger of toxic gases caused by fire is far inferior

●   Low caloric load

●   Remarkable longer electrical functionality and flame influence

The characteristics of halogenfree cables regarding their behaviour in fire can be tested according to VDE 0472 part 804 as well as tested in 3 different test methods. These are classified as Test A , Test B, Test C.