Rapid urbanization has escalated the need for high rise buildings, malls, modern houses and offices, all of which depend on wires and cables. In conjunction, electrical fires have become a common phenomenon lately causing great loss of property and human lives. Thus, a big task is to make the facilities safer and secure by installing quality wire and cables.
Approximately 80% Cables are around us and most of the time not visible once they are installed. They link rooms and floors and go through the walls without interruption. In the event of a fire, cables can therefore be a vital vector of propagation of fire to the whole building through the cabling system. A fire mishap happens due to the usage of low quality insulation material. In the Fifties the average time from ignition of a fire to flashover was 15 minutes. Now fatal conditions can occur after three minutes. This change has come about because of the increase of plastics.
Cables account for approximately 90% of all the plastic materials in electrical engineering systems. A fire can cause the temperature of plastics in cables to increase radically. The heat that this generates can cause other materials to ignite. The main danger is, however, the production of combustion gases and smoke that are harmful to people and equipment. Breathing in hot combustion gases acutely and permanently harms the alveolar in the lungs. Toxic smoke and gases can also cause immense consequential damage.
Any cable used within public buildings should, as a minimum requirement, present no danger to the health of people or integrity of property through acid gas emissions during a fire. They should also be self-extinguishing, that is, not continue to burn once the source of fire is removed and neither should it propagate fire into new areas. Further, while burning – and of course everything will burn given the right conditions – the smoke produced should not impede escape by obscuring emergency lighting and exit signs.
Requirements for low smoke emissions, low generation of corrosive and toxic gases and low fire propagation characteristics have produced a rapidly growing market for Halogen-Free Flame Retardant (HFFR) & Fire Survival (FS) cables. These cables come with annealed bare copper or annealed tinned copper conductors. Having a double layer glass mica tape, for insulation these cables come with special linked polyethylene. The inner sheath comes with Halogen Free compound with galvanized steel wire which prevents spreading of fire.
The cables are specially designed for optimum cabling solutions under fire mishap by maintaining the circuit integrity for temperatures up to 6500C, 7500C and/or 9500C as per application requirements. The inner and outer sheaths are specially designed with halogen free compound which reduces emission of fumes and acid gases in the event of fire. Some of the benefits of HFFR and FS cables are:
• Low toxic fire gases
• Reduced smoke density
• Reduced personal and environmental damage
• Low flame propagation (in flame retardant)
• Reduced vision impairing smoke; No harm to individuals from halogenated acid gases; No harm to equipment and computers from halogenated acid gases.
• Burns to an ash and will not propagate flame
• Can be used in a broad range of demanding applications, easy to bend and install.
In addition to the above the Fire Survival (FS) cables also carry the following important benefits:
• Fire resistant to CWZ category, according to BS 6387
• Maintain circuit integrity for prolonged period of time in a fire situation
• Provides vital additional time to accomplish the evacuation of personnel, to contain and minimize the damage and to mount an effective firefighting operation.
The reduction of smoke and effluent gases is relevant to saving human lives and facilitating the rescue act that has got affected due to the use of low insulated cables. Going forward, we should encourage the use of Low Fire-Hazard cables thanks to their lower environmental impact at the end of their life cycle. The benefit is obviously even bigger when that feature is coupled with the higher fire safety related with low emissions of smoke and hazardous gasses.
Managing Director, Lapp India