However, any wiring system (cable or bus duct) required to operate in fire must not only account for the electrical integrity of the circuit in order to ensure the reliable function of the life safety and firefighting equipment connected but also for the effects of fire on voltage drop, reduced conductor conductivity due to increased conductor resistance at fire temperatures and the additional ohmic heating generated by carrying the required load under these conditions. Burning Polyethylene (which can be seen from the table above has the highest MJ fuel load per Kg of all insulations) will generate almost 3 times more heat than an equivalent PVC cable. The following table compares the fire load in MJ/Kg for common cable insulating materials against some common fuels. To provide cables which are halogen free, cable makers most often choose polymers like polyethylene (PE & XLPE) because it is easy to process and cheap however, although polyethylene is halogen free it has a naturally high fire load.

In particular, fires in confined areas like buildings, tunnels and underground environments cause oxygen levels to drop near the fire source and this can contribute to incomplete burning and smoldering which may produce increased amounts of smoke and toxic by-products including CO (Carbon Monoxide). In Australia, unlike any other country, AS/NZS3008.1.1:2017 has tables allowing some cable designs to operate at conductor temperatures to 110°C. Whilst technically possible for the cables, what has not been fully considered by Australian standards is the intrinsic change this cable operating temperature may have on the cable’s flammability. Unlike other cables, fire resistant cables have to work even when directly exposed to the fire to keep essential equipment working: Fire alarms, Emergency Lighting, Emergency Voice Communication, Fire Sprinkler pumps, Fireman’s Lift sub-main, Smoke extraction fans, Smoke dampers and shutters, Stair pressurization fans, Emergency Generator circuits etc.. If the essential cable system fails during an emergency then the connected emergency equipment fails and is likely with devastating consequences. You will need to plug in the power cord of the extension cable in any socket in your home and then you can just use the long cable to the extent that and place it near you.

In these cases, cable manufacturers need to use other non-halogenated materials, mostly with flame retarding fillers like alumina-trihydrate (ATH). Selecting a vacuum cleaner seems like a fairly easy process, however the fact is that you have a lot that has to take into consideration. Europe, UK, Australia and many countries around the world have a different approach: Halogen Free and Flame Retardant. It is common for specifications to call for halogen free cables and because of this, encourage the use of Polyethylene because it is halogen free. Along with this, the pedestal fan has an added protection where the guard is being powder coated with a polymer ring as well. Whilst we may understand this, we seldom think much about cables because the electric wiring systems we use are mostly hidden and embedded in the construction, ceiling spaces, riser shafts or wall cavities. The first and most important aspect of smoke is how much smoke? When considering fire safety we must first understand the most important factors.

Simply specifying low smoke cables to common British or IEC standards then thinking this will provide a low smoke environment during a real fire may unfortunately, in practice, be of little help for the people actually involved. It also can improve electric cable's performance of antiseptic, acid-resisting, high temperature resisting, etc. And improve the stability in a harsh environment. Rise in about 188 minutes.The good news is that these heaters can be left safely unattended overnight, providing a warm work environment the following day and bringing surfaces (such as drywall mud) up to the perfect working temperature for sanding or painting. Halogen-Free Flame Retardant cables often use a more pure polymer like Polyethylene (PE or XLPE) or EPR for the insulation which has good electric and mechanical properties but may not be very flame retardant. Halogens like Chlorine are particularly good additives that help retard flame propagation and don’t significantly impact the dielectric properties of the polymer, so Halogens are used in both cable insulations and in cable sheaths. The higher the heat of combustion (MJ/Kg) the more oxygen is needed, so by choosing insulations (even if Halogen Free) with high fuel elements is adding significantly to at least four of the primary dangers of fire: Temperature rise, Oxygen depletion, Toxic gas emission, and Flame spread.

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