A heated debate

Since the Kings Cross disaster, fire safety issues regarding reinforced plastics have been heating up, and there’s been a lot of pressure to minimise risk posed by materials used within enclosed spaces. Martin Jones, technical services manager at Attwater Group, spoke to DE about the trend towards inherently non-flammable materials.

`Reinforced plastics have been specified for electrical insulation purposes for years. Many equipment designs date from the 1940s, 50s and 60s and it’s surprising how many of these are still around. In the past decade however, the flammability of materials, particularly those used in an enclosed environment, has become a primary concern.

`Most reinforced plastics can be designed to have some fire resistance, and additives are available which inhibit burning. Unfortunately, many of these compounds give off toxic fumes and in a fire, whilst the inhibited material is unlikely to be the cause, it can become a major contributing factor to the conflagration.

`Another problem is the number of different ‘flammability’ tests. The majority of these are difficult to relate to one another and don’t always give a true indication of what will happen in a real fire.

`In an ideal world, specifiers would need to consider the overall heat in a fire situation, in addition to the ventilation and the smoke escape, as all these can have a massive impact on the results of a flammability test. But in reality, no one can truly predict what will happen.

`Many additives have been developed specifically to inhibit burning and many of these are very effective indeed in preventing ignition. Often this is sufficient for an insulating material, which may be housed within a sealed unit or present in such relatively small quantity compared to the surroundings as to present an insignificant risk. However in an enclosed area or where larger quantities of material are involved, this may not be the case.

`However, there are composite materials around which are inherently flame retardant and give off relatively little in terms of toxic by products when exposed to fire.

`The best of these is silicone glass, which is being used extensively as an insulating material in underground situations. Silicone is inherently flame retardant and in combination with glass exhibits excellent properties. Phenolic glass laminates also exhibit extremely good properties. Both of these materials are beginning to find ever more widespread use in critical locations.

`Of course, there is always a drawback, and the materials are more expensive than polyesters or commercial SRBP laminates.’