Fire behaviour

The major improvement sought in polymers in terms of their fire behaviour is reduction of flammability. For certain applications, however, reduction in smoke evolution is sought but these two aims tend to be mutually incompatible. Reduction in flammability is brought about by making the combustion process less efficient. A penalty for inefficient combustion is increased smoke production. Similarly a reduction in smoke evolution may be achieved by increasing the efficiency of any accidental combustion that is, by increasing the flammability. 

Babrauskas, V., Bench-Scale Methods for Prediction of Full-Scale Fire Behaviour of Furnishings and Wall Linings. SFPE Technology Report 84-10, Soc. Fire Prot. Engineers, Boston, MA, 1984. 

However, the differences between the national test methods are considered to be the major barrier to trade. Whilst the harmonization of test and classification systems is insufficient on its own to provide for a free market, it is undoubtedly a necessary condition to it. Without a common method of evaluating the fire behaviour, there is no basis for a common regulatory specification. 

To develop standards utilizing relevant existing work, where available e.g. in ISO, CEC and EFTA, for assessing the fire behaviour of building products, components and elements of construction. 

It is nearly 20 years ago that the unacceptable fire behaviour of "modern" upholstered furniture became highlighted in the UK by Fire Brigade reports of domestic fires. This poor performance was blamed on the use of flexible polyurethane (PU) foam upholstery and demands were made to ban PU foam or at least to insist on the use of flame retarded PU foam. 

The response to this situation in the early 1970 s was to set-up three major research programmes to investigate the fire performance of furniture and furnishings. These programmes, (2), (3), (4), not surprisingly, produced similar conclusions that the adverse fire behaviour of upholstered furniture and made-up beds... 

In 1978, the Home Office report (14) concerning the fire behaviour of new (i.e. post 1945) materials specifically criticised the fire performance of upholstered domestic furniture and recommended manufacturers to improve ignition resistance, to reduce flammability, and to reduce the rates of smoke and toxic gas generation. 

Fire behaviour of products constitutes a major and permanent preoccupation in multiple areas building and construction, transport, electric and electronic engineering, furniture, etc. This theme possibly involves the largest number of standards, regulations or legislations at national level as well at international level. It is in this context that the use of flame retardants for plastics must be envisaged. Several themes are outlined. 

Infusibility thermosets are degraded by heat without passing through the liquid state. This improves some aspects of fire behaviour except for particular cases, they do not drip during a fire and a certain residual physical cohesion provides a barrier effect. 

Better fire behaviour, lower smoke emission and more widespread use of halogen-free grades. 

Fire behaviour depends, initially, on the nature of the polymer. However, the use of fireproofing agents, special plasticizers and specific fillers can modify this behaviour very significantly. 

Specific properties specific grades and specific additives Fire behaviour... 

Fire behaviour is very complex for several reasons ... 

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