Fire property

CeUular polymers are also used for pipe and vessel insulation. Spray and pour-in-place techniques of appHcation are particularly suitable, and polyurethane and epoxy foams are widely used. Ease of appHcation, fire properties, and low thermal conductivity have been responsible for the acceptance of ceUular mbber and ceUular poly(vinyl chloride) as insulation for smaller pipes. 

Fire properties of insulation materials range from the highest to the lowest, from non-combustible to flammable with toxic fume emission. Generally, inorganic materials tend to be non-combustible while organic (or oil-based) materials are combustible, but many have surface treatments to improve their fire-safety rating. 

Glass-reinforced aluminum foil with either a bright polished or white lacquer surface is utilized with most types of insulant. Primarily it is used as a vapor control layer or as a means of upgrading the fire properties of plastic foams, but it does give a semi-decorative finish to the insulation. It is therefore often use where the insulation is open to view but located away from direct risk of mechanical damage. 

Table 5, Effect of calcination temperature of Cera hydrate on the fired properties of p" -alumina...

Altered density of voltage-dependent ion currents in neurons Such changes may considerably affect the firing properties of neurons. They may also affect how neurons integrate a given synaptic input. 

Table III. Effect of Inorganic Additives on the Fire Properties of Brominated Polyester Resin...

A discussion of test methodology is beyond the scope of the present paper. However, the fact that established tests do not accurately reflect the behavior of materials in fires has been widely recognized (9), and the search for more meaningful techniques for the evaluation of engineering materials has continued to be a valid research objective. The development of the cone calorimeter, a bench-scale tool for the evaluation of fire properties of materials (10a) at NBS, is of particular significance in this context. 

A large number of procedures are now available for measuring fire properties, but many of them are of little interest since they represent outdated technologies. Thus, in order to obtain a realistic estimate of fire hazard for a scenario it is essential to measure relevant fire properties. Furthermore, the appropriate instruments have to be used, viz. those yielding results known to correlate with full scale fire test results. 

True fire hazard can be determined only in a specific scenario. Therefore, it is necessary to determine which fire properties are most relevant to the scenario in question. These fire properties will then have to be measured and combined in order to obtain an overall index of fire hazard. As a general rule, it is clear that the most important individual property that governs levels of fire hazard is the rate of heat release the peak rate of heat release is proportional to the maximum intensity a fire will reach. 

The fire properties most relevant to each stage of a fire are ... 

Some of the fire properties mentioned have been measured and well understood for a long time, but others are relatively new concepts. The most important fire properties and proposed measurement methods will thus be discussed in the following sections. 

Rate of Heat Release and Associated Fire Properties... 

Other Fire Properties Useful for Aspects of Fire Hazard... 

This secondary effect of materials is illustrated by the difficulties encountered, in a recent study [54], when attempts were made to correlate CO concentrations measured in small scale and full scale fire tests. The same small scale equipment (typically the cone calorimeter rate of heat release test) could predict adequately a number of very important full scale fire properties, including ignitability, rate of heat release, amount of heat release and smoke obscuration. It could not, however, be used to... 

It is possible, however, to estimate effects on fire hazard in a particular scenario by simpler means. In some cases, an adequate choice of fire properties can be made. Then, the combination of test results into a matrix form, or into a single parameter, can indicate, even if only semi-quantitatively, the effect of varying a particular material or fire protection measure on fire hazard. 

Fire safety in a particular scenario is improved by decreasing the corresponding level of fire risk or of fire hazard. Technical studies will, more commonly, address fire hazard assessment. Fire hazard is the result of a combination of several fire properties, including ignitability, flammability, flame spread, amount of heat released, rate of heat release, smoke obscuration and smoke toxicity. 

The most important fire property associated with fire hazard is the rate of heat release the peak rate of heat release is an indication of the maximum intensity of a fire. 

In order to improve fire safety for each scenario, the most relevant fire properties for that scenario have to be measured, with the appropriate instruments. 

What is proposed is that material fire properties are determined by a carefully chosen set of national tests, appropriate to the material usage, which will cover the main field of interests of most regulators directly. Those which cannot be satisfied directly have to be satisfied by a translation or "transposition document" derived from the Blachere Report. 

The traditional way of measuring fire properties is to determine each property individually by carrying out small scale tests on materials, in isolation of the fire scenario of interest. A crude means of fire hazard assessment would then be to establish minimal "passing" standards for each test and require all materials to meet them. 

However, the majority of small scale tests actually used to measure fire properties are incapable of determining either more than a single property or combined properties. Furthermore, there is, often, no attempt to investigate whether the test results are can be related to results to be expected in full scale fires. This is incompatible, thus, with modern concepts of fire hazard. 

Tewarson, A., and Newman, J.S., "Scale Effects on Fire Properties of Materials," Fire Safety Science, Proceedings of the First International Symposium, 1986, Hemisphere Publishing Corp., Washington, DC, p. 451. 

Address the issue of PVC fire properties, including smoke toxicity and hydrogen chloride decay. 

Other papers in this volume address the importance of a variety of fire properties on fire hazard, in particular the relative importance (or lack of it) of toxic potency of smoke (e.g. Ref. [1]). 

The fire properties of PVC have been put into perspective recently [4, 5]. They show that PVC is a polymer with a high ignition temperature and low flammability. Furthermore, PVC products are associated with a low rate of heat release as well as little total heat released [4-9]. This will depend, clearly, on the type of product, since plasticised PVC products are obviously more flammable than rigid ones. 

Hirschler, M.M. and Smith, G.F. Determination of Fire Properties of Products bv Rate of Heat Release... 

Hopkins, D. and Quintiere, J.G., Material fire properties and predictions for thermoplastics, Fire Safety J., 1996, 26 241-268. 

These fibres are used for their thermal and fire properties combined with mechanical performances similar to those of glass fibres. Unfortunately, their price is three times higher than that of glass fibres and applications are reduced. 

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