Fire performance ignitability

Test results show that thin coatings (2-5 mils) can significantly effect the fire performance of plastic substrates. Most EMI coatings decrease ignitability test results. Coatings tend to level diverse flame spread and ease of extinction performance. A 2-mil coating can reduce the 1, value in ASTM E162 Radiant... 

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. 

Combining ignition resistant fabrics with combustion modified PU foam will significantly improve the fire performance of upholstered furniture and mattresses. 

Note FPI, fire performance index (m2 s/kW) RHR, rate of heat release (kW/m2) SEA, smoke extinction area (m2/kg) SP, smoke parameter (MW/kg) TTI, time to ignition (s). 

A typical criticism of this test method, for example, is that ordinary newsprint, and even tissue paper, will meet its requirements. That is a valid criticism. However, there seems to be general agreement that, in spite of its lack of sophistication, this test method has been successful in eliminating the fabrics with the poorest fire performance from the general population of fabrics in use for apparel in the United States. Thus, fabric types such as the fibrous torch sweaters with raised surface fibers that ignite readily and spread flame quickly are no longer legally sold in the United States due to the test requirements. The test has also been able to screen out the use of very sheer... 

In the early 1980s, Vytenis Babrauskas, at the NIST (then NBS), developed a more advanced test method to measure RHR the cone calorimeter (ASTM E 1354).71164 This fire test instrument can also be used to assess other fire properties, the most important of which are the ignitability (as discussed earlier), mass loss, and smoke released. Moreover, results from this instrument correlate with those from full-scale fires.165-170 To obtain the best overall understanding of the fire performance of the materials, it is important to test the materials under a variety of conditions. Therefore, tests are often conducted at a variety of incident heat fluxes. The peak rates of heat release (and total heat released) of the same materials shown in Table 21.15 at each incident flux, are shown in Table 21.16.147... 

Propensity of flashover The ratio of ignition time to peak rate of heat release. It is the same as fire performance index iirs/kW... 

Table 3.12 Fire performance of phenolic/glass fiber RP compounds (ignitability/heat)...

Unsaturated polyesters Aluminium trihydrate Cone calorimetry to measure ignition time, heat release, smoke emission and toxicity, even small additions of aluminium trihydrate improved fire performance [42, 43]... 

In both the test standards, fire propagation and smoke release propensity of polymers are quantified. Three types of tests are performed ignition, combustion, and fire propagation. In the ignition and combustion tests, horizontal samples as squares [100 mm (4 inch)] or circles [100 mm (4 inches) diameter], 3 mm (0.1 inch) to 25 mm (1 inch) in thickness are used. For fire propagation tests,... 

Flame retardants may be incorporated as additives in particulate or coating form. They may be halogenated or non-halogenated. Their use must be considered in conjunction with their effect on mechanical properties, especially for durability. There is a need to match all the flammability characteristics, ignitability, heat development, smoke and toxicity and to ensure continued structural integrity. Some fire retardants may improve one of these fire performance characteristics at the expense of others. 

Formulations containing ammonium octamolybdate (AOM) also showed good fire performance, particularly with respect to reductions in heat release rates and smoke emissions, although the increase in time to ignition was significantly lower than that for ZHS. However, AOM caused a reduction in the time to decomposition in the thermal stability test of 9 minutes, and a decrease in Charpy impact of 4 kJ/m. It is also more expensive than ZHS. 

Results indicate that while there are significant differences among vehicles, the large majority of car interior materials tested (a random yet indicative cross-section) represent a fire performance that is, at best, mediocre. Moreover, the comparison between the two sets of materials shows that car interior plastics are likely to ignite much faster than commercially available plastics and release heat almost twice as fast. 

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