Fire test methods smoke toxicity

Static smoke chamber methods have major limitations in terms of being indicative of the fire hazard due to smoke toxicity of products and materials in actual fires. As combustion products accumulate in the chamber during a test, the burning behavior of the test specimen may have a significant effect on the level of vitiation (oxygen concentration) and temperature rise in the chamber. 

ASTM E 1678 Standard Test Method for Measuring Smoke Toxicity for Use in Fire Hazard Analysis. ASTM International, West Conshohocken, PA. 

The range of toxicity test methods is bound to produce different fire conditions, and hence different toxic product yields. Four test methods (NBS Smoke Chamber, NF X 70-100, Fire Propagation Apparatus [FPA], and SSTF) have been compared, primarily from published data64 66 using the carbon monoxide yields and hydrocarbon yields (not recorded in the NFX tests), which are both fairly good indicators of fire condition, for four materials (LDPE, PS, PVC, and Nylon 6.6), at two fire conditions, well-ventilated and under-ventilated. The CO and hydrocarbon yields are shown in Figures 17.9 and 17.10. 

In the 1980s, New York incorporated into its code (New York State Uniform Fire Prevention and Building Code), in Article 15, Part 1120, a requirement for Combustion Toxicity Testing, 23 based on a smoke toxicity test developed at the University of Pittsburgh.24 The test method was never standardized by either ASTM or NFPA because of the several concerns about its scientific validity.25 28 The New York State regulation did not include pass/fail criteria and has since been rescinded. 

Hirschler, M.M. and Grand, A.F., Comparison of the smoke toxicity of four vinyl wire and cable compounds using different test methods Fire Mater., 1993, 17, 79-90. 

National Materials Advisory Board Fire Safety Aspects of Polymeric Materials, Technomic Publishing Co., Inc., Westport Vol. 1 Materials State of the Art, 1977 Vol. 2 Test Methods, Specifications, and Standards, 1979 Vol. 3 Smoke and Toxicity (Combustion Toxicology of Polymers), 1978 Vol. 4 Fire Dynamics and Scenarios, 1978... 

The use of FTIR (Fourier transform infrared) spectrometers as a continuous monitoring technique overcomes many of the problems associated in analyses of hot fire gases. FTIR offers an opportunity to set up a calibration and prediction method for each gas showing a characteristic spectral band in the infrared region of the spectrum. A European project, SAFTR, aims to further develop the FTIR gas analysis of smoke gases to be an applicable and reliable method for the determination of toxic components in combustion gases related to fire test... 

Basic Mechanisms. Finally, further work is necessary on fundamental mechanisms of individual fire retardants. These mechanisms are a function of the particular chemicals involved and the environmental conditions of the fire exposure. There is a need to establish common methods and conditions for determining these mechanisms in order to compare different treatments. This would give us a better understanding of how these compounds work in action and would provide a more efficient approach for formulating fire-retardant systems than a trial and error approach. Correlations also need to be established between rapid precise thermal analysis methods and standard combustion tests. Retardant formulations could be evaluated initially on smaller (research and development size) samples. The more promising treatments could be tested for flame-spread index, heat release rate, and toxic smoke production. 

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