Experimental evaluation of fire toxicity test methods

An experimental evaluation of the most common bench-scale tests methods for fire toxicity was conducted by RISE Fire Research. The background of the work was the on-going discussion in the fire community on the applicability and relevance of these test methods. The test methods included in the programme were the ISO/TS 19700 steady-state tube furnace (SSTF), the controlled atmosphere cone calorimeter (CACC), and the EN 45545-2 smoke chamber test (SC). In these tests the production of selected toxic gases was quantitatively analysed using FTIR. Tests for the measurement of toxic gas production were made with eleven different materials used as test specimens, both combustible and non-combustible materials. The materials were commercially available insulation products provided by EURIMA, the sponsor of the project. These materials should not be regarded as typical or fully representative of a product category. The evaluation of the results from the different test methods was divided into combustible test specimens and non-combustible test specimens. That was because the test conditions in the first case are greatly influenced by the combustion behaviour of the test specimen, while in the second case the test conditions are more constant. A general observation was that there in many cases was correlation between both species composition and level of toxic gas species yields between test methods when the combustion conditions were similar. In cases where yields differed significantly it could in most cases be explained by clear differences in test conditions. For combustible materials it was concluded that the SSTF offers the best means for conducting tests at pre-decided and controlled flaming combustion conditions. The CACC does not give steady-state flaming combustion and the influence of vitiation was limited in the tests made. The SC generally accumulates a mixture of gases from both flaming and non-flaming combustion periods in a test, and the yields measured do not in those cases represent any specific combustion stage. For non-combustible materials a general observation was that any of the test methods investigated in principle could be used since the influence on the test conditions from the material itself is limited compared to combustible materials. However, there were specific properties and limitations of the different test methods observed that are important to consider