The authors noted that the yields of the toxicantsproduced an atmosphere in the tests which fell well below their Immediately Dangerous to Life and Health (IDLH) values. The results indicated that the formation of the precursor, TDI, was much faster and preferable to depolymerisation when the volatile compounds could escape. 2005; Blomqvist & Lonnermark 2001). (2015) questioned their methodology and noted that the authors did not address the release of HCl and its contribution to the acute fire toxicity of the fire retarded foam. The authors did not specify which analytical methods were used in the quantification of the fire gases, only that they were sampled via a sampling bag. Similarly, Busker et al. However, while the char produced when the polymer was heated at 370C contained only 20% of the total nitrogen from the polymer, 40% of that (8% of the total nitrogen in the polymer) was recovered as HCN when the char was burned at 600C. The presence of Cu2O drastically decreased the yield of HCN in polyurethane foams at lower temperatures, but had little effect at high temperatures. This suggests that any amines formed would have reacted with isocyanates in the vapour phase to form ureas, some of which would have condensed to produce the observed waxy white substance. PDF CORE - Aggregating the world's open access research papers True. Additionally, the authors suggested the positions on the polyol chain where bond scission could occur, explaining the presence of the short-chain alkenes, aldehydes and ketones (Scheme9). Around 1015% of the nitrogen in the polymer can be converted into HCN with some being released in isocyanates, aminoisocyanates and amines in the fire effluent. 5-step decomposition mechanism for flexible polyurethane foam (Rogaume et al. Material composition, temperature and oxygen concentration are normally the most important. \( \phi =\frac{actual\; fuel\;to\; air\; ratio}{stoichiometric\; fuel\;to\; air\; ratio} \). Fire and Materials 9:p125134, Levin BC, Paabo M, Bailey CS, Harris SE (1986) Toxicity of the combustion products from a flexible polyurethane foam and a polyester fabric evaluated separately and together by the NBS Toxicity Test Method. . The authors declare that they have no competing interests. Elemental analysis of the polymer and the char showed that 80% of the nitrogen in the polymer was lost when heated at 370C, but only 0.6% was recovered as HCN when burned at 600C. At 850C the yield of HCN was higher with 16mgg1 at ~2.0. . The reported yields for the tests performed can be found in Table8. 1982), and a three . However, unlike a real fire, the heat flux remains constant, and so when the oxygen concentration falls, the flame may be extinguished. Acrolein and formaldehyde are formed especially from cellulosic materials under non-flaming decomposition conditions, but products of vitiated combustion contain other organic irritants. Alongside this, the decomposition of the foam into an amine, alkene and carbon dioxide was also proposed. Does the foam give off toxic fumes if burned? Oxygen depletion can be lethal if the oxygen concentration falls below tenable levels (~6%). The applied heat flux must be large enough for burning to continue at oxygen concentrations as low as 5%.
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polyurethane foam, when burned gives off