polyurethane foam, when burned gives off

I recently purchased a memory foam (polyurethane) mattress and was looking online to see how long they take to "air out". Studies have found that infant mattressesespecially those made with polyurethane foam, which contains the hydrocarbon tolueneare a major off-gassing culprit (Boor, et. Primarily, isocyanates react with alcohols to produce urethane linkages in the polymer (Scheme1). ISO 13571 (2007) considers the four major hazards from fire which may prevent escape (toxic gases, irritant gases, heat and smoke obscuration). Refer to MSDS. CEN/TS 455452 (2009) Railway applications - Fire protection on railway vehicles Part 2: Requirements for fire behaviour of materials and components, Chambers J, Jiricny J, Reese CB (1981) The Thermal Decomposition of Polyurethanes and Polyisocyanurates. The study also suggested that any remaining isocyanates residue would react with themselves to produce polycarbodiimides, thus anchoring the isocyanate precursors in the condensed phase until around 600C, where they would fragment. Off-gassing is the unpleasant odor caused by volatile . Most polyurethanes are cross-linked to some degree and decompose without melting. The open cone calorimeter replicates the early well-ventilated stage of flaming where a fire would be too small to produce enough toxicants to cause harm except in very small enclosures. April 30, 2021 April 16, 2021 by Shobita Ravichandran. 12, feeds the sample (typically around 25g of pellets or granules) into its hot zone at a fixed rate, under a controlled air supply, inside a horizontal silica tube of diameter 48mm, allowing adequate mixing of fuel and oxidant. However, due to the poor reproducibility of smoke chamber experiments, the tendency for it to give very low HCN yields, and the fact that the experiment is well-ventilated, the reported toxicity is likely much lower than in a real fire situation. The difference in the decomposition of rigid and flexible polyurethane foams was investigated by Chun et al. 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 second results in a brief stimulation, followed by severe depression, of respiratory frequency, also starving the body of oxygen, and causing convulsions, respiratory arrest and death (Alarie 2002). 5-step decomposition mechanism for flexible polyurethane foam (Rogaume et al. Insulation, like all building products, has an 'embodied' carbon footprint resulting from energy use during the manufacturing process. The interior of large flames are always under-ventilated, because oxygen cannot penetrate the flame. New memory foam smell? The samples were heated at 800C in a static tube furnace, with the effluent being cooled to <50C before entering an exposure unit. The full-scale test showed good accordance with the SSTF data considering the inherent unreliability of large-scale testing. Again, above 600C the compound and any yellow smoke present was decomposed into smaller volatile fragments. When a liquid fuel gives off enough vapors so that it can be ignited and burn, has reached its? MathSciNet Since 2004, by law, the U.S. requires all mattresses to be fireproof to a specific temperature point and ever since the toxicity levels in foam memory mattresses have increased. This is due to the large range of available fire retardants found in polyurethane foams, which suggests that the toxicity will likely follow the general trends in the literature for all materials regarding fire retardants. 13) (UK Fire Statistics 2013). Fumes Tiny particles are produced from heating, volatilization, and condensation of metals (examples: zinc oxide fumes from welding of galvanized metal). DiNenno et al. The yield was much lower at 800C with 7.4mgg1 but at 1000C and 1200C the yield increased significantly to 33.9mgg1 and 48.1mgg1 respectively. The toxic product yields may be quantified from the gas concentrations and mass feed rate during the steady state burn period. The yields of some of the most toxic gases from unwanted fires (such as CO, HCN and some organic irritants) have been demonstrated to be directly related to the combustion conditions (Purser 2002). Substituted ureas decompose between 235 and 250C and carbodiimides decompose between 250 and 280C. However there was significant scattering of the results with both high and low outliers (26mgg1 at 1.22 and 9mgg1 at 1.95). Two mechanisms have been identified for the toxic effects of cyanide. 9). A "combustion modified high resilience" flexible polyurethane foam (CMHR-PUF) and a polyisocyanurate (PIR) foam were analysed a steady state tube furnace apparatus. Fire Safety Science - Proceedings of the First International Symposium, p1111-1122, Markets and Markets report (2011) Methylene Diphenyl Diisocyanate (MDI), Toluene Diisocyanate (TDI) and Polyurethane Market (2011 2016): Markets and Markets CH 1596, July 2011, Marsh ND, Gann RG (2013) Smoke Component Yields from Bench-Scale Fire Tests: 4. 2 (Avar et al. The fire toxicity of polyurethane foams. However, from a fire toxicity perspective it is generally assumed that heat and other gases will have already prevented survival, while other toxicants such as CO or HCN, will be present in lethal quantities further from the fire where the oxygen depletion would not be considered harmful. Journal of Analytical and Applied pyrolysis 108:p143150, Hartzell G (1993) Overview of Combustion Toxicology. The widespread use of flexible polyurethane foams in furniture and other upholstery, where they are usually covered in some kind of fabric has prompted some authors to investigate the effects of covering the foam on the yield of toxic products. 1982), the authors exposed male Fisher 344 rats in a 200L exposure chamber to the fire effluent from the flaming and non-flaming combustion of both materials. polyurethane foam production and up to a point the amount of water added will be inversely proportional to the density of the foam. These fumes could lead to irritation of the eyes, throat, and lungs, and could cause more severe allergic reactions for individuals with chemical sensitivities. The samples tested included both commercial rigid polyurethane foam and polyisocyanurate foam. At ~2.0 the CMHR-FPUR resulted in 8% and 11% nitrogen recovered as HCN for 650C and 850C respectively. Woolley et al. Bott et al. The polyester based foam produced nearly double the amount of HCN between 900 and 1000C than the polyether foam with an increase from 20.8mgg1 to 38.0mgg1. However, during the combustion of polyurethane foams, the HCN yield is notably higher when the fire progresses from smouldering to flaming combustion. However, this did not take into consideration the incapacitating effects of the release of irritant gases. National Fire Protection Association, Quincy MA, USA, pp 296, Purser DA, Purser JA (2008a) HCN yields and fate of fuel nitrogen for materials under different combustion conditions in the ISO 19700 tube furnace. CO yields are generally very low for well-ventilated conditions (in the absence of halogens) but increase considerably under-ventilated combustion conditions. Conversely, nitric oxide gas at low concentrations(~20 ppm) has been used to aid breathing in the treatment of respiratory disorders (Kavanagh & Pearl 1995). The formation of HCN was at a higher temperature in both air and nitrogen (400C and 550C respectively) with an average concentration of 200ppm at 500C. They also asserted that the toxicity of the fire retarded foam was less than or equal to wood on a mass/mass basis and that wood contributes significantly more to residential fires in terms of fire smoke toxicity. Manage cookies/Do not sell my data we use in the preference centre. In particular, reports that used non-standard tube furnace apparatus lacked sufficient information about the conditions of the experiment and as such were not included. The protocol has been modified as a toxicity test by the mass transport industries, in the aircraft (EN 2826 2011), maritime (Fire Test Procedure Code 2010), and railway tests (CEN/TS 455452 2009). 2023 BioMed Central Ltd unless otherwise stated. These reactions make up the basis of polyurethane chemistry and can be used to tailor polyurethanes with a range of properties by varying the structure and ratios of the individual components. Appropriate formulation affords a degree of control over the cross-linking in the polymer without the need for additional cross-linking agents. Reliable rate of heat release, fire effluent toxicity and smoke generation data are all essential components of such an assessment. The difference with other polyurethane foams is that memory foam also contains added chemicals that increase its viscosity and elasticity, hence its alternate name, viscoelastic foam. Busker RW, Hammer AH, Kuijpers WC, Poot CAJ, Bergers WWA, Bruijnzeel, PLB (1999) Toxicity testing of combustion products of polyurethane and polyvinylchloride. The sample is spread evenly in a silica boat over a length of 800mm and fed into a tube furnace at a typical rate of 1gmin-1 with flowing airat a rate of 2-10 L min-1. Asphyxiant or narcotic gases cause a decrease in oxygen supplied to body tissue, resulting in central nervous system depression, with loss of consciousness and ultimately death. This char can decompose further, leaving behind a residue at >800C, to produce simple organic fragments and some polycyclic aromatic hydrocarbons (PAHs). Aromatic diisocyanates ortho- or para- to one another will have an activating effect on each other, thus increasing their reactivity. At sufficiently high concentrations, or when attached to submicron particles, such as soot, most irritants can penetrate deeper into the lungs, causing pulmonary irritation effects which may cause post-exposure respiratory distress and death, generally occurring from a few hours to several days after exposure, due to pulmonary oedema (flooding of the lungs) (ISO 13571 2007). Acrolein and formaldehyde are formed especially from cellulosic materials under non-flaming decomposition conditions, but products of vitiated combustion contain other organic irritants. EN 2826. DiNenno) Fourth Edition. National Bureau of Standards, Gaithersburg MD, Barbrauskas V, Singla V, Lucas D, Rich D (2015) Letter to the Editor- Questions about the conclusions in Blais and Carpenter 2013. https://doi.org/10.1186/s40038-016-0012-3, DOI: https://doi.org/10.1186/s40038-016-0012-3. In contrast to the relativelywell-defined effects of asphyxiants, the effects of exposure to irritants are more complex. City, Salt Lake, UK Fire Statistics 2013 (and preceding years) United Kingdom, Fire Test Procedure Code (2010) Maritime Safety Committee, (MSC 87/26/Add.3) Annex 34, Part 2 Smoke and Toxicity Test. (1972) noted that the yellow smoke was produced up to around 600C, where it would then decompose to give a family of low molecular weight, nitrogen containing products including hydrogen cyanide, acetonitrile, acrylonitrile, pyridine, and benzonitrile. Fire and Materials 6:p1315, Neviaser JL, Gann RG (2004) Evaluation of Toxic Potency values for Smoke from Products and Materials. Free of VOCs and HAPs. Similarly, the polyether based foam produced 15.1mgg1 to 28.1mgg1. Additionally, the amount of CO generated for both materials began to taper off at 1.2-2.0 as the available oxygen becomes so low that the generation of CO becomes limited, while the yield of HCN continues to increase with equivalence ratio and temperature. National Fire Protection Association, 82, p 161, Vilar WD (2002) Chemistry and Technology of Polyurethanes - Chapter 1. Fire and Materials 5(4):p133141, Christy M, Petrella R, Penkala J (1995) Controlled-atmosphere cone calorimeter. However, the lower yields can be attributed to the fact that the cone calorimeter is a well-ventilated scenario, estimated as ~0.7 (Schartel & Hull 2007). Carbodiimides are produced by the reaction of isocyanates in the presence of a catalyst (such as phospholine oxides) (Scheme8) (Avar et al. Thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) showed that the polyether based polyurethane began to decompose at 258C, with a second decomposition stage at 350C (which could be attributed to the fragmentation of the polyether polyol). Overall, the results suggested that the polyether based polyurethane was less thermally stable in the presence of oxygen than the polyester, and both were generally less stable in air than in a nitrogen atmosphere. This results from PVC having 56.8% chlorine in its base polymer weight and it is well known that chlorine is one of the few elements that confers good fire properties to a polymer1,2. The authors presented a large set of data for all of the test methods, including a range of test conditions, air flow rates, oxygen concentration, and mass loadings. TRH wrote the fire toxicity section of the manuscript. In order to reduce the ignitability, and to a less extent the surface spread of flame and peak heat release rate, fire retardants are commonly added to commercial polyurethane foams in order to meet specific regulatory demands. A summary of these structures is shown in Fig. The calculations showed that, for both the rigid polyurethane and the polyisocyanurate, hydrogen cyanide is the major toxicant in smouldering, well-ventilated and under-ventilated flaming. The sample is a 7575mm square solid sheet and the standard for smoke measurement states that the results are only valid at the thickness tested (typically 14mm). The data was presented as material-LC50 values for 30min exposures with 14-day post-exposure of test animals and can be found in Tables10, 11 and 12. However, as noted by Paabo and Levin (1987), many studies into the decomposition of polyurethane foams do not differentiate between flaming and non-flaming decomposition, and focus on the temperature of decomposition rather than the presence of flames. Progressive changes in the composition of a static specimen (for example due to char formation) provide additional complexity. Toxic product yield data from the smoke density chamber (ISO 56592 2012), the controlled atmosphere cone calorimeter (based on ISO 56601 2002), the fire propagation apparatus (FPA) (ASTM E 2058), the French railway test (NFX) (NF X 70100 2006), and the steady state tube furnace (SSTF) (ISO/TS 19700 2013) were compared to published large-scale enclosure fire data (from a standard ISO 9705 room) for two polymers, polypropylene (PP) and polyamide 6.6 (PA 6.6). The authors noted that the polyester polyols were more stable than the polyether polyols, with the latter fragmenting at a lower temperature (300400C). Research predicting the carbon monoxide evolution from flames of simple hydrocarbons, reviewed by Pitts (1995), has shown the importance of the equivalence ratio . The cribs used in the ISO 9705 tests were constructed from PIR sticks which burned rapidly, albeit with minimal damage to the room. For both materials there is a clear increasein yield from the well-ventilated to under-ventilated conditions. Avar G, Meier WU, Casselmann H, Achten D (2012) Polymer Science: A Comprehensive Reference, Polymer Science: A Comprehensive Reference, 10, p411-441.

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