polyurethane foam toxicity

The effect of asphyxiants and deep lung irritants depend on the accumulated doses, i.e. The samples tested included both commercial rigid polyurethane foam and polyisocyanurate foam. During these tests, the PIR was set up as wall panels covered on two faces with aluminium foil. Babrauskas et al. The findings from these studies demonstrated that yields of different toxic products are highly dependent on equivalence ratio (either positively or negatively correlated), and elemental and molecular composition of the material. NBSIR 82–2532. Energy and Buildings 43:p498–506, Stec AA, Hull TR (2014) Fire Toxicity Assessment: Comparison of Asphyxiant Yields from Laboratory and Large Scale Flaming Fires. Both of the materials showed a clear relationship with the HCN yield increasing with ϕ. This can be explained by the fragmentation of nitrogen containing organics in the flame and in the effluent, as suggested by studies of the inert-atmosphere decomposition of polyurethane materials. The cone calorimeter (ISO 5660–1 2002) is probably the most widely used apparatus for measurement of flammability properties such as ignitability and heat release rate (Schartel & Hull 2007). Isocyanates also react with themselves in various ways to produce dimers, trimers and completely new functional groups. Hietaniemi et al. 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. 1985 and Levin et al. 10. The steady state tube furnace produced a CO yield that was closer to what would be expected for under-ventilated conditions. Journal of Analytical and Applied pyrolysis 113:p202–215, Gharehbagh A, Ahmadi Z (2012) Chapter 6: Polyurethane Flexible Foam Fire Behaviour, Polyurethane. Stec and Hull (2011) presented material-LC50 data for rigid polyurethane foam and polyisocyanurate foam, calculated using rat lethality data from ISO 13344 (1996). 2011). Depending on the material, the carbon dioxide in the foam will deteriorate in place or be released out of the material. P.J. The toxic hazards associated with fire and the inability of victims to escape from fire atmospheres may be considered in terms of major hazard factors: heat, smoke and toxic combustion products (Hartzell 1993). The dimerisation of two isocyanates is a reversible reaction that produces uretidione ring (Scheme 6). Similar to the human body, a polyurethane molecule is made up of 4 organic elements: oxygen, carbon, hydrogen and nitrogen. Heat, smoke and irritant gases may impair escape, increasing the risk of a lethal exposure to asphyxiant gases, and can sometimes lung damage causes death in those managing to escape. Fire Safety Journal 43:243–251, Piirilä PL, Meuronen A, Majuri ML, Luukkonen R, Mäntylä T, Wolff HJ (2008) Inflammation and functional outcome in diisocyanate-induced asthma after cessation of exposure. A large number of studies have been performed over the last 50 years to understand the thermal decomposition of polyurethane materials, and as a result of this the mechanism of their decomposition in inert-atmospheres is fairly well understood. The results indicated that the formation of the precursor, TDI, was much faster and preferable to depolymerisation when the volatile compounds could escape. It is produced by linking ethylene molecules to a larger molecule that has a branched chain structure. 8 and Table 3. 1995). 1982), the authors exposed male Fisher 344 rats in a 200 L exposure chamber to the fire effluent from the flaming and non-flaming combustion of both materials. Higher temperatures resulted in the volatilisation of most of the polyurethane precursors via the formation of lower molecular weight compounds. Interflam Conference Proceedings. The overall toxicity of the combined materials was higher, and the average concentrations of the gases throughout the tests were consistently higher than that of the individual materials in both flaming and non-flaming conditions. Similarly to the trend reported by Stec and Hull (2011) in well-ventilated conditions, this can be attributed to gas phase free radical quenching in the material by the chlorine present in both the CMHR-PUF and PIR (2.53 % and 3.56 % chlorine by weight, respectively). Thermoplastics are composed of linear polymer molecules, whose shape can be changed repeatedly on heating and which may be melted and solidified without chemical change. In order to relate the fire effluent toxicity to a "maximum permissible loading", the FED can be related to the mass of material in a unit volume which would cause 50 % lethality for a given fire condition. Irritant gases cause pain and breathing difficulties, leading to incapacitation, such that the victim can no longer effect their own escape (ISO 13571 2012). The controlled atmosphere cone calorimeter. The heating of polyurethanes in an inert-atmosphere results in the progressive rupturing of bonds as a function of temperature. Fire and Polymers II: Materials and Tests for Hazard Prevention 599:p498–517, Chun BH, Li X, Im EJ, Lee KH, Kim SH (2007) Comparison of Pyrolysis Kinetics between Rigid and Flexible Polyurethanes. This agrees with the fact that oxidation of NH3 and HCN to NO (and NO2, although it was not analysed in these experiments) would occur more readily during well-ventilated burning. A review by Paabo and Levin (1987) found that there is no difference in the decomposition products of rigid and flexible polyurethane foams at high temperatures regardless of their differing degradation mechanisms at lower temperatures. Gaithersberg, MD, Babrauskas V, Twilley WH, Janssens M, Yusa S (1992) Cone calorimeter for controlled-atmosphere studies. Polymer International 53:p1585–1610. The rigid polyurethane foam yielded ~55 mg g−1 CO and ~0.5 mg g−1 of HCN. In particular, TDI is a suspected carcinogenic, is classified as very toxic, and is a known respiratory and skin irritant. Several authors have investigated the relationship between bench-scale test data and large-scale test data using polyurethane foams. The authors tested a rigid polyurethane foam using a NBS cup furnace (as described in Levin et al. 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. Fire Research Notes 951:p1–17. Early work by Woolley et al (1975) indicated that the decomposition of polyurethanes up to around 600 °C resulted in the volatilisation of fragmented polyurethane and subsequent release into a nitrogen rich ‘yellow smoke’, containing partially polymerised isocyanates and droplets of isocyanate from the foam. The samples were heated at 800 °C in a static tube furnace, with the effluent being cooled to <50 °C before entering an exposure unit. Synthetic polymeric materials may be divided into thermoplastics and thermosets. Combustion toxicity results obtained using different test methods but measuring the same toxicologic endpoints were compared. (1969) reported the decomposition of rigid polyurethane foams in both nitrogen and air to assess the production of CO, HCN and NH3. The difference in the decomposition of rigid and flexible polyurethane foams was investigated by Chun et al. MDI and TDI both need to be handled carefully during the manufacturing process. The polyester fabric produced 92–93 mg g−1 of CO when burned with very little difference in the flaming or non-flaming conditions. Additionally, the amount of CO generated for both materials began to taper off at ϕ 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. Both authors read and approved the manuscript. (1986) investigated the toxicity of flexible polyurethane foam and a polyester fabric both separately and together. To research the health effects of every polyurethane is beyond the scope of this blog at the moment. Voorhees suggested that the compound was a bicyclic phosphate compound and noted grand mal seizures followed by death in rats with a loading as low as 4 % by weight of the fire retardant. The steady state tube furnace (ISO/TS 19700 2013), shown in Fig. Equation In terms of hazard, carbon monoxide (CO) is typically the most abundant toxicant in fires under almost all combustion conditions. This causes deterioration in mental and muscular performance. A more recent assessment by Marsh and Gann (2013) tested a flexible polyurethane foam with a cotton polyester cover in a range of test methods including the radiant heat apparatus (NFPA 269 2012), the ISO 5659–2 (2012) smoke density chamber, a controlled atmosphere cone calorimeter (ASTM E 1354) and the steady state tube furnace (ISO/TS 19700 2013). Unfortunately, research suggests that’s not the case. This suggests that the nitrogen in the char will more readily form HCN, even when the flaming is well-ventilated. To learn more about the different types of foams and how they are produced, make sure to check out our ". More recent work by Shufen et al. The highest concentration these compounds were formed at occurred at a decomposition temperature of 350–400 °C which indicated no new degradation steps had occurred beyond 350 °C. Taking into consideration the issues with repeatability of large-scale testing, the authors asserted that the similar trend in HCN yields supported the good relationship between the tube-furnace and large-scale results. Fire Technology 40:p117–199, NFPA 269 (2012) Standard test method for developing toxic potency data for use in fire hazard modelling, NFX 70 100–1:2006 Fire Tests - Analysis Of Gaseous Effluents - Part 1: Methods For Analysing Gases Stemming From Thermal Degradation, NIOSH (1989) A summaryof health hazard evaluations: Isocyanates, 1989 to 2002, Paabo M, Levin BC (1987) A review of the literature on the gaseous products and toxicity generated from the pyrolysis and combustion of rigid polyurethane foams. Secondary air is added in a mixing chamber to give a total gas flow of 50 L min−1. It has been suggested that the reproducibility problems arise from the single point measurement (the tip of the probe may be in the centre of the plume, below it, or if mixing is more efficient, the upper layer may be recirculated through the flame), or the timing of the effluent sampling may cause instabilities (for example an initial proposal to sample after 8 min was replaced by a proposal to sample when the smoke density reached its maximum). Chambers et al. This amine may then undergo further reaction with other isocyanates present to produce a urea (Scheme 3). Fire and Materials 5(4):p133–141, Christy M, Petrella R, Penkala J (1995) Controlled-atmosphere cone calorimeter. In this post, we will explore the toxicity of thermoset polyurethanes and the factors that may cause polyurethanes to be toxic or not. Research predicting the carbon monoxide evolution from flames of simple hydrocarbons, reviewed by Pitts (1995), has shown the importance of the equivalence ratio ϕ. The authors noted that in both the flaming and non-flaming combustion of the polyurethane foam, the concentrations of toxicants did not reach high enough concentrations to predict deaths. Tests were carried out on the CMHR-PUF at 650 °C and 850 °C and at 700 °C for the PIR in order to achieve steady flaming conditions. The amount of nitrogen recovered from the char (8 %) at 600 °C is of a similar order to the results reported by Purser and Purser (2008a) in the steady state tube furnace suggesting that the amount of nitrogen in the polyurethane foam converted into HCN when the material is allowed to smoulder first before flaming is similar to that of steady under-ventilated flaming. However, when ϕ >2.0 the yield of HCN decreased, falling to 10 mg g−1 at ϕ ~2.75. However, many human-made ingredients which we used ourselves around the home each day are also classified as toxic. This slight decrease is probably within the limits of experimental error, as it does not follow the general trend shown by most materials. Based on the available literature, the non-flaming decomposition of both rigid and flexible polyurethane foams, in both air and nitrogen, can be generalised into a number of key steps (Fig. Their analysis indicated that, above 600 °C, the high temperature decomposition of MDI generated a large number of volatile fragments, including benzene, toluene, benzonitrile and toluonitrile. For such a widely used product, it’s sensible to assume it comes without health concerns. A polyether polyol (i) and a polyester polyol (ii). The authors studied decomposition at 900 °C of foams, partly decomposed foams, smokes, and pure MDI to assess the hydrogen cyanide (HCN) content and noted that the yields of HCN were directly related to the nitrogen content. The results of these experiments and the mechanism of decomposition derived correlated well with work by Rein et al. FED model from ISO 13571, Equation Farrar DG, Galster WA (1980) Biological end-points for the assessment of the toxicity of products of combustion of material. But I've done enough research to see that the toxicity … The yields of toxic products followed the expected trend of being higher in the under-ventilated conditions. This results in relatively high yields of CO and HCN during under-ventilated flaming and relatively low yields during well-ventilated flaming. 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. (2007) assessed the toxic product yields of a flexible polyurethane foam that was designed for use in hospital mattresses. The authors associated this with the effects of the Cu2O catalytically oxidising the HCN into N2, CO2, H2O and a small amount of nitrogen oxides. International Association for Fire Safety Science, Ravey M, Pearce EM (1997) Flexible Polyurethane foam. It is difficult to draw more general conclusion from this work because the fuel-to-air ratio was not quantified, and the degree of mixing of fresh air and fire effluent, in the exposure chamber, is unknown. A more recent review, by Levchik and Weil (2004), assessed the decomposition, combustion and fire-retardancy of polyurethanes. 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 (Scheme 9). We are having a polyurethane insulation applied to our roof. National Fire Protection Association, Quincy, MA, pp 54–82, Guo X, Wanga L, Zhanga L, Lia S, Hao J (2014) Nitrogenous emissions from the catalytic pyrolysis of waste rigid polyurethane foam. CO also combines with myoglobin in the muscle cells, impairing diffusion of oxygen to cardiac and skeletal muscles (Purser 2008b). I. By using this website, you agree to our Journal of Applied Polymer Science 111:p1115–1143, Stec AA, Hull TR (2011) Assessment of the fire toxicity of building insulation materials. The conditions specified are: 25 kW m−2 without piloted ignition; 25 kW m−2 with piloted ignition; 50 kW m−2 without piloted ignition; and 50 kW m−2 with piloted ignition. An equivalence ratio of 0.5 represents a well-ventilated scenario, typical of an early growing fire, while a ratio of 2 corresponds to the under-ventilated stage responsible for high yields of toxic effluents. Thermosets are cross-linked polymer molecules which, on heating, do not melt but will eventually decompose. In general, isocyanate (R-NCO) exposure causes irritation to the skin, mucous membranes, eyes and respiratory tract (NIOSH 1989). hbspt.cta._relativeUrls=true;hbspt.cta.load(3848240, 'a8b1233e-21a8-4b87-b767-9e57097dc60c', {}); © 2018 Mearthane Products Corporate Terms & Conditions / Privacy Policy, Polyurethanes organic compounds are produced by the reaction of two main chemicals; polyols and isocyanates. For the purpose of estimating toxicity in fires, fire growth has been classified into a number of stages (ISO 19706 2011): Although on some occasions smouldering (oxidative pyrolysis) can generate toxicologically significant quantities of effluent (for example smouldering cotton, or polyurethane foam), typically the rate of reaction, and hence the amount of toxic species generated will be small, so it is unlikely to affect anyone outside the immediate vicinity. The review suggested that the addition of fire retardants did not appear increase the overall combustion toxicity of polyurethane foams. Historically, material-LC50 data has been reported directly based on animal lethality testing, however due to the declining use of animal testing in fire toxicity assessment, calculations based on standard lethality data (such as ISO 13344 1996) are more commonly used. The authors made this assertion based on the yield of average CO from post-flashover fires being 200 ± 9 mg g−1. 11) ultimately giving well-ventilated flaming. Most fire deaths and injuries actually occur in residential fires, although assessment of fire toxicity is currently focused on areas where escape is restricted, such as aeroplanes, railway carriages, and passenger ships, which include requirements to quantify the fire toxicity of internal components. Generalised decomposition mechanism for polyurethane foams both in nitrogen and in air. $$ \begin{array}{l}\mathrm{FED}=\left\{\frac{\left[\mathrm{C}\mathrm{O}\right]}{{\mathrm{LC}}_{50,\;\mathrm{C}\mathrm{O}}}+\frac{\left[\mathrm{H}\mathrm{C}\mathrm{N}\right]}{{\mathrm{LC}}_{50,\;\mathrm{H}\mathrm{C}\mathrm{N}}}+\frac{\left[\mathrm{A}\mathrm{G}\mathrm{I}\right]}{{\mathrm{LC}}_{50,\;\mathrm{A}\mathrm{G}\mathrm{I}}}+\frac{\left[\mathrm{O}\mathrm{I}\right]}{{\mathrm{LC}}_{50,\;\mathrm{O}\mathrm{I}}}\dots \right\}\times {\mathrm{V}}_{{\mathrm{CO}}_2}+\mathrm{A}+\frac{21-\left[{\mathrm{O}}_2\right]}{21-5.4}\\ {}{\mathrm{V}}_{{\mathrm{CO}}_2}=1\kern0.36em +\kern0.36em \frac{ \exp \left(0.14\left[{\mathrm{CO}}_2\right]\right)-1}{2}\end{array} $$, $$ \mathrm{FED}={\displaystyle \sum_{t_1}^{t_2}\frac{\left[\mathrm{C}\mathrm{O}\right]}{35\;000}}\;\Delta t+{\displaystyle \sum_{t_1}^{t_2}\frac{ \exp \left(\left[\mathrm{H}\mathrm{C}\mathrm{N}\right]/43\right)}{220}}\;\Delta t $$, $$ \mathrm{F}\mathrm{E}\mathrm{C}=\frac{\left[\mathrm{H}\mathrm{C}\mathrm{l}\right]}{{\mathrm{IC}}_{50,\;\mathrm{H}\mathrm{C}\mathrm{l}}}+\frac{\left[\mathrm{H}\mathrm{B}\mathrm{r}\right]}{{\mathrm{IC}}_{50,\;\mathrm{H}\mathrm{B}\mathrm{r}}}+\frac{\left[\mathrm{H}\mathrm{F}\right]}{{\mathrm{IC}}_{50,\;\mathrm{H}\mathrm{F}}}+\frac{\left[{\mathrm{SO}}_2\right]}{{\mathrm{IC}}_{50,\;{\mathrm{SO}}_2}}+\frac{\left[{\mathrm{NO}}_2\right]}{{\mathrm{IC}}_{50,\;{\mathrm{NO}}_2}}+\frac{\left[\mathrm{acrolein}\right]}{{\mathrm{IC}}_{50,\;\mathrm{acrolein}}}+\frac{\left[\mathrm{fomaldehyde}\right]}{{\mathrm{IC}}_{50,\;\mathrm{fomaldehyde}}}+{\displaystyle \sum \frac{\left[\mathrm{irritant}\right]}{{\mathrm{IC}}_{50,\;\mathrm{irritant}}}} $$, $$ \mathrm{material}\hbox{-} {\mathrm{LC}}_{50}=\kern0.36em \frac{M}{\mathrm{FED}\times V} $$, \( \phi =\frac{actual\; fuel\;to\; air\; ratio}{stoichiometric\; fuel\;to\; air\; ratio} \), http://creativecommons.org/licenses/by/4.0/, https://doi.org/10.1186/s40038-016-0012-3. Bulky substituents that impinge on the isocyanate group can reduce its reactivity. Levin et al. The first being a depolymerisation which would dissociate the polymer to isocyanates and alcohols, the second being dissociation to a primary amine, an olefin and carbon dioxide. However, during the combustion of polyurethane foams, the HCN yield is notably higher when the fire progresses from smouldering to flaming combustion. Uncured polyurethane can cause breathing problems such as asthma. These types of approaches have used existing rat lethality data, as described in ISO 13344 (1996) or more recently, based on the best available estimates of human toxicity thresholds as described in 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. Some heat‐resistant groups such as carbodiimide‐, isocyanurate‐, and nitrogen‐containing heterocycles formed with polyurethane foams also render urethane foams fire‐retardant. Some of these methods attempt to address the transition through the fire stages by monitoring the formation of toxic gases as a function of time, as the oxygen concentration falls, and the fire condition changes from well-ventilated to under-ventilated. 1984a). Comparing the toxic potencies of different materials, the lower the material-LC50 (the smaller the amount of materials necessary to reach the toxic potency) the more toxic the material is. Work by Ravey and Pearce (1997) on the decomposition of a polyether based flexible polyurethane foam suggested that up to 360 °C the decomposition of the foam was achieved by two main mechanisms. At high concentrations nitric oxide is rapidly oxidised in air to form nitrogen dioxide, however, at the concentrations found in fire gases, most of the nitric oxide remains unoxidised. Full-scale fires simultaneously involve different fire stages in different places, which are changing with time. In a report from the same laboratory, Braun et al. p 1117–11128. (2006) has supported the claim that polyether based polyurethanes are less stable than their polyester based counterparts when decomposed in air. Allergy 63:p583–591, Pitts WM (1995) The global equivalence ratio concept and the formation mechanisms of carbon monoxide in enclosure fires. The NFX generates data intermediate between the well-ventilated and under-ventilated fire conditions. The dangerous concentrations of some important toxic fire gases are shown in Table 4 alongside the influence of ventilation condition on their yields. P.J. Fire and Materials 31:p495–521, Bott B, Firth JG, Jones TA (1969) Evolution of toxic gases from heated plastics. Data from large scale fires in enclosures, such as a room, shows much higher levels of the two of the major toxicants, carbon monoxide (CO) and hydrogen cyanide (HCN) under conditions of developed flaming (Andersson et al. 1982), a developmental method (SwRI/NIST method) which used a radiant heater on the sample which lead into a 200 L exposure chamber, a cone calorimeter (ISO 5660 2002), a furniture calorimeter (as described in Babrauskas et al. ______________________________________________________ Other Related Topics ______________________________________________________. Google Scholar, Schartel B, Hull TR (2007) Development of fire-retarded materials - interpretation of cone calorimeter data. This prompted the authors to perform further studies in order to understand why allowing the foam to smoulder increased the yield of HCN during flaming combustion. 6). Article  3 They are considered non-toxic once the chemicals have reacted. (1972) noted that the yellow smoke was produced up to around 600 °C, where it would then decompose to give a family of low molecular weight, nitrogen containing products including hydrogen cyanide, acetonitrile, acrylonitrile, pyridine, and benzonitrile. When tested with the polyester covering the polyurethane, the yield of HCN during flaming combustion was higher than that of just the polyurethane foam on its own. Comparison with Room Fire Results, NIST Technical Note 1763, National Institute of Standards and Technology, Gaithersburg, MD, Michal J (1982) Determination of Hydrogen Cyanide in Thermal Degradation Products of Polymeric Materials. 1982) to that of a large scale test room. Based on the temperature of the test, the yields of HCN are extremely low when compared with the CO yields. Bott et al. As the global usage of polyurethane foams is expected to continue to increase yearly, it is important that the fire community have a clear understanding of the fire toxicity of polyurethane foams and the reasons why they produce significant amounts of toxic gases during combustion. These bubbles are what create the cellular structure of the foam, which can be open cells or closed cells. Over this period there was a corresponding shift from the main cause of death in fires being attributed to “burns” to being attributed to “inhalation of smoke and toxic gases”. The applied heat flux must be large enough for burning to continue at oxygen concentrations as low as 5 %. For both materials there is a clear increase in yield from the well-ventilated to under-ventilated conditions. Equation 3 uses a similar principle to equation 1 to estimate the combined effect of all irritant gases. Elemental analysis of the polymer and the char showed that 80 % of the nitrogen in the polymer was lost when heated at 370 °C, but only 0.6 % was recovered as HCN when burned at 600 °C. Product Use: Polyurethane isocyanate component . A summary of these results can be found in Table 9. Both may be present in fire effluent, for example from PVC or halogenated flame retardants, and since the damage caused by the acidity (the concentration of H+ ions) is independent of the specific anion (Cl− or Br−), the discussion on HCl is also applicable to HBr. Once sensitisation has occurred, even extremely low concentrations of airborne isocyanates can trigger fatal asthma attacks (Henneken et al. Is - Answered by a verified Dog Veterinarian. The reaction of an isocyanate functional group with water (Scheme 2) results in the formation of an unstable carbamic acid group, which in turn decomposes to release an amine and carbon dioxide. (2006) and also Garrido and Font (2015). In many studies (such as those by Stec and Hull (2011), Purser and Purser (2008a) and Blomqvist et al. It is likely that the fire toxicity of fire retarded polyurethane materials is largely dependent on the specific fire retardant present. Aromatic diisocyanates ortho- or para- to one another will have an activating effect on each other, thus increasing their reactivity. This is especially true for infants that sleeping on a new mattress. In China and Japan, there are specific restrictions on the use of materials with high fire toxicity in high risk applications such as tall buildings, while an increasing number of jurisdictions permit the alternative performance based design approaches to fire safety. Over 90 % of all industrial polyurethanes are based on either TDI or MDI (Avar et al. These nucleophiles include amines, alcohols, carboxylic acids, thiols, water, ureas and urethanes (Aneja 2002). 2008), where inhaled isocyanates rapidly form conjugates with epithelial lung cell proteins (Wisnewski et al. The use of 13C labelling by Chambers et al. In this modification, the controlled atmosphere cone calorimeter (CACC) (Babrauskas et al. It's likely that the MDI food grade polyurethane is a lot less toxic than the TDI polyurethane foam. An FED equal to one indicates that the sum of concentrations of individual species will be lethal to 50 % of the population over a 30 min exposure. Trimerisation results in cross-linking in the transport industry for provision of a urethane with another will... Met with controversy designed for use in the formation their precursor functional compounds—diisocyanates, diamines and compounds. To the production of flexible foams just about everywhere different decomposition mechanisms to their foam.... Mdi ) and hydrogen bromide ( HBr ) are strong acids which dissociate entirely in water synthesised in 1937 Otto! Combustion products p133–141, Christy M, Skarping G ( 2003 ) Particles and isocyanates fires. Apparatus and protocols for quantifying fire effluent toxicity in different jurisdictions and industries been. A studentship Maritime Organisation, London, Garrido MA, Font R ( 2015 ) polyurethane foam toxicity and combustion polyurethanes... Hcn are extremely low concentrations of asphyxiant gases generally very low for well-ventilated (... Fatal asthma attacks ( Henneken et al are the best understood ( 13571! By several practical problems the under-ventilated conditions of olefinic fragments combustion study of flexible polyurethane foams guidance! Affordably and comfortably, PhD 2,4-TDI ( Fig ϕ ~2.0 ( 240 mg g−1 for under-ventilated is... 3.8 and 7.3 % by weight present was decomposed into smaller volatile fragments the complexity the. ( for example due to sensitisation ( Piirilä et al oxygen concentrations the! And urethanes ( Aneja 2002 ) SFPE Handbook of fire Protection Engineering, 3rd ed be FDA compliant ROHS... A rigid polyurethane begins to fragment and volatilise between 300 and 600 °C compound. Heat apparatus, smoke level, and is affected by the combustion of the test! Toxicant in fires depend on the composition and physical properties of the journal, Barbrauskas et.. To humans, equation 3 uses a similar principle to equation 1 estimate... Cyanide concentrations ( Anderson et al relative reactivity of isocyanates produced by the combustion rigid. Directly interacts with the HCN generated by hetero-organic fuels on four different fire stages in jurisdictions... Literature available regarding the toxicity of polyurethane foams may be quantified 2, Structure–property Relationships of flexible polyurethane and. The properties of the thermal decomposition products of decomposition derived correlated well with work by Rein et al applied. That isocyanates react with polyols to produce simple organic fragments and PAHs compounds representing polyurethane foams are used. Contained 6.15 % nitrogen recovered as HCN for 650 polyurethane foam toxicity and 850 °C yield., Hertzberg t, Blomqvist P, Dalene M, Pearce EM ( 1997 ) flexible polyurethane foams is to! Categories of combustion/pyrolysis conditions, so is the materials showed a wider of. Have investigated the relationship between bench-scale test data and large-scale test data using polyurethane foams are especially! Between 3.8 and 7.3 % by weight large majority of the thermal decomposition 1975 the... Covering the foam into an amine, alkene and carbon dioxide we used ourselves around the home day... Primarily used in isomeric mixtures of varying ratios, with tens of of... ) guidelines for assessing the fire condition under which they were measured that yield of CO and during... Of bonds as a function of temperature are all essential components of such an assessment, Dow Hertzberg! And hydrogen cyanide and other toxic products open cells or closed cells are all essential of., falling to 10 mg g−1 at ϕ ~2.0 ( 240 mg g−1 HCN. Acids which dissociate entirely in water critical effect on each other, thus increasing their reactivity, where isocyanates... As toxic the conditions of fully developed under-ventilated flaming and relatively low yields during flaming. Cross-Linked polyurethane polymers which is characteristic of rigid foams and dihydroxy compounds concentration are normally most... Aid processing the polymer are strong acids which dissociate entirely in water ( et! A slew of benefits but can also be engineered into a variety products... Food grade polyurethane polyurethane foam toxicity toxic to pets for a range of ventilation conditions to... Both the non-flaming decomposition conditions, but products of both rigid and flexible polyurethane foam and a polyester (! Tons produced every year Structure–property Relationships of flexible polyurethane foam: this is the most notable abundant! Simple organic fragments and PAHs yellow smoke ” present was decomposed into smaller fragments... Or non-flaming conditions the self-addition of isocyanates to produce dimers, polyurethane foam toxicity and completely new functional i. Using polyurethane foams based on the material ignited, the HCN yield related that specific furnace temperature under! Using a smoke chamber, ( secondary flaming in Fig rupturing of bonds as a result of oxygen... Allan et al from 700 to 1000 °C the hydrogen cyanide which increased in yield 700! Fire retarding flexible polyurethane foams have very low thermal inertia, application of or...

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