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 56592 (2012) smoke density chamber, a controlled atmosphere cone calorimeter (ASTM E 1354) and the steady state tube furnace (ISO/TS 19700 2013). 2023 BioMed Central Ltd unless otherwise stated. statement and P.J. The transport industries have adopted the smoke density chamber (SDC) ISO 56592 (2012) and ASTM E662, for quantification of toxic product yields (Fire Test Procedure Code 2010; CEN/TS 455452 2009) using simple pass/fail chemical detection (e.g. Centre for Fire and Hazard Science, University of Central Lancashire, Preston, PR1 2HE, UK, Sean Thomas McKenna&Terence Richard Hull, You can also search for this author in The PIR at 1.75 resulted in 15% of the fuel nitrogen being recovered as HCN. The products generated in the flame zone then pass through the heated furnace tube, maintaining a high temperature, as in the upper layer of a compartment fire. 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. Most rigid foams and speciality polyurethanes use polymeric MDI derivatives which are mixtures components such as dimers and trimers (Fig. When polyurethane foam insulation burns it gives off toxic gasses, very high temperatures and large amounts of thick, black smoke. The resulting substituted urea can then react with another isocyanate to pro-duce a biuret linkage (Scheme 4). Is Your Mattress Releasing Toxins While You Sleep? - WebMD The danger of using urethane products is when the foam burns. Fire Safety Journal 43:243251, Piiril PL, Meuronen A, Majuri ML, Luukkonen R, Mntyl T, Wolff HJ (2008) Inflammation and functional outcome in diisocyanate-induced asthma after cessation of exposure. In the large scale test room, the sample smouldered for 1.5 to 2h, resulting in a HCN yield of 1.03mgg1. At lower temperatures, decomposition differs, depending on the composition and physical properties of the polymer, although clear trends can be identified. Heat, smoke and irritant gases may impair escape, increasing the risk of a lethal exposure to asphyxiant gases, andcan sometimes lung damage causes death in those managing to escape. Does Polyurethane Foam Give Off Toxic Fumes? Similarly, well-ventilated fires are generally small, and of low toxicity. The most notable and abundant of these was hydrogen cyanide which increased in yield from 700 to 1000C. Appropriate formulation affords a degree of control over the cross-linking in the polymer without the need for additional cross-linking agents. In general, isocyanate (R-NCO) exposure causes irritation to the skin, mucous membranes, eyes and respiratory tract (NIOSH 1989). While it is evident that the HCN yield increases as a fire becomes more under-ventilated, the link between the nitrogen content of the fuel and the yield of HCN is less clear. 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). 2013). An FED equal to one indicates that the sum of concentrations of individual species will be lethal to 50% of the population over a 30min exposure. . Work by Guo et al. The uptake, distribution, metabolism and excretion of cyanide is much more complex than for CO and quantifying CN- in fire victims is more expensive and not routinely undertaken. Off-gassing. This is unusual as this test method is usually well-ventilated and the results are not similar to reports of other authors (such as Levin et al. 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. 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. Toxic Materials in Foam Mattresses? Are We Safe? Once the material ignited, the yield of HCN increased to 3.8mgg1. the sum of each of the concentrations multiplied by the exposure time, for each product; upper respiratory tract irritants are believed to depend on the concentration alone (Purser 2007). In particular, the ventilation condition has a critical effect on the yield of the two major asphyxiants, carbon monoxide and hydrogen cyanide. By using this website, you agree to our While well-ventilated fire scenarios are routinely used for assessment of flammability, because the object is to stop the fire growing to the out of control stage, where fire toxicity is concerned, the important fire stages are under-ventilated. TDI is primarily used in the production of flexible foams, which are used in the furniture and interior industries. depends on the mass loss rate of the specimen and the available air; for most methods one or both are unknown; will be increased by an unknown factor if products are recirculated into the flame zone. Manage cookies/Do not sell my data we use in the preference centre. Over 90% of all industrial polyurethanes are based on either TDI or MDI (Avar et al. 1982), a developmental method (SwRI/NIST method) which used a radiant heater on the sample which lead into a 200L exposure chamber, a cone calorimeter (ISO 5660 2002), a furniture calorimeter (as described in Babrauskas et al. Short chains with high functionality results in highly cross-linked polyurethane polymers which is characteristic of rigid foams. Flaming combustion of the polyurethane foam did not cause any animal deaths, however the non-flaming combustion resulted in deaths post-exposure. At 300C, free isocyanates and alcohols were produced from the decomposition of these biscarbamates. The polyurethane market was estimated to be worth $33 billion in 2010 and is expected to continue to grow to over $55 billion by 2016. 2), also results in cross-linking in the polymer. It is likely that the fire toxicity of fire retarded polyurethane materials is largely dependent on the specific fire retardant present. New memory foam smell? These VOCs come mainly from the polyurethane used in the mattress, but also from other chemicals used in flame retardants and plastics, the researchers said. 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. The results indicated that the formation of the precursor, TDI, was much faster and preferable to depolymerisation when the volatile compounds could escape. The incapacitating Ct product corresponds to CO at a dose of 35 000LL1min (approximately equal to ppm min), predicting incapacitation at around 1200ppm for 30min exposure, and an exponential relationship for HCN (because asphyxiation by HCN exposure does not fit a linear relationship), predicting incapacitation at around 82ppm for 30min exposure. Diesel engines use the principle of _____ to ignite fuel vapor. (2007). Fire Hazards of Insulation Materials | American Family Insurance More recent work by Shufen et al. The yield of CO had a wide range during the under-ventilated tests due to inconsistent flaming of the sample with yields from 100250mgg1. At 650C, the yield of HCN from the CMHR-PUF increased up to ~2.0 where it reached a peak of 14mg of HCN per gram of polymer burned. The average combined yield of isocyanates recovered was 0.869mgg1 and the average yield of amines and aminoisocyanates was 0.321mgg1. Alongside the experiments performed in the steady state tube furnace, the PIR was also investigated in a half scale ISO 9705 room-corridor test and in a full size ISO 9705 (1993) room. Global usage is expected to expand from 13.65 Mt in 2010 to 17.95 Mt by 2016. Polymer Degradation and Stability 93:p20582065, Tewarson A (2002) SFPE Handbook of Fire Protection Engineering, 3rd ed. For example, Levin and coworkers reported that melamine-treated flexible polyurethane foam generated 6 times more HCN than an equal amount of non-melamine treated foam. Work published as early as 1959 supported this mechanism of decomposition at higher temperatures and noted that up to 70% of the nitrogen in the foam could be converted to HCN at 1000C (Saunders 1959). The toxic product yields may be quantified from the gas concentrations and mass feed rate during the steady state burn period. The rigid polyurethane foam yielded ~55mgg1 CO and ~0.5mgg1 of HCN. Polyol fragments in the gas phase will also begin to decompose at >800C to produce simple organic fragments and PAHs. Polymer-Plastics Technology and Engineering 45:p95108, Singh H, Jain AK (2009) Ignition, Combustion, Toxicity, and Fire Retardancy of Polyurethane Foams: A Comprehensive Review. Equation 2 calculates the FED of the major asphyxiants, CO and HCN, but without taking oxygen depletion or CO2 driven hyperventilation into account. Further decomposition occurred about 600C with the fragmentation of the yellow smoke, primarily into hydrogen cyanide and small quantities of acetonitrile, acrylonitrile and benzonitrile. Fire and Materials 19:p6164, Shufen L, Zhi J, Kaijun Y, Shuqin Y, Chow WK (2006) Studies on the Thermal Behavior of Polyurethanes. More recent studies have supported and expanded upon the aforementioned thermal decomposition mechanisms of polyurethane foams. The rigid polyurethane foam produced slightly more CO than the polyisocyanurate at ~2.0 (240mgg1 vs 225mgg1). Fire and Materials 5(4):p133141, Christy M, Petrella R, Penkala J (1995) Controlled-atmosphere cone calorimeter. The relativelyhigh yields of CO from under-ventilated fires are held responsible for most deaths through inhalation of smoke and toxic gases. Thermal Decomposition of Polyether-based, Water-blown Commerical type of Flexible Polyurethane Foam. 7) (Avar et al. 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. Does the foam give off toxic fumes if burned? This value decreased to 18mgg1 at ~2.0. The CACC and SDC show reasonable agreement for well-ventilated burning, but fail to replicate the more hazardous under-ventilated fire conditions. https://doi.org/10.1186/s40038-016-0012-3, DOI: https://doi.org/10.1186/s40038-016-0012-3. 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. An understanding of the relative reaction rates is vital in controlling the production of the polymer and producing the desired physical properties (Herrington & Hock 1998). At >800C these compounds further fragment into simple molecules (such as HCN, CO, CH4 and CH2O) and PAHs. The toxic product generation during flaming combustion of polyurethane foams is reviewed, in order to relate the yields of toxic products and the overall fire toxicity to the fire conditions. Combustion Science and Technology 183(7):p627644, Saunders JH (1959) the Reactions of Isocyanates and Isocyanate Derivatives at Elevated Temperatures. Bulky substituents that impinge on the isocyanate group can reduce its reactivity. The half-scale ISO 9705 experiments showed a wider range of ventilation conditions up to ~2.0. In the chamber, 0.23g of black char and 0.04g of yellow oil were recovered. Recent work by Allan et al. The detection of the amino MDI derivative in the tar further supports the literature reports of a secondary decomposition mechanism where isocyanates trapped in the condensed phase are converted irreversibly into their amine derivatives. Technology, Gaithersburg MD, Babrauskas V, Levin BC, Gann R, Paabo M, Harris RH, Peacock RD, Yusa S (1991b) Toxic potency measurement for fire hazard analysis, special publication 827, National Institute of Standards and Technology. The guidelines above for choosing a safer mattress or non toxic mattress topper can help determine which . As the toxic product yields of polyurethane foams are directly related to the ventilation conditions, so is the materials LC50 value. Again, above 600C the compound and any yellow smoke present was decomposed into smaller volatile fragments. Work by Ravey and Pearce (1997) on the decomposition of a polyether based flexible polyurethane foam suggested that up to 360C the decomposition of the foam was achieved by two main mechanisms. However, there is verylittle literature available regarding the yields of isocyanates produced by the combustion of polyurethane foams. Top of Page. The full size ISO 9705 test resulted in well-ventilated flaming ( 0.260.5) due to the relatively large volume of air and relatively small sample size. 1982), and a three-compartment large scale test. Progressive changes in the composition of a static specimen (for example due to char formation) provide additional complexity. CO and HCN are the main asphyxiants produced during the combustion of polyurethanes and there have been a large number of studies published regarding their yields. 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). 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. The authors would like to thank Dr. Linda Bengtstrom for her contribution regarding the toxicity of isocyanates. 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. Fire Safety Science Proceedings of the ninth international symposium. National Fire Protection Association, Quincy, MA, pp 5482, Guo X, Wanga L, Zhanga L, Lia S, Hao J (2014) Nitrogenous emissions from the catalytic pyrolysis of waste rigid polyurethane foam. In an attempt to improve the understanding of the thermal decomposition of polyurethanes, Rogaume et al. 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. 1984a). Investigator Chapters 1-5 --PART 1--Burns Flashcards | Quizlet 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. In this case, the main reason for including isocyanate reactivity data is to explain the reactivity of isocyanates that are released into fire effluent during combustion. The presence of Cu2O drastically decreased the yield of HCN in polyurethane foams at lower temperatures, but had little effect at high temperatures. The average well-ventilated yield of HCN was found to be 4mgg1, while it was 9mgg1 for under-ventilated conditions. Once sensitisation has occurred, even extremely low concentrations of airborne isocyanates can trigger fatal asthma attacks (Henneken et al. However, in the field of combustion toxicity testing, this under-ventilated burning is the most difficult to create using bench-scale apparatus. Under well-ventilated flaming (<0.8), the yields of CO2 and NO2 were at their highest, while the yields of CO and HCN were at their lowest. ISO 13571 (2007) considers the four major hazards from fire which may prevent escape (toxic gases, irritant gases, heat and smoke obscuration). The lowest temperature at which a liquid will give off vapors at a sufficient rate to support a momentary flame across its surface is known as its: . Insulation, like all building products, has an 'embodied' carbon footprint resulting from energy use during the manufacturing process. Interflam Conference Proceedings. Urethane Foam Health Effects | livestrong However, many people fail to escape from fires because of the incapacitating effect of smoke (obscuring visibility) and its irritant components which cause pain, preventing breathing and escape or reason death occurred. to FED. CORE - Aggregating the world's open access research papers The process of . ISO 19706 (2011) Guidelines for assessing the fire threat to people. In contrast to the relativelywell-defined effects of asphyxiants, the effects of exposure to irritants are more complex. That smell comes from volatile organic compounds, or VOCs, chemicals used in the mattress manufacturing process. In the smoke chamber, the highest reported yield during flaming combustion was 1.02mgg1. (2006) and also Garrido and Font (2015). Do memory foam mattresses give off toxic fumes? Various apparatus and protocols for quantifying fire effluent toxicity in different jurisdictions and industries have been critically reviewed (Hull & Paul 2007). 5). Will polyurethane melt under heat? - remodelormove.com Aromatic isocyanates are more reactive than aliphatic isocyanates due to the electronic effects of the aromatic ring.