Further to this, a similar pattern began to emerge in the injuries of fire victims (Fig. 23. Is Memory Foam Toxic? | Sleep Foundation The data also does not specify the fire retardants used. Additionally, aromatic isocyanates with more steric hindrance are likely to be less reactive (such as the 2 position in 2,4-TDI (Fig. 2012). Isocyanates also react with themselves in various ways to produce dimers, trimers and completely new functional groups. In air, the resulting decomposition fragments can be oxidised into CO, CO2, H2O and nitrogen oxides at high temperatures. Flaming combustion of the polyurethane foam did not cause any animal deaths, however the non-flaming combustion resulted in deaths post-exposure. EN 2826. Since serious fires involving the use of these materials have occurred on several ships, the United States Coast Guard has issued a Navigation and Vessel Inspection Circular No. 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. Anal Bioanal Chem 387:p219236, Herrington R, Hock K (1998) Flexible Polyurethane Foams, 2nd edn. The review refers to a publication by Babrauskas et al. 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). In general, How do low-density materials (such as polyurethane foam) burn compared to higher-density materials (cotton padding) of similar makeup? 14) (UK Fire Statistics 2013). 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. In this modification, the controlled atmosphere cone calorimeter (CACC) (Babrauskas et al. The authors acknowledged that further investigation of the steady state tube furnace was warranted as in some of the testing they suspected an instrumental error, since they were unable to account for roughly two-thirds of the total carbon from the sample and detected unusually low levels of CO2 during the under-ventilated tests. Since then, Blais and Carpenter (2015) investigated a flexible polyurethane foam with and without a chloro phosphate (tris-dichloro-propyl phosphate TDCPP) fire retardant using a smoke box (ISO 56592 2012) to assess the toxicity. NBSIR 822532. This slight decrease is probably within the limits of experimental error, as it does not follow the general trend shown by most materials. 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. PDF Fire Properties of Polyvinyl Chloride It forces combustion by driving the sample into a furnace of increasing heat flux at a fixed rate, so that, by running several tests with the same material with different ventilation conditions, each fire stage can be replicated by steady state burning. Therefore, the products of decomposition can be predicted from the composition of the polymer. However, bench-scale methods which allow the combustion conditions to change during the test are much more difficult to relate to full-scale fires, because the duration of each condition is unknown, and the behaviour of fires changes on scale-up. (2007) assessed the toxic product yields of a flexible polyurethane foam that was designed for use in hospital mattresses. Energy and Buildings 43:p498506, Stec AA, Hull TR (2014) Fire Toxicity Assessment: Comparison of Asphyxiant Yields from Laboratory and Large Scale Flaming Fires. Results from these burn tests are used for comparison with the model developed to simulate flame spread, heat fluxes, and smoke development over time (Figure 1). Its widespread availability has encouraged its adaptation to toxic gas generation and assessment. However, instead of finding my answer I found seemingly endless reports on websites claiming that memory foam gives off potentially toxic fumes. Generalised decomposition mechanism for polyurethane foams both in nitrogen and in air. decomposition products will burn. 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. As polyurethane foams have very low thermal inertia, application of heat or a small flame can be enough to ignite them. 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). 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. 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. This makes the isocyanate functional group highly reactive towards nucleophiles with an available hydrogen. More recent work by Shufen et al. The polyurethanes used were elastomers based on TDI, which could potentially have differing decomposition mechanisms to their foam counterparts. This amine may then undergo further reaction with other isocyanates present to produce a urea (Scheme3). Most bench-scale methods have non-constant combustion conditions, such as those in closed chambers exposed to a constant source of heat, including the smoke density chamber (SDC) (ISO 56592 2012), and static tube furnace tests, such as the NF X 70100 (2006). Analysis of the compound, trimethylol propane phosphate (TMPP), by Kimmerle (1976) found it to have a high acute toxicity when tested on rats. The first is by combination with the ferric ion in mitochondrial cytochrome oxidase, preventing electron transport in the cytochrome system and inhibiting the use of oxygen by the cells. Routes of entry in this case are inhalation, ingestion (saliva), and skin absorption. An equation has been developed for the estimation of the FED for lethality from the chemical composition of the environment in the physical fire(such as the bench-scale methods described in the following section) model taken from ISO 13344 (1996) and uses gas-LC50 values for lethality to provide referencetoxicity data for the individual gases to calculate toxic potency, based on rats exposed for 30min. $$ \begin{array}{l}\mathrm{FED}=\left\{\frac{\left[\mathrm{C}\mathrm{O}\right]}{{\mathrm{LC}}_{50,\;\mathrm{C}\mathrm{O}}}+\frac{\left[\mathrm{H}\mathrm{C}\mathrm{N}\right]}{{\mathrm{LC}}_{50,\;\mathrm{H}\mathrm{C}\mathrm{N}}}+\frac{\left[\mathrm{A}\mathrm{G}\mathrm{I}\right]}{{\mathrm{LC}}_{50,\;\mathrm{A}\mathrm{G}\mathrm{I}}}+\frac{\left[\mathrm{O}\mathrm{I}\right]}{{\mathrm{LC}}_{50,\;\mathrm{O}\mathrm{I}}}\dots \right\}\times {\mathrm{V}}_{{\mathrm{CO}}_2}+\mathrm{A}+\frac{21-\left[{\mathrm{O}}_2\right]}{21-5.4}\\ {}{\mathrm{V}}_{{\mathrm{CO}}_2}=1\kern0.36em +\kern0.36em \frac{ \exp \left(0.14\left[{\mathrm{CO}}_2\right]\right)-1}{2}\end{array} $$, $$ \mathrm{FED}={\displaystyle \sum_{t_1}^{t_2}\frac{\left[\mathrm{C}\mathrm{O}\right]}{35\;000}}\;\Delta t+{\displaystyle \sum_{t_1}^{t_2}\frac{ \exp \left(\left[\mathrm{H}\mathrm{C}\mathrm{N}\right]/43\right)}{220}}\;\Delta t $$, $$ \mathrm{F}\mathrm{E}\mathrm{C}=\frac{\left[\mathrm{H}\mathrm{C}\mathrm{l}\right]}{{\mathrm{IC}}_{50,\;\mathrm{H}\mathrm{C}\mathrm{l}}}+\frac{\left[\mathrm{H}\mathrm{B}\mathrm{r}\right]}{{\mathrm{IC}}_{50,\;\mathrm{H}\mathrm{B}\mathrm{r}}}+\frac{\left[\mathrm{H}\mathrm{F}\right]}{{\mathrm{IC}}_{50,\;\mathrm{H}\mathrm{F}}}+\frac{\left[{\mathrm{SO}}_2\right]}{{\mathrm{IC}}_{50,\;{\mathrm{SO}}_2}}+\frac{\left[{\mathrm{NO}}_2\right]}{{\mathrm{IC}}_{50,\;{\mathrm{NO}}_2}}+\frac{\left[\mathrm{acrolein}\right]}{{\mathrm{IC}}_{50,\;\mathrm{acrolein}}}+\frac{\left[\mathrm{fomaldehyde}\right]}{{\mathrm{IC}}_{50,\;\mathrm{fomaldehyde}}}+{\displaystyle \sum \frac{\left[\mathrm{irritant}\right]}{{\mathrm{IC}}_{50,\;\mathrm{irritant}}}} $$, $$ \mathrm{material}\hbox{-} {\mathrm{LC}}_{50}=\kern0.36em \frac{M}{\mathrm{FED}\times V} $$, https://doi.org/10.1186/s40038-016-0012-3, http://creativecommons.org/licenses/by/4.0/. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. The three-compartment test consisted of a 2.43.72.4m burn room, a 2.44.62.4m corridor and a 2.43.72.4m target room where samples would be taken. Investigator Chapters 1-5 --PART 1--Burns Flashcards | Quizlet The toxic product yields may be quantified from the gas concentrations and mass feed rate during the steady state burn period. 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. eds. 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). NBSIR 822604. California Privacy Statement, (2013) further supported the presence of two separate decomposition mechanisms for flexible foams. A polyether polyol (i) and a polyester polyol (ii). In the chamber, 0.23g of black char and 0.04g of yellow oil were recovered. 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. Toxic Materials in Foam Mattresses? Are We Safe? Free of VOCs and HAPs. Journal of Fire Sciences 8:p6379, BS 6853 (1999) Code of practise for fire precautions in the design and construction of passenger carrying trains. For both materials there is a clear increasein yield from the well-ventilated to under-ventilated conditions. 1981), probably because of increased use of nitrogen-containing synthetic polymers. At 300C, free isocyanates and alcohols were produced from the decomposition of these biscarbamates. Apparatus where changes rapidly allow little time for sampling and measurement of mass loss and effluent compositionat a specific value of, with resultant errors and uncertainties. 2008; Kaplan 1987b). Using a cup furnace with a 200L sampling chamber (identical in design to the one used in the smoke chamber experiments), a 3.88g sample of foam was heated to just below its ignition temperature (370C) which yielded <1mgg1 HCN. 4). The general approach in generating toxic potency data from chemical analysis is to assume additive behaviour of individual toxicants, and to express the concentration of each as its fraction of the lethal concentration for 50% of the population for a 30min exposure (gas-LC50). Thermal decomposition of polyurethanes is usually the reverse of polymerisation, resulting in the formation their precursor functional compoundsdiisocyanates, diamines and dihydroxy compounds. Gaithersberg, MD, Babrauskas V, Twilley WH, Janssens M, Yusa S (1992) Cone calorimeter for controlled-atmosphere studies. The process of . The Steady state tube furnace apparatus, ISO/TS 19700. Work by Guo et al. Fire and Materials 6:p1315, Neviaser JL, Gann RG (2004) Evaluation of Toxic Potency values for Smoke from Products and Materials. However, the yield of CO was lower in both the non-flaming and flaming combustion. Google Scholar, Schartel B, Hull TR (2007) Development of fire-retarded materials - interpretation of cone calorimeter data. As a result of this, studies that use ventilation controlled conditions, such as those using the steady state tube furnace (ISO/TS 19700 2013), are more likely to give a realistic representation of these reduced oxygen environment fire conditions. Does Polyurethane Foam Give Off Toxic Fumes? | Nontoxic Living It can continue to irritate people sensitive to chemicals or odors . (2007)), the sample is raised to a fixed furnace temperature, which is further increased in the gas phase during flaming combustion. Vilar Consultoria Tcnica Ltda, Rio de Janeiro, Voorhees J (1975) Extreme Toxicity from Combustion Products of Fire-Retarded Polyurethane Foam. Journal of Applied Polymer Science 63:p4774, Rein G, Lautenberger C, Fernandez-Pell AC (2006) Application of Genetic Alogorithms and Thermogravimetry to Determine the Kinetics of Polyurethane Foam in Smoldering Combustion. Taking this into consideration, the reported yields of isocyanates, aminoisocyanates and amines are still relevant, as the results of Blomqvist et al. The methods of assessment of fire toxicity are outlined in order to understand how the fire toxicity of polyurethane foams may be quantified. (2007) suggests that their yields are not heavily dependent on the ventilation conditions and that the yields would likely only increase by a small amount during under-ventilated flaming. When =1 the theoretical amount of air is available for complete combustion to carbon dioxide (CO2) and water. By using this website, you agree to our Isocyanurate rings are the most thermally stable in an inert atmosphere and decompose between 270 and 300C. Similarly, Busker et al. Each method is described briefly in the following section. 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.
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