The prediction of combustion products

Woolley, W.D.; Fardell, P.J.

doi:10.1016/0379-7112(77)90004-2

Cited by 20 publications

(28 citation statements)

References 3 publications

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“…Generally speaking at temperatures above 700 C many decomposition products are unstable and relatively simple atmospheres of low molecular weight products are formed, whereas at lower temperatures larger molecular fragments and denser smokes are formed [6,12]. Although this was true of the three materials examined, the patterns of thermal decomposition of the two nitrogen containing polymers, polyacrylonitrile and flexible polyurethane foam showed considerable differences.…”

Section: Results Of Experiments With Polymeric Materialsmentioning

confidence: 90%

“…Studies of thermal decomposition and combustion products of a wide range of materials under both large and small scale fire conditions [6,7] have shown them to contain a variety of potentially toxic chemical species. Some, such as carbon monoxide and hydrogen cyanide, are narcotic and can incapacitate occupants in a fire by affecting the nervous and cardiovascular systems, while others are irritant and incapacitate by effects upon the eyes and upper and lower respiratory tracts causing respiratory distress and behavioural incapacitation.…”

Section: Introductionmentioning

confidence: 99%

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Biological Studies of Combustion Atmospheres

Purser

Woolley

1983

Journal of Fire Sciences

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There is evidence supported by statistical information from fire deaths that many fire fatalities occur as a result of incapacitation of the victims by the toxic products given off during the early stages of fires, thereby preventing escape from the fire, rather than from direct exposure to heat or other factors. As an essential part of understanding these problems, a study has been made of the mechanisms of incapacitation resulting from exposures to atmospheres of thermal decomposition products from polymeric materials. Under conditions approved by the Home Office Inspector, individual cynomolgus monkeys were exposed to atmospheres increasing in separate experiments from very low smoke concentrations until early signs of physiological effects were detected. Measurements were made of two kinds of physiological parameters: vital signs (respiration, electrocardiography and respiratory blood gases) and parameters indicating effects on the nervous system (electroencephalography, auditory evoked potentials, nerve conduction velocity). The atmospheres generated were designed to study the effects of hypoxia, hypercapnia, carbon monoxide, hydrogen cyanide and thermal decomposition products from wood, polyacrylonitrile, polyurethane foam, polypropylene, polystyrene and nylon produced under pyrolytic or oxidative conditions at a range of temperatures. The main findings were that the composition and hence the toxicity of the products from individual materials could vary considerably depending upon the different conditions of temperature and degree of oxygenation under which they were decomposed. However, despite the great complexity in chemical

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Section: Results Of Experiments With Polymeric Materialsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Biological Studies of Combustion Atmospheres

Purser

Woolley

1983

Journal of Fire Sciences

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“…For flexible polyurethane foams it is known that a proportion of fuel nitrogen escapes combustion by being released into the effluent plume as an isocyanate-derived component while for rigid foams such as PIR the nitrogen is trapped in the burning solid [14].…”

Section: Discussionmentioning

confidence: 99%

HCN yields and fate of fuel nitrogen for materials under different combustion conditions in the ISO 19700 tube furnace and large -scale fires

Purser¹,

Purser²

2008

Fire Saf. Sci.

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For calculations of time-concentration curves for toxic products in full-scale fires it is necessary to know how the yields of key toxic species vary with combustion conditions and fuel composition. In this paper, the relationships between equivalence ratio (phi) and HCN yields and conversion efficiencies (mass fraction of fuel nitrogen released as HCN) are presented for ten common nitrogen-containing materials and products combusted in the ISO19700 tube furnace under steady flaming conditions at a furnace temperature of 650-700°C in air. Additional experiments were carried out at 850°C and also in 10% and 12% oxygen. Large-scale fire tests were carried out under well-ventilated and vitiated combustion conditions on three materials for comparison. For non-FR materials sigmoid relationships between phi and HCN yields were found with very low yields (0.00003-0.002 g/g) at phi 0.5 increasing to a wide range (0.0036 g/g to 0.11 g/g) at phi 2 depending upon the material. Yields from some materials were also found to be sensitive to furnace temperature and oxygen concentration. When normalised for nitrogen content, the relationships between phi and HCN recovery were more similar, falling into high (maximum HCN recovery fraction ~ 0.16) and low groups (maximum 0.085). Although the large-scale test data were more variable, a good agreement was found with the tube-furnace results.

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“…At ϕ~2.0 the CMHR-FPUR resulted in 8 % and 11 % nitrogen recovered as HCN for 650°C and 850°C respectively. The authors acknowledged that the lower nitrogen recovery fraction for the flexible foam could be due to fuel nitrogen being lost as isocyanates, which are known to escape into the effluent plume, while for rigid foams they are more likely to be trapped in the burning solid (Woolley & Fardell 1977). For the range of materials investigated, the authors also noted that those containing fire retardants (including the CMHR-PUF and PIR) resulted in a higher recovery fraction of fuel N as HCN.…”

Section: −1mentioning

confidence: 78%

The fire toxicity of polyurethane foams

2016

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Polyurethane is widely used, with its two major applications, soft furnishings and insulation, having low thermal inertia, and hence enhanced flammability. In addition to their flammability, polyurethanes form carbon monoxide, hydrogen cyanide and other toxic products on decomposition and combustion. The chemistry of polyurethane foams and their thermal decomposition are discussed in order to assess the relationship between the chemical and physical composition of the foam and the toxic products generated during their decomposition. 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. The methods of assessment of fire toxicity are outlined in order to understand how the fire toxicity of polyurethane foams may be quantified. In particular, the ventilation condition has a critical effect on the yield of the two major asphyxiants, carbon monoxide and hydrogen cyanide.

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The prediction of combustion products

Cited by 20 publications

References 3 publications

Biological Studies of Combustion Atmospheres

Biological Studies of Combustion Atmospheres

HCN yields and fate of fuel nitrogen for materials under different combustion conditions in the ISO 19700 tube furnace and large -scale fires

The fire toxicity of polyurethane foams

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