Gas fire

Levin, B.C. Paabo, M. Gurman, J.L. Clark, H.M. Yoklavich, M.F. Further Studies of the Toxicological Effects of Different Time Exposures to the Individual and Combined Fire Gases-Carbon Monoxide, Hydrogen Cyanide, Carbon Dioxide and Reduced Oxygen, Polyurethane 88. Proceedings of the 31— SPI Conference. Philadelphia, PA, 1988, p. 249-252. 

Hartzell, G.E. Grand, A.F. Switzer, W.G. "Modeling of Toxicological Effects of Fire Gases VII. Studies on Evaluation of Animal Models in Combustion Toxicology," J. Fire Sciences 1988, 6(6), 411-431. 

The flow of hot gas out of, and fresh air into, the fire room is shown in Figure 5. The fire room occupant wakes up and escapes at 121 seconds, 12 seconds after the alarm. He leaves the door open so fire gases start to flow out. The outflow increases rapidly to 1.2 kg/sec while the inflow, somewhat later, reaches 1 kg/sec. The outflowing hot layer ga3 carries its fuel content which reaches a maximum of about. 22 kg/sec. 

Once incapacitated, the person falls to the floor and continues to breath CO from the changing fire gases. If a person falls 5 meters (16 ft) from the open end of the corridor, further exposure occurs along the line E-E in Figure 8. This exposure is also plotted in Figure 9. At the incapacitation time (444 seconds, 5 m along corridor), the lethal dose is... 

These studies also pointed out that a potentially very dangerous gas in fires is acrolein, because the ratio of its concentration, as measured in the atmosphere of real fires, to its lethal exposure dose (LED) is higher than for many other common fire gases. The ratios of concentrations... 

Fig. 3.30 LDA analysis of signal patterns of typical fire gases. The data were obtained using a Sn02 microarray equipped with Si02...

Inhaling hot (fire) gases into the lungs will also cause tissue damage to the extent that fatal effects could result in 6 to 24 hours after the exposure. 

Because many materials release HCN when burned, the combined toxicity of HCN and smoke components—carbon monoxide, carbon dioxide, nitrogen dioxide—have been studied. Combination experiments with fire gases showed... 

About 1865, E. Kopp, and P. W. Hofmann tried to revive the oxysulphide theory, but J. Pelouze refuted their arguments and after a long study of the reactions, J. Kolb confirmed A. Scheurer-Kestner s work, but concluded that in the main reaction the calcium carbonate loses its carbon dioxide by the action of the carbon dioxide in the fire gases. A. Scheurer-Kestner then showed that in this last conclusion J. Kolb is in error, because black ash can be made in crucibles without any assistance from the fire gases that the decomposition of the calcium carbonate, even in the presence of coal, requires a higher temp, than the reduction of the sodium sulphide and that black asb is obtained by directly heating sodium sulphide with calcium carbonate. 

Oxygen depletion, also a feature of fire gases, can be lethal once oxygen concentration has fallen below tenable levels (-6%). However, from a fire toxicity perspective it is generally assumed that... 

If the effluent is stratified, the gas sample is obviously unrepresentative, but if it is uniformly distributed, then the gas flowing into the fire zone may be oxygen depleted and fire gases may be recycled through the fire zone. These latter effects will be greater with thicker specimens, which would be expected to generate more smoke, due to more complete consumption of oxygen and hence to under-ventilation. 

Babrauskas, V., Effective measurement techniques for heat, smoke and toxic fire gases, International Conference FIRE Control the Heat-Reduce the Hazard, Fire Research Station, October 24—25, London, U.K., 4, 1988. 

Hartzell, G.E., H.W.Stacy, W.G.Swiztzer, D.N.Priest, and S.C.Packham. 1985. Modeling of toxicological effects of fire gases 4. Intoxication of rats by carbon monoxide in the presence of an irritant. J. Fire Science. 3 263—279. 

---