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http://hdl.handle.net/123456789/646
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| Title: | Toxic species in compartment fires |
| Authors: | Kumar, Rajiv
Singh, M P
Sharma, Sunil K
Kumar, Sushil |
| Keywords: | 2011
Toxic species
Compartment fires |
| Issue Date: | 19-Dec-2011 |
| Abstract: | Toxic gases and smoke when produced copiously by fire right in initial stage of its development, would lead to fast build up of hazardous conditions for occupants staying inside the compartment of fire origin or in its vicinity. Smoke is easily visible and detectable manually and / or by automatic smoke detection system before reaching dangerous limits. Use of automatic smoke detection and alarm system is wide spread. However, toxic gases when produced copiously during an early stage of fire inside confined space present problem for safety of occupant. Carbon-monoxide (CO) is particularly dangerous because its lethal fatal value (Cf) is as low as 4000 ppm and it is odourless. Occupants remain unaware of its presence. Similarly, increasing concentration of Carbon-dioxide (CO2) coupled with depleting oxygen concentration may produce untenability conditions very fast in confined spaces like sleeping compartments, basements with little openings, long tunnels, long underpasses etc. An automatic system that detects toxic gases and raises alarm, when these gases are present in excess of critical values, is of great help in such scenarios. However, use of automatic toxic gas sensing system is not so common. Work need to be done for development and utilization of such system. New building materials are being introduced in the market that are of non-cellulosic nature and produce high concentrations of toxic gases during burning. Studies on generation and dispersion of toxic gases produced by a variety of building materials while burning become important in this context and are of considerable interest for researchers working in the areas of fire science and materials development.
An experimental study on generation and dispersion of CO/CO2 under flaming and smouldering (pyrolysis) fires was undertaken at Fire Research Laboratory of the Institute. The paper reports the experimental results obtained on generation of these two gases vis-à-vis generation of smoke under flaming and smouldering modes of burning of teak wood sticks. Both types of fires were created in a compartment measuring 7 m (L) x 7 m (W) x 4.2 m (H) with closed door. The gas concentration has been measured in ppm and smoke concentration has been measured in terms of optical density (OD) of the smoke. Peak values and build up rates of CO, CO2 and smoke in flaming and smoulding fires have been recorded. Differences between flaming mode and smouldering mode have been noted for generation of toxic species (CO&CO2) and smoke. It is concluded that though the amount of wood used in flaming mode is 11.6 times more than the amount burned in smouldering mode, still the peak values of Optical Density in smouldering fires are approximately 2.5 times the peak values in flaming fires. It means that, compared to the flaming mode of burning, smouldering mode generates more smoke out of a given mass. Conversion of fuel mass into particulate phase is more in smouldering mode. Generation of CO in smouldering and flaming modes is almost comparable initially but later on it increases in flaming fires. |
| Description: | Proceedings of Fire Science and Technology- Research & Its Implementations- Nov 3-4, 2011, pp 96-104 |
| URI: | http://hdl.handle.net/123456789/646 |
| Appears in Collections: | Published Articles
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