A new approach to calculating the time to the blocking of the escape routes due to the loss of visibility in the smoke of an indoor fire

Introduction. The accuracy of the visibility analysis in the event of an indoor fire strongly depends on the smoke-generating ability of substances and materials obtained experimentally in small-scale units. Therefore, the task is to develop a method of analysis that takes account of the scale factor and does not use the specific coefficient of smoke generation to identify the range of visibility in a full-scale room.
Goals and objectives. The goal of the research project is a new approach to the calculation of the time to the blocking of the escape routes due to the loss of visibility with due regard for the scale factor and without regard for the specific coefficient of smoke generation. To achieve this goal, the analysis of fire development patterns in small-scale and full-scale rooms was carried out; theoretical dependences between the volumetric average optical smoke density and other volumetric average parameters of the indoor gas environment were obtained for these patterns, and calculation results, based on the obtained dependences, were compared with the experimental data.
Methods. Methods, employed by the co-authors, included solving non-stationary equations based on the principle of conservation of indoor gas energy, optical density of smoke and oxygen mass for the cases of closed and open-type indoor heat and mass transfer. Fire tests were conducted in a small-scale facility. Theoretical and experimental data were compared.
Results. Analytical dependences between the volumetric average optical density of smoke, a change in the volumetric average temperature, and the volumetric average partial oxygen density for closed and open indoor fire patterns were obtained. The series of fire tests involving the PVC insulated and sheathed bare (coverless) cable, exposed to the effect of the varying density incident heat flux, were carried out. Experimental dependences between the time, the optical density of smoke, and the specific coefficient of smoke generation were obtained. The obtained volumetric average optical density of smoke was compared with the experimental data using the proposed analytical expressions.
Conclusions. The co-authors suggest using experimental dependences between the volumetric average optical density of smoke, changes in the volumetric average temperature or the volumetric average partial oxygen density obtained in a small-scale facility without solving the differential equation based on the principle of conservation of optical density of smoke.

1. Aleksandrenko M.V., Akulova M.V., Ibragimov A.M. Mathematical modelling of the fire. Meždunarodnyj naučno-issledovatel’skij žurnal /International research journal. 2015; 4-1(35):28-29. URL: https://research-journal.org/technical/matematicheskoe-modelirovanie-pozhara/ (rus).

2. Yarosh A.S., Chalatashvili M.N., Krol A.N., Popova E.A., Romanova V.V., Sachkov A.V. The system of buildings and structures dangerous fire factors development mathematical models alysis. Bulletin of research center for safety in coal industry/Industrial safety. 2019; 1:50-56. (rus).

3. Dennai B., El M., Khelfaoul R. Numerical investigation of flow dynamic in mini-channel: case of a mini diode Tesla. Fluid Dynamics & Materials Processing. 2016; 12(3):102-110. DOI: 10.3970/fdmp.2016.012.102

4. Du J., Wu X., Li R., Cheng R. Numerical simulation and optimization of a mid-temperature heat pipe exchanger. Fluid Dynamics & Materials Processing. 2019; 15(1):77-87. DOI: 10.32604/fdmp.2019.05949

5. Ihdene M., Malek T.B., Aberkane S., Mouderes M., Spiterri P., Abderrahmane G. Analytical and numerical study of the evaporation on mixed convection in a vertical rectangular cavity. Fluid Dynamics & Materials Processing. 2017; 13(2):85-105. DOI: 10.3970/fdmp.2017.013.235

6. Ja A., Cheddadi A. Numerical simulation of thermosolutal convective transitions in a very narrow porous annulus under the influence of Lewis Number. Fluid Dynamics & Materials Processing. 2017; 13(4):235-249. DOI: 10.3970/fdmp.2017.013.235

7. Triveni M.K., Panua R. Numerical study of natural convection in a right triangular enclosure with sinusoidal hot wall and different configurations of cold walls. Fluid Dynamics & Materials Processing. 2018; 14(1):1-21. DOI: 10.3970/fdmp.2018.014.001

8. Koshmarov Yu.A. Forecasting of fire hazards in the case of indoor fire. Moscow, State Fire Academy of Emercom of Russia Publ., 2000; 118. (rus).

9. Kolodyazhny S.A., Pereslavtseva I.I. Mathematical modeling of the dynamics of the main hazards in the initial stage of fire. News of the Kazan State University of Architecture and Engineering. 2014; 4(30):403-412. URL: https://elibrary.ru/item.asp?id=23419307 (rus).

10. Husted B.P., Carlsson J., Goransonn U. Visibility through Inhomogeneous smoke using CFD Proceedings of Interflam. Edinburgh, 2004; 697-702.

11. Drayzdel D.D. An introduction to fire dynamics. Chichester, John Wiley and Sons, 1985.

12. Mustafin V.M., Puzach S.V. The effect of primary illumination and smoke-forming ability on the estimated time of blocking escape routes because of poor visibility. Bezopasnostʼ zhiznedeyatelʼnosti/ Life Safety. 2020; 2:17-22. (rus).

13. Orzel R.A. Toxicological aspects of firesmoke: polymer pyrolysis and combustion. Occupational Medicine. 1993; 8(3):414-429.

14. Puzach S.V., Smagin A.V., Lebedchenko O.S., Abakumov E.S. New ideas about the calculation of necessary time of evacuation of people and the effectiveness of using a portable filter self-rescuers during evacuation at fires. Moscow, State Fire Academy of Emercom of Russia Publ., 2007; 222. (rus).

15. Mustafin V.M., Puzach S.V., Akperov R.G. Influence of conditions in the combustion chamber of small-scale installation on smoke generating ability of wood. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2020; 29(1):23-31. DOI: 10.18322/PVB.2020.29.01.23-31 (rus).

16. Rasbash D.J., Drysdale D.D. Fundamentals of smoke production. Fire Safety Journal. 1982; 5(1):77-86.

17. Barbotko S.L., Volnyy O.S. Heat release assessment at burning electric cables. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2016; 25(11):35-44. DOI: 10.18322/PVB.2016.25.11.35-44 (rus).

18. Puzach S.V. Methods for calculating the heat and mass exchange in a fire in the room and their application in solving practical tasks of fire and explosion protection. Moscow, State Fire Academy of Emercom of Russia Publ., 2005; 336. (rus).

19. Mouritz A.P., Gibson A.G. Fire properties of polymer composite materials. Dordrecht, Netherlands, Springer, 2006; 398. (rus).

20. Widmann J.F. Evaluation of the planck mean absorption coefficients for radiation transport through smoke. Combustion Science and Technology. 2003; 175:2299-2308. DOI: 10.1080/714923279 (rus).

21. Puzach S.V., Suleykin E.V. New united theoretical and experimental approach to the calculation of the distribution of toxic gases in case of fire in the room. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2016; 25(2):13-20. DOI: 10.18322/PVB.2016.25.02.13-20 (rus).

22. Puzach S.V., Akperov R.G. Experimental determination of the specific coefficient of release of carbon monoxide during a fire in the room. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2016; 25(5):18-25. DOI: 10.18322/PVB.2016.25.05.18-25 (rus).