The effect of embedment depth of relief structures on explosive loading

Introduction. Using relief structures to reduce pressure in case of an indoor explosion is widely spread. Moreover, it is legitimized by regulations. However, regulatory documents ignore the well-known fact that the embedment depth of relief structures is equal to or exceeds the value of their thickness. As of the moment when the relief structure begins to move after the disintegration of its bonding from the frame and up to the moment when it leaves the opening, explosion pressure may rise exponentially.

Goal. The goal is to determine the effect of embedment depth of a relief structure on the pressure rise during an indoor explosion at the initial stage of explosion development when the relief structure moves in the opening.

Research methods. The experiment was conducted in a blasting chamber with an opening door where the model of a relief structure was installed.

Results and discussion. The authors found that, if the chamber remained hermetically sealed, the explosion pressure increased proportionally to t3, at least, up to ΔP < 10 kPa. In case of free motion of a relief structure in the opening, the tightness of the system degraded as the explosion developed. As a result, the relief structure left the opening if the pressure value was below that identified as a result of calculations made for conditions of tightness. Nevertheless, an increase in pressure, even in case of poor tightness, followed a change in dimensionless parameter B, which determined the process at this stage of explosion development.

Conclusions. The process is controlled by dimensionless parameter B. The quantitative difference is triggered by the system tightness loss, accompanying the pressure rise, and emergence of the friction force accompanying the attempt to hermetically seal the system. These two circumstances reduce the relative explosion pressure rise, while the relief structure is in motion in the opening if the friction force is taken account of in the course of identifying the value of pressure at which bonding between the relief structure and the building are disrupted.

1. Pilyugin L.P. Forecasting the consequences of internal emergency explosions. Мoscow, Pozhnauka Publ., 2010; 380. (rus).

2. Gorev V.A., Salymova E.Yu. Usage of sandwich-panels as effective easily jettisonable constructions by inside combustions in individual buildings. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2010; 19(2):41-44. (rus).

3. Molkov V.V., Eber R.M., Grigorash A.V., Tamanini F., Dobashi R. Vented gaseous deflagrations: modelling of translating inertial vent covers. Journal of Loss Prevention in the Process Industries. 2003; 16(5):395-402. DOI: 10.1016s0950-4230(03)00066-4

4. Molkov V., Grigorash A., Eber R., Tamanini F., Dobashi R. Vented gaseous deflagrations with inertial vent covers: Stateof-the-art and progress. Process Safety Progress. 2004; 23(1):29-36. DOI: 10.1002/prs.10002

5. Rastorguev B.S., Plotnikov A.I., Khusnutdinov D.Z. Design of buildings and structures under emergency explosive impacts : textbook. Мoscow, Izd-vo ASV, 2007; 152. (rus).

6. Bradly D. Evolution of flame propagation in large diameter explosions. Molkov V.V. (ed.). Proceedings of 2nd International Seminar on Fire-and-Explosion Hazard of Substances and Venting Deflagrations. Moscow, All-Russian Research Institute for Fire Protection, 1997; 51-59.

7. Solberg D.M. Observations of flame instabilities in large scale vented gas explosions. 18-th Symposium (International) the combustion institute. 1980; 1607-1614.

8. Tomin S.V. The explosion can now be counted! Romanov readings : Collection of materials of the XI scientific and practical conference. Moscow, March 21, 2023. D.A. Samoshin (еd.). Moscow, 2023; 91-94. (rus).

9. Volchetskaya E.A., Dunaev A.A., Zhamoydik S.M., Zinkevich G.N., Ivanitskiy A.G. Experimental studies to determine the opening pressure and the change of rotation angle of rotatable easy-to-reset structures during a deflagration explosion of an air-fuel mixture. Journal of Civil Protection. 2023; 7(1):43-53. DOI: 10.33408/2519-237X.2023.7-1.43

10. Bunto O.V., Zhamoydik S.M. Experimental investigations of strength and deformation properties of polymeric materials considered as a translucent filling of easy-to-reset structures. Journal of Civil Protection. 2023; 7(1):32-42. DOI: 10.33408/2519-237X.2023.7-1.32

11. Kirina A.S. Easily throwable structures. An article in the proceedings of the conference. Trends in the development of modern science : Proceedings of the scientific and practical conference of students and postgraduates of Lipetsk State Technical University. Lipetsk, 2023; 457-461. (rus).

12. Potashev D.A. About the danger of gas explosions in closed construction volumes. Vestnik Saint-Petersburg university of State fire service of EMERCOM of Russia. 2023; 2(213-218). (rus).

13. Maksakova A.V. A study of regulatory documentation on the topic of an easily removable structure and a proposal to change it. In the collection: Youth innovations : collection of materials of the seminar of young scientists within the framework of the XXIII International Scientific Conference. Moscow. 2020; 144-147. (rus).

14. Gorev V. Ensuring explosion safety of residential buildings. International Scientific Conference Environmental Science for Construction Industry – ESCI 2018. 2018; 193:03046. DOI: 10.1051/matecconf/201819303046

15. Gorev V.A., Molkov V.V. On the dependence of internal explosion parameters on the installation of safety structures in the apertures of the protecting walls of industrial and residential buildings. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2018; 27(10):6-25. DOI: 10.18322/PVB.2018.27.10.6-25 (rus).

16. Gorev V.A., Korolchenko A.D. The effect of venting structures on overpressure caused by an indoor explosion. Pozharo­vzryvobezopasnost/Fire and Explosion Safety. 2022; 31(3):12-23. DOI: 10.22227/0869-7493.2022.31.03.12-23 (rus).

17. Chen D., Wu C., Li J., Liao K. A numerical study of gas explosion with progressive venting in a utility tunnel. Process Safety and Environmental Protection. 2022; 162:1124-1138. DOI: 10.1016/j.psep.2022.05.009

18. Chmielewski R., Bąk А. Analysis of the safety of residential buildings under gas explosion loads. Journal of Building Engineering. 2021; 43:102815. DOI: 10.1016/j.jobe.2021.102815

19. Gorev V.A., Chelekova E.Yu., Leshchev N.V. On the efficiency of blast relief panels located in the cover. Occupational Safety in Industry. 2023; 5:7-14. DOI: 10.24000/0409-2961-2023-5-7-14 (rus).

20. Polandov Yu.K., Korоlchenko D.A., Evich A.A. Conditions of occurrence of fire in the room with a gas explosion. Experimental data. Pozharovzryvobezopasnost/Fire and Explosion Safety. 2020; 29(1):9-21. DOI: 10.18322/PVB.2020.29.01.9-21 (rus).

21. Strel`chuk N.A., Orlov G.G. Determination of the area of blast structures in buildings of explosive industries. Promyshlennoe stroitel’stvo. 1969; 6:19-22. (rus).

22. Komarov A.A. Forecasting loads from emergency deflagration explosions and assessing the consequences of their impact on buildings and structures : dissertation for the degree of Doctor of Technical Sciences. Moscow, MGSU, 2001; 460. (rus).

23. Gromov N.V. Improvement of the technical system for ensuring explosion resistance of buildings during explosions of gas-steam-air mixtures : dissertation for the degree of candidate of Technical Sciences. Moscow, MGSU, 2007; 134. (rus).