## 1 Introduction  
Currently, there still remains a high risk of emergency situations in the Russian Federation caused by household gas explosions. According to the official statistical data by the Russian Emercom, more than 1000 accidents caused by household gas explosions were registered from 2016 through 2020. Such events are widespread and are triggered by a variety of causes. The causes of cooking-gas explosions in residential neighborhoods are stipulated by a range of interconnected factors (circumstances) of a technical or regulatory nature or involve human factors [1, 2, 3, 4, 5, 6, 7, 8]. Three consequently emerging events appear to constitute the required conditions for an indoor gas explosion: a gas leak from the gas supply system, a gas accumulation up to an explosive concentration, or introduction of an ignition source in a gassy room [9, 10, 11, 12, 13, 14, 15, 16, 17]. A gas leak may generally occur within two scenarios: (a) an emission of a significant amount of gas within a short period of time as a result, for instance, of an emergency depressurization of the supply gas pipe; (b) a slow (with low gas flow) accumulation of gas inside a room from, for example, an unlit or flamed-out burner of a gas cooker [18, 19, 20, 21, 22, 23]. When inflammable substances escape from gas cookers in households or professional equipment at industrial sites, there an explosive and flammable mixture appears [24, 25, 26, 27]. Explosive accidents most frequently take place inside buildings. They entail not a detonation but rather of a deflagration kind of explosion transformation, which defines the specifics of explosion-load prediction methods, as well as consequential mitigation approaches [28; 29; 30; 31]. Excessive pressure in an internal deflagration explosion in an enclosure might be as high as 700...900 kPa, which would result in the destruction of any construction site. However, as demonstrated by publications in the area of blast resistance and explosion safety of buildings under construction, such as those published by Moscow State University of Civil Engineering (MGSU) and National Research University, protective structures (PS), such as panel-window openings and explosion-venting structures (EVS), may significantly reduce explosive pressure to a safe level, in the range of 2-4 kPa [32; 33]. The maximum pressure for premises with glass-panel blast-relief openings (windows) mainly depends on the fracture-initiation pressure. For EVS-equipped premises, the maximum value of explosive pressure depends on the EVS start-to-open pressure, the response time of the structure, and characteristic dimensions of the premises. When flame approaches a blast-relief opening, the density of the outgoing gasses changes abruptly. This generates the first maximum in the pressure-versus-time characteristic. The second pressure surge corresponds to the maximum flame-front area in a steady flow of combustion products through the relief openings. In the presence of explosion-venting structures, there is an additional pressure spike (maximum) in the explosive-pressure time law located before the first pressure surge. Its value depends on the characteristic dimensions of the room, the EVS response rate (lag), and the size of the opening. In some cases, for example, for small volumes, the EVS-triggered maximum pressure and the first pressure surge may merge, which makes analysis of experimental data more difficult. Figure 1 illustrates how the first pressure surge gets absorbed by the EVS-triggered maximum pressure, showing experimental waveforms (oscilloscope pressure patterns) of explosive pressure in a room with an uncovered opening and an EVS-equipped opening. Figure 1: Experimental waveforms for an explosion of a propane-air mixture in a cubic chamber (\(h=305\) mm): (**a**) uncovered openings; (**b,c**) openings covered with EVS-simulating panels.