## 3 Results  
The theoretical correlations provided earlier, in combination with the experiment results, demonstrate that the maximum explosion pressure in EVS-equipped premises depend on various parameters related to the venting structure (its dimensions and specific weight), as well as flammable-mixture properties and room dimensions. Minor structural features of the EVS allow us to narrow the maximum explosive-pressure values to one EVS parameter--the initial panel-opening pressure, \(P_{op}\). To achieve this, the EVS or enclosing structures of the premises should be designed to have relatively small openings covered with crushable membranes, for instance, common glass or small-sized blowout panels. The only requirement for those additional openings is that they should be shed (\(P_{shd}\)) at pressure values a little higher than the main EVS panel-opening pressure (\(P_{shd}>P_{op}\)), while the opening area should constitute 10% or more of the overall EVS area. This very upgrade of the EVS allows for the provision of maximum explosive loads corresponding to the membrane-destruction pressure on additional relief openings or the shedding pressure (\(P_{shd}\)). To illustrate the efficiency of an upgraded EVS, Figure 9 provides the calculation results of explosive pressure inside a kitchen. The premises under consideration had the following dimensions: 2.75 \(\times\) 3.0 \(\times\) 4.0 m, with a 1.5 \(\times\) 2.0 m window opening, a hinged EVS with a response rate of 0.5 kPa (50 \(\mathrm{kG}\)/\(\mathrm{m}^{2}\)) and an opening pressure of \(P_{op}\) = 2 kPa. The additional opening in the EVS opens when pressure reaches \(P_{shd}\) = 2.5 kPa. Calculations were conducted for a non-upgraded EVS and for EVSs with an additional 0.1 m\({}^{2}\) (3.34% of the EVS surface area), 0.25 m\({}^{2}\) (8.35% of the EVS surface area), and 0.5 m\({}^{2}\) (16.7% of the EVS surface area) opening. Figure 9 provides calculations of explosive pressure with a fully open window area (curve 1). The operational principle of the suggested EVS upgrade is as follows. With no additional opening equipped with a crushable or shedable membrane, pressure inside the room increases in the following way. First, explosion pressure increases in an enclosed space. When the pressure reaches the EVS opening value, \(P_{op}\), arresting devices break, and the EVS starts to shift. Explosion pressure increases further as flame-front area increases  
Figure 9: Excessive pressure of an explosion inside a kitchen: (**A**) non-upgraded EVS; (**B**) EVS with an additional 0.1 m\({}^{2}\) opening; (**C**) EVS with a 0.25 m\({}^{2}\) opening; (**D**) EVS with a 0.5 m\({}^{2}\) opening; 1— explosive pressure inside the kitchen with a fully open window area. and, correspondingly, the inflow of combustion products increases. Their withdrawal at this stage is insignificant because the EVS shift is minimal, and the shed window is only a slightly open. As the EVS gets shifted further, the area of the opening increases, and at a certain point, the inflow of combustion products is fully compensated for by the discharge of gases through the opening window. That is the moment when the pressure caused by the presence of the EVS reaches its maximum. Further shifting of the structure increases the opening area and leads to a pressure decrease. When the opening is clear of the EVS, the explosive-pressure time law is identical to the pressure time law in a non-EVS-equipped room (see Figure 9). When an additional opening is used with a crushable or an easy-to-open element, which can be achieved by decreasing the dimensions of sheddable elements (increasing the division of EVS elements covering the additional opening), the pressure increase develops in the following way. Similarly to the previous case, first, explosion pressure increases in an enclosed space. Then, when the pressure reaches the EVS opening value, \(P_{op}\), the arresting devices break, and the EVS starts to shift. At this point (or a bit later), elements covering the additional opening are shed.