## 2 Experimental Setup and Experimental Procedure
### Numerical Experiment  
In order to determine the dynamics of excessive pressure inside an EVS-equipped room, the following common differential equation should be solved [34]:  
\[\frac{dP}{dt}=\frac{\alpha\cdot S(t)\cdot(\varepsilon-1)\cdot U_{n}-\mu\cdot \sqrt{\frac{2\Delta P}{P_{j}}}\cdot S_{op}\cdot f(t)}{\frac{V_{1}}{\gamma_{1}}+ \frac{V_{2}}{\gamma_{2}}}\cdot P(t), \tag{3}\]  
where \(P(t)\) is the current pressure value; \(\Delta P\) is excessive pressure; \(S(t)\) is the current value of the flame-front surface area; \(S_{op}\) is the overall area of relief openings; \(\rho_{j}\) is the density of the cold mixture (\(\rho_{1}\)) or combustion products (\(\rho_{2}\)); \(\varepsilon\) is the degree of mixture expansion; \(\gamma_{j}\) is the specific heat ratio of the fresh mixture (\(\gamma_{1}\)) or combustion products (\(\gamma_{2}\)); \(U_{n}\) is the normal flame-propagation rate; \(V_{j}\) is the current volume of fresh mixture (\(V_{1}\)) or combustion products (\(V_{2}\)); \(\alpha\) is the combustion-intensification coefficient; \(\mu\) is the flow-rate coefficient for the gases that escape through the relief opening; \(f(t)=S_{op}^{\text{CLR}}(t)/S_{op}\) is the functional relationship between the residual obstruction of the relief openings and the protective structures; and \(S_{op}^{\text{CLR}}(t)\) is the current value of the relief-opening areas that are clear of protective structures.  
For premises equipped with blowout EVS, the functional relationship between the residual obstruction of the relief opening and the EVS can be presented in the following form:  
\[f(t)=\left\{\begin{array}{ll}0,&\text{if }\Delta P<\Delta P_{op};\\ \frac{x(t)\cdot N_{\text{EVS}}}{S_{1 op}},&\text{if }x(t)<\frac{S_{1 op}}{N_{ \text{EVS}}};\\ 1,&\text{if }x(t)>\frac{S_{1 op}}{N_{\text{EVS}}},\end{array}\right. \tag{4}\]  
where \(S_{1 op}\) is a single opening area, \(N_{\text{EVS}}\) is the single EVS perimeter, \(x(t)\) is the EVS shift, and \(\Delta P_{op}\) is the excessive pressure when opening of the venting panel occurs.  
For turning structures, the functional relationship between the residual obstruction of the relief opening and the EVS will be somewhat different from that in (4).  
It can be deduced form (4) that in order to determine \(f(t)\), we need to know the EVS shift-versus-time characteristic, \(x(t)\). For this to be determined, Equation (3) should be supplemented with two common simultaneous differential equations:  
\[\left\{\begin{array}{ll}\frac{dx(t)}{dt}=V(t),\\ \frac{dV(t)}{dt}=\frac{g\cdot(\Delta P-K\cdot\Delta P_{op})}{\Delta P_{rep}}, \end{array}\right. \tag{5}\]  
where \(V(t)\) is the EVS shift velocity; \(\Delta P_{resp}=\frac{m\cdot\delta}{S_{1 op}}\) is the structure-responsiveness parameter; \(K\) is the EVS location parameter (\(K=1\) when EVS is located on the roof of the building, \(K=0\) when EVS is located on the walls of the building); \(\delta\) is the acceleration of gravity; and \(m\) is the mass of a single venting structure.  
The simultaneous Equations (3) and (5) need to be solved with regard to the following initial conditions:  
\[\left\{\begin{array}{ll}\Delta P=0,&\text{if }t=0;\\ x(t)=0,&\text{if }\Delta P<\Delta P_{op};\\ V(t)=0,&\text{if }\Delta P<\Delta P_{op},\end{array}\right. \tag{6}\]  
where \(\Delta P_{op}\) is the EVS panel start-to-open pressure.  
When solved, the simultaneous equations provide the required excessive pressure inside the EVS-equipped premises.  
The calculation results conducted according to the above-mentioned method and the followup discussion will be presented following analysis of experimental data obtained at the full-scale test site.