## 1 Introduction
[PERSON] et al. [19] numerically investigated triple glass units to assess their performance under explosive loading. Circular and elliptical IGUs were investigated numerically in [9]. In the article [20], the influence of large deflections on the load distribution and the possible reduction of the thickness of glass used in IGUs on cruise ships was investigated numerically. In engineering practice, software for the structural design of IGUs has been developed [21; 22]. However, their functionality is limited, particularly regarding the number of gaps and geometrical features. The increased interest in the issues mentioned above occurred after the popularization of the use of triple-glazed units. Currently, due to the need to save energy, the use of even 6-pane IGUs [23] is being considered. In article [24], based on detailed calculations, it was shown that increasing the total thickness of the gas gaps increases, approximately linearly, the maximum stress and deflection in the IGU loaded with a change in atmospheric pressure. Increased stress should also be expected in the case of curved IGUs, which is related to the low susceptibility of such glass to deflection. This issue is important because in certain conditions, in particular together with mechanical loads, it may lead to glass cracking [25; 26]. Therefore, there is a demand for introducing pressure-equalizing mechanisms to the IGU structure [27; 28; 29]. However, this solution is limited due to technical issues and limitations introduced by product standards [30]. Experimental studies are necessary to validate analytical and numerical models. [PERSON] et al. [31] investigated the deflection in IGUs under operating conditions in vari ous locations in the USA using laser devices. [PERSON] et al. [32] measured a window model's heat flow and deflection in a climatic chamber. [PERSON] et al. [33] investigated the load sharing in IGUs triple glazing by controlled pressure change on both sides of the sample. [PERSON] et al. [5] measured pressure changes in gaps by subjecting IGU samples to cyclic temperature changes in a climatic chamber. His main conclusion related to the changes in the connection stiffness of the glass pane with the spacer that depends on the temperature and the number of load cycles. [PERSON]'s work used a numerical model based on FEM for the analysis. [PERSON] and [PERSON] carried out laboratory tests and numerical modeling of the edge connection efficiency investigating different types of spacers for IGUs [17; 18]. The studies on curved IGUs using the cold-bending technique are reported in [34]. In the article [6], [PERSON] used artificially induced over-pressure in the gap to simulate the climatic load, and measured the deflection in the IGU mounted in a window frame. The article [35] describes a similar concept in more detail. It has been proposed that natural changes in atmospheric pressure or temperature can be simulated with an equivalent load resulting from a defined change in gas pressure in the gap. This way, the pressure difference in the gap can be achieved by introducing or removing a certain gas mass into/from the gap. The research methodology used in the current study is based on these ideas, but the structure of the test stand is improved compared to [35]. Instead of a massive metal frame, the tested model was placed between OSB boards, which simplified the test even more. Moreover, during the tests, the response of the glass panes, in terms of the stress in the glass, deflection, and pressure inside the gap, was continuously monitored. This article aims to experimentally determine the resulting pressure difference in the IGU gap, the deflection of the panes, and stress in the glass in an IGU model subjected to loading. The study simulates climatic loads that involve controlled injection/extraction of a certain volume of air into/from the gap. In this way, this method eliminates the need to use a climatic chamber. The article compares the results of experimental research with the analytical and numerical models.