Influence of Pressure Equalisation Elements on the Quality of Insulating Glass Units

Continuous increase of expectations concerning improvement in quality of building partitions by means of increasing their thermal insulation properties brings, among others, a need of modification in standards that have been applied to the double glazed windows so far. Triple-glazed and quadruple-glazed IGUs are used more and more often. Such elements have better thermal properties, but they are more prone to deflection and stress resulting from climatic load, i.e. changes in temperature, atmospheric pressure and wind load. Due to the above certain concepts occurred that consist in equalising gas pressure in the gas-filled gaps with the atmospheric pressure. The article contains assessment of such solutions in the context of providing suitable technical parameters of glass panes: thermal insulation and susceptibility to climatic load. It was stated that the pressure-equalizing elements (capillaries) can result in a significant reduction in the quality of the glass partition in the event of the argon purging chamber or damage to the low-E emissions. The lower risk of using required thermal properties occurs when periodically active valves are used, they operate only in case of extreme pressure level differences. Further analysis concerned the idea of pressure equalisation between the gaps of a triple-glazed unit, as that can be done by using an edge spacer of appropriate design. On the basis of comparative analysis of static values it was shown that it is a reasonable solution. Such a unit maintains the properties of a tight unit, while the possibility of gas exchange between the gaps leads to relief of the central glass pane in the unit, thus allowing for decreasing its thickness to 2 mm.