Controlled pressure compensation
If there is a substantial difference in altitude between the production and installation locations, a pressure imbalance can occur, for example when IGUs are delivered to alpine regions. This may subject the glass to bending tensile stresses and place the edge bond under tension or compression. To avoid such tensions, the so-called barometric air pressure can be adjusted directly during production at the installation site. Alternatively, special compensation elements can be used – such as capillaries or valves equipped with integrated special membranes. These components allow pressure equalisation without causing an uncontrolled rise in humidity within the cavity. Excess moisture absorption can overwhelm the desiccant contained in the spacer – which may result in condensation forming on the cold exterior pane.