Vacuum Insulation Glass: Prerequisites
The design of vacuum insulation glass (VIG) is similar to conventional double glazing, only the gap between the panes is evacuated and there are supports fixed between the panes at regular intervals to take up the surrounding pressure (cf. Assembly). Compared with conventional insulation glazing systems, the only special prerequisite is to avoid thermal bridges in the area of the edge seal. Another matter about VIG that often leads to misunderstandings is the case of pane breakage. Both points are clarified below:Pane breakage: VIG principally has the same mechanical load capacity as conventional insulation glass. If a pane breaks nevertheless (e.g. due to external force), there is no danger of exploding glass even if no safety glass is used as the vacuum between the panes would actually cause the glass to implode.
Thermal bridges: Due to the excellent insulating value in the middle of the panes (Ug ≈ 0.5 W/(m²K), thermal bridges in the area of the edge seal are particularly noticable. When installing VIG, therefore, a highly-insulating frame construction should always be implented (cf. Edge effects). Highly-insulating frames are currently being developed within the framework of a project funded by the German Federal Ministry of Economics and Technology.
