Novel hybrid vacuum/triple glazing units with pressure equalisation design

Vacuum glazing units (VGUs) are thought to be a type of glazing system with superior effective insulation performance. However, the differential pressure between the outside and the inner spaces and the supporting pillars create a high pre-existing stress field in the constituent glass during fabrication and hence make the units highly susceptible to breakage, even under small applied loads. In order to address this problem, a novel hybrid vacuum/triple glazing system with a pressure equalisation design has been devised and is reported in this paper. In this system, a VGU is enclosed by two glass panels to form a triple glazing unit system. This new design creates an equalised air pressure on both sides of the VGU hence subjects the VGU to no additional loads apart from the inherent fabrication stresses. This results in a high thermal and sound insulation as well as a more durable safety performance of the hybrid glazing component. Pressure tests were undertaken on the novel glazing system to confirm its reliability. Results show that under various loading levels, the stresses and deflections in the VGU of this novel glazing system always remain at a marginal level, and hence the likelihood of breakage for VGUs can be reduced significantly.