Double glazed units that are transported or installed at high altitudes, i.e. above 600 metres above sea level, must be fitted with tempered glass and pressure valves (bi-directional pressure valves – Fig. 1, Pressure Stabilization System SWS AIR – Fig. 2), as otherwise the glass units may break, sealant zones may be sealed, and large glass units may collapse.

Fig. 1 Bidirectional pressure valve

Fig. 2 SWS AIR system