Glass replacement is a challenging activity. A double glazed unit 2.4m by 3.0m weighs approx. 450Kg and needs to be carefully handled to prevent accidental breakage.

NACW regularly replace large glass units from ground level shop fronts to high-rise buildings. This turns into a complex operation with access to the side of the building often involving suspended cradles from the roof to get the installation crew in place. Separate lifting equipment is used to hoist the glass into position with vacuum lifters and robotically controlled lifters to carefully align and position the glass units. The weather conditions become critical with wind speeds limited to about 12mph and dry weather for the sealants to cure. This is a high risk activity where breaking the replacement glass, and units around it, not to mention harm to the workforce are a real risk. Buildings with flush glass finishes (no pressure plates or caps) have structurally bonded glass which then takes two visits to install. The first to swap over the glass unit and apply the sealants, the second to remove the temporary stitch plates holding it in position and make good the gaskets.