A pane of glass is oversized to the space it’s required to fill. In some cases, the glazing channel that houses the glass has a removable bead to all sides to allow the glass to be inserted. The bead is then clipped in to hold the glass in place.
In most situations, the bottom has a removable bead with fixed channels top and two sides. If there is only one pane of glass, this would require the glazier to ‘shuffle’ glaze – slide the glass to the back of one glazing pocket and shuffle the glass in the opposite direction, into the centre point of the alternate pocket.
As the demand for higher rated acoustic glazed partitions increases, it is important that ‘Edge Cover’ and ‘Edge Clearance’ are considered in order for the glazing to be installed as per the New Zealand Glazing Code.
If edge cover and edge clearance are considered at the initial design stage, it can avoid issues with remedial costs, or unwanted silicon butt joints in the glazing.
12mm glass requires a minimum of 6mm edge clearance – 6mm from the edge of the glass to the edge of the pocket. 12mm glass also needs 9mm edge cover – 9mm from the edge of the glass to the back of the glazing pocket.
This will mean, 12mm glass will require that the pocket depth on one side be a minimum of 18mm deep i.e. slide the glass in 18mm, shuffle back 9mm. This would give 9mm edge cover and 9mm edge clearance on both sides.
Why is this important?
Majority of fixed glazing channel has a pocket depth of 16mm, making it impossible to shuffle glaze one pane of glass and meet the glazing code.
Where there is only one pane of glass, we recommend designing one of the fixed glazing pockets to be greater than 18mm deep.
Single Glazing vs Multi Pane Glazing
With multi pane glazing there are no issues with edge cover or edge clearance. This is due to the difference in installation of the panes of glass versus a single glaze.
The main difference in the installation is the glazing that is installed into the partition pockets can be installed first, using the first depth – removing one step in the shuffle glaze system.