Areas that one can look to when considering the quality of a panel of curved glass.
Optically it should have no waves in it which give a distorted view when looking through the glass. However because it is produced by means of a heat process, small surface blemishes are unavoidable and inspection from a distance of 3mtr is the standard set and used by the industry.
Accuracy of the curve is vital in most cases to ensure that the glass fits without being put under pressure. Where a particular job is difficult, we would normally alert the customer beforehand that the normal tolerances cannot be guaranteed and that a little extra manoeuvrability should be built in. Included in the area of accuracy is the need for straightness (no warping) in the vertical height of the curved panel.
(This is not a problem with annealed laminated panels, but we usually warn customers that in the case of toughened panels allowance needs to be made for warping / bowing in the vertical height of panels over1.5 – 2 mt high).