For glass to be used for most residential or commercial projects it needs to have impact resistance (be a safety glass) and will need to be either toughened, laminated or toughened-laminated curved glass or curved double glazing.
Restrictions on size and shape are applicable, as with most glazed items and panels. The level of these restrictions depend on various factors such as the thickness of glass to be curved, whether it will be toughened or laminated, the radius size, the angle of the curve and whether the curved glass will be cylindrical or non-cylindrical. The maximum size of glass to be curved is 6m x 3m.
It is important to recall a few aspects of circle geometry in measuring the size of a curved glass panel that is wanted.
The distance around the outside of a circle is the circumference. The length of a line drawn completely through a circle is the diameter, while any line extending from the centre of a circle to the circumference is its radius.
The distance around a particular bend is known as its girth or arc. The chord of a bend is the distance from one point of the bend to the other. To measure the depth of the curve, you take half the distance of the chord and measure to the top of the curve.
The maximum angle of curved glass is 90 degrees and with a small radius, sizes can create very tight curvatures and U-bends for more decorative glass aspects. The same applies for curved double glazing.
Multiply-curved glass items are very possible, creating domes and elliptically shaped items i.e. for rooflights.
How it is made
All curved glass units are made in kiln baths where the radius of the curve required is cut on water jets into metal templates, forming the shape of the glass curvature. The flat glass is placed over the metal mould and the kiln is heated very quickly, kiln goes from 1-1000 degrees in 7 minutes. Glass then forms to the space of the curve.
The glass bends will then be toughened or laminated to create a safety glass to enable compliance with all impact resistance requirements. Large unusual shapes can be achieved as the templates are all made bespoke to fit the need and use of each design as well as performance coatings.
It is also possible to combine multiple curved items to create curved double glazing or triple glazed glass unit.