Semi-Frameless Glass Balustrade

Glass Design and Tolerances

Bowing Allowances – Flatness

Very slight distortion or bowing may occur after toughening but is largely controllable. It will vary with substance, size and shape of the glass. Flatness is measured when the glass is standing on edge, a straight edge placed along the length of the panel and a wedge measurement taken at the centre position. It is to be determined by adherence to requirements for substrates in accordance with AS/NZS2208:1996 & AS/NZS 4667:2000.

Nominal Thickness: 8, 10, 12mm

Annealed Float, Heat Strengthened & Toughened Glass: 1mm every 400mm (5mm Maximum)

Visual distortion

The furnacing of glass panels can produce slight corrugated distortion or roller waves. This visual effect is in the form of distortion bands 250–300mm apart. It is more noticeable in tinted and reflective toughened glass. Less visual distortion is evident with a heat strengthened glass.

Quench pattern

During the toughening process, glass goes through a quenching phase where it is rapidly cooled by high velocity blasts of air. This process may result in the occasional appearance of a strain pattern or darkish shadows due to slightly higher levels of compression adjacent to the air nozzles. Typically, the “quench pattern” is only visible when wearing polarised sunglasses or by viewing the glass from the inside at acute angles. The confirmed observation of this optical phenomenon is a positive indicator the glass has been thermally treated and is not considered a defect.