NS is Normal Strength and relates to a 0.38mm PVB interlayer. HPR is High Penetration Resistance and relates to a PVB thickness of 0.76mm. HI is High Impact and relates to a PVB interlayer of 1.52mm. NS and HPR comply to the requirements of SABS 1263 part 1, whilst HI also complies with part 2. The thickness of ordinary float and rolled glass is normally described as the nearest whole number within the thickness variation.
Laminated glass is more complicated due to the thickness of the interlayer.
PFG uses the internationally accepted method of describing laminated glass. The laminate is made from two or more pieces of glass. A standard PVB has a thickness of 0.38mm. Also available are 0.76mm, 1.14mm, and 1.52-mm. The thickness of a laminate made of two 3mm glasses and a 0.38mm vinyl is therefore 6.38mm.