What thicknesses of sheet glass does this standard cover?

It covers nominal thicknesses of 2.0, 3.0, 4.0, 5.0, 5.5, and 6.0 mm (Table 1).

How is optical distortion and visual defects tested?

Glass is viewed against a matte black screen illuminated by diffused daylight from a distance of 1.5 meters.

What is the allowable dimensional tolerance for the length and width of sheet glass?

The tolerance on specified length and width is ± 2.0 mm.

IS 2835

: 2009

Flat Transparent Sheet Glass

CurrentFrequently UsedSpecificationBIMArchitectural · Doors, Windows and Shutters

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This standard prescribes the requirements and methods of sampling and testing for flat transparent sheet glass used primarily for glazing in doors, windows, and partitions. It covers nominal thicknesses, dimensional tolerances, and limits for optical distortion and visual defects.

Specifies requirements for flat transparent sheet glass for general purpose glazing.

Quick Reference Values

standard nominal thicknesses2.0, 3.0, 4.0, 5.0, 5.5, and 6.0 mm

thickness tolerance up to 3mm± 0.2 mm

thickness tolerance 4mm to 6mm± 0.3 mm

viewing distance for defects1.5 m

tolerance on length and width± 2.0 mm

Practical Notes

Sheet glass is manufactured by a drawing process, so it may have slight inherent optical distortion compared to float glass (IS 14900). Specify float glass if perfect flatness is required.

When ordering, always specify the nominal thickness, size, and the quality grade (e.g., Ordinary, Selected, or Special Selected) based on the application's visual criticality.

Ensure glass is stored vertically in a dry, well-ventilated area to prevent surface degradation or 'glass weathering'.