Standard Active Last Updated: Nov 16, 2021
ASTM C1652/C1652M-21

Standard Test Method for Measuring Optical Distortion in Flat Glass Products Using Digital Photography of Grids

Significance and Use

5.1 This test method provides accurate data for evaluation of the optical properties of the glass being inspected.

5.2 The procedure described is useful for observing the roll wave introduced during the tempering process of flat architectural glass. (1)

5.3 This test method is also useful for inspection of laminated and tempered automotive glass in transmitted light, in both flat and curved geometries.


1.1 This test method covers the determination of optical distortion of heat-strengthened and fully tempered architectural glass substrates which have been processed in a heat controlled continuous or oscillating conveyance oven. See Specifications C1036 and C1048 for discussion of the characteristics of glass so processed. In this test method the reflected image of processed glass is photographed and the photographic image analyzed to quantify the distortion due to surface waviness. The test method is also useful to quantify optical distortion observed in transmitted light in laminated glass assemblies.

1.2 The values stated in either SI units or inch-pound units are regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

1.3 There is no known ISO equivalent to this test method.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Book of Standards Volume: 15.02
Developed by Subcommittee: C14.11
Pages: 7
DOI: 10.1520/C1652_C1652M-21
ICS Code: 81.040.20