1.1 This test method describes a procedure for estimating the resistance of transparent plastics to one kind of surface abrasion by measurement of its optical effects. 1.2 Abrasive damage is judged by that percentage of transmitted light which, in passing through the abraded track, deviates from the incident beam by forward scattering. For the purpose of this test method, only light flux deviating more than 0.044 rad (2.5°) on the average is considered in this assessment of abrasive damage. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. Note 1-Recent attempts to employ the Taber Abraser for volume loss determinations of various plastics, like earlier ones, have been unsuccessful because of excessively large coefficients of variation attributed to the data. Insufficient agreement among the participating laboratories has rendered the use of volume loss procedure inadvisable as an ASTM test method. Note 2-For determining resistance to abrasion of plastics by measurement of volume loss, reference should be made to Test Methods D1242. Note 3-For determining the resistance to abrasion of organic coatings by weight loss, reference is made to Test Method D4060. This test uses more aggresive CS-10 or CS-17 abrasive wheels. It suffers from poor reproducibility between laboratories when numerical abrasion resistance values are used. Interlaboratory agreement improves significantly when ranking a series of coatings for their abrasion resistance. Note 4-This test method is similar to ISO 3444, and ISO 4586/2. Their technical content is somewhat different. 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 and health practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see 7.1.2.