【国外标准】 Standard Practice for Short Term Vehicle Service Exposure of Automotive Coatings

4.1 Since the exposure of automotive coatings to the various mechanical and chemical stresses encountered in actual operations, is very opportunistic, obtaining statistically significant data from which valid conclusions can be drawn, requires rigorous attention to the experimental designs and conditions of exposure.1.1 This practice covers the protocol for vehicle service exposure testing of automotive coatings. Such exposure testing is valuable for the verification of the performance of automotive coatings and correlation with laboratory test data. Vehicle service exposure is intended to provide short term (2 to 20 weeks) exposure to the stress factors associated with vehicle operation. Factors included are scratch, mar, impact, stone chipping, insect impact, bird dropping, tree sap and staining, environmental fallout, etc.NOTE 1: Vehicle service exposure is not intended to provide the conditions that are needed for characterizing the long term effects of weathering or corrosion exposure.1.2 The exposure conditions are produced by the placement of multiple test panels of automotive finishes on automotive test fleets that traverse a defined road course. Exposure to the operating environment can be 20 h/day, 7 days/week allowing for accumulation of over 100 000 miles in 10 weeks of exposure.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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.