prEN IEC 62788-7-3:2021

This standard defines the test methods that can be used for evaluating the abrasive durability of materials and coatings in photovoltaic modules or other solar devices. The standard was developed to address components on the irradiance incident surface (including coatings, frontsheet, and glass) as well as back surfaces (including backsheets or back glass). This standard is intended to address abrasion of PV materials and components using representative "coupon" specimens (e.g. which can be centimetres in size); some methods and apparati used here can also be used on PV module specimens (e.g. meters in size). The test methods are intended to imitate damage mechanisms that can occur due to terrestrial use or occurring during the cleaning of photovoltaic modules. A suite of tests and their methods are identified in this standard, including falling sand, forced sand impingement, and machine (brush) abrasion. The methods are intended apply to the front-surface and back-surface of PV modules, and can have test levels specific the test surface of interest. Materials and coatings can have different intended design purposes and design lifetimes and therefore no specific pass/fail criteria are defined in this standard. The results of the testing can, however, be used to identify relative durability of coatings for various outdoor environments and cleaning practices. The methods can be used for the purpose of relative comparison, e.g. for the purpose of material or coating selection. The quantitative correlation between artificial abrasion and field erosion (which will depend on factors including climate or location of use as well as application, e.g., utility installation, residential-installation, roof-mount, rack-mount, use of a tracker, the system electrical configuration and its operation, vehicle integrated PV) can be established for each specific material or coating, which is beyond the scope of this document. The methods related to the characterization of abraded specimens (which might include optical transmittance, optical reflectance, surface roughness, and surface energy) are not defined in this standard; characterization methods from other standards (including optical transmittance, optical reflectance, electrical performance, surface roughness, and surface energy) can be applied to specimens abraded using the methods defined in this standard. Methods for examining the contamination of specimens, including artificial soiling, are not examined in this standard. Additional specimen conditioning can be applied prior to the methods in this standard. The abrasion tests in this standard can be referenced and/or applied in conjunction with an accelerated test or test sequence in other standards.