ASTM E3325-21

6.1The primary goal of this practice is to extract representative samples from PV modules for TCLP toxicity testing purposes in order to receive unbiased, comparable and repeatable toxicity test results from independent TCLP testing laboratories.

6.2Solar photovoltaic (PV) modules in the United States and the world reaching end-of-life due to failure, underperformance or breakage due to extreme weather have to be recycled or otherwise safely disposed of following the Resource Conservation and Recovery Act (RCRA) regulation [United States, Resource Conservation and Recovery Act. Pub.L. 94580, October 1976]. For end-of-life PV modules, the U.S. Environmental Protection Agency (EPA) Method 1311 (TCLP) is used for waste characterization based on leaching potential under simulated landfill conditions.

6.3Commercial PV modules contain compounds and alloys of various metals (for example, Ag, Al, Cd, Cu, Ga, In, Ni, Pb, Se, Sn, Te, Zn) which are used in semiconductor compounds and electrical contacts.6.4The validity of the toxicity test results heavily depends on the location of extracted samples in the module, specifically within the laminate area, and the particle size of the extracted samples. Therefore, it is critical that the sample extraction procedure be properly designed to avoid biased or otherwise inaccurate toxicity test results.

6.5The development and application of a homogeneous and representative sampling standard will help utilities and manufacturers to limit the number of variables and to obtain repeatable test results.

1.1The purpose of this practice is to describe a representative and repeatable sample preparation methodology to conduct toxicity testing on solar photovoltaic (PV) modules for use with EPA Test Method 1311: Toxicity Characteristic Leaching Procedure (TCLP).

1.2This practice refers to the extraction and preparation of PV module samples by EPA Method 1311, the testing for eight (8) distinct metals mercury (by Method 7470A), arsenic, barium, cadmium, chromium, lead, selenium and silver (by Method 6010C) as well as the analysis and interpretation of the test results on a module level.

1.3This practice applies to only (1) standard crystalline silicon (c-Si) modules, multi and mono-crystalline silicon with aluminum back surface field (Al-BSF) cell technology and (2) cadmium telluride (CdTe) PV modules.

1.4Other and newer PV technologies and module architectures, for example, passivated emitter and rear cell (PERC), interdigitated back contact (IBC), hetero-junction technology (HJT), multiwire, half cut, shingled etc., have not been evaluated with this practice, although the concept and practice can be easily extended and applied to other technologies following the conceptual approach presented in this document.

1.5The sample extraction/removal methodology applied in this practice is the waterjet cutting sampling method. Sample extraction with mechanical cutting has been extensively evaluated but the variability of TCLP test results based on the mechanical cut samples tend to be much higher (30 %) than that of the waterjet cut samples (8 %).1.6Only the laminate area of the PV module is considered for TCLP testing, as other possible module parts, such as aluminum frame, junction box and cables contain recyclable materials that are already well-documented and are not specific to the PV modules.

1.7The material gravimetric density (g/cm³) throughout the laminate area is considered constant.

1.8This practice was developed to be consistent with three fundamental requirements:

1.9The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.10This 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.

1.11This 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.