Significance and Use
The useful life of photovoltaic modules may depend on their ability to withstand periodic exposure to high wind forces, cyclic loads induced by specific site conditions or shipment methods, high loads caused by accumulated snow and ice on the module surface, and twisting deflections caused by mounting to non-planar surfaces or structures. The effects on the module may be physical or electrical, or both. Most importantly, the effects may compromise the safety of the module, particularly in high voltage applications, or where the public may be exposed to broken glass or other debris.
These test methods describe procedures for mounting the test specimen, conducting the prescribed mechanical tests, and reporting the effects of the testing.
The mounting and fastening method shall comply with the manufacturer's recommendations as closely as possible. If slots or multiple mounting holes are provided on the module frame for optional mounting point capability, the worst-case mounting positions shall be selected in order to subject the module to the maximum stresses.
If an unframed module is being tested, the module shall be mounted in strict accordance with the manufacturer's instructions using the recommended attachment clips, brackets, fasteners or other hardware, and tightened to the specified torque.
The test specimen is mounted on a test base in a planar manner (unless specified otherwise), simulating a field mounting arrangement in order to ensure that modules are tested in a configuration that is representative of their use in the field.
During the twist test, the module is mounted in a manner simulating a non-planar field mounting where one of the fastening points is displaced to create an intentional twist of 1.2°.
Data obtained during testing may be used to evaluate and compare the effects of the simulated environments on the test specimens. These test methods require analysis of both visible effects and electrical performance effects.
Effects on modules may vary from no changes to significant changes. Some physical changes in the module may be visible even though there are no apparent electrical performance changes. Conversely, electrical performance changes may occur with no visible change in the module.
All conditions of measurement, effects of the test exposure, and any deviations from these test methods must be described in the report so that an assessment of their significance can be made.
If these test methods are being performed as part of a combined sequence with other mechanical or nonmechanical tests, the results of the final electrical test (7.2) and visual inspection (7.3) from one test may be used as the initial electrical test and visual inspection for the next test; duplication of these tests is unnecessary unless so specified.
Some module designs may not use any external metallic components and thus lack a ground point designation by the module manufacturer. In these cases, the ground path continuity test is not applicable.
1.1 These test methods cover procedures for determining the ability of photovoltaic modules to withstand the mechanical loads, stresses and deflections used to simulate, on an accelerated basis, high wind conditions, heavy snow and ice accumulation, and non-planar installation effects.
1.1.1 A static load test to 2400 Pa is used to simulate wind loads on both module surfaces
1.1.2 A static load test to 5400 Pa is used to simulate heavy snow and ice accumulation on the module front surface.
1.1.3 A twist test is used to simulate the non-planar mounting of a photovoltaic module by subjecting it to a twist angle of 1.2°.
1.1.4 A cyclic load test of 10 000 cycles duration and peak loading to 1440 Pa is used to simulate dynamic wind or other flexural loading. Such loading might occur during shipment or after installation at a particular location.
1.2 These test methods define photovoltaic test specimens and mounting methods, and specify parameters that must be recorded and reported.
1.3 Any individual mechanical test may be performed singly, or may be combined into a test sequence with other mechanical or nonmechanical tests, or both. Certain preconditioning test methods such as annealing or light soaking may also be necessary or desirable as a part of such a sequence. However, the determination of such test sequencing and preconditioning is beyond the scope of these test methods.
1.4 These test methods do not establish pass or fail levels. The determination of acceptable or unacceptable results is beyond the scope of these test methods.
1.5 These test methods do not apply to concentrator modules.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 The following precautionary caveat pertains only to the hazards portion, Section 6, and the warning statements, 220.127.116.11 and 18.104.22.168, of these test methods. 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.