Several organisms, such as the International Electrotechnical Commission (IEC), the Institute of Electrical and Electronic Engineers (IEEE), have designed tests aimed at guaranteeing the quality of PV products . Test procedures have been defined that, if successfully passed by a product, should guarantee the reliability of the PV module.
Manufacturers voluntarily submit their products to qualification tests in an accredited laboratory. These include verification of the module performance claimed in the datasheets as well as reliability tests. The certifications obtained are intended as a quality assurance for the customer.
Qualification tests consist in verifying the module integrity by visual inspection, measurement of the electrical performance at STC and of the electrical isolation before and after treatments that simulate, in an accelerated manner, real operation conditions. For instance, the IEC Standard 61215  specifies:
• Ultraviolet exposure using xenon lamps.
• Thermal cycling (-40 °C to 50 °C, 50 cycles) in climate chamber.
• Humidity freeze cycling (thermal cycling with 85% relative humidity).
• Damp heat (1000 hours at 85 °C and 90% relative humidity).
• Twist test for testing resistance to torques.
• Pressure is applied to the module to test resistance to static mechanical loads.
• Hail impact test, where the module is struck by 25-mm-diameter ice balls at a speed of 23m/s.
• Outdoor exposure.
• Hot spot tests, where the module is selectively shaded.
Different test combinations are applied to a sample of a few modules. The modules will qualify if no major failures are found, the visual inspection reveals no damage, the electrical power is within 90% of specifications, and isolation is maintained.