Building Roofs and Integrated Solar Systems: TÜV Rheinland Commissions New Rain Test Stand

TÜV Rheinland has once again expanded its range of tests for the solar industry. At its laboratory center in Cologne, the world’s leading provider of quality and safety services in the solar industry has commissioned a new test stand to determine the resistance of roof-integrated photovoltaic systems (BIPV) to wind-driven rain. In addition to building-integrated photovoltaic systems, the new test stand will be used to test the resistance of integrated solar thermal systems as well as various types of roof materials to driving rain.

During these wind-driven rain tests, drops of water falling vertically will be directed onto different parts of the building at a certain contact angle under the influence of wind in order to determine the impermeability of the building elements. “Upon completion of our analyses, manufacturers will receive a precise report telling them when, and to what extent, rain started to penetrate the components. As such, we are bridging an important gap in the further development of roof-integrated solar systems and quality assurance for consumers,” states Florian Reil, Head of Solar Energy at TÜV Rheinland in charge of research and innovation. He explains that proof of rain resistance is also required in order for photovoltaic assembly systems to qualify under 2 PfG 1794/10.10. Corresponding evidence is as well mandatory for assembly systems for photovoltaic systems built on sloping roofs in countries such as France and the United Kingdom (MCS 012).

The tests and analyses performed at TÜV Rheinland focus on the system’s resistance to water penetration at different installation angles. Two current European draft standards in particular serve as a basis for these test programs: prEN 15601 in relation to testing of the impermeability of roof elements and prEN 50583 in relation to building-integrated photovoltaic modules. For the test, a roof structure is selected whereby the BIPV system is subjected to both falling rain and running water, with simulated wind and wetting, to test its resistance to moisture.

The various individual tests are performed at roof angles of 15, 30 and 45 degrees. In accordance with prEN 15601, the wind speed is adjusted in increments from 0 to 25 meters per second and rainfall from 6 to 416 millimeters per second. A test series is based on sub-tests of the simulated weather parameters of rainfall, wind speed and running water combined with the various test angles: At low wind speed with a high – and then very high – rate of rainfall, at high wind speed with low rainfall, and with torrential rain but no wind. Detailed assessments of the resistance of the tested systems can then be made upon completion of the twelve sub-tests. By from the definition of prEN 15601, a vacuum is created behind the test area. In addition to these tests, experts in Cologne also perform water spray tests required in accordance with the US standard for photovoltaic modules UL 1703.

On the new test stand developed and built by PSE in accordance with TÜV Rheinland’s requirements, modules are installed on a roof according to the installation instructions using the conventional assembly system. Test specimens of up to 15 m2 are used. Measurements are taken within an effective test area of at least 1 m2, which must contain at least one horizontal and one vertical assembly joint.

“Investors naturally expect roof-integrated modules to withstand rain. However, it’s hard to provide evidence of what this means in practice. Now we can give a precise answer to the question: How much water will penetrate the system under different extreme weather conditions? This is very important for module and system manufacturers. As such, all customers can gain greater trust in this technology as a roofing alternative,” explains Reil. TÜV Rheinland presented in November 2012 a further test program that provides a realistic simulation of the strain placed on photovoltaic systems on sloping roofs by inhomogeneous snow loads. Since then, the company has given manufacturers the opportunity to test their modules – in particular the glass and frame elements – and mounting systems on a new test stand at its laboratory in Cologne to examine how they respond to these specific loads.

As an internationally leading testing service provider for the solar industry, TÜV Rheinland is active in numerous fields of research and innovation for the use of solar energy. The company first started laboratory-scale technical testing of solar components back in 1985. TÜV Rheinland’s network of experts for the solar industry now comprises almost 300 specialists in eight laboratories worldwide. As a global market leader for the testing and certification of solar systems, TÜV Rheinland operates test laboratories in Bangalore (India), Gyeongsan (Korea), Cologne (Germany), Osaka and Yokohama (Japan), Shanghai (China), Taichung (Taiwan) and Tempe (USA). Across the world, well over 500 manufacturers of photovoltaic products are customers of the independent testing service provider, TÜV Rheinland. The specialists not only test modules and components but also develop new test methods, collaborate on R&D projects for the use of solar energy and assist customers worldwide with the construction of solar power plants.

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