Marley SolarTile® fact sheet Pitch perfect What the MCS012 regulations mean for roof integrated solar panels. THE MICROGENERATION CERTIFICATION SCHEME The Microgeneration Certification Scheme introduced tighter standards for pitched roofing installation of solar panels in 2016. It could be argued, though, that these requirements have always been there because of the need for every installation to comply with UK Building Regulations. Underpinning the scheme is a test procedure called MCS012, which defines a series of tests that can be used to assess the performance of pitched roofing installations for three main criteria: y weather tightness y wind uplift resistance y external spread of flame The testing regime is designed to ensure that solar installers have all the information in their hands to demonstrate that their installations do not impair the weather tightness of the roof, have adequate resistance to wind suction forces and comply with building regulations on the fire performance of roof coverings Systems and system components that are used to install solar panels above an existing pitched roof covering (on-roof systems) do not need to be tested for either weather tightness or external spread of flame, so long as they can demonstrate that the roof covering is not affected by the installation, for example, if the gaps between tiles are increased. By contrast, systems that integrate and replace the roof covering (in-roof systems) are tested for all three aspects. It is important to recognise that MCS012 sets no minimum requirement for wind resistance or fire rating, instead it takes a ‘measure and declare’ approach. It is up to the installer to check that the declared wind resistance is higher than the expected loads, and that limitations imposed by building regulations on the use of systems with lower fire ratings are observed. If the MCS012 standard itself is only a description of a test, where does the requirement to use MCS012 accredited products arise? The answer is found in the installer standards - MIS3001 for solar thermal and MIS3002 for solar PV. MIS 3002 mandates that Solar PV Microgeneration systems must be designed and installed in accordance with the “Guide to the Installation of Photovoltaic Systems”, a joint publication by MCS and ECA. Section 4.3.10 of the Guide mandates the use of MCS012 for pitched roof installations. By contrast, the solar thermal standard - MIS 3001 - does not require the installer to use products that have been tested to MCS012. However for in-roof systems solar installers will find it much easier to demonstrate compliance with the requirements of the standard by choosing an MCS012 accredited system. Both MIS3001 and MIS3002 make explicit the requirement for the installer to meet building regulations. In England and Wales approved document B deals with fire safety. Roofing materials (including roof-integrated solar panels) must have a fire rating, and depending on the fire rating achieved by the product, limitations may be placed on the size of the solar system or its maximum distance from the property boundary. Marley SolarTile® ( a Clearline Fusion product) achieved the highest possible wind resistance during testing for

PRACTICAL IMPACT ON INSTALLERS If you thought that getting ready for MCS012 was only a matter of using products that have the accreditation, think again. The test certificate merely provides the installer with declared performance values. There’s no minimum standard, no pass or fail. The wind resistance might be really high, or it might be so low you can only use the system in areas with the lowest wind speed. The fire rating might mean you can use the system anywhere on the roof, or it might mean you can only use it for a small area in the middle of the roof. The responsibility to check that...