In May 2023, the Microgeneration Certification Scheme (MCS) published a new MCS 012 Solar Mounting Standard.

The new Standard ISSUE 3.0 is a significant update to the previous ISSUE 2.4. The full documents are available online at the MCS website: ISSUE 3.0 and ISSUE 2.4

Manufacturers or importers of microgeneration systems who have certificated products, or wish to have products certified, in accordance with MCS 012 may now start working in accordance with this update. According to MCS, MCS 012 compliance will only be mandatory from 10 May 2025.

MCS 012 Explained

MCS 012 requires either whole solar mounting systems or individual components to be tested and certified to various standards and requirements to ensure:

• Resistance to wind-uplift – fixing solar panels to the roofs of buildings adequately
• Fire performance and safety
• Long-term weathertightness – the roof installation provides long-term weather-proof protection of the building interior

The scope of the Standard includes:

• Products which enable above-roof installations of solar panels
• Products which enable roof-integrated installations of solar panels
• Active solar products which become part of the roof covering in roof-integrated installations

All MCS certified installation companies should be using MCS 012 approved products.  Additionally, many of the Standard requirements also apply in building regulations, which is another reason for using approved products.

What's New

The Standard Issue 3 has been substantially modified to improve its overall structure, simplify and clarify the language, and incorporate a new document layout.

The updated document includes test methods for mounting systems for use on flat roofs as well as on pitched roofs. It also categorises systems in terms of the manner of fixing, instead of either as flat or pitched roofs.

The new categories include mechanically fixed, bonded, and ballasted (including no or ‘low-ballast’).

Non-penetrating systems are now tested: PV tiles and other products where PV elements are bonded to roof coverings such as standing seam clamps.

In terms of fire performance, testing conditions are more elaborate. Overall, the Standard recommends that components or systems for mounting solar panels above roofs should be tested where any of these apply:

• They increase the gaps in a discontinuous roof covering more than would be the case without the mounting system or
• They are made from an organic material (such as wood and plastics) and inserted through gaps in a discontinuous roof covering or
• They are made from an organic material and replace any part of the roof covering
   

What MCS 012 Does Not Include

• Products whose sole purpose is to flash around brackets and hooks in above roof installations
• Products relying solely on site-applied sealants to provide a weathertight seal

About MCS

MCS certifies low-carbon products and installations used to produce electricity and heat from renewable sources. They support the growth of small scale renewables in the UK – such as solar rooftop panels on homes – through ensuring availability and quality of installers and products. The MCS is certified by the Department for Business, Energy & Industrial Strategy (BEIS) – UK.