MCS Leads on Solar PV Fire Testing Classifications

THE ORGANISATION set up to oversee renewables installations is trying to steer a response to changes in fire testing solar PV modules.

The Microgeneration Certification Scheme (MCS) Solar Mounting Working Group is orchestrating a response to changes in the European standard which happened in September 2023.

The change meant that fire test laboratories are no longer able to issue a fire classification for solar PV modules.

Some solar PV products require a fire classification for certification against The Solar Mounting Product Standard (MCS012).

However, where solar products form a roof covering (roof-integrated solar systems) a fire classification is required. This is so that they comply with Building Regulation B4: External fire spread.

Any new products brought to market are currently unable to obtain a fire classification and so cannot be integrated into roofs in compliance with the Building Regulations. This also prevents them gaining MCS certification.

Fire Classifications for Solar

Fire classifications for construction products are defined in BS EN 13501-5, relating to test methods set out in CEN/TS 1187:2012. So, for example, a classification of Broof (t4) is based upon Test 4 of CEN/TS 1187:2012.

Both BS EN 13501-5 and CEN/TS 1187 apply specifically to construction products, as defined in the Construction Products Regulations.

However, solar PV products are not listed as construction products in those regulations.

This was not previously an issue because test laboratories were able to use their own expert opinion for extended application (EXAP), under BS EN 15725, in turn extending the testing scope of CEN/TS 1187.

Changes to Solar Fire Testing

However, BS EN 15725:2023, which took effect in September 2023 (when the previous version was withdrawn) removed expert opinion as a process that could be used for EXAP.

Approved Document B currently details a transposition table (Table B2) between classifications according to BS EN 13501-5 and BS 476-3. It presents a possible solution, as the changes to BS EN 15725:2023 do not apply to BS 476-3 so in theory extended application of the test is still possible with expert opinion.

However, it is the intention of the UK Government to remove this transposition table from Approved Document B so only classifications according to BS EN 13501-5 will be valid, closing off a potential interim solution.

MCS Lead

MCS has convened several meetings to try and find a solution. They’ve met with representatives from the Building Safety Regulator, the Northern Irish, Welsh and Scottish governments, fire test laboratories and BSI (specifically the Chair and Secretariat for FSH22-8 as the committee responsible for BS 476-3).

MCS has stressed the urgent need for a solution as, without one, the UK’s deployment of solar PV could be harmed.

Possible solutions

As Approved Document B will remove reference to BS 476-3 there is a question over a transition period. So, there is still a possibility that testing and classification according to BS 476-3 (in an edited form for the purpose of testing solar PV products) might be a temporary solution whilst representations are made to the European committee responsible for BS EN 15725.

MCS says it is urgently seeking a response from BSI on the possibility of updating BS 476-3 (or re-writing a version of it) to better apply to solar PV products.

They are also looking for clarification from the Ministry of Housing, Communities and Local Government (MHCLG) on the transition period for the removal of BS 476-3 from Approved Document B.

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