The photovoltaic industry in Germany knows this all too well: the European Standard EN 1991-1-4 and its National Annexes do not take sufficient account of the special features of PV systems installed on flat roofs, and there has long been a desire for a standard focussing on the planning and dimensioning of such systems. A standard with similar objectives already exists in other countries such as the Netherlands and the USA - but not yet in Germany.

In 2021, a working committee for such a standard was set up within the DIN Construction Standards Committee (NABau).

Members of the working committee include representatives of the public sector, labour and consumer protection, well-known manufacturers in the PV industry and, last but not least, I.F.I. which in its position as an institute and company has gained a great deal of know-how and years of experience in the precise determination of design wind loads for PV systems. As a result, I.F.I. was asked by the DIN Standards Committee to carry out wind tunnel tests on generic PV flat roof systems in different orientations and has presented the results during a recent meeting of the committee.

With I.F.I.'s contribution to this area, manufacturers of PV systems for flat and pitched roofs will have at their disposal a sound basis for determining realistic pressure coefficients without having to resort to the very conservative approaches of EN 1991-1-4 for the roof surfaces themselves, which do not reflect the special aerodynamic properties of PV systems.

I.F.I.'s analysis is an important step towards the finalisation of the first Draft of the Standard, which is planned for 2025.

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