BRE IP14/12 PDF

INTRO DUCTION

An NHBC Foundation guide to the installation of renewable energy systems on roofs of residential buildings, NF30[1], has been published recently. This guide covers wind turbines, as well as passive systems such as photovoltaics (PV) and solar thermal panels. Several problems encountered by the inappropriate mounting of small wind turbines to buildings are discussed, and the guide includes a new simplified theoretical approach for determining wind loads on microwind turbines attached to buildings.

Wind turbines now vary enormously in size, and microwind turbines are generally considered to be wind turbines having a rotor diameter of less than 2 m. These turbines are usually pole mounted and generate static and dynamic wind loads, which are then transmitted to the building. This Information Paper gives the background information on the full-scale measurements and wind tunnel testing. The findings of these studies enabled theoretical expressions to be derived for wind loads. Simplified equations are given in NF30 that enable dynamic wind turbine mounting bracket shear forces and bending moments to be calculated.

Details of the testing and the theoretical derivation itself are not published in the NHBC Foundation guide, and reference to this Information Paper is made in the guide. This Information Paper both provides information about the testing undertaken at BRE and gives the detailed derivation of the expressions.