How Brise Soleil Help Meet Building Regulations
As fixed external devices Solar shading structures are at the heart of several of the UK building compliance requirements, to ensure that Solar shading structures are used to meet the building regulations it is very important to understand which requirements they can help to meet and how they can be used to meet them before design commences to avoid expensive redesign at a late stage.
Part L and Overheating Limits
Part L of the Building Regulations for new buildings sets a maximum level of solar gain that is allowed into a building. This is checked using SAP or SBEM models and takes into account any fixed external shading devices. This means that the blade geometry of any Brise Soleil is crucial and must be modelled in prior to detailed drawings being produced for the external envelope of the building. This avoids the risk of expensive redesign later down the line.
Part O for Residential Schemes
From 2022 new residential buildings in England have to comply with Part O, the new overheating standard. The approved document O for residential buildings in England contains guidance on overheating. Brise Soleil external shading reduces the peak solar irradiance on a glazed façade, thus simplifying and enhancing compliance with the limits set out in the approved document as well as with the more detailed dynamic thermal simulations required as an alternative.
Blade Angle and Projection Depth
The angle of the blade, the depth of the blade’s projection relative to the height of the glazing and the reflectivity of the blade material all need to be specified and confirmed by the Assessor and building control inspectors. Changes to any of these after sign-off off of the building will need to be rerun through the thermal model.
BREEAM Credits
For BREEAM Hea 04 thermal comfort assessment a dynamic overheating simulation is required. The number of hours above 26°C must be less than a threshold value. Solar shading, in the form of external shading devices, is one of the most effective methods of achieving the credit.
Conservation Area Planning
For listed buildings or buildings in conservation areas, any external shading structure is considered to be a visible alteration to the building. It is wise to seek pre-application advice from the local planning authority before specifying a solar shading structure. The planners may require approval of the blade profile, finish and method of fixing.
Ensure all details of your Brise Soleil’s specification are correct from the beginning to ensure compliance is achievable.