The BRE has published new advice on Site Layout for Daylight and Sunlight this week. The new publication ‘Site layout planning for daylight and sunlight: a guide to good practice’ (BR209 2022) is the 3rd revision published by the BRE, replacing the previous edition issued in 2011.
The guidance contained in the revised advice has been amended to incorporate updates from the British Standard for Daylighting in Buildings (BS EN17037) issued in June 2019. The BRE guidance is widely relied on by planning authorities when assessing proposed new developments for Daylight and Sunlight.
The new guidance recommends the assessment of natural light conditions for all residential planning applications with a fundamentally different approach. It also introduces a requirement to assess other non-residential uses for the first time.
New Daylight & Sunlight Guidance - Key Observations
- The guidance for considering the effect on neighbouring properties and open spaces remains consistent with the previous version of the BRE Report.
- The previous version of the BRE Guide discussed daylight and sunlight within homes, schools, hotels and hospitals but did not apply guidance to workspace. The updated guidance applies to the above uses and additionally provides guidance for workshops and some offices.
- The adoption of BS EN 17037 changes the tests to be applied when assessing the adequacy of natural light within proposed accommodation.
- The previous daylight tests of Average Daylight Factor (ADF) and Daylight Distribution (DD)/No-Sky Line for assessing the adequacy of daylight within proposed accommodation are superseded.
- Daylight in proposed accommodation is to be assessed with reference to the area of the room achieving target daylight factors. An alternative test using target illuminance (lux) value is also provided. Both of these assessments take account of internally and externally reflected natural light as part of the calculation. The target illuminance assessment also introduces time criterion.
- The previous sunlight test of Annual Probable Sunlight Hours (APSH) for assessing the adequacy of sunlight within proposed accommodation is superseded.
- Sunlight in proposed accommodation is now to be tested on any date between February 1st and March 21st, with minimum (1.5 hours), medium (3 hours) and high (4 hours) levels of sunlight determined. The criterion applies to rooms of all orientations, although the guidance acknowledges that if a room faces significantly north of due east or west it is unlikely to be met.
- Further assessments for View and Glare are introduced
New approach to Daylight & Sunlight Assessment
The updated methods of considering the adequacy of natural light within proposed accommodation are significantly different from the assessment approaches that the development and planning world are familiar with. In many respects, the updated guidance marks a move away from simplistic calculation and responds to the more sophisticated methods of analysing light now possible by advancements in software technology.
We provided input to the new BRE guidance whilst it was in draft consultation phase and have been working with our software partners since the introduction of the British Standard in June 2019. We incorporated the revised methods of assessments and have been referring to them on projects for some time. The new good practice guidance from the BRE on Daylight and Sunlight is available from the BRE Bookshop.
Local planning authorities, developers, architects and planning consultants will need to familiarise themselves with this fundamental shift in approach to ensure that the design of proposed schemes and the determination of planning applications apply the updated guidance correctly.
We are expert in undertaking the revised calculations and understanding their implications for proposed developments. Please get in touch if you would like further advice or to arrange a CPD session with our team.
For advice on Daylight & Sunlight direct from one of our surveyors, please call our Daylight & Sunlight Enquiry Line on 020 4534 3138.
If you would like us to call you, please fill in our Contact Us form and we will call you back.
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If your proposed scheme is in Birmingham, see our recent article on the adoption of Daylight and Sunlight Assessments by the City.