The 3rd edition of the BRE guidance on daylight & sunlight amenity was published in June 2022. The BRE guide now contains the UK annex of BS EN 17037, which replaces the previous guidance under BS 8206-2:2008 Code of practice for daylighting. The new testing metrics contained within the 3rd edition of the BRE guide relate to the adequacy of daylight & sunlight within new dwellings and also consider view out and glare.  They are summarised below:

Daylight provision

Daylight provision, or illuminance levels, determine the amount of available daylight in habitable rooms. The Average Daylight Factor and Daylight Distribution tests in BS 8206 have been replaced with either climate-based modelling (the illuminance method) or daylight factor calculations.

Sunlight exposure

Exposure to sunlight is now calculated using a climate-based approach to determine whether habitable rooms receive at least 1.5 hours of sunlight on a given date (21 March is the recommended date in the UK).

Assessment of the view out of windows

Wherever possible, occupants of buildings should have a large, clear view of the outside. EN 17037 considers the width and outside distance of the view, as well as landscape ‘layers’ (sky, landscape and ground). Width of view can be established via a detailed or simplified approach. Outside distance and number of layers are each measured by a single approach.

Prevention of glare

Prevention of glare is concerned with removing the probability of glare causing discomfort for building users, especially those who are not able to choose where they sit. It uses a detailed calculation of daylight glare probability (DGP).

Hollis prepared for the launch of BS EN 17037 and since it has come into use, via the publication of the new edition of the BRE guide in June 2022, we have been providing advice and reports to support developers’ planning applications across the UK and in Ireland.

If you have any questions or would like us to present a CPD session to provide more detail on the new assessment techniques and how to minimize planning risk through daylight design, we would be delighted to help.

Ian McKenna

Rights of light and daylight and sunlight

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