VELUX Commercial explores the new European daylighting standard and what this means for building design
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The new European Standard EN 17037 is the first of its kind to deal exclusively with the design for, and provision of, daylight in buildings. It replaces a patchwork of standards across different European countries or provides one where no existing standard is present. Daylight is important for the health and wellbeing of building users, for providing sufficient illumination to carry out tasks, and for giving a connection to the outdoors. Providing appropriate levels of daylight also helps to save energy by not relying on artificial lighting as often. All these factors have driven EN 17037’s publication.
Are there existing daylight design standards?
BS 8206-2:2008 is the code of practice for daylighting. As it’s a British Standard, it applies to the UK only and gives recommendations for daylight design in buildings, including how electric lighting can be used in conjunction with daylight.
EN 17037 deals exclusively with daylight and includes other methods of calculation for different design parameters that don’t feature in BS 8206-2. This means that the new European Standard can be used to assess daylight design in buildings for accreditation schemes, such as the WELL Standard.
Some existing European Standards include daylight as a factor, for example EN 12464-1 and EN 15193. However, both of these looks at it in the context of electric lighting provision. EN 17037 is truly unique in focusing on the quantity and quality of daylight for building users.
When does EN 17037 come into force?
As a European Standard, adoption of EN 17037 across member countries will be staggered, depending on when it is incorporated into national standard frameworks. In the UK, it’ll become effective by the end of 2019, and any conflicting national standard (such as BS 8206-2) will have to be withdrawn by mid-2019.
In the short term, this variation at the national level could mean confusion for anybody working on projects in different countries. They could find themselves applying the standard on one project, but not on another. In the long term, of course, the benefit will be that the requirements can be consistently applied. Even where designers and specifiers are only working in the UK market, it will still take time to get fully up to speed with the requirements of the new standard.
How is the provision of daylighting design measured?
EN 17037 sets a minimum level of performance that must be achieved for each of the four areas of daylighting design. This provides flexibility for architects and designers, while also making the standard useable and understandable.
As well as the minimum recommendation, it also gives two further performance levels: medium and high. Users of the standard are free to select the performance level that best relates to the building design and proposed building use.
A simplified and detailed method is available with which to assess each design area. The standard harmonises the evaluation of daylighting, but takes into account national and local conditions so that solutions are appropriate and specific to each project.
Designing for daylight and building occupant comfort
Daylight provision or illuminance levels allow users to carry out tasks and play a part in determining the likelihood of artificial lighting being switched on. Assessment can be via either climate-based modelling or daylight factor calculations.
Building users should have a large and 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). The view should be perceived to be clear, undistorted and neutrally coloured. 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.
Calculating access or exposure to sunlight is a comfort and health factor for building users. Daily sunlight exposure can be established through detailed calculation or table values.
As its name suggests, prevention of glare is concerned with removing the probability of glare for building users, especially those who do not choose where they sit. It uses a detailed calculation of daylight glare probability (DGP) or a standard table of values for sun-screening materials.
VELUX Commercial  has spent time understanding the calculation methods detailed in EN 17037 in relation to rooflights, and is on hand to provide technical support and answer any questions about how our products can improve daylighting in your commercial project.
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