Proposal for revised criteria for daylight provision for the European Daylight Standard EN 17037:2018+A1

Abstract

The European daylight standard EN 17037 was first introduced in 2018 with the aim of encouraging building designers to evaluate and ensure adequate daylight provision in buildings. However, experience has shown that the standard’s criteria are generally perceived to be too challenging to achieve. Therefore, to suggest a more balanced threshold, this master’s thesis aims to investigate compliance rate of existing buildings in Sweden for daylight provision criteria. In this study, 30 residential buildings in Sweden with a total of 3,570 rooms were selected based on Swedish building typical building forms and evaluated through Radiance-based daylight simulations using three different approaches: (1) Daylight Factor-based methods, (2) LM-83-12 method, and (3) a modified EN 17037 calculation method using illuminance level which is largely based on spatial Daylight Autonomy (sDA). In relation to the latter, compliance was checked for different combinations of illuminance thresholds and targeted area fractions. Then these compliance rates and the different combinations of the illuminance threshold as well as the targeted area fraction were compared to existing standards. Finally, a new criterion with three level of recommendations were proposed based on the new method. Results revealed that a large proportion of the examined individual rooms were able to meet various criteria for daylight provision. However, when looking at the buildings as a whole, only a few of them were able to fully meet these criteria. This is because a large proportion of the buildings have critical rooms that have limited access to the daylight, which makes it difficult to achieve the desired level of daylight provision at the building level. Furthermore, the finding of the study indicates that employing an illuminance threshold of 300 lux may not be beneficial in the context of the new criteria. Rather, a lower threshold coupled with a higher targeted area fraction would increase compliance and could be proposed as an alternative, but it needs to be backed up by further research.

Popular Abstract

European Union published the first daylight standard (EN 17037) in 2018 aiming to encourage designers to consider and ensure daylight provision in buildings. However, the current standard is found to be too ambitious. Therefore, this study explores new sets of daylight criteria that could redefine good daylight in residential buildings, and it should ensure a fair compliance rate that could reflect the existing building market norm.

In this study, 30 multi-family residential buildings were studied for their daylight availability according to different standards, including Swedish Building Regulation (BBR), LM-83-12 (developed by Illuminance Engineering Society) and the current European Daylight Standard (EN 17037). In these different standards, the buildings’ daylight performance would be assessed through either daylight factor method, or illuminance-based method. In daylight method, the buildings would only be assessed according to their geometry and shading from the surrounding buildings, regardless the buildings’ location or orientation. And in the illuminance-based method, the buildings were simulated with real weather data, to understand the illuminance level that each room could achieve in certain fraction of the room area, according to the location defined in the weather data. Then, new sets of criteria would be suggested according to the compliance rate of different illuminance and area fraction. And the consequences and impact on future design would be discussed for each set of criterion.

Results revealed that a large proportion of the examined individual rooms were able to meet various
criteria for daylight provision. However, when looking at the buildings as a whole, only a few of them were
able to fully meet these criteria. This is because a large proportion of the buildings have critical rooms that
have limited access to the daylight, which makes it difficult to achieve the desired level of daylight provision at the building level. Furthermore, the finding of the study indicates that employing an illuminance threshold of 300 lux (the minimum level in the current EN 17037) may not be beneficial in the context of the new criteria. Rather, a lower threshold coupled with a higher targeted area fraction would increase compliance and could be proposed as an alternative, but it needs to be backed up by further research.

The limitation in this study is that only 30 Swedish buildings were accessed. Considering that the daylight standard would be applied to the whole Europe, it would be beneficial to have parallel study in the southern Europe where the climate differs significantly.

• author: Jin, Zhengyu and Chen, Xintong
• supervisor: Niko Gentile; Paul Rogers; Angel Perez Morata; Helle Rasmussen
• organization: Division of Energy and Building Design; Department of Architecture and Built Environment
• course: AEBM01 20231
• year: 2023
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Daylight, Residential, European Standards, Compliance, Spatial Daylight Autonomy
• language: English
• id: 9120100
• date added to LUP: 2023-06-09 15:25:58
• date last changed: 2023-06-09 15:25:58