2019 - Daylight Symposium
"On-site measurement of daylight autonomy : tools and methodology" by T. Severin-Fabiani, Y. Sutter
Saint Gobain Research Paris
Founder and manager
Presentation from the 8th VELUX Daylight Symposium that took place in Paris on 9 October 2019. For more information please visit http://thedaylightsite.com
Providing comfortable, healthy buildings with high energy efficiency is a key challenge for the future. Solutions that combine both safety and comfort for the occupants with sustainable approaches to address the environmental challenges have to be implemented in construction field. In this frame, new methodologies and tools to assess the comfort of occupants have to be developed. However, if technical specifications associated to artificial lighting are generally considered in construction and even if several labelling schemes are starting to take into account the fact that comfort of occupants is key for the global quality of the building, there is still a need for documented methodologies to fully assess the visual comfort of occupants, both for artificial and natural light. In this context, there is a need for extensive evaluation of the visual comfort, based on metrics and non-intrusive diagnostic but also on human experience and perceptions. Our work is focused on the development of dedicated methods to assess visual comfort in buildings.
We have developed a set of tools to quantitatively and qualitatively assess visual comfort in existing places. Two of these tools will be presented. The first one is a set of 10 wireless illuminance wifi data loggers and the second one is a newly developed occupant satisfaction survey. These tools have been used in real case studies to assess visual comfort in offices. Combined together, they aim at providing non-intrusive and quick assessment of visual comfort conditions in occupied spaces. Our results are encouraging and we trust that our assessment tools can be used outside of the research field for diagnostics and post-occupancy evaluation studies. In this presentation, we will:
• detail the two visual comfort assessment tools developed by Saint-Gobain Research,
• present the results of a one-month field study that was conducted in two offices of a building in Rouen (France), which showed that a good correlation between occupant satisfaction survey and in-situ measurements could be established.
For both offices, the illuminance distribution, artificial lighting conditions, daylight factors and daylight autonomy were measured and compared with simulations. These results were obtained with our wireless illuminance measuring devices, without the implementation of more expensive and complex set-ups that are usually required to carry out this kind of field study. We have also analysed the feasibility to use our tools to assess if the requirements detailed in the recently published EN 17037 are fulfilled.
• address the perspectives offered by these new visual comfort assessment tools, such as the possibility to use them to assess performances in the frame of environmental labelling schemes.
Tatiana Séverin-Fabiani is a research engineer working at Saint Gobain Research Paris in the Optics group since 2016. She is involved in a research program on visual comfort and daylighting, developing measurement and modeling capacities for daylight and comfort criteria. Yannick Sutter is the founder and manager of French lighting consultancy LUMIBIEN which gets involved in R&D projects mostly dealing with the perception and measurement of daylight inside buildings. Yannick also teaches building physics at the National School of Architecture of Normandy in Rouen, France.