IEA SHC Task 61 / EBC Annex 77: Integrated Solutions for Daylighting and Electric Lighting - Subtask A: User Perspective and Requirements. A.2 Use cases

The report starts with the introduction, chapter 1, where the main objective of the work is formulated, namely, to examine how the public buildings are used regarding lighting; both daylight and electric light is considered. In the chapter 2 a review of codes and requirements has been done. It starts with a discussion about general aspects of codes (subchapter 2.1) and presentation of international standards CEN and ISO (2.2) and follows with description of CIE reports and other internationally recognized guidance books (2.3). Then national recommendations are also presented (2.4). Finally, the impact of codes on architectural design is elaborated based on the interviews with architectural offices (2.5). Chapter 3 presents the studies of buildings usage based on the extensive literature review. The following public building types are included: offices, schools, university buildings, hospitals, commercial buildings, industry buildings and libraries. Chapter 4 focuses on occupancy and use of lighting systems. It starts with a discussion of the occupancy simulations and their usefulness in the current project context. Then, it follows with occupancy registration and use of lighting in chosen buildings located in different European countries. It includes registration in an office building in Italy, a primary school building in Norway, a university building in Poland and one industry building, also in Poland. The research method used in registration consisted of simultaneous registration of occupancy and use of (day)lighting with the help of a self-report diary, and light-technical measurements. The diary registration and the measurements were performed at the same day, in most cases in February/March 2020, that is just before the pandemic lock-down in Europe. Then, the use of electric light had been compared with the occupancy and (day)light level indoors/outdoors. The registration was carried out in each of the buildings for one day only. As such, it should be considered a form of stick sample to check the findings from the literature study presented in the chapter 3. Computer simulations were done for school and university buildings to estimate the light level during the whole year. The registration confirms a pattern of occupants’ behaviour found in literature. In general, occupants consider the visual environment at the workplace when they enter or leave the room. It happens mainly at the beginning (adjustment of blinds and switching on the electric light) and at the end of the working day (switching of the light). The use of lighting follows occupancy pattern, and not daylight level outdoors, something that indicates significant potential for energy saving. Chapter 5 Conclusions conveys general results regarding codes and more specific results regarding use of the different building types.