Rinat Hadashi-Gannon
M.Sc.Thesis, 2023
ABSTRACT:
Light significantly affects human physiological and psychological health, well-being and performance. Its non-image-forming effects include the biological clock and circadian rhythms, neurological and hormonal processes. People in modern societies spend 90% of their time indoors, suffering adverse health effects caused by insufficient daylight and exposure to artificial light sources that disrupt circadian rhythms. The field of research linking human health and the built environment repeatedly identifies daylight’s contribution to health, well-being and performance. Lack of awareness, performance metrics, guidelines and regulations, lead many professionals and designers to address only visual and energy aspects of lighting. In healthcare, daylight is linked to positive patients’ outcomes, including reduced length- of-stay (LOS), lower pain perception and medication consumption, reduced depression and stress, sleep improvement and more. In semi-private patient rooms, common in Israel, patients in beds far from the window are exposed to low daylight levels, caused by distance from the light source, user behavior and lack of awareness.
This study aims to evaluate and link architectural design to health-promoting daylighting – how architectural façade design may enhance daylight availability and improve patients’ outcomes and well-being. Criteria and metrics for health-promoting daylighting were studied, and a methodical framework developed to evaluate the performance of architectural means according to the established daylighting measures. Simulations of a typical sidelit two-bed inpatient room were used to evaluate of the effect of architectural façade design alternatives on daylight availability, its quantity, duration of exposure and visual discomfort. Simple architectural means, including daylight windows, overhangs and light-shelves, were selected for evaluation, due to scope and the wish to consider low-cost and maintenance alternatives, in-line with Israeli health-system’s constraints.
Findings indicate that even simple architectural means may significantly improve daylighting levels, with relatively small influence on visual discomfort. Daylighting for patients in far beds can be elevated from minimal to health-promoting levels. Orientation-based design recommendations can be made for room and bed locations. Seasonal performance evaluations were identified as important for design analysis and improvement, rather than commonly-used annual ones, since significant differences found in daily seasonal results for different orientations may influence health- outcomes for short hospitalization periods. Seasonal design adjustments for each orientation can improve low daylighting levels and reduce visual discomfort. Fully operable blinds, allowing angle-adjustments and full-opening – seldom installed in newly-built patient-room windows in Israel – were identified as important to improve daylighting levels, visual comfort and patient-satisfaction.
This study portrays the applicability of the proposed framework to evaluate design by daylighting performance measures, inform façade design, and identify beneficial design strategies for health-outcomes. It can be applied for other facilities where daylight was linked to health and performance-outcomes, as education and work environments.
Research-based knowledge of health-promoting daylighting levels and characteristics is needed to develop better performance measures and benchmarks, guide and improve design, and support a business-case. All stake-holders – building occupants, CEO’s, staff and, most of all, designers – need higher awareness of light’s impacts on human health and of the important role of the built-environment’s design and use- patterns in human health, well-being and outcomes.