2009 - Daylight Symposium
PROSPECTIVE DESIGN IMPLICATIONS OF RECENT FINDINGS IN PHOTOBIOLOGY by Marilyne Andersen
Speakers
Marilyne Andersen
Professor
EPFL
Recent studies have attempted to link environmental cues, such as lighting, with human performance and health, and initial findings seem to indicate a positive correlation between the two. Insufficient or inappropriate light exposure can disrupt normal circadian rhythms which may result in adverse consequences for human performance, health and safety. This presentation will discuss how the current state of the art in photobiology can prospectively be applied to architectural design, with a focus on healthcare and housing environments.
Outcomes of photobiology research were used in the presented work to define threshold values for illumination in terms of spectrum, intensity, and timing of light at the human eye, and were translated into goals for simulation – and ultimately for building design. In particular, the climatebased Daylight Autonomy (DA) metric was chosen to simulate the probabilistic and temporal potential of daylight for human health needs.
While no actual recommendations can – or should – yet be made because of our limited understanding of the effects of exposure to light on human health and circadian organization, especially during daytime, we can still discuss the relevance of some critical design parameters to electric lighting or – to a greater extent – daylighting. Typically, factors most influential on the perceived light spectrum, intensity and duration should be analyzed such as luminaire type, glazing fraction, interior surface reflectances, façade orientation, space use and dominant view directions.
The field of circadian daylighting in architecture is a new one. Because photometric quantities such as lumens are keyed to visible light rather than circadian sensing-shifted light, they are not useful to determine if a space has sufficient light of the correct spectrum for circadian realignment without considerable calculations. The work that will be discussed should lead to a better understanding of the relative effect of design decisions such as window size, position and materials; two particularly representative case studies were chosen to test the developed methods, namely hospital rooms and Boston rowhouses. This pioneering work opens up the discussion to design and renovation suggestions, keeping in mind that given the very early development stage of photobiology in this field, any finding has to be considered as a possible approach to solve the problem rather than as absolute design guidelines.
Marilyne Andersen is a physics engineer whose principal research interests are the use and optimization of daylight in buildings, which led her to inter-disciplinary exchanges between architecture, physics and environmental concerns. At MIT (Massachusetts Institute of Technology), she leads the Daylighting Lab since 2004.
Her current research focuses on advanced glazing and shading systems, on daylight redirecting devices, on visual and thermal comfort and the design implications of light on health, as well as on the visualization of daylighting performance and metrics in design.
