MIT Sustainable Design Lab
Lorax Project | Giving Architects A Voice In Daylighting Standards

Christoph Reinhart, Tarek Rakha and Dan Weissman (supported by an MIT HASS grant; 2012 - 2014)
Pilot Study

Standard organizations and committees working on building codes and green building standards are typically not frequented by architects. Yet, these committees do more and more influence what performance criteria architects have to design for. This situation is undesirable since there is not feedback mechanism that reports how standard requirements influence design decisions in practice. The ambition of this project is to bring some of the questions raised in committees into schools of architecture, to have students and faculty contribute to these questions and to report the findings back to the standards world.

Pilot Study In recent years climate-based daylighting metrics, in particular daylight autonomy, have found their way into North American standards and green building rating systems. An open question remains what a daylight autonomy simulation actually mean for building occupants and designers. To further our understanding in this regard, we developed and tested a classroom exercise called the "daylit area study". It is a hands-on exercise, suitable for any university level course or module on daylighting. All you need is a daylit space and a light meter. The space should be deep enough so that there are actually parts of it that occupants might consider to be "non daylit". During the exercise participants are first asked to draw the daylit boundary in the space following their intuition and to then conduct a few illuminance measurements. The instructor then plots all student assessments onto a single floor plan and determines the mean daylit area for the space along with a series of daylight simulations. The educational value of the exercise is that participants understand what their personal target illuminance for a given space type is and how their personal approach to daylight compares to current and emerging daylighting metrics. The value for research is that we gain more insight into how well our metrics mimic occupant assessments. During a pilot study in the Carpenter Center at Harvard we found that subjective space evaluations by architecture students correlated well with daylight-autonomy-based daylit area simulations (see images below). a href="" target="_blank">Pilot Study>>

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1 - Our pilot study was conducted in Le Corbusier's Carpenter Center in Cambridge, MA.

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2 - Sixty-seven architecture students sketched the daylit area in the 2nd floor studio.

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3 - Daylit area according to IESNA DA300lux[50%] and mean student assessment.

Main Study Between 2012 and 2013 we collaborated with educators at 11 schools of architecture and applied the daylit area study consistently to 13 spaces within the participating schools. The schools are located in Brazil (2), Canada (1), Egypt (1) and the United States (7). For the study we introduced the concept of a “partially daylight area” metric based on a minimum illuminance threshold for daylight autonomy of 150lux. The findings suggest that daylight autonomy based simulations should be adopted by both designers and rating systems.