Center for Integrated Building Design Research Jan 2009 | Page 52

ARTIFICIAL SKY

More on Luminance

Fenestration Testing

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The first iteration of our “informed case” opens the roof by
increasing the angle from the intersection of the south facade
to the point of intersection with the northern most interior
atrium wall. Later, the roof plane was raised 9’ which opened
the ceiling condition to an 8’x12’ opening to the north,
measuring an overall increase of at least 30 foot candles from
our base case luminance studies. In the second iteration, the
roof plane was cut at the intersections of both interior atrium
walls and raised 5’ while maintaining the same angle. This
iteration (the graph on the lower right) proves the benefit
of bilateral light across the ceiling condition and below to
creating balanced illuminance. This iteration reduces the
clipping effect of the higher floor plane and effectively raises
the luminance levels beneath an additional 5-15 footcandles
up to 10’ beyond the atrium wall without over illuminating
the second floor space.