GSA
Courtroom Lighting Criteria Evaluation
Task 1 Report
Vertical Illuminance (Fc)
5.3.6
Design Analysis
Horizontal Illuminance (Fc)
There are several notable findings in this
120
courtroom lighting scheme:
110
Overall illuminance levels for the different
task areas exceed IES recommendations
100
significantly in almost all task areas.
90
Illuminance levels exceed the higher
Design Guide recommendations for
80
several important areas, including the
c rs ek n tewtes tn , h h
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c
70
had an illuminance of 117 footcandles,
50% higher than the recommendation.
60
Because of the relatively dark wood
50
panelling that covers the entire wall height,
the room seems dim because of the high
40
contrast to the illuminated ceiling. The
30
average luminance of the illuminated
ceiling is around 1500 cd/m. When
20
compared to the 30 cd/m walls this
produces a 50:1 contrast ratio, which is
10
excessive and leads to the ceiling being
seen as a glare source.
0
Because of the low reflectance and
specularity of the wood panelling, the cove
lighting at the front and back of the room
does little to light the room other than
provide a visual accent at the top of the
LPD w/sf
2.9
wall.
Limit w/sf
1.9
1
2
3
4
5
The use of direct metal halide downlight
luminaires directly contradicts the Design
Guide. Users of this courtroom noted that
Subjective Rating
the re-strike time for the metal halide
5
downlights and the limited zoning severely
4
3
impaired the courtrooms ability to adapt to
2
video presentations.
1
Dimming control is not provided, which is a
requirement in the design guide, which
further limits the flexibility of the lighting
system.
Satisfaction?
NY
Page 19
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Ove Arup & Partners Consulting Engineers PC
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Issue March 1, 2006
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