GSA
Courtroom Lighting Criteria Evaluation
Task 1 Report
8
Recommendations
We recommend the following changes to the Design Guide to help ensure quality lighting
in future courtrooms.
8.1
Illuminance Recommendations
The Design Guide should indicate more specifically illuminance targets for task areas.
The current range of 40 to 75 footcandles is too broad, and leads to excessive amounts of
lighting and energy use. It also does not help lead the designer towards emphasizing
important areas of the courtroom with lighting, such as the bench and the witness stand.
8.2
Surface Finishes
The Design Guide should add focus on room surface finishes and contrast ratios. As
indicated in the luminance maps, surface finish has a large effect on how a room is
perceived. . Understanding the impact of dark colored walls and floor coverings on
lighting perception is critical.
8.3
Lighting Layers
The Design Guide should require a layered approach to the lighting system. Courtrooms
with predominantly directional downlighting, or only diffuse or indirect lighting performed
worse than courtrooms with a good mix of direct and indirect lighting.
Specific guidelines on the use of metal halide lighting should be clearly stated, as the
complexities of this lamp type (color rendering, ballast hum for some system, and restrike
time) need to be carefully considered when compared to their energy saving potential.
8.4
Lighting Control
The Design Guide, in addition to requiring a dimming control system, should indicate to
some level how the lighting in the courtroom should be zoned to allow for video
generation, evidence presentation, and other AV uses.
8.5
Design Confirmation During Construction
One additional issue that impacts the lighting is ensuring that the intent of the design team
is carried through construction. This requires the entire team to be involved in and
understand any modification to the design during construction, whether they be related to
value engineering, field conditions, or architectural changes.
8.6
Design Validation
The Design Guide should require the design team to verify that their design meets the
requirements. This can be done using commonly used software in the lighting design
field, such as AGI-32, or more detailed visualization using Radiance software, or one of
several other valid software packages. The key is to recognize that courtrooms present
many challenges and are more complicated than a typical building, and hence require
more detailed analysis during design than a standard building project.
An example of the value of this type of analysis is shown in the following images, which
are luminance maps of courtrooms. The first set of images are of the Islip courtroom,
Page 34
X:\...-05 REPORTS & NARRATIVES0124-TASK1REPORT-DRAFT3-
Ove Arup & Partners Consulting Engineers PC
8.5X11.DOC
Issue March 1, 2006
Previous Page
