GSA
Courtroom Lighting Criteria Evaluation
Task 1 Report
lighting design, and can have a significant effect on both the physical quantity of light in a
space and the subjective feeling of the light on room surfaces.
3.3
Lighting Equipment
A critical component in a lighting design is the equipment used to light a space.
Luminaires, commonly known as light fixtures, contain different lamp types which have
different properties of illumination.
Tungsten-Halogen and Incandescent lamps are the simplest type of lamp technology.
They work by passing electricity through a filament, which glows, producing visible light.
The light produced by tungsten-halogen and incandescent lamps has good color rendering
(about 99). Tungsten halogen and incandescent are the least energy efficient of all typical
light sources.
Fluorescent lamps produce light by passing electricity between two electrodes in a sealed
tube. The resulting electrical arc produces UV light which excites phosphors on the tube,
causing it to glow and produce light. Fluorescent lamps are more energy efficient than
incandescent and tungsten-halogen, and are available in standard linear lengths, as well
as smaller compact fluorescent sizes suitable for downlights and other smaller luminaires.
Fluorescent lamps usually have a color rendering index of about 85, and are typically
larger than incandescent luminaires.
Metal halide lamps are in the category of high-intensity discharge lamps, and work in a
similar process to fluorescent lamps. They are the most energy efficient of the lamp types
used in architectural lighting and produce a large amount of light from relatively small
lamps. Newer ceramic metal halide lamps provide good color rendering (85+) and lamp
sizes that are suitable for architectural lighting. However, these types of lamps require a
cooling-off period of about 15 minutes after they have been turned off before they can be
turned back on, which limits their use in many situations. Traditional types that were used
in some of the reviewed courtroom installations have CRIs much too low, in the range of
60 to 65.
Page 4
X:\...-05 REPORTS & NARRATIVES0124-TASK1REPORT-DRAFT3-
Ove Arup & Partners Consulting Engineers PC
8.5X11.DOC
Issue March 1, 2006
Previous Page
