22 August 2006
used after testing and system design is accomplished. The following paragraphs
provide typical retrofit possibilities; however, it is stressed that lighting design changes
require proper evaluation on a case-by-case basis.
Existing Troffer Systems.
3-10.2.1 Typical Installations. Convert T-12 lighting systems to T-8 lamps and
electronic high frequency ballasts. In most cases, de-lamp 4-lamp luminaires to either
2- or 3-lamps. White painted reflectors should be installed in older parabolic troffers.
Install new lenses in lensed troffers if existing lenses are more than 7 years old.
3-10.2.2 T-12 fluorescent lamps come in a nominal 4 ft (1.2 m) length and are
therefore suitable for retrofit with T-8 lamps. T5 and T5HO lamps are a metric length
and slightly shorter than T-12 and T-8 lamps. These lamps cannot be supplied in place
of the 4 ft (1.2 m) lamps and also may not be an appropriate brightness. Luminaires
need to be specifically designed for use with T5 and T5HO lamps to control the
3-10.2.3 Special Considerations for Computer Intensive Workspace. Most lensed
troffers are not suited for computer workspaces. Consider relighting with a
direct/indirect or semi-indirect pendant system.
3-10.3.1 Typical Installations. Remove the incandescent lamp and socket, and install
a hardwired compact fluorescent adapter using a standard plug-based compact
fluorescent lamp. In many cases, replacement of the reflector is also required to
efficiently utilize the compact fluorescent lamp. Compact fluorescent lamp watts should
be about 25 percent to 30 percent of original incandescent lamp watts to achieve similar
3-10.3.2 Atypical Installations. In some cases, hardwired conversions can be difficult
or not cost effective. Use a medium based adapter with integral ballast and replaceable
compact fluorescent lamp. Compact fluorescent lamp watts should be about 25 percent
to 30 percent of original incandescent lamp watts to achieve similar light levels. These
systems normally cannot be dimmed.
Existing Fluorescent Industrial Luminaires, Wraparounds, and Strip Lights.
3-10.4.1 Replace F40T12, and F48T12 lamps and magnetic ballasts with T-8 lamps
and electronic high frequency ballasts.
3-10.4.2 For lighting systems employing F96T12 slimline and F96T12/HO lamps,
consider all of the following:
Retrofitting with electronic high frequency ballasts and continuing to use
Replacing 2.4 m (8 ft) lamps with 1.2 m (4 ft) T-8 lamps, possibly including