UFC 3 -520-01
June 10, 2002
F-12.1.5 Photosensors develop a signal proportional to the light in a room and dim
lights as daylight levels increase. The energy saved can be 20 percent to 30 percent of
the lighting energy without daylighting control.
F-12.1.6 Many lighting controls systems are compatible with one another. Table F -4
identifies factors that can be used for estimating energy savings impacts of combining
controls.
Table F -4. Energy Savin gs when Combining Controls
Basic Strategy
Combined with
Yields (average)
Motion sensing
Daylighting
40% 45% savings
Motion sensing
Daylighting and dimming or
45% 50% savings
tuning
Daylighting
Dimming or tuning
30% 35% savings
Daylighting
Dimming or tuning and
35% 40% savings
scheduling
Note: Energy saving yields are as compared to manual switching.
F-12.2
Minimum Requirements.
F-12.2.1 Provide the minimum lighting controls as specified by ASHRAE/IESNA/ANSI
90.1-1999. They require lighting control for each space, with a minimum requirement
for automatic controls to shut off lights when not needed. Exceptions are made for
facilities in which inadvertent or careless lighting switching could cause a hazard. The
requirements are not specific as to which type of control device, such as wall switch or
motion sensor, is to be used in specific applications. Exceptions can be made for
24-hour operation facilities.
F-12.3
Motion Sensors.
F-12.3.1 Motion sensors should be used as a primary means of lighting control in
appropriate applications. Be certain that the sensor is designed for the ambient
temperature, room geometry, and other conditions.
F-12.3.2 Motion sensors mounted into wallboxes in place of a standard switch can be
used in offices and other enclosed rooms up to 23.2 square meters (250 square feet).
Sensors should be passive infrared or ultrasonic and include a means for rapidly
relighting a space if the sensor should fail. Infrared-only sensors should be not be used
in applications where motion cannot be easily sensed in all locations, such as toilets.
F-12.3.3 Sensors designed for ceiling and upper wall mounting usually work better and
cover a larger area than wallbox sensors. Most ceiling and upper wall sensors consist
of a detector head and a remote power pack (usually a transformer -relay). Ceiling and
F-19
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