Daylighting
Lighting Controls
Daylighting typically refers to two separate concepts: the
Manual, automatic, or programmable microprocessor
ability of regular occupants to see outside and the
lighting controls shall be provided for all lighting, with
displacement of electric lighting due to the harvesting
the exception of exit sign branch circuitry and life safety
of daylight.
egress lighting defined by NFPA 101. The application
of these controls and the controlled zones depend on
In order to maintain a relationship between the building
a number of space factors such as: space type, frequency
occupants and the outdoors, direct views of the outside
of use, available daylighting, and typical schedule.
must be provided for at least 75% of the regularly
occupied area on above grade levels.
Microprocessor controls range from simple line voltage
automated switches to complex low-voltage lighting
If daylighting systems, beyond just windows, are to be
control panels. Lighting control systems typically include
included in the design for daylight harvesting, special
standard or astronomical time clocks, occupancy sensors,
daylighting consultants must be engaged to ensure
photosensors (light level), and override switches, but can
adequate daylight illumination, avoid common glare
include a myriad of options such as ID card readers and
issues, and assist in the integration of the lighting and
individual PC-based lighting controls.
mechanical systems with the architectural, interior, and
daylighting designs.
Time Clocks. An on/off time schedule must be included
in the control system for all lighting except security
Circuiting and Switching
lighting and lighting in spaces where occupants could
be in physical danger due to loss of light. This control
Lighting circuits shall be designed based on a realistic
system shall incorporate lighting sweeps, warning flashes,
and adequate zoning analysis. The zoning analysis must
or other methods to insure lighting is off in unoccupied
account for separate lighting control strategies, unique
spaces during scheduled unoccupied times.
occupancy areas, and maintain lighting zones smaller
than 100 m2 (1,100 sq. ft.) or one bay. Proper zoning
Occupancy Controls. Occupancy sensors shall be
allows for better control of lighting, especially during
provided for the following space and occupancy types:
after-hours operation, while proper circuiting can
Offices smaller than 30 m2 (325 sq. ft.) or with less than
minimize the complexity and cost of the lighting control
4 people.
system.
All pantries and conference rooms.
For general illumination, fixtures with more than 2 lamps
Restrooms with 3 or fewer toilets/urinals.
shall be provided with two ballasts for A/B switching or
All storage and file rooms smaller than 60 m2 (650 sq. ft.).
dimming ballasts that allow the lighting output to be
reduced to at least 50%. There maximum power penalty
Any other regularly unoccupied spaces not mentioned.
due to dimming shall be no greater than 20% of the full
Occupancy sensors shall be ultrasonic, or passive dual
power input.
sensors based on the application. Each occupancy sensor
Where applicable, tandem wiring shall be implemented
shall have a manual override and shall control no more
to reduce number of ballasts.
than one enclosed space, though some applications may
192 F A C I L I T I E S S T A N D A R D S
FOR THE
PUBLIC
BUILDINGS
SERVICE
6.8 Interior Lighting, Daylighting, and Control Systems
Revised March 2005 PBS-P100
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