ACCORDING TO THE U.S. DEPARTMEN T OF ENERGY (DOE),
about 160 million lamps operated in the building exterior,
parking area and roadway lighting markets in 2010. Building
exterior made up 39 percent of these lamps, parking 33 percent
and roadway 28 percent.
Building exterior (facade and grounds) lighting is considered curfew lighting, meaning it does not have to operate all
night. Area and roadway lighting is considered dusk-to-dawn
lighting, meaning light must be available all night for safety and
In 2010, LED technology achieved negligible penetration
against high-intensity discharge (HID) lamps. LED outdoor
lighting now offers efficacies nearly as high as high-pressure
sodium while providing white light, long life, controllability
and superior optical control. These benefits are driving adoption in both new and existing construction, where outdoor
lighting is now a very popular option for LED retrofits.
By 2015, the LED achieved an estimated 19 percent penetration of the installed lighting base in the outdoor stationary
market. The DOE predicts it will increase to 57 percent by 2020
and 79 percent by 2025, generating significant energy cost savings. One of the advantages of LED over HID is its superior
controllability, and lighting controls can contribute significant
additional savings and other capabilities.
Traditionally, an astronomical time switch or photocell
automatically turned outdoor lighting on and off at the circuit
level. The time switch operates according to a preset schedule
that takes into account changing sunrise and sunset times. The
photocell responds to daylight.
LEDs’ instant-on operation and ability to dim offer two control capabilities. First, occupancy sensing can be installed to
extinguish or otherwise reduce lighting when it is not being
used after hours. Second, lamps can be dimmed based on a
program. Coinciding advances in wireless intelligent control
further allow each luminaire to become a control point in a network. Using this capability, operators can remotely manage all
outdoor lighting while collecting data useful for energy analysis
and maintenance. By installing additional sensors, cameras or
audio, operators can collect other data and gain added capabilities, the foundation of a smart city.
The proliferation of LED outdoor lighting resulted in a
new standard interface that unlocks the full spectrum of
control capabilities. Traditionally, the industry was served
by standard twist-lock photocontrols featuring three pins
that turned the luminaire on or off. In 2014, the American
National Standards Institute (ANSI) C136 Roadway Lighting
Committee, in cooperation with the National Electrical Manufacturers Association, published the ANSI C136.41 standard,
which designates a seven-pin receptacle and photocontrol
for outdoor area lighting. The three core pins are identical
to the old standard. Two of the four new low-voltage pins
are used for dimming while the other two can be used for
occupancy sensing, power monitoring, two-way communication or other use.
> FOCUS BY CRAIG DILOUIE
THE BRIGHT OUTDOORS Outdoor lighting control