LIGHTING BY CRAIG DILOUIE
The Department of Energy requires
states to adopt a code at least as stringent
as ASHRAE/IES 90. 1 2013 by September
2016. Since the 2015 IECC would be equivalent, it will likely see significant adoption.
The 2015 IECC follows the 2012 version with more restrictive lighting-power
allowances. The Building Area Method
lighting-power allowances are roughly
in alignment with the ASHRAE/IES 90. 1
2013 energy standard. Power allowances
were adjusted down from 0.9 watts per
square foot (W/sq.ft.) to 0.82W/sq.ft.
for offices, 1. 4–1. 26 for retail, 1. 2–0.87
for schools/universities, and 1.0–0.9 for
healthcare clinics. Warehouses saw an
increase from 0.6–0.66W/sq.ft.
The most extensive changes in the
IECC 2015 are in lighting controls. Consult the code and the authority having
jurisdiction for specific requirements and
interpretation related to your project.
Interior automatic lighting shutoff
With few exceptions, interior lighting
must be turned off when not in use. Occupancy or time-switch control can be used.
Occupancy sensors are required in a list
of specific applications, including classrooms, private offices and warehouses.
The sensor must be manual-on or auto-on
to maximum 50 percent of lighting power
(except in warehouses), must turn lights
off within 30 minutes of vacancy, and give
occupants manual-off capability. In warehouses, the sensor must reduce lighting
power by at least 50 percent after the aisle
is vacated, be zoned to a single aisle, and
must not control lighting outside the aisle.
Time-switch controls must be installed
where occupancy sensors are not. The control must feature a minimum seven-day
clock, backup capability in case of a power
interruption, and holiday programming. A
manual override switch must be provided.
The manual override switch allows occupants to use their local lighting, with the
override area limited to 5,000 sq.ft. and
time limited to two hours (which may be
renewed by resetting the switch). It also
provides basic manual control.
Some malls and industrial buildings
allow up to 20,000 sq.ft. as the override control zone, and the time limit is
extendable as long as the override switch
is a captive key device.
The switch must be readily accessible with the controlled lighting in view.
The switch may be installed remotely if
it identifies the location and status of the
controlled lighting. It must be capable
of light-reduction control, providing the
ability to reduce lighting power by at least
50 percent in a reasonably uniform illumination pattern, using multilevel switching
or continuous or step-dimming.
Automatic daylight-responsive lighting
controls are required in applicable sidelighted (e.g., windowed) and toplighted
(e.g., skylighted) daylight zones. The
automatic controls must be capable of
turning the lights off. In offices, classrooms, laboratories and library reading
rooms, they must be capable of continuous dimming to 15 percent or less of full
light output. The controls must be capable of being calibrated, with ready access,
IECC 2015 identifies special applications
and presents requirements for lighting
controls. For example, display and accent
lighting must be controlled independently,
and supplemental task lighting must be
controlled by an integral control device or
accessible wall-mounted control.
Exterior lighting control
All lighting must be capable of being
turned off automatically in response to
daylight (photosensor). Building facade
and landscape lighting must also be
capable of turning off at a set time after
hours (astronomical time switch). Other
lighting must be reduced by at least 30
percent after hours in response to a time
event or occupancy (occupancy sensor).
More energy-efficiency options
IECC 2015 requires the designer to optimize energy efficiency. One option is to
comply with lighting-power allowances
adjusted by a factor of 0.90. The second is
to install a digital lighting control system
capable of continuous dimming, individual
luminaire addressability, load shedding,
reconfiguration, and occupant control of
overhead lighting in open offices.
IECC 2015 requires commissioning of
the building’s power and lighting systems. Documentation requirements
include a lighting and control narrative,
operating and maintenance manuals,
submittal data indicating all selected
options for lighting and controls, and an
inspection and recalibration schedule for
lighting controls. The IECC also requires
functional testing for automatic lighting
control, and it has specific requirements
for each control type.
The IECC has evolved in three major
directions—greater alignment with
90. 1, lower lighting-power allowances
and broader control requirements, all
of which increased the complexity of
lighting. For more information, consult
the IECC 2015.
Meet the New Code
The 2015 IECC has evolved in three areas
LAST YEAR, the International Code Council published the 2015 International Energy
Conservation Code (IECC), a model energy code that states and other jurisdictions
can use in whole or part as their energy code. Today, many states base their commercial building energy code on the IECC.
DILOUIE, L.C., a lighting industry journalist, analyst and marketing consultant, is
principal of ZING Communications. He can be reached at www.zinginc.com. S H