People are asking lighting designers to help them save on energy costs, and replacing fluorescent, HID, or other lights with LEDs is in high demand. This article looks at the codes and guidelines that define LED use.

1. LED codes and standards
Clients are asking lighting designers to help them save on energy costs, and
replacing fluorescent, HID, or other lights with LEDs is in high demand. This article
looks at the codes and guidelines that define LED use.
Tom Divine, PE, LEED AP, Smith Seckman Reid Inc., Houston
04/19/2016
Learning objectives:
 Outline the codes and standards that dictate designing with LEDs.
 Compare and contrast the benefits and drawbacks to LEDs.
 Evaluate the use of lighting controls.
Nearly all commercial facilities in the United States are governed by one of
three energy-conservation codes:
 ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-
Rise Residential Buildings
 International Energy Conservation Code (IECC) from the International
Code Council
 California Title 24: California Energy Code.
For this article, these codes will be referenced as ASHRAE 90.1, IECC, Title
24, and collectively as "the codes."
Each code describes requirements for lighting, in terms of the total lighting
power allowed, along with prescriptive requirements regarding lighting
controls and operation. Most jurisdictions require that a project design
complies with ASHRAE 90.1 or IECC, and California projects are governed by
Title 24.

2. ASHRAE 90.1 can be considered the standard energy code for the United
States. The federal Energy Policy Act of 2005 (EPAct), as amended, requires
that states adopt an energy code at least as stringent as whatever edition of
ASHRAE 90.1 is found to be most stringent by the Department of Energy
(DoE). Title 24, directly enforceable only in California, operates to some
degree as a bellwether code—significant changes to ASHRAE 90.1 and IECC
often appear first in Title 24 and then migrate to future editions of the other
two codes.
These codes and their predecessors can exert substantial influence on
lighting markets. For example, California Title 20, 1605.1(l), included by
reference in California Title 24, requires that exit signs consume no more than
5 W per face, echoing the requirements of the EPAct. That level is difficult to
achieve with fluorescent lamps, and impossible with incandescent lamps. The
requirement had the effect of creating a de facto requirement for LED drivers
in exit signs. Today, practically every exit sign uses LEDs as its light source.
The primary intent of the codes is to ensure that the built environment uses
less energy than it would in their absence. One of their secondary purposes is
to foster technologies that show promise for future energy conservation. LED
lighting currently looks to be one of those technologies, and we can expect the
codes to include requirements that foster its development and acceptance to
the extent that those requirements are reasonably achievable and don't
conflict with the codes' primary purpose.

3. This article isn't intended to describe how to achieve compliance with these
codes. Each code describes a Byzantine maze of decision trees, exceptions,
and alternate compliance methods. A thorough treatment of any of them is
well beyond the scope of this article. Rather, this article qualitatively describes
some of the requirements of the codes covering lighting systems, with
particular emphasis on new requirements in common among them, and how
those requirements affect design decisions regarding LED lighting.
LED benefits and drawbacks
LED lighting offers a number of advantages over more traditional
technologies. They exhibit very long lifetimes as compared with fluorescent
lamps, and consequently have lower maintenance requirements. They're
robust and much more resistant to physical damage than fluorescent lamps.
They're insensitive to cycling, and can be energized repeatedly without
reducing their life. Their ultraviolet and infrared emissions are extremely low
compared with other sources. And, they don't contain environmentally
troublesome ingredients, making their ultimate disposal a simple matter.
LED lighting also brings advantages that are specifically interesting in regard
to energy conservation:
 Efficiency: The luminous efficacy of LED luminaires is generally
competitive with fluorescent fixtures, and fixtures with high-end LED
emitters can exceed the efficacy of the best fluorescent fixtures. In
addition to direct energy savings, high efficiency reduces HVAC costs
during heating seasons and in interior zones.
 Dimmability: LEDs are easily dimmable, as a consequence of the
technology used to provide the constant direct current (dc) that drives
them. Adding dimming capability to an LED fixture is inexpensive as
compared with fluorescent fixtures.
 Controllability: LEDs come to full brightness almost immediately after
they're energized, while fluorescents can take many seconds or a few
minutes to reach maximum output.
 LEDs are much less sensitive to cold temperatures than fluorescent
lamps, making them well suited for outdoor use.
At the same time, LEDs bring significant disadvantages:
 LED lighting is generally more expensive than fluorescent lighting in
terms of similar effective light output, build quality, and appearance.

4.  The market for LED fixtures and lamps is, if not in its infancy, certainly
preadolescent. There are few standards, few long-term manufacturers,
and limited information. Most LED emitters have life ratings that are
considerably longer than the age of the product. Producers can enter
and exit the market quite quickly, and there's often little reason to
believe that a particular device will still be in production when the first
unit fails and has to be replaced. These facts can lead some facility
owners to have a level of reluctance to invest in this technology.
Fluorescent technology has had the lion's share of the commercial lighting
market for decades, and pricing and performance have been relatively stable
for years. The prevailing industry view is that most of the available
improvements and economies of scale have already been realized for
fluorescent lighting and few, if any, efficiency enhancements or cost
reductions are forthcoming for that technology. The prevailing view of LED
technology is that efficiency will improve and costs will go down as market
share increases and the technology matures. Typical luminous efficacies for
LED luminaires currently range from about 50 to 100 lumens/W, which is
comparable to linear fluorescents. Projections for future efficacy run as high
as 225 lumens/W. Whether that level of performance is actually achievable
remains to be seen.
Lighting power allowances
The allowable lighting power densities of the codes are approximately aligned
with one another. Allowable densities are generally reduced from previous
versions, but not dramatically, as the code-makers have become concerned
about maintaining the quality of the indoor environment at low lighting power
levels. Consequently, most of the improvement in buildings' lighting efficiency
will come from enhanced control requirements, rather than lighting power
density limits. The prescribed levels are roughly as achievable with
fluorescent lighting as with LED, though high-end LED fixtures may provide a
bit better headroom.
Interior lighting controls
All of the codes require some form of automatic shut-off for most interior
lighting, accomplished with occupancy sensing or with time-based controls.
ASHRAE 90.1 and Title 24 require that manual controls be accessible to
occupants for all interior lighting. For most spaces, all the codes require a
"partial-on" function, limiting the lighting power of the first stage to 50% of the
connected lighting power or less. And, all require light-reduction controls that

5. offer at least one control option with substantially reduced lighting power.
ASHRAE 90.1 requires a reduction of 30% to 70% while Title 24 and IECC
require at least 50% reduction. All of the codes require that light-reduction
controls be available to occupants.
Lighting power-reduction controls can be accomplished by dimming all the
luminaires, by switching some luminaires off completely, or by selective
control of a portion of the lamps in each luminaire. The codes require that the
lighting is reasonably uniform when lighting power controls are active.
Lighting power reduction controls provide a slight push toward selection of
LED luminaires. For volumetric applications, these controls can generally be
implemented with fluorescents by judiciously switching lamps in multilamp
fixtures. The uniformity requirement nudges the selection criteria toward LED
devices, especially for single lamp fixtures. It's easy to maintain uniformity by
dimming all the fixtures together. The inherent dimming capability of LED
fixtures makes them an attractive solution for lighting power controls.
IECC offers a path to compliance that includes a requirement that all fixtures
be continuously dimmable, with individual addressability of fixtures where it's
available for the fixture class (C406.4, "Enhanced digital lighting controls").
This path is not strictly required, as it is one of a menu of options for
compliance. An across-the-board requirement for continuous dimming will
strongly push luminaire selection toward LEDs