The synergy of lighting codes and controls
Lighting controls play a key role in meeting energy codes for buildings.
By Michael Jouaneh, LEED AP, Lutron, Coopersburg, Pa.
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Buildings consume the bulk of the world's energy (nearly 40%), so the building industry has been focusing on sustainability, efficiency, and practical energy-saving solutions for both new construction and retrofits.
As the building industry moves (albeit slowly) toward Zero Net Energy—the goal of the Architecture 2030 program —the industry is recognizing that lighting controls play a crucial role in energy conservation. According to the U.S. Dept. of Energy , lighting is, by far, the largest user of electricity in commercial buildings. It consumes 38% of a building's total electricity use—more than space heating, cooling, ventilation, equipment, and computers combined.
Energy codes and standards
The nation's top three building energy codes and standards— California's Title 24 , the International Energy Conservation Code (IECC), and ASHRAE 90.1 —all reflect the importance of using lighting controls to conserve energy. Upcoming versions of these codes and standards go so far as to call out specific lighting control components.
These codes and standards are used by nearly every state as the basis for their local building energy code. They provide the minimum acceptable energy performance requirements for commercial buildings. Here's a brief overview of each:
California Title 24 2008—the California Energy Commission energy efficiency code—officially called “ California Code of Regulations Title 24, Part 6, Energy Efficiency Standards for Residential and Nonresidential Buildings. ” Regarded as the most stringent of all energy codes, Title 24 is something of a “gold standard,” and a reference for a number of subsequent national, state and municipal codes. The 2008 version of the standard will be effective Jan. 1, 2010; all newly constructed or altered buildings in the state must comply with the 2008 standard, depending upon the date of application for a building permit.
IECC 2009—The International Code Council (ICC) has released the 2009 version of the IECC. This energy building code is part of the international “family” of codes produced by the ICC, and was developed through a public hearing process by national experts under the direction of the ICC as a “model” code. Like earlier versions, the 2009 version covers lighting in addition to other energy-using systems, and provides minimum energy-efficiency provisions for both residential and commercial buildings (Note: The IECC references ASHRAE Standard 90.1 as an alternative path of compliance.) According to the Dept. of Energy, the 2009 IECC will produce approximately 15% in energy-efficiency gains compared to the 2006 edition.
ASHRAE 90.1 2010—ASHRAE partners with the Illuminating Engineering Society of North America (IESNA) to produce the 90.1 Standard, which provides the minimum requirements for the energy-efficient design of buildings, excluding low-rise residential buildings. Sometimes referred to as America's primary commercial energy code, ASHRAE Standard 90.1 is published every three years. The next version is scheduled for release in late 2010. The goal is to use 30% less energy compared to the 2004 edition.
Below are some typical mandatory lighting control requirements for commercial buildings:
Area control— Each area enclosed by ceiling-height partitions must have an accessible, independent switching or control device (such as an occupancy/vacancy sensor or manual switch or dimmer) to control the general lighting. Each control device shall be readily accessible and located so the occupants can see the controlled lighting.
Automatic shut-off— All indoor lighting systems must include a separate automatic shut-off control, such as an occupancy/vacancy sensor, time switch, or other auto shut-off device.
Daylighting— An automatic reduction in lighting power in areas where the daylight can help illuminate the space will be required in most areas that are side-lighted (with windows) or top-lighted (with skylights). Typically, an automatic daylighting control device used in conjunction with dimming ballasts to control at least 50% of the general lighting power help meet this requirement.
Demand response— California's Title 24 will require retail buildings with sales floor areas of more than 50,000 sq ft to have demand responsive automatic lighting controls that reduce lighting power consumption by a minimum of 15%. Other buildings types are incentivized to provide this type of control with lighting power density (W/sq ft) allowances.
Exterior lighting— Permanently installed outdoor lighting must be controlled by a photocontrol or astronomical time switch that automatically turns off the lighting during daylight hours.
Multilevel lighting controls— Most spaces must have the ability to reduce lighting power by either continuous dimming, stepped dimming, or stepped switching while maintaining a reasonably uniform level of illuminance throughout the controlled space. Typically, the capability to reduce lighting power by 50% (in addition to full-off) for general lighting of an enclosed space complies with this requirement. California's Title 24 calls for lighting controls in most spaces to have at least one step between 30% and 70% of design lighting power, and allow lights to be turned off manually.
Jouaneh is marketing manager with Lutron. His primary focus is on energy conservation and sustainability, where he emphasizes using daylighting and other light control strategies to save energy and meet codes while improving the comfort and productivity of people in the space.
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