Lighting & LEED

By Craig DiLouie, Lighting Controls Association

Updated August 2005

Commercial and residential buildings in the United States consume about two-thirds of domestic electric generation, more than one-third of domestic energy production, more than one-tenth of potable water, and 40 percent (or 3 billion tons) of raw materials globally, while producing about one-third of total greenhouse gas emissions and 136 million tons of construction and demolition waste each year.

This model is not sustainable. America’s infrastructure depends on an enormous amount of resources, and yet these resources are in finite supply and are steadily diminishing. As a result, a number of leading architects have committed to sustainable or “green” design practices. The U.S. Green Building Council’s Leadership in Energy & Environmental Design (LEED) has become the driving force behind this movement.

LEED defines green design, promotes green design practices, and rewards organizations that adopt green design. LEED projects are certified according to the number of points achieved, indicating how green the building is: Certified (26-32), Silver (33-38), Gold (39-51) and Platinum (52-69).

Lighting is related to achieving at least 8 points and as many as 22 points in these sections: Sustainable Sites, Energy & Atmosphere, Indoor Environmental Quality, and potentially Innovation & Design Process.

Sustainable Sites
Sustainable Sites represents 22 percent of the total possible LEED points and intersects with lighting in Credit 8, Light Pollution Reduction (1 point). LEED requires the architect to “eliminate light trespass from the building and site, improve night sky access and reduce development impact on nocturnal environments.”

To gain this point, the architect must meet or provide lower outdoor light levels than those recommended by IESNA RP-33-99: Lighting for Exterior Environments; ensure that the maximum candela value for all indoor lighting must fall within the building (not through the windows); ensure that the maximum candela value for all outdoor lighting must fall within the property; and specify shielding for any fixture within a distance of 2.5 times its mounting height from the property boundary, so that no light spills over the boundary. In addition, all fixtures that produce more than 1,000 initial lumens must be shielded, and all fixtures that produce more than 3,500 initial lumens must meet the Full Cutoff IES classification so no light is emitted skyward.

Energy & Atmosphere
Energy & Atmosphere represents 27 percent of the total possible LEED points; lighting plays a significant role in this section. Before earning any points, the architect must meet two prerequisites. First, all building systems such as lighting control systems must be properly commissioned. Second, the building’s electrical systems design must comply with the ASHRAE/IESNA 90.1-1999 model energy code or the local code if more stringent. This is already required in most states. The Department of Energy mandated Standard 90.1-1999 as the minimum design and construction standard for commercial buildings throughout the United States as of July 15, 2004. To date, 32 states have put in place a code at least as stringent as Standard 90.1-1999 (some have adopted stricter codes), while 18 states still have a weaker code or no code at all.

Standard 90.1-1999’s lighting requirements are already twice as restrictive as the 1989 standard. For example, the maximum power allowance is 1.3W/sq.ft. for offices, 1.5W/sq.ft. for schools, and 1.9W/sq.ft. for retail buildings. Standard 90.1-1999 also mandates automatic shut-off controls.

In Credit 1, between 1 and 10 LEED points are granted for exceeding Standard 90.1-1999 (or local code) on a scale that rewards maximum energy efficiency. Credit is given based on the whole building’s energy use, not just the lighting.

“The growing popularity of newer technologies that involves such strategies as the dimming of HID fixtures and the use of addressable fluorescent lighting work towards a fully integrated building and support LEED compliance,” says Stuart Berjansky, Senior Product Manager, Controllable Lighting for Advance Transformer Company.

Architects may also achieve additional points by meeting the requirements under “Credit 3: Additional Commissioning” (1 point) and “Credit 5: Measurement & Verification” (1 point). An independent commissioning authority must review the design and construction documents, commission the systems, and train building operators in system use. The latter requires verification of building performance over time either through site visits or automatic metering.

Indoor Environmental Quality
Indoor Environmental Quality represents 23 percent of the total possible LEED points. Lighting intersects with this section in two places—controllability of systems and daylighting.

Credits 6.1: Controllability of Systems: Perimeter Spaces (1 point) requires that the design “provide a high level of thermal, ventilation and lighting system control by individual occupants or specific groups in multi-occupant spaces (i.e., classrooms or conference areas) to promote the productivity, comfort and well-being of building occupants.” Studies indicate that giving personal control of light levels and thermal comfort to workers can improve their satisfaction. The design should provide at least one lighting control zone per 200 square feet, within 15 feet of the perimeter wall.

Credits 6.2: Controllability of Systems: Non-Perimeter Spaces (1 point) requires the same benefits be provided for occupants in the building’s non-perimeter spaces. The design should provide individual lighting controls for at least 50 percent of occupants in regularly occupied non-perimeter spaces.

Credit 8.1: Daylight and Views: Daylight 75% of Spaces (1 point) requires that 75 percent of all critical visual task occupied space must achieve a daylight factor of 2 percent, and occupants in 90 percent of regularly occupied spaces must have direct line of sight to vision glazing. Studies indicate that giving occupants access to daylight and access to a view can improve their satisfaction.

“Incorporate daylighting controls when ample daylight is available,” says Dorene Maniccia, LC, LEED v.2 AP, Manager, Market Segment Development for The Watt Stopper. “Utilize the expertise of a daylighting or lighting consultant to predict daylight illuminance and distribution, and its effect on lighting quality.”

“Daylight harvesting is an increasingly popular strategy,” says Berjansky. “It falls into many different areas of the LEED rating system, such as Daylight & Views and Innovation & Design.”

Innovation & Design
Innovation & Design enables architects with innovative new design approaches to earn from 1 to 4 additional points. “This credit offers opportunities for unique ideas not covered in LEED,” says Maniccia. “We’ve seen occupancy-based plug load controls and DALI control strategies be recognized by the LEED criteria in this category. Because plug loads are exempt from the energy code, and are not addressed by LEED, control strategies that reduce plug loads can significantly help to reduce energy use.”

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