LEED-EB Extends Green Rating System to Existing Buildings

by Craig DiLouie, Lighting Controls Association

Posted October 2007

Many corporations have traditionally resisted the idea of “green” buildings for a variety of reasons. Some think it’s a radical idea, others an unnecessary cost, and still others a fiction created by environmental extremists rather than an investment that can produce tangible economic and environmental benefits.

There is evidence that this view is changing. A 2007 Johnson Controls study, sponsored by the International Facility Management Association (IFMA), found that 62% of surveyed business leaders were paying more attention to energy efficiency than they were just a year ago, and that 67% had invested in energy-efficient lighting. About one-half (52%) say it was entirely, mostly or somewhat related to cost savings; 12% say environmental responsibility was somewhat more or mostly the primary motivator; and 35% say the two factors were equal motivators.

Some corporations embrace the concept of sustainability but do not put it into practice; they tend to make announcements that are typically denounced as “greenwash” by environmentalists. But it’s hard to criticize when for so long few could even agree on a definition of sustainability. What is a “green building,” anyway? Enter the U.S. Green Building Council (USGBC), which launched the Leadership in Energy & Environmental Design (LEED) green rating system for new construction (LEED-NC), existing buildings (LEED-EB) and vertical building markets.

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 based on how green the building is—Certified (26-32), Silver (33-38), Gold (39-51) and Platinum (52-69).

In new construction, sustainability has entered the mainstream. In 2003, LEED-NC registered projects were valued at about $5.5 billion and represented 3% of all projects in the U.S. construction market and 7% of floorspace. By 2006, the total estimated value of project was $7.7 billion. USGBC predicts that by 2010, there will be 100,000 LEED-certified commercial buildings and 1 million certified homes. By 2020, there will be 1 million LEED-certified commercial buildings and 10 million certified homes.

The LEED rating system for existing buildings addresses cleaning and maintenance issues, indoor air quality, energy and water efficiency, recycling and systems upgrades to meet green building energy, water, air quality and lighting performance standards. In terms of lighting, LEED-EB addresses 1) light pollution reduction, 2) energy efficiency, 3) performance-related issues such as commissioning and sub-metering, 4) mercury content in lamps, and 5) controllability of lighting systems. As of March 2006, there were 137 registered projects, and as of June 2006, 30 certified projects.

light pollution reduction

LEED-EB Sustainable Sites, Credit 7, worth 1 LEED point, requires control of nighttime lighting to minimize skyglow (light emitted up into the sky) and light trespass (light emitted onto neighboring properties). Even if the lighting management company does not provide the installation services, there is a significant maintenance component.

There are two options to minimize uplight. First, all fixtures using a lamp rated 50W and larger must be shielded to prevent uplight. Second, the sum of all emitted uplight must be 5% or less than the total light emitted by the outdoor fixtures.

There are also two options for minimizing light trespass. First, one can demonstrate that the light levels at the site perimeter do not increase by more than 10% when all the project lights are turned on (indoor and outdoor). Second, the maximum candela value for all indoor fixtures must not exit the building, the maximum candela value for outdoor fixtures must fall within the property, and all fixtures within 2.5 mounting heights of the property line may emit no more then 5% of their light output off the property.

These requirements can be accomplished by either replacing existing fixtures or simply adding shielding. Whichever options are chosen, the lighting system must be inspected quarterly, with the results recorded, to ensure that the features are being maintained.

energy efficiency

LEED-EB Energy & Atmosphere, Prerequisite 2, requires the building to demonstrate an EPA Energy Star rating of at least 60 using the EPA’s Portfolio Manager tool for covered building types. For non-covered types, the building must demonstrate that it has energy performance equivalent to at least 60 as calculated using the alternative method described in the LEED-EB Reference Guide. EA Credit 1 awards 1-10 points for achieving a higher Energy Star rating on a sliding scale (see Table 1).

Table 1. LEED-EB EA points assigned based on EPA Energy Star rating.

As of June 2007, all LEED-certified projects, with the exception of LEED for Homes and LEED for Neighborhood Development projects, must achieve at least 2 “Optimize Energy Performance” points, which is expected to improve efficiency in existing buildings by 7%; at the time of writing, the Green Building Council had developed, but not yet released, a new prescriptive compliance path to achieve these points (see the LEED website for more information).

There are numerous options for achieving LEED points, including high-performance T8 lamps, low-output and higher-efficiency-type electronic ballasts, occupancy sensors, scheduling, daylight harvesting dimming or switching, low-wattage metal halide sources and others available from a broad range of manufacturers. The ability to maximize LEED points will depend on the existing system, although even basic-grade T8 systems can be upgraded with new high-performance systems.

For more information about the Energy Star building rating system, click here.

mercury content in lamps

LEED-EB Materials & Resources, Prerequisite 2, requires that the building and grounds maintain the content of mercury-containing lamps <100 picograms per lumen-hour, as a weighted average. MR Credit 1 awards 1 LEED point for maintaining <80 picograms/lumen-hour as a weighted average for all mercury-containing lamps.

Highly efficient lamps offered by the major manufacturers typically utilize small quantities of mercury.

Also note that not every lamp used has to be below the 100 picogram/lumen-hour limitation; only the weighted average of lamps in use must be below that level. Any lamp can be used as long as there are enough lamps below the limit to average out the lamps above the limit. To help calculate picograms/lumen-hour for selected lamps, see online calculators from OSRAM SYLVANIA here and Philips Lighting here.

controllability of lighting systems

LEED-EB Environmental Quality, Credit 6.1 awards 1 LEED point for providing a high level of lighting system control for individual users or groups of users in multi-occupant spaces such as classrooms. The goal, says LEED, is to “promote the productivity, comfort and well-being of building occupants.”

Providing occupants with the ability to switch or dim their local lighting, as shown here after a retrofit of the IEEE Command Center with OSRAM SYLVANIA's DALI-based digital dimming ballasts, can increase worker satisfaction and save energy while helping building owners earn 1 LEED point for controllability of lighting systems.

At least 50% of all building occupants must be given the ability to adjust task light levels to suit their needs and preferences individually or, if sharing a multi-occupied space or workgroup area, as a group.

Options include simple switching strategies such as undercabinet task lights to dimming strategies such as multi-scene dimmers and individual user dimming controls. Occupants should be trained to use the controls.

other opportunities and requirements

Daylighting and providing views for occupants are encouraged by LEED-EB, but can be difficult to implement in existing buildings. Buildings must be commissioned—in any cases retro-commissioned, requiring identifying components that do not work according to the specs, repairing or replacing them, and retesting to verify performance according to the specs. Credits are provided for monitoring energy performance and providing staff education. In addition, LEED is heavily focused on documentation, requiring a certain amount of paperwork. It may be useful to become a LEED-Accredited Professional, marking one as an expert on the LEED compliance process.

To learn more about the LEED-EB program, click here.

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