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For techno types and gadget geeks, the moment a new Playstation, iPhone or Windows system hits the market, it’s already old news. Their focus immediately turns to the next version. A similar phenomenon is taking shape with the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system. Even though Version 3 was just unveiled in April, the building/design community—including lighting experts—already have visions of the next version dancing in their heads. That may be due, in part, to the fact that LEED 2009 (i.e., v3) was tweaked only at the margins. According to the USGBC, v3 “is not a tear down and rebuild of the LEED that exists,” but rather it “builds on the fundamental structure and familiarity of the existing system.” Indeed, the LEED building categories remain the same (i.e., New Construction, Core and Shell, Schools, Existing Buildings: Operations and Maintenance, and Commercial Interiors) and the framework for earning points (i.e., Sustainable Sites, Water Efficiency, Energy and Atmosphere, etc.) is virtually identical. While the credits are all intact, some are worth different amounts. As a result, LEED v3 now operates on a 100-point scale.
Lighting professionals, however, have more ambitious plans for the next go-around. Both the IES and the IALD have formed task forces that will make recommendations to the USGBC on how lighting should be addressed in the future. We queried four professionals serving on one or both of those task forces (Nancy Clanton, Clanton & Associates; Chad Groshart, Atelier Ten; Richard Heinisch, Acuity Brands Lighting; and Giulio Pedota, Schuler Shook) for their thoughts on the effectiveness of LEED to date and what LEED v4 should look like when it takes effect in 2011. Not surprisingly, there is both consensus and disagreement in their replies to the following questions.
—Paul Tarricone
1. What’s your overall assessment of the way lighting has traditionally been treated within the LEED points system?
Chad Groshart: The LEED system is designed to contribute to healthier environments, as well as save energy. It does some useful things in its consideration of daylight and views for occupants by addressing a need for glare control and encouraging the placement of densely occupied areas where there is access to daylight.
LEED has treated electric lighting like a building system similar to HVAC. As designers, we face great pressure from owners and clients to push LPDs down on LEED jobs. The result is that we are starting to see under-lighted, flat buildings or spaces with hopelessly bright (efficient!) fixtures that do very well on the LEED scorecard, but provide poor visual environments.
Giulio Pedota: It’s been a good starting point towards being more environmentally friendly and ensuring quality lighting design; however, the lighting credits could be improved. They need to be more realistic (e.g., meeting exterior requirements for Sustainable Sites-Credit 8 “Light Pollution Reduction” in highly illuminated cities like Chicago is extremely difficult); they need to address lighting quality as it relates to human comfort (e.g., getting extra points for glare reduction in Environmental Quality “Daylight & Views”); and lighting should be included in the Materials & Resources category, which could offer vast opportunities for improving the environmental impact of lighting.
Nancy Clanton: In general, I am satisfied with LEED Environmental Quality and Energy & Atmosphere credits. I am thrilled that there is a Sustainable Sites credit which recognizes light pollution—even though this credit is “broken.” Unfortunately, it uses a percentage of uplight vs. downlight (which may encourage more downlight if there is a considerable amount of uplight), a single watts-per-square-ft value for all lighting zones and illuminance-level distances from the property line that are not based on any published standard. Hopefully, this credit will be changed to fall in line with the Model Lighting Ordinance, such as achieving one lighting zone stricter than the lighting zone where the project is located.
All of these credits address issues that no other document does, such as providing daylight, views and individual control over areas. In the large scheme of things, it’s huge to give “points” or credits for things that are important but difficult to quantify.
2. Is energy usage (kWh) a more appropriate metric than watts per sq ft?
Richard Heinisch: A cautious yes. While a reduction in energy use is the obvious goal, there is a timing issue here. A LEED project is approved based on a design at a single point in time. But with energy use as the metric, the actual energy savings are based on operating hours (be that from an operating schedule or the use of controls) and the hope that these will remain the same after occupancy. These projected savings can begin to evaporate as controls are overridden or not maintained.
Pedota: Absolutely. The “actual” operation of a lighting system on an hourly basis is the most accurate measurement of energy consumption. While the “connected load” used in the current system does provide an indication of the potential energy usage of a particular space, it is far more realistic to measure the actual energy consumption—in kW per hour—to achieve accurate readings. Europe is utilizing the kW per hour model; so should LEED and ASHRAE.
Clanton: Absolutely! This would require that all submittals be modeled using the whole building energy model versus the simpler prescriptive method of watts per sq ft. Lighting controls would play a major role in reducing energy versus relying on reducing the power density. It would also give the designer more freedom in how to reduce energy consumption.
In going to kWh, the energy codes would need to be changed to address energy usage instead of only predicting connected power. It would require better integration with other energy consumption items. Also, regulation may change from predicted modeling to actual energy consumption reporting. Redirecting the codes to energy use would put a greater emphasis on lighting controls and daylighting integration. Since modeling would still be an important design tool, assumptions such as occupancy data would need to updated and refined.
Groshart: USGBC relies on existing standards to frame the LEED program. The upside is that this has kept them from having to reinvent the wheel on many aspects of building system technology. The downside is that when LEED rewards benchmarks far below the threshold of an already efficient standard like ASHRAE/IESNA 90.1, the visual environment suffers. As a voting member of the 90.1 lighting subcommittee, I know that the standards are crafted around a reasonable amount of power for the tasks performed. ASHRAE is constantly looking to save energy and tweak the code to be as efficient as it can be. Simply lopping off 15, 25 or 35 percent of the connected load, to earn one, two or three LEED credits, is risky even with careful design.
A true energy standard that looks at kilowatt hours would be the most accurate metric of how the entire lighting system (luminaires and controls) is performing. There are challenges with how this would be measured and enforced. However, LEED already offers points for “measurement and verification” (submetering) and “enhanced commissioning” to ensure the building is performing as designed. This offers an excellent opportunity to look at lighting energy (power over time) not just power and not have to reference LPD.
3. Should lighting points be “packaged” into one group on the LEED scorecard?
Pedota: It would be advantageous to organize all the lighting credits under one category, very much like “Water Efficiency,” as long as the synergies between lighting and other disciplines are not lost in the process.
Heinisch: I would say no. While the current system of categories within LEED is imperfect, it provides a reasonable structure on how to think about designing and constructing a sustainable building. What would be helpful as an alternative would be a single Lighting Technical Advisory Group (TAG) instead of having lighting advisors integrated with the various category-based TAGs. This would allow the various individuals from the lighting industry serving on the individual TAGs to work together to better integrate lighting into LEED as a whole. Instead of getting the limited viewpoint of one or two members on any one TAG, grouping them together into a single Lighting TAG would allow for a more diverse and synergistic development of credits.
Groshart: The benefit of a single package of lighting points would be that architects and the USGBC would start to consider the complex and multidimensional nature of lighting in environmental design. Currently the credits have no interrelation except for the Post-it notes that live in the LEED manual on a lighting designer’s desk. Putting them all together would force the people drafting the credits to see the connection.
Clanton: LEED 2011 will head in a new direction by assigning weighted points to each category. Weighting factors may include carbon reduction, triple bottom line (profit, people and planet) and social equity. An example of this may be daylighting. If the electric lighting is reduced in response to daylighting, then carbon is reduced. If the daylighting also uses view windows, then social equity is higher. If the return on investment is excellent with these strategies, then profit is increased. What we need is more research on the “value” of daylight, views and lighting quality to people (higher productivity, better learning environments, etc.). This value needs to be built into an economic model for profit predictions.
Lighting should not be a single package, but integrated into environmental quality and reduction in energy. Developing lighting quality benefits that go way beyond energy reduction should be a top priority.
4. Should LEED attempt to measure lighting quality?
Heinisch: Yes. A lighting system with poor quality cannot be considered “sustainable.” I recently served on an IES task force where our goal was to generate a lighting quality rating system. Our first draft included a system with 19 individual parameters including:
• Economic and environmental issues such as the appropriate use of daylight harvesting and other controls, lighting load and commissioning;
• Human needs issues such as daylight integration, color appearance and illuminance levels;
• Architectural issues such as architectural appropriateness.
Such a system could be integrated into LEED but would probably require a different weighting mechanism to better reflect the specific goals of LEED (i.e., the goals of the IES in developing a lighting quality rating system may not exactly align with the goals of the USGBC and LEED). For example, USGBC may assign more weight to life-cycle issues than was done on the recent IES task force. Such integration would probably require a complete revision of the lighting-based prerequisites/credits within LEED.
Pedota: Absolutely. The current lighting credits emphasize light pollution, energy performance, controls and daylight, most of which can contribute to lighting quality to some degree. However, the full capacity of quality lighting, to the extent that lighting designers can achieve it, is not fully addressed in the current version of LEED; this is LEED’s next frontier.
To achieve this, LEED scoring needs to recognize strategies that would:
• Reduce glare in interior and exterior applications;
• Provide adequate illumination levels and contrast ratios for certain applications;
• Develop a three-dimensional illumination computer model to improve the quality of the design;
• Achieve specific surface reflectances for specific applications;
• Compensate where ASHRAE/IESNA 90.1 fails to address specific conditions (e.g., additional energy allowances for spaces with high ceilings and elderly people).
Groshart: LEED succeeds as a quantitative benchmarking system. Lighting quality is a complex issue that many lighting groups have struggled to define. LEED offers a single point for using a LEED Accredited Professional on the project. It could offer a point under “lighting quality” for any project that hires a professional member of the IALD to design the visual environment.
Clanton: I wish we could “measure” lighting quality. In order for lighting quality to become part of the LEED rating system, we (lighting designers) would need to develop a rating system that can be understood and documented by everyone submitting LEED credit applications. We also need to develop weighting factors for lighting quality: More carbon reduction? Higher profits? More social equity? If a lighting quality credit is developed, it will need thoughtful due diligence regarding its legitimacy.
One idea may be to provide education on what quality lighting design entails. Then mandate post-occupancy evaluations from occupants to see if the lighting quality was achieved and satisfaction has occurred. This would relieve us from defining quality.
August 09
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