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February 19, 2009

What owners need to know about LEED

  • There are different paths to certification, but the process requires a serious — and early — commitment.
  • By MICHELLE ROSENBERGER and NANCY HENDERSON
    ArchEcology

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    Rosenberger

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    Henderson

    It’s official. Sustainability is not a trend or a fad. Green building has quickly become an obvious economic necessity.

    For the building industry that means programs like LEED are here to stay. LEED has become the green building program of choice because its rigor and its nationally based focus on best practices makes it credible in the marketplace.

    As green buildings have increasingly demonstrated competitive advantage by attracting preferred buyers and tenants, yielding higher square footage returns and lower annual utility bills, more and more projects are pursuing LEED certification. If you are considering LEED for your project, there are some things you should know to manage your pursuit successfully.

    Paths to compliance

    LEED requires interpretation. Every project has a unique combination of site, program, region and material characteristics that may or may not lend themselves easily to LEED requirements.

    Concrete and steel building types may easily reach regional and recycled content material thresholds, while wood-frame construction may struggle to realize recycled content points. Some regions have more access to recycling facilities for construction waste than others. Some programs can take advantage of operable windows and natural daylight and some cannot.

    Photo by Sky-Pix, courtesy of Legacy Partners
    Legacy Partners used an energy model to weigh its fuel, glazing and insulation options at the Legacy Corporate Center Redmond. The project was designed to achieve a LEED silver rating.

    As a result, the U.S. Green Building Council offers different rating systems and alternate compliance paths. In Washington where we are fortunate to enjoy stringent stormwater management, energy efficiency, ventilation and indoor air-quality requirements, meeting local codes may be enough to satisfy certain LEED credits.

    The location of your project site and the regulatory requirements of its region are essential to evaluating the feasibility of LEED credits and the effectiveness of sustainable strategies.

    LEED incorporates numerous existing national standards into its requirements. As a method to avoid reinventing the wheel, it makes good sense and leverages the efforts of others. However, these adopted standards don’t fit each region or each project like a glove.

    ASHRAE standards, for example, used to establish LEED’s thermal comfort baselines, tend to favor highly sophisticated, climate-controlled spaces rather than the rudimentary systems the temperate Pacific Northwest encourages.

    Favoring design

    LEED can be choosy about which parts of any given standard it is referencing.

    For example, SCAQMD (South Coast Air Quality Management District) rules used to establish volatile organic compound limits for adhesives and paints were created to address overall air quality in California. They restrict both interior and exterior products and grow increasingly more stringent over time.

    LEED currently incorporates only the interior rules, and limits vary depending on the version of the rating system being used for the project.

    LEED rewards early intervention. In addition to the many benefits of having everyone on the project team working together toward a jointly held goal, the practical reality of the rating system is that design credits constitute almost two-thirds of the available credits.

    Design credits reflect decisions made during the course of the design process and are typically documented with design narratives, plans and calculations. The large ratio of design credits means that the earlier in the design process the decision is made to pursue LEED certification the more flexibility the project will have in pursuing points.

    Construction credits by contrast typically concern construction practices and material requirements that are proven through product data submittals, construction documentation and on-site verification. Once construction begins, changes to products or practices are increasingly costly and less feasible.

    Cost considerations

    LEED adds measurable value, but it costs money. That is not to say that you must expect your project budget to increase overall, but there will be additional scope and fees to factor into your decision-making early in the design and construction process so that appropriate trade-offs can be made.

    As with any investment, initial costs have to be carefully weighed against long- and short-term benefits to establish the sustainable measures right for your project.

    When people think of added costs, they often think in terms of premiums for materials and equipment. That is certainly valid when considering things like Forest Stewardship Council wood products or high-efficiency HVAC or lighting fixtures or other product substitutions.

    But perhaps even more significantly than these discrete costs, pursuing LEED may require added scope and new responsibilities. Two areas in particular frequently cause confusion and are worth further exploration.

    Commissioning: Of the seven mandatory prerequisites universal to the LEED rating systems, fundamental commissioning is one of the few with a direct impact to the bottom line, and often to the consultant team as well.

    “Commissioning” is a term that up until recently was understood by mechanical engineers to mean the basic equipment checks and testing and balancing done by installation subcontractors to satisfy Washington Energy Code requirements.

    However, LEED has expanded the scope of work at the fundamental level to include a commissioning authority and several other variations on what was once a commonly understood theme.

    In other words, you can satisfy Washington’s requirements by doing LEED-style commissioning, but you cannot comply with LEED by simply satisfying Washington Energy Code requirements.

    At the enhanced commissioning level, the scope of work expands even further. These distinctions are important to make with the design team early on.

    Whole-building energy modeling: Before turning to equipment efficiency, demand-reduction measures are the first line of defense.

    The building envelope, for example, plays a major role in heat loss and gain. Thermal windows and overall percentages of glazing, insulation values, daylighting and skylights to mitigate lighting needs are all important considerations.

    Efficient lighting fixtures and reduced lighting power densities can lower energy use directly and indirectly by lessening cooling requirements. As a result, the overall energy use of your building involves much more than just mechanical systems.

    Whole-building energy models that can incorporate the benefits of envelope and lighting improvements will typically achieve better energy use reduction percentages than those that only employ equipment efficiency measures. These higher percentages translate to more potential LEED points and to increased utility company incentives.

    Embracing the spirit

    LEED certification is a process not merely an outcome.

    Each project represents a unique application of LEED standards, adds to the growing body of sustainable design knowledge and informs the next version of LEED rating systems. And in fact, just as we are becoming completely conversant with the current systems, the much-heralded LEED 2009 version is expected in March.

    Be wary of the temptation to undertake the process without committing to obtaining the certification.

    Those that say they have designed and constructed their project to meet LEED standards but simply chose not to worry about a plaque on the wall almost certainly can’t get one. The commitment to obtaining LEED certification holds the team’s feet to the fire when the inevitable hard choices present themselves along the way.

    LEED certification will only retain its value in the marketplace so long as those that pursue it embrace the spirit and not just the letter of its requirements and those that review their results do the same. After all, the points are not the point.


    Michelle Rosenberger and Nancy Henderson are partners in ArchEcology, a sustainable design consulting firm in Seattle.



     


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