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Green Technology and Existing Buildings

In the early ‘80s, a few designers started paying attention to sustainable architecture. Twenty years later, green buildings are mainstream. Major conferences are devoting significant time to the subject. Since 2000, “building teams for more than 1,000 projects have taken the first step toward LEED certification . . these projects represent 7 percent of all new commercial construction” reports Engineering News-Record.

It is easier to think about green buildings when you have a blank piece of paper to start with. The choice of systems and materials is wide open. But how can existing buildings become greener? The U.S. Green Buildings Council (USGBC) has developed the LEED (Leadership in Energy & Environmental Design) rating system for existing buildings. Already, 90 projects are involved in a pilot program. A draft of the rating system was released for public comment on February 23. The system is summarized below, along with some suggestions for implementation.

A Definition of Green

Green building, or sustainable design, is easy to understand as a concept. As a measurable standard, however, it is much more difficult. It embodies use of the site, the materials employed, the systems designed and installed, and how the facility is maintained and operated. In any integrated system, there are always tradeoffs. Evaluating the benefits of one approach over another becomes extremely complicated. Nevertheless, it is important to begin the journey.

The issues for existing buildings identified by the USGBC include cleaning and maintenance, indoor air quality, energy efficiency, water efficiency, recycling, exterior maintenance, and system upgrades. The pilot program addresses these categories under the same rating categories as new construction, but sometimes with different point totals. The categories and their relative emphasis in term of percentage points available are:

  • Sustainable Sites – 23 %
  • Water Efficiency – 7 %
  • Energy and Atmosphere – 31 %
  • Material and Resources – 14 %
  • Indoor Environmental Quality – 25 %

Points are also given for innovation and having accredited professionals on staff. The USGBC has guidelines for each of these categories. The guidelines are summarized briefly below.

Sustainable Sites

There is a limited amount that can be done with an existing site since development has already occurred. That in itself may be the first criterion – don’t build new if existing facilities work. Other approaches include policies and procedures to manage site sedimentation and erosion such as fencing, traps, and plantings. Encourage environmentally friendly forms of transportation such as bicycling and links to public transportation. Reduce site disturbance by minimizing paved areas and restoring natural greenspaces. Reduce stormwater runoff and install treatment systems for the effluent that remains. Reduce heat islands through plantings, water features, colors and materials, and design characteristics. Limit light pollution and the impact on nocturnal environments.

Water Efficiency

Water usage has become a critical concern. Use recycled water for irrigation. Production of wastewater should be minimized. Consumption of potable water should be reduced. Low flow devices are already part of many codes. Re-use of wastewater and rainwater, filtering systems, and other approaches are all important.

Energy and Atmosphere

Data now exists for comparing the energy consumption of buildings of different types. The Commercial Buildings Energy Consumption Survey (CBECS) is a data base of 5,000 buildings of various sizes and uses. The most recent data (1999) can be found at This information can be used to establish goals for your facility. Procedures for minimizing CFC-based refrigerant leakage should be employed. Energy reducing technologies abound including conservation measures, high-efficiency equipment, solar strategies, daylighting strategies, green operating procedures, and innovative air-flow and recirculation systems. Geothermal energy, other renewable sources of energy and co-generation can be considered. Maintenance – especially preventive maintenance – is also an important component of sustainability.

Material and Resources

Material selection is obviously important, but very complicated to evaluate. The factors to determine whether a product is appropriately green include the environmental effects of production, shipping, application, use, and ultimately, disposal – in other words the life cycle impact, not just the immediate benefit needs to be considered. Use of recycled and reused materials scores high here, as do components that are easy to recycle. So do materials produced relatively close to the building site.

Indoor Environmental Quality

With buildings being buttoned up more tightly and more synthetic materials being used, indoor air quality has become a major concern. Some manufacturers are now providing data about health-related concerns with their products. The better managers we have seen maintain an active monitoring program for pollutants such as smoke, CO2, and outgassing chemicals and ambient conditions for temperature, light, and ventilation. Appropriate action also extends to the materials and methods used for cleaning and maintenance. Management must also be vigorous in addressing areas of concern. For example, current concerns about mold always originate with a moisture problem. Water intrusion must be handled immediately in all cases. Water leaks also contribute to the growth of bacteria such as Legionella.

Innovation and Professional Accreditation

Maintaining a sustainable environment is not a one-time decision but an ongoing commitment. The professionals who manage your facility must be educated and trained in appropriate technologies, and there must be an ongoing effort to consider green alternatives during routine maintenance (filters, pest control, purchasing) as well as remodeling. The USGBC offers an exam and Accredited Professional designation.

What’s in It for Me and What Do I Do Next? 

Already 87 buildings totaling almost 27 million square feet are undergoing LEED-EB pilot certification. All GSA major renovation projects must now be LEED certified. Companies that want to demonstrate leadership are signing up to become LEED certified. Compliance, is more than a good thing to do; it can contribute to reduced operating costs and improved productivity. Copies of LEED for Existing Buildings are available from the U.S. Green Building Council, either on-line at or at 1015 18th Street, NW, Suite 805, Washington, DC 20036, 202-828-7422. If you are interested in evaluating your building(s) or implementing green technologies, please contact us at the address below.

Volume 15, Number 1

March 2004

Copyright © 2004

The Engineering Advisor is intended to enhance your knowledge of technical issues relating to buildings.  For additional information on any subject, please feel free to call us.  Our commitment is to provide you with timely, accurate information.