Going Beyond LEED
July 01, 2007
Appeared in Urban Land
Guidelines under the Leadership in Energy and Environmental Design (LEED) program are employed so regularly today that the U.S. Green Building Council (USGBC) and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) are currently writing environmental standards capable of being adopted into the International Building Code. With green building gaining such wide acceptance, what is the next step in green evolution?
The collective architectural and engineering community needs to define the next level of green buildings and what they will stand for. Currently, there is a cerebral separation between architects and engineers—a situation for which both are to blame. Many architects are attempting to design green buildings in isolation, while their engineering partners are satisfied with filling in the blanks with whatever sustainable systems can fit the space.
Going beyond LEED will bring engineers and architects together in conceiving sustainable solutions that blur their disciplines. Neither the architect nor the engineer can be held solely responsible for tomorrow’s green design. Instead, they must begin engineering the architecture—integrating aesthetics with systems design to create a higher-performance facility.
In the words of sustainable design leader William McDonough, founder of Charlottesville, Virginia–based William McDonough + Partners, “Being less bad is not being good.”
Take the Hummer and the Toyota Prius as metaphors. Today’s typical energy hog of a building is the equivalent of a Hummer. From a sustainabililty perspective, it is poorly designed and clad with a building envelope and materials that would leave any Earth-hugger crying. It is designed solely according to the owner’s specifications, with disregard for the environment and surrounding climate. But in an effort to illustrate some “environmental consciousness”—that is, “being less bad”—designers often slap a sexy renewable technology like photovoltaics or a wind turbine on top and call the buildng “green.”
On the other hand, a building with truly integrated design is the equivalent of a Prius. Its systems and materials are specified to complement the surrounding environment. With no economically unjustified technologies or materials, it incorporates simple green design throughout.
A building like the Hummer will harm the environment, while a Prius-type facility will serve the Earth for years to come.
New buildings need to be engineered and designed like the Prius. The next generation of green buildings must be more climate responsive in order for architects and engineers to qualify as climate-responsible designers. Architects and engineers must analyze the regional climate and general environment of every job site during the early planning stages to determine how the facility to be built there can be designed to both complement the site and meet the project’s demands.
Climate-responsive design involves the careful configuration of building form and internal building systems to take advantage of the local climate’s attributes and minimize the impact of its less-desirable elements.
Consider two simple climate-responsive dwellings: a central Arctic igloo and an African thatch palapa. Each structure is designed with regional materials to respond appropriately to the dissimilar climates; no one would make the mistake of building one dwelling in the other’s climate. However, architects and engineers are satisfied with building essentially the same structure with identical form, materials, and technology no matter where it is to be built.
Once the site has been chosen and a climate analysis completed, the next element for architects and engineers to consider is the building envelope.
Traditionally, facade design has been regarded solely as the architect’s domain, but because it is the cornerstone of climate-responsive design and indoor environmental quality, the planning phase of an integrated facility will involve the engineer as well.
The climate and environmental analysis will help designers evaluate options based on the building’s massing and orientation. Then materials selection and daylight and solar control can be optimized.
The goal is for engineers to help the architects allow as much natural light and ventilation as possible into the building while also minimizing solar gain and the adverse effects of direct sunlight and glare. Three-dimensional building simulation tools aid this effort by illustrating the benefits of various daylighting and natural ventilation design options.
Up-and-coming facade technology will also enhance sustainable exteriors. High-performance glazing, integrated exterior shading systems, and specialized window treatments that direct and control daylight are now available and more cost-effective than ever. Advances in glass coatings and electrochromic windows will also continue to improve the ratio of light to solar gain.
A facility’s mechanical and electrical (M&E) systems are the next major component that needs to be addressed. Designed to handle a building’s periods of highest peak demand, M&E systems are created with “worst-case” engineering to perform during the hottest 35 hours per year. Although this capability is crucial, the climate-responsible building will also reduce M&E system demands and loads whenever possible so the system works most efficiently during periods of low or partial loads. For these times, engineers can specify additional, alternative M&E systems, including daylight-harvesting controls, displacement ventilation, under-floor air distribution, radiant heating and cooling, chilled beams, mixed-mode systems, and natural ventilation to take greatest advantage of the energy savings and indoor environmental quality potential available.
A climate-responsible design team also makes better long-term economic decisions. For example, sustainable designers use the 2-20-200 rule to justify the need for improved integrated design in many owner-occupied commercial projects. Here is how it works:
On average, a building owner spends about $2 per square foot ($21.50 per sq m) in energy costs each year. The cost of constructing this typical building, amortized over 25 years, comes to $20 per square foot ($215 per sq m) per year. In comparison, the owner-occupier’s expense of operating a building in terms of salary costs for all the occupants can total $200 per square foot ($2,150 per sq m) each year. So, while the focus must be on cutting energy use for the sake of the planet, a substantial savings for the building owner-occupier comes from boosting employee productivity as well.
Numerous studies on the effects of indoor air quality and productivity have been performed by the U.S. Environmental Protection Agency, the National Institute for Occupational Safety and Health, Lawrence Berkeley National Laboratory, and universities worldwide.
In fact, if a climate-responsive building designed to enhance indoor environmental quality creates a positive psychological connection to the outdoors and thereby increases employee productivity by up to 10 percent, as suggested following studies by the International Center for Indoor Environment and Energy, it could be argued that the building pays for itself. This kind of design, however, requires a talented and integrated team to take conceptual sketches on a page and make them perform with bricks and mortar.
Although technology itself constantly improves, it is its application that makes the greatest impact. This is where the engineer’s expertise comes into play. When engineers use the latest tools to work closely with architects and analyze the building’s facade and mechanical and electrical systems as an integrated system, they can help influence design and substantially improve performance.
In order to go beyond LEED, architects and engineers need to step up to the plate. Creating integrated designs while specifying green products will result in tomorrow’s improved sustainable solutions.
David Callan is a senior vice president and the director of sustainable design and high-performance building technology for Syska Hennessy Group, a New York City–based consulting, engineering, technology, and construction firm.