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Green Building Design
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By Walter Simpson, UB Energy Officer
This guide was published in the March/April 2001 issue of Facilities Manager, the magazine of the Association of Higher Education Facilities Officers (APPA). The article is divided into main text (below), green design case studies, and green building design resources. Additionally, there is a sidebar on cost issues entitled, "Green Backs vs. Green Design -- Green Buildings Cost Less!"
The main text is divided into the following sections:
INTRODUCTION
As campus Energy Officer, I occasionally lecture to architecture students about the University at Buffalo's energy conservation program. I show the students a series of slides depicting the energy design failures of our buildings and how we have tried to correct those failures through literally hundreds of retrofit projects.
The students are shocked when they hear about UB's electrically heated buildings. They are also surprised to hear about new buildings where we have retrofit thousands of lighting fixtures as soon as the buildings were accepted (because the original design called for T-12 lighting a few years after T-8s had proven themselves reliable and more efficient).
At some point near the end of my lecture, I get "the inevitable question," namely, "What is UB doing to improve the design of its new buildings -- so doing all those energy retrofits will not be necessary?!"
I reply by explaining that we stopped building electrically heated buildings a decade ago (though they never should have been built) and we are making progress designing more efficient buildings. But the truth is that we have not come far enough.
GOING BEYOND ENERGY EFFICIENCY
During the 1990's the architectural profession in the United States identified the various principles of "sustainable," "high performance," or "green" building design. This approach goes further than energy efficiency by applying environmental principles to all aspects of building design. "Green buildings" have less impact on the natural environment. They can be healthy, naturally lit, attractive buildings with lower operating and lifecycle costs.
The multiple benefits of green building should speak to college and university facilities managers. There are many reasons why we should be interested in this new architectural movement.
Most campuses have energy conservation, recycling and green campus initiatives. An obvious next step is to include green building design in your palate of green campus programs -- especially considering the substantial, long term operational and environmental impact of new buildings. A campus commitment to green design says something very positive about a school and may provide substantial public relations, recruitment and retention benefits as well.
According to Worldwatch Institute, 40% of the raw materials annually extracted from the earth are transformed into building materials. Buildings are also responsible for an estimated 40% of global energy consumption -- and the associated smog, acid rain and global warming emissions. Climatologists are now telling us that unless we significantly reduce fossil fuel burning and carbon dioxide emissions, average global temperatures could rise by 8 to 10 degrees Fahrenheit by the end of this century. New building design must respond to this challenge by reducing fossil fuel use and carbon dioxide emissions while producing other dividends.
DEFINING GREEN DESIGN
Green building design is a holistic, integrative and collaborative process. It is ecologically, not "ego-logically," driven. It should begin at the first stages of planning and design and consider a variety of design issues. While these elements can be broken down in a variety of ways, here is a representative list:
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"Build/No Build" decision |
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Site decision, planning and design |
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Use of renewable energy |
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Energy efficiency |
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Efficient materials use |
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Ecological building materials |
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Water management |
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Indoor environment |
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Recycling -- during construction and by occupants |
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Building commissioning |
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Green operations and maintenance |
Pop quiz! What is the most conserving, least-polluting building imaginable? Correct answer: the building which is never built!
Green design begins with the decision to build. Our motto should be: build it small if at all. Campus leaders need to ask themselves whether a new building is really needed. Can program needs be met through renovations of existing space? Can space be designed more flexibly and used more efficiently in order to minimize construction?
Given the high cost of new construction, these would seem like obvious questions but they are often given insufficient consideration. New construction is sexy, a way to make a statement and leave a legacy. Moreover, budgetary anomalies may make new construction dollars available while renovation (as well as M&O) budgets are starved. These factors may lead to unnecessary building.
My own school is in a build-out mode, adding new buildings while campus population remains roughly the same. The end result is more "built-space" per student, faculty and staff person than ever before. This structural inefficiency significantly impacts energy and materials consumption.
RESPECT AND RESTORE THE SITE
Site issues become paramount once a decision to build is made. Even if a full-blown Environmental Impact Statement (EIS) is not required by law, this is the time to do an environmental assessment. It is also time to involve the campus community in a public participation process to gain valuable input and build campus consensus.
Urban campuses may have the option of building on a "brownfield," an abandoned commercial or industrial site. While brownfield development typically involves legal and liability issues, remediating and restoring these already used sites is generally environmentally preferable to building on an undisturbed "greenfield."
"Sprawl" describes spread out development which reduces population density, increases travel needs and distances, wastes energy, and destroys open space. Sprawl can apply to campuses as well as communities. Campus siting decisions should promote density, community, and alternatives to gas-guzzling car use.
Of course, sprawl and transportation issues apply to siting new campuses as well as individual buildings. The University at Buffalo newer campus is in the suburbs and is not well served by public transit, bicycling or walking. A faculty colleague once estimated that UB students, faculty, and staff commute by car to and from campus a total of 120 million miles a year! A downtown campus location would have vastly reduced this car travel, annually saving millions of gallons of gasoline and thousands of tons of tailpipe pollution. A downtown UB campus would have also helped revitalize Buffalo, a City which is now a shadow of the thriving commercial and cultural center it was 100 years ago.
Trees and green space beautify campuses. Sacrificing these assets is generally a bad idea. Siting buildings in beautiful natural spots on campus has an appeal but the benefit is lost if building there destroys those spots.
Having selected a site, green design asks planners to respect that site by protecting and restoring its natural systems and by trying to reconnect the site to regional natural systems. Natural assets of a site, such as trees and vegetation, wildlife and habitat, watershed, open space, aesthetics, should be conserved.
By returning rain water to the ground or a wetlands (instead of storm sewers) watershed values of the land can be respected. Paving should be minimized, but, where needed, porous paving materials should be considered. Landscaping should be low maintenance and emphasize native plants. The building should blend in with its natural surroundings, enhancing beauty and enjoyment of the site.
Energy benefits can accrue by adapting to the microclimate of a site. Can the building be shielded from cold winter winds? Can it benefit by cool summer breezes? Trees or berms can deflect or focus winds. Trees and other vegetation can also provide shade and reduce summer ambient temperatures.
Site selection should also be informed by solar access. Can a building be oriented on this site with an unobstructed southern exposure? Are there existing buildings (or other objects) which will cast shadows and block the sun's light and heat?
SUNLIGHT TO THE RESCUE -- USING CLEAN, RENEWABLE ENERGY
Breaking our species' fossil fuel addiction is imperative. Green design helps us do that by promoting the use of clean, free solar energy. Solar homes work even in cold, snowy Buffalo. But what about using solar energy in commercial or institutional buildings? At first blush it might seem difficult but it can be done. There are a number of possibilities:
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Daylighting |
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Passive solar space heating |
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Solar water heating (pools, domestic hot water) |
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Photovoltaic electricity generation |
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Buy "green power" |
The most obvious and proven way to use solar energy in campus buildings is daylighting. Effective daylighting uses sun light to provide superior lighting for occupants while reducing lighting energy costs.
There are lots of ways to do daylighting poorly. For example, direct sunlight may be introduced into buildings, producing uncomfortable glare. Sunlight also may be introduced through skylights or atria which lose too much heat in the winter or gain too much heat in the summer (thus increasing heating or cooling costs). And too often we see daylit spaces where the electric lights are on needlessly during daylight hours.
But daylighting can be done correctly with wonderful results. Good designs avoid direct sun and glare. The light is bounced, diffused and brought into the interior of buildings. Electric lighting is turned off or dimmed with "daylight harvesting" controls. People rave about open floor plans, access to windows, and daylit interior spaces. The best designs allow most occupants to have visual contact with the outdoors. Satisfaction and productivity in these buildings is typically very high.
Daylighting strategies go beyond high tech windows and include horizontal light shelves on windows to reflect sunlight into a space while blocking direct solar gain in summer. Daylighting also makes appropriate use of clerestories, courtyards and atria. A variety of glazing options are available.
Window technology has advanced significantly in the last decade. Different glass coatings and gas fills (between layers of glass) can maximize energy performance. Window selection should be fine-tuned by orientation, location and application. Spectrally selective windows may be specified with high insulating value and different transmissivity characteristics for daylight and solar heat (depending on what is needed for that building type and application).
PASSIVE HEATING AND COOLING
Passive solar heating may be defined as using sunlight for heating without the use of special collectors or mechanical fans or pumps. This is accomplished by south-facing glass which readily admits solar energy (as opposed to rejecting it). The building envelope itself becomes a solar collector. East and especially west-facing glass is minimized to prevent unwanted solar gain in the cooling season.
Clear glass which permits solar heat gain is desirable for passive solar heating. Yet this is a liability in the summer when it will add to the building's cooling load. Some means of sun control or deflection is needed to block sunlight during the warmer months. This can be accomplished with overhangs, shelves, louvers, awnings, trellises, or shades. Computer energy modeling of projected energy use can assist in glass selection, balancing the benefits of daylighting, solar heat gain in winter, and solar rejection in summer.
Since passive solar heating works best with direct sun, it is best accomplished in commercial or institutional buildings in common areas like lobbies (not workspaces). Sufficient thermal mass (or a means of removing heat) is required to avoid overheating a sun-heated space. Thermal mass may be provided by normal construction materials such as a thick masonry floor (with dark colored tiles) or a mass wall. Special features such as water drums or columns can also be used.
GREEN POWER -- SOLAR ELECTRICITY
A green building should run on green power! That power can be generated on site or purchased.
One option is photovoltaic (PV) electrical generation. Green designers may incorporate PV into their designs despite its relatively high cost per KW of generating capacity.
As a rule of thumb, one square foot of photovoltaic solar-electric panel will produce about 10 watts of peak electric power if the panel is facing the sun and in full direct sunlight. This is not a lot of power. Real life energy production from PV is a function of location, time of year, time of day, weather conditions, and panel tilt angle. To power an entire building with on-site PV means a lot of PV surface area or a very efficient building (or both).
We tend to think of PV as panels set up on racks or in sun tracking arrays. But PV need not be an add-on. PV can now be incorporated into the building envelope itself. Building Integrated PV (BIPV), as it is called, incorporates PV in curtain wall and roofing materials. PV (electricity-generating) windows are being developed. Needless to say, BIPV promises aesthetic and cost-saving benefits. In any event, greater use of PV will bring costs down.
What about fuel cells? Fuel cells are not a renewable energy source as long as they are running on natural gas (as most fuel cells do today). Nonetheless, some green buildings utilize fuel cells because they produce cleaner, more efficient electricity than the grid. Fuel cell prices will also come down with greater use. Fuel cells will eventually become renewable technologies once they are powered by solar-wind-biomass-generated hydrogen.
That leaves the option of buying green power in the deregulated electric marketplace.
In early 2001, electric deregulation looks like a colossal failure. Californians are paying much more for electricity than they did before deregulation. And they have experienced rolling blackouts as demand threatens supply. In my own state, New York, deregulation undercut much of the conservation and efficiency regime which existed in the early 1990's. Not surprisingly, electricity consumption is now climbing and there is increasing concern about generating capacity.
Nonetheless, electric industry deregulation may eventually make it possible for college and university campuses to buy environmentally friendly clean electricity. This power would come from newly developed windpower, biomass, PV, or landfill gas generating capacity. A green facility should be willing to pay a price premium to purchase green power.
NEGAWATTS, NOT MEGAWATTS -- MAXIMIZE ENERGY EFFICIENCY
It goes without saying that green buildings must be energy efficient. By focusing on energy efficiency, the percentage of building energy needs provided by the sun can be maximized and fossil fuel reliance minimized. It is not enough to meet energy codes and standards such as ASHRAE 90.1. Green designers have pointed out that meeting the energy code should be no source of pride because if your building was any worse it would be illegal!
There are literally hundreds of strategies for designing energy efficient buildings. Here are some of the basic issues and opportunities:
Building Envelope
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Surface area to volume ratio (building shape, attached vs. stand alone, below ground vs. above) |
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High level of insulation and tight construction for colder climates |
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Location of entrances |
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Super-windows (optimized for application) |
HVAC -- General Considerations
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First reduce all heating and cooling loads |
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Size equipment smaller (for reduced loads) |
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High efficiency equipment (including at part load) |
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VAV vs. constant volume distribution systems |
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Setback thermostats |
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Proper zoning |
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Heat recovery |
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CO2 sensors and "demand control ventilation" |
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Fuel choice (natural gas is cleanest fossil fuel; solar is much cleaner) |
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High efficiency fans, pumps and motors |
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EMS (to be used as more than sophisticated time clock) |
HEATING
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Boilers -- modular, condensing; low NOX |
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Cogeneration -- natural gas-fired combined cycle; low NOX |
COOLING
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Gas-fired chillers |
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Dehumidify only when necessary |
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Minimize summer reheat |
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Avoid CFC and HCFC refrigerants |
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Use economizer/free cooling cycles |
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Operable windows (instead of mechanical AC) |
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Natural ventilation including solar thermal chimneys, wind scoops, etc. |
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Evaporative cooling (arid climates) |
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Desiccant dehumidification (humid climates) |
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Ground source heat pumps |
LIGHTING
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Maximize daylighting |
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Energy efficient T-8 lighting with electronic ballasts and reflectorized fixtures |
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Lighting controls (motion detectors, photocells, daylight harvesting dimmers) |
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Lower light levels (more appropriate to computer use) |
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LED exit and traffic lights |
APPLIANCES AND OFFICE EQUIPMENT
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Buy maximum efficiency (Energy Star-compliant) |
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Enable power management features |
How energy efficient can your new building be? Efficient green commercial or institutional buildings can save 25 - 50% or more of the energy which would be required by conventional code-compliant building design.
ENVIRONMENTALLY FRIENDLY BUILDING MATERIALS
Green design uses resources efficiently and selects environmentally friendly building materials and products. Obviously, smaller buildings use less material. Flexible, adaptive designs allow smaller structures to meet more needs -- thus conserving materials. Designing interior spaces attractively with exposed structural members and less decorative surfaces, coverings, and finishes can also reduce the amount of materials required.
Ecological materials selection is a specialty unto itself. The designer must know how to identify and specify materials and products which perform well and have the least impact on the environment over their lifecycles. In reality, a balancing act is required but the goal is to pick materials/products which are:
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Local |
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Indigenous |
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Low embodied energy |
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Reused, recycled and/or recyclable |
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Renewable and sustainably harvested (no old growth timber) |
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Non-toxic/non-polluting in manufacture, use and disposal |
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Contain no ozone-depleting CFCs and HCFCs |
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Durable |
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Low-maintenance |
The embodied energy of a product refers to the amount of energy it takes to extract raw materials and make the product. In effect, the product "contains" this energy and its energy-related pollution (as well as any other pollution created by the extraction and manufacturing process). For instance, ten simple clay fired bricks "contain" the energy equivalent of one gallon of oil (say 140,000 BTUs).
The embodied energy of a product is generally less if it is made from recycled waste material, e.g. approximately 10-20% less for recycled glass and plastic, 50-60% less for recycled steel, and 95% less for recycled aluminum.
GOING EASY ON WATER
Green buildings are frugal on water. This makes sense because in many areas water is in short supply. Also, domestic tap water contains embodied energy (the energy required to purify it before use, pump it, and treat it after use) and this can be saved through water conservation.
In addition to using low-flow plumbing fixtures, green designers may specify waterless urinals and composting toilets. Gray water from sinks, showers and laundries may be reused for purposes not requiring potable water (e.g. toilets, irrigation, vehicle washing). Rainwater may be collected from roofs and used similarly. Rainwater may also be used to grow planted "green roofs" which have recreational, wildlife habitat, educational, and roof shading benefits.
Alternative water treatment strategies may be employed including the use of on-site biological waste treatment, using microbes and plants to break down waste. This can be accomplished with constructed wetlands or "living machines" which mimic the biological processes of wetlands.
A HEALTHY INDOOR ENVIRONMENT
Green building design seeks to provide the healthiest of indoor environments. This enhances occupant satisfaction and productivity as well as reduces the risk of ending up with a "sick building" (and all the liabilities associated with that term). Thus, green designers address:
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Indoor air quality (IAQ) |
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Light quality and light levels |
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Acoustic issues and noise control |
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Comfort and controllability of systems |
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Contact with nature and outside |
Source control is the primary IAQ strategy. Potential pollutants are identified and minimized at the source. The design seeks to exclude emissions from neighboring buildings, vehicles, and soil contamination (including radon). Air intakes must be located away from sources of pollution. Effective moisture control is used to curb humidity and prevent mold problems. Green designers specify low or zero VOC- (volatile organic compounds) and odor-emitting building materials and equipment.
Ventilation is regarded as the secondary strategy for IAQ. This involves more than simply meeting ASHRAE ventilation codes and providing sufficient outside air to dilute and remove pollutants. Effective diffusers and proper zoning are essential to mix air or segregate it as appropriate.
"Economizer" cycles (which use 100% outside air when the "enthalpy" or "heat content" of outside air is less than that of indoor air) can be used during the swing seasons and summer to cool and flush a building. Use of heat recovery systems minimizes winter and summer energy penalties associated with mechanical ventilation of buildings. "Demand Control Ventilation" (DCV) is another energy efficient ventilation strategy. DCV uses carbon dioxide sensors to gauge building fan zone occupancy, controlling outside air dampers and air volumes accordingly.
What about operable windows? Surely, they go against the grain of commercial and institutional building design of the last few decades. We think of these buildings as being sealed boxes. Heating and cooling costs can increase if windows are open, depressurizing spaces and allowing additional volumes of unconditioned outside air to enter.
But operable windows provide ventilation, a sense of control for occupants, and a way of getting in contact with outside -- all qualities of a healthy building. Green design asks designers to reconsider operable windows and mechanical air conditioning for commercial and institutional buildings. In some regions, operable windows and passive cooling strategies may be able to replace mechanical air conditioning entirely --especially if building cooling loads are minimized. In other regions, operable windows may be part of an efficient building cooling strategy which relies on windows (and other passive ventilation) for cooling during mild parts of the cooling season and mechanical air conditioning when it gets really hot and humid.
Operable windows and energy efficiency need not be incompatible. Window frame switches can be used to shut off mechanical air conditioning to rooms with open windows. The challenge is to design a system which keeps windows closed during cold weather and permits them to be open when the enthalpy of outside air is acceptable for indoor conditioning.
RECYCLING, CONSTRUCTION, AND BUILDING COMMISSIONING
Recycling is addressed in two ways by green building designers. First, it is part of the architectural program in order to insure that adequate systems and space are incorporated into the building design to facilitate maximum recycling by occupants. Secondly, construction and demolition (C&D) debris must be recycled during the construction process. A full waste management strategy should be developed to address construction waste, material salvage, packaging reuse, and hazardous substances.
Construction issues also include stringent environmental health and safety measures on the job site as well as measures to protect the natural features of the site, rescue trees, salvage top soil, minimize run off and pollution, control noise and dust, and address community concerns.
Green design recommends a commissioning process to maximize building performance. The process generally involves the following:
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Testing and performance protocols |
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Dedicated commissioning agent |
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Confirmation of system designs, specifications and installation |
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Confirmation that equipment and systems operate as designed |
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Performance optimization |
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Training of M&O facilities staff |
Ideally, the commissioning process begins during the design phase of a project and concludes after the building is accepted by the owner. Commissioning adds to the first cost of a building but it produces a healthier, better performing building with operating and lifecycle savings which can exceed the costs of commissioning many times over.
GREEN BUILDINGS ARE PART OF THE CURRICULUM
Facilities managers at educational institutions should be particularly interested in the pedagogy of green buildings. An ecological building should teach students, faculty and staff. It should inspire everyone to decrease his or her "environmental footprint" and live lightly on the Earth. To accomplish this, green design features and systems should be visible. Displays or other illustrative and written materials should be available to tell the "green story" of the building. Moreover, a green building should be loudly proclaimed to the wider community. It deserves press events, newspaper articles, tours, and TV coverage to convey its message to a larger audience.
Of course, the educational value of the building can be enhanced if students, faculty and staff (and members of the wider community) are involved in the design process. Also, the learning process can continue after the building is occupied by asking how the building can now be optimized. The designer can be challenged to produce a structure capable of evolving and improving itself.
GREEN DESIGN -- SOME TIPS ON GETTING STARTED
Green design begins early enough to affect the decision to build and (if yes) the decision to locate a building in a particular site. The architect or design consultant should be selected on the basis of a RFP and selection process which explicitly calls for green design credentials and capabilities.
Your green architect should be asked to meet specific performance goals, such as (percentages provided for example only):
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Exceed energy code of ASHRAE/IES 90.1 by 50% |
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Meet 20% of building heating load with passive solar |
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Generate 15% of building electricity requirements by PV |
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Achieve a daylight factor (DF) of 2% on a work plane 15 feet from the building perimeter (DF is % of light available indoors vs. outdoors under an overcast sky) |
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Specify that 30% of materials will be minimally 20% post-consumer recycled-content or salvaged, based on total materials cost |
Over-building and over-sizing equipment should be discouraged. Compensation for the architect and design team should be tied to achieved building performance.
Your architect may wish to strengthen his or her green design capabilities by hiring a sub-consultant with specific expertise in daylighting, energy modeling, green materials selection, etc. The green design process can be enhanced in other ways as well. For example, design charettes can be arranged to permit other architects and engineers (along with students and faculty) to review and critique building design as it evolves. Green design can also be facilitated by using the LEED Green Building Rating System to guide and evaluate your design. LEED (Leadership in Energy and Environmental Design) is a voluntary, consensus-based, market-driven rating system developed by the U.S. Green Building Council. (See Resources for more information about LEED.)
OVERCOMING BARRIERS, JUMPING HURDLES
Of course, all of this supposes facilities managers can overcome very real barriers to green design including:
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Concerns about higher first costs ("We don't have the money.") |
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Concerns about delaying project schedules ("We don't have time.") |
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Lack of in-house green design expertise ("We don't know how to do it.") |
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Heavy workload by in-house staff ("We can't do anything more.") |
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Organizational culture ("We've never done it that way before.") |
The costs issue can be addressed in a variety of ways (see sidebar). Time concerns may be harder to address if projects are fast-tracked. Can schedules be reconsidered so that projects are done right, producing minimum long-term costs and maximum long-term benefits?
When workload is a barrier, it may be time to re-evaluate priorities and/or call for "reinforcements" in the form of outside contractors or consultants. Both approaches involve costs but green design is worth it. Consultants can provide staff training and strengthen in-house expertise. In-house resources and expertise can also be enhanced by selecting a green architect as the next architect you hire for your facilities team. And organizational culture can change if facilities leaders commit to green design by encouraging and rewarding managers and staff who rise to the challenge.
IT'S TIME TO GO GREEN -- CONCLUDING ON A PERSONAL NOTE
I am the happy father of a ten year old girl (Skye) and a twelve year old boy (Jay). I love my children with all my heart. Sometimes I wonder what the world will be like when they are my age. What kind of world are we leaving the next generations?
We've all heard the admonition, "think globally, act locally." I try to do both. But sometimes when I reflect on the state of our world, I am overwhelmed with future fear. What will happen if human population doubles? What will happen if we do nothing about clear-cutting forests or global warming?
I must confess that for me one of the attractions of green building design is that it is not "doom and gloom." Instead it is positive, hopeful and even inspiring. How environmentally benign and sustainable can we make our buildings? It's time we found out!
Acknowledgements
While the author takes full responsibility for the text, he wishes to thank the following readers for their comments and suggestions:
William Bobenhausen, AIA, Director of Sustainable Design, Steven Winter Associates, Norwalk, CT.
Hillary Brown, AIA, Assistant Commissioner, Sustainable Design and Construction Program, New York City Department of Design and Construction.
William G. Reed, AIA, Natural Logic, Inc., Chevy Chase, MD.
Downloadable version: [ms-word.doc]
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