It is rarely possible to do everything we would like to reduce the environmental impact of building projects. It takes time to research alternative design and construction systems; new materials may not have proven track records; higher costs may be an impediment; or clients simply might not be interested. Therefore, it makes sense to figure out where our efforts will do the most good. Where should we focus most of our attention in designing and building structures that will have minimum impact on the environment? Some designers and builders who emphasize sustainability have picked out just one aspect of green design, often recycled-content building materials, and hold that up as their flag. Material selection is one of the most visible green building strategies and often the easiest to point to but usually not the most important. Deciding which measures are most important is no simple task. Here we take a look at some of the factors to consider and suggest a listing of priorities in green design. This sort of list can never be considered final: we look forward to an ongoing discussion of priorities from which we might all learn.
Several related factors should be considered in making objective decisions about where our investments of time and money will do the most good in reducing environmental impact. First, we need to understand the most significant environmental risks. These may be global in nature, or more specific to your particular region or site. Prioritizing these risks is difficult because often they occur in unrelated fields, with no way to make direct comparisons. Which is worse, the release of toxic waste, destruction of an endangered species' habitat, or stratospheric ozone depletion? Interestingly, scientists often come up with very different priority rankings than the general public on these issues (see sidebox). The second critical factor is an understanding of how our buildings contribute to these risks and how significantly the measures we adopt can help the situation. We may decide, for example, that ozone depletion, a global problem, is more important than the survival of a particular bird species. But, if a building project we are working on could eliminate the last remaining habitat of that species - a major contribution to its demise - that is probably a higher priority than reducing our use of HCFCs, which are contributing incrementally to ozone layer damage. The third factor has to do with the specific opportunities presented by each individual project. On some projects one can dramatically affect a building's performance in one particular area with very little investment, while addressing other impacts might prove very expensive and only minimally effective. Energy performance, for example, can sometimes be improved by simply adjusting a building's orientation, while using a recycled content floor tile might increase cost significantly for relatively little gain. Finally, we have to consider the available resources and agenda of the client. There are often measures that can be taken at no additional cost, some may even save money, to reduce environmental impacts. Implementing such measures should be a "no-brainer". Other measures might increase the first cost of a building but save money over time. How far we can go with such measures, in length of payback and size of initial investment, depends a great deal on the resources and willingness of the client. In some cases a third party can be found to finance such measures and share in the savings. There are also measures that are important environmentally but do not offer the building owner any direct financial reward. Pursuing these strategies depends on the client's good will, environmental commitment, and interest in some of the less tangible benefits that may result, such as good public relations. Given all these factors to consider, deciding which environmental goals to pursue on a given project might seem overwhelming. To provide a more concrete starting point, we have come up with a list - our priority ranking of measures to reduce the environmental impact of buildings. Clearly the order is arguable, and for specific projects and climatic regions a different order will apply. All the measures listed below are important, and one should definitely implement any that are feasible within the constraints of a particular project.
This list - a builder's dozen - reflects our sense of where you might look to get the most bang for your buck. Each item is followed by a few sample strategies for implementation, and a discussion of the likely cost implications.
Ongoing energy use is probably the single greatest environmental impact of
a building, so designing buildings for low energy use should be our number
one priority. Decisions made during the design and construction of a
building will go on affecting the environmental performance of that
building for decades to come - perhaps even centuries - through energy
consumption. An integrated design approach can often take advantage of
energy savings that become feasible when the interaction between separate
building elements, such as windows, lighting and mechanical systems, are
considered.
Existing buildings often contain a wealth of material and cultural
resources and contribute to a sense of place. In some cases the workmanship
and quality of materials that has gone into them is almost impossible to
replicate today, making restoration all the more valuable.
To reduce environmental impacts, we must address transportation. Even the
most energy efficient, state-of-the-art passive solar house will carry a
big environmental burden if its occupants have to get into a car each
morning and commute 20 miles to work. Since the 1940s, zoning and land-use
planning have, in general, been impediments to, rather than supporters of,
responsible transportation patterns. Effective land-use planning can also
help to foster strong communities.
Smaller is better relative to the environment, and no matter what the
materials, using less is almost always preferable, as long as the
durability or structural integrity of a building is not compromised.
Reducing the surface area of a building will reduce energy consumption.
Reducing waste both helps the environment and reduces cost.
In fragile ecosystems or ecologically significant environments, such as old
growth forests or remnant stands of native prairie, this might be the
highest priority.
Most, but not all, environmental impacts associated with building materials
have already occurred by the time the materials are installed. Raw
materials have been extracted from the ground or harvested from forests;
pollutants have been emitted during manufacture; energy has been invested
throughout production. Some materials, such as those containing ozone
depleting HCFCs and VOCs, continue emitting pollutants during use. And some
materials have significant environmental impacts associated with
disposal.
The longer a building lasts, the longer the period of time over which the
environmental impacts from building it can be amortized. Designing and
building a structure that will last a long time necessitates addressing how
that building can be modified to satisfy changing needs.
This is largely a regional issue. In some parts of the country, reducing
water use is much higher on the priority list.
Though some people separate the indoor environment from the outdoor
environment, the two are integrally related, and the health of the building
occupants should be ensured in any "sustainable" building. With many
clients, this is the issue that first generates interest in broader
concerns of environmentally sustainable building.
For more and more materials, sorting and recycling job site waste is paying
off economically, and it can certainly generate a good public image.
In addition to creating buildings with low environmental impact, you should
practice environmentalism in your own business, thus serving as a model for
other design or construction firms.
In deciding which measures to pursue on specific projects, consider the relative benefits of the different measures. You might begin by customizing the list of priorities for your own region. In an arid climate, for example, water conservation would go near the top, while in a city prone to smog inversions, transportation alternatives might be the most important. Refer to your list as you consider each project and identify the areas where you can do the most for the environment. Pick the low hanging fruit first, and go after the tougher issues as time and resources allow. Return to buildings you have completed to see which systems are working and which are not, and how occupants have modified your work to fit their needs. When possible, use your buildings to strengthen the link between occupants and the global environment through education and direct interaction. Finally, if you are incorporating environmental features into your work, take advantage of that fact in your marketing efforts. We hope that this ranking will inspire others who regularly think about environmental impacts of building to offer their opinions. Like most lists and categories, our list serves a purpose but also risks compartmentalizing the design and construction process. Often the most significant opportunities for benefitting the environment come from a careful integration of the design to take advantage of synergies between building elements. The most elegant design solutions - those that reduce complexity while solving multiple problems - will not be found by considering each item on this list in isolation.
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editor Nils Larsson larsson@greenbuilding.ca
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