Place and Time - Sustainable Design: The Science of Sustainability and Green Engineering - page 183

conditions, values given to parameters, and the propagation of error render our
results even more uncertain.
Thus, professional judgment is crucial to sound design. Such judgment can
only come from learning from the experiences of those who precede us and from
our own experiences. It is a challenge to find the sweet spot between acceptable
and unacceptable risk, but that is the only place where good and green design
can be found.
NOTES AND REFERENCES
1. National Academy of Engineering, The Engineer of 2020: Visions of Engineer-
ing in the New Century , National Academies Press, Washington, DC, 2004,
pp. 50-51.
2. U.S. Environmental Protection Agency, “Green engineering”, http://www.
epa.gov/oppt/greenengineering/, 2006, accessed June 13, 2006.
3. Virginia Polytechnic Institute and State University, http://www.eng.vt.edu/
green/Program.php, 2006, accessed June 13, 2006.
4. This definition comes from the Worcester Polytechnic Institute, http://www
.wpi.edu/Academics/Depts/CHE/About/definition.html.
5. I (Vallero) first heard Vesilind publicly share this profundity during an en-
gineering conference. At first blush, the statement sounds like a truism, or
even silly, unless one thinks about it. There are many, and a growing number
of, enterprises that do not do anything (or at least it is difficult to tell what
they do). They think about things, they come up with policies, they review
and critique the work of others, but their value added is not so “physical.” I
have to say that I envy my family members and friends in construction who
at the end of every working day see a difference because of what they did
that day. This can take many forms, such as a few more meters of roadway,
a new roof, or an open lot where a condemned structure once stood. The
great thing about green engineering is that we can do both. We can plan and
do. I should say we must both plan and do! In the words of the woodworker,
we must “measure twice and cut once.” The good news (and the responsi-
bility) is that the green engineer's job is not finished when the blueprints are
printed. The job is not even over when the project is built. The job continues
for the useful life of the project. And since most environmental projects have
no defined end but are in operation continuously, the engineers get to watch
the outcomes indefinitely. Engineers must get out there and observe (and
oversee) the fulfillment of their ideas and the implementation of their plans.
That is why engineers are called to “do things.”
This reminds me of a conversation I had with a boilermaker who happens
to be my in-law, which points out that engineers need to be aware of the