Sustainable Design and Social Responsibility - Sustainable Design: The Science of Sustainability and Green Engineering - page 188

Engineering and architecture have always been concerned with space. Archi-
tects consider the sense of place. Engineers view the site map as a set of fluxes
across the boundary. Time is a bit more difficult. The design must consider short-
and long-term impacts. Sometimes these impacts will be on futures beyond ours.
The effects may not manifest themselves for decades. In the mid-twentieth
century, designers specified the use of what are now known to be hazardous
building materials, such as asbestos flooring, pipe wrap, and shingles, lead paint
and pipes, and structural and mechanical systems that may have increased exposure
to molds and radon. Those decisions have led to risks to people inhabiting these
buildings. It is easy in retrospect to criticize these decisions, but many were made
for noble reasons, such as fire prevention and durability of materials. However,
it does illustrate that when viewed through the prism of time, seemingly small
impacts can be amplified exponentially in their effects.
Sustainable design requires a complete assessment of a design in place and time.
We mentioned that the effects can be decades away. In fact, they may be centuries
or even millennia in the future. For example, the extent to which we decide to
use nuclear power to generate electricity is a sustainable design decision. The
radioactive wastes may have half-lives of hundreds of thousands of years. That is,
it will take all these years for half of the radioactive isotopes to decay. Radioactive
decay is the spontaneous transformation of one element into another. This occurs
by irreversibly changing the number of protons in the nucleus. Thus, sustainable
designs of such enterprises must consider highly uncertain futures. For example,
even if we place warning signs about these hazardous wastes properly, we do not
know if the English language will be understood.
All four goals of green engineering mentioned above are supported by a
long-term life-cycle point of view. A life-cycle analysis is a holistic approach to
considering the entirety of a product, process, or activity, encompassing raw ma-
terials, manufacturing, transportation, distribution, use, maintenance, recycling,
and final disposal. In other words, assessing its life cycle should yield a complete
picture of the product.
The first step in a life-cycle assessment is to gather data on the flow of a material
through an identifiable society. Once the quantities of various components of
such a flow are known, the important functions and impacts of each step in
the production, manufacture, use, and recovery/disposal are estimated. Thus, in
sustainable design, we must optimize for variables that give us the best performance
in a temporal sense.
REVISITING THE HARM PRINCIPLE: MANAGING RISKS
The harm principle espoused by John Stuart Mill basically, tells us that even when
benefits clearly outweigh costs, we are still morally obliged not to take such action
if it causes undo harm to even a few people. This is a difficult concept for those