Page 188 - Design for Environment A Guide to Sustainable Product Development

Analysis Methods for Design Decisions 167

can be used to show the relationships between en vironmental
metrics and other cost or performance metrics, such as reli-
ability and durability.
A full treatment of these many approaches is beyond the scope
of this book. However, the following sections describe selected envi-
ronmental performance assessment methods, along with examples
of their application. The five categories of methods discussed below
correspond to the rows of Table 9.1. Chapter 10 discusses the integra-
tion of these methods into a product life-cycle management process.

Tangible Evaluation

Tangible evaluation methods involve real-world physical or chemical
procedures for assessing the characteristics of a product or compo-
nent. Unlike the rest of the analysis methods discussed below, tan-
gible evaluation provides observable results rather than theoretical
predictions based on models and assumptions. Applications of these
methods include:
• Acceptance requirements for design choices; for example,
the criteria for material selection may specify physical prop-
erties, such as moisture resistance, strength, color, or other
characteristics that can be evaluated directly. Relevant to DFE,
the USDA has introduced a bio-based material standard that
relies on carbon dating to identify the nonfossil fraction of
carbon atoms in a given material.
• Functional testing of design performance; for example, elec-
tronic products are frequently subjected to actual use tests
that simulate the wear and tear associated with repeated use
or abuse, such as being dropped onto a hard surface.

Qualitative Assessment
Qualitative assessment methods have a number of obvious advan-
tages over quantitative methods—they are easier to apply, require
minimal data, and can be useful in spite of large uncertainties. For
many companies, such methods are the logical first step in imple-
menting DFE because they can provide value without requiring
large resource expenditures. Qualitative methods are generally used
to test whether product design choices satisfy certain environmental
criteria, such as recyclability, energy efficiency, and absence of toxic
constituents.
In practice, qualitative assessment methods have countless varia-
tions; the following illustrates two common types of methods: check-
lists and matrices.