Page 101 - Design for Environment A Guide to Sustainable Product Development

80 Chapter Five

FIGURE 5.2 Dual life cycles associated with a product.

• The time scale of the business life cycle is determined by the
rate of technological change and other market conditions that
determine product obsolescence; the time scale of the physical
life cycle is determined by the length of service of a typical
product unit, which may range from days or weeks for con-
sumable products to years or decades for durable goods.
• The responsibility for the business life cycle and the business
impacts (profits or losses incurred) is borne fully by the pro-
ducing company; the responsibility for the physical life cycle
and the associated impacts is distributed among many com-
panies or individuals involved at different stages of trans -
formation; and, in some cases, the responsibility for adverse
impacts may be ambiguous (e.g., liability for waste impacts).
• The sustainability of the business cycle depends upon the abil-
ity of a company to innovate by developing and delivering
product extensions or upgrades that serve the needs of its
markets; the sustainability of the physical cycle depends upon
the ability of various interested parties, including the manu-
facturer, to cost-effectively acquire the necessary energy and
material inputs, and to recover, recycle or refurbish discarded
products.
From a conventional product development perspective, the “busi-
ness life cycle” interpretation is the more meaningful one, since it
provides a framework for making business decisions regarding de -
sirable product features and cost or effort trade-offs. The concurr ent
engineering approach, described above, traditionally has been based
on this model of the business life cycle, with “ilities” associated
with different phases. On the other hand, the notion of the “physical