Design for system retirement

Abstract

Abstract While almost all system design texts identify that designing for life cycle is an essential aspect of system design, only a few make mention of designing for disposal at the end of life, and fewer still provide any guidance how to design to address this important issue. Further, disposal at the end of life is just one of the options in the Retirement Stage of the system life cycle—ideally, the system will be transitioned into another life cycle, on the basis that the longer a system exists in some form, there is lower cost and lower environmental impact resulting from the need to develop replacement systems. A good system design, therefore, should not only achieve longevity of use in the first life cycle of the system but should aim for longevity of use in all subsequent life cycles, until disposal is the only viable option that remains for the system elements. This paper begins by addressing the potential for multiple life cycles of a system, making a distinction between end of life and end of life cycle, and suggesting a useful taxonomy for the terms associated with system retirement. A simple three-step methodology is then presented for the consideration of the issues relevant to design for all aspects of retirement of a system: identify the reasons for retirement, identify the potential retirement methods (making use of the presented taxonomy), and identify the design issues that arise from the consideration of each retirement method. A simple example of the use of the methodology is presented to provide the basis for some discussion and conclusions.