ABSTRACT
When considering the life of built infrastructure, the terms Design Life and Service Life are commonly used and incorrectly exchanged for the same meaning. Both terms refer to the length of time that the built item will perform for its intended purpose; the key difference between the terms is intended versus actual performance. This chapter discusses these terms within the context of ageing and considers life cycle implications. Service Life begins at the completion of construction and ceases at the time of decommissioning/demolition or failure of the infrastructure. The problem of ageing leading to premature replacement of built infrastructure before expiry of Design Life has a legacy of economic, environmental and social impacts. Design Life and the consideration of ageing during the design and construction stages are critical for construction of durable infrastructure. Ageing of infrastructure has drawn attention to how Design Life is considered by designers, builders and asset owners/managers prior to construction.
