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Obsolescence & Service Life

Obsolescence & Service Life. H. Scott Matthews January 27, 2003. Recap of Last Lecture. Built infrastructure deficiencies lead to ‘needs’ Needs studies should estimate NEEDS not WANTS Costs of infrastructure need to be managed and planned over life cycle

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Obsolescence & Service Life

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  1. Obsolescence & Service Life H. Scott Matthews January 27, 2003

  2. Recap of Last Lecture • Built infrastructure deficiencies lead to ‘needs’ • Needs studies should estimate NEEDS not WANTS • Costs of infrastructure need to be managed and planned over life cycle • Infrastructure generally built to last longer than it would actually be useful

  3. Obsolescence • Condition of being antiquated, old-fashioned, or out-of-date • No longer meets current needs or expectation levels • Aging, technology, standard change • 2-yr old computers good example • Inability to meet changing performance requirements

  4. Obsolescence & Service Life • “Always remember that someone, somewhere is making a product that will make your product obsolete” • -Georges Doriot • “Planned obsolescence” by Vince Packard’s The Waste Makers • Practice of deliberately designing products to last for a shorter period of time • Systemically doing this leads to inferior products

  5. What Causes It? • Technological change • Regulatory change • SDWA forced upgrades • Economic / social changes • Value / behavior changes

  6. Economics • Performance = P(S,D,t) • S = Supply of infras. Services = S(X) • X = set of functional characteristics • Planners want adequate X, S over time • ‘Satisficing’ (Simon 57) • D = demand for these services

  7. “Failure” • Failure as not meeting expectations • Happens when P(t) < PF • Need to maintain performance level • Expectations increase over time P PF TD

  8. Service vs. Physical Lives • Physical Lives: time it takes for infrastructure to wear out/fail • Predicting this may be irrelevant • Service life: time actually used • In general these 2 are different • Power plants become obsolete because of technology/policy changes • In some cases, tax code drives expectations

  9. Connections • “Design service life” only meaningful if defined in terms of obsolescence • Assumptions about lifetime will likely change over time • Infrastructure seldom abandoned before replacement in place • Expectations will increase • Need to consider expectations and deterioration functions

  10. Rates of Change • Information economy is making older transport modes obsolete • E.g., ground -> air shipping • How long should infrastructure last? • Physical or service? • “How long do you want to use it?” • Where will it go when we’re done? • What could we do with Roman roads now?

  11. Strategies to Mitigate • Plan and design for flexibility • Build to assure optimum performance level is achieved • Monitor change to defer obsolescence • Refurbish and retrofit early

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