Managing Asset Life Cycle Decisions and Activities

What this module covers

Module 3 carries 10 questions. It covers what actually happens to assets across their lives, and why decisions at one stage fix the cost of the stages that follow.

Why acquisition matters most

Design and acquisition decisions commit most of the cost an asset will ever incur. They set how much it costs to run, how maintainable it is, how long it lasts and how easily it can be disposed of. They are also made when least is known. That combination is why whole-life thinking has to start at the drawing board, not at handover. A pump that is cheaper to buy but can only be removed with a crane, in a plant room with no crane access, is a saving that costs money at every overhaul.

Systems engineering is the discipline that carries business requirements through into technical requirements and the system specification. It decomposes and defines on the way down, then integrates and validates on the way up. Its purpose is to avoid building something that works but doesn't deliver what the organisation needed.

Maintenance strategies

Know the approaches and what triggers each one:

• Reactive, or run to failure: acting after failure. A legitimate choice when consequences are low and prevention would cost more. A failure of management when it is the result of neglect.
• Time-based preventive: triggered by elapsed time or usage, whatever the condition.
• Condition-based and predictive: triggered by measured evidence of deterioration, such as vibration, oil analysis or thermography.
• Design-out: removing the failure mode by modifying the asset.

A reliability-centred approach chooses between these by starting from function and failure mode. What must the asset do, how can it fail to do it, and what does that failure cost?

Whole-life cost and optimum life

Whole-life cost covers acquisition, operation, maintenance and disposal together, and it is the basis on which options should be compared. It includes costs such as training, energy and mid-life overhaul. It excludes general overheads like sales and marketing. Optimum life is an economic idea: the life that gives the lowest equivalent annual cost. It is not the manufacturer's design life, and not the longest the asset could safely be kept running.

End of life, obsolescence and information

End of life is a set of options, not a yes-or-no. You can continue under a revised regime, refurbish, replace, repurpose, or dispose without replacing. Current condition, forecast demand, whole-life cost and legislation all matter more than the design life assumed before the asset entered service. Obsolescence threatens assets that still work perfectly well. The danger is not that they break, but that they can't be put back into service once they do. Keep asset information current: a record that no longer matches what is installed quietly corrupts every decision made from it.

Where marks are lost

• Comparing options on purchase price rather than whole-life cost
• Confusing preventive, predictive and reactive maintenance
• Treating design life or full depreciation as the trigger for replacement
• Forgetting disposal obligations, which should be anticipated at acquisition
• Assuming run to failure is always poor practice