Life Cycle Management of Critical Assets

Critical assets are managed proactively. In terms of renewal planning, that involves assessing remaining economic life using data from condition assessment and other survey work.

Some assets are individually more critical than others. In particular, as asset-value and/or the potential consequences of failure increase, there is an increasing driver to take proactive measures to reduce risk, control deterioration and thereby extend asset life.

Measures of asset criticality can be used to define a prudent life cycle management strategy, which can encompass:

  • Different degrees of proactive management
    • Prevent failure... usually more applicable to large complex assets like dams and treatment works; when applicable to pipelines, designing out risk (e.g., via changing the line) might be a better option than managing risk
    • Avoid failure... applicable to high value/high consequence pressure pipes, requires proactive condition assessment and estimation of remaining economic life
    • Prefer not to fail... applicable to medium consequence pressure pipes; as per avoid failure, but with more risk tolerance applied
  • Reactive management...

Maintenance effort and focus will vary across an asset’s life, but the overarching strategy will remain the same unless an asset’s criticality changes.

Proactively managed assets are termed ‘critical’ and generally represent the minority of a utility’s asset stock. For highly critical (prevent fail) assets, economic considerations can warrant renewal before failure occurs. More usually, a proactive approach is taken to assess end of life and thereby manage risk.

When considering proactive intervention options, a prudent approach is to prioritise assets using risk-based analysis.

Generally, the consequence of failure can be represented by a specified scenario (e.g., worse but still realistic case), so effort then reduces to understanding the likelihood of failure when assessed in light of corporate risk appetite.

In many cases, there will only be very limited failure data available, so condition assessment techniques must be used to determine the level of asset deterioration, with analysis then undertaken to assess risk via the modelling of load-capacity relationships. This is a costly activity and the application of different techniques has to be carefully planned to allow valid conclusions to be drawn.

PARMS T&D is designed to help leverage best available data and thus target further data collection in a cost-effective manner.

The STAR Framing

To aid thinking around critical assets, we use the acronym STAR:

  • Screen: use available data to develop understanding of risk, based on a ‘lines of evidence’ approach
  • Target: use outputs from the screening to prioritise assets for further risk assessment.
  • Assess: use a range of inspection, condition assessment and survey techniques, or analytics to evaluate the risk of target assets further
  • Respond: use the evidence generated to make efficient management decision, including specifying further assessment if necessary or undertaking risk mitigation activities, including capital and non-capital solutions as deemed prudent

PARMS Critical

PARMS Critical is a decision support framework for critical assets that embeds the STAR approach within an iterative evidence-building process that ensures both cost effective prioritisation and subsequent development of prudent business cases.

The PARMS Critical philosophy is the foundation of the PARMS T&D decision support suit.

PARMS T&D