Condition assessment (CA) of systems addresses the system perspective as it applies to understanding the current condition and provides indications about future behaviour. A standard has not been identified for system CA, but the process follows logic similar in many ways to that for SMP assessment. The assessment includes screening of components captured within the boundary, and can address all components types. The screening provides a means of identifying those components requiring a greater focus for the balance of the assessment. The specific ageing assessment sections of the process consider components or groups of components, following the processes identified in the component CA discussed further below. In many cases, SCCs will be assessed under individual component CAs or LAs depending upon their criticality. The system CA brings the overall results together from a system perspective.

The system CA focus impacts on the level of effort and the content. For PLiM programme CAs, there is interest in reviewing the ongoing programme to address ageing elements, together with understanding the current condition of the components. The screening typically performed reflects the impact of component failure on safety and production. The report provides a technical basis for improvements to the maintenance strategy, identifies short term requirements to confirm the prognosis, reviews potential obsolescence issues, and provides a prognosis for the service life period under consideration. The technical basis is developed through consideration of susceptibility to ageing related degradation mechanisms (ARDMs), review of the current status with regard to the ARDMs of interest, and a review of existing programmes to identify and mitigate these ARDMs.

For CAs focused on a specific need, such as defining elements of refurbishment, those items handled by normal maintenance would require less scrutiny. Typically the overall assessment ensures there are no issues associated with the maintenance trends and obsolescence, and gives a prognosis whether the component should be replaced during the refurbishment outage. The assessment relies on the review of ARDMs as discussed above.