RCM Analysis - Strategy Decision (Step 3)

This aspect of the RCM analysis relates question six (first part) of the seven RCM questions: What can be done to predict or prevent each failure? Note: This only relates to the maintenance strategy. The other elements of this question, regarding: the maintenance tasks, the economics in terms of MEI and the risk reduction (and residual risk) will be addressed later.

For the Strategy Decision Tree, knowledge is needed regarding the Failure Mode characteristics like: is the Failure Mode Age-Related, or not, and is the failure revealed, or not. This asks for input from a maintenance craft and a reliability engineer. The outcome of this tree is driving the maintenance strategy for this Failure Mode, which can basically be: Condition-Based Maintenance, Time-Based maintenance, or No Scheduled Maintenance.

In the Strategy Decision Tree there are 4 basic questions involved, although at first there are a number of sub questions attached:

1. Is it possible to define a clear, potential failure condition? What is that failure condition? What is the P-F interval and is it reasonably consistent? Can the task be done at intervals less than the P-F interval? Is the residual risk acceptable?
   1. Yes? Determine an on condition task which is technical feasible
   2. Enter the P-F interval value.
2. Is there an age at which the conditional probability of failure increases rapidly? What is that age? Will the restoration or discard task restore the original functionality? Is the residual risk acceptable?
   1. Yes? Determine a scheduled restoration or discard task which is technical feasible
   2. Enter a Save Lifetime value.
3. Is the loss of function caused by this Failure Mode on its own, hidden?
   1. Yes? Is it possible to check whether the item has failed? Is it practical to do the task at the required intervals? Does this task secure the availability needed to reduce the probability of a multiple failure to a tolerable level?
4. Is the risk of the failure acceptable?
   1. Yes? Apply a ‘No Scheduled Maintenance’ strategy (Run to Failure).
   2. No? Redesign may be required.

Together with the information held in the Failure Effects, these answers should drive the maintenance tasks selected next.

When ready click Next.

In case the triggering questions are not needed and the strategy result is known beforehand, you can select that result directly by checking: Overwrite strategy result:

Instruction video

For more information on the execution of RCM analysis in Guides Steps see instruction video: RCM Analysis Guided Steps Episode 7 Video.