Page 35 - RCM - A practical Guide_V1

RCM - A Practical Guide

Figure 6 - Tailored decision diagram

6 - What, if anything, should be done to predict or prevent each failure?

Using the failure mode
Irrespective of whether a functional failure is hidden or evident, the criteria for question 6 is the same.
In the failure effect section of this handbook, it was mentioned that the effects should detail (or at
least consider) recording the physical effect of the failure mode on the asset. This is where that detail
pays dividends.
The applicability of mitigation strategies, for a given failure mode, will based largely on the
characteristics of that failure mode. Under the guise of question 6 of the 7 questions of RCM we are
given two options:
Predict the failure - In RCM terms, On-condition maintenance
Prevent the failure - In RCM terms, Hard-time maintenance
Is an on-condition (OC) task applicable and effective?
Thinking back to the six patterns of failure, OC maintenance is not dependent on the conditional
probability of failure (CpF) characteristics of the equipment type. OC maintenance in concerned with
the characteristics of a specific failure type that could occur randomly throughout the equipment’s life.
Most failures do not occur instantaneously without warning signs preceding the event. OC tasks use
this fact to good effect because they rely on the identification of these warning signs - or potential
failures - before a functional failure occurs.

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