RCM vs RA

Is RCM a form of Reliability Analysis (RA)? RA is the counting of failure and suspension events in order to understand the behavior pattern of  a component or failure mode. RCM practitioners sometimes refer to the Reliability Centered Maintenance (RCM) process as “reliability analysis”. However, this is confusing. RCM Analysis (as opposed to RA), precisely speaking, is a process to determine what scheduled tasks and one-time modifications should be done to preserve an item’s functions to the level required by its users. As such RCM will use the results of RA in addition to knowledge and consensus among subject matter experts to set up the scheduled program of preventive tasks, including CBM and one-time redesigns.

In other words, RA applies (data) “counting” techniques to determine failure behavior as a function of age and other significant variables. This behavior is then embodied in a “model” that is deployed for every-day decisions. RCM, on the other hand, is a process used to formulate what types of maintenance tasks should be applied generally and their frequencies. If, for example, RA has determined a good fit relationship between certain data variables and the failure probability of an item, RCM would use that information to recommend that CBM be applied to that item.

The Living RCM (LRCM) process makes the clear distinction between RCM and RA. RCM, tangibly, produces a knowledge base that describes all failure modes reasonably likely to impact safety and profitability and for each failure mode recommends a defensible maintenance strategy. As time goes on and experience accrues RA may be performed on a sample of work order instances of a given RCM failure mode of interest in order to better understand its age- and condition-based behavior. RCM, particularly living RCM, using the results of the RA study, will apply an updated strategy to better mitigate the consequences the failure mode.

© 2011 – 2015, Murray Wiseman. All rights reserved.