| There is a basic but very
real misconception concerning the roles of RCM (Reliability Centered Maintenance)
and RCA (Root Cause Analysis) in today's operating facility. This is due
primarily to the fact the most people think that the two programs do virtually
the same thing nothing could be further from the truth. Although both programs
are extremely beneficial if implemented properly, the purpose of each is
entirely different. When implemented together they compliment each other
and provide the greatest overall benefit to the facility.
The purpose of RCM is "to
determine the maintenance requirements of any physical assets (EQUIPMENT)
in its operating context."1
This is accomplished by answering seven questions about the equipment in
order to determine what type of maintenance strategy to employ for the
asset. RCM provides a flow diagram that tells you what type of maintenance
to use based on the answers to the questions. By answering the seven questions
all of the potential modes of failure are uncovered and a predictive maintenance
strategy is devised to mitigate the consequences of the failure based on
the criticality of the failure mode. In RCM, these failure modes are identified
as the root cause(s) of the failure. This is where the main difference
lies.
The purpose of RCA is "to
uncover the underlying reasons (root causes) why an event (not just equipment
but any type of event) is occurring so that the necessary steps can be
taken to eliminate the event in its entirety." This is accomplished
by analyzing the modes (the point at which RCM stops). RCA uses a logic
tree that stresses verification at every level. The advantage is that the
actual root causes that are uncovered are facts that have been derived
from the verification process. The comparison between the two programs
is striking -RCM is driven by preventive maintenance strategies while RCA
is driven by maintenance prevention strategies.
It should be clear that the
difference between RCM and RCA is that RCM treats the symptom while RCA
finds and corrects the cause. For example, consider a person who has chronic
headaches for some unknown reason. RCM would analyze all the possible reasons
or modes (stress, disease, allergies, loud noise, bright light, lack of
rest, etc.) that this person was having headaches. RCM would then tell
this person to do anything from taking aspirin to performing more complicated
forms of treatments, at designated intervals, in order to mitigate the
consequences of the headache in its primary state. By comparison, RCA would
uncover the reasons why the headache is recurring and provide resolutions
for its complete elimination. Both techniques would solve the immediate
problem of headache pain, but only RCA would uncover and eliminate the
actual cause of the headache.
The question becomes what
is important to your facility. Do you want to take pills to relieve the
symptoms of your headaches (failures), or do you want to eliminate the
headaches in their entirety!
1 - Reliability-centered
Maintenance published by Industrial Press Inc. (D, New York, New York 1992)
? It is available on this site at http://www.maintenanceresources.com/Bookstore/MaintenanceManagement/Reliability.htm |
