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Regardless
of how a maintenance program has been developed, there
is a constant need to review and update the program
based on failure history, changing operating
circumstances and the advent of new predictive
maintenance technologies.
The generic process used to perform such
analyses is known as PM Optimization (PMO).
PMO has been performed, no doubt, since the
world became mechanized and humans realized the
benefits of performing preventive maintenance.
PMO as a technique has been refined to reflect
the RCM decision logic since the formulation of RCM in
1978.
There
are a number of methods that have been created under
the acronym PMO.
One of these has been applied in the US Nuclear
power industry for over 8 years and has been
recognized as a major benefit by the North
American Nuclear Regulatory Commission¹.
Each
of the PMO methods has differences and there is no
accepted standard for PMO.
Discussions contained in this paper are
therefore, based on the method of PMO known as PMO2000.
Some of the comments and comparisons made between PMO
and other methods may not apply to methods of PMO.
The PMO2000 process has
been developed over a five-year period by OMCS
with the assistance of several Australian Companies.
There are now 12 users of PMO2000 in the Australia
Pacific Region. The PMO2000 process is endorsed by SIRF
Roundtables Ltd and is the global maintenance
analysis tool of choice for one of the world’s
largest mining companies. PMO2000 is the intellectual
property of OMCS.
The methodology is described in detail in Part
1.
According
to the standard SAEJA1011, any RCM program should
ensure that all of the following seven questions are
answered satisfactorily and are answered in the
sequence shown:
1.
What are the functions and associated desired
standards of performance of the asset in its present
operating context (functions)?
2.
In what ways can it fail to fulfill its
functions (functional failures)?
3.
What causes each functional failure (failure
modes)?
4.
What happens when each failure occurs (failure
effects)?
5.
In what way dose each failure matter (failure
consequences)?
6.
What should be done to predict or prevent each
failure (proactive tasks and task intervals)?
7.
What should be done if a suitable proactive
task cannot be found (default actions)?
What is PM
Optimization
The questions answered
in completing a PMO2000 analysis are as follows:
1) What maintenance
tasks are being undertaken by the operations and
maintenance personnel (task compilation)?
2) What are the failure
modes associated with the plant being examined
(failure mode analysis)?
a) What is (are) the
failure mode(s) that each existing task is meant to
prevent or detect
b) What other failure
modes have occurred in the past that have not been
listed or have not occurred and could give rise to a
hazardous situation.
3) What functions would
be lost if each failure were to occur unexpectedly
(functions)? [optional question]
4) What happens when
each failure occurs (failure effects)?
5) In what way does
each failure matter (failure consequences)?
6) What should be done
to predict or prevent each failure (proactive tasks
and task intervals)?
7) What should be done
if a suitable proactive task cannot be found (default
actions)?
The complete PMO2000
methodology has nine steps. The seven questions listed
above are a subset of the complete PMO2000
methodology. The additional steps in PMO2000 not
listed above are as follows:
- Grouping and Review
- Approval and
Implementation
- Living Program
These final three steps
are necessary to implement the analysis outputs and
ensure that the PMO analysis does not stop once the
first review has been completed. These steps are not
considered relevant to this paper as it is assumed
that RCM analysis must also perform these steps to
ensure a successful outcome. RCM and PMO are
considered identical in this regard.
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¹ Johnson
1995 |
