“to make as effective, perfect, or useful as possible.”
optimization
two things happened in the maintenance world which have changed its very soul
forever.
The maintenance world was that the reliability and availability of existing plants and equipment had to
increase.
The resource-intensive philosophy of Preserve Equipment had to change
(4) serious problems on why Preserve Equipment mindset is flawed:
Inadvertently promoted an environment where everything was equally important.
Created an environment where decisions were made to perform maintenance simply because there was an
opportunity to do so.
We were overly conservative on our maintenance actions, actually doing more than was necessary in
some instances.
as the downsizing syndrome set in, the Preserve Equipment principle really overwhelmed us because we
couldn’t keep up with everything.
generally asserts that a minority of causes, inputs, or efforts usually lead to
a majority of the results, output, or rewards.
80/20 rule
is a systematic methodology used to identify the preventive maintenance– related tasks
necessary for realizing the inherent reliability of equipment at the lowest cost.
RELIABILITY CENTERED MAINTENANCE
RCM GOALS
To establish design-related priorities that can facilitate preventive maintenance in an
effective manner
To plan preventive maintenance tasks that can reinstate safety and reliability to their original
levels in the event of system or equipment deterioration
To gather the data necessary for design improvement of items with proven unsatisfactory
original reliability
To accomplish the above three goals with minimal total cost (i.e., including the cost of
residual failures and the maintenance cost).
PRINCIPLES OF RCM
1.RCM is equipment/system focused
2.RCM acknowledges
three types of maintenance
tasks along with
run-to-failure (failure finding, time directed, condition directed)
3.RCM uses a logic tree
for screening maintenance
tasks
4.RCM acknowledges
design limitations
5.RCM task must be
applied
6.RCM is a living system
7.RCM is driven by
safety and economics
8.RCM is reliability
centered
9.RCM defines
unsatisfactory conditions
as failure
10.RCM tasks must be
effective
11.RCM is function
oriented
THE MINIMUM CRITERIA BEGINS
WITH ASKING THE FOLLOWING
SEVEN QUESTIONS
What are the functions and associated standards of the asset performance in its current
operating context?
In what ways does it fail to meet its assigned functions?
What are the specific causes for each functional failure?
What are the specific effects of each malfunction or failure?
In what specific way does each failure or malfunction matter?
What possible actions can be taken to predict or prevent the occurrence of each failure?
What measures can be exercised in the event of not finding a suitable proactive task?
The consequence of failure (which could include
degradation) is evaluated at the first level (Figure 3.2).
Note: The analysis should not proceed through the first
level unless there is a full and complete understanding of
the particular functional failure.
First Level Analysis (Determination of Effects)
Applying the decision logic of the first level questions to
each functional failure leads to one of five effect categories
Second Level Analysis (Effects Categories)
KEY RCM PROGRAM ELEMENTS
reactive maintenance, predictive maintenance, proactive maintenance, and
preventive maintenance
When using this maintenance method, item and equipment
repair, maintenance, and replacement occur only when the
degradation in the condition of an item or equipment leads to
a functional failure.
This type of maintenance assumes that there is an equal
chance of malfunction or failure in any component, part, or
system.
When only this type of maintenance is practiced, a high
percentage of unplanned maintenance-related activities, poor
use of maintenance effort, and high replacement part
inventories
REACTIVE MAINTENANCE
TYPES OF CORRECTIVE
MAINTENANCE
Fail repair, overhaul, slavage, servicing, rebuild
This is concerned with restoring the failed item or equipment to its operational state.
Fail repair
This is concerned with repairing or restoring an item or equipment to its complete
serviceable state meeting requirements outlined in maintenance serviceability standards, using the
“inspect and repair only as appropriate” method.
Overhaul
This is concerned with the disposal of nonrepairable materials and utilization of salvaged
materials from items that cannot be repaired in the overhaul, repair, or rebuild programs.
Salvage
This type of corrective maintenance may be required because of a corrective
maintenance action; for example, engine repair can result in requirement for crankcase refill,
welding on, and so on.
Servicing:
This is concerned with restoring an item or equipment to a standard as close as possible to
its original state with respect to appearance, perfor mance, and life expectancy.
Rebuild:
is the performance of inspection and/or servicing tasks that have
been preplanned (i.e., scheduled) for accomplishment at specific points in time to retain the
functional capabilities of operating equipment or systems.
also known as time-driven or interval-based maintenance and
is carried out without any regard to equipment condition.
Preventive Maintenance
Preventive Maintenance Task categories:
Time-directed (TD): aimed directly at failure prevention or retardation.
Condition-directed (CD): aimed at detecting the onset of a failure or failure symptom.
Failure-finding (FF): aimed at discovering a hidden failure before an operational demand.
Run-to-failure (RTF): a deliberate decision to run to failure because the others are not possible
or the economics are less favorable.
ELEMENTS OF PREVENTIVE
MAINTENANCE
Inspection
Calibration
testing
adjustment
servicing
installation
alignment
Periodically inspecting items to determine their serviceability by comparing
their physical, mechanical, electrical, and other characteristics to established standards
inspection
Detecting and adjusting any discrepancy in the accuracy of the material or
parameter being compared to the established standard value
calibration
Periodically testing to determine serviceability and detect mechanical or electrical
degradation
Testing
