2. IN THIS PRESENTATION
1.MAINTENANCE
2.OBJECTIVE
3.GOAL
4.CHALLENGE TO INDUSTRY
5.MAITENANCE STRATEGY
6.REACTIVE MAINTENANCE--FAILURE BASED
7.PREVENTIVE MAINTENANCE- INTERVAL BASED
8.PREDICTIVE MAINTENANCE –CONDITION BASED
9.PROACTIVE MAINTENANCE
10.RELIABILITY CENTRED MAINTENANCE.
11.MAINTENANCE TECHNIQUES
12.PRINCIPLES OF MAINTAINABILITY DESIGN
3. 1.MAINTENANCE
Past & current maintenance practices in industry
would imply that maintenance is action associated
with equipment repair after it is broken.
The dictionary defines maintenance as follows:
“the work of keeping something in proper
condition; upkeep.”
This would imply that maintenance should be
actions taken to prevent a device or component
from failing or to repair normal equipment
degradation experienced with the operation of the
device to keep it in proper working order.
4. 2.OBJECTIVE
To Reduce unplanned downtime
To Extend machinery life
To Minimize Equipment damage/repairs
TO reduce Overtime
To Reduce repair cost
To Reduce parts inventory requirements
To Improve reliability
5. 3.GOAL
To preserve the functions of physical assets
throughout their technologically useful lives
To the satisfaction of their owners, of their users,
and of society as a whole .
By selecting and applying the most cost-
effective techniques
For managing failures and their consequences
With the active support of all the people involved.
6. 4.CHALLENGE TO INDUSTRY
Industries, are being pressured by competition, the
economy, regulatory branches, and other forces to
reduce operating and maintenance costs without
decreasing reliability or availability.
Plant Maintenance is generally ecognized as the
single largest controllable cost.
As a result, many Industries are being encouraged to
downsize their employee and budget levels.
This environment presents a challenge that is
management to reevaluate their maintenance
strategies.
8. 6.REACTIVE MAINTENANCE-
-FAILURE BASED
In the earlier part of this century most
maintenance resources were used to react to
equipment breakdowns that had caused major
operational losses.
From this practice the terms “reactive”,
“breakdown”, “corrective”, and “run-to-failure”
maintenance descriptions were coined for naming
the principal maintenance technique that formed
the maintenance strategy.
9. REACTIVE MAINTENANCE
Reactive Maintenance can be either good or bad.
When applying this maintenance technique,
maintenance, equipment repair, or replacement
occurs only when the deterioration in the condition of
the equipment causes a functional failure.
This type of maintenance assumes that failure is
equally likely to occur in any part, component, or
system and failure is age-related.
10. REACTIVE MAINTENANCE
This type of maintenance assumes that failure is
equally likely to occur in any part, component, or
system and failure is age-related.
Examples of components where Reactive
Maintenance is applicable are non-critical electric
motors less than 7.5 HP, comfort cooling, restroom
exhaust fans, small, low temperature water heaters,
and items where the consequences of failure are
negligible.
11. REACTIVE MAINTENANCE
Advantages
Lower initial cost,
Requires fewer staff
Disadvantages
Increased cost due to unplanned downtime of equipment.
Increased labor costs especially for untimely repairs and
replacements.
May result in secondary equipment or process damage.
May increased costs associated with repairs and replacements
Is an inefficient use of staff resources.
12. 7.PREVENTIVE MAINTENANCE-
-INTERVAL BASED
Preventive maintenance (PM) uses regularly
scheduled inspections, tests, services, repairs,
replacements, and other tasks to reduce the
frequency and impact of equipment failures.
These maintenance activities are performed on a
calendar or operating time interval basis to extend
the life of equipment and prevent premature
failure.
13. PREVENTIVE MAINTENANCE
Preventive maintenance is one of the first major
breakthroughs that resulted in a significant
reduction in maintenance costs, while
simultaneously resulting in an increase in
reliability and availability.
One of its benefits is the identification of the early
stages of equipment deterioration that, unless
remedied, would result in secondary damage at
failure.
14. PREVENTIVE MAINTENANCE
Preventive Maintenance schedules drawn on the
basis of manufacturer's (OEM) guidelines need to
be updated to specific requirements based on
utilities operational experience, equipment
behaviors & past data of similar utilities.
These schedules could be based on fixed time or
running hour’s basis depending upon service
conditions & criticality of requirement.
15. PREVENTIVE MAINTENANCE
For example, a common practice has been to
replace or renew bearings after a specified
number of operating hours, assuming that
bearing failure rate increases with time in
service.
Preventive maintenance is usually more
efficient than reactive maintenance.
16. PREVENTIVE MAINTENANCE
Advantages
Is cost effective in many capital intensive processes and
equipments.
Provides flexibility for the adjustment of maintenance periodicity.
Increases component life cycle.
Reduces equipment failures.
Results in an estimated 12% to 18% cost saving over that found
in a reactive maintenance program.
Disadvantages
Does not eliminate catastrophic failures.
Is more labor intensive.
Includes performing unneeded maintenance activities, which has
the potential to result in incidental damage to components.
17. 8.PREDICTIVE MAINTENANCE
-CONDITION -BASED
Predictive Maintenance (PDM) is a
systematic approach to determining the need
for equipment repair or replacement, and
limiting maintenance activities to only those
that are required to prevent costly major
repairs or unscheduled downtime.
18. PREDICTIVE MAINTENANCE
Various monitoring systems are used to
detect and analyze incipient faults.
Such conditions as temperature changes,
vibrations, insulation resistance
degradations, oil deteriorations, combustion
product releases, metallurgical
microstructure changes and many other
detectable indicators can provide an early
warning signal that failure is imminent unless
maintenance is performed.
19. PREDICTIVE MAINTENANCE
Predictive Maintenance is accomplished by combining
and using all available information: diagnostic and
performance data; maintenance histories; and
operations logs and design data to make timely
decisions about the maintenance requirements of
plant equipment .
The goals of predictive maintenance are to reduce
maintenance costs and to extend the effective
operating life of machinery through informed
engineering decisions.
20.
21. PREDICTIVE MAINTENANCE
Preventive Maintenance (PM) can be deferred if
PDM monitoring shows the PM procedure is not yet
necessary. This can lower the overall parts and
labor expenditures significant. (If it ain't broke, don't
fix it)
Equipment with indications of probable failure prior
to a scheduled PM activity can be identified and
scheduled for maintenance prior to failure. This
avoids unscheduled equipment downtime.
22. PREDICTIVE MAINTENANCE
Advantages
Provides increased component operational life and availability.
Allows for preemtive corrective actions
Results in decrease in equipment downtime
Lower costs for parts and labor.
Provides better product quality.
Improves worker and environment safety.
Raises worker morale.
Increases energy saving.
Results in an estimated 8% to 12% cost saving over that found in a
preventive maintenance program.
Disadvantages
Increases investment in diagnostic equipments
Increases investment in staff training.
23.
24. 9.PROACTIVE MAINTENANCE
Proactive is the opposite of Reactive.
Proactive maintenance is an activity performed to
detect and correct causes of failure i.e. actions
taken to correct conditions that could lead to
material degradation.
Instead of investigating material and performance
degradation factors to determine the extent of
incipient and impending failure conditions, proactive
maintenance concentrates on identifying and
correcting abnormal causes of failure that create
unstable operating conditions.
25. PROACTIVE MAINTENANCE
Proactive maintenance improves maintenance through better
design, installation, maintenance procedures, workmanship, and
scheduling.
The characteristics of proactive maintenance are:
Using feedback and communications to ensure that changes in
design or procedures are rapidly made available to designers
and managers.
Employing a life-cycle view of maintenance and supporting
functions.
Ensuring that nothing affecting maintenance occurs in isolation.
Employing a continuous process of improvement.
Optimizing and tailoring maintenance techniques and
technologies to each application.
Integrating functions that support maintenance into maintenance
program planning.
Using root-cause failure analysis and predictive analysis to
maximize maintenance effectiveness.
26. PROACTIVE MAINTENANCE
Proactive maintenance employs the following basic
techniques to extend machinery life:
Specifications for new/rebuilt equipment
Commissioning
Precision rebuild and installation
Failed-part analysis
Root-cause failure analysis
Reliability engineering
Rebuild certification/verification
Age Exploration (AE) and the relationship with Replacement
of Obsolete Items
Recurrence Control
27. PROACTIVE MAINTENANCE
Benefits:
• Providing enhanced utilization of available resources
• Avoiding unnecessary disruptions
• Ensuring objective problem solving
• Facilitating development of a comprehensive set of solutions
• Predicting other problems
• Identifying, assembling, and integrating contributory
circumstances
• Focusing on preventing recurrence, as well as providing
immediate corrective action
• Identifying improvement opportunities
Achieving these goals will provide the focus for corrective
actions.
28. 10. RELIABILITY CENTRED MAINTENACE
HISTORICAL EVOLUTION OF
RELIABILITY CENTRED MAINTENACE
In the case of aircraft it was also commonly
assumed that all reliability problems were directly
related to operating safety.
Over the years, However, it was found that many
types of failures could not be prevented no matter
how intensive the maintenance activities.
Moreover, in a field subject to rapidly expanding
technology it was becoming increasingly difficult
to eliminate uncertainty.
29. RELIABILITY BASED MAINTENANCE
Reliability-Centered Maintenance (RCM) integrates
Preventive Maintenance (PM), Predictive
maintenance and Proactive Maintenance to
increase the probability that a machine or
component will function in the required manner over
its design life-cycle with a minimum amount of
maintenance and downtime.
These principal maintenance strategies, rather than
being applied independently, are optimally
integrated to take advantage of their respective
strengths, and maximize facility and equipment
reliability while minimizing life-cycle costs.
30. RELIABILITY CENTRED MAINTENANCE
Advantages
Efficient.
Increased system reliability.
Lowered costs due to no unnecessary maintenance.
Minimized overhauls.
Reduced sudden equipment failures.
Maintenance focused on critical components.
Incorporates root cause analysis.
Disadvantages
Significant initial costs for training, and equipment.
Savings potential not readily seen by management.
31. 11.MAINTENANCE TECHNIQUES
Reactive maintenance comes naturally from the
need to repair failed equipment. However, the high
cost of repairs and the need for better reliability
stimulated the search for new ways to reduce failures.
Over the years, the analysis of equipment failures led
to the adoption of preventive maintenance
techniques that would prolong the mean time between
failures and enhance the probability that equipment
would be available when needed. These PM
practices, such as oil changing and periodic parts
replacement, lowered maintenance costs and
increased reliability.
32. MAINTENANCE TECHNIQUE
As the pressure grows to decrease maintenance costs
and make do with less resources, predictive
techniques that prescribe the minimum maintenance
at the right time are added to the strategy when a
failure indicator can be identified and monitored
economically.
Proactive maintenance is added as failure modes
are analyzed and causes can be identified and
eliminated.
Now, the plant maintenance strategy integrates the
use of corrective, preventive, predictive, and proactive
techniques as appropriate for specific equipment
33. Cost of Maintenance Programs (Piotrowski 2001)
in $per horse power per year
18
16
14
12
REACTIVE
10 PREVENTIVE
8 PREDICTIVE
6 RCM
4
2
0
35. 12.PRINCIPLES OF MAINTAINABILITY DESIGN
Great maintenance procedures cannot
overcome poor equipment design.
Every maintenance point should be
directly visible and fully accessible to the
maintainer.
Special tools are rarely available when
maintainers need them, so design all
maintenance tasks to eliminate the need for
special tools.
