Machinery Maintenance, maintenance types, breakdown maintenance, preventive maintenance, predictive maintenance

1. Predictive Maintenance
Vs
Preventive Maintenance
Mohammud Hanif Dewan
Marine Chief Engineer and Lecturer

2. Specific Learning Objective
 Maintenance and it’s types
 Breakdown maintenance
 Preventive Maintenance
 Predictive Maintenance
 Preventive maintenance Vs Predictive
maintenance
 Predictive maintenance in marine vessels

3. What is Maintenance?
The technical meaning of
“maintenance” involves
functional checks,
servicing, repairing or
replacing of necessary
devices, equipment,
machinery and supporting
utilities in industrial and
residential installations.

4. Objectives of Maintenance
Minimize loss of productive time
Minimize repair time & cost
Keep productive assets in working
condition
Minimize accidents
Minimize total maintenance cost
Improve quality of products

5. Types of Maintenance
There are main 3 types of Maintenances:
1. Breakdown maintenance or
reactive maintenance
2. Preventive maintenance or
planned maintenance
3. Predictive maintenance or
condition-based maintenance

6. Breakdown maintenance
 It is performed when a machine
part breaks down suddenly.
 It becomes a repair work
 Since there is no plan for the
machinery maintenance works, to
control the maintenance cost is
not possible in this type of
maintenance.
 It is not suitable for marine
vessels
 For example, replacing the engine
system lub oil when it is fully
contaminated or degraded

7. Breakdown maintenance
Advantages
 Low cost
 Less manpower
Disadvantages
 Increased cost due to unplanned downtime of equipment
 Cost involved with repair or replacement of equipment.
 Inefficient use of staff resources.

8. Preventive Maintenance
 It is performed regularly on a
machinery as a Planned
Maintenance System (PMS) to
lessen machinery failure
 It is performed while the machine
is still working and so avoid
unexpected breakdown of
machinery.
 It’s safe but maintenance cost is
very high.
 For example, replacing the engine
system lub oil after completion of
running hours according to PMS/
maker’s instruction

9. Preventive Maintenance
There are few basic activities associated with
preventive maintenance:
 Inspections: damage, alignment, leaks, cracks, etc.
 Servicing: alignment, clearing or replacing filters, and
verifying sensor operation
 Lubrication: topping off oils or other fluids and at times
flushing and replacing the fluid
 Fastening: Periodical checks for fastening system for
its proper location and alignment.

10. Preventive Maintenance (PM)
Figure: Flow Chart of Preventive Maintenance

11. Preventive Maintenance (PM)
Advantages:
 Cost effective during the capital investment processes.
 Increased component life
 Energy savings
 Reduces equipment or process failure
 Estimated 12% to 18% cost savings over breakdown
maintenance program [2]
Disadvantages:
 Catastrophic failures still likely to occur due to lack of
condition monitoring
 Labor intensive
 Potential for dropping of performance for unneeded
maintenance.
 Potential for incidental damage to components
during conducting unneeded maintenance

12. Predictive Maintenance
 It’s an advanced scientific technique
to maximize operating time and
minimize unnecessary work.
 Conditions of the machinery can be
measured continuously and this
enables the maintenance team to
plan for an overhauling.
 In this maintenance lab analysis
method, sensitive instruments and
computerized control system are
used to predict troubles.
 For example, replacing the engine
system lub oil on basis of laboratory
analysis report and instructions

13. Predictive Maintenance
It monitors the condition of equipment or systems to
detect/trend the degradation. Techniques include:
1. Vibration monitoring
2. Thermographic inspection
3. Oil analysis
4. Visual inspection
5. Ultrasonic leak detectors
6. Electrical insulation:
A. Megger tests
B. Surge comparison
8. Performance testing
9. Wear and dimensional measurements
10. Nondestructive testing
A. Ultrasonic
B. Borescope inspections
C. Eddy current performance

14. Predictive Maintenance
Figure: Flow Chart of Predictive Maintenance

15. Predictive Maintenance
Advantages
 Increased component operational life/availability
 Allows for preemptive corrective actions
 Decrease in machinery downtime
 Decrease in costs for parts and labor
 Better product quality
 Improved worker and environmental safety
 Improved worker morale
 Energy savings
 Estimated 25% to 30% cost savings over breakdown
maintenance and 8% to 12% over preventive
maintenance
Disadvantages
 Increased investment in diagnostic equipment.
 Increased investment in staff training.

16. Preventive Maintenance Vs Predictive Maintenance
Preventive maintenance Predictive maintenance
Definition
Preventive maintenance is
performed on a regular,
predetermined schedule
Predictive maintenance is done
only when needed based on real
time conditions of machinery
Trigger Time, meter reading and usage Condition
Investment
Cost
Low Medium/High
Cost Savings 12% to 18% [2] 25% to 30% [2]
Resources
Needed
 Maintenance software
 Maintenance scheduler
 Preventive maintenance
checklists
 CMMS
 Maintenance scheduler
 Condition monitoring software
 Condition monitoring tools and
sensors
 PdM training
Pros  Better than reactive
maintenance or breakdown
maintenance
 Relatively easy to implement
 Maintenance is performed as
needed
 Reduces maximum amount of
downtime
Cons  Risk of over-maintaining
 Labor intensive (not
performed as needed)
 Expensive technology needs
purchased
 Time-intensive to implement
correctly

17. Preventive Maintenance Vs Predictive Maintenance
Preventive Maintenance (Time-Based Maintenance)
Basic philosophy
 Schedule maintenance activities at predetermined time intervals.
 Repair or replace damaged equipment before obvious problems occur.
 Cost: $13/hp/yr
Predictive Maintenance (Condition-Based Maintenance)
Basic philosophy
 Schedule maintenance activities when mechanical or operational
conditions warrant.
 Repair or replace damaged equipment before obvious problems occur.
 Cost: $9/hp/yr
Source: Pro-Active Maintenance for Pumps (Piotrowski, 2001)

18. Predictive Maintenance in Marine Vessels
Predictive maintenance is the most modern maintenance system
that should be followed in marine vessels. Because:
1. Preventive maintenance only occurs in accordance with a
program’s schedule. Whereas, predictive maintenance
technologies continuously monitor in-service equipment, and let
crewmembers know when a component needs attention before it
fails. For example,
Maintenance Tasks Preventive Maintenance Predictive Maintenance
Renewing Engine Lub Oil According to running
hours as instructed in
PMS/Maker’s Manual
According to lab analysis
report and instructed in
lab test report.
Overhauling Deck Machinery According to time
duration as instructed in
PMS/ Maker’s Manual
According to CMMS report
/ Condition analysis
Over hauling of Diesel
Generator / Main Engine
According to running
hours as instructed in
PMS/Maker’s Manual
According to CMMS report
/ Condition analysis

19. Predictive Maintenance in Marine Vessels
Additional benefits include:
 Knowing what parts to stock in advance
 Reduced overhead costs
 Energy savings
 Overall efficiency improvements
 Reduced maintenance and repair costs
 Improved productivity
 Rate of component failures is very less

20. References
1. Maintenance, P. (n.d.). Preventive and Predictive Maintenance, 1–23.
https://www.lce.com/pdfs/The-PMPdM-Program-124.pdf
2. Types of Maintenance Programs by the Department of Energy, O&M Best
Practices Guide, Release 3.0
https://www1.eere.energy.gov/femp/pdfs/OM_5.pdf
3. https://www.onupkeep.com/learning/maintenance-types/preventive-
predictive
4. https://accendoreliability.com/preventive-maintenance-or-pm-goals-and-
activities/
5. https://www.marineinsight.com/tech/predictive-maintenance-on-board-ships/
6. https://www.fiixsoftware.com/blog/preventive-maintenance-top-priority/
7. Gkerekos, Christos & Lazakis, Iraklis & Theotokatos, Gerasimos. (2017).
Ship machinery condition monitoring using performance data through
supervised learning.
8. Piotrowski, J. April 2, 2001. Pro-Active Maintenance for Pumps, Archives, February
2001, Pump-Zone.com [Report online]. Available URL: http://www.pump-
zone.com. Reprinted with permission of Pump-Zone.com.

21. Any Question?
Thankyou!