Plant maintenance is an important service function of an
efficient production system.
It helps in maintaining and increasing the operational
efficiency of plant facilities.
Maintenance is the procedure of finding the faults in any
equipment/Machine and also removal of fault.
It may be before the breakdown or after the breakdown.
Plant maintenance usually refers to the methods, strategies,
and practices used to keep an industrial factory running
efficiently. This can include anything from regular checks of
equipment to make sure they are functioning properly.
The general aim of plant maintenance is to create a
productive working environment that is also safe for
To increase functional reliability of production facilities.
To maximize the useful life of the equipment.
To maximize production capacity from the given equipment.
To minimize the total production cost.
To minimize the frequency of interruption in production by
To enhance the safety of the manpower.
Importance of maintenance
It helps in identify the cause of failure , e.g whether the
failure is due to design defect, or a wear out failure.
It also helps in deciding the type of maintenance and
maintenance decision like replace and repair.
It provides the necessary information regarding the life and
reliability of the equipment.
With the help of this tool spare parts management got
In planned maintenance the maintenance action is carried out
with some fore thoughts, prior planning , record keeping and
control action. These can be further classified as :-
It is based upon the principle that ‘prevention is better than cure’.
It is a set of activities that are performed on plant equipment,
machinery, and systems before the occurrence of a failure in
order to protect them and to prevent or eliminate any
degradation in their operating conditions.
Or the maintenance carried out at predetermined intervals or
according to prescribed criteria and intended to reduce the
probability of failure or the degradation of the functioning and the
It has three types
Shut down maintenance
Running maintenance which includes those maintenance
activities that are carried out while the machine or
equipment is running.
Example – lubrication, adjustment of nuts and screws,
tightening of loose nut and bolts.
Scheduled Maintenance is any variety of scheduled
maintenance to an object or item of equipment.
Specifically, Planned Maintenance is a scheduled service visit
carried out by a competent and suitable agent, to ensure that
an item of equipment is operating correctly and to therefore
avoid any unscheduled breakdown and downtime.
Good example of PM program is car maintenance. After so
many kilometers or miles oil should be changed, parts
Shut Down Maintenance:
Which is a set of preventive maintenance activities
that are carried out when the production line is in
total stoppage situation.
These are performed generally after three or six
These involves the inspection of plant items which
are known or suspected to occur.
In this type, actions such as repair, replacement, or restore will be
carried out after the occurrence of a failure in order to eliminate the
source of this failure or reduce the frequency of its occurrence.
It also include the different types of actions like typical adjustment
of redesign equipment.
The difference between corrective maintenance and
preventive maintenance is that for the corrective
maintenance, the failure should occur before any corrective
action is taken.
It is of two types
1. Breakdown maintenance
2. Shutdown maintenance
It is an emergency based policy in which the plant or
equipment is operated until it fails and then it is brought back
into running condition by repair.
The maintenance staff locate any mechanical, electrical or
any other fault to correct it immediately.
It is feasible for the small factories where
1. There are few types of equipment.
2. Machine and equipments are simple and does not require any
3. Where sudden failure does not cause any serious financial
As the names implies it involves the prediction of the failure
before it occurs, identifying the root cause for those failures
symptoms and eliminating those causes before they result in
extensive damage of the equipment.
Type of maintenance performed continuously or at intervals
according to the requirements to diagnose and
monitor a condition or system. Also called condition based
Maintenance action which is carried out without any fore
thoughts or prior planning is called unplanned maintenance.
Emergency maintenance is one of the example of unplanned
In this type of maintenance the maintenance action is
executed with the help of all available maintenance resources
in least possible time, without any major time lag.
Examples are gas leakage in chemical plant, fire hazards,
breakdown of boiler, turbine etc.
General classification Maintenance problem.
Worn out bushes and bearings and other moving parts.
Fatigue of machine members
Creep of material at high temp
Excessive forced vibration, misalignments etc.
Overheating of the component
Lack of lubrication
Inadequate of cooling
Electrical insulation failure
Highly corrosive fluids containing abrasive particles
Failure of protective linings like glass , rubber etc.
Classification maintenance problem
based on time span:
Short run production problem
Maintenance problem which are carried out in a sort period of time
are known as short run production system. It may be hourly, daily
,weekly and monthly.
Hourly- inspection of correct lubricant, level of coolant, sharpness
of cutting tool.
Daily- cleaning of m/c, tightening of nuts, correct cooling,
inspection of various indicators, minor adjustment of parts.
Weekly- Major adjustment, lubrication, tightening of parts.
Monthly- checking for insulation, corrosion, safety guards,
checking of worn-out and distorted parts.
1. Job identification by preparing of
The very first step of PMP is to prepare the facility register
which defines that what to be maintained.
2. Preparation of maintenance schedule
In this step we prepare a maintenance schedule. It is simply a
comprehensive list of all the incident and their time of incidence.
It gives the useful information regarding the method, time and
place of maintenance work, besides it also provides secondary
information about maintenance man power requirement etc.
It gives the various details regarding maintenance like what, when,
3. Preparation of history card
It not only gives the useful information about the result of
maintenance events but also furnishes the essential details
regarding the uses of machines, free of failures and failure
4. Preparation of Job specification
In this step the job specification is prepared. It is simply a
document which provide the essential information regarding the
maintenance work to be done.
In general practice these job details are specifications compiled
from maintenance schedules.
They are a means of communicating the engineer’s requirement
to guide the workers.
They are prepared separately for each job.
5. Preparation of maintenance
It is a sequential list which allocates specific maintenance
work to a specific period.
In order to apply the job specification, the maintenance
programme is generally prepared for long run when the
machines/ equipment are to be inspected.
It is not a good practice because an industry can not prepare
a long run production well in advance since too many factors
arise and they will result into change in production and
It presents a overall picture of present and future
6. Preparation of weekly/Monthly
The next step under plant maintenance procedure is to
prepare the weekly/ Monthly maintenance programmes.
The maintenance programmes include the following topics.
1. Reconditioning or replacing the lubricating oil
2. Repairing and replacing worn out parts and tools etc
3. Checking all the electrical connections of the system
4. Checking the control system
5. Checking the performance of each parts.
6. Cleaning the interior parts like spark plugs, filters radiators,
crankcase, cylinders etc.
7. It will lie under the long run maintenance programmes.
7. Preparing of inspection report
This step is followed after the maintenance programme is
over. This is simply a document which furnishes the useful
information about the maintenance inspections which were
performed in the past.
8. Preparing of maintenance request
The next step under plant maintenance procedure is to
preparation of maintenance request. It is simply a document or
various maintenance suggestions and recommendation given by
the inspection report. Suggestions are the useful feedback
information that comes from users end workers.
9. Feedback mechanism
In the last step the application of corrective and control
actions are available on the basis of feedback mechanism.
These corrective actions should be applied to respective plant
facilities at the initial stage of maintenance planning or
Schedules of preventive maintenance:
It is simply a comprehensive list of all the incident and their
time of incident. It gives the following useful information
regarding the maintenance work.
i. What is to be done or maintained?
ii. How is to be maintained?
iii. When is to be maintained?
Besides this it may also provide the secondary information
regarding the place of maintenance and maintenance
Maintenance Strategy :
A maintenance strategy defines the rules for the sequence of
planned maintenance work. It contains general scheduling
information, and can therefore be assigned to as many
maintenance task lists (PM task lists) and maintenance plans
as required. A maintenance strategy contains maintenance
packages in which the following information is defined:
The cycle in which the individual work should be performed
(for example, every two months, every 3,106.86 miles,
every 500 operating hours)
Other data which affects scheduling
A maintenance strategy consists of:
Strategy header: Name of the strategy,
Scheduling parameters: Contain the scheduling data for
the respective maintenance strategy, which influence the
scheduling of maintenance plans.
Within a maintenance strategy, you can use different
scheduling indicators to specify the type of scheduling you
require or to define a cycle set:
Time-based (for example, every 30 days)
Time-based by key date (for example, every 30 days on the
30th day of the month)
Time-based by factory calendar (for example, every 30
Performance-based (for example, every 50 operating hours)
Total Productive Maintenance
Total productive maintenance (TPM) originated in Japan in
1971 as a method for improved machine availability through
better utilization of maintenance and production resources
It can be considered as the medical science of machines.
Total Productive Maintenance (TPM) is a maintenance
program which involves a newly defined concept for
maintaining plants and equipment.
The goal of the TPM program is to markedly increase
production while, at the same time, increasing employee
morale and job satisfaction.
TPM brings maintenance into focus as a
necessary and vitally important part of the
It is no longer regarded as a non-profit activity.
Down time for maintenance is scheduled as a
part of the manufacturing day and, in some
cases, as an integral part of the manufacturing
The goal is to hold emergency and unscheduled
maintenance to a minimum.
Why TPM :
TPM was introduced to achieve the following objectives.
The important ones are listed below.
Avoid wastage in a quickly changing economic environment.
Producing goods without reducing product quality.
Produce a low batch quantity at the earliest possible time.
Goods send to the customers must be non defective.
Today, with competition in industry at an all time high, TPM
may be the only thing that stands between success and total
failure for some companies.
It has been proven to be a program that works. It can be adapted
to work not only in industrial plants, but in construction,
building maintenance, transportation, and in a variety of other
If everyone involved in a TPM program does his or her part, an
unusually high rate of return compared to resources invested
may be expected.