MAINTENANCE ENGINEERING & MANAGEMENT

A schematic of the decision process in selecting an
appropriate maintenance strategy / technique:-

overview detail comments

What are Tasks or procedures designed to Detect
maintenance establish serviceability Inspect
techniques? Repair/restore
Exchange
Re-design

Why do we Match technique to failure Historic information
choose mode and criticality Failure mode analysis

particular Select appropriate (FMEA)(FMECA)
maintenance maintenance strategy
On failure
technique? Feasibility of application of Time based (Cyclical)
maintenance technique
On condition
Design out
Opportunity

Simplest technique
Safe to implement
physically possible

Confidence in
technique

Cost effective
Training requirements

Maintenance STRATEGIES

 A schematic of the decision process in selecting an appropriate
maintenance strategy in practice the best way is to look down over few
steps:-

 Prepare for the analysis
 Select the equipment to be analyzed
 Identify functions
 Identify functional failure
 Identify and evaluate (categories) the effects of failure
 Identify the causes of failure
 Select maintenance tasks

Maintenance STRATEGIES

2.2.3 System Approach to maintenance Functions

 Identification of the needs of maintenance related activities, which may include
repair, reconditioning or replacement of components.

 Analyzing the requirement of the above needs.

 Determining the functional procedures for maintenance task selection. Work
planning and scheduling, work order processing etc

 Outlining the report and controlling procedure of all maintenance related
activities

 Development of supporting services and infrastructure for efficient execution of
maintenance functions

 Determining the cost account procedures for optimizing maintenance related
expenditures

 Adopting a policy for training of maintenance staff and assurance of quality.

Maintenance STRATEGIES

2.3 TYPES OF MAINTENANCE

 There are many types of maintenance.
 Maintenance is an action necessary for retaining or restoring a

piece of equipment, machine or system to the specified
operable condition to achieve its maximum useful life

Maintenance STRATEGIES

2.3.1 Categorization of types of maintenance based on
functions and advantages

i.

ii.

iii.

iv
)
v

vi

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 A. breakdown maintenance

 Involves the repair or replacement of equipment and components after
they have failed.

 Management strategy can be contrasted with preventive and predictive
maintenance, which are designed to avoid equipment failure.

 When the machinery fail. Considerable expense is required to allocate
manpower on an emergency basis, repair/replacement parts, lost
revenues due to non-production can mount rapidly depending upon the
manufacturing process or product.

 Clearly these method has the highest associated cost and maintenance is
unpredictable at best.

 In addiction, an unexpected failure can be dangerous to personnel and
facility.

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 A. breakdown maintenance

 The key to managing an effective breakdown is implementing efficient
stock and inventory management procedures.

 Management must monitors the asset manufacturer’s guidelines, parts
inventories and backlog history to determine which equipment parts should
always kept on-premises for a rainy day.

 There are 2 main types of breakdown maintenance:

 i. Run-to-failure maintenance
 Ii. Emergency maintenance

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

There are 2 main types of breakdown maintenance:
i. Run-to-failure maintenance (PLANNED)

- Refer to equipment failure that is expected to happen. Ideal conditions
for this include assets that are; easy to replace and won’t jeopardize
operational system or personal safety.

i. Emergency maintenance (UNPLANNED)
- is conducted when an important piece of equipment stops working
unexpectedly and needs to be replaced immediately. These normally
associated with expensive costs, financial losses and safety hazards.
Disadvantages; the companies will overspend of needed parts,
outsourced technician assistance and overtime costs.



THE PROS AND CONS OF BREAKDOWN
MAINTENANCE

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 B. corrective maintenance

 Is a form of system maintenance which is performed after a fault or
problem emerges in a system, with the goal of restoring operability to the
system.

 It is a maintenance task perform to identify, isolate and rectify a fault so
that the failed equipment, machine or system can be restored to an
operational condition within the tolerances or limits established for in-
service operations.

 The process of corrective maintenance begins with the failure and
diagnosis of the failure to determine why the failure appeared.

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

Diagnostic
process
include

• Physical inspection of a system
• The use of a diagnostic

computer to evaluate the
system
• Interview with system users



EXAMPLES OF CORRECTIVE MAINTENANCE

It may be performed on a wide
Variety of equipment, systems and
Processes.

Here are a few examples;





advantages disadvantages

 Lower costs  Unpredictability
 Simple process  Interruption to production
 Inspection opportunity  Shorten asset lifespan.





2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 C. preventive maintenance

 Is a predetermined work performed to a schedule with the aim of
preventing the wear and tear or sudden failure of equipment components

 It helps to:-

 Protect assets and prolong the useful life of production equipment
 Improve system reliability
 Decrease cost of replacement
 Decrease system downtime
 Reduce injury

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

Preventive maintenance function should incorporate the following
elements:-

 Reliability of components
 Maintaining equipment service records
 Scheduling replacement of components at the end of their useful service

life
 Acquiring and maintain inventories of least reliable component, critical

component and components schedule for replacements
 Replacing service-prone, equipment with more reliable performer

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages



The pros and cons of preventive maintenance

Pros Cons

 Enhanced safety  Budgetary constraints
 Longer equipment lifespan  More resources required
 Increased productivity  Time consuming
 Reduced costs  Tricky to organize
 Less energy consumption

Types of Preventive Maintenance

Periodic
maintenance

Prescriptive 4 primary Meter-based
maintenance categories maintenance

Predictive
maintenance



Example of preventive maintenance



Example of preventive maintenance



2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 D. Predictive maintenance (PdM)

 Is the most misunderstood and misused of the entire plant improvement
program.

 Users define it as:-

 To prevent catastrophic failure of critical rotating machinery
 Maintenance scheduling tool that uses vibration and infra red or lubricating oil

analysis data to determine the need for corrective maintenance action.

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 D. Predictive maintenance (PdM)

 This approach offers cost savings over routine or time-based preventive
maintenance, because tasks are performed only when warranted

 The main value of (PdM) is to allow convenient scheduling of corrective
maintenance, and to prevent unexpected equipment failures.

 The key is “ the right information is the right time”.

 By knowing which equipment needs maintenance, maintenance work can
be better planned, and what would have been ‘unplanned stop’ are transfer
to shorter and fewer ‘planned stops’ thus increasing plant availability.

 It also can increase equipment lifetime, increase plant safety, fewer
accidents with negative impact on environment, and optimized spare
parts handling.

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 D. Predictive maintenance (PdM)

 The ultimate gal is to perform maintenance at a scheduled point in time
when the maintenance activity is most cost-effective and before the
equipment loses performance within a threshold.

 Most PdM inspections are performed while equipment is in service, thereby
minimizing disruption of normal system operations.

 Adoption PdM can result in substantial cost saving and higher system
reliability

PdM Process2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

Set up

test

Monitor

Repair
Schedule repair

before failure
Make the repair

Inspection
schedules

 Advantages of PdM

 Increased equipment lifetime
 Increased plant safety
 Fewer accidents with negative impact on environment
 Optimized spare part handling

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 E. Reliability Centered maintenance (RCM)

 It is a process to ensure that assets continue to do what their users require in
their present operating context.

 Its generally used to achieve improvement in fields such as the
establishment of safe minimum levels of maintenance, changes to
operating procedures and strategies, also the establishment of capital
maintenance regimes and plans.

 Successful of RCM will lead to increase in cost effectiveness, machine
uptime, and a greater understanding of the level of risk that the
organization is managing.

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 Primary principle of reliability centered maintenance (RCM)

 Function oriented. It seeks to preserve system or equipment function
 Device group focused.
 Reliability centered.
 Acknowledges designs limitations.
 Driven by safety and economics.
 Defines failure as any unsatisfactory condition.
 Uses a logic tree to screen maintenance tasks.
 Tasks must be applicable
 Tasks must be effective
 Acknowledges two types of maintenance tasks and run-to-failure.
 a living system

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 Required analysis

 Using RCM develops maintenance standards for ensuring that a system or
device meets its designed reliability or availability.

RCM determines maintenance requirements by considering the following
questions:-

i. What does the device/system do?
ii. What is its function?
iii. What failure are likely to occur?
iv. What are the likely consequences of failure?
v. What can be done to reduce the probability of the failure, identify the

onset of failure, or reduce the consequences of the failure?

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 Failure

 Is the cessation of proper function or performance.
 It can examine failure at device group level, system level, component

level, and sometimes evens the parts level.
 The maintenance approach must be based on a clear understanding of

the consequences of failure at each level.

 Identify the functions
 Identify failures
 Identify the consequences of failure
 Identify the failure process

2.3.1 Categorization of Types of Maintenance
Based On Functions & Advantages

 F. Reactive maintenance

 It is also referred to as breakdown, repair, fix-when-fail, or run-to-failure (RTF)
maintenance.

 When applying this technique, maintenance, equipment repair or
replacement occur only when the deterioration in an equipment condition
causes a functional failure.

 This type of maintenance assumes that failure is equally likely to occur in
any part, component or system.

 A purely reactive maintenance program ignores many opportunities to
influence equipment survivability.

 On the other hand, reactive maintenance can be used effectively when it
is performed as a conscious decision based on the results of RCM analysis
that compare the risk and cost of failure with the cost of maintenance
required.

2.3.2 Methods for Each of Maintenance
Suitable in Industries & Processes

2.3.2.1 Condition Based Maintenance (CBM)

 Methodology

 Maintenance when need arises. Is performed after one or more indicators show
that equipment is going to fail or that equipment performance is deteriorating.

 A technique closely related to PDM that involves monitoring machine condition
and predicting machine failure.

 The concept that applicable to mission critical system that incorporate active
redundancy and fault reporting. Its also applicable to non-mission critical system
that lack redundancy and fault reporting

 Is based on using real-time data to prioritize and optimize maintenance
resources. Observing the state of the system is known as condition monitoring.

 The system will determine the equipment’s health and act only when
maintenance is actually necessary.

2.3.2 Methods for Each of Maintenance
Suitable in Industries & Processes

2.3.2.1 Condition Based Maintenance (CBM)
 Methodology (…smbg)

 Ideally condition-based maintenance will allow the maintenance personnel to do
only right things, minimizing spare parts cost, system downtime and time spent on
maintenance.

2.3.2 Methods for Each of Maintenance
Suitable in Industries & Processes

2.3.2.1 Condition Based Maintenance (CBM)
 Advantages

 Improved system reliability
 Decreased maintenance costs
 Decreased number of maintenance operation causes a reduction of human

error influences.

2.3.2 Methods for Each of Maintenance
Suitable in Industries & Processes

2.3.2.1 Condition Based Maintenance (CBM)
 Disadvantages

 High installation costs, for minor equipment items often more than the value of the
equipment

 Unpredictable maintenance periods cause costs to be divided unequally
 Increased number of parts the need maintenance and checking.

2.3.2 Methods for Each of Maintenance
Suitable in Industries & Processes

2.3.2.2 Risk Based maintenance (RBM)

 Is opportunity for incremental improvement by eliminating low value tasks
and introducing tasks that address high commercial risk areas.

 It evaluate the current commercial risk and analyzes the costs and benefits
of steps to mitigate failure.

 The purpose is to develop and manage inspection and maintenance plain
for new and existing assets.

2.3.2 Methods for Each of Maintenance
Suitable in Industries & Processes

2.3.2.2 Risk Based maintenance (RBM)
Benefits:-
 Increased revenue due to higher uptime, a pro-active maintenance and

inspection strategy and execution plans.
 Increased operating results as operation, maintenance and inspection

costs shrink.
 Longer asset life and lower costs for fixed asset replacement
 Less working capital needed due to better planning and cash-flow

management

2.3.2 Methods for Each of Maintenance
Suitable in Industries & Processes

2.3.2.2 Risk Based maintenance (RBM)
Factors for implementations:-
 Size of prize and ate of return depend on start point
 Most problems have many possible solutions

Asset risk solution risk

Sustainable implementation NO

Common pitfalls:
A common approach – inefficient and inappropriate:

Situational analysis to decide what to improve

Select solution

Solution is unworkable so rework based on feedback

YES

Common pitfalls:
A common approach – inefficient and inappropriate:

Situational analysis to decide what to improve –
including analysis of implementation factors

Select optimum solution

2.4 Total Productive Maintenance (TPM)

 To be success, organizations must be supported by both effective and
efficient maintenance practices and procedures.

 The global marketplace has necessitated many organization to implement
proactive lean manufacturing programs and organizational structure to
enhance their competitiveness.

 TPM is one of the approach to improving the performance of maintenance
activities to develop and implement strategy.

 TPM implementation methodology provides organizations with guidelines to
transform fundamentally their shop-floor by integrating culture, process and
technology.

2.4 Total Productive Maintenance (TPM)

Total: signifies to consider every aspect and involving everybody from
Productive: top to bottom
Maintenance:
emphasis on trying to do it while production goes on and
minimize trouble for production; and

mean equipment upkeep autonomously by production operators
in good condition – repair, clean, grease and accept to spend
necessary time on it.