Day 1- Part 1- Understanding Maintenance (Short) - Updated 10-10-2014.pdf

8/19/2019 Day 1- Part 1- Understanding Maintenance (Short) - Updated 10-10-2014.pdf

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Fundamentals/Philosophy ofReliability CenteredMaintenancePrepared by :Eng. Mohamed Refaat AbdelMeguid

October, 2014

1


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Day 1 Agenda:

Introduction to Maintenance

• Understanding Maintenance,

• Maintenance Goals and Objectives,

• Maintenance Cost,

• Terms and Definitions,

•

History,• Policies,

• Classifications.


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Equipment Failure Process

• Definition,

• Why Equipment Fails,

• Machinery Failure Patterns andCharacteristics,

• Bathtub Curves,

• Causes of Failure.

• Physical failures,

• Human errors and latent causes.

Day 1 Agenda :


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Preventive Maintenance

• PM Philosophy,

• PM Risk,

• PM CLAIR Activities,

• Lubrication,

• Advantage and Disadvantages,

PM Optimization,

Day 1 Agenda:


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What maintenance is?

If this question is asked, words like fix, restore,replace, recondition, and rebuild will be repeated.

However, to key the definition of maintenance tothese words is to miss understanding maintenance.

Maintenance is the act of maintaining. The basis formaintaining is to keep, preserve, and protect. That is

to keep in an existing state or preserve from failureor decline.

Understanding Maintenance


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Maintenance is defined as the combination of activities bywhich equipment or a system is kept in, or restored to, astate in which it can perform its designated function.



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Work

undertaken

All activities (information, analysis, repair,

etc.)

To keep Planned maintenance (Preventive,Predictive and proactive policy)

To restore Unplanned maintenance

Facility System level (equipment, unit, plant)

Acceptablestandard level

Acceptable level at certain workingcondition

According to BS3811

Maintenance is the work undertaken in order to keep orrestore a facility to an acceptable standard level.



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According to the European Standard EN 13306,maintenance concerns the "combination of all technical,administrative and managerial actions during the life cycle

of an item intended to retain it in, or restore it to, a state inwhich it can perform the required function".



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Maintenance is a profession devoted to keep the Industryrunning in the best possible shape, making equipmentreliable, productive, and secure to operate.

(It means Keep it Going, it does not onlymean Repair!)



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Organizations’ Objectives include:

• Meet customer satisfaction

• Maximizing profit

• Meet deliveries

• Meet set safety standard

•

Zero product defect

Does Maintenance affect these goals?



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Maintenance is the backbone of all successful enterprises

and contributes to:

• Improve product quality

• Reduce costs

• Meet set targets

• Improve utilization

• Improve equipment performance



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The maintenance organization in a company probably has

one of the most important functions, looking after assets

and keeping track of equipment in order to secure

productivity. With no or a poor maintenance organization a

company will loose a lot of money due to lost production

capacity, cost of keeping spare parts, quality deficiencies,

damages for absent or late deliveries etc.



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Perhaps more important is the fact that

ineffective maintenance management

significantly affects the ability to

manufacture quality products that are

competitive in the world market. The

losses of production time and product

quality that result from poor or inadequate

maintenance management have had a

dramatic impact on the ability to compete

with others.



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Maintenance OrganizationObjectives


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The principal responsibility of maintenance is to providea service to enable an organization to achieve itsobjectives, they generally include the following:

• Maximum production• Identify and implement cost reductions• Provide accurate equipment maintenance records• Collect necessary maintenance cost information• Optimize maintenance resources

• Optimize capital equipment life• Minimize energy usage• Minimize inventory on hand

Maintenance Organization Objectives


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Maximize Production• Maximize production at the lowest cost, the highest

quality, and within the optimum safety standards.


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Identify and implement cost reductions

A maintenance organization can help a companyreduce costs in many ways. For example,

A change in a maintenance policy may lengthenProduction run times without damaging theequipment. This change reduces maintenancecost and, at the same time, increases productioncapacity.

Maintenance can usually make adjustments in tools,training, repair procedures, and work planning, all ofwhich can reduce the amount of labor or materials thatmay be required to perform a specific job.



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Provide accurate equipment maintenance records

Providing accurate equipment maintenance recordsenables a company to accurately track equipment in

such engineering terms as mean time between failureor mean time to repair. Success in this requiresaccurate records of each maintenance repair, theduration of the repair, and the run-time betweenrepairs.



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Collect necessary maintenance cost information

Collecting necessary maintenance-costinformation enables companies to trackengineering information. For example, by using

life-cycle costing information, companies canpurchase assets with the lowest life-cycle costsrather than lowest initial costs.Tracking all labor, material, contracting, and othermiscellaneous costs is primarily an activity for the

maintenance department.In addition to life cycle costing is the need formaintenance budgeting. If accurate cost historiesare not collected, how can the manager budgetwhat next year’s expenses will or should be?



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Optimize maintenance resources

By optimizing maintenance resources, organizationsimprove their effectiveness in eliminating maintenancewaste.

Optimizing maintenance resources can only be achievedby good planning and scheduling practices.



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Optimize capital equipment life

Optimizing the life of the capital equipment meansmaintaining it so that it lasts 30 to 40 percent longer thanpoorly-maintained equipment. The maintenancedepartment’s goal is to keep the equipment properlymaintained to achieve the longest life cycle.



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Minimize energy usageMinimizing energy usage is a natural result of well-maintainedequipment, which requires 5-to-11 percent less energy tooperate than poorly-maintained equipment.

Heat exchangers and coolers that are notcleaned at the proper frequency consume moreenergy.

Equipment with a poor maintenance schedule

will have bearings without proper lubrication oradjustment, couplings not properly aligned, orgears misaligned, all of which contribute topoor performance and require more energy tooperate.



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Minimize inventory on hand

Minimizing inventory on hand helps maintenanceorganizations eliminate waste. Approximately 50 percent of

a maintenance budget is spent on spare parts and materialconsumption. In organizations that are reactive, up to 20percent of spare parts cost may be waste. As organizationsbecome more planned and controlled, this waste iseliminated.


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Maintenance & Profitability


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Return on asset = Revenue / Asset value

Revenue = Price x Volume

Volume = Maximum Capacity x Overall Equipment

Effectiveness

More effective Maintenance works on both sides of the Return

on Asset equation. Improved maintenance helps to increase

revenues by increasing equipment performance. It also helps

to reduce the need for expensive capital upgrades to increase

output by keeping the assets in a good condition.



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An organization that still views

maintenance as a “cost center” and

continuously “squeezes blood from the

maintenance turnip” is on the road tomajor problems with physical asset

management.

This attitude has resulted in

catastrophic failures in airlines,

refineries, ships at sea, and many other

operations.



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Investments in maintenance that successfully implement the

best practices can achieve results that are comparable to :

• 15 to 25 percent increase in critical capacity constraining

equipment uptime

• 20 to 30 percent increase in maintenance productivity of the

craft workforce

• 25 to 30 percent increase in planned maintenance work

• 10 to 25 percent reduction in emergency repairs

• 20 to 30 percent reduction in excess and obsolete inventory

• 10 to 20 percent reduction in maintenance repair costs



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With a Net Profit Ratio of 5 Percent; the Potential forMaintenance toContribute to the Bottom Line Can be Significant



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Other improvements can include:

• Improved product quality

• Improved utilization of equipment operators

• Improved equipment productivity and production

throughput capacity

• Improved equipment life lower life cycle cost (LCC)

• Improved productivity of the total operation and pure

profit



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UnderstandingMaintenance Cost


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Proper maintenance of plant equipment can significantly

reduce the overall operating cost, while boosting the

productivity of the plant. Although many management

personnel often view plant maintenance as an expense,

a more positive approach in looking at it is to view

maintenance works as a profit center.

Understanding maintenance cost


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Maintenance costs are a major part of the total operating

costs of all manufacturing or production plants. Depending

on the specific industry, maintenance costs can representbetween 15 and 60 percent of the cost of goods produced.

For example, in food related industries, average

maintenance costs represent about 15 percent of the cost of

goods produced, whereas maintenance costs for iron and

steel, pulp and paper, and other heavy industries represent

up to 60 percent of the total production costs.

Facts & Figures



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The cost of maintaining equipment in a chemical processing

plant can range from 30% 50% of the plant’s total

operating budget. With such a large amount of capital being

placed in plant maintenance, it is imperative to establish an

economically optimal maintenance policy. The goals of any

policy are to maximize safety for both plant personnel and

the public, and to minimize the total cost to the plant by

decreasing loss of product and cost of maintenance.

Facts & Figures



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• According to DuPont, "maintenance is the largest single

controllable expenditure in a plant: in manycompanies it often exceeds annual net profit.”

• Downtime costs as much as $ 50,000 per hour.

• 30-40% of downtime is caused by poor design or

maintenance

Facts & Figures



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Maintenance costs, are normally a major portion of the total

operating costs in most plants. Traditional maintenance costs

(i.e., labor and material) in the United States have escalated

at a tremendous rate over the past years. In 1981, domestic

plants spent more than $600 billion to maintain their critical

plant systems. By 1991, the costs had increase to more than

$800 billion, by the year 2000 had reached to $1.2 trillion,

based on the same growth rate now a days it has reached

more than $1.6 trillion.

Facts & Figures



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Recent surveys of maintenance management effectiveness

indicate that on average, one third, or more than $500

billion, of all maintenance dollars are wasted through

ineffective maintenance management methods.

Facts & Figures



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Maintenance impact on the total operating expenses

Facts & Figures



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The costs of maintenance may be

divided into direct and indirect

costs. Direct maintenance costs

include staff, overtime pay,

benefits, outside contractors,

spare parts, and tools. Indirect

costs (which often dominate)

include high production costs, lost

production, reduced quality, and

poor customer service.

Direct maintenancecosts are often justthe tip of thepyramid.



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The direct costs are easy to justify and to report. The indirect

costs is hidden costs which are harder to measure. These

hidden cost of maintenance are classified as the six big losses:-

Breakdowns and unplanned plant shutdown losses

Excessive set-up, changeovers and adjustments losses

Idling and minor stoppages

Running at reduced speed

Startup losses and

Quality defects



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Cost of downtime is the cost of the equipment not running when

scheduled. This includes loss of sales, production labor hours (scheduled

production labor waiting for the repair to be made), special or express

shipment, unscheduled overtime and idle asset hours. Wait time includes

time for a work crew to respond to the failure, time to investigate the

failure and time to wait for parts and/or equipment necessary to make

the repair. Loss of sales and productive labor wait time are frequently the

highest costs associated with equipment failure. The actual cost willdepend on product demand and could range from several hundred dollars

per hour to tens of thousands of dollars per minute. The more frequent

and debilitating the failure, the more cost incurred.



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Cost of maintenance labor is the cost of fixing the equipment

(Labor Rate x Repair Personnel x Total Time to Fix). This

includes wait time (time for the work crew to wait for parts,

equipment, other members of the work crew, etc.), time tostage the repair, time to make the repair, verification time and

time to return the equipment to production status.

Cost of parts is the cost of the repair or replacement parts

required to return the system to service. It includes the basic

cost of the part, any delay due to unavailability, express

shipment, cost of inventory and cost of obsolescence (if any).



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Maintenance development over time


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Although humans have felt the need to

maintain their equipment since the

beginning of time, the beginning of modern

engineering maintenance may be regardedas the development of the steam engine by

James Watt in 1769 in Great Britain.

The maintenance jobs are done only when

it was no longer possible to run the

machine. That was called “Breakdown

Maintenance”.

Steam engine designed byWatt.


http://en.wikipedia.org/wiki/File:SteamEngine_Boulton&Watt_1784.jpg


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In the period of pre-World War II, people thought ofmaintenance as an added cost to the plant which did notincrease the value of finished product.

Therefore, the maintenance at that era was

restricted to fixing the unit when it breaks

because it was the cheapest alternative



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It was until 1950 that some groups of Japanese engineers

started a new concept in maintenance that consisted on

following the manufacturers’ recommendations about the care

that should be taken in the operation and maintenance of the

machines and devices. That new trend was called “Preventive

Maintenance”. As a result, plant managers were encouraged

to have their supervisors, mechanics, electricians and other

specialists, develop programs for lubricating and making key

observations to prevent damages of the equipment. Although

it helped reduce down-time, it was an expensive alternative.



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Nowadays, increased awareness of such issues as

environment safety, quality of product and services makesmaintenance one of the most important functions thatcontribute to the success of the industry.

World-class companies are in

continuous need of a very well organisedmaintenance programme to compete world-wide



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In general, the evolution of maintenance changes usually is

categorized into 3 different generation, the period of 1930’s-

1940’s which usually referred as the First Generation,

between 1950’s to 1970’s often recognized as the second

generation, and the 1980’s till recent which commonly

accepted as the third generation.



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The Evolution in the MaintenanceTechniques:

Third Generation:

Multi-skilling and teamwork

Condition monitoring

SecondGeneration:

Failure modes and effectsanalysis

Work planning andcontrol

Design for reliability andmaintainability

First

Generation:

Scheduled overhauls Specialized CMMS systems

Repair it when itbroke

Card systems andslow big computers

Small fast computers

← 1940 1950 1960 1970 1980 1990 2000 →



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The evolution in the maintenance process also rooted

from the changing complexity of the industry itself. The

first generation is the earlier days of industrialization

where mechanization is low. Most equipment in the

factory is basic and repairing and restoration process

is done in a very short time. Thus, the term downtime did

not matter much and there was no need for managers toput maintenance as a high priority issue.



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The second generation emerged as the results of growing complexity

in equipment and plant design. This had led to increase mechanization

and industry was beginning to depend on these complex machines.

Repairing and restoration has become more difficult and special skill and

more time is needed to mend the machinery. As this dependence grew,

downtime became more apparent a problem and getting a sharper focus

from the management. People are beginning to think that these failures

should be prevented which led to the concept of preventive

maintenance. As maintenance cost started to rise sharply relative to

other operating cost, there is a rising interest in the field of maintenance

planning and control systems.


i d l i


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Beginning in the 80’s, the growth of mechanization and

automation has becoming more complex and some small

breakdowns in equipment could effect the operation of the

whole plant. This has meant that reliability and availability havebecome a key issues since any failure can have a serious

consequences to the whole division.



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Fix it when it broke

Higher plant availability

Longer equipment life

Lower costs

Higher plant availability and reliability

Greater safety

Better product quality

No damage to the environment

Longer equipment life

Greater cost effectiveness

1940 1950 1960 1970 1980 1990 2000

Growing maintenance expectations



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Run to FailureMaintenance

Higher AvailabilityLonger Asset LifeLower CostsPreventive Maintenance

Reliability/Availability/Maintainability (RAM)Predictive Maintenance

Improved Product QualityGreater Cost EffectivenessSafety & Environment FocusLife Cycle Costs

1930 1950 1980 2000

The Right Maintenance at theRight Time using the RightPeople

Growing maintenance expectations



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Maintenance

Terms and Definitions


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• Downtime or outage duration refers to a periodof time that a system fails to provide orperform its primary function. This is usually aresult of the system failing to function because

of an unplanned event, or because of routinemaintenance.

• Time when a system is not producing product.Downtime includes scheduled and

unscheduled downtime.

• The opposite of downtime is uptime.

Maintenance Terms & Definitions

Downtime

M i t T & D fi iti

http://www.downtimecentral.com/index.php


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Failure

The termination of the ability of an item to fulfil its required

function(s).


A failure is either:• A POTENTIAL FAILURE, which is some physical

identifiable evidence that a functional failure isimminent.

or

• A FUNCTIONAL FAILURE, which is the inability of anitem (or the equipment containing it) to meet aspecified condition or performance standard.


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Failure Rate

At any point in the life of an item, the incremental change in

the number of failures per associated incremental change in

time.



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Failure Mode

• A failure mode is any “event” which causes a functional

failure

• A functional failure is the inability of any asset to fulfill a

function to a standard of performance which is acceptable to

the user

i.e. a functional failure is a “failed state”



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Function

Transfer of Water

Functional Failure

No water transferred

Functional Failure

Reduced water transfer rate

Failure Modes/Causes of Failure

1. Loose impeller

2. Jammed impeller

3. etc.

Failure Modes/Causes of Failure

1. Worn impeller

2. Blocked suction strainer

3. Etc.

Failure Modes

• A Failure Mode is any event which causes a functionalfailure




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Example: Consider a cooling water pumping system




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• Reliability is the probability that an item will survive a

given operating period, under specified operating

conditions, without failure

Or

• An item’s ability to perform its function under stated

conditions when required to do so.

Reliability




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Reliability is the probability that a plant or a machine or asingle item performs as it was intended when it wasdesigned.

Reliability is the probability that a piece of equipment, forexample is able to perform its defined function under statedconditions for a stated period of time or for a stated demand.

Institution of Chemical Engineers, 1985

Reliability

Reliability% = ((Period HRS - Unscheduled DownTime)/(Period HRS))*100


M i t T & D fi iti


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Reliability




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For Reliability calculation time can be expressed in twoways:

• Hours (operating and reference)

• Days (operating and reference)

Reliability




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Availability is the probability of being available (total time amachine is available) during one year - independent ofwhether the unit is needed or not.

Availability

Ability to perform when required




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Deals with the duration of up-time for operations and is ameasure of how often the system is alive and well. It is oftenexpressed as:

A = (uptime)/(uptime + downtime)Or

A = (Period Hrs - Down Time)/(Period Hrs)

Up-time refers to a capability to perform the task anddowntime refers to not being able to perform the task.As availability grows, the capacity for making moneyincreases because the equipment is in-service a larger percentof time.

Availability




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Suppose an operation is desired to operate around theclock (total time in one year is 8760 hours) and it has anavailability of 98%.

The process uptime is 0.98*8760 = 8584.8 HR/YR anddowntime of 0.02*8760 = 175.2 HRS/YR as (availability +unavailability) = 1. A system must be available (ready forservice) and reliability (absence of failures for thedesignated time interval) to produce effective results.

Availability is NOT the same as reliability. Availability tellshow time is used.

Availability




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MTBF (mean time between failure)

• Also known as Mean Time To Failure, Is a basic measure of

a system’s reliability. It is typically represented in units ofhours.

• The higher the MTBF number is, the higher the reliability ofthe product.

M TBF =Operating Tim e

Number of Failures or Breakdown Events




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MTBF

Maintenance effort required is increasing. Maintenance practices / mechanisms are ineffective. Failure frequency is increasing. Operating conditions are deteriorating.

Maintenance effort required is decreasing. Maintenance practices / mechanisms are effective. Failure frequency is decreasing. Operating conditions are improving.


M i T & D fi i i


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How to calculate?

Suppose a machine is scheduled to run nonstop for 480 minutes.

Instead, it runs 63 minutes, jams and goes down for 16 minutes, runs102 minutes, blows a fuse and is off line for 30 minutes, then runs

200 minutes before smoking a belt and going down for the rest of the

shift.

The MTBF would be calculated as:

63 Minutes + 102 Minutes + 200 Minutes ÷ 3 Occurrences =

121.7 Minutes MTBF.





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How to calculate?

― A pump, in a period of 10 years, had 15 maintenance

interventions due to failure. Its MTBF is:

MTBF =10 years

15 failures

120 months

15 failures 8months ==





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MTTR (mean time to repair) Is a basic measure of the maintainability of repairable

items. It represents the average time required to repair afailed component or device.

Expressed mathematically, it is the total correctivemaintenance time divided by the total number of correctivemaintenance actions during a given period of time.

Down time is the total time equipment (or plant) is downfor corrective maintenance. It generally does not include

lead time for parts not readily available or other

Administrative or Logistic Downtime (ALDT).

M TTR =Down Time

N um ber of Failures or Breakdow n Events




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MTTR (mean time to repair)

MTTR

Maintenance practices / mechanisms are effective. Clean-up (work preparation) practices effective. Effective work practices.

Maintenance practices / mechanisms are ineffective.

Poor clean-up (work preparation) practices. Ineffective work practices.




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MTTR (mean time to repair)

A machine that is scheduled to run nonstop for 480minutes and instead runs for 63 minutes, jams and goes

down for 16 minutes, runs 102 minutes, blows a fuse andis off line for 30 minutes, then runs 200 minutes beforesmoking a belt and going down for the rest of the shift (69minutes), MTTR would be calculated as 16 Minutes + 30Minutes + 69 Minutes + 21 Minutes (the additional time

after the shift it took to repair the problem)÷

3Occurrences = 45.3 Minutes MTTR.




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Availability / MTBF / MTTR

MTBF = mean time between failureMTTR = mean time to repair




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If MTBF = 11.5 months. If the MTTR is 3 days, MTTR = 0,1

month

an availability of 99.13%

Availability / MTBF / MTTR




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Maintainability is the ability to retain or restore functionwithin a specified period of time, when provided with an

identified level of tools, training, and procedures.Maintainability factors include:• Access - Equipment, its components, and facilities

should be accessible for maintenance

Maintainability




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Maintainability characteristics are usually determined byequipment design, which then sets maintenanceprocedures and determine the length of repair times.

A key maintainability figure of merit is the mean time torepair (MTTR) and a limit for the maximum repair time.

Maintainability




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Availability / Reliability / Maintainability




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Redundancy refers to the ability to perform the same defined

operational function by a number of independent but identical

means.

Institution of Chemical Engineers, 1985


Redundancy



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Having more than one item that has the same function in

the case of one failing. These multiple pieces of equipment

are used to help improve the reliability and availability ofthe system. Redundancy is generally expressed as the

number of pieces of equipment required and the total

number available. For example, 2 out of 3 means that

there are a total of 3 pieces of equipment and 2 pieces are

required for proper operation of the system.


Redundancy

Network Reliability Systems


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Series Network

• In processes using series networks, no failure of any

component can be accepted because there is no redundancy

built into the system

• If one of the individual components fails then the overall

system fails

• If, for example, the reliabilities of three components (A,B,C)

are RA, RB and RC respectively then the overall system reliability

is given by:

• RS = RA x RB x RC

CA B



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Parallel Network

• In order to ensure that a system will continue to operate

if at least one of its individual components operates, the

components must be placed in parallel:

• If, for example, the reliabilities of three components

(A,B,C) are RA, RB and RC respectively then the overall

system reliability is given by:

RS = 1 – [(1 – RA) x (1 – RB) x (1 – RC)] B

A

C



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et o e ab ty Syste s

Mixed Series and Parallel Network

• A system may be made up of a mixture of series and

parallel components:

• If, for example, the reliabilities of four components

(A,B,C,D) are RA, RB, RC and RD respectively then:

RS(A,B) = RA x RB

RS(C,D) = RC x RD

• And the overall system reliability is:

RS = 1 – [(1 – RS(A,B)) x (1 – RS(C,D))]D

BA

C



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Reliability networks can be more complex than just seriesand parallel networks, which requires more complexmathematics to quantify.

The reliability of an overall system increases as the level ofredundancy is increased, but.

The return on investment decreases as the level ofredundancy.

However increased redundancy may be required for reasonsrelating to:

• Safety• Environment

• Consequential costs (lost production, etc.) of systemfailures


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Maintenance Policies



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Classification of maintenance policies

Failure-BasedCorrective(Reactive):

Time-BasedPreventive

(PM):- Calendar:

WeeklyMonthlyAnnually

- Running:1000 K.M.

Condition-BasedPredictive (PdM):- Oil analysis- Vibration analysis- Temperatureanalysis- Wear analysis

- Efficiency analysis

Reliability-BasedProactive (PaM):- RCFA

- FMEA- RCM- RBI- LCC


Maintenance Policies - Comparisons


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Type of maintenance strategy

Maintenance Policies Comparisons

Day 1- Part 1- Understanding Maintenance (Short) - Updated 10-10-2014.pdf

Documents

Transcript of Day 1- Part 1- Understanding Maintenance (Short) - Updated 10-10-2014.pdf