Maintenance utility and engineering in process engineering

How maintenance is essential for optimum working of machinery

1. HISTORY,
OBJECTIVES AND
TYPES OF
MAINTENANCE

2. MAINTENANCE
DEFINITION
According to British Standard Glossary of terms
maintenance can be defined as:
the combination of all technical and administrative
actions, including supervision actions, intended to
retain an item in, or restore it to, a state in which it
can perform a required function.

3. MAINTENANCE
DEFINITION
maintenanceisasetoforganisedactivitiesthat
arecarriedoutinordertokeepaniteminitsbest
operationalconditionwithminimumcost
acquired.

4. MAINTENANCE HISTORY
1.In the period of pre-World War II, people thought of
maintenance as an added cost to the plant which did
not increase 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

5. MAINTENANCE HISTORY
2.DuringandafterWorldWarIIatthetimewhenthe
advancesofengineeringandscientifictechnology
developed,peopledevelopedothertypesof
maintenance,whichweremuchcheapersuchas
preventivemaintenance.
Inaddition,peopleinthiseraclassified
maintenanceasafunctionoftheproductionsystem.

6. MAINTENANCE HISTORY
Fix the
equipment
when it
breaks
Models for
preventive
maintenance
developed.
-Increased
awareness of:
-Environment
-Safety
-Quality
-Need for reliable
equipment.
-Reduction in
costs.
Pre-World War II Post-World War II 1980 Onwards
Time
Development of
Maintenance
Figure 2.2 Maintenance History
(Adapted From Shenoy, Bhadury 1998)

7. MAINTENANCE HISTORY
3.Nowadays,increasedawarenessofsuchissuesas
environmentsafety,qualityofproductandservices
makesmaintenanceoneofthemostimportant
functionsthatcontributetothesuccessofthe
industry.
World-classcompaniesarein
continuousneedofaverywellorganised
maintenanceprogrammetocompeteworld-wide.

8. MAINTENANCE
ACTIVITIES
Activitiesofmaintenancefunctioncouldbeeither
repairorreplacementactivities,whicharenecessary
foranitemtoreachitsacceptableproductivity
conditionandtheseactivities,shouldbecarriedout
withaminimumpossiblecost.

9. MAINTENANCE
OBJECTIVES
Maintenanceobjectivesshouldbeconsistentwithand
subordinatetoproductiongoals.
Therelationbetweenmaintenanceobjectivesand
productiongoalsisreflectedintheactionofkeeping
productionmachinesandfacilitiesinthebestpossible
condition.

10. MAINTENANCE
OBJECTIVES
•Maximisingproductionorincreasingfacilities
availabilityatthelowestcostandatthehighest
qualityandsafetystandards.
•Reducingbreakdownsandemergencyshutdowns.
•Optimisingresourcesutilisation.
•Reducingdowntime.
•Improvingsparesstockcontrol.

11. MAINTENANCE
OBJECTIVES
•Improvingequipmentefficiencyandreducingscrap
rate.
•Minimisingenergyusage.
•Optimisingtheusefullifeofequipment.
•Providingreliablecostandbudgetarycontrol.
•Identifyingandimplementingcostreductions.

12. MAINTENANCE
OBJECTIVES
PLANT
M
A
I
N
T
E
N
A
N
C
E
Reduce Breakdowns
Reduce Downtime
Improving Equipment
Efficiency
Improving Inventory
Control
Implementing Cost
Reduction
Maximising Production
Optimising Resources
Utilisation
Optimising Useful Life
of Equipment
Minimising Energy
Usage
Providing Budgetary
Control
Figure 2.3 Maintenance Objectives

13. •A measure of the amount of maintenance downtime required to keep
equipment (or plant) operating.
Formula
–Operating time is productive time plus production delays.
–Down timeis the total time equipment (or plant) is down for maintenance work (preventive and
corrective).
InterpretationMaintenance Effectiveness=
Operating Time
Operating Time+Down Time
x 100%





 Maintenance Effectiveness > 95%
•Maintenance effort required is increasing.
•Maintenance practices / mechanisms are ineffective.
•Operating conditions are deteriorating.
•Equipment is being over maintained.
•Maintenance effort required is decreasing.
•Maintenance practices / mechanisms are effective.
•Operating conditions are improving.
Maintenance Effectiveness

14. •A measure of the maintenance effort required to deliver required
performance levels from equipment (or plant).
Formula
–Maintenance man hours is the actual maintenance man hours spent maintaining an item of
equipment (or plant). Maintenance man hours includes maintenance wages, staff and contractor
hours (preventive and corrective).
–Operating time is productive time plus production delays.
InterpretationMaintenance Efficiency=
Maintenance Man Hours
Operating Time
x 100%





 Maintenance Efficiency
•Maintenance effort required is increasing.
•Maintenance practices / mechanisms are ineffective.
•Operating conditions are deteriorating.
•Equipment is being over maintained.
•Maintenance effort required is decreasing.
•Maintenance practices / mechanisms are effective.
•Operating conditions are improving.
Maintenance Efficiency

15. TYPES OF MAINTENANCE
MAINTENANCE
UNPLANNED
MAINTENANCE
(REACTIVE)
BREAKDOWNEMERGENCY
PLANNED
MAINTENANCE
(PROACTIVE)
CORRECTIVE
MAINTENANCE
REMEDIALDEFERRED
PREDECTIVE
MAINTENANCE
CONDITION -
BASED
STATISTICAL -
BASED
PREVENTIVE
MAINTENANCE
ROUTINE RUNNING
DESIGN -OUTENGINEERING
SERVICES
WINDOW
IMPROVEMENT
MAINTENANCE
SHUTDOWN
CORRECTIVE
SHUTDOWN
PREVENTIVE
SHUTDOWN
IMPROVEMENT
Shutdown Maintenance
OPPORTU-
NITY
Figure 2.4 Maintenance Types

16. TYPES OF MAINTENANCE
•RuntoFailureMaintenance(RTF)
•PreventiveMaintenance(PM)
•CorrectiveMaintenance(CM)
•ImprovementMaintenance(IM)
•PredictiveMaintenance(PDM)

17. RUN TO FAILURE MAINTENANCE
(RTF)
•Therequiredrepair,replacement,orrestoreaction
performedonamachineorafacilityafterthe
occurrenceofafailureinordertobringthis
machineorfacilitytoatleastitsminimum
acceptablecondition.
•Itistheoldesttypeofmaintenance.

18. RUN TO FAILURE MAINTENANCE
(RTF)

19. RUN TO FAILURE
MAINTENANCE (RTF)
•Itissubdividedintotwotypes:
•Emergencymaintenance:itiscarriedoutasfastaspossiblein
ordertobringafailedmachineorfacilitytoasafeand
operationallyefficientcondition.
•Breakdownmaintenance:itisperformedaftertheoccurrenceof
anadvancedconsideredfailureforwhichadvancedprovisionhas
beenmadeintheformofrepairmethod,spares,materials,labour
andequipment.

20. RUN TO FAILURE
MAINTENANCE (RTF)
•Advantages:
1.Minimalplanning–Sincemaintenancedoesnotneedtobe
scheduledinadvance,theplanningrequirementsarevery
low.Maintenanceonlyneedstohappenafterbreakdown
hasoccurred.
2.Easytounderstand–Becauseoftheplan’ssimplicity,this
systemiseasytounderstandandimplement.

21. RUN TO FAILURE
MAINTENANCE (RTF)
•Disadvantages:
1.Itsactivitiesareexpensiveintermsofbothdirectandindirect
cost.
2.Usingthistypeofmaintenance,theoccurrenceofafailureina
componentcancausefailuresinothercomponentsinthesame
equipment,whichleadstolowproductionavailability.
3.Itsactivitiesareverydifficulttoplanandscheduleinadvance.

22. RUN TO FAILURE
MAINTENANCE (RTF)
•Thistypeofmaintenanceisusefulinthefollowingsituations:
1.Thefailureofacomponentinasystemisunpredictable.
2.Thecostofperformingruntofailuremaintenanceactivitiesis
lowerthanperformingotheractivitiesofothertypesof
maintenance.
3.Theequipmentfailurepriorityistoolowinordertoincludethe
activitiesofpreventingitwithintheplannedmaintenance
budget.

23. PREVENTIVE
MAINTENANCE (PM)
Itisasetofactivitiesthatareperformedonplant
equipment,machinery,andsystemsbeforethe
occurrenceofafailureinordertoprotectthem
andtopreventoreliminateanydegradationin
theiroperatingconditions.

24. PREVENTIVE
MAINTENANCE (PM)
BritishStandard3811:1993Glossaryofterms
definedpreventivemaintenanceas:
themaintenancecarriedoutatpredetermined
intervalsoraccordingtoprescribedcriteriaand
intendedtoreducetheprobabilityoffailureorthe
degradationofthefunctioningandtheeffects
limited.

25. PREVENTIVE
MAINTENANCE (PM)
•Theadvantageofapplyingpreventive
maintenanceactivitiesistosatisfymostof
maintenanceobjectives.

26. PREVENTIVE
MAINTENANCE (PM)
•Thefactorsthataffecttheefficiencyofthistypeofmaintenance:
1.Theneedforanadequatenumberofstaffinthemaintenance
departmentinordertoperformthistypeofmaintenance.
2.Therightchoiceofproductionequipmentandmachinerythatis
suitablefortheworkingenvironmentandthatcantoleratethe
workloadofthisenvironment.
3.Therequiredstaffqualificationsandskills,whichcanbegained
throughtraining.
4.ThesupportandcommitmentfromexecutivemanagementtothePM
programme.
5.TheproperplanningandschedulingofPMprogramme.
6.TheabilitytoproperlyapplythePMprogramme.

27. PREVENTIVE
MAINTENANCE (PM)
•Itisgoodforthosemachinesandfacilitieswhich
theirfailurewouldcauseseriousproduction
losses.
•Itsaimistomaintainmachinesandfacilitiesin
suchaconditionthatbreakdownsandemergency
repairsareminimised.
•Itsactivitiesincludereplacements,adjustments,
majoroverhauls,inspectionsandlubrications.

28. PREVENTIVE
MAINTENANCE (PM)
•Researcherssubdividedpreventivemaintenanceinto
differentkindsaccordingtothenatureofitsactivities:
•Routinemaintenancewhichincludesthosemaintenance
activitiesthatarerepetitiveandperiodicinnaturesuchas
lubrication,cleaning,andsmalladjustment.
•Runningmaintenancewhichincludesthosemaintenance
activitiesthatarecarriedoutwhilethemachineor
equipmentisrunningandtheyrepresentthoseactivities
thatareperformedbeforetheactualpreventive
maintenanceactivitiestakeplace.

29. PREVENTIVE
MAINTENANCE (PM)
•Opportunitymaintenancewhichisasetofmaintenance
activitiesthatareperformedonamachineorafacility
whenanunplannedopportunityexistsduringtheperiodof
performingplannedmaintenanceactivitiestoother
machinesorfacilities.
•Windowmaintenancewhichisasetofactivitiesthatare
carriedoutwhenamachineorequipmentisnotrequired
foradefiniteperiodoftime.
•Shutdownpreventivemaintenance,whichisasetof
preventivemaintenanceactivitiesthatarecarriedout
whentheproductionlineisintotalstoppagesituation.

30. CORRECTIVE
MAINTENANCE (CM)
•Inthistype,actionssuchasrepair,replacement,
orrestorewillbecarriedoutaftertheoccurrence
ofafailureinordertoeliminatethesourceofthis
failureorreducethefrequencyofitsoccurrence.
AccordingtoBritishStandardGlossaryofterms,
correctivemaintenanceisdefinedas:
themaintenancecarriedoutafterrecognitionandintended
toputanitemintoastateinwhichitcanperforma
requiredfunction.

31. CORRECTIVE
MAINTENANCE (CM)
•Thistypeofmaintenanceissubdividedintothree
types:
•Remedialmaintenance,whichisasetofactivities
thatareperformedtoeliminatethesourceof
failurewithoutinterruptingthecontinuityofthe
productionprocess.
Thewaytocarryoutthistypeofcorrectivemaintenance
isbytakingtheitemtobecorrectedoutoftheproduction
lineandreplacingitwithreconditioneditemor
transferringitsworkloadtoitsredundancy.

32. CORRECTIVE
MAINTENANCE (CM)
•Deferredmaintenance,whichisasetof
correctivemaintenanceactivitiesthatarenot
immediatelyinitiatedaftertheoccurrenceofa
failurebutaredelayedinsuchawaythatwillnot
affecttheproductionprocess.
•Shutdowncorrectivemaintenance,whichisaset
ofcorrectivemaintenanceactivitiesthatare
performedwhentheproductionlineisintotal
stoppagesituation.

33. CORRECTIVE
MAINTENANCE (CM)
•Themainobjectivesofcorrectivemaintenancearethe
maximisationoftheeffectivenessofallcriticalplantsystems,
theeliminationofbreakdowns,theeliminationofunnecessary
repair,andthereductionofthedeviationsfromoptimum
operatingconditions.
•Thedifferencebetweencorrectivemaintenanceandpreventive
maintenanceisthatforthecorrectivemaintenance,thefailure
shouldoccurbeforeanycorrectiveactionistaken.
•Correctivemaintenanceisdifferentfromruntofailure
maintenanceinthatitsactivitiesareplannedandregularly
takenouttokeepplant’smachinesandequipmentinoptimum
operatingcondition.

34. CORRECTIVE
MAINTENANCE (CM)
•Thewaytoperformcorrectivemaintenanceactivitiesisby
conductingfourimportantsteps:
1.Faultdetection.
2.Faultisolation.
3.Faultelimination.
4.Verificationoffaultelimination.
Inthefaulteliminationstepseveralactionscouldbetakensuch
asadjusting,aligning,calibrating,reworking,removing,
replacingorrenovation.

35. CORRECTIVE
MAINTENANCE (CM)
•Correctivemaintenancehasseveralprerequisites
inordertobecarriedouteffectively:
1.Accurateidentificationofincipientproblems.
2.Effectiveplanningwhichdependsontheskillsofthe
planners,theavailabilityofwelldevelopedmaintenance
databaseaboutstandardtimetorepair,acompleterepair
procedures,andtherequiredlabourskills,specifictools,
partsandequipment.
3.Properrepairprocedures.
4.Adequatetimetorepair.
5.Verificationofrepair.

36. IMPROVEMENT
MAINTENANCE (IM)
•Itaimsatreducingoreliminatingentirelytheneedfor
maintenance.
•Thistypeofmaintenanceissubdividedintothreetypesas
follows:
1.Design-outmaintenancewhichisasetofactivitiesthat
areusedtoeliminatethecauseofmaintenance,simplify
maintenancetasks,orraisemachineperformancefromthe
maintenancepointofviewbyredesigningthosemachines
andfacilitieswhicharevulnerabletofrequentoccurrence
offailureandtheirlongtermrepairorreplacementcostis
veryexpensive.

37. IMPROVEMENT
MAINTENANCE (IM)
2.Engineeringserviceswhichincludesconstructionand
constructionmodification,removalandinstallation,and
rearrangementoffacilities.
3.Shutdownimprovementmaintenance,whichisasetof
improvementmaintenanceactivitiesthatareperformed
whiletheproductionlineisinacompletestoppage
situation.

38. PREDICTIVE
MAINTENANCE (PDM)
•Predictivemaintenanceisasetofactivitiesthatdetect
changesinthephysicalconditionofequipment(signsof
failure)inordertocarryouttheappropriatemaintenance
workformaximisingtheservicelifeofequipmentwithout
increasingtheriskoffailure.
•Itisclassifiedintotwokindsaccordingtothemethodsof
detectingthesignsoffailure:
•Condition-basedpredictivemaintenance
•Statistical-basedpredictivemaintenance

39. PREDICTIVE
MAINTENANCE (PDM)
•Condition-basedpredictivemaintenancedependson
continuousorperiodicconditionmonitoringequipmentto
detectthesignsoffailure.
•Statistical-basedpredictivemaintenancedependson
statisticaldatafromthemeticulousrecordingofthe
stoppagesofthein-plantitemsandcomponentsinorderto
developmodelsforpredictingfailures.

40. PREDICTIVE
MAINTENANCE (PDM)
•Thedrawbackofpredictivemaintenanceisthatitdepends
heavilyoninformationandthecorrectinterpretationofthe
information.
•Someresearchersclassifiedpredictivemaintenanceasatypeof
preventivemaintenance.
•Themaindifferencebetweenpreventivemaintenanceand
predictivemaintenanceisthatpredictivemaintenanceuses
monitoringtheconditionofmachinesorequipmentto
determinetheactualmeantimetofailurewhereaspreventive
maintenancedependsonindustrialaveragelifestatistics.

41. ANY QUESTION