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RELIABILITY-CENTERED MAINTENANCE (RCM) :RELIABILITY-
CENTERED MAINTENANCE (RCM) RCM IS A SYSTEMATIC CONSIDERATION
OF SYSTEM FUNCTIONS, THE WAY FUNCTIONS CAN FAIL, & A PRIORITY-BASED CONSIDERATION OF SAFETY AND ECONOMICS THAT IDENTIFIES
APPLICABLE & EFFECTIVE PM TASKS.
RELIABILITY-CENTERED MAINTENANCE (RCM) :RELIABILITY-
CENTERED MAINTENANCE (RCM) RELIABILITY-CENTERED MAINTENANCE(RCM) IS THE PROCESS OF DETERMINING THE MOST EFFECTIVE
MAINTENANCEAPPROACH. RCM WAS FIRST APPLIED ON A LARGE SCALE
TO DEVELOP THE MAINTENANCE PROGRAM OF THE BOEING 747. KNOWN
AS MSG-3 IN THE AEROSPACE INDUSTRY.
RELIABILITY-CENTERED MAINTENANCE (RCM): RELIABILITY-
CENTERED MAINTENANCE (RCM) RCM IS A TECHNIQUE FOR DEVELOPINGA PM PROGRAM. IT IS BASED ON THE ASSUMPTION THAT THE INHERENT
RELIABILITY OF THE EQUIPMENT IS A FUNCTION OF THE DESIGN AND THEBUILD IN QUALITY. AN EFFECTIVE PM PROGRAM WILL ENSURE THAT THE
INHERENT RELIABILITY IS REALISED.
MAIN OBJECTIVE OF RCM: MAIN OBJECTIVE OF RCM TO REDUCE THE
MAINTENANCE COST, BY FOCUSING ON THE MOST IMPORTANT
FUNCTIONS OF THE SYSTEMS, AND AVOIDING OR REMOVINGMAINTENANCE ACTIONS THAT ARE NOT STRICTLY NECESSARY.
RCM HISTORY :RCM HISTORY ORIGINATED IN THE AIRLINE INDUSTRY IN
THE 1960S. BY THE LATE 1950S, THECOST OF MAINTENANCE ACTIVITIES
IN THE AIRLINE INDUSTRY HAD BECOME HIGH ENOUGH TO WARRANT ASPECIALINVESTIGATION INTO THE EFFECTIVENESS OF THOSE ACTIVITIES.
ACCORDINGLY, IN 1960, A TASK FORCE WAS FORMED.
RELIABILITY CENTERED MAINTENANCE HISTORY :RELIABILITY
CENTERED MAINTENANCE HISTORY CONSISTING OF REPRESENTATIVES
OF BOTH THE AIRLINES AND THE FEDERAL AVAITION ADMINISTRATION(FAA-US) TO INVESTIGATE THE CAPABILITIES OFPREVENTIVE
MAINTENANCE. THE ESTABLISHMENT OF THIS TASK FORCE
SUBSEQUENTLY LED TO THE DEVELOPMENT OF A SERIES OF GUIDELINESFOR AIRLINES AND AIRCRAFT MANUFACTURERS TO USE, WHEN
ESTABLISHING MAINTENANCESCHEDULES FOR THEIR AIRCRAFT.
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RCM PHILOSOPHY EMPLOYS THESE TECHNIQUES :RCM PHILOSOPHY
EMPLOYS THESE TECHNIQUES PREVENTIVE MAINTENANCE (PM)
PREDICTIVE MAINTENANCE (PDM) REAL-TIME MONITORING (RTM1) RUN-TO-FAILURE (RTF - ALSO CALLED REACTIVE MAINTENANCE) PROACTIVE
MAINTENANCE
THE GOAL OF THE RCM PHILOSOPHY :THE GOAL OF THE RCM
PHILOSOPHY TO PROVIDE THE STATED FUNCTION OF THE FACILITY, WITHTHE REQUIRED RELIABILITY ANDAVAILABILITY AT THE LOWEST COST.
RCM REQUIRES THAT MAINTENANCE DECISIONS BE BASED ON
MAINTENANCEREQUIREMENTS SUPPORTED BY SOUND TECHNICAL AND
ECONOMIC JUSTIFICATION.
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM IS
FUNCTION ORIENTED IT SEEKS TO PRESERVE SYSTEM OR EQUIPMENTFUNCTION, NOT JUSTOPERABILITY FOR OPERABILITY'S SAKE.
REDUNDANCY OF FUNCTION, THROUGH MULTIPLE EQUIPMENT,IMPROVESFUNCTIONAL RELIABILITY, BUT INCREASES LIFE CYCLE COST IN TERMS
OF PROCUREMENT ANDOPERATING COSTS.
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM IS SYSTEM
FOCUSED IT IS MORE CONCERNED WITH MAINTAINING SYSTEM FUNCTION
THANINDIVIDUAL COMPONENT FUNCTION. RCM IS DRIVEN BY SAFETYAND ECONOMICS SAFETY MUST BE ENSURED AT ANY COST; THEREAFTER,
COST-EFFECTIVENESS BECOMES THE CRITERION.
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM IS
RELIABILITY CENTERED IT TREATS FAILURE STATISTICS IN ANACTUARIAL MANNER. THE RELATIONSHIP BETWEEN OPERATING AGE AND
THE FAILURES EXPERIENCED IS IMPORTANT. RCM IS NOT OVERLY
CONCERNED WITH SIMPLE FAILURE RATE IT SEEKS TO KNOW THE
CONDITIONAL PROBABILITY OF FAILURE AT SPECIFIC AGES (THEPROBABILITY THAT FAILURE WILL OCCUR IN EACH GIVEN OPERATING
AGE BRACKET).
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM
ACKNOWLEDGES DESIGN LIMITATIONS ITS OBJECTIVE IS TO MAINTAINTHE INHERENT RELIABILITY OF THE EQUIPMENT DESIGN, RECOGNIZING
THAT CHANGES IN INHERENT RELIABILITY ARE THE PROVINCE OF DESIGN
RATHER THAN MAINTENANCE. RCM RECOGNIZES THAT MAINTENANCE
FEEDBACK CAN IMPROVE ON THE ORIGINAL DESIGN. RCM RECOGNIZES
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THAT A DIFFERENCE OFTEN EXISTS BETWEEN THE PERCEIVED DESIGN
LIFE AND THE INTRINSIC OR ACTUAL DESIGN LIFE, AND ADDRESSES THIS
THROUGH THE AGE EXPLORATION (AE) PROCESS.
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM DEFINESFAILURE AS ANY UNSATISFACTORY CONDITION THEREFORE, FAILURE
MAY BE EITHER A LOSS OF FUNCTION (OPERATION CEASES) OR A LOSS OF
ACCEPTABLE QUALITY (OPERATION CONTINUES).
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM USES A
LOGIC TREE TO SCREEN MAINTENANCE TASKS THIS PROVIDES ACONSISTENT APPROACH TO THE MAINTENANCE OF ALL KINDS OF
EQUIPMENT.
RCM LOGIC TREE :RCM LOGIC TREE
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM TASKS
MUST BE APPLICABLE THE TASKS MUST ADDRESS THE FAILURE MODEAND CONSIDER THE FAILURE MODE CHARACTERISTICS. RCM TASKS MUST
BE EFFECTIVE THE TASKS MUST REDUCE THE PROBABILITY OF FAILURE
AND BE COST EFFECTIVE.
THREE TYPES OF MAINTENANCE TASKS :THREE TYPES OF
MAINTENANCE TASKS TIME-DIRECTED (PM) SCHEDULED WHENAPPROPRIATE. CONDITION-DIRECTED (PDM AND REAL-TIME MONITORING)
PERFORMED WHEN CONDITIONS INDICATE THEY ARE NEEDED. FAILURE
FINDING (ONE OF SEVERAL ASPECTS OF PROACTIVE MAINTENANCE)AFTER IT HAS FAILED, INVESTIGATE THE CAUSES OF FAILURES.
EQUIPMENT IS RUN-TO-FAILURE. THIS IS ACCEPTABLE FOR SOME
SITUATIONS AND SOME TYPES OF EQUIPMENT.
PRIMARY RCM PRINCIPLES :PRIMARY RCM PRINCIPLES RCM IS A LIVING
SYSTEM IT GATHERS DATA FROM THE RESULTS ACHIEVED AND FEEDSTHIS DATA BACK TO IMPROVE DESIGN AND FUTURE MAINTENANCE. THIS
FEEDBACK IS AN IMPORTANT PART OF THE PROACTIVE MAINTENANCE
ELEMENT OF THE RCM PROGRAM.
RCM ANALYSIS CONSIDERS THE FOLLOWING QUESTIONS :RCM
ANALYSIS CONSIDERS THE FOLLOWING QUESTIONS WHAT DOES THE
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SYSTEM OR EQUIPMENT DO? WHAT IS ITS FUNCTION? WHAT FUNCTIONAL
FAILURES ARE LIKELY TO OCCUR? WHAT ARE THE LIKELY
CONSEQUENCES OF THESE FUNCTIONAL FAILURES? WHAT CAN BE DONETO REDUCE THE PROBABILITY OF THE FAILURE? IDENTIFY THE ONSET OF
FAILURE, OR REDUCE THE CONSEQUENCES OF THE FAILURE?
RCM IS APPLICABLE TO :RCM IS APPLICABLE TO WHERE LARGE,
COMPLEX EQUIPMENT IS USED WHERE EQUIPMENT FAILURES POSESIGNIFICANT ECONOMIC, SAFETY, OR ENVIRONMENTAL RISKS. AERO /
ASTRO INDUSTRIES NAVY UTILITY COMPANIES OFFSHORE INDUSTRY
MANUFACTURING PROCESS
BENEFITS OF RCM :BENEFITS OF RCM
INSTITUTING AN RCM PROGRAM DEPEND ON :INSTITUTING AN RCM
PROGRAM DEPEND ON NATURE OF THE BUSINESS RISKS POSED BYEQUIPMENT FAILURE STATE OF THE EXISTING MAINTENANCE PROGRAM
TO DEVELOP AN RCM PROGRAM :TO DEVELOP AN RCM PROGRAM WHAT
ASSETS ARE OWNED & OPERATED BY THE COMPANY? TO WHICH OF THESE
SHOULD RCM BE APPLIED? WHAT ARE THE FUNCTIONS & PERFORMANCE
EXPECTATIONS OF EACH SELECTED ASSET? IN WHAT WAYS CAN IT FAILTO PERFORM THESE FUNCTIONS?
TO DEVELOP AN RCM PROGRAM :TO DEVELOP AN RCM PROGRAM WHAT
CAUSES IT TO FAIL? WHAT ARE THE CONSEQUENCES OF EACH FAILURE?
WHAT SHOULD BE DONE TO PREVENT EACH FAILURE? WHAT STEPSSHOULD BE TAKEN IF PREVENTIVE MEASURES CANT BE FOUND?
PURPOSE OF THE RCM REVIEW PROCESS :PURPOSE OF THE RCM REVIEWPROCESS TO DEFINE THE MAINTENANCE REQUIREMENTS FOR A PHYSICAL
ASSET THAT ARE NECESSARY TO MEET THE BUSINESS OBJECTIVES. THE
LEVEL OF PERFORMANCE REFLECTS WHAT IS REQUIRED OR WANTEDFROM THE ASSET.
MAJOR STEPS IN THE RCM REVIEW PROCESS :MAJOR STEPS IN THE RCM
REVIEW PROCESS STEP 1 SELECT PLANT AREAS THAT MATTER STEP 2
DETERMINE KEY FUNCTIONS & PRODUCTIVITY GOALS STEP 3 DETERMINE
PLAUSIBLE FUNCTIONAL FAILURES STEP 4 DETERMINE LIKELY FAILURE
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MODES & THEIR EFFECTS
MAJOR STEPS IN THE RCM REVIEW PROCESS :MAJOR STEPS IN THE RCM
REVIEW PROCESS STEP 5 SELECT FEASIBLE & EFFECTIVE MAINTENANCE
TACTICS STEP 6 IMPLEMENT SELECTED TACTICS STEP 7 OPTIMIZE TACTICS& PROGRAMS
STEP 1 - SELECT PLANT AREAS THAT MATTER :STEP 1 - SELECT PLANT
AREAS THAT MATTER ESTABLISH A STRUCTURED, COMPREHENSIVE LIST
OF ALL PHYSICAL ASSETS OWNED OR USED THAT REQUIRE SOME FORM
OF MAINTENANCE OR ENGINEERING ATTENTION. PLANT REGISTER, PLANTINVENTORY, OR EQUIPMENT FAMILY TREE IDENTIFY & PRIORITIZE THE
PHYSICAL RESOURCES.
STEP 1 - SELECT PLANT AREAS THAT MATTER :STEP 1 - SELECT PLANT
AREAS THAT MATTER ASSESS THE IMPACT OF THE PHYSICAL RESOURCESON THE KEY BUSINESS PERFORMANCE AREA. AVAILABILITY PROCESS
CAPABILITY QUALITY COSTS SAFETY/ENVIRONMENTAL RISKS
STEP 1 - SELECT PLANT AREAS THAT MATTER :STEP 1 - SELECT PLANT
AREAS THAT MATTER ESTABLISH THE BOUNDARIES BETWEEN
EQUIPMENT SYSTEMS. DEFINES THE SCOPE OF THE REVIEW & ORGANIZESIT INTO MANAGEABLE PIECES.
STEP 2 DETERMINE KEY FUNCTIONS & PRODUCTIVITY GOALS :STEP 2
DETERMINE KEY FUNCTIONS & PRODUCTIVITY GOALS THE PURPOSE OF
THE MAINTENANCE TACTIC IS TO MAKE SURE THE EQUIPMENT ISWORKING PROPERLY & PRODUCING ON SCHEDULE.
STEP 2 DETERMINE KEY FUNCTIONS & PRODUCTIVITY GOALS :STEP 2 DETERMINE KEY FUNCTIONS & PRODUCTIVITY GOALS CATEGORIES OF
PHYSICAL ASSETS IN TERMS OF FUNCTION PRIMARY WHY THE
EQUIPMENT EXISTS AT ALL. SECONDARY LESS OBVIOUS PRIMARYFUNCTION BUT THE CONSEQUENCES OF FAILURE MAY BE NO LESS
SEVERE. PROTECTIVE
STEP 2 DETERMINE KEY FUNCTIONS & PRODUCTIVITY GOALS :STEP 2
DETERMINE KEY FUNCTIONS & PRODUCTIVITY GOALS MAINTENANCE
PERFORMANCE MAY BE DEFINED IN TERMS OF BUILT-IN WHAT IT CAN
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DO REQUIRED WHAT WE WANT IT TO DO ACTUAL WHAT IT IS DOING
STEP 3 DETERMINE PLAUSIBLE FUNCTIONAL FAILURES :STEP 3
DETERMINE PLAUSIBLE FUNCTIONAL FAILURES FUNCTIONAL FAILURES
TOTAL LOSS OF FUNCTION PARTIAL LOSS OF FUNCTION MULTIPLE LEVELSOF PERFORMANCE EXPECTED FROM AN INDIVIDUAL FUNCTION.
STEP 4 DETERMINE LIKELY FAILURE MODES AND THEIR EFFECTS
:STEP 4 DETERMINE LIKELY FAILURE MODES AND THEIR EFFECTS
LIKELY FAILURE MODES THOSE THAT OCCURRED ON THE SAME OR
SIMILAR EQUIPMENT. THOSE ALREADY THE SUBJECT OF PREVENTIVEMAINTENANCE TASKS. THOSE THAT HAVE NOT HAPPENED BUT ARE
CONSIDERED POSSIBLE BECAUSE OF EXPERIENCE OR
VENDOR/MANUFACTURER RECOMMENDATIONS.
STEP 4 DETERMINE LIKELY FAILURE MODES AND THEIR EFFECTS
:STEP 4 DETERMINE LIKELY FAILURE MODES AND THEIR EFFECTS WHEN
A FAILURE MODE OCCURS, OBTAIN THE FOLLOWING INFORMATION. THE
EVIDENCE OF THE FAILURE TO THE OPERATING CREW UNDER NORMALCONDITIONS. THE HAZARDS THE FAILURE MAY POSE TO WORKER SAFETY,
PUBLIC SAFETY, PROCESS STABILITY, OR THE ENVIRONMENT. THE EFFECT
ON PRODUCTION OUTPUT AND MAINTENANCE.
STEP 5 SELECT FEASIBLE AND EFFECTIVE MAINTENANCE TACTICS
:STEP 5 SELECT FEASIBLE AND EFFECTIVE MAINTENANCE TACTICSPREVENTIVE MAINTENANCE TACTICS MUST BE TECHNICALLY
FEASIBLE DEAL EFFECTIVELY WITH THE TECHNICAL CHARACTERISTIC
OF THE FAILURE. COST-EFFECTIVE REDUCING OR AVOIDING PITFALLS INLINE WITH COSTS AND OPERATING CONSTRAINTS.
STEP 6 IMPLEMENT SELECTED TACTICS :STEP 6 IMPLEMENTSELECTED TACTICS ACTIONS NEEDED TO PUT THE MAINTENANCE
TACTICS INTO EFFECT. TWEAKING MAINTENANCE SCHEDULES.
DEVELOPING OR REVISING TASKS INSTRUCTIONS. SPECIFYING SPAREPARTS AND ADJUSTING INVENTORY LEVELS. ACQUIRING DIAGNOSTIC OR
TEST EQUIPMENT. REVISING OPERATION AND MAINTENANCE
PROCEDURES. SPECIFYING THE NEED FOR REPAIR OR RESTORATIONPROCEDURES. CONDUCTING TRAINING IN THE NEW PROCEDURES.
STEP 7 OPTIMIZE TACTICS AND PROGRAM :STEP 7 OPTIMIZE TACTICS
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AND PROGRAM THE OBJECTIVE OF THIS ONGOING ACTIVITIES ARE TO
REDUCE EQUIPMENT FAILURE, IMPROVE MAINTENANCE EFFECTIVENESS,
THE USE OF RESOURCES, IDENTIFY THE NEED TO EXPAND THE REVIEW,AND REACT TO THE CHANGING INDUSTRY OR ECONOMIC CONDITIONS.
STEP 7 OPTIMIZE TACTICS AND PROGRAM :STEP 7 OPTIMIZE TACTICS
AND PROGRAM COMPLIMENTARY ACTIVITIES PERIODIC RE-ASSESSMENT
AND REVISION OF THE RCM REVIEW RESULTS. CONTINUOUS PROCESS OFMONITORING, FEEDBACK, AND ADAPTATION. ANALYZES AND ASSESSES
THE DATA PRODUCED BY PRODUCTION AND MAINTENANCE ACTIVITIES
FOR FAILURE RATES, CAUSES, AND TRENDS. VARIANCES BETWEEN
ACTUAL AND TARGET PERFORMANCE.
RCM KEY SUCCESS FACTORS :RCM KEY SUCCESS FACTORS CLEAR
PROJECT GOALS MANAGEMENT SUPPORT & A COMMITMENT TOINTRODUCE A CONTROLLED MAINTENANCE MANAGEMENT. UNION
INVOLVEMENT GOOD UNDERSTANDING OF RCM PHILOSOPHY BY PLANTSTAFF.
Slide 42:RCM KEY SUCCESS FACTORS PILOT RCM APPLICATIONS TO
DEMONSTRATE SUCCESS & BUILD SUPPORT. SUFFICIENT RESOURCES FOR
BOTH THE REVIEW AND SUBSEQUENT IMPLEMENTATION OF
RECOMMENDATIONS. CLEAR DOCUMENTATION OF RESULTS TOFACILITATE ACCEPTANCE OF RECOMMENDATIONS. INTEGRATION WITH
CONDITION-BASED MAINTENANCE CAPABILITY.
RCM IMPLEMENTATION PHASES :RCM IMPLEMENTATION PHASES
RELIABILITY-CENTERED MAINTENANCE (RCM) :RELIABILITY-
CENTERED MAINTENANCE IS THE PROCESS OF DETERMINING THE MOST
EFFECTIVE MAINTENANCEAPPROACH. AS THE AIRLINE INDUSTRYSHOWED 40 YEARS AGO, RCM CAN NOT ONLY IMPROVE THE RELIABILITY
OF A SYSTEM, IT CAN SIGNIFICANTLY REDUCE THE REQUIRED
MAINTENANCE. RELIABILITY-CENTERED MAINTENANCE (RCM)
RELIABILITY-CENTERED MAINTENANCE (RCM) :RELIABILITY-CENTERED MAINTENANCE (RCM) IN TODAY'S COMPETITIVE WORLD
ECONOMY, THAT TRANSLATES INTO A LOT OF MONEY SAVED, BOTH
FROM REDUCED FAILURES AND REDUCED WORK. A PROPERLY
IMPLEMENTED RCM PROGRAM WILL CONTINUE SAVING MONEY YEAR
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AFTER YEAR.
Slide 46:TO REMAIN COMPETITIVE MOST COMPANIES CAN NO LONGER
AFFORD TO REMAIN ON THE SIDELINES DOING THINGS LIKE THEY'VE
ALWAYS DONE. LET RCM MOVE THE MAINTENANCE PROGRAM INTO THE21ST CENTURY. RELIABILITY-CENTERED MAINTENANCE (RCM)
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Introduction to Reliability-centered Maintenance
This is an excerpt of the first chapter of the book "Reliability-centred Maintenance" by
John Moubray. You may order this book through this website by clickinghere.
1.1 The Changing World of Maintenance
Over the past twenty years, maintenance has changed, perhaps more so than any other
management discipline. The changes are due to a huge increase in the number and variety
of physical assets (plant, equipment and buildings) which must be maintained throughout
the world, much more complex designs, new maintenance techniques and changing viewson maintenance organization and responsibilities.
Maintenance is also responding to changing expectations. These include a rapidly
growing awareness of the extent to which equipment failure affects safety and theenvironment, a growing awareness of the connection between maintenance and product
quality, and increasing pressure to achieve high plant availability and to contain costs.
The changes are testing attitudes and skills in all branches of industry to the limit.
Maintenance people are having to adopt completely new ways of thinking and acting, asengineers and as managers. At the same time the limitations of maintenance systems are
becoming increasingly apparent, no matter how much they are computerized.
In the face of this avalanche of change, managers everywhere are looking for a new
approach to maintenance. They want to avoid the false starts and dead ends which always
accompany major upheavals. Instead they seek a strategic framework which synthesizesthe new developments into a coherent pattern, so that they can evaluate them sensibly and
apply those likely to be of most value to them and their companies.
This book describes a philosophy which provides just such a frame-work. It is calledReliability-centered Maintenance, orRCM.
If it is applied correctly, RCM transforms the relationships between the undertakings
which use it, their existing physical assets and the people who operate and maintain those
assets. It also enables new assets to be put into effective service with great speed,confidence and precision.
This chapter provides a brief introduction to RCM, starting with a look at how
maintenance has evolved over the past fifty years.
1.2 Reliability-centered Maintenance
mailto:[email protected]://www.plant-maintenance.com/books/0831130784.shtmlhttp://www.plant-maintenance.com/books/0831130784.shtmlhttp://www.plant-maintenance.com/books/0831130784.shtmlmailto:[email protected]://www.plant-maintenance.com/books/0831130784.shtml -
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Since the 1930's, the evolution of maintenance can be traced through three generations.
RCM is rapidly becoming a cornerstone of the Third Generation, but this generation can
only be viewed in perspective in the light of the First and Second Generations.
The First Generation
The First Generation covers the period up to World War II. In those days industry was
not very highly mechanized, so downtime did not matter much. This meant that the
prevention of equipment failure was not a very high priority in the minds of mostmanagers. At the same time, most equipment was simple and much of it was over-
designed. This made it reliable and easy to repair. As a result, there was no need for
systematic maintenance of any sort beyond simple cleaning, servicing and lubricationroutines. The need for skills was also lower than it is today.
The Second Generation
Things changed dramatically during World War II. Wartime pressures increased thedemand for goods of all kinds while the supply of industrial manpower dropped sharply.
This led to increased mechanization. By the 1950's machines of all types were morenumerous and more complex. Industry was beginning to depend on them.
As this dependence grew, downtime came into sharper focus. This led to the idea that
equipment failures could and should be prevented, which led in turn to the concept of
preventive maintenance. In the 1960's, this consisted mainly of equipment overhauls doneat fixed intervals.
The cost of maintenance also started to rise sharply relative to other operating costs. This
led to the growth of maintenance planning and control systems. These have helpedgreatly to bring maintenance under control, and are now an established part of thepractice of maintenance.
Finally, the amount of capital tied up in fixed assets together with a sharp increase in the
cost of that capital led people to start seeking ways in which they could maximize the lifeof the assets.
The Third Generation
Since the mid-seventies, the process of change in industry has gathered even greater
momentum. The changes can be classified under the headings of new expectations, newresearch and new techniques.