rcm terminology and concepts

Module 3Module 3

UNIT IUNIT I

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INTRODUCTION TO RCMINTRODUCTION TO RCM

RCM TERMINOLOGY AND RCM TERMINOLOGY AND CONCEPTSCONCEPTS

IntroductioIntroductionn

Module Preview:Module Preview:

FailuresFailuresIntroductionIntroduction

SeveritySeverity

Probability of FailureProbability of Failure

ReliabilityReliability

Types of MaintenanceTypes of Maintenance

Review and SummaryReview and Summary

CriticalityCriticality

RCM TERMINOLOGY AND CONCEPTSRCM TERMINOLOGY AND CONCEPTS

Module Module Objective:Objective:

This module will introduce basic This module will introduce basic concepts and terminology used in concepts and terminology used in the RCM process.the RCM process.



Module Module Objective:Objective:


1. Define Failure Terminology:1. Define Failure Terminology:Functional FailureFunctional Failure

Potential FailurePotential Failure Failure ModeFailure Mode2. Introduce the concepts of 2. Introduce the concepts of SeveritySeverity, ,

Probability of FailureProbability of Failure, and , and CriticalityCriticality and how they are related. and how they are related.


Module Objective:Module Objective: IntroductioIntroductionn

3. Introduce the concept of 3. Introduce the concept of ReliabilityReliability..

4. Define the following maintenance terms:4. Define the following maintenance terms: - Scheduled Maintenance - Unscheduled Maintenance - Scheduled Maintenance - Unscheduled Maintenance - Preventive Maintenance - Corrective Maintenance - Preventive Maintenance - Corrective Maintenance - Proactive Maintenance - Proactive Maintenance - Reactive Maintenance - Reactive Maintenance - Condition Monitoring- Condition Monitoring - Condition Based Maintenance - Condition Based Maintenance

- Conditional Maintenance- Conditional Maintenance


FAILURESFAILURES


FailureFailureDefinitions:Definitions:1.1. FAILURE FAILURE:: An identifiable deviation from a An identifiable deviation from a specified condition that is unsatisfactory to an specified condition that is unsatisfactory to an asset owner or manager.asset owner or manager.

RCM recognizes two types of failures:RCM recognizes two types of failures:

FUNCTIONAL FAILURE -FUNCTIONAL FAILURE - Inability of item Inability of item to perform a specific function within to perform a specific function within specified performance limitsspecified performance limits

POTENTIAL FAILURE –POTENTIAL FAILURE – DefinableDefinable and and detectable condition that indicates a detectable condition that indicates a functional failure will occurfunctional failure will occur


FailureFailureDefinitions:Definitions:

2.2. FAILURE MODE FAILURE MODE -- A specific physical A specific physical condition that causes a particular condition that causes a particular functional failurefunctional failure


SEVERITYSEVERITY


SeveritySeverityDefinition:Definition:

SEVERITYSEVERITY - - A category assigned to a A category assigned to a failure mode based on the impacts of failure mode based on the impacts of its potential effectsits potential effects

… … qualitative measures used to qualitative measures used to categorize the potential effects of categorize the potential effects of failures.failures.


CATEGORY I (CATASTROPHIC)CATEGORY I (CATASTROPHIC) Death or Permanent disability Death or Permanent disability Destruction of system/equipmentDestruction of system/equipment Significant breach of environmental Significant breach of environmental regulation regulation Damage > $1MDamage > $1M

CATEGORY III (MARGINAL)CATEGORY III (MARGINAL) Damage >$10K and < $100KDamage >$10K and < $100K Degraded ability to perform critical missionDegraded ability to perform critical mission Interrupted operationsInterrupted operations

CATEGORY II (CRITICAL)CATEGORY II (CRITICAL) Personal InjuryPersonal Injury Inability to perform primary missionInability to perform primary mission Damage >$100K and < $1MDamage >$100K and < $1M

CATEGORY IV (MINOR)CATEGORY IV (MINOR) Unscheduled maintenance or repairUnscheduled maintenance or repair Damage <$10K Damage <$10K

Example:Example: SeveritySeverity

Severity ClassificationsSeverity Classifications Aircraft Example Aircraft Example

Note: In some circumstances when an item performs a critical function and no Note: In some circumstances when an item performs a critical function and no effective back-up is available, loss of function for a defined period of time could be effective back-up is available, loss of function for a defined period of time could be considered critical or catastrophic. These conditions should be added to the severity considered critical or catastrophic. These conditions should be added to the severity classifications as appropriateclassifications as appropriate


CATEGORY I (CATASTROPHIC)CATEGORY I (CATASTROPHIC) Death or Severe InjuryDeath or Severe Injury Significant Environmental Impact Significant Environmental Impact Loss of availability > 1 week Loss of availability > 1 week Damage > $1MDamage > $1M

CATEGORY III (MARGINAL)CATEGORY III (MARGINAL) Loss of availability > 4 hrs and < 24 hrsLoss of availability > 4 hrs and < 24 hrs Damage >$10K and < $100KDamage >$10K and < $100K

CATEGORY II (CRITICAL)CATEGORY II (CRITICAL) Minor InjuryMinor Injury Loss of availability > 24 hrs and < 7 daysLoss of availability > 24 hrs and < 7 days Damage >$100K and < $1MDamage >$100K and < $1M

CATEGORY IV (MINOR)CATEGORY IV (MINOR) Loss of availability < 4 hrsLoss of availability < 4 hrs Damage <$10K Damage <$10K

Example:Example: SeveritySeverity

Severity ClassificationsSeverity Classifications Plant Equipment Plant Equipment Example Example


PROBABILITY OF PROBABILITY OF FAILUREFAILURE


Probability of FailureDefinition:Definition:

1.1. Probability of failureProbability of failure : : The probability that a The probability that a given failure mode will occur during a defined period.given failure mode will occur during a defined period.

2.2. Acceptable Probability of Failure (PAcceptable Probability of Failure (Paccacc):): The probability of a given failure mode occurring during a defined The probability of a given failure mode occurring during a defined period that is acceptable to a program or asset manager. period that is acceptable to a program or asset manager.

• The more severe the consequences, the lower The more severe the consequences, the lower PPacc acc should beshould be

• Values may be defined by regulatory Values may be defined by regulatory organizations or self imposed (by a program or organizations or self imposed (by a program or asset manager) asset manager)

• Values should be documented prior to analysisValues should be documented prior to analysis


Probability of FailureProbability of FailureDefinition:Definition:

3.3. Actual Probability of Failure Actual Probability of Failure (P(Pactact)): : The The predicted or demonstrated probability of a given failure mode predicted or demonstrated probability of a given failure mode occurring during a defined period in the operating environment.occurring during a defined period in the operating environment.

PPactact can be measured from in-service data or can be measured from in-service data or estimated from statistical failure distributionsestimated from statistical failure distributions


CRITICALITYCRITICALITY


CRITICALITY -CRITICALITY - A prioritization of the A prioritization of the combination of failure severity and failure combination of failure severity and failure frequency (or probability)frequency (or probability)•Sometimes referred to as Sometimes referred to as RiskRisk•Criticality may beCriticality may be documented documented

qualitatively or quantitativelyqualitatively or quantitatively (Ref: MIL-(Ref: MIL-STD-1629)STD-1629)

•Asset managers/Programs may define Asset managers/Programs may define acceptable criticality limitsacceptable criticality limits by use of a by use of a Hazard Risk Matrix. (Qualitative Method)Hazard Risk Matrix. (Qualitative Method)

•Criticality can be used to set priorities Criticality can be used to set priorities for analysis or define acceptable riskfor analysis or define acceptable risk

CriticalityCriticalityDefinition:Definition:


Hazard Risk Matrix:Hazard Risk Matrix:FREQUENCYFREQUENCY

SEVERITYSEVERITY

FREQUENTFREQUENT (A)(A)

>> 1 per 1,000 1 per 1,000 HoursHours

PROBABLEPROBABLE (B) (B)

>> 1 per 10,000 1 per 10,000HoursHours

OCCASIONALOCCASIONAL (C) (C)

>> 1 per 100,000 1 per 100,000HoursHours

REMOTE REMOTE (D)(D)

>> 1 per 1,000,000 1 per 1,000,000HoursHours

IMPROBABLEIMPROBABLE (E) (E)

<< 1 per 1,000,000 1 per 1,000,000HoursHours

CATASTROPHIC (I)CATASTROPHIC (I)

CRITICAL (II)CRITICAL (II)

MARGINAL (III)MARGINAL (III)

MINOR (IV)MINOR (IV)

• Death or Permanent disabilityDeath or Permanent disability• Significant Environmental breach Significant Environmental breach • Damage > $1M, Downtime>2 daysDamage > $1M, Downtime>2 days• Destruction of system/equipmentDestruction of system/equipment

• Personal InjuryPersonal Injury• Damage >$100K and < $1MDamage >$100K and < $1M• Loss of availability > 24 hrs and Loss of availability > 24 hrs and < 7 days< 7 days

• Damage >$10K and < $100KDamage >$10K and < $100K• Loss of availability > 4 hrs andLoss of availability > 4 hrs and < 24 hrs< 24 hrs

• Damage <$10K Damage <$10K • Loss of availability < 4 hrsLoss of availability < 4 hrs

11HIGHHIGH

33HIGHHIGH

44HIGHHIGH

22HIGHHIGH

55HIGHHIGH

88MEDMED

66MEDMED

77MEDMED

99MEDMED

1010LOWLOW

1212ACCEPTACCEPT

1313ACCEPTACCEPT

1515ACCEPTACCEPT

1616ACCEPTACCEPT

1717ACCEPTACCEPT

2020ACCEPT

1919ACCEPT

1414ACCEPT

1111LOWLOW

1818ACCEPTACCEPT

CriticalityCriticality


RELIABILITYRELIABILITY


ReliabilityReliability

RELIABILITY -RELIABILITY - Probability that an Probability that an asset will perform its intended asset will perform its intended function for a specified period of function for a specified period of time under specified operating time under specified operating conditionsconditions

Actual Reliability is a function of the asset’s Actual Reliability is a function of the asset’s design, manufacturing process, usage profile, design, manufacturing process, usage profile, operating environment, and maintenance operating environment, and maintenance program.program.

Definitions:Definitions:


MAINTENANCE MAINTENANCE TERMSTERMS


Types of MaintenanceTypes of MaintenanceDefinition:Definition:

PREVENTIVE MAINTENANCE PREVENTIVE MAINTENANCE – actions – actions performed periodically (or performed periodically (or continuously) prior to functional failure continuously) prior to functional failure (or multiple failure/demand (or multiple failure/demand requirements for hidden failures) to requirements for hidden failures) to achieve the desired level of safety and achieve the desired level of safety and reliability for an itemreliability for an item… … These actions are performed to prevent or These actions are performed to prevent or reduce consequences of failures.reduce consequences of failures.

Due to differences in the way the term Due to differences in the way the term Scheduled MaintenanceScheduled Maintenance is used, this course will is used, this course will attempt to use the term attempt to use the term Preventive MaintenancePreventive Maintenance only only


Types of MaintenanceTypes of MaintenanceDefinitionDefinition

• PROACTIVE MAINTENANCE PROACTIVE MAINTENANCE – any – any tasks used to predict or prevent tasks used to predict or prevent equipment failures.equipment failures.Similar to Similar to Preventive MaintenancePreventive Maintenance except that it except that it generally excludes failure finding type tasks. generally excludes failure finding type tasks. Again, definitions may vary…Again, definitions may vary…



• CORRECTIVE MAINTENANCE CORRECTIVE MAINTENANCE –– repairs repairs or other corrective action taken or other corrective action taken after a failure has occurredafter a failure has occurred

For the purposes of this course, the term For the purposes of this course, the term Unscheduled Unscheduled MaintenanceMaintenance is synonymous with is synonymous with Corrective MaintenanceCorrective Maintenanceand and Reactive MaintenanceReactive Maintenance



• CONDITION MONITORING – CONDITION MONITORING – The use The use of specialized equipment to measure of specialized equipment to measure the condition of equipment.the condition of equipment.

Vibration Analysis, Oil Analysis, and ThermographyVibration Analysis, Oil Analysis, and Thermographyare examples of are examples of Condition MonitoringCondition Monitoring techniques techniques

Predictive Maintenance (PdM) and Prognosis and Health Predictive Maintenance (PdM) and Prognosis and Health Management (PHM) are usually interchangeable with Management (PHM) are usually interchangeable with Condition Monitoring.Condition Monitoring.



• Condition Based Maintenance Condition Based Maintenance – An – An equipment maintenance strategy equipment maintenance strategy based on measuring the condition of based on measuring the condition of equipment in order to assess equipment in order to assess whether it will fail during some whether it will fail during some future period, and then taking future period, and then taking appropriate action to avoid the appropriate action to avoid the consequences of that failure.consequences of that failure.



• Conditional or Opportunity Maintenance Conditional or Opportunity Maintenance –– Maintenance actions conducted as result Maintenance actions conducted as result of a specific condition, or as a result of of a specific condition, or as a result of specific circumstances or events. specific circumstances or events.

Examples of Conditional InspectionsExamples of Conditional Inspections• Hard LandingHard Landing• Unscheduled disassembly Unscheduled disassembly • Power InterruptionPower Interruption• Over/Under VoltageOver/Under Voltage• Lightning strikeLightning strike• Over stressOver stress• Unscheduled or scheduled shut-Unscheduled or scheduled shut-downdown


Proactive MaintenanceProactive Maintenance

Preventive Maintenance (PM)Preventive Maintenance (PM) Unscheduled MaintenanceUnscheduled Maintenance

Corrective Maintenance (CM)Corrective Maintenance (CM)

Reactive MaintenanceReactive Maintenance

Condition Based Maintenance Condition Based Maintenance Condition MonitoringCondition MonitoringPredictive Maintenance Predictive Maintenance Prognosis Health Management (PHM)Prognosis Health Management (PHM)Potential failuresPotential failures

Repairs or corrective actionsRepairs or corrective actionsRun to failureRun to failureFailure has occurredFailure has occurred

Preserves required functionalityReduces unplanned downtime

Requires investment

Fixes failures in unplanned mannerDowntime unpredictable

Addresses only “what’s broken”

RCM determines proper balance of planned and unplanned maintenance,RCM determines proper balance of planned and unplanned maintenance, along with “Other Actions”, to establish a “Failure Management Strategy”along with “Other Actions”, to establish a “Failure Management Strategy”

Scheduled MaintenanceScheduled Maintenance

Types of MaintenanceTypes of MaintenanceSummary:Summary:


Review and Review and SummarySummary

IntroductionIntroduction

RCM Terms & RCM Terms & ConceptsConcepts

– Learning ObjectivesLearning Objectives

– FailuresFailures– Severity Severity – Probability of FailureProbability of Failure– CriticalityCriticality– ReliabilityReliability– Maintenance TermsMaintenance Terms

Module ObjectiveModule Objective– Introduce the primary Introduce the primary

terminology and basic concepts terminology and basic concepts used in RCMused in RCM


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Unit II Module 1 RCM Process Overview

rcm terminology and concepts

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