5 december 2011 living probabilistic asset management dr.ir. j.a. van den bogaard
TRANSCRIPT
5 december 2011
Living Probabilistic Asset Management
Dr.ir. J.A. van den Bogaard
Living Probabilistic Asset Management
2 5 december 2011Ministerie van Verkeer en Waterstaat
3,510-3
[-/vraag]
1,010-2
[-/vraag] 1,010-2
[-/vraag]
Living Probabilistic Asset Management
3 5 december 2011Ministerie van Verkeer en Waterstaat
From PSA to LPAM
• PSA proven, mature methodology in Nuclear and Petro-Chemical Industry, which is routinely applied
• PSA focuses on Safety while critical performance characteristics of infrastructure demands focus on RAMS aspects
• PAM extends the focus on safety to RAMS
• Systems and operations change over time need to be taken into account:– Physical changes in the design of a system– Changes in operating conditions– Improvements in the understanding of system behaviour in fault conditions– More system specific data become available
• Keeping the PAM useful over time it needs to be updated making it a Living PAM
Living Probabilistic Asset Management
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Definition LPAM
A living PAM can be defined as a PAM analysis of a system, which is updated, if necessary, to reflect the current built and operational features and is documented in such a way that each aspect of the model can be directly related to existing system information, operating conditions, system documentation or the analysts’ assumptions in the absence of such information.
Living Probabilistic Asset Management
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Characteristics of LPAM
• Framework for the process to obtain, maintain and optimize the reliability level
• Deming-circle Principle (plan-do-check-act) • Complete mix of in-depth knowledge of technical systems, reliability
analysis, maintenance • Qualitative/Quantitative approach• Reliability, Availability, Maintainability, Safety (RAMS)
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Scope of LPAM
LPAM
Organization PerformanceAnalysis
Contracts
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Implementation and operational process LPAM
ACTDesign Modifications
Modify FT andCheck Target
CheckOver-all and
Component Performance
PLANSpecify ModificationsInstruct Contractors
DOImplement Modifications
Perform regularMaintenance
INITIAL PHASE
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Phase 0: Initial Phase
1. System and function analysis2. Defining RAMS requirements3. Perform Qualitative and Quantitative Risk Analysis4. Define As-Is situation5. Define As-Wished situation6. Define differences and plan activities7. Translate to LPAM process
• Process description• Defining necessary contral and operational organisation• Define contracts (DBFM contractual aspects)
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Total probability of failure
Probabilities of events result from fault tree analysis
Fault tree 1 Fault tree 2 Fault tree 3Fault tree
…Fault tree n
Event tree
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Topics in QRA
• Component and system reliability• Common Cause Failure• External Causes of Failure
– Lightning– Fire– Internal flooding– Etc.
• Human reliability• Software reliability
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Phase 1: Maintenance Planning
Maintenance plan should include/respect all assumptions made in the QRA’s.
Including:• Maintenance strategies (CM, PM, CM)• Inspection strategies/intervals• Testing strategies/intervals• Recovery and test procedures• Repair times• Stock policy
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Phase 2: Performing Maintenance
In the DO phase modifications are implemented and regular maintenance is performed according to the maintenance plans. These activities consist of the execution of tests, inspections, revisions, repairs, replacements and the system modifications, as planned in the previous phase.
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Phase 3: Monitoring Process
In the CHECK phase the overall system, components, maintenance en organizational performance of the system is monitored. Monitoring focuses on:
– All failures, errors, disruptions and observations in process or system– All differences with respect to the assumptions in the risk analysis (repair
times, inspection intervals, test intervals)– Effectiveness of all tests and inspections– Gathering information from tests and inspections for trend analysis of
failure frequencies
– Observations on human errors during maintenance and operations.
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Phase 4: Analyzing and Adjusting Risk Analyses
In the ACT phase the probability of failure of the system is calculated with the new input from the check phase and is assured that the system still complies with the probability target.
The final result, i.e. failure probability of the system, is compared with the target and if the target is met no additional design measures are necessary. But if the outcome does not comply with the target, the system has to be modified. Next to changing the hardware physically, also measures like reducing repair times, shortening test intervals or improve skills can be taken. These modifications will have to be evaluated again, until the probability target is met. This process constitutes a small loop within the ACT phase.
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Organization of the LPAM Process
Important aspects:• Implementation of LPAM is usually carried out by a project team• After implementation the maintenance organisation becomes
responsible for the quality and effectiveness of LPAM• It is a mistakte to think that the organisation is in control after the
initial phase• Sufficient resources should be available• Support from management is key to success• Training and education programs should be available and
implemented• Other important issues in this phase are the role of (sub-)contractors,
training of operation and training of maintenance activities and the interpretation of feedback from the maintenance activities the risk analyses.
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Documentation
• Results, conclusions and recommendations traced back to the design, operation and assumptions used in the analysis.
• The documentation needs to include details of the design and operation of the system and details of the analysis that form the basis for the models used in LPAM.
• The justification for the data used for initiating event frequencies, component failure probabilities, common cause failure probabilities, human error probabilities, etc. should be provided. All numerical values should be traceable, back to the source data or models.
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LPAM with respect to networks
Application LPAM on infrastructural networks
• Complexity• Criticality• Costs
Level of detailof analyses
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Questions?