Copyright 2015 - GLS Consulting (Pty) Ltd Printed with permission. 1 Alexander Sinske, CTO GLS Consulting [email protected]Overview of presentation Overview of presentation Investment planning: Water pipes Principles & Definition Likelihood of Failure Consequence of Failure Roll-up of results Case Study: Overstrand Municipality Asset management alignment Long term investment planning Conclusion Investment planning: Water pipes Principles & Definition Likelihood of Failure Consequence of Failure Roll-up of results Case Study: Overstrand Municipality Asset management alignment Long term investment planning Conclusion
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Overview of presentation · Alexander Sinske, CTO GLS Consulting [email protected] Overview of presentation Investment planning: Water pipes Principles & Definition Likelihood of Failure
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Copyright 2015 - GLS Consulting (Pty) Ltd Printed with permission. 1
Investment planning: Water pipesPrinciples & DefinitionLikelihood of FailureConsequence of FailureRoll-up of resultsCase Study: Overstrand MunicipalityAsset management alignmentLong term investment planningConclusion
Investment planning: Water pipesPrinciples & DefinitionLikelihood of FailureConsequence of FailureRoll-up of resultsCase Study: Overstrand MunicipalityAsset management alignmentLong term investment planningConclusion
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Investment planning: Water pipesInvestment planning: Water pipes
Input- CAPEX- Development planning- Planned replacement and upgrades- Condition assessment
Output- Failure incidents- OPEX- Interruption: Duration x No of consumers = SID - (Service Interruption Delay)- Water loss
Input- CAPEX- Development planning- Planned replacement and upgrades- Condition assessment
Output- Failure incidents- OPEX- Interruption: Duration x No of consumers = SID - (Service Interruption Delay)- Water loss
PrinciplesPrinciples
Pipe replacement prioritization (PRP)Probability of Failure (PF)Consequence (C)PF x C = RISK (in monetary terms)Intervention: Replacement / Refurbishment reduces- Risk- OPEX- SID- Water loss
Pipe replacement prioritization (PRP)Probability of Failure (PF)Consequence (C)PF x C = RISK (in monetary terms)Intervention: Replacement / Refurbishment reduces- Risk- OPEX- SID- Water loss
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PRP: DefinitionPRP: Definition
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PRP: Likelihood of failure (LF)PRP: Likelihood of failure (LF)
Typical Contributing Factors- Nominal diameter- Reserve water pressure ratio- Catalogue remaining useful life- Required (forced) upgrade- High failure frequency- DMA zone leakage volume (where available)- Undesired pipe material (e.g. AC)- Assessed Condition (where available)- Pipe material in combination with geology- High corrosion potential for steel pipes- High static-dynamic pressure range
Typical Contributing Factors- Nominal diameter- Reserve water pressure ratio- Catalogue remaining useful life- Required (forced) upgrade- High failure frequency- DMA zone leakage volume (where available)- Undesired pipe material (e.g. AC)- Assessed Condition (where available)- Pipe material in combination with geology- High corrosion potential for steel pipes- High static-dynamic pressure range
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Rating of Likelihood of failure (e.g.)Rating of Likelihood of failure (e.g.)
Reserve Pressure Ratio = Reserve Pressure Ratio =
Property Criteria Rating(<=) (1..5)
Reserve Pressure Ratio 0.25 1
Reserve Pressure Ratio 0.50 2
Reserve Pressure Ratio 0.75 3
Reserve Pressure Ratio 0.99 4
Reserve Pressure Ratio >0.99 5
Rating of Likelihood of failure (e.g.)Rating of Likelihood of failure (e.g.)
Required Upgrade (master plan item)Required Upgrade (master plan item)
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Likelihood of failure – failure frequencyLikelihood of failure – failure frequency
Likelihood of failure – typical weightingLikelihood of failure – typical weighting
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PRP: Consequence of failure (CF)PRP: Consequence of failure (CF)
Typical Contributing Factors- High damage cost to consumer due to water
pressure- High damage cost to consumer due to flow- High repair cost based on pipe cost function- Flooding due to steep geography - Strategic location (e.g. CBD, HOS, IND)- Lack of network redundancy
Typical Contributing Factors- High damage cost to consumer due to water
pressure- High damage cost to consumer due to flow- High repair cost based on pipe cost function- Flooding due to steep geography - Strategic location (e.g. CBD, HOS, IND)- Lack of network redundancy
Rating of Consequence of failure (e.g.)Rating of Consequence of failure (e.g.)
High repair cost (due to location)High repair cost (due to location)
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Consequence of failure – typical weightingConsequence of failure – typical weighting
LF – typical final factor visualizationLF – typical final factor visualization
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CF – typical final factor visualizationCF – typical final factor visualization
PRP – typical final factor visualizationPRP – typical final factor visualization
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PRP: Roll-up of resultsPRP: Roll-up of results
To facilitate interpretation of PRP results, roll-up of results to areas is supported by- Political region- Roll-up area
Roll-up areas typically consist of - Bulk systems for Bulk Pipes- Suburbs for Network Pipes- Street block polygons for Network Pipes
The pipe length weighted average PRP is calculated for each areaA ranking index is calculated (PRP%)
To facilitate interpretation of PRP results, roll-up of results to areas is supported by- Political region- Roll-up area
Roll-up areas typically consist of - Bulk systems for Bulk Pipes- Suburbs for Network Pipes- Street block polygons for Network Pipes
The pipe length weighted average PRP is calculated for each areaA ranking index is calculated (PRP%)
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Case Study: Overstrand MunicipalityCase Study: Overstrand Municipality
PRP Reports- 2010- 2012- 2014
PRP Reports- 2010- 2012- 2014
Overstrand – failure frequency analysisOverstrand – failure frequency analysis
Logged pipe failure important source of information to identify where pipe failures are likely to occur in futurePipe sections might have been replaced, but underlying reason for failure might not have been resolved Future failures are likely to occur again in adjacent sections until total replacement of street block or areas has been done
Logged pipe failure important source of information to identify where pipe failures are likely to occur in futurePipe sections might have been replaced, but underlying reason for failure might not have been resolved Future failures are likely to occur again in adjacent sections until total replacement of street block or areas has been done
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Overstrand – failure frequency analysisOverstrand – failure frequency analysis
Geo-coding process followed to map incidents to modelled pipesTypical values recorded between 0 and 29 incidents/km/aFailures where the correlated pipe was replaced within the same year or after the failures was recorded, were excluded. This assumes that the reason for the failure related to the old pipe was resolved
Geo-coding process followed to map incidents to modelled pipesTypical values recorded between 0 and 29 incidents/km/aFailures where the correlated pipe was replaced within the same year or after the failures was recorded, were excluded. This assumes that the reason for the failure related to the old pipe was resolved
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Analysis of post-PRP replacement areasAnalysis of post-PRP replacement areas
Replacements areas post PRP implementation (Betty’s Bay)Replacements areas post PRP implementation (Betty’s Bay)
Analysis of post-PRP replacement areasAnalysis of post-PRP replacement areas
Length-weighted replacement priority (PRP) before replacementLength-weighted replacement priority (PRP) before replacement
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Analysis of post-PRP replacement areasAnalysis of post-PRP replacement areas
Projected replacement cost (2014 pricing)Adjacent areas considered also for replacementProjected replacement cost (2014 pricing)Adjacent areas considered also for replacement
Analysis of post-PRP replacement areasAnalysis of post-PRP replacement areas
Replace Cost vs Repair Cost break-even point (years) @ R25 000 per typical burstReplace Cost vs Repair Cost break-even point (years) @ R25 000 per typical burst
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A further step is to provide an aligned technical approach with Asset Management Principles and provide an absolute measure of need of replacement, not just rankingResult can be used to compare different models with each otherFrom existing PRP results, Failure Modes are analysed independently of each other to determine the final corrected Remaining Useful Life (RUL)
A further step is to provide an aligned technical approach with Asset Management Principles and provide an absolute measure of need of replacement, not just rankingResult can be used to compare different models with each otherFrom existing PRP results, Failure Modes are analysed independently of each other to determine the final corrected Remaining Useful Life (RUL)
The independent Criticality Grade for a pipe is determined from the existing PRP data.Risk Exposure (RE) can for example be defined as Criticality Grade x (RULmax-RUL)(of the worst failure mode)Roll-up of RE and RUL also possible to street blocks
The independent Criticality Grade for a pipe is determined from the existing PRP data.Risk Exposure (RE) can for example be defined as Criticality Grade x (RULmax-RUL)(of the worst failure mode)Roll-up of RE and RUL also possible to street blocks
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RUL correction algorithmRUL correction algorithm
Verification against condition-based RUL bandsVerification against condition-based RUL bands
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Long term investment planningLong term investment planning
Focusses on simulating annual replacements highlighting spending a PRP budget efficientlyMinimize SID: Non-service minutes due to replacements or repairs per total number of connections in areaMinimize predicted number of theoretical failures (OPEX)Optimize CAPEX for condition assessment
Focusses on simulating annual replacements highlighting spending a PRP budget efficientlyMinimize SID: Non-service minutes due to replacements or repairs per total number of connections in areaMinimize predicted number of theoretical failures (OPEX)Optimize CAPEX for condition assessment
PRP provides key input to engineering inspection, refurbishment and replacement processes.PRP should be used for inspection or guide for replacement, not blindly implemented. Pressure management should also be considered in high pressure areas. PRP programme implemented at Overstrandshowing success. Need longer failure record.Asset management alignment as well as long term investment planning provides valuable future extensions to PRP
PRP provides key input to engineering inspection, refurbishment and replacement processes.PRP should be used for inspection or guide for replacement, not blindly implemented. Pressure management should also be considered in high pressure areas. PRP programme implemented at Overstrandshowing success. Need longer failure record.Asset management alignment as well as long term investment planning provides valuable future extensions to PRP
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