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PACP® Based Asset Management
Objectives of Asset Management
• Maintain function or level of service as cost
effectively as possible
• Maintain individual components (assets) at lowest
life cycle cost possible
Asset Management in Wastewater Systems
Key asset management questions:
− What pipes, manholes, and laterals do we own?
− Where are these assets located?
− What are their materials, dimensions, depth, and ground
cover?
− What is the condition of each asset?
− What other community assets would be affected by
failure of a particular asset?
− Which assets are critical to sustained performance?
− What are my best O&M and CIP investment strategies?
− What will be the rehabilitation cost?
− What effect will this have upon the utility budget?
− How should all of this be communicated to stake holders?
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PACP in Asset Management
PACP can assist in developing an asset management
plan by collecting asset information such as:
Pipe segment length
Relative location details
Pipe size
Pipe shape
Pipe material
Upstream manhole data
Pipe segment lateral data
Consequence of failure
Defect codes (Structural and
O&M)
– Condition grades
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Risk in Asset Management
Risk = Calculation that takes into account
• Physical condition
• The impact of failure to
− System performance
− Stakeholders
Risk in Asset Management
Risk
• Likelihood of something bad happening
and
• Severity of consequence(s) of failure
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Risk in Asset Management
Risk = LoF x CoF
• Likelihood of Failure (LoF) - Probability of failure of
an asset
• Consequence of Failure (CoF) - Direct and indirect
impacts that would result from an asset failure
Likelihood Of Failure (LoF)
• PACP condition grades can determine segment scores
• Segment scores can be used to calculate Likelihood of
Failure for pipelines
• The Modified PACP Quick Rating based upon highest
grade defect observed within a particular pipe
segment
Appendix C – PACP Condition Grading System
PACP Grading System for Pipelines, Manholes and Laterals
5 – Most significant defect grade
4 – Significant defect grade
3 – Moderate defect grade
2 – Minor to moderate defect grade
1 – Minor defect grade
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Pipe Rating System
PACP Quick Rating
10 to 14 =A
15 to 19 = B
20 to 24 = C
Etc.
10 to 14 =A
15 to 19 = B
20 to 24 = C
Etc.
Likelihood of Failure Rules
An asset’s Likelihood of Failure is determined
based on the following scenarios:
• No condition assessment data is available
• Condition assessment data is available and there
are no defects
• There are no more than 9 occurrences of the
highest condition grade
• The second character is a letter (indicating more
than 9 occurrences)
In all cases we divide the first two digits of the quick rating by 10
Calculate LoF
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Calculate LoF
Consequence of Failure (CoF)
• Direct and indirect impacts on the vicinity and
community due to a potential asset failure
• Expressed as “Triple Bottom Line” (TBL)
o Economic Impacts
o Social Impacts
o Environmental Impacts
Consequence of Failure (CoF)
Social costs
Sustainability
Environmental
costs
Economical
costs
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Economical Impacts
• Impact of Direct and Indirect economic losses
o Direct costs
– Asset Repairs
– Legal Fees
– Fines
o Indirect costs
– Property Values
– Increased Insurance Rates
– Utility's Credibility
• Typically expressed in dollars and include property
damage, repair cost, and production loss, etc.
Social Impacts
• Impact on Society due to asset failure
• Factors include
o Number of properties/clients affected
o Types of affected properties (hospitals, schools,
businesses, parks, “critical services”, etc.)
o Duration of Failure
o Utility’s Credibility
o Public Health and Safety
• In addition, there must be consideration for safety
issues (i.e. public exposure to health-threatening
problems, injuries, or even fatalities)
Environmental Impacts
• Impact to ecological conditions occurring as a result
of asset failure
• Environmentally cost considerations based on
o Proximity to wetlands and waterways
o Federal Emergency Management Agency (FEMA) flood
zones
o Possible contamination of potable water sources
o Sensitivity of nearby soils
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Rating Methodology
• 56 inch combined trunk sewer 100 feet downstream
of a Combined Sewer Overflow (CSO) that crosses a
body of water
Vs.
Lower CoF
Higher CoF
• 8 inch sanitary sewer at the upstream end of the
system that only serves one resident
Rating Methodology
• Considers locational and demographical information
o
o
o
o
o
Network Position
Location of Pipe
Proximity to Environmentally Sensitive Features
Service to customer of significant importance
Accessibility for maintenance and inspection
• A good GIS map helps to determine these
considerations
• CoF assigned on a scale from 1 to 6
• Assets with no CoF assigned are given a value of 0
(Zero)
CoF Examples
• CoF Descriptions and Associated Factors
• Examples include
o
o
o
o
o
o
o
Pipe Depth
Relative Network Position of the Pipe
Pipe Diameter
Location of Pipe
Distance between Pipe and Waterway
Customers of High Importance
Accessibility
The system owner must decide
upon CoF factors and weighting
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Pipe Depth
Typically an economic consideration since deeper pipe
is generally more expensive to repair/replace
* Assets
with no CoF assigned shall be given a value of 0 (Zero)
Relative Network Position of Pipe
• Pipe Diameter
o Economic – Costs more to repair, replace, and rehabilitate
o Social – Impacts more customers
o Environmental – impacts to sensitive geographical area
• Relative Network Position
Sum of relative position of all pipes discharging to an
upstream structure
Pipe Diameter
• Affects Economic, Environmental and Social costs
• Larger diameter pipes generally
− Serve more customers
− Cost more to rehabilitate
* Assets with no CoF assigned shall be given a value of 0 (Zero)
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Relative Network Position of Pipe
Relative Network Position of Pipe
Location of Pipe
GIS based maps with layers including street network,
buildings, waterways and other datasets can be utilized
to assign Consequence of Failure based on surface
location
Location of Pipe
• Disruption to the community and the cost of managing
emergency repairs of a pipe
• Accessibility for repair, rehabilitation or replacement in case
of emergency
• Pipe failure on a major road causes more disruption to traffic
compared to failure of a pipe on a local road
* Assets with no CoF assigned shall be given a value of 0 (Zero)
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Proximity to Environmentally Sensitive Features
• Consequence of Failure factor is set based on the distance
between a pipe and an environmentally sensitive feature
• Factor affected by the nature of the sensitive environment
• GIS can be set-up to assign CoF based on distance to
environmentally sensitive features
Service to Customer of Significant Importance
• Hospitals, schools, manufacturing facilities,
emergency services, etc., as determined by utility
• Providing uninterrupted service to these facilities
may be a priority for the utility
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Accessibility for Maintenance/Inspection
• Response time for a service crew may be significantly
higher if access is difficult
• Failure may cause significant damage to the
environment as well as private properties due to
delays in response
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Sample Calculation of Overall CoF
4.03
Enter Consequence of Failure value
in Field 22 of the PACP Inspection
Form Header Section
Managing Asset Risk
• Risk matrix provides a basis for a maintenance and
rehabilitation program
• Overall risk a function of LoF and CoF
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Appendix D – PACP ® Based Risk Management
Considers PACP Role Regarding Risk Management in Asset
Management
Managing Asset Risk
• CoF and LoF have a range between 0 and 6
• A score of 0 (LoF or CoF) represents a data
gap
− Information should be promptly collected
− Do not use/graph 0 scores!
• On the graph
o The green area represents assets with lower
risk
o The red area represents assets with higher
risk; resources should be focused on
rehabilitating assets that fall in the red area
• Non-zero risk scores can be used to
prioritize projects
Collect asset condition information
Sample Asset Management Plan
Graph this data to help set priorities
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Managing Asset Risk (Examples)
5.1, 4.4
2.4, 4.0
2.1, 3.0
4.1, 2.8
2.1, 2.5
4.4, 2.1
Managing Asset Risk (Examples)
$40,000 available for rehab
$25,000 available for rehab
$20,000 available for rehab
5.1, 4.4
2.4, 4.0
2.1, 3.0
4.1, 2.8
2.1, 2.5
4.4, 2.1
Successful Asset Management Results
• Shift from emergency response to strategic riskbased management of critical assets
• Reduce the number of asset failures
• Minimize the negative impacts of failures when they
occur
• Improve performance & reliability of the system
• Manage O&M costs more accurately
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Questions?
More Information?
Ted DeBoda, PE
[email protected]
Jane Bayer
[email protected]
NASSCO, Inc.
(410) 442-7473
WWW.NASSCO.ORG
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