United States Office of Research and EPA/600/R-05/038
Environmental Protection Development March 2005
Agency Washington, DC 20460
xvEPA
White Paper on
Improvement of Structural
Integrity Monitoring for
Drinking Water Mains
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EPA/600/R-05/038
March 2005
White Paper on Improvement
of Structural Integrity Monitoring
for Drinking Water Mains
by
Michael D. Royer
Urban Watershed Management Branch
Water Supply and Water Resources Division
National Risk Management Research Laboratory
Edison, New Jersey 08837-3679
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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Notice
The U.S. Environmental Protection Agency (EPA) through its Office of Research
and Development (ORD) has prepared this document as an in-house effort. It
has been subjected to the Agency's peer and administrative review and has been
approved for publication as an EPA document. Mention of trade names or
commercial products does not constitute endorsement or recommendation for
use. Any opinions expressed in this paper are those of the author and do not,
necessarily, reflect the official positions and policies of the EPA.
in
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with
protecting the Nation's land, air, and water resources. Under a mandate of
national environmental laws, the Agency strives to formulate and implement
actions leading to a compatible balance between human activities and the ability
of natural systems to support and nurture life. To meet this mandate, EPA's
research program is providing data and technical support for solving
environmental problems today and building a science knowledge base necessary
to manage our ecological resources wisely, understand how pollutants affect our
health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's
center for investigation of technological and management approaches for
preventing and reducing risks from pollution that threaten human health and the
environment. The focus of the Laboratory's research program is on methods and
their cost-effectiveness for prevention and control of pollution to air, land, water,
and subsurface resources; protection of water quality in public water systems;
remediation of contaminated sites, sediments and ground water; prevention and
control of indoor air pollution; and restoration of ecosystems. NRMRL
collaborates with both public and private sector partners to foster technologies
that reduce the cost of compliance and to anticipate emerging problems.
NRMRL's research provides solutions to environmental problems by: developing
and promoting technologies that protect and improve the environment; advancing
scientific and engineering information to support regulatory and policy decisions;
and providing the technical support and information transfer to ensure
implementation of environmental regulations and strategies at the national, state,
and community levels.
This publication has been produced as part of the Laboratory's strategic
long-term research plan. It is published and made available by EPA's Office of
Research and Development to assist the user community and to link researchers
with their clients.
Sally Gutierrez, Acting Director
National Risk Management Research Laboratory
IV
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Abstract
The improvement of water main structural integrity monitoring (SIM) capability as
an approach for reducing high risk drinking water main breaks and inefficient
maintenance scheduling is explored in this white paper. Inadequate SIM
capability for water mains can cause repair, rehabilitation, or replacement (R3) to
be scheduled either late or early. Late R3 can allow serious deterioration, main
breaks, and their associated consequences to occur. Early R3 is inefficient,
which adversely affects system maintenance priorities and economics. Existing
SIM technologies inadequately characterize various combinations of pipe
materials, configurations, and failure modes. Fortunately, substantial research to
improve SIM is underway or planned, but mostly for high risk, non-drinking water
applications. A systematic effort by EPA and other Federal agencies, in
cooperation with relevant stakeholders, is recommended to identify, prioritize,
and capitalize on opportunities to accelerate SIM capability improvement.
Acceleration of SIM improvement research is especially important at this time,
since: (1) for the next 30+ years a steep rise in R3 decision-making is projected
for our aging water mains; (2) multiple technology transfer, collaboration, and
leveraging opportunities exist; and, (3) SIM capability improvement takes time.
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Table of Contents
Notice iii
Foreword iv
Abstract v
List of Tables viii
Acronyms and Abbreviations ix
Acknowledgments xi
Section 1: Introduction 2
Problem summary 2
Scope of the white paper 4
Section 2: Detailed Problem Statement 5
Description, causes, and risks of water main breaks 5
Magnitude of the water main break problem 10
The need for improved SIM technology 11
Section 3: Public Benefits from SIM Improvements 13
Section 4: The Challenges of Improving SIM Capability 17
The technical challenge 17
The value challenge 20
Section 5: Opportunities for SIM Capability Improvement 23
Overview 23
Opportunities to improve SIM capability 23
Section 6: Conclusions and Recommendations 33
References 36
Appendices 40
Appendix 1. Examples of Recent High Consequence Main Breaks .... 40
Appendix 2.1 Examples of Current SIM Research for Drinking Water
Conveyance Systems 42
VI
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Appendix 2.2 Current/Recent SIM Research for Non-Drinking Water
Pipelines that is Potentially Applicable to Drinking Water
Conveyance Systems 43
Appendix 2.3 Research for Non-pipeline Applications Relevant to SIM
Improvement 45
Appendix 2.4 Examples of Smart/Intelligent Devices & Systems 46
Appendix 3. Examples of Interagency Collaboration Opportunities 47
Vll
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List of Tables
Table 1. Main Break Occurrence Factors 6
Table 2. Example High Consequence Main Break Scenarios 7
Table 3. Types of Adverse Effects from Water Main Breaks 8
Table 4. Summary of Main Break Incidents Affecting Drinking Water Quality . 9
Table 5. Performance Weaknesses of Structural Integrity Monitoring
Approaches 12
Table 6. Functional & Program Benefits of Effective & Affordable Inspection
14
Table 7. A Conceptual Estimate of Economic Benefits & Acceptable Costs of
Main Break Prevention 15
Table 8. SIM Generic Sub-task List 18
Table 9. Examples of Problem Fragmentation 19
Table 10. Summary of NDE-method Issues that Affect Technique Selection for
Various Water Pipe Materials (Dingus et al., 2002) 24
Table 11. Selected SIM Research Needs for Drinking Water Mains 26
Table 12. Research Issues for Improving Four SIM Approaches 28
Table 13. Examples of Potentially Preventable Types of Main Breaks 29
Table 14. Opportunities for Intra-EPA/ORD Research Collaboration 32
Vlll
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Acronyms and Abbreviations
P change in probability of a pipe failure
ABPA American Backflow Prevention Association
AC asbestos concrete
AWWA American Water Works Association
AwwaRF American Water Works Association Research Foundation
B benefit
C cost
CBO Congressional Budget Office
CF consequences of failure
CI cast iron
DI ductile iron
DOC U.S. Department of Commerce
DOD U.S. Department of Defense
DOE U.S. Department of Energy
DOT U.S. Department of Transportation
ECCP electrically conductive composite pipe
EPA U.S. Environmental Protection Agency
ETV Environmental Technology Verification program (EPA)
F coverage by inspection (temporal, spatial, or failure mode)
FLC Federal Laboratory Consortium
FRP fiber glass reinforced plastic
GSA General Services Administration
FIDPE high density polyethylene
TCP instrumented cathodic protection
MFL magnetic flux leakage
MILI mobile, in-line inspection
MNII mobile, non-intrusive inspection
NASA National Aeronautics and Space Administration
NCER National Center for Environmental Research
NDE nondestructive evaluation
NETL National Energy Technology Laboratory (DOE)
NHSRC National Homeland Security Research Center
NIST National Institute of Standards and Technology
NRMRL National Risk Management Research Laboratory (EPA)
NSF National Science Foundation
NTIAC Nondestructive Testing Information Analysis Center (DOD)
OPS Office of Pipeline Safety (DOT)
ORD Office of Research and Development (EPA)
ORNL Oak Ridge National Laboratory (DOE)
OSP Office of Science Policy (EPA)
IX
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P probability of pipe failure
PCCP prestressed concrete cylinder pipe
PE polyethylene
POD probability of detection of a critical flaw
PTA pipeline test apparatus (EPA Facility, Edison, NJ)
PVC polyvinyl chloride
R3 repair, rehabilitation, or replacement
R,D,T,&V research, development, testing, and verification
RFP request for proposals
S steel
SBIR Small Business Innovation Research program (multiple agencies)
SCA structural condition assessment
SCADA supervisory control and data acquisition
SCNGO Strategic Center for Natural Gas and Oil (DOE)
SIM structural integrity monitoring
USER U.S. Bureau of Reclamation
UWMB Urban Watershed Management Branch (EPA)
V value
Vc critical value
WERF Water Environment Research Foundation
WSWRD Water Supply and Water Resources Division (EPA)
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Acknowledgments
The assistance received from those who reviewed and commented on the white
paper at various stages of its preparation is gratefully acknowledged. These
reviewers include Steve Allbee, Dr. Benjamin L. Blaney, Dr. Neil S. Grigg,
Dr. Asim B. Ray, Kenneth Rotert, Dr. Raymond L. Sterling, Daniel A. Sullivan,
Anthony N. Tafuri, and Joyce Perdek Walling. Editorial reviews were provided by
Jatu Bracewell and Candie M. Ferrazzoli. Reviewers' comments were
constructive and resulted in substantial improvements to the final white paper.
The inspiration, guidance, and support for the white paper that was provided by
James J. Yezzi, Jr. and Anthony N. Tafuri are also gratefully acknowledged.
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Section 1: Introduction
The improvement of water main structural integrity monitoring (SIM) capability as an
approach for reducing high risk drinking water main breaks and inefficient maintenance
scheduling is explored in this white paper. Structural integrity1 of water mains2 refers to
the soundness of the pipe wall and joints for conveying water to its intended locations
and preventing egress of water, loss of pressure, and entry of contaminants. SIM is
the systematic detection, location, and quantification of pipe wall and pipe joint damage
and deterioration (e.g., wall thinning, cracking, bending, crushing, mis-alignment, or
joint separation) of installed drinking water mains. Effective SIM enables
determination of the present condition and the deterioration rate of the pipe. Present
condition for a particular pipe location is determined by a single measurement of a
structural parameter. Deterioration rate for a particular pipe location is determined by
periodic measurement of a structural parameter. If the measured parameter reaches a
pre-determined unacceptable level, then actions can be taken such as (a) small repairs
to forestall accelerated deterioration, and much larger repairs later or (b) repair,
rehabilitation, or replacement (R3) to prevent failures and associated damages.
Conversely, if a measured parameter is at an acceptable level, then R3 can be safely
deferred. If suitable failure models exist, SIM data on present condition and
deterioration rate may also be useful for estimating future structural condition and
remaining service life, and for optimizing inspection frequencies.
Problem summary
The lack of cost-effective SIM capability for water mains can cause R3 to be scheduled
either too early or too late. Either error can cause adverse effects.
D Late scheduling of R3 can occur when sparse or inaccurate structural integrity
data cause under-estimation of pipe deterioration and/or loading. Late
scheduling of R3 allows potentially preventable main breaks to occur.
Particularly undesirable are high risk main breaks, which can cause: (1) sudden
and significant losses of water and pressure, (2) serious health or drinking water
quality effects to customers, (3) other adverse effects to critical customers, or (4)
1 Excluded from consideration here are tuberculation and scale formation that clog the bore of the
pipe, leaching of pipe or liner constituents into the water, and permeation of contaminants through the pipe
wall, coatings, linings, or gaskets. Also excluded is the structural integrity of pumps or valves.
2 "Water mains" refer here to raw water transmission mains and treated water transmission,
arterial, or distribution water mains, but not service lines. A raw water transmission main transports raw
water from source to the treatment plant. A treated water transmission main transports water from the
plant to storage or directly to an arterial main. Arterial mains transport treated water to the distribution
mains from the treatment plant or storage. The distribution mains transport water to the service lines,
which transport the water to the end user. For a given system the transmission mains are typically larger
in diameter, straighter, and have fewer connections than the distribution mains (Smith et al., 2000).
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major damage to the surroundings. A key premise of this paper is that high risk
main breaks can be reduced by monitoring pipe deterioration more frequently,
comprehensively, and/or accurately, and then using the collected data to
generate more accurate and timely scheduling of pre-failure R3.
Premature scheduling of R3 can occur when an inadequate quantity or quality of
structural integrity data causes decision-makers to over-estimate the areal
extent and or/the severity of pipe deterioration. If the actual condition of the pipe
can be accurately determined by inspection, then selective R3 on a small fraction
of the pipe becomes an option when it is the more economical way to address
the problem.
Both the cost of high risk main failures and the inefficiency of premature
replacement exacerbate the funding gap between current and required spending
for capital, operating, and maintenance expenditures. The size of the funding
gap has been estimated by EPA at $45 billion to $263 billion (i.e., approximately
$2.3 billion to $13 billion per year) for the 20-year period from 2000 to 2019.
(U.S. EPA, 2002, b & c; Congressional Budget Office (CBO), 2002)
Numerous SIM options already exist for drinking water mains, but these options have
many shortcomings. Various combinations of pipe materials, configurations, and failure
modes are not adequately or economically characterized by existing SIM technology.
A substantial amount of research, development, testing, and verification (R,D,T,&V) is
underway or planned for improving SIM, but most of the effort is directed toward high
risk, non-drinking water applications. Example applications include oil and natural gas
pipelines, nuclear power plants, large buildings, bridges, and aircraft. A significant
amount of this research is government-sponsored. Many of these SIM improvement
efforts involve applying recent advances in technology to the creation of better, cheaper,
and faster ways of acquiring and analyzing structural integrity data. The products, data,
and procedures from some of this R,D,T,&V are a relatively untapped source of
technology transfer opportunities for water main SIM improvements, but there is no
systematic effort to identify, prioritize, and capitalize on these opportunities by the
federal government, and in particular the EPA.
Acceleration of the SIM improvement process is important, since: (1) SIM capability
improvement is a difficult, uncertain, slow, tedious, and expensive process; and (2) a
substantial portion of the transmission and distribution system is projected to be
approaching or reaching the end of its service life. The need for decisions to implement
or delay replacement will be greatly increasing between now and approximately 2035,
when the annual replacement rate is projected to peak at about 2% (i.e., 16,000 to
20,000 miles of pipe replaced/year), which is more than four times the current
replacement rate. (U.S. EPA, 2002 b and c)
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Resources are limited, so it is important for the drinking water community, including the
federal government, to define and prioritize drinking water mains SIM capability
improvement needs, and cooperate and collaborate to complete the required R,D,T,&V
activities.
Scope of the white paper
Prevention of main breaks is emphasized over prevention of main leaks. The adverse
economic effects of main breaks (e.g., damages, disruption of business and traffic, and
emergency response costs) and potential for health effects (e.g., potential contaminant
intrusion or backflow due to pressure loss) appear to be more immediate and severe,
and more likely to be linked to a specific main break incident than for main leaks.
Although more water is probably lost from leaks than from main breaks, leaks are often
tolerated for a variety of reasons.
To the extent that main leaks can serve as a reliable indication of the location and
timing of future main breaks, the detection, location, and quantification of main leaks is
relevant to pre-failure detection, location, and prevention of main breaks. However,
detection of pipe leaks is not specifically addressed here, because it is covered in other
documents (e.g., O'Day et al., 1986; Makar and Chagnon, 1999; Smith et al., 2000;
Jackson et al., 1992; Tafuri, 2000; Hunaidi et al.,1999).
Although improvement of structural condition assessment (SCA) is closely related to
improvement of SIM, SCA is excluded, to the extent feasible, from the scope of this
white paper. SCA is the determination of the present and future fitness-for-service of
the pipe. It will be assumed that adequate SCA for at least the imminent failure case is,
or will become, feasible for some indicators and situations (e.g., corrosion pitting (Rajani
and Makar, 2000), severe wall thinning, cross section deflection, misalignment, or
bending). Inspection without effective condition assessment limits the value of the
inspection to identification of failures that are either existing or obviously imminent.
Condition assessment requires inspection data and is affected by inspection data
accuracy. Although SCA improvement is excluded from this white paper, research on
the topic is recommended to add value to current and future SIM capability.
Integration of SIM with hydraulic and water quality monitoring in the distribution system
is a desirable goal. Although this is a potential future research goal, it is beyond the
scope of this white paper.
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Section 2: Detailed Problem Statement
This section describes: (1) water main breaks and their causes and risks, (2) the
difficulties in inspection of buried water mains, and (3) the shortcomings of existing SIM
capability.
Description, causes, and risks of water main breaks
A water main break is the structural failure of the barrel or bell of the pipe. Types of
water main breaks include: (1) circumferential breaks; (2) longitudinal breaks; (3) holes
caused by either corrosion or pressure/blowout; (4) split bells, including bell failure from
sulphur compound joint materials; (5) sheared bells; and, (6) spiral cracks (O'Day et al.,
1986; Makar et al., 2001). Water main breaks typically produce a substantial loss of
pressure and flow at the point of the break and possibly elsewhere in the system, and
therefore tend to be readily detectable and require immediate attention. In contrast,
water main leaks often produce smaller, less easily detected, and less disruptive
changes in pressure and flow that may go undetected and/or uncorrected for some
time. The distinction between a large leak and a main break is often unclear.
Water main breaks are caused when and where the loading on the pipe exceeds the
pipe strength (i.e., ability to resist loading). Corrosion is a major cause of pipe strength
deterioration. There are multiple causes of corrosion. Corrosion can occur on either
the interior or exterior of the pipe. Manufacturing flaws can also contribute to pipe
strength deterioration. Numerous types of loading can contribute to weakening the pipe
or causing failure. Multiple factors may act together to cause failure (O'Day et al., 1986;
Makar et al., 2001). Table 1 provides a more extensive list of factors that contribute to
pipe failures.
The risk posed by a main break is the product of the consequences and the probability
of failure. Only low risk (i.e., low probability and consequences) and high risk (i.e., high
probability and consequences) situations will be discussed immediately below. High
risk main breaks are the predominant focus of the report. Intermediate risk situations
will require an appropriate blend of the high and low risk approaches for scheduling R3.
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Table 1.
Main Break Occurrence Factors
Chemical
Stressors
Internal & external corrosion caused by factors such as aggressive
water or soil, microbes, stray currents, oxygen gradients, &
bimetallic connections
Physical
Stressors
Damage during transport, unloading, storage, & installation
Traffic loads
Soil loads from differential settling caused by bedding washout from
water leakage, drought, expansive clays, & landslides
Point loads from projecting rocks, etc.
Internal, radial loads from water pressure fluctuations
Axial loads from seismic activity, soil movement, & water hammer
Thermal stress from temperature differences between water, pipe, &
soil; freezing/expansion of water; & soil frost loads
Damage by excavating equipment that causes or accelerates failure
Damage to external coatings or internal linings that enables
accelerated corrosion
Other
Factors
Aging (i.e., the accumulation of effects over time from external
chemical & physical Stressors & from equilibrium reactions within
the pipe (e.g., brittleness))
Pipe flaws arising from design, raw materials, manufacturing, or
installation errors
Prevention of low risk main breaks is not a high priority, since the benefits of
prevention are likely to be much less than the cost of prevention. The benefit of
preventing a low risk main break by SIM is small (i.e., the avoidance of the minor
adverse effects of an event that is unlikely to occur). The costs of preventing a
main break include the inspection cost (e.g., mobilization to/from an inspection
site; pipe preparation and return to service; data collection, storage,
transmission, analysis, and reporting); selection of the time, location of R3
actions; and implementing the R3 actions. Hence, the cost of preventing a low
risk main break is likely to exceed its benefit. Therefore, for low risk main breaks,
the focus tends to be on post-failure repair of the main until the frequency of
failure becomes so high that it is more economical to replace the pipe, rather
than continue to repair it. Procedures for calculating the optimum number of
breaks before replacements are available (e.g., O'Day et al., 1986).
For high risk mains the effects of even a single main break are serious, so
prevention becomes much more desirable. The ability to prioritize and schedule
R3 based on pipe condition can be especially valuable for systems that have a
substantial amount of high-consequence pipes that are approaching the ends of
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their service lives, but also have insufficient funds to address all the deteriorated
pipes at one time. In this situation, the order in which pipes are repaired,
rehabilitated, or replaced is very important, because the number of failures and
their adverse effects can be minimized by first addressing the pipes that are in
the worst condition and have the highest probability of failure. The development
of more effective and efficient inspection capabilities helps support "worst-
condition pipes first" scheduling of R3 and reduces the number of failures and
their adverse effects. Table 2 lists a number of potential high consequence main
situations.
Table 2. Example High Consequence Main Break Scenarios
Critical
Customers
Critical
Surroundings
Difficult
Response
Large population
Fire protection
Key industry/defense/government site
Hospital
Limited alternative supply
Industrial/commercial/residential
Highway/bridge/tunnel/railroad/subway/airport
Critical water main/sewer/communication
Energy pipeline/cable
Large main
Difficult terrain
Heavy traffic
Remote site
River crossing
Extreme temperatures
Water main breaks cause a range of adverse effects. Table 3 summarizes the types of
adverse effects that can be caused by main breaks. The first column lists adverse
effects that relate to public health and the environment, and many are relevant to EPA's
mission and programs. Of particular concern is the potential loss of pressure following a
main break, which can allow entry of contaminants, either at the break location or at
more distant locations by back-siphonage through cross-connections to contaminated
sources (American Water Works Association (AWWA), 2002). The second column in
Table 3 addresses adverse economic effects, which can have indirect or delayed, but
important, effects on distribution system structural integrity, and ultimately public health
and the environment. Adverse economic effects on utilities can affect drinking water
quality by causing deferrals of needed capital and maintenance expenditures, and by
further increasing the infrastructure funding gap. Appendix 1 lists 14 examples of some
recent (1996 to present) high consequence main breaks. Improved SIM capability
enables utilities to more effectively manage their water mains, which represent more
than 50% of the value of their assets.
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Table 3.
Types of Adverse Effects from Water Main Breaks
Health and Environment
Economic
Safety & Inconvenience
Public Health Problems
Waterborne disease outbreaks
Low pressure
Presumptive boil water notices
Noncompliance
Primary WQ standards
Loss of drinking/bathing water
Loss of water for sewage
Sewer overflows from flooding
DW Utility
Lost revenue
Response costs
System damages/repairs
Claims
Deferral of maintenance
Public Safety
Fire fighting water loss
Worker hazards
Traffic accidents
Flooding
Icing
Disruption
Electrical shock hazards
Other Water Quality Problems
Noncompliance
Secondary WQ standards
Resource Depletion
Water
Energy
Environmental Degradation
Chlorinated water discharged to
sensitive areas
Non-DW Utility
Property damage
Residential
Commercial
Industrial
Walk-in business losses
Production losses
Infrastructure
Damages/outages
Electric/gas/steam
Sewer
Communication
Road/tunnel/bridge
Train/subway/airport
Public Inconvenience
During main break
During remediation
Water main breaks can also cause serious adverse effects to public safety (e.g., loss of
firefighting water and pressure, flooding, and icing) and convenience. The third column
in Table 3 lists additional adverse effects of water main breaks on public safety and
convenience. Preventing these types of adverse effects is not part of EPA's clean and
safe water goals. However, since water main breaks are a common cause of both water
quality and public safety problems, there is some potential for research collaboration
between EPA and public safety research organizations.
Table 4 summarizes the data, identified in this study, that link water main breaks to
adverse effects on drinking water quality. A relatively small number of documented
incidents (17) were identified over a 25-year period. The most severe incident, which
occurred in 1989 in Cabool, Missouri, resulted in 4 deaths, 32 hospitalizations, and 243
illnesses (Craun and Calderon, 2001). The actual number of main break incidents that
adversely affected water quality certainly exceeds the number of documented incidents,
but no quantitative estimates of the ratio of documented to actual incidents were found or
developed. There are several reasons for the difference between the documented and
actual number of incidents. "There are many backflow incidents which occur that are not
reported" (AWWA, 1995). It is often difficult to link contaminant entry to a specific main
break incident, since the identity and entry point of the contaminant may not be known;
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the contamination event may be of limited duration and volume, and probably difficult to
track; the presence of the contaminants or harmful effects may not be immediately
detectable by the consumer (e.g., pathogens, carcinogens); and there may be multiple
possible sources. Also, when there is a main break, efforts may tend to focus on
responding to the main break and any problems associated with it, as opposed to
searching for potential backflow.
One study cited in Table 4 lends support to the hypothesis that the actual number of
drinking water quality incidents exceeds the documented number of incidents. A survey
of 70 systems found about 2100 pressure reduction incidents caused by main breaks in
a one-year period. Pressure reduction can, when there are unprotected cross-
connections to contaminated sources and the pressure reduction is of sufficient
magnitude, enable backflow of contaminants into the system. Some utilities issue boil
water notices for sectors affected by main breaks based on the assumption that the
potential for loss of pressure increases the possibility that contamination may enter the
system. Two other studies (American Water Works Association Research Foundation
(AwwaRF) projects (No. 436 (Kirmeyer et al., 2001)), and No. 2686 in progress) are
examining transient, reduced-pressure waves that are caused by water velocity changes
from the main break, or by emergency valve closures in response to the break. These
studies should provide data regarding the probability that these transient low-pressure
incidents are enabling contaminants to enter the distribution system through holes or
cracks in the pipe. Reduced-pressure transients and the resultant inflow may occur at a
considerable distance from the main break, valve closure, or other cause of the pressure
transient. Deteriorating wastewater collection systems are a potential source of
Table 4. Summary of Main Break Incidents Affecting Drinking Water Quality
Mechanism
Contaminant entry at or near
break site
Backflow of contaminants due
to pressure loss
Pressure reduction incidents
from main breaks
Description
E. Coli contamination from sewage overflows enters mains via breaks
and meter replacements - 4 deaths, 32 hospitalized, 232 illnesses;
Cabool, MO, 1989 (Craun and Calderon, 2001)
17 contamination backflow incidents listed as due to main breaks
(1969 to 1994) (AWWA, 1995)
Many backflow incidents not reported (AWWA, 1995)
"A survey of 70 systems reported 11,186 pressure reduction incidents
in the past year... 19.2 % were due to main breaks, and 16.2 % of
incidents were due to service line breaks (ABPA, 2000). Hills and other
elevations compound pressure loss effects caused by main breaks, fire
flows, and other events (ABPA, 2000)." (U.S. EPA, 2002a)
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Table 4. Continued
Potential for intrusion of
contaminants due to pressure
transients
AwwaRF evaluations of occurrence and duration of low pressure
transients
- Microbial contamination of trench water demonstrated
- Occurrence of low-pressure transients demonstrated
- Potential intrusion volumes calculated
- Risk assessment not complete
(Kirmeyer et al., 2001; AwwaRF No. 2686, in progress)
Boil water advisories due to
pressure loss caused by a
main break
Data collection not attempted for this project
Boil water notices due to
confirmed contamination after
main-break-caused pressure
loss
Data collection not attempted for this project
Acceleration or reversal of
flow, mobilizes sediment,
biofilm, and associated
chemical or biological
contaminants.
Mobilization of solids is known to occur, but data collection not
attempted for this project to determine extent of water quality effects
and associated health risks
contaminants that could be drawn into water mains during low pressure incidents. Main
breaks may also accelerate and/or reverse the flow rate, which can disturb sediment or
shear biofilm from the pipe wall, mobilizing not only the sediment and biofilm, but any
associated chemical or biological contaminants. A further effect of acceleration or
reversal of flow due to main breaks is water hammer, which may cause cracks or holes
at other points in the system, which could contribute to the occurrence of the two trench
water contamination scenarios described above.
Magnitude of the water main break problem
This section presents statistics indicative of the magnitude of the main break problem in
the United States. This section does not address the number of main breaks by risk
class, material, diameter, failure mode, or preventability by SIM devices.
A 1994 estimate placed the number of main breaks in the United States at 237,600/year
(Kirmeyer et al.,1994). This estimate was based on an estimated total length of water
mains in the United States of 880,000 miles (excluding service lines) and a rate of 27
main breaks/100 miles/year. Variation is considerable between utilities. In one survey,
main break repair rates ranged from 7.6 to 38.1 main break repairs/100 miles/year for 4
utilities. Seasonal variations in main break rates also occur, and northern cities tend to
experience a substantial increase in main breaks during winter months. Data from
surveys of limited numbers of individual utilities indicate a mixture of increasing,
declining, and steady break rates. Based on the projected overall increase in the age of
10
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the U.S. distribution system piping and the substantial portion of it that is in either fair or
poor condition, it can be inferred that the main break rate should be increasing.
Approximately 29% of the United States' drinking water distribution system pipe was
estimated in 1992 to be in fair (26%) or poor (3%) condition (Kirmeyer et al., 1994). How
fast the 26% in the "fair" category will be joining the "poor" category is unclear. The pipe
replacement rate of about 0.5% (Kirmeyer et al., 1994), if continued, will result in an
average service life of 200 years, which is well beyond the typical design service lives of
50 to 100 years. The wastewater infrastructure also has deterioration problems, which
will increase the probability of water main and sewer breaks occurring in close proximity.
On the positive side, expansion of expenditures from the Drinking Water State Revolving
Fund (DWSRF) and utilities for infrastructure rehabilitation and replacement, increased
emphasis on efficient asset management, and more extensive use of pipe rehabilitation
should help to reduce failure rates for the systems affected. Several new factors may
affect main break rates in the future, such as the long-term structural integrity of pipe laid
by new installation techniques and of pipe rehabilitated by new methods. There are also
significant differences in pipe material (e.g., a tendency to use more polymer pipe),
coating, and lining materials that may affect (positively or negatively) long-term main
break rates. Even changes in disinfectants may have some effect (positive or negative)
on long-term structural integrity.
The need for improved SIM technology
Numerous SIM methods have been developed over the years. Table 5 places SIM
technologies into 12 groups and lists some their key weaknesses. SIM technologies are
described in more detail in other documents (e.g., Dingus, et al., 2002; Tafuri et al.,
2001; Stone etal., 2002; Cromwell et al., 2001; O'Dayetal., 1986; Debetal., 2002;
Lawrence, 2001; Fennell and Lawrence, 2000; Jackson et al., 1992; Hunaidi et al., 1999;
Rajani et al., 2000; Smith et al., 2000; Bickerstaff et al., 2002).
Current SIM approaches have serious limitations for water mains, especially if buried.
Hence, structural integrity failures are often addressed by reactive maintenance, which is
initiated after detection of an indicator of a structural failure (e.g., water spout; loss of
pressure, volume or quality). Reactive maintenance must often be done under
unfavorable weather, lighting, traffic, and/or schedule conditions. Repairs done under
adverse conditions (e.g., water filled trench) may allow contaminated water to enter the
pipe. In spite of the potential adverse health and economic consequences of reactive
maintenance following failures, there may not be a technically or economically suitable
alternative at the present time. Even where preventive maintenance, rehabilitation, and
replacement programs are in place, their efficiency and effectiveness are hampered by
the difficulty of accessing the system and efficiently inspecting it.
11
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Table 5. Performance Weaknesses of Structural Integrity Monitoring Approaches
No.
1
2
3
4
5
6
7
8
9
10
11
12
Key
1
2
3
4
5
SIM Approach
React (respond, repair/replace/rehab, cleanup) after failure
Monitor water quality (e.g., taste, odor, color, residual
chlorine, microorganisms, composition, outbreaks)
Excavate & inspect outer pipe surface
Excavate & remove pipe samples for evaluation
Insert/remove & monitor coupons of pipe materials
Monitor hydraulic parameters (pressure, flow, roughness)
Flaw detection & location by temporary, immobile sensors
(e.g., acoustic emissions for leaks or PCCP wire breaks)
Leak detection & location by external, remote sensing
(e.g., aerial or satellite) surveillance
Intrusive, intermittent, close-range inspection methods
(e.g., pigs with physical, optical, acoustic, ultrasonic, eddy
current, or magnetic flux leakage measurement assemblies)
Cathodic protection
Statistical evaluation of pipe characteristics, failure histories,
maintenance records, and environmental conditions to
generate repair/replace priorities
Establish and monitor sensing layer (e.g., instrumented
cathodic protection, electrically conductive composite pipe)
Weaknesses (see key below the table)
1
Y
Y
N
?
?
Y
Y
Y
N
N
Y
N
2
N
Y
N
?
?
Y
N
N
N
N
?
N
3
?
?
Y
Y
?
?
Y
N
Y
N
N
?
4
N
N
N
Y
Y
N
N
N
Y
N
N
N
5
N
Y
Y
Y
Y
?
Y
Y
Y
N
Y
N
6
N
Y
Y
Y
Y
?
Y
N
Y
Y
N
?
7
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
8
Y
?
N
?
?
?
?
?
?
N
?
?
9
?
?
?
?
?
?
?
Y
?
N
?
?
10
N
N
N
N
N
N
N
N
N
N
N
Y
N = Not a weakness; Y = Yes, it is a weakness; ? = Uncertain whether it is a weakness or it depends on the situation.
Only applicable to post-leak or break
detection, not prevention
Detects problem but does not efficiently
locate it
Labor intensive & slow
Requires intrusion into system
Incomplete temporal coverage - non-
continuous inspection may miss short-
term deterioration events (e.g., wire
breaks)
6
7
8
9
10
Incomplete spatial coverage - not applicable to all sections or
components of system, configurations, or ambient conditions
Incomplete failure mode coverage -not applicable to all failure mode
indicators (e.g., wall thinning, cracking, holes, leaks, & corrosion)
Inaccurate or unreliable determination of current structural condition
Inability to utilize the data to forecast residual service life
Still in development
12
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Section 3: Public Benefits from SIM Improvements
Improving SIM capability through R,D,T,&V is a proactive, cooperative, flexible
approach to accomplishing a number of EPA's short-term and long-term drinking water
protection goals. Reducing main breaks supports the Safe Drinking Water Act's goals
of protecting public health and drinking water quality. Reducing main breaks, optimizing
maintenance planning, extending infrastructure service lives, and reducing water
leakage supports EPA goals of reducing the infrastructure funding gap and improving
utilities' infrastructure management capability. Table 6 links the benefits of SIM
capability improvement to the associated EPA goal areas.
A rigorous determination of the economic benefits from main break prevention was not
within the scope of this white paper. However, it is a relevant question, and so a
conceptual estimate of the potential economic benefits from main break prevention was
generated as a starting point for further consideration. Based on the assumptions
shown in Table 7, it was estimated that $2.4 billion in losses could occur annually from
high consequence main breaks. If 20% of these high consequence main breaks could
be prevented, then $480 million/yr in losses could be prevented. Again, based on the
assumptions in Table 7, an acceptable inspection cost rate was estimated at
$54,000/mi/yr (approximately $10/ft/yr).
A rigorous determination of the number of each type of main break that could be
prevented was not attempted. However, as was done for economic benefits, a
conceptual estimate was generated as a basis for further discussion. Each of the
approximately 240,000 water main breaks that occur in the U.S. each year has some
potential for causing adverse health, water quality, economic or other effects. Not all of
these main breaks are preventable for a variety of technical, risk, and economic
reasons, and the majority will probably not cause major adverse effects. However, if,
for example, 10% of main breaks can be prevented through improved SIM, then this will
reduce main breaks by about 24,000/yr, which is a significant number, even if it doesn't
completely eliminate the problem. More important than simply reducing the number of
main breaks is reducing the risk they pose. If classes of high risk main breaks are
focused upon and are successfully prevented, then the overall risk from main breaks
could be substantially reduced by preventing a relatively small fraction of main breaks.
13
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Table 6. Functional & Program Benefits of Effective & Affordable Inspection
FUNCTIONAL BENEFITS OF
EFFECTIVE AND AFFORDABLE
INSPECTION
OPTIMIZE ASSET
MANAGEMENT
- Optimize inspection frequencies
- Optimize repair, rehab, and
replacement scheduling
- Optimize service life
REDUCE MAIN BREAKS
- Reduce contaminant backflow
via cross connections
- Reduce intrusion from break-
induced pressure transients
- Reduce contaminant entry
at/near main break locations
- Reduce water loss
- Reduce damage costs
- Reduce response costs
REDUCE LEAKS
- Reduce water loss
- Reduce failure-inducing
conditions at pipe exterior
PROGRAM BENEFITS
Drinking Water Quality
Protection
Short-term
D
D
D
D
D
D
Long-term
D
D
D
D
D
D
D
D
D
D
D
D
Infrastructure
Funding Gap
Reduction
D
D
D
D
D
D
D
D
D
D
Water
Conservation
D
D
D
D
D
D
D
=the functional benefit cited in row heading benefits the program cited in column heading
14
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Table 7. A Conceptual Estimate of Economic Benefits & Acceptable Costs of Main Break
Prevention
Estimate of potential economic benefits
Length of installed DW mains in the U.S.
Number of main breaks(NMB) each year in the U.S.
Fraction (F1) of NMB that are in high consequence category
Number of high consequence main breaks/year (NHCMB)=F1 "NMB
Average total extra* cost(C) of a high consequence main break
* i.e., Total cost above normal main R3
Total Annual Cost of High Consequence MB (CHCMB ) = NMB *F1 "C
Fraction (F2) of NHCMB that are prevented by improved SIM
Number of prevented high consequence (NP.HCMB) = NHCMB *F2
Total Annual Benefit of Inspection (BINSP)=NHCMBF1 «F2 *C
Value
880,000
240,000
0.01
2400
1,000,000
2.400e+09
0.2
480
4.806+08
Units
Miles
Breaks/Yr
None
Breaks/Yr
$
$/Yr
None
Breaks/Yr
$/Yr
Estimate of Acceptable Cost of Inspection for High Risk Mains
Average total extra cost of a high consequence main break (C)
Average probability of HC main break (PHCMB) is same as average break from
(Kirmeyer, 1994)~
Annual extra risk from HC main break (C *PHCMB)
Annual extra risk from HC main break = Breakeven inspection cost = Cb
Acceptable benefit/cost ratio (R)
Acceptable inspection cost/mi/yr for HC main = (C^/R)
Value
1,000,000
0.27
270,000
270,000
5
54,000
Units
$/HC break
HC breaks/ mi/yr
$/mi/yr
$/mi/yr
None
$/mi/yr
Assumptions
Improved SIM can also, perhaps substantially, reduce premature R3. If the general
condition of U.S. drinking water mains deteriorates due to the pipe replacement rate
lagging behind the deterioration rate, there will be an increased need for efficient R3
decision-making. More efficient R3 decision-making is supported by accurate and
economical pipe condition data. For example, premature abandonment of relatively
new prestressed concrete cylinder pipe (PCCP) pipelines has been prevented by the
use of new SIM technologies that enable localized, accelerated deterioration of pre-
stressing wires to be detected, located, and repaired during scheduled maintenance.
Without this capability main breaks would have caused random, frequent, and serious
outages that would have made the pipeline too unreliable, hazardous, and costly to
continue to operate. As the U.S. distribution system ages and the need to allocate R3
15
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resources becomes more apparent, there will be an increasing demand for SIM data to
support accurate condition assessment and R3 scheduling.
Looking a bit further into the future, SIM capability improvements now may be laying the
groundwork for a revolution in pipe condition assessment models and maintenance
practices. Advanced SIM that enables intensive, long-term monitoring of pipeline
structural parameters will enable correlations to be sought that will improve applicability
and accuracy of service-life models. Advanced SIM that enables frequent and detailed
updates of the baseline condition of the pipe should substantially improve the accuracy
of service-life predictions by reducing the uncertainty about the actual condition of the
pipe at the time the remaining-service-life calculations are made. Advanced SIM
technologies that support forecasting of time, location, and modes of failure with greater
accuracy will encourage development and implementation of maintenance practices
that counteract the early stages of deterioration. This will prevent or delay failures and
extend the service life of the pipe network. For example, if coating damage can be
promptly and affordably detected and located, this may foster research and
development into procedures and equipment to quickly and efficiently repair the
problem to prevent more extensive and costly damage to larger areas of pipe, the
system, and surroundings. Another major future benefit of improved SIM capability
could be early warning about entire classes of pipes/liners/coatings that are
deteriorating faster (or slower) than expected. Several years worth of decisions -
perhaps at utilities across the country - regarding pipe selection, installation,
rehabilitation, or manufacturing practices could be favorably modified as a result of early
warning from SIM data. Multiple changes are occurring whose effects on short-term
and long-term structural integrity in drinking water systems bear watching via improved
SIM, if suitably effective and affordable methods can be devised. These changes
include new pipe materials, installation methods, disinfectants, and rehabilitation
methods.
16
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Section 4: The Challenges of Improving SIM Capability
In previous sections the shortcomings of existing water main SIM approaches and the
benefits of improving SIM capability were described. This section addresses the
challenges of improving SIM capability from two perspectives. The first perspective
views SIM capability improvement as the process of upgrading the performance and/or
cost of the technical sub-tasks that comprise SIM. The second perspective views SIM
capability improvement as the process of increasing the value (i.e., the benefits minus
the costs) of SIM to the utility. Subsequent sections will describe new technologies that
offer promise for addressing the obstacles to improving SIM performance and cost.
The technical challenge
Meeting the technical challenge of improving SIM capability consists of substantially
improving the effectiveness, speed, reliability, or affordability of one or more of the SIM
sub-tasks listed in Table 8 for one or more high risk water main situations. A detailed
discussion of the challenges involved in improving performance in each of the listed
sub-tasks for each high risk main scenario is beyond the scope of the white paper.
Inspection of Table 8 reveals that a substantial number of SIM sub-tasks that can
potentially be improved, and that a variety of disciplines are required to cause these
improvements.
Identifying and measuring pipe flaw parameter(s) with suitable frequency, sensitivity,
precision, and accuracy to determine present condition and deterioration rate are
difficult challenges. Pipe flaw parameters may include, for example, the location and
characteristics (e.g., number, dimensions, magnitude, and location) of leaks, wall
thickness, corrosion pits, cracks, pipe cross-section shape, strain, alignment, acoustic
and ultrasonic emissions, electrical resistance, electromagnetic field strength,
temperature, and various loadings. Pipe flaw parameters must correlate with pipe
strength to be useful. Data must exist or be collected to determine the correlation
between critical flaw levels and the probability of failure. The flaws must be measurable
with sufficient precision to enable differentiation between critical and non-critical flaws.
The fragmentation of application scenarios and research needs is another challenge.
Some important examples of fragmentation are listed in Table 9.
17
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Table 8.
SIM Generic Sub-task List
D Develop Inspection Plan (What, When, Why, How, Where)
D Specify Critical Flaws or Critical Indicators
D Prepare Pipe for Inspection
D Position the Sensor(s)
D Generate Probe Signal (Active Systems)
D Receive and Store Return Signals and Associated Data
D Partial On-site Analysis
D Transmit Inspection Data to Final Analysis Location
D Analyze Data
D Determine Present Structural Condition of the Pipe
D Determine Deterioration Rate
D Return Pipe to Service
D Repeat above Actions until Inspection Cycle Is Complete
D Provide Power for Preceding Actions
D Maintain the Inspection System Hardware and Software
There are numerous pipe scenarios, and the capability to estimate time and location of
failure for one scenario may not be applicable to other pipe scenarios. Multiple SIM
approaches are required to address all pipe scenarios, and not all can be developed for
and supported by utilities. For a particular pipe scenario (i.e., pipe age/condition/
dimensions/material/lining/coating/joints/connections/valves/bedding/external
loading/internal loading) there may be a few or many contributing factors that determine
when and where a main break will occur. Table 1 lists a number of the factors that may
contribute to occurrence of main breaks. Pipe failure scenarios amenable to prediction
and prevention via SIM probably need to be moderately simple, or at least need to
produce reliable indicators of the onset of failure. A pipe failure that occurs due to
multiple and varying causes is likely to be much more unpredictable and may require
intensive monitoring (i.e., spatial, temporal, and failure modes) that may be technically
and economically infeasible. Another challenge is to determine whether inspection-
related technology innovations can effectively and affordably collect useful data for
moderate to high risk main break scenarios.
18
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Table 9. Examples of Problem Fragmentation
Category
Risk
Pipe material
Failure mode
Pipe diameter
Accessibility
Installation status
Network
configurations
Size
Surroundings
Inspection
approaches
Research strategies
Examples
High vs. low consequences Utility vs. customer vs. community
Health vs. safety vs. economic Past vs. present vs. future
Metal (Cl, Dl, S); Concrete (AC, PCCP, Other); Polymer (PVC, HOPE)
Lining (Cement mortar, epoxy, polymer pipe); Coating (PE, other)
Corrosion (internal, external, type); loading (seismic, frost, water-pipe
temperature gradient, joint loads, surge, beam, point, traffic, combination)
Small diameter - higher probability, lower consequences; Large diameter -
lower probability, higher consequences
Piggable vs. non-piggable vs. man-entry
Past, present, future
Transmission vs. distribution - materials, diameters, number of connections
Large vs. medium vs. small system, budget
Ultra-urban vs. urban vs. rural
Inspection parameters & frequency; sensor type & density; data analysis
Incremental improvements to performance & cost of various types of existing
technology vs. "leapfrog" technologies that are novel, high-benefit, & high risk.
The variables cited above can pose difficulties for transferring inspection technologies
from well-established, high-risk industries. For example: "A wide range of in-line
nondestructive evaluation (NDE) methods are used in the oil and gas pipeline industry.
Configurations of water distribution piping different from those of oil and gas piping
present challenges to extending the use of in-line NDE methods from the oil and gas
industry to water pipelines. The inner surface of a water pipe is strongly irregular as a
result of scaling, pitting, graphitization, or tuberculation. Aggressive cleaning to provide
a clean, smooth inner surface is required for maximum effectiveness with most in-line
NDE methods. Oil and gas pipelines typically have long uninterrupted runs of pipe,
whereas water piping networks have many bends and connections. These
appurtenances produce signals that increase the difficulty of using in-line NDE methods
in a water distribution network. Steel pipe, widely used in oil pipelines, is a uniform
alloy, whereas Cl (cast iron) and Dl (ductile iron), common in water pipe networks, are
heterogeneous materials. Concrete pipe is both heterogeneous and does not conduct
electricity. Both heterogeneity and insulating properties of a pipe wall increase difficulty
of applying in-line NDE." (Smith et al., 2000).
19
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The process of taking a SIM technology improvement from invention through successful
commercialization is challenging because it is technically difficult, tedious, iterative,
risky, and expensive.
The value challenge
A successful SIM technology is one that adds value (V) over its lifetime to utility
operations. The general challenges, as well as some of the options for achieving
positive value from inspection, are discussed below with reference to equations and
insights provided in or derived from "Economic assessment of inspection - the
inspection value method" (Wall and Wedgwood, 1998). The equations below concisely
identify the factors and interactions affecting inspection value, and the general options
for inspection improvement.
The value of inspection is the difference between the benefits (B) and the costs (C) of
inspection. Ideally, a SIM technology will be selected when its value exceeds a critical
minimum value (Vc) that is greater than zero. Vc is affected by a number of factors:
benefits, costs, and value of competing SIM approaches.
V = B-C>Vc>0 (Eq. 1)
B is the reduction of the risk of failure, which can be expressed as the product of
reduction in the probability of failure ( P) times the consequences of failure (CF), in
monetary terms if possible. Hence,
V = P -CF - C (Eq. 2)
Finally, the term P is itself the product of two terms. "For a single mode of failure of a
single component, a suitable inspection would reduce the risk by the factor's POD, the
probability of detection, and F, the coverage." (Wall and Wedgwood, 1998).
V = POD -F -CF-C (Eq. 3)
From Equation 1 it can be seen that improving V depends not just on increasing B, but
also on controlling C, so that any gains in B are not completely eroded or surpassed by
increases in C.
Equation 2 shows the importance of CF on V. The value of CF is the maximum
possible value of inspection, and CF is independent of the inspection method. A
fundamental challenge of SIM for water mains is the low value and safety of water
compared to gas, oil, or other hazardous liquids and gases. Determining CF requires
an understanding, the more quantitative the better, of the effects of failure on the utility,
its customers, and the surroundings. As CF increases, the potential benefits from
inspection increase. Strategies for increasing CF to help achieve V>Vc include: (1)
focus inspection resources on high CF situations where there is a reasonable probability
of detecting critical flaws; (2) place a high priority on identifying and closely examining
high CF situations when setting SIM research priorities; (3) when appropriate, use total
and life cycle cost estimation methods, rather than just repair costs, to estimate CF; and
20
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(4) factor relevant cost trends (e.g., water, property values, infrastructure values, labor,
demographics, energy) into CF estimates.
Equation 2 also shows the importance of P, the reduction in the probability of failure,
on the magnitude of B, and hence V. The magnitude of P, which ranges from 0 to 1,
determines the fraction of CF that contributes to B. The magnitude of P is strongly
influenced by the performance of the SIM technology. For a given pipe material-critical
flaw combination, as an inspection method improves, the number of critical flaws
discovered and failures prevented increases. As the magnitude of P increases, so
does B. This is a concise conceptual justification for improving inspection technology.
P, and hence B and V, are also influenced by the condition of the pipe. For example,
if the pipe is in poor condition (i.e., high probability of failure), then there is a higher
probability of detecting critical flaws and thus achieving a large P than if the pipe had
no or very few flaws. The strategies for increasing the magnitude of P are to match
the SIM technology to pipe conditions to which it is well suited, and to improve the
performance of SIM technology as described in more detail in later parts of this section
and following sections.
Although in Equation 2 the term P «CF, the benefit of inspection, is typically
considered to be the product of two negatives (i.e., a decrease in the probability of
failure times a monetized loss due to the failure), one can also think of the benefit of
inspection in terms of the product of an increase in a positive consequence. For
example, an increase in the probability of successfully justifying a needed rate increase
or obtaining a loan. Also, the failure need not necessarily be a main break and its
consequences. The failure could also be a decision-making error that leads to
premature R3.
POD is the ratio of critical flaws detected and those actually present in a representative
pipe sample. From Equations 2 and 3, POD has an important influence on P, and
hence on B and V. POD is a function of the behavior of the pipe-loading system, the
level of understanding of the pipe-loading system, and inspection device performance.
The ability to specify critical flaws requires that the pipe-loading system behaves so that
pipe deterioration produces flaws or indicators (e.g., general wall thinning, pits, cracks,
bending, change in shape, or acoustic emissions) that are known to correlate to the loss
of strength of the pipe and also to the imminent approach of failure, i.e., when loading
exceeds strength. The pipe-loading system behavior must be sufficiently understood so
that the characteristics of critical flaws (or critical flaw indicators) can be defined. The
sensitivity, accuracy, precision, and reliability of the SIM technology influences POD of
critical flaws during inspection. The simplest situation for successful inspection is when
a predominant, well-characterized type of critical flaw exists, and the inspection method
is very effective and reliable in detecting and locating the critical flaw. Strategies for
improving POD include: (1) improving and/or verifying the sensitivity, precision, and
accuracy of sensing devices for detection and characterization of various types of
critical flaws and indicators; (2) increasing the spatial and temporal density of sensors
21
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as they become smaller, less costly, more efficient, and more durable, and (3)
characterizing material properties, deterioration, flaw initiation and propagation, and
failure conditions for inadequately understood pipe-loading systems.
Coverage (F) is defined (Wall and Wedgwood, 1998) for a particular inspection as the
fraction of the pipe that is actually inspected. From Equations 2 and 3, F has an
important influence on P, and hence B and V. Strategies for improving F include
developing SIM technologies that can more quickly, efficiently, and effectively detect
and characterize critical flaws in a greater range of pipe diameters, materials, and
coatings that comprise high-risk drinking water mains. Total coverage maximizes the
probability of detecting critical flaws. However, the level of coverage that optimizes the
value of inspection may be much less than 100% because of the additional cost and
reduced incremental benefits as inspection coverage approaches 100%. For example,
Wall and Wedgwood (1998) cite an example in which optimal coverage was estimated
at 10%. The definition of coverage can also be broadened to include not only spatial
coverage, but also temporal coverage. Temporal coverage is the frequency with which
the structural parameter is measured (e.g., continuous monitoring, inspection at regular
intervals, or no inspection and responding after failure). Continuous monitoring is
important if the monitored parameter is a short-term event (e.g., the acoustic emission
from a wire break in a prestressed concrete cylinder pipe). Sufficiently frequent
inspection is necessary if deterioration rates are to be determined and used for
optimizing inspection and maintenance scheduling.
As indicated in Equation 1, C must be effectively controlled if SIM capability
improvements are to provide added value for utilities. There are many potential
opportunities for reducing inspection costs through inspection technology
improvements. One approach is to reduce the labor hours for inspection. This may
include reducing the time required to: prepare the pipe/liner/coating for the inspection
device; move the inspection device within range of the pipe flaw; collect and store the
structural integrity data; return the pipeline to service; analyze the data; and prepare the
report. Another approach to cost reduction is to improve reliability, since false positives
incur unnecessary repair, rehabilitation, or replacement costs. Improving durability of
the inspection system can also reduce costs. Sharing inspection costs within and
between utilities may also be an option in some cases. For example, some supervisory
control and data acquisition (SCADA) system costs for SIM may be shared with
hydraulic and water quality monitoring activities. Higher initial costs for more effective
and efficient data collection systems must be balanced against the potential for longer-
term benefits and cost reductions.
22
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Section 5: Opportunities for SIM Capability Improvement
Overview
A number of important trends and circumstances make this decade (2004-2014) not
only a critical, but also an opportunity-filled time to accelerate the improvement and
verification of SIM technology and procedures for drinking water conveyance and
storage systems. The feasibility of improving SIM capability for drinking water mains by
adapting new technologies has already been demonstrated for a number of situations.
Multiple additional needs for SIM improvement have been identified. Advances in
relevant science and technology areas, such as sensors, communications, computing,
and materials science are occurring that can significantly improve the quantity, quality,
timeliness and cost of structural parameter data for determining structural strength,
deterioration rates, loading, and approach to failure conditions for various structures.
Improvement of SIM technology is typically a lengthy, difficult, costly, and uncertain
process. Nonetheless, for various high-risk, non-drinking water applications, multiple
SIM improvement attempts are underway. Products (e.g., concepts, prototypes, data,
and demonstrations) from these attempts can provide opportunities to economically
accelerate the improvement of SIM capability for water mains. Projects are also
underway to improve SIM for drinking water mains, but numerous unmet needs still
exist. Promising opportunities for productive intra-EPA, interagency, and federal-private
collaboration exist. For example, the federal government already possesses substantial
research, development, testing, and verification capability relevant to non-destructive
evaluation (NDE). EPA can help focus existing Federal capabilities on improvement of
drinking water structural integrity monitoring research needs, as the U.S. Department of
Energy (DOE) and the U.S. Department of Transportation (DOT) have done for energy
pipeline SIM capability improvements. While collaboration will help accelerate and
expand the number of options investigated, there is also a need for ranking, in
cooperation with the user community and others, the value of potential SIM
improvements. This ranking effort will help focus future collaboration efforts.
Opportunities to improve SIM capability
Although improving SIM technology for underground pipelines is difficult, it is possible.
This has recently been effectively demonstrated by several technologies for limited sets
of drinking water main conditions. For example, Table 10 lists six technologies (i.e.,
acoustic emission, electromagnetic, impact echo, remote field eddy current (RFEC),
seismic, and ultrasonic) and describes the pipe materials and defect types to which they
are applicable. Another example of SIM technology improvement is the development
23
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Table 10. Summary of NDE-method Issues that Affect Technique Selection for
Various Water Pipe Materials (Dingus et al., 2002)
Inspection
method
Acoustic emission
Electromagnetic
Impact echo
RFEC
(Remote Field
Eddy Current)
Seismic
Ultrasonic
Pipe material
Pretensioned or prestressed
concrete pipe
All metallic pipe
Concrete pipe containing
steel
All metallic pipe
All concrete pipe
All metallic pipe
Defect types
Breaks in reinforcing steel
Slippage of broken reinforcement
Concrete cracking
Cracks
Delaminations and cracks at
various concrete/mortar/steel
interfaces
Changes in metal mass,
graphitization
Wall thinning
Gouges
Large cracks
Reductions in concrete modulus
because of aging
Reductions in concrete
compression as a result of
breakage or slippage of
reinforcing steel
Detection of wall thinning
Notes
Pipe not removed from service
Hydrophones left in place for
several days to weeks
Commercial, off-the-shelf
availability
Detect environmental
conditions that are likely to
weaken pipe
Does not directly inspect pipe
Totally noninvasive
Requires dewatering and
human access to interior of
pipe
Can be done externally if
exterior access available
Commercial, off-the-shelf
availability
Pig travels through pipe via
water hydrants
May require cleaning before
inspection
Pig may dislodge material
from pipe wall, requiring
flushing
Requires dewatering and
human access to interior pipe
Not commercially available for
water pipe
Does not require dewatering of
pipes
Developed for inspecting oil or
gas pipelines systems are
long, inflexible, and expensive
of instrumented cathodic protection. Cathodic protection for electrically continuous
metallic pipes is not a new technique, and is required for gas and petroleum pipelines
(Lawrence, 2001). It basically involves sensing and maintaining an electrical potential
balance in the system that inhibits corrosion. Instrumented cathodic protection is an
improvement that enables the cathodic protection system itself to be monitored, which
prevents failures due to malfunctioning cathodic protection systems (e.g., Hock, et al.,
1994; Van Blaricum, 1998).
While improvements to SIM technology have occurred, numerous unmet SIM capability
improvement needs remain that will require research, development, testing, and
verification. As noted in a previous section, existing SIM technologies have many
known performance and cost deficiencies. Table 11 lists key SIM technology
24
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improvement research needs that were identified in several recent studies on water
main inspection technologies.
At least four SIM approaches for water mains appear to the author to have the potential
for significant improvement through the incorporation of better and more economical
technologies for sensor positioning, sensing, and data storage, transmission, and
analysis. These four SIM approaches are: mobile in-line inspection systems; mobile
non-intrusive inspection systems, continuous inspection devices, and intelligent
systems. These SIM approaches are described immediately below, followed by Table
12, which lists the types of improvements that would enhance their performance and/or
affordability.
Mobile In-line Inspection (MILI) systems - These systems require the
measuring device to be physically inserted into, moved through, and removed
from the pipe. The MILI sensors are usually in close contact with the pipe wall
and measure structural parameters over short distances. MILI systems collect
structural data for a given area or volume of the pipe for the short interval during
each inspection cycle that the sensor is in measuring range of the parameter(s)
of interest. Examples of MILI device output are: (1) visual images of the inner
surface indexed to pipe location, (2) continuous or discrete wall thickness profiles
indexed to pipe location, and (3) void spaces outside the pipe indexed to pipe
location. The pipe may have to be drained and/or cleaned to enable MILI devices
can be employed. For small diameter pipes MILI devices may be operated either
automatically or remotely. For large diameter pipes there is the additional option
of direct inspection or MILI device operation by a person.
Mobile Non-Intrusive Inspection (MNII) systems - These systems differ from
MILI systems because (1) the detector is not placed inside the pipe. MNII
systems that can examine a substantial length of pipe from a single location,
preferably without excavation, offer the promise of substantially reducing the
time, cost, and disruption involved in pinpointing pipe that should receive detailed
scrutiny. Examples include: (1) Lamb wave devices that transmit and receive
ultrasonic waves for moderate distances (e.g., 100 ft) along the pipe wall,
25
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Table 11. Selected SIM Research Needs for Drinking Water Mains Ref-*
Improved Problem Characterization - Further study of failure mechanisms in water main pipe J,
materials should be conducted. This is necessary to ensure that developing NOT technologies are M&K
directed at detecting all defects that are problematic for water mains.
Improvement of Sensing and Reporting - General
"The recent emergence of some water utility NDE (nondestructive evaluation) hardware is encouraging D
for the industry, but its application is limited by pipe size, types of materials, and similar issues. These
limits typically leave the water utility with more than 90 percent of its system being ineligible for NDE
inspection."
"Sensor research is needed in the following areas: development of more accurate and precise sensors;
development of sensors that can be calibrated remotely; and analysis of the payback time for
investments in implementing remote, real-time monitoring using data logging devices and remote
telemetry..."
Metallic Pipes (Cast and Ductile Irons, Steel, and Mortar and Polymer Lined Metals)
"... water utility managers are most concerned about... unlined cast iron and steel piping. Methods for
testing and assessing the condition and serviceability of such pipes are expensive and time-consuming,
and disruptive to customers. Better approaches to assessment, preferably nondestructive methods for
testing, are needed to help utilities define the condition, estimate the future pipe life, and focus their
rehabilitation and replacement needs where they are needed most."
"Off-the-shelf methods are readily available... Equipment and services are available off the shelf for D
small-diameter (up to 24 in.) piping. There are, however, areas of research that would increase the
confidence that utilities have in these inspections while providing more benefit than currently available
from in-service inspections."
"Further research needs to be done to develop both ultrasonic inspection and the remote field effect as
tools for measuring three-dimensional sizes of corrosion pits."
Concrete Pipes
"To make AE systems (for monitoring wire breaks in PCCP) easier for water utilities to use, it would be D
best to be able to insert hydrophones through blow-off valves. To accomplish this, manufacturers need
to reduce the size of hydrophones. This would help the utilities by causing less interruption to the
pipeline and the customers."
"Systems for IE (impact-echo), sonic, and AE (acoustic emissions) testing of buried concrete water pipes D
are commercially available, but ...need further development to correlate NDE results to reductions in
pipe integrity..."
"There has been essentially no work done on the inspection of A-C (Asbestos-Cement) pipes. ...The D
applicability of various concrete/cement/mortar NDE methods should be evaluated for ...in situ
inspection of A-C water pipes..."
* See end of Table for reference key; Table 11 is continued on next page
26
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Table 11. Continued
Polymer Pipes - "There has been no work done for NDE of polymeric water pipes (i.e., FRP, PE, PVC, and biaxially
oriented PVC types ...) Basic (r&d) should be performed to understand failure and defect types. Existing polymer
NDE methods should be combined with existing water pipe inspection pig equipment."
D
Improved Coverage by In-line Inspection Devices
"New pig designs that are specific to the water utility application are needed, and NDE technologies need to be
optimized to water pipe materials and their deterioration characteristics."
D
"Because of bends and elbows in water pipes, pig manufacturers need to create fully articulating systems that can get
around any corner. The most promising solution for this comes from NDE of boiler tubes that have multiple 180°
bends."
D
"Widespread use of piggable (i.e., fully opening) valves would greatly assist in allowing NDE (non-destructive
evaluation) tests. Most valves in water systems are not fully opening and do not allow a pig to pass... An impact
study could determine if the impacts of switching to fully opening valves would outweigh the benefits of NDE via pigs."
D
Strain Monitoring - Interest was expressed in SIM technology for excessive strain in the pipeline, since some
pipe failures occurred from pipes breaking due to bending caused by improper bedding or wash-out of bedding by
adjacent leaks.
M&J
D = Dingus etal., 2002 J = Jackson et al., 1992 K= Kirmeyer et al., 1992
M&J= Meegoda and Juliano, 2003 (draft) M&K = Makar and Kleiner, 2000
R = Rajani, et al., 2000 S = Smith et al., 2000
which enables 200 ft of pipe to be inspected from one location; (2) electric field
monitoring devices, which temporarily electrify the pipe, then detect electric field
changes at the ground surface that are indicative of pipe wall thinning and indicates
problem locations for detailed investigation; and, (3) aerial or satellite systems for
remote monitoring of surface conditions indicative of pipe deterioration or failure. Like
the MILI systems above, MNII systems provide a "snapshot" of the measured pipe
structural parameter(s) during each mobilization/inspection/demobilization cycle.
D Continuous inspection devices - These devices collect structural data
frequently, which improves the capability for detecting and tracking transient
deterioration indicators (e.g., acoustic emissions from cracking, leakage, or wire
breaks in prestressed concrete cylinder pipe). These devices can be intrusive
(i.e., require placement inside the pipe) or non-intrusive. These devices may be
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Table 12. Research Issues for Improving Four SIM Approaches
Performance Improvements
Improve probability of detection (POD)
* Increase parameter measurement sensitivity,
precision, accuracy, and speed
* Establish correlations between measurable
structural integrity indicators, load-bearing
capacity, deterioration rates, and failure
Improve Coverage (F)
* Temporal (sampling rate, duration, reliability)
* Spatial coverage (i.e., inspectable volume)
* Failure mode coverage (e.g., more flaw types,
sizes, alignments, and shapes)
* Pipe scenario coverage, e.g.,:
- pipe diameters, materials, thicknesses,
- pipe, liner, and/or coatings
- existing, replacement, rehabilitated, new
Launching and retrieval procedures
Improve data screening capability
Improve data transmission rates
Energy supply strategies & technologies
Cost improvements
Identify cost reduction targets for promising
advanced SIM system based on benefit-cost
analyses:
- life-cycle benefit/cost analyses
- total benefit/cost analyses
Reduce equipment, energy, operating &
maintenance costs
Remote, automatic, continuous-capable
operation
Mobile
In-Line
Inspection
D
D
D
D
D
D
D
D
D
D
D
D
Mobile,
Non-
Intrusive
Inspection
D
D
D
D
D
D
D
D
D
D
D
D
Continuous
Inspection
Devices
D
D
D
D
D
D
D
D
D
D
D
D
D
Intelligent
Systems
D
D
D
D
D
D
D
D
D
D
D
D
= the type of performance improvement in the row heading would benefit the corresponding class of SIM technology
= the type of performance improvement in the row heading would provide minimal benefit
28
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operated on a moderate to long-term basis (i.e., data collection for the inspected
area may occur for a day, week, month, or years). The defect to sensor distance
may be moderate to long. Cable-mounted hydrophones for acoustic emission
monitoring of wire breaks in prestressed concrete cylinder pipes (PCCP) is a
continuous inspection device.
Intelligent systems - These are permanent, comprehensive, and automated SIM
systems. The sensing and data storage/transmission/analysis capabilities are
built-in or retrofitted to the monitored portion of mains. The sensing capability is
selected and installed for the desired spatial, temporal, and failure mode
coverage. Examples include instrumented cathodic protection (ICP) (e.g.,
EUPECRMS, 2003), which monitors coating integrity over long distances for
cathodically protected pipelines or electrically conductive composite pipe (ECCP),
which is a prototype pipe with an embedded sensing layer (Meegoda and Juliano,
2003). Intelligent systems offer the potential for convenient, flexible, rapid,
comprehensive, non-disruptive inspection, if they can provide the quality of data
needed at an affordable price.
Table 13 lists several potentially preventable classes of main breaks. These types of
main breaks are potential target applications for SIM capability improvements.
Table 13. Examples of Potentially Preventable Types of Main Breaks
Cold weather main breaks whose occurrence in typical winter conditions can
be accurately forecast in the previous summer based on physical condition
data
Main breaks that are preceded by:
D Leaks that cause gradual bedding erosion and detectable excess strain
D Gradual soil movement and excess strain
D Increasing leak rate
D Gradual wall thinning
D Pitting
D Gradual wall deformation
D Mis-alignment
D Acoustic emissions from wire breaks, cracks, and leaks
D Coating failure that changes pipe electrical properties
D Cathodic protection partial or total failure
A number of projects have been undertaken in recent years to improve SIM capability
for drinking water mains and other purposes. These efforts should be built upon, not
duplicated. A substantial amount of infrastructure SIM research has been completed or
is underway for non-water infrastructure purposes that may be transferable to drinking
water distribution systems. Much of the other research and development has been
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directed toward other types of infrastructure (e.g., highways; bridges; tunnels;
petroleum, gas, chemical conveyance and storage; nuclear facilities; industrial piping) or
other applications (e.g., aviation, military, medical, automotive). Although these
applications are often for markedly different physical, chemical, pressure, temperature,
flow rate, and economic regimes, there should be some opportunities for transfer of
whole technologies, components, procedures, or data to water main applications.
Appendices 2.1 through 2.4 provide examples of research sponsored or conducted by
various organizations. Appendix 2.1 identifies ten recent or ongoing research efforts to
improve SIM technology for drinking water mains. Appendix 2.2 identifies 20 projects to
improve SIM capability or the use of SIM data for other types of pipeline applications.
Appendix 2.3 identifies non-pipeline research potentially relevant to drinking water SIM
applications. Appendix 2.4 is a list of smart/intelligent devices and systems that may be
applicable for various SIM applications.
There are many opportunities to interact with other federal agencies to accelerate the
evaluation and transfer of new technology for non-water pipeline applications to water
main SIM applications. Many Federal agencies are conducting SIM research or have
SIM research capability. However, their focus is usually not water pipeline applications,
but rather natural gas or hazardous chemical pipelines, other structures, or other
applications. Within EPA's Office of Research and Development (ORD), the National
Risk Management Research Laboratories' (NRMRL) Water Supply and Water
Resources Division (WSWRD) is responsible for distribution systems research. An
important role for WSWRD can be to educate other agencies about research needs and
priorities for water mains SIM research. EPA can also pursue collaboration on relevant
SIM projects where common ground exists between EPA's water-related SIM interests
and the other agencies' non-water SIM interests. EPA and the U.S. Department of
Defense (DOD) recently completed one interagency agreement on intelligent systems
for conveyance and storage systems. Opportunities for follow-up collaboration exist on
related projects and programs with DOD (e.g., smart materials and pipelines), DOE
(e.g., smart pipes, Intellipipe, and smart cities), the National Institute of Standards and
Technology (NIST) of the U.S. Department of Commerce (DOC) (e.g., smart layer
technologies), and DOT (e.g., intelligent pipelines for system reliability). The DOE's
Strategic Center for Natural Gas and Oil (SCNGO) and the DOT'S Office of Pipeline
Safety (OPS), have leading roles in promoting, funding, and performing short-term and
long-term SIM research, development, and demonstration projects for gas and
hazardous liquid pipelines. Between DOE and DOT there are over 40 active structural
integrity management technology projects. DOE's FY-03 budget for gas pipeline
integrity research is about $7 million. The National Science Foundation (NSF) is a
major supporter of research to improve sensors for civil and other systems. Other
federal agencies, such as DOD, NIST, and the National Aeronautics and Space
Administration (NASA), are also funding or performing multiple research projects that
are directly or indirectly applicable to improving structural integrity monitoring for
pipelines or other structures. The U.S. Bureau of Reclamation (USBR) previously
30
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supported research on a subsequently commercialized system for acoustic monitoring
of structural integrity of prestressing wires in prestressed concrete cylinder pipe
(PCCP). Seven examples of potential opportunities for SIM research collaboration
between EPA and other Federal Agency are identified in Appendix 3.
Complementing non-federal SIM technology research is another route for
ORD/NRMRL/WSWRD to accelerate the evaluation or development of improved water
main SIM technology. For example, current SIM technology performance is not close to
meeting drinking water user community needs, but consensus cost and performance
requirements for next-generation SIM technology have not been generated.
Inadequately defined cost and performance targets hinder the process of generating
interest and support for research to address the problem. ORD/NRMRL/WSWRD can
cooperate with the user community (e.g., AwwaRF, individual utilities) to define these
requirements by expert workshop and/or survey. The expectation is that once the target
performance and cost requirements are defined, it will become clear that: (1) achieving
next-generation SIM requirements will require research activity that covers the full range
of possibilities from fundamental research to verification of commercialized SIM
technologies, (2) private sector research resources alone cannot address all high
priority SIM approaches and pipe scenarios in an expeditious manner, and (3)
ORD/NRMRL/WSWRD and other federal research resources (e.g., personnel, facilities,
funding) can be invaluable for significantly accelerating the completion of SIM
improvement research. Based on the consensus cost and performance targets,
ORD/NRMRL/WSWRD can conduct complementary research and can also promote
within the federal research sector the inclusion of next-generation SIM needs in federal
research, development, demonstration or verification activities.
ORD/NRMRL/WSWRD can also work with non-federal organizations to investigate high-
benefit technologies that are typically too high-risk for user community and other non-
federal research programs. AwwaRF and specific utilities with active research
programs are key user community research organizations, and their research focuses
directly on water main applications. AwwaRF receives federal funding (e.g., $4.8 million
in FY-04 from EPA) for research, but only a portion of these funds are applied to
AwwaRF's infrastructure reliability (IR) program, and only a portion of the IR program
addresses SIM evaluation or improvement. Given the range of unmet research needs,
AwwaRF research support alone is insufficient to address SIM capability improvement.
Foreign research efforts in water main inspection and condition assessment, particularly
in Europe, Canada, and Australia offer collaboration opportunities. The Water
Environment Research Foundation (WERF) is another potential collaborator to the
extent that common ground can be found between SIM research needs for wastewater
mains and drinking water mains. AwwaRF, WERF, and EPA are currently cooperating
to issue an RFP (Protocols for Assessing Condition and Performance of Water and
Wastewater Assets, WERF Request for Proposals No. 03-CTS-20CO). Other relevant
research entities include the private sector (e.g., inspection device manufacturers and
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service providers), academia, private research organizations, non-profit research
organizations, and various partnerships and consortia that are producing and evaluating
components or systems potentially relevant to drinking water mains SIM.
EPA/ORD already has several programs that can potentially support SIM research for
water mains, but so far these programs have not been applied in a coordinated manner
for that purpose. The ORD programs that are the prime candidates for collaborative
efforts include ORD/NRMRL/WSWRD distribution system research program and the
Environmental Technology Verification (ETV) program; the National Center for
Environmental Research's (NCER) Small Business Innovation Research (SBIR)
program; the National Homeland Security Research Center (NHSRC), and the Office of
Science Policy's Federal Laboratory Consortium (FLC) project. Table 14 summarizes
the capabilities of these programs with regard to SIM improvement research. If
performance and cost improvement targets are defined for next-generation SIM
technologies, then this will provide a strong basis for increased intra-ORD collaboration
to help meet critical targets.
Table 14. Opportunities for Intra-EPA/ORD Research Collaboration
EPA/ORD Organization
NRMRLA/VSWRD
NRMRLyETV
NHSRC
NCER/SBIR
OSP/FLC
SIM Collaboration Opportunities
The NRMRL/WSWRD research program has the following SIM research potential:
- in-house, extramural contract, & interagency research program
- a pipeline test apparatus (2" to 12", 500 to 1000-ft, buried, steel) in Edison, NJ
- water quality monitoring, modeling, and control expertise
- distribution system simulator in Cincinnati, OH
- a project with AwwaRF to define next-generation SIM performance and cost targets
- potential for field-scale, controlled condition tests of leak detection devices, smart
pigs, and other condition assessment tools
The ETV program verifies performance claims for commercially available technology;
water infrastructure monitoring technology could potentially be within scope;
verifications could potentially utilize NRMRL/WSWRD test facilities.
NHSRC is a potential collaborator with NRMRL for research to address SIM needs
that overlap water security needs. Potential overlaps include: 3rd party detection to
prevent construction strikes and 3rd party detection to protect against terrorist
intrusion; surveillance systems; sensors; data transmission, storage, & analysis; and
post-failure/disaster inspection & assessment methods.
SBIR involves prototype development and evaluation, and offers opportunities to
focus small business research on SIM research for water mains.
OSP represents EPA on FLC. The FLC mission is - "To promote and facilitate the
rapid movement of federal laboratory research results and technologies into the
mainstream of the U.S. economy." May provide useful links with other federal
agencies.
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Section 6: Conclusions and Recommendations
1. SIM capability improvements will provide multiple public benefits, so there
are multiple reasons for public agencies to support R,D,T,&V in this area.
Substantial improvements to the state-of-the-art of structural integrity monitoring
will yield health, water quality, water conservation, asset management, and
economic benefits to water utilities and the public. These benefits will occur over
both the short-term and the long-term. The most obvious health-related benefit
will be reduction in preventable high risk water main breaks and their associated
health risks from loss of pressure, which can cause backflow and intrusion of
contaminants, and suspension of contaminated sediments. Reduction in high
consequence main breaks also provides a substantial economic benefit from
avoided response and damage costs. Another important benefit of improved SIM
capability is more optimized R3 scheduling, which helps to ensure that pipes are
used as long as safely possible. Other beneficial spinoffs may occur, such as
new preventive maintenance technologies made feasible by more
comprehensive, timely, and precise data on pipe deterioration.
2. Consensus, quantitative benefit, cost, and performance targets for SIM
capability improvements would be useful. The development of better
distribution system structural monitoring technologies for water mains can be
accelerated by attracting more attention from the federal and non-federal
research community. More attention to SIM research needs can be created by
generating and publicizing consensus, quantitative performance-, benefit-, and
cost-improvement targets for inspection and condition assessment technologies
for various critical application scenarios. These targets must be developed in
close coordination with the user community and technical experts. This topic is a
good candidate for an EPA-AwwaRF collaborative effort.
3. Advanced structural integrity monitoring technologies and procedures
should be developed first for applications where they are most likely to
have favorable benefit-cost ratios. These application scenarios include those
where main breaks are expected to produce: high consequence of failure (e.g.,
major adverse effects on customers, utilities, or communities) and high
frequency, moderate consequence failures (e.g., earthquake-prone areas,
systems with a substantial amount of deteriorated pipes). Advanced SIM may
also be particularly beneficial for monitoring new technologies to provide cost and
performance decisions for new technologies that have limited documentation of
successful short-term and long-term performance under a range of real
conditions (e.g., new pipe materials or configurations, new liner technologies, and
new installation technologies). Finally, when very low-cost SIM technologies and
components are developed, then previous relevant applications that were
dismissed due to cost considerations become candidates for re-evaluation.
4. Government research support can be critical for addressing fragmented
problems whose solution will provide public benefits. The distribution
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system SIM problem and technology market are fragmented into numerous
smaller problems and markets for a variety of reasons (e.g., various types of pipe
materials, diameters, coatings, linings, configurations, and consequences of
failure). Multiple SIM technologies and procedures will require improvement to
substantially improve SIM capability on a national scale. Fragmentation reduces
the potential return on research investment by the private sector. The federal
government has previously played an instrumental role in supporting research
that led, for example, to development of acoustic methods for monitoring PCCP
deterioration, and for acoustic emission monitoring of leaks.
5. Vigorous, increased, systematic EPA-ORD and other government support
and participation is recommended to ensure that improvements to SIM
capability for distribution systems occur in a timely manner. The "water
infrastructure replacement era" has already started. Improved SIM capability for
supporting R3 decision-making will be particularly beneficial during the
"replacement era." The sooner SIM technology improvements are applied, the
greater will be the benefits. Government-supported acceleration of SIM
technology R,D,T&V helps ensure that promising inspection technologies get
timely consideration in the marketplace.
6. Federal R,D,T,&V capabilities should be used to accelerate, and complement
the AwwaRF infrastructure reliability research program.
a. ORD/NRMRL/WSWRD should work with AwwaRF to develop SIM cost
and performance improvement targets for the various classes of next-
generation SIM technology. EPA should promote R,D,T,&V in relevant,
existing EPA and other federal research programs.
b. ORD/NRMRL/WSWRD should evaluate the potential for cooperation
with AwwaRF in structural integrity monitoring and condition
assessment technology evaluations. Options include the EPA's ETV
program, Federal sites of opportunity (e.g., DOD, DOE, or General Services
Administration (GSA) sites) or at Federal testing sites (e.g., underground
pipeline test apparatus at EPA-Edison, NJ; distribution system simulator at
EPA-Cincinnati, OH; or DOE test facilities).
c. EPA should promote cooperative research and technology transfer
efforts among relevant Federal research organizations to address the
long-term drinking water mains structural integrity performance and
cost targets identified in consultation with AwwaRF and the user
community. Potential cooperating agencies include DOD, DOE, DOT,
NASA, and NSF.
7. This white paper should be circulated to relevant EPA and other Federal
Agencies as a first step to exploring options for improving intra-EPA and
intra-Federal coordination regarding SIM capability improvement for drinking
water infrastructure research to accelerate production of useful products and
data.
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8. ORD/NRMRL/WSWRD/UWMB should continue to be a champion/sponsor of
research on advanced SIM. Near-term targets should include technical and
economic evaluations of intelligent systems for monitoring structural integrity of
buried pipe systems, which is receiving increased attention for non-DW piping
systems; systems for monitoring strain caused by bedding washout; and perhaps
evaluation of leak detection as a method for identifying and prioritizing future main
break locations.
9. ORD/NRMRL/WSWRD/UWMB should evaluate the need for and, as
applicable, promote the use of its Pipeline Test Apparatus (PTA) for
evaluation of advanced SIM technologies. The PTA is potentially valuable for
controlled-condition evaluations of promising leak detection/location/quantification
devices; in-line inspection devices; external inspection devices; remote coating
inspection devices; smart/intelligent pipes; and decontamination procedures. A
number of improved in-line inspection devices should be produced from a series of
ongoing DOT and DOE projects for natural gas pipeline applications. The
evaluation of the PTA should include identification of any necessary modifications
to support the tests.
10. Understanding the limitations of SIM capability is important for setting
research and user priorities. It is important to identify and document the
technical and cost limitations of SIM and make this information available to
decision-makers. For example, if existing and/or feasible monitoring devices
cannot measure key structural parameters, or can only measure them with
insufficient accuracy or spatial and temporal coverage, it is very useful to document
these findings. This will prevent misapplication of research or utility funds to
systems or applications where the performance or cost of SIM does not or cannot
meet the required levels.
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19. Makar, J., and N. Chagnon. 1999. Inspecting Systems for Leaks, Pits, and
Corrosion. Journal of the American Water Works Association. Vol. 91, Issue 7.
pp. 36-46.
20. Makar, J.M. and Y. Kleiner. 2000. Maintaining Water Pipeline Integrity. Institute for
Research in Construction. National Research Council of Canada. NRCC-43986.
14pp.
21. Meegoda, Jay N., T.M. Juliano. 2002. Research, Development, Demonstration
and Validation of Intelligent Systems for Conveyance and Storage Infrastructure
(Draft Final Report). National Risk Management Research Laboratory, U.S. EPA
and U.S. Army Industrial Ecology Center. 94 pp.
22. O'Day, K.D., R. Weiss, S. Chiavari, D. Blair. 1986. Water Main Evaluation for
Rehabilitation/Replacement. American Water Works Association Research
Foundation. Denver, CO. 182 pp.
23. Rajani, B. and J. Makar. 2000. A Methodology to Estimate Remaining Service Life
of Grey Cast Iron Water Mains. Canadian Journal of Civil Engineering. Vol. 27, pp.
1259-1272.
24. Rajani, B., J. Makar, S. McDonald, C. Zhan, S. Kuraoka, C. Jen, M. Viens. 2000.
Investigation of Grey Cast Iron Water Mains to Develop a Methodology for
Estimating Service Life. AWWA Research Foundation. Denver, CO. 266 pp.
25. Smith, L.A., K.A. Fields, A.S.C. Chen, A.N. Tafuri. 2000. Options for Leak and
Break Detection and Repair for Drinking Water Systems. Battelle Press. Columbus,
OH. 163pp.
26. Stone, S., E.J. Dzuray, D. Meisegeier, A.S. Dahlborg, M. Erickson. 2002.
Decision-Support Tools for Predicting the Performance of Water Distribution and
Wastewater Collection Systems. Logistics Management Institute for WSWRD,
NRMRL, U.S. EPA. EPA/600/R-02/029. 97 pp.
27. Tafuri, A. 2000. Locating Leaks with Acoustic Technology. Journal of the American
Water Works Association. Vol. 92, No. 7. July. pp. 57-66
37
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28. Tafuri, A., L. Russo, and S. Stone. 2001. Decision Support Tools for Managing
Wastewater Collection Systems. In Conference Proceedings- A Collection System
Odyssey: Integrating O&M and Wet Weather Solutions. Water Environment
Research Foundation. July. 23 pp.
29. Tafuri, Anthony N. and Ariamalar Selvakumar. 2002. Wastewater collection system
infrastructure research needs in the USA. Urban Water. Vol. 4, Issue 1.
30. U.S. Environmental Protection Agency. 2002a. Potential Contamination Due to
Cross-Connections and Backflow and the Associated Health Risks - An Issues
Paper. Office of Ground Water and Drinking Water. August 13, 2002.
http://www.epa.gov/safewater/tcr/pdf/ccrwhite.pdf. 42 pp.
31. U.S. Environmental Protection Agency. 2002b. The Clean Water and Drinking
Water Infrastructure Gap Analysis. EPA-816-R-02-020. Office of Water.
Washington, DC. September. 50 pp.
32. U.S. Environmental Protection Agency. 2002c. The Clean Water and Drinking
Water Infrastructure Gap Analysis. EPA 816-F-02-017. EPA Office of Water. Sept.
2pp.
33. U.S. EPA. 2003. Total Coliform Rule and Potential Revisions and Distribution
System Requirements, http://www.epa.gov/safewater/tcr/tcr.html
34. Van Blaricum, V.L., JackT. Flood, Michael J. Szeliga, and James B. Bushman.
1998. Demonstration of Remote Monitoring Technology for Cathodic Protection
Systems: Phase II. FEAP TR 98/82. May. U.S. Army Construction and Civil
Engineering Research Laboratories. Champaign, IL. 43 pp.
35. Wall, M. and F. A. Wedgwood. 1998. Economic assessment of inspection - the
inspection value method. NDT.net. December. 8 pp.
http://www.ndt.net/article/ecndt98/reliabil/318/318.htm
36. Water Infrastructure Network. 2001. Infrastructure Now - Recommendations for
Clean and Safe Water in the 21st Century. February. 14 pp.
http://www.win-water.org/win_reports/pub2/pub_2_html/safe_clean_water.html
38
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39
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Appendices
Appendix 1. Examples of Recent High Consequence Main Breaks
Date
11/96
01/98
01/00
03/00
02/01
02/01
03/01
Location (Main Size)
Cranston, Rl (Unknown)
5th Avenue, New York,
NY (Unknown)
9500 Rhode Island Ave.,
College Park, MD (30-in)
841 to 853 Broadway
New York, NY (36-in )
Dallas, TX (84-in)
Fountain & Silverwood
Phila., PA (30-in)
38th St. & Franklin Blvd.
Cleveland, OH (30-in)
Key Damages
$2 million emergency repair
1 5 to 20 Mgal lost
Street Collapse
Flooding damage
Ruptured gas line
Business disruption
House de-stabilized
Flooding
Road buckled
14 businesses damaged
120 businesses ~ 2 weeks
30 homes affected
Initial assessment:
$1 ,000,000 - structure
$1,000, 000 -contents
Sewer damage
Upper hospital floors w/o water
several hours
Pressure loss
6 schools closed
Low water pressure
Boil water advisory
Street damage
Basement flooding
Home de-stabilized
> 1 MM gal lost
Reference
Fortner, 1999
www.ci.nyc.us/html/dep/html/de
p/html/watermain . html
www.inform.umd.edu/
Diamondback/00-01-
31/news3.html
www.state.ny.us/governor/pres
s/year 00/May 9_1_00.htm
www.dallas fire
rescue.com/press
items/02_08_01_html
www.phila.gov/water/press/rele
ases/index_15.html
www.cleveland.com/news/index
.ssf?/news/pd/C29flood.html
40
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Appendix 1. Continued
Date
Location (Main Size)
Key Damages
Reference
07/02
1900VickerySt. &
Interstate 30
Fort Worth, TX (30-in)
Roadway Flooding
-2 hydroplane accidents
Disruption of service to
2 hospitals, OK on backup
systems
www.nbc5i.com/news/155333S/
detail.html
10/02
Clay St. & Cullen Blvd.
Houston, TX (60-in)
12-block area affected
Evacuated homes via boat
Home & vehicle damage
$900,000 from city to repair
and replace homes
www.click2houston.com/news/1
718677/detail.html
abclocal.go.com/ktrk/news/206
3 local watermain.html
11/02
Chicago, IL(36-in)
Lake Shore Drive closed ~ 2
days
Sinkhole 30'w, 9'deep
Several cars submerged
Basement flooding
www.nbc5.com/news/1774221/
detail.html
01/03
18th & 19th St.,
Brooklyn, NY
N, R and W subway lines
disrupted
stacks.msnbc.com/local/wnbc/a
1458601 .asp
01/03
Pittsfield, MA (unknown)
Tank drained (300,000 gal)
Schools & businesses closed
Low pressure
Service disruption
~1,300 customers
Icing
www.pittsfield.org/news_2003/0
12903waterb.htm
08/03
9th & Lombard, Phila.
PA(8-in)
Flooded electrical service
One-day power outage
-26,000 homes
-businesses; 2 hospitals
kyw.com/news/local_story_
224122428.html
09/03
Detroit, Ml (48-in)
I-96 shut down
Damage to roadway
www.wndu.com/news/092003/n
ews_21656.php
41
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Appendix 2.1 Examples of Current SIM Research for Drinking Water Conveyance
Systems
Category
Problem
Characterization
Technology
R,D,T,&V
Materials
Multiple
Multiple
Polymer
Multiple
Multiple
Multiple
Multiple
Multiple
Polymer
Concrete
(PCCP)*
Year
2003
2003
2005
2003
2003
2003
2004
2004
2004
2002
Title
Health effects from distribution systems
(meetings, white papers)
Water distribution system management
system... for the planning of rehabilitation
integrating statistical failure models
Long-term performance prediction for
polyvinyl chloride pipe
Workshop on non-interruptive condition
assessment inspection devices for water
transmission mains
Techniques for monitoring structural
behavior of piping systems
Non-contact sensors for pipe inspection
by Lamb waves
Testing, condition assessment of joints in
water distribution pipelines
Pervasive monitoring & control of water
lifeline systems for disaster recovery
Intelligent systems for conveyance and
storage infrastructure
SBIR Phase II: Wireless acoustic
emission sensor system for quantitative
nondestructive evaluation and in situ
testing of prestressed concrete cylinder
pipe
Sponsor/No. *
EPA-OGWDW
NSF/01 18376
AwwaRF/2879
AwwaRF/2871
AwwaRF/2612
NSF/9901221
AwwaRF/2689
NSF/01 12665
EPA-DOD/ No.
97938349
NSF/9984235 &
9760242
* AwwaRF = American Water Works Association Research Foundation
EPA = U.S. Environmental Protection Agency
DOD = U.S. Department of Defense
NSF = National Science Foundation
OGWDW = Office of Ground Water and Drinking Water, Office of Water, EPA
PCCP = prestressed concrete cylinder pipe
R,D,T,&V = Research, development, testing, & verification
42
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Appendix 2.2 Current/Recent SIM Research for Non-Drinking Water Pipelines that is
Potentially Applicable to Drinking Water Conveyance Systems
Category
Problem
Characterization
Technology
R,D,T,&V
Materials
Multiple
* Polymer
* Multiple
* Metal
(Steel)
* Multiple
"Concrete
Multiple
Multiple
Multiple
Multiple
Metal
Year
1999
2000
1991
2002
2003
2004
2005
2005
(start)
Title
Fitness-for-service models and
procedures for metals, concrete/
cement, polymers, and composites
(Examples below)
* PE Lifespan Forecasting: Plastic
Piping Systems
* Recommended Practice for Fitness
for Service (API RP 579)
* Manual for Determining the
Remaining Strength of Corroded
Pipelines (ASME B31G-1991)
* MANTOP - maintenance management
scheduling based on probability of
failures and cost of consequences
Various models for predicting the
deterioration of concrete structures
(e.g., bridge decks exposed to road
salts)
User Costs in Seismic Risk
Management for Urban Infrastructure
Systems
Intellipipe - system for high speed
data transmission from sub-surface drill
bit to surface
Digital mapping of buried pipelines with
a dual array system
http://primis.rspa.dot.gov/matrix/
Intelligent systems for pipeline
infrastructure systems for pipeline
infrastructure reliability
http://primis.rspa.dot.gov/matrix/
Improved material performance and
other pipeline safety improvements
Sponsor/No.
Gas Technology
lnstitute/(98/0358)
American Petroleum
Institute
American Society of
Mechanical Engineers
Southwest Research
Institute
Multiple
NSF/9802151
DOE-lndustry
Partnership
U.S. DOT/
DTRS56-02-T-0005
NRC-Canada/ U.S.
DOT/U.S. DOI
DTRS56-00-X-0035
U.S. DOT/ DTRS56
-04-BAA-0002
43
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Appendix 2.2 Continued
Category
Technology R,D,T,&V
Materials
Metal
Metal
Metal
Metal
Metal
Metal
Metal
Plastic
Plastic
Year
2003
2004
2004
2004
2004
2003
2004
2004
2006
Title
Baseline study of alternative in-line
inspection vehicles
In-line stress measurement by
continuous Barkhausen method
Mechanical damage inspection by
magnetic flux leakage (MFL)
Enhancement of the long-range
ultrasonic method for the detection of
degradation in buried, unpiggable
pipelines
NoPig metal-loss detection system for
non-piggable pipelines
Advanced passive-acoustic leak
location and detection verification
system for underground fuel pipelines
Fiber optic sensor suite for corrosion
and flow-assurance monitoring in
deepwater flow/lines
Pipeline damage prevention -locatable
magnetic plastic pipe
Framework for integrating embedded
sensors in durability analysis of FRP
composites in civil infrastructure
Sponsor/No.
U.S. DOT
DTRS56-02-T-0004
U.S. DOT
DTRS56-02-T-0003
U.S. DOT
DTRS56-02-T-0002
U.S. DOT
DTRS56-02-T-0007
U.S. DOT
DTRS56-03-T-0006
DOD-ESTCP
CP-9904
NIST/ATP
00-00-4611
U.S. DOT
DTRS56-02-T-0006
NSF/0093678
44
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Appendix 2.3 Research for Non-pipeline Applications Relevant to SIM Improvement
Category
Technology
R,D,T,&V
Materials
Multiple
(Mult)
Mult
Mult
Mult
Mult
Mult
Mult
Mult
Mult
Mult
Mult
Year
Indef
Mult
2004
2004
2003
2007
Indef
Indef
Mult
On-
going
On-
going
Title
Federal Government NDT/NDE capability - personnel,
facilities, funds, and programs potentially applicable to
water infrastructure R,D,T,&V. For example, DOD
Nondestructive Testing Information Analysis Center
(NTIAC); WSWRD/EPA, DOE, and DOD have pipeline
test apparatus.
"Smart" or "intelligent" technologies from material-scale
to city-scale - SEE SMART/INTELLIGENT
TECHNOLOGIES TABLE
Structural health monitoring via SMART layer
Sensors and sensor networks
Intelligent naval sensors - grand challenge research
program - sensors that are 1 0X smaller; 1 0OX faster;
use 0.001X energy
Center for Embedded Network Systems -embedded
network sensing systems; small, energy scavenging
sensor systems - http://cens.ucla.edu/default/htm
Center for Infrastructure Technology Research in the
Interest of Society- energy scavenging sensors, smart
buildings - http://www.citris.berkeley.edu/program
Facility Environmental Monitoring and Management
Systems Program - improving monitoring technology
for ... water ... at arsenals
Structural integrity monitoring for bridges (e.g.,
http://www.di3.drexel.edu )
Sewers as fiber optic cable conduit-
http://www.citynettelecom.com/
Use of electric powerlines for transmitting data -
http://www.ambientcorp.com;
http://www.echelon.com/products/oem/transceivers/pow
erline/default.htm
Sponsor/No.
DOE; DOD;
EPA; DOT;
NASA; NIST,
etc.
Mult
NIST/ATP
00-00-4404
NSF/04-522
Office of Naval
Research
NSF/
0120778
UC Berkeley
DOD/
Industrial Ecol.
Center
Mult
Citynet Corp.
Mult
45
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Appendix 2.4 Examples of Smart/Intelligent Devices & Systems
Smart dust - small integrated sensing & data storage, analysis, &/or transmission devices.
Smart pebbles - U.S. DOT project to develop/test low-cost, stay-in-place, queriable sensors to
monitor chloride content from road salt in concrete bridge decks.
Smart bricks - bricks or other structural component outfitted with smart dust-type devices to
measure and report motion, vibration, etc.
Smart bolt - U.S. Air Force - deformation of wing anchor bolts made of TRIP (transformation
induced plasticity) steel can be monitored for deformation state without disassembly, reduces
inspection time and cost.
Smart nose - smart sensor for analysis of vapors, may be relevant structural monitoring if
volatile compounds indicate deterioration.
Smart tongue - smart sensor for analysis of compounds in water, may be relevant for
structural monitoring if dissolved compounds indicate deterioration.
Smart pigs - several organizations (e.g., AwwaRF, DOT, DOE, & private sector are conducting
research on in-line pipe inspection devices with sensors to detect and record a variety of
structural parameters.
Smart pipe - incorporation of sensing capability into pipe. Sensors may monitor fluid, pipe, or
loading parameters; sensor location and spacing may vary widely.
Smart structures and buildings - buildings equipped with sensors (e.g., vibration, orientation,
motion, and strain) in key locations that enable rapid assessment of structural stability.
Reductions in cost of sensor increase economic feasibility of denser sensor arrays.
Intelligent systems - integration of sensing, data storage, remote data analysis, data
transmission, detailed central analysis, condition assessment to support proactive, condition-
based maintenance. EPA, DOD, DOT, DOE, and NIST have research projects in this area.
46
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Appendix 3. Examples of Interagency Collaboration Opportunities
Project Title/Goal/Description:
Potential
Collaborators
R,D,T,&V of Intelligent Systems for SIM Applications
EPA and DOD recently completed one interagency agreement on intelligent systems for
conveyance and storage systems. Other opportunities for collaboration exist with DOD (e.g.,
smart materials, pipelines), DOE (e.g., smart pipes, smart cities), NIST (e.g., smart layer
technologies), DOT (e.g., intelligent pipelines for system reliability), and NSF (e.g., sensing and
civil and mechanical systems research programs).
EPA, DOD, DOE,
NIST, DOT, NSF
Improvement of In-Line and External Inspection Technologies
The DOE's Strategic Center for Natural Gas and Oil (SCNGO) in its National Energy
Technology Laboratory (NETL) and the DOT's Office of Pipeline Safety (OPS), have leading
roles in promoting, funding, and performing structural integrity monitoring research,
development, and demonstration projects for gas and hazardous liquid pipelines. Between
DOE and DOT there are over 40 active structural integrity management technology projects.
DOE's FY-03 budget for gas pipeline integrity research was about $7 million.
EPA, DOE, DOT
Integral Communication, Damage Detection, and Multiple Sensor Applications in
Pipelines/DOE Project No.: FWP-4340-70A/http://www.netl.doe.gov/scng/
Goal (DOE): The ultimate goal is to obtain real-time information concerning the pipeline
infrastructure so that the security of the system can be assured and efficiency of the system
can be maximized.
Description (DOE): In this project, thermal spray was used to deposit fine metallic powders,
wire, or even non-metallic materials on sections of pipe. Its ability to be utilized for data
transmission or to detect third party damage was evaluated. DOE Phase I - 7/2001 to 9/2002.
EPA & DOE
Title (EPA): Improvement and evaluation of above ground survey technology for buried
pipelines
Goal (EPA): Verification and/or improvement of non-invasive technology for buried metallic
pipelines.
Description (EPA): Possible cooperative project with water utility that has been evaluating a
private company's above ground pipeline survey technology. First set of tests by utility on large
diameter pipelines identified the pipeline alignment, depth, and picked-up all non- isolated
service connections and laterals. Utility is interested in a partnership project to further develop
and evaluate the device. Improvements sought include capability to identify soil condition,
moisture content, corrosion pitting and other symptoms indicative of severe pipeline
degradation.
EPA & DOT &/or
DOE &/or NSF
47
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Appendix 3. Continued
Project Title/Goal/Description:
Potential
Collaborators
Title (DOT): NoPig Metal-Loss Detection System for Non-Piggable Pipelines/ DTRS56-03-
T-0006 - http://ops.cycla.com/matrix/
Goal (DOT): The project goals are to: confirm the NoPig System provides accurate pipeline
metal-loss detection within present specifications; improve the system to be able to discriminate
between defects; and, apply the technology to larger diameter pipelines for metal-loss detection
and discrimination.
Description (DOT): The NoPig Pipeline Inspection System has been developed as a method
for detecting metal loss anomalies on small diameter non-piggable pipelines from above
ground. Contact points at two places no farther than 500 meters from each other are needed.
The technology makes use of the skin effect. It utilizes a difference between magnetic fields at
low and high frequency produced by electric currents passed through the pipe under test. The
low frequency current will distribute itself and travel throughout the entire cross section of the
pipe. The high frequency current will travel along the outer surface of the pipe (skin effect).
Both currents generate a magnetic field which shape is dependent on the presence of a defect.
Project Period: 07/2003 to 07/2005.
EPA & DOT
Title (DOE): New Acoustic Wave Pipe Inspection System/ DOE Project No.:
FEAB201/URL: http://www.netl.doe.gov/scng/
Goal (DOE): To demonstrate a new wave guide pipe flaw detection technique that will detect
flaws in a single pass.
Description (DOE): The technical approach is to use an acoustic signal directed through the
walls of the pipe and along the length of the pipe. Acoustic receivers utilizing microcantilever
sensors will detect reflected, dispersed, and scattered signals to which advanced signal
processing methods will be applied to identify such flaws as cracks, corrosion pits, gouges, and
leaks. These sensors, receivers, and actuators will be integrated into a compact (4 to 5 inches
in diameter by 24-inch long) in-line inspection tool suitable for transmission and distribution
pipelines. Project Period: 08/2001 to 11/2003.
EPA & DOE
Title (DOE): A Data Fusion System for the Non-Destructive Evaluation of Non-Piggable
Pipes/DOE Project No.: DE-FC26-02NT41648/URL: http://www.netl.doe.gov/scng/
Goal (DOE):To design sensor data fusion algorithms that can synergistically combine defect-
related information from heterogeneous sensors.
Description (DOE): These sensors are used to inspect natural gas pipelines for reliably and
accurately predicting the condition of the pipe-wall. This work will also develop efficient data
management techniques for signals obtained during multi-sensor interrogation of a gas
pipeline. Project Period: 09/2002 to 09/2004; DOE Cooperative Agreement with Rowan
University.
EPA & DOE
48
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