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<pubnumber>600R09049</pubnumber>
<title>Condition Assessment of Wastewater Collection Systems - White Paper</title>
<pages>74</pages>
<pubyear>2009</pubyear>
<provider>NEPIS</provider>
<access>online</access>
<origin>PDF</origin>
<author></author>
<publisher></publisher>
<subject></subject>
<abstract></abstract>
<operator>mja</operator>
<scandate>06/11/09</scandate>
<type>single page tiff</type>
<keyword></keyword>

United States
Environmental Protection
Agency
                                     EPA/600/R-09/049 | May 2009 | www.epa.gov/nrmrl
                   Condition Assessment of
                   Wastewater Collection Systems
                   WHITE PAPER
  Office of Research and Development
  National Risk Management Research Laboratory - Water Supply and Water Resources Division

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               United States        Office of Research    Final Report
               Environmental Protection    and Development    May 2009
               Agency          Washington, DC 20460   EPA/600/R-09/049
&EPA       White Paper on
               Condition Assessment of
               Wastewater Collection
               Systems

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                     White Paper on
Condition Assessment of Wastewater Collection
                          Systems
                              by

                      Christopher S. Feeney
                   The Louis Berger Group, Inc.
                          Scott Thayer
                      Redzone Robotics, Inc.
                        Michael Bonomo
                 ADS Environmental Services, LLC

                        Kathy Martel, P.E.
                       The Cadmus Group
                      Contract No. EP-C-05-058
                        Task Order No. 59
                       Task Order Manager
                   Dr. Fu-hsiung (Dennis) F. Lai
              Water Supply and Water Resources Division
                 2890 Woodbridge Avenue (MS-104)
                         Edison, NJ 08837
            National Risk Management Research Laboratory
                 Office of Research and Development
                U.S. Environmental Protection Agency
                      Cincinnati, Ohio 45268

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                                         Disclaimer

The U.S. Environmental Protection Agency, through its Office of Research and Development, funded and
managed, and collaborated in the research described herein.  It has been subjected to the Agency's peer
and administrative review and has been approved for publication. Any opinions expressed in this report
are those of the author(s) and do not necessarily reflect the views of the Agency, therefore,  no official
endorsement should be inferred. Any mention of trade names or commercial products does not constitute
endorsement or recommendation for use.

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                                         Contents

Disclaimer                                                                                ii

Contents                                                                                 iii

List of Figures                                                                            v

List of Tables                                                                             v

Symbols and Acronyms                                                                  vi

Executive Summary                                                                       1

1.0    Overview of Task Order 59                                                      1-1
       1.1    Project Background                                                         1-1
       1.2    Purpose and Scope                                                           1-1
       1.3    Definition of Terms                                                         1-2
       1.4    Critical Gaps in Inspection Technologies and Condition Assessment                1-3
               1.4.1   Gravity Line Inspection                                               1-4
               1.4.2   Pressure Line/Force Main Inspection                                    1-4
               1.4.3   Condition Assessment Protocols                                        1-4
       1.5    Research Questions                                                          1-4

2.0    Condition Assessment                                                            2-6
       2.1    Program Development                                                       2-7
       2.2    Asset Inspection                                                             2-8
              2.2.1   Selection of Assets for Inspection                                       2-8
              2.2.2   Prioritization of Assets                                                 2-9
              2.2.3   Asset Inspection                                                      2-9
       2.3    Data Management                                                           2-9
              2.3.1   Condition Assessment/Asset Management Software                       2-9
              2.3.2   General Database Management Software                                2-10
              2.3.3   Spreadsheet Software                                                2-10
       2.4    Data Analysis                                                              2-10
              2.4.1   Hydraulic Capacity/Hydraulic Restrictions                              2-10
              2.4.2   Structural Condition                                                 2-11
       2.5    Decision Making                                                           2-13

3.0    Dynamics of Wastewater Collection System Failure                             3-16
       3.1    Failure Mechanisms                                                        3-16
              3.1.1   Hydraulic Re strictions                                                3-16
              3.1.2   Hydraulic Capacity                                                  3-16
              3.1.3   Structural Failure                                                    3-17
       3.2    Pipe Defects                                                               3-18
       3.3    Correlations between Assessed Conditions and Performance Measures             3-19

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4.0    Inspection Technologies                                                         4-21
       4.1    Camera Inspection                                                         4-22
              4.1.1   Zoom Camera Inspection                                             4-23
              4.1.2   Digital Scanning                                                    4-25
              4.1.3   Camera Deployment                                                 4-27
       4.2    Acoustic Technologies                                                      4-30
              4.2.1   Leak Detectors                                                      4-31
              4.2.2   Acoustic Monitoring Systems                                         4-33
              4.2.3   Sonar and Ultrasonic Testing                                          4-34
       4.3    Electrical and Electromagnetic Methods                                       4-35
              4.3.1   Electrical Leak Location Method                                      4-36
              4.3.2   Eddy Current Testing and Remote Field Eddy Current Technology         4-37
              4.3.3   Magnetic Flux Leakage Detection                                     4-40
       4.4    Laser Profiling                                                             4-41
       4.5    Flow Meters                                                               4-42
       4.6    Innovative Technologies                                                    4-43
              4.6.1   Gamma-Gamma Logging                                             4-43
              4.6.2   Ground Penetrating Radar                                            4-44
              4.6.3   Infrared Thermography                                              4-44
              4.6.4   Micro-Deflection                                                    4-45
              4.6.5   Impact Echo/Spectral Analysis of Surface Waves (SASW)                4-45
              4.6.6   Ultrasonic Testing Systems                                           4-45

5.0    Technology  Forum Summary                                                   5-46
       5.1    Background                                                               5-46
       5.2    General Discussion                                                         5-46
       5.3    Critical Gaps Identified in State of the Science                                 5-47
       5.4    Recommended Next Steps                                                   5-48

6.0    References                                                                      6-50

Appendix A                                                                            A-l
       Camera Technologies                                                               A-2
       Acoustic Technologies                                                              A-5
       Electrical and Electromagnetic Products                                               A-7
       Laser Products                                                                     A-9

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                                     List of Figures
Figure 2-1:  Condition Assessment
Figure 5-1:  Technology Forum Attendees
 2-6
5-49
                                     List of Tables

Table ES-1: Summary of Emerging and Innovative Technologies
Table 2-1:  Condition Assessment Matrix
Table 3-1:  Most Common Pipe Defects Identified
Table 4-1:  Inspection Technology Overview
Table 4-2:  Zoom Camera Inspection Summary
Table 4-3:  Digital Camera Scanning Inspection Summary
Table 4-4:  Pushcam Product Comparison
Table 4-5:  Lateral Launcher Product Comparison
Table 4-6:  Small Diameter Tractor Product Comparison
Table 4-7:  Long Range Tractor Product Comparison
Table 4-8:  Acoustic Technology Summary
Table 4-9:  Sonar Product Comparison
Table 4-10: Electrical and Electromagnetic Methods Summary
Table 4-11: MFL Product Comparison
Table 4-12: Laser Profiling Summary
ES-4
2-15
3-19
4-21
4-24
4-26
4-28
4-29
4-29
4-29
4-31
4-35
4-36
4-41
4-41

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                                Symbols and Acronyms
2D           Two dimensional
3D           Three dimensional
A             Access point
ACI          American Concrete Institute
AET          Acoustic emission testing
AwwaRF      American Water Works Association Research Foundation (now Water Research
              Foundation)
B             Broken
BEM         Broadband electromagnetic methodology
BW          Brick work
C             Crack
CARE-S       Computer Aided Rehabilitation Program for Sewers
CCTV        Closed-Circuit Television
CDMA        Code Division Multiple Access
CMOM       Capacity, Management, Operation and Maintenance
CWA         Clean Water Act
D             Deformed or deposits
DVD         Digital video discs
ECT          Eddy current testing
EDGE        Enhanced Data Rates for Global Evolution
EPA          Environmental Protection Agency
F             Fracture
FELL         Focused Electrode Leak Location System
FL           Longitudinal fracture
FMEA        Failure Mode and Effects Analysis
ft.             feet
GIS          Geographic Information System
gpm          gallons per minute
gpm/in-mile    gallons per minute per inch diameter per mile length
GPR          Ground penetrating radar
GPRS         General Packet Radio Service
GPS          Global positioning system
H             Hole
HOPE        high density polyethylene
HSV          Hole with visible soil
I             Infiltration
I/I            Inflow and infiltration
in.            inches

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IP            internet protocol
IRT           Infrared thermography
IS            Intruding seal material
J             Joint
KPI           Key performance indicator
L             Line
LED          Light-emitting diode
LF            Lining failure
M            Miscellaneous
MACP        Manhole Assessment Certification Program
MCU         Camera underwater
MFL          Magnetic flux leakage
NA           Not applicable
NACWA      National Association of Clean Water Agencies
NASSCO      National Association of Sewer Service Companies
OB           Obstacles
O&M         Operations and Maintenance
ORD          Office of Research and Development
PACP         Pipeline Assessment Certification Program
PCCP         Pre-stressed concrete cylinder pipe
PR           Point repair
psi            pounds per square inch
PTZ           Pan-Tilt-Zoom
PVC          Polyvinyl chloride
R             Roots
RCP          Reinforced concrete pipe
RFEC         Remote field eddy current
RFEC/TC      Remote field eddy current/transformer coupling
S             Surface damage
SASW        Spectral Analysis of Surface Waves
SCADA       Supervisory Control and Data Acquisition
SCRAPS      Sewer Cataloging, Retrieval, and Prioritization System
Sonar         Sound navigation and ranging
SSET         Sewer scanning evaluation technology
SSO           Sanitary sewer  overflow
T             Tap
TC           Transformer coupling
U.S.           United States of America
USEPA       United States Environmental Protection Agency
VCP          Vitrified clay pipe
V             Vermin

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VR           Vermin including rats
WEF         Water Environment Federation
WERF        Water Environment Research Federation
WF           Weld failure
WRc         Water Research Centre (United Kingdom)
X            Collapse

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                                    Executive Summary

In 2007, the United States Environmental Protection Agency (USEPA) finalized a research program
entitled "Innovation and Research for Water Infrastructure for the 21st Century" that will generate the
science and engineering knowledge needed to improve and evaluate innovative technologies to reduce the
cost while improving the effectiveness of operation, maintenance, and replacement of aging and failing
drinking water and wastewater treatment and conveyance systems (USEPA, 2007). Task Order 59,
Condition Assessment of Wastewater Collection Systems, is one of several projects being conducted
under this research initiative.

Overview
The objectives of Task Order 59 are to comprehensively review condition assessment technologies and to
investigate condition assessment approaches for wastewater collection systems.  Specific project
objectives include:

       •   Identify and characterize the state of condition assessment technology for wastewater
           collection systems.
       •   Research and evaluate performance and cost of innovative and advanced infrastructure
           monitoring technologies including wireless and remote sensing approaches developed in
           other industries and their applicability to wastewater collection sewers.
       •   Identify and evaluate innovative closed-circuit television (CCTV) technologies currently used
           by more advanced wastewater utilities for transfer to utilities at large.
       •   Prepare protocols, metrics, and site selection criteria for field demonstration of selected
           innovative condition assessment technologies and decision-support systems.

This White Paper is one of the first work products created under Task Order 59 and was used as a basis
for discussions at the project's Technology Forum in September 2008.  The White Paper summarizes the
current state of condition assessment technologies, reviews mechanisms of pipe failure, discusses
emerging and innovative technologies for sewer inspection,  and presents a summary of the Technology
Forum. It incorporates feedback received at the Technology Forum.

Condition Assessment
The primary components of any asset management program include the identification, location, and
condition of assets. Condition assessment provides the critical information needed to assess the physical
condition and functionality of a wastewater collection system, and to estimate remaining service life and
asset value. After the field inspection, pipe defects are classified using a standard coding system and pipe
condition is assessed using a systematic method to produce consistent, useful information. Following
data analysis, condition assessment information is used to make estimates of a pipe's remaining useful life
and its long-term performance, and to make decisions about pipe rehabilitation, pipe replacement and/or
further inspections.

Dynamics of Wastewater System Failure
In conducting condition assessment, it is important to understand the dynamics of pipe failure including
the level, type, and severity  of a failure mechanism.  Failure can be a sudden, catastrophic collapse of a
pipe, restricted hydraulic capacity, or a variety of other performance conditions that result in the inability
of the pipe to perform as necessary for the minimum acceptable level of operation of the system. The
purpose of condition assessment is to detect pipe defects which indicate the likelihood of pipe failure, as
well as to assess the collection system's performance. This section discusses the  mechanisms of pipe
failure, the various types of pipe defects, and the relationship between the condition of a pipe and its
                                            Page ES-1

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performance. It is important to understand that the mechanisms and impacts of pipe failure are highly
dependent upon the pipe material and type of sewer (i.e. force main, gravity line).

Inspection Technologies
There are a variety of technologies available for assessment of collection systems. These technologies,
summarized in Table ES-1, include:
        •  CCTV is a well-established and common industry method used for inspecting pipes. It
           provides visual data on leaks, location of service laterals,  and sediment and debris
           accumulation. The primary disadvantages to CCTV technology are that it only provides a
           view of the pipe  surface above the waterline; it does not provide any structural data on the
           pipe wall integrity; and it does not provide a view of the soil envelope supporting the pipe.
           For inspections of gravity lines, basic CCTV systems are  not able to measure slope.  There
           are needs for higher resolution cameras with better lighting; and improvements in crawler
           technology to better negotiate obstructions, grease, and off-set joints.  The quality of defect
           identification and pipe condition assessment using CCTV is highly dependent on many
           factors including operator interpretation, picture quality, and flow level. Innovative camera
           technologies include zoom cameras, digital inspection, push cameras, and advances in
           crawler technology.
        •  Acoustic technologies use measuring devices to detect vibrations and/or sound waves. In
           pipeline assessment, acoustic sensors are used to detect signals emitted by defects. Three
           types of acoustic technologies are used for pipeline assessment: leak detectors, which are
           used to detect the acoustic signals emitted by pipeline  leaks; acoustic monitoring systems,
           which are used to evaluate the condition of pre-stressed concrete cylinder pipe (PCCP) by
           detecting the signals emitted by breaking pre-stressed wires; and sonar, or ultrasonic systems,
           which emit high  frequency sound waves and measure their reflection in order to detect a
           variety of pipe defects.
        •  Electrical/Electromagnetic currents are the basis of several sewer evaluation techniques.
           The electrical leak location method is used to detect leaks in surcharged non-ferrous pipes.
           Eddy Current Testing (ECT) and Remote Field Eddy Current (RFEC) technology identify
           defects in ferrous pipes.  Magnetic Flux Leakage (MFL) inspection is widely used in the oil
           and gas industry to measure metal loss and  detect cracks in ferrous pipelines.
        •  Laser profiling uses a laser to create a line  of light around the pipe wall, highlighting the
           shape of the sewer.  This technique allows for the detection of changes to the pipe's shape,
           which may be caused by deformation, corrosion, or siltation. Laser inspection can only be
           used to inspect the portions  of a pipe wall that are above the water line.  To assess the entire
           internal surface of a pipeline requires the pipe to be taken out of service.  Lasers are often
           used in combination with other inspection methods, most  commonly CCTV and/or sonar.
        •  Innovative methods based on a variety of technologies are currently being developed for the
           evaluation of sewer collection systems. Gamma-gamma logging is a technique used
           primarily to evaluate cast-in-place concrete pilings and can provide information on the
           average bulk density of the concrete and the location of voids.  Ground Penetrating Radar can
           detect underground voids, and is potentially useful for examination of pipe bedding and to
           locate leaks.  Infrared Thermography involves the use  of an infrared camera to measure the
           temperature differential across an object and is a potential method of detecting sewer defects
           such as leaks and voids.  Micro-Deflection is a nondestructive technology used to evaluate
           general conditions and joint integrity of brick, concrete, and clay structures using a load to
           create a slight deformation or micro-deflection in the test  material. Impact Echo and Spectral
           Analysis of Surface Waves (SASW) are acoustic wave techniques for locating and measuring
           cracks, delaminations, voids, and honeycombing in concrete and masonry.
                                            Page ES-2

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Summary of Technology Forum
A technology forum was held on September 11 and 12, 2008 in Edison, New Jersey to discuss the state of
the science for condition assessment of wastewater collection systems and to identify critical gaps in
current knowledge.  A draft of the White Paper was distributed to participants in advance of the meeting
and served as a basis for forum discussions. The objective of the forum was to present the findings of the
research and obtain direction for additional research and further evaluation during the field demonstration
tasks. The forum included discussions on data needs for conducting condition assessment and making
asset management decisions; use of flow monitoring for asset management; systematic approaches to
condition assessment; the importance of understanding the mechanisms of pipe failure; and tools and
models available for conducting risk-based decision making related to wastewater assets.
Critical gaps in our knowledge of inspection technologies, and our ability to diagnose and predict
infrastructure failures were identified at the Technology Forum and summarized below.

        1.  Research is needed to further define the costs and benefits of pipe inspection and
           rehabilitation as part of a utility's condition assessment program. Methods of determining the
           impact of deteriorating collection systems on municipal budgets are  needed.
        2.  Inspection technologies need to be identified for the following applications:
             a.   Reduce use of confined space entry during sewer system inspections and investigations.
             b.   Affordable inspection technology that utilizes multi-sensor devices on a small
                 transportable package.
             c.   Inspecting pipes below the waterline.
             d.   Inspecting force mains that are in service.
             e.   Inspecting laterals.
        3.  Data management methods and models are available, but a lack of data standardization makes
           it difficult to compare historical data collected with different inspection technologies that
           have proprietary data structures.
        4.  Research is needed to improve how asset condition is tracked over time. Geospatial
           information (with a high degree of accuracy) needs to be collected along with pipe condition
           data in order to link historical inspection data with an exact physical location.

Information transfer to practitioners was identified as a critical industry need. Practitioners need training
on topics such as infrastructure failure mechanisms; using historical inspection data for condition
assessment applications; applying the Pipeline Assessment Certification Program (PACP) coding system
to characterize pipe defects; developing a condition assessment program; and preparing accurate  record
drawings for new and rehabilitated pipe. In addition, practitioners need simple condition assessment tools
(i.e. scattergraphs for analyzing flow data, decision trees, rules of thumb).
                                            Page ES-3

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Table ES-1: Summary of Emerging and Innovative Technologies
Technology
Application
Pipe type
Pipe material
Pipe size
Defects Detected
Sediment, debris, roots
Pipe sags & deflections
External pits & voids
Corrosion & metal loss
Off-set joints
Pipe cracks
Leaks
Broken pre-stressed wires
Wall thickness
Service connections
Bedding condition
Bedding voids
Deteriorated insulation
Overall condition
CCTV
Conventional

G
Any
>6"

•
•


•
•
•


•




Zoom camera

G
Any
>6"

•
•


•
•
•


•




Digital scanning

G
Any
6"-60"

•
Partial

Partial
Partial
•
•







Push-camera inspection

S
Any
1"-
12"

•
•


•
•
•


•




Acoustic
In-line leak detectors

G,F
Any
>4"







•







Acoustic monitoring
systems

F
PCCP
>18"








•






Sonar/ultrasonic

G,F
Any
>2"

•
•
•
•

•








Electrical &
Electro-magnetic
Electrical leak location

G,F, S
NF
>3"






•
•







Remote field eddy current

G,F,S
F
>2"




•

•
•
•
•





Magnetic flux leakage

G,F,S
F, PCCP
2"-56"




•

•








Lase
r
Laser profiling

G,F
Any
>4"

•
•

•










Innovative Technologies
00
'oo
00
_o
cS
§
cS
00
^
o

G,F,S
C
Not yet
defined



•






•
•
•


Ground penetrating radar

G,F,S
Any
Not yet
defined







•



•
•


>>
I*
00
0
JH
i
S
^

G,F,S
Any
Not yet
defined







•




•
•

Micro-deflection

G
B
Not yet
defined



Partial








Partial

•
Impact echo/SASW

G
B,
C
>6'



•


•


•





                     Pipe type:   G - Gravity line   F-Force main  S - Service lateral
                  Pipe material:   NF - Nonferrous  F - Ferrous   B - Brick   C - Concrete   PCCP - Pre-stressed concrete cylinder pipe
                                                                         Page ES-4

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                           1.0    Overview of Task Order 59

In 2007, USEPA finalized a research program entitled "Innovation and Research for Water Infrastructure
for the 21st Century" that is being implemented by the Office of Research and Development. It will
generate the science and engineering knowledge needed to improve and evaluate innovative technologies
to reduce the cost while improving the effectiveness of operation, maintenance, and replacement of aging
and failing drinking water and wastewater treatment and conveyance systems (USEPA, 2007).  Task
Order 59, Condition Assessment of Wastewater Collection Systems, is one of several projects being
conducted under this research initiative.


1.1    Project Background

In 2002, the USEPA Office of Water published a report entitled "Clean Water and Drinking Water
Infrastructure Gap Analysis" (USEPA, 2002). The Gap Analysis report identified a critical shortfall in
funding of the nation's water and wastewater infrastructure including a $270 billion gap for wastewater
infrastructure for the years 2000-2019. The deferred maintenance approach to operating and maintaining
the nation's aging wastewater infrastructure has become a paramount concern of the Agency.
Failing wastewater infrastructure can pose a significant threat to public health and the environment.
Wastewater infrastructure may include sanitary and combined sewer components, but this project is
focused only on sanitary sewer systems.  Systems with inadequate hydraulic capacity and/or blockages
may lead to sanitary sewer overflows (SSOs)  and may cause flooding damage to private property or
release untreated sewage to receiving waters.  Some of the health hazards associated with basement
flooding by untreated wastewater include the  potential presence of pathogenic microorganisms such as
viruses, bacteria, and protozoa.
USEPA and State regulators have taken legal action against utility districts for property damage and
SSOs.  For example, in 2005, a settlement of  $300 million was reached with the Washington Suburban
Sanitary Commission to implement a program to reduce occurrences of basement flooding. This joint
settlement was reached among the utility district, USEPA,  State of Maryland, and five local citizens
groups. In 2004, Knoxville Utility Board reached a settlement with the State of Tennessee for a capital
improvements program of $350 million to eliminate flooding due to hydraulic restrictions.  In 2004,
Hamilton, Ohio reached a settlement to implement a program to eliminate SSOs and basement flooding
that was estimated to cost approximately $1.5 billion.


1.2    Purpose and Scope

The objectives of Task Order 59 are to comprehensively review condition assessment technologies and to
investigate condition assessment approaches for wastewater collection systems. The primary goal of the
project is to develop more efficient and cost-effective means to conduct condition assessment and to use
the information as part of a risk-based asset management approach to planning. Specific project
objectives include:


       •   Identify and characterize the state of condition assessment technology for wastewater
           collection systems.
       •   Research and evaluate performance and cost of innovative and advanced infrastructure
           monitoring technologies including wireless and remote sensing approaches developed in
           other industries and their applicability to wastewater collection sewers.
       •   Identify and evaluate innovative CCTV technologies currently used by more advanced
           wastewater utilities for transfer to utilities at large.
                                           Page 1-1

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        •   Prepare protocols, metrics, and site selection criteria for field demonstration of selected
           innovative condition assessment technologies and decision-support systems.

To meet these project objectives, a stakeholder group was established to review all task products, and a
technology forum was convened to help compile and assess the current state-of-the-art and evolving
technologies including any critical gaps in performance, affordability or applicability to wastewater
collection systems.  During the literature review for the White Paper, internal camera inspection
technologies were researched and evaluated for immediate transfer to utilities at large; advanced integrity
assessment technologies that apply non-contact, remote sensing approaches were also reviewed. In the
main portion of the project, protocols/metrics for field demonstration of selected technologies will be
developed, as will criteria for selecting demonstration sites. Finally, field demonstrations of select
technologies will be conducted.
The work products resulting from the project will include:
        •   White paper summarizing current state of the technology.
        •   Summary of technology forum discussions and findings.
        •   Comprehensive inventory of condition assessment technologies.
        •   Information transfer document on internal camera inspection technologies.
        •   Information transfer document on advanced integrity monitoring technologies.
        •   Quality assurance project plan for conducting field demonstrations and data analysis.
        •   Technical memoranda summarizing each task.
        •   Final project report.

A draft white paper was prepared and used as a basis for discussion at the project's Technology Forum
held in Edison, NJ on September 11 and 12, 2008.  It was distributed to the expert panel, stakeholders and
other participants in advance of the meeting. This final white paper incorporates feedback received at the
Technology Forum.


1.3     Definition of Terms

A wastewater collection system or sanitary sewer system is defined as the network of pipes and pumping
systems used to convey sanitary flow to a wastewater treatment facility for treatment prior to discharge to
the environment. A wastewater collection system is designed to convey only sanitary flow, whereas a
combined system is designed to convey sanitary and storm water flows.
A gravity line is a sewer pipe that is sloped to convey flow via gravitational forces. Typical design
standards are based on open channel flow equations under normal flow conditions utilizing Manning's
equation.  Design criteria for a gravity line generally take into consideration anticipated defects as a pipe
remains in service. An allowable rate of inflow and infiltration expressed in terms of gallons per minute
per in. diameter per mile length (gpm/in-mile) is included in hydraulic design of gravity lines. It is also
typical to select a frictional coefficient that is based upon a sediment accumulation at the invert of the
pipe.  The minimum diameter of a gravity line (excluding service laterals) is typically 8 inches (in.);
however, large interceptors can have diameters in excess of 12 feet (ft).  Older systems may contain 6-in.
gravity lines.
Service laterals are the gravity lines that convey wastewater from a building's foundation to the sanitary
line, or main, in the street.  The ownership of the service lateral varies widely from area to area. It may be
defined by property line limits, with the private sewer lateral extending from the house or building
foundation to the property line and the municipal or public lateral located within the public right of way.
In other cases, the property owner may own the service lateral all the way to the main.
                                            Page 1-2

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A force main is a pressure line used to convey pumped sewage. The Water Environment Research
Federation (WERF) 2004 survey indicated that force mains comprise, on average, 7.5% of a collection
system. This percentage does vary considerably depending on the region and the topography.
Approximately 46% of the force mains have diameters less than 12-in. and 20% are greater than 36-in.
The most common pipe materials for force mains are cast iron and ductile iron.
Asset Management - The primary components of any asset management program include the
identification, location, and condition of assets; the determination of their useful life and their valuation.
The key to asset management is to understand the types, frequency, and costs of failure. Asset
management often employs a risk-based management approach that utilizes information on asset failures
as part of a decision making model to manage funding and maintenance priorities.  One risk model often
employed is Failure Mode and Effects Analysis (FMEA).  FMEA analyzes a system's potential failure
modes so they can be classified by severity or determination of the effect upon the system. It is widely
used in manufacturing as a risk mitigation tool in various phases of product life cycle and product  quality
planning.
The Water Research Foundation (formerly the American Water Works Association Research Foundation
(AwwaRF)) and the Water Environment Federation (WEF) have both produced guidance documents on
asset management and risk-based analysis of assets. The Capacity, Management, Operation and
Maintenance (CMOM) program also outlines the framework necessary to develop an information-based
strategy on managing assets.  Such approaches are not unique to the wastewater industry. Developing an
understanding  of the risks and potential costs of system failure can aid in the decision making process.
Condition assessment is one of the core components of an asset management program.  It provides the
critical information needed to assess the condition and remaining useful life and long-term performance
of a piping system.  Condition assessment can also be used to determine the functionality of the pipes in
meeting their design criteria.  USEPA has defined "condition assessment" as the collection of data and
information through the direct inspection, observation,  and investigation and in-direct monitoring and
reporting,  and the  analysis of the data and information to make a determination of the structural,
operational and performance  status of capital infrastructure assets (USEPA, 2007).
The type of pipe defect varies depending on the pipe material and pipe diameter, as discussed in Section
3.2. The most prevalent defects are as follows: cracks/broken pipe, root intrusion, sediment, grease
build-up, off-set joints, corrosion, manhole frame and cover leaks, and pipe sags.
Pipe failure includes collapse, which may cause extensive property damage and/or discharge of untreated
sewage, severe hydraulic restrictions, and severe decrease in hydraulic capacity. Other less severe  pipe
conditions could also be  considered "failure" depending on the performance standards set for the system.
The term inspection technologies in this white paper refers to the various methods used for detecting pipe
defects, structural  and operational condition, and environmental conditions that could potentially impact
pipe condition. These technologies, discussed in  Section 4.0, have varying abilities for detecting and
quantifying specific types of pipe defects. Inspection technologies may have limited applications
depending on pipe material and/or pipe diameter. A robust condition assessment method would likely
include a variety of inspection technologies, based on the specific characteristics of a utility's sewer
network.


1.4    Critical Gaps in Inspection Technologies and Condition Assessment

A previous research project (Thomson et al., 2004) surveyed large wastewater utility districts to
determine critical  gaps in condition assessment of gravity pipelines and force mains. The survey found
that 100% of the 31  survey respondents relied almost exclusively on CCTV as the primary means to
inspect pipes.  The general limitations of current CCTV technology were the focus of the identification of
critical gaps. There were also several respondents who expressed concerns with the inability to measure
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the structural integrity of the pipe wall and the inability to measure crown corrosion of concrete pipe and
internal corrosion for ferrous pipes.

1.4.1    Gravity Line Inspection

The majority of sewer pipeline inspection activities performed by utilities involve gravity pipelines.  In
the 2004 utility survey (Thomson et al. 2004), critical gaps for inspection technologies for gravity lines
were defined as follows:
        •  The needs for improvements to CCTV - higher resolution cameras with better lighting;
           improvements in crawler technology to negotiate obstructions, grease, offset-joints; and
           cameras for inspection of laterals.
        •  Ability to monitor in surcharged (i.e., flooded) conditions.
        •  Inability to obtain information on pipe wall thickness.
        •  Inability to measure slope.
        •  Inability to locate manholes1.
        •  Inability to locate soil voids above or below a pipe segment.
        •  Inability to quantify corrosion (e.g.,  internal, external).

1.4.2    Pressure Line/Force Main Inspection

Inspection of force mains is currently limited to pipelines that are taken out of service.  For this reason,
force mains are infrequently inspected by utilities, primarily because of the inability to take the line out of
service without costly by-pass pumping. Other critical gaps in inspection offeree mains include the
limited number of inspection technologies suitable for use in force mains; and the inability to determine
wall thickness, cracking, and pitting with  currently available inspection technologies (Thomson et al.
2004).

1.4.3    Condition Assessment Protocols

Based on a survey of twenty-four Canadian sewer agencies using condition assessment protocols,
Rahman and Vanier (2004) identified the  lack of consistent, standard condition assessment protocols as a
critical gap. The survey results showed 68% of the respondents used a protocol based on that of the
National Water Research Council. The biggest gaps identified were systematic collection of data and use
of formal risk assessment methods to prioritize resources for maintenance and rehabilitation activities.
Research has focused on the use of models to standardize the risk-based decision-making process.


1.5     Research Questions

The following key research questions relating to sewer inspection and condition assessment have emerged
from EPA research (USEPA, 2007). These questions reflect critical gaps in our knowledge of the
performance of innovative inspection technologies, our understanding of proven condition assessment
techniques, and our ability to diagnose and predict infrastructure failures.
        •  Can emerging and innovative inspection technologies be identified and demonstrated in field
           settings to improve our understanding of their cost-effectiveness, technical performance, and
           reliability?
1 Other sources indicate that manholes can be located via CCTV inspection.  CCTV crawlers can be equipped with
radio transponders to aid in manhole location.
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Can advances in remote monitoring and wireless technologies be applied to reduce confined-
space entry requirements for sewer system inspection and investigation?
What measurements or operational data can be used to determine and track the condition of
assets over time?
Can standard technical guidelines, uniform data requirements, and indicators be developed
for condition assessment of sewers and non-sewer assets, including manholes, service
laterals, and pipe joints?
Can technical guidance be developed for establishing an overall wastewater infrastructure
inspection program, including inspection prioritization, inspection frequency, inspection type
(physical vs. visual, maintenance vs. structural), inspection by asset type, and inspection cost-
effectiveness?
How can a municipality determine the impact of deteriorating collection systems on their
financial budgets?
Can infrastructure failure mechanisms be better characterized to improve risk assessment
models?
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                               2.0    Condition Assessment

Condition assessment has gained considerable attention in recent years amongst municipalities and utility
districts as a component of an asset management program. It can be used to prioritize infrastructure
projects based on relative risk, thereby easing the financial burden on wastewater utilities and their
customers. WERF estimates that wastewater utility purveyors spend approximately $4.2 billion annually
to rehabilitate sanitary pipelines.  Local and state governments are required to tabulate the value of their
public assets (i.e., buildings, roads, utilities, etc.) to support the development of a unified cost accounting
system, per the Governmental Accounting Standards Board Bulletin 34. This program requires detailed
financial accounting of all assets, however, the level of detail to which it is implemented can vary from
city to city. Condition assessment can also assist utilities in implementing USEPA's proposed guidance
for evaluating the Capacity, Management, Operation, and Maintenance (CMOM) program for sanitary
sewer collection systems (USEPA, 2005). The CMOM program requires a municipality that operates a
sanitary sewer system to provide adequate conveyance capacity for all parts of the system and to take all
feasible steps to stop and mitigate the impacts of sanitary sewer overflows.

A variety of processes have been developed for performing condition assessments, ranging from simple to
complex.  They generally follow a similar progression of steps: setting objectives for the condition
assessment, identification of assets and available data, asset inspection, data analysis, and decision
making.  Specific condition assessment processes are described in the WERF publication "Condition
Assessment Strategies and Protocols for Water and Wastewater Utilities" (Marlow et al., 2007) and in the
National Research Council's "Guidelines for Condition Assessment and Rehabilitation of Large Sewers"
(McDonald and Zhao, 2001).  Figure 2-1 illustrates the steps in the condition assessment process.
                                       Inventory database
                                       Impact assessment
                                          Prioritization
                        Frequency of
                        next inspection
                         Rehabilitation
Inspection


Condition
Assessment
   Source: McDonald and Zhao, 2001
                                      Decision- making on
                                      rehabilitation actions
                                Figure 2-1: Condition Assessment
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2.1    Program Development

The development of a condition assessment program must first consider the program drivers and
objectives. The drivers may include regulatory compliance, operation and maintenance efficiency, risk
management, and/or financial budgeting forecast. Often, the primary driver for wastewater utilities is
investigation of sources of infiltration/inflow (I/I) that would require a system-wide condition assessment
program.  Other utilities are more concerned with identifying high risk pipes for which a catastrophic
failure could lead to extensive service disruptions and environmental damage.  A risk-based condition
assessment program would focus on specific pipes that present these types of risk.

Objectives for performing the condition assessment should be explicitly stated, so that the program's
effectiveness can be evaluated. The objectives will also  establish how the results of the condition
assessment will be used in the decision making process,  the final step of condition assessment.  Key
performance indicators (KPIs), metrics used to determine the utility's progress to defined goals, would be
defined at this step. Objectives for performing a condition assessment could be to understand the
structural condition, performance, and/or progression of deterioration (i.e. remaining service life) of the
asset.

The costs of conducting condition assessment must be documented and compared to the anticipated
benefits in order to justify the program.  The costs are typically easier to quantify but should include both
the direct costs of inspection and the indirect costs to the utility and other parties of carrying out the
inspection work and collecting and analyzing the data. The benefits are more difficult to quantify and
derive mainly from the reduction in the risk of failure (likelihood times consequences of failure) and from
the knowledge that allows maintenance, rehabilitation and replacement to be carried out on the most cost
effective schedule. More specifically, the costs of condition assessment include:
       •    Equipment and labor costs to conduct field inspections including excavation, traffic control,
            road surface restoration, monitoring  equipment and data collection.
       •    Labor costs before and after field work for planning, data analysis and reporting.
       •    Cost of service  disruptions due to inspection work.

Specific benefits of a condition assessment program may include:
       •    Avoided emergency repair costs.
       •    Avoided costs of extended service disruptions due to a catastrophic failure.
       •    Avoided restoration costs due to environmental and property damage from a catastrophic
            failure.
       •    Avoided public health costs (i.e. injury, death, disease transmission) from  catastrophic
            failure.
       •    Improved planning and prioritization of rehabilitation  and replacement projects due to
            condition assessment information and improved estimates of service life.
       •    Avoided costs of premature pipe replacement or rehabilitation.

Comparing the costs to benefits for gravity sewers and force mains, it has been reported (Thomson 2008)
that:
       •    The cost of inspection of gravity sewers is typically low with respect to the value of the asset
            (e.g. the cost of inspection of a 12-in diameter sewer at 13-ft depth is less than 1% of the asset
            value) and the proportion decreases with increasing depth and diameter of sewer.
       •    The benefits from inspection of gravity  sewers are likely to exceed costs for all but small
            diameter sewers at shallow depths.
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        •   The cost of inspection of force mains is high with indirect costs often exceeding the direct
           costs of inspection (emptying the line, providing temporary bypass, accessing the line).
        •   The monetary benefits of inspection may be less than the cost of inspection for smaller lines
           in less populated areas (fail and fix approach may be chosen) although this ratio may change
           in environmentally sensitive areas. The benefits increase greatly for larger diameter force
           mains  and urban areas due to the increased risk of major consequences.

When performing condition assessment, it is essential to compile an inventory of assets and existing
system data (i.e. pipe material, size, age, maintenance history, inspection records). The utility should
understand the content and form of existing data, and should identify data gaps at this step. System maps
and geographic information system (GIS) databases are good information resources. Inspection and
testing records may include I/I studies: flow data, smoke testing, flow isolation studies, and/or dye tracer
studies. Failure data from within the system or from research on similar conditions (e.g., soil bedding
type, material, age) in utility districts can be used to define risk of failure. Data gaps identified  in this
step are used to plan the inspection program.

A key difficulty in developing a rational inspection, condition assessment, and asset management
program is that some of the most critical elements of the sewer infrastructure are the most difficult and
expensive to inspect. For example, large diameter sewers have continuous and high levels of flow that
make bypassing the sewer difficult or impossible. They may contain large debris that hinder inspections
unless the pipes are cleaned first, and they may not have been inspected for decades. Similar conditions
exist for force mains in terms of the consequences of failure vs. the ability to inspect.


2.2     Asset Inspection

The primary purpose of an inspection is to define the current condition of an asset, in order to detect and
evaluate the progression of deterioration and to make informed decisions  on asset management. A well
developed inspection plan will maximize the value of the program, while  minimizing the cost of
inspection. A detailed work plan and quality assurance project plan should also be established at this step
to outline how the  proposed inspection program would meet the program  objectives. The inspection plan
should focus on what assets to inspect, when they should be inspected, and what technologies will be used
for inspection.  Ideally, an inspection would occur at a point prior to failure where an intervention could
effectively renew the asset. For a buried pipeline, there is limited ability to obtain a warning indicator as
to the appropriate time and location to perform an inspection. It is this unknown state that is the inherent
risk in managing buried assets.

2.2.1    Selection of Assets for Inspection

It may be considered cost prohibitive to inspect every linear foot of a wastewater collection system
especially when confronting the need to inspect a large system with little prior inspection history. It is for
this reason that condition assessment programs generally use a planned approach to focus on high
consequence/high risk pipes  or to utilize statistical sampling to select assets for inspection. Decisions on
which assets to inspect should be related to the objectives and KPIs defined in the program development
phase of the condition assessment process. For example, if the objective or KPI is to reduce SSOs, then a
utility may focus on service lateral, which are often a large source of I/I. If the objective or KPI is to
reduce risk of failure of high consequence pipes, then a utility may focus on pipes with higher impact and
probability of failure, and not inspect service laterals, as they are not high risk or high consequence.
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2.2.2   Prioritization of Assets

Two models for prioritizing assets for inspection are described below:

       •   The National Research Council's approach (McDonald and Zhao, 2001) utilizes an "impact
           assessment" to prioritize assets for inspection.  Impact assessment is a weighted average of
           six separate impact factors:  location, soil support, size, depth, sewer function, and seismic
           factors. Impact assessment can then be directly calculated in a uniform approach based on a
           weighted average.
       •   SCRAPS (Sewer Cataloging, Retrieval, and Prioritization System) is based on the general
           approach of defining risk factors based on consequence of failure and likelihood of failure
           (Merrill et al., 2004). The term "Consequence of Failure" is defined as the impact of a failure
           in terms of repair cost, disruption to the public and economy, impairment of system
           operation, regulatory compliance, public health and safety, and damages to the environment.
           The same terminology can also be applied to the decision making process used in applying
           condition assessment to asset management. The impact of a failure must be understood and
           quantified. If the impact can be quantified in dollars, then it can be compared to both the cost
           of condition assessment and the cost of replacement and/or rehabilitation.

2.2.3   Asset Inspection

The type of inspection performed depends on the objective of the condition assessment program. The
selected inspection technique needs to be consistent with the type of asset to be inspected and provide the
information and data required to support decision making.  Flow monitoring is usually utilized when
conducting I/I studies, to evaluate hydraulic capacity and determine hydraulic restrictions. CCTV is the
most commonly used method of inspecting sewers for structural defects; however, there are a variety of
technologies available for this type of inspection; these technologies are discussed in-depth in Section 4.0.
A detailed work plan and quality assurance project plan should be established; these documents ideally
would outline how the proposed inspection program would meet the program objectives.


2.3    Data Management

A successful condition assessment program as part of an asset management program requires that the data
collected are organized, analyzed, and maintained in a database system.  This important step allows a
utility to develop an understanding of trends. There are three general approaches to database management
that have varying degrees of cost and complexity but all of which use commercially available software:

       1.  Software specifically designed for condition assessment and asset management.
       2.  Database software that is not specifically designed for condition assessment.
       3.  Spreadsheet software.

2.3.1   Con dition Assessment/Asset Man agement Software

There are numerous commercially available data management programs for condition assessment that
range in level of complexity and cost. The primary component is a database to store defect coding on
pipe segments both spatially and overtime. The commercially available systems can also incorporate
additional elements such as cost accounting, develop work orders for maintenance calls, and order parts to
maintain required spare parts.  Another useful feature is the incorporation of GIS functionality into the
system. The GIS component highlights the geo-spatial distribution of the data, and can provide a very
effective tool for the utility to plan subsequent inspections and/or rehabilitation activities. The benefit of
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the commercially available programs is that they are designed specifically for the intended purpose.
However, the cost of system maintenance can be significant, as can licensing costs, depending upon
system complexity.

Another type of commercially available software is designed to summarize the results of a CCTV
inspection and the resulting defect code  data.  This has become standard practice in the industry. The
National Association of Sewer Service Companies (NASSCO) licenses software programs to be
consistent using the PACP and Manhole Assessment Certification Program (MACP) rating systems,
which are discussed in Section 2.4.2.  The certification programs allow commercial providers to submit
their pipe assessment software for evaluation and certification to ensure that their software adheres to
NASSCO standards.  It is important to verify the software has been approved to decrease the set-up time
required to enter ranking and coding information. Pipeline inspection software is used simultaneously
with pipeline inspection hardware to accurately document the status of sewer pipe, storm drains, or water
pipelines.  The software gives access to text data, video, and still photos all of which help the user identify
the condition of the pipe and precisely complete a pipeline inspection. Defects can be quickly categorized
by location, type, and severity. The software compiles this data into a searchable database which can be
distributed into printed reports.

2.3.2  General Database Management Software

Utilization of commercially available  database software requires a utility to design a database specific to
their needs.  The benefit would be the reduced initial licensing cost of the software. Most utilities would
have database software  as part of their professional software packages licensed for their operating system.
Another benefit is that it may cost less to maintain than the condition assessment software described
above. A drawback to this approach is the significant up-front work and required expertise to design a
database system for the intended purpose.

2.3.3  Spreadsh eet Software

Spreadsheet software is the least costly of the three systems; however, it also has the most limitations.
This type of software is readily available and likely exists at each of the utilities. A simple yet effective
system can be designed to collect and store data.  However, spreadsheets are a flat file system and are
very limited in usefulness as the database expands. It can become overly cumbersome if multiple spread
sheets are required.


2.4    Data Analysis

The data resulting from inspection may quantify the level of service and/or structural defects. It does not,
however, provide any ability to reduce risk or define the significance of the finding. The follow-up step is
to process and analyze the inspection data. There are two general analysis methods used, based on the
type of inspection performed.  If flow monitoring was employed as the inspection technology, an analysis
of hydraulic capacity is performed, using hydraulic modeling techniques. If an inspection of structural
defects utilizing CCTV or one of the other non-destructive technologies was performed, analysis is
generally performed by coding defects in accordance with one of the various methods available, such as
the Water Research Centre (WRc)'s system or NASCCO's PACP and MACP programs

2.4.1  Hydraulic Capacity/Hydraulic Restrictions

Hydraulic capacity is the primary performance measure for a wastewater collection system. Flow data
gathered by flow meters has been used to guide sewer system management for at least three decades.
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Advancements in technology and software have brought a new level of condition assessment information
to utility managers.  The purpose of this section is to discuss the use of flow data as a tool in condition
assessment. A description of improvements in flow meter technology is discussed in Section 4.5.
Historically, flow data have been used in Sewer System Evaluation Survey (SSES) as a screening tool to
prioritize areas for further study. Flow data presented over a period of time are useful in demonstrating
the system impacts due to rainfall or elevated groundwater.  It provides the required information to
calibrate a hydraulic model or conduct I/I studies. The hydraulic model can then be used as a predictive
tool to project overflow and/or surcharged conditions for various design storms.
The following is a list of the most common indirect measurements that allow an operator to assess the
general condition or rate of I/I:
        •   Average Daily Dry Weather Flow includes the average flow from a sewershed, which is
           composed of the wastewater production rate and base infiltration of the system.
        •   Base Wastewater Flow is estimated on the number and type of sewer users, domestic water
           usage records, and predicted diurnal flow variations. It equates to the anticipated flow rate of
           only wastewater in the system.
        •   Groundwater infiltration is determined by subtracting the estimated Base Wastewater Flow
           from the Average Daily Dry Weather Flow.
        •   Capture coefficient or percentage of rainfall that enters the sewer.
        •   Relationship between rainfall and peak flow rate.
The I/I values are valuable for planning purposes, providing  a good indicator of pipe conditions upstream
of a flow meter.  As the sub-areas for which data are collected increase in size, flow data are less useful as
a predictive tool for condition assessment. It does, however, provide the data to quantify groundwater
infiltration and wet weather derived flow for the area tributary to the metering location.

The real value of flow monitoring data of sewers is developing a database on long-term historic trends in
order to determine seasonal variations and impacts of wet weather.  Flow data provide the direct
correlation needed to determine if performance measures are being attained.  Flow data are also useful as
a screening tool to determine problems areas of a system that require further study by other means.
The traditional method of viewing flow data is hydrographs, which reveal information on condition
upstream of flow meters. Alternatively, flow data can be viewed as scattergraphs, which provide
information on hydraulic conditions downstream, or in the vicinity of, a flow meter. Scattergraphs are
created by plotting  flow depth versus flow velocity data. When flow meters are working correctly, a
normal pipe curve is plotted unless normal open channel flow is not occurring. In these cases, the
scattergraph data can be used to identify such hydraulic restrictions as silt or obstacles, bottlenecks, and
negative grade pipe, as well as surcharged conditions.

2.4.2   Structural Condition

For wastewater collection systems, analysis of inspection data generally involves coding the defects based
on both the type and severity of defects. Structural pipe defects and hydraulic restrictions encountered
during the inspection need to be ranked by severity level based on the potential to negatively impact the
system's hydraulic  capacity.
The WRc, located in the United Kingdom, developed a set of standards to rank the severity of pipe
defects found in an inspection. European authorities adopted these standards as their benchmark pipe
defect coding standard. In 2001, NASSCO developed a set of coding standards based on the WRc system
(NAASCO, 2001).  The NASSCO PACP standards have successfully become the industry standard for
coding pipe defects. NASSCO has also developed the MACP, which is similar to PACP but applies to
manholes  instead of pipelines. NASSCO has training programs to certify and train inspection
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professionals in PACP and MACP. NASSCO has begun work on developing a coding system for service
laterals.
The PACP coding system categorizes defects and features into five sections: continuous defect coding,
structural defect coding, operational and maintenance coding, construction features coding, and
miscellaneous features coding. For each type of defect, the PACP uses a combination of capital letters to
describe the type of defect and a number to rank the severity of the defect. An example is "FL" for a
longitudinal fracture. Defect codes are recorded on a standardized form along with pertinent system data
including defect type, continuous distance of the defect, severity, size, circumferential location (clock
location), joint number, image/video reference number, and comments.
A brief description of the PACP defect coding system is described below:

       •   Continuous Defect Coding:  Continuous defect coding is made up of two separate coding
           classifications.  The first is called "Truly".  Truly continuous defects are defects that run
           along the sewer for a minimum distance of three  ft.  These defects include longitudinal
           fractures and cracks. "Repeated" continuous defect coding defects are continuous defects
           that occur at regular intervals along the pipe. These usually occur at pipe joints and include
           encrustation, open joints, and circumferential fractures. Continuous defect coding can be
           used in conjunction with other types of coding to accurately describe defects on the PACP
           form.

       •   Structural Defect Coding: Structural defect coding is made up of a number of separate
           coding classifications.  This section uses coding to define the type  of defects that are related
           to structural degradation of the pipe due to various reasons.  The coding under structural
           defects are as follows: crack (C), fracture (F), broken (B), hole (H), deformed (D), collapse
           (X), joint (J), surface damage (S), lining failure (LF), weld failure (WF), point repair (PR),
           and brick work (BW).  Under each of these subtitles there are also other letters to further
           define the type of defect.  For example: HSV is for a hole with visible soil.

       •   Operational and Maintenance Defect Coding:  This section uses coding to define the type
           of defects that are related to lack of maintenance on  the pipe system. Operational and
           maintenance defect coding is made up  of a number of separate coding classifications as
           follows: deposits (D), roots (R), infiltration (I), obstacles (OB), and vermin (V).  Under each
           of these subtitles there are also other letters to further define the type of defect. For example:
           VR designates that there are vermin, specifically, rats in the pipe.

       •   Construction Features Coding: This section uses coding to define construction features
           located in or around the pipe system. Construction features  coding is made up of a number of
           separate coding classifications as follows: tap (T), intruding seal material (IS), line (L), and
           access  point (A).  Under each of these subtitles there are also other letters to further define the
           type of defect. For example: AMH designates that there is an access point in the line that is a
           manhole.

       •   Miscellaneous Features  Coding: Miscellaneous features coding is made up of a number of
           separate subcoding classifications. This section uses coding to define miscellaneous (M)
           features in the pipe system. Under this subtitle there are also other letters to further define the
           type of defect. For example: MCU designates that the camera is underwater.

The PACP uses a numerical grading system to define the severity of pipe defects. Condition grades for
structural defects and operation and maintenance (O&M) defects are assigned based on the risk of further
deterioration or failure.  The numerical system uses numbers  ranging from 1 to 5 with 1 being the best
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and 5 being the worst. The severity ranking considers the immediate defect, risk of failure, and rate of
deterioration.

        •   Grade 5 - Pipe segment has failed or will likely fail within the next five years. Pipe segment
           requires immediate attention.
        •   Grade 4 - Pipe segment has severe defects with the risk of failure within the next five to ten
           years.
        •   Grade 3 - Pipe segment has moderate defects. Deterioration may continue, but not for ten to
           twenty years.
        •   Grade 2 - Pipe segment has minor defects. Pipe is unlikely to fail for at least 20 years.
        •   Grade 1 - Pipe segment has minor defects. Failure is unlikely in the foreseeable future.
Pipe ratings are based on the number of occurrences for each condition grade and are calculated
separately for both structural and O&M defects for each pipe segment. Each pipe segment will be
assigned a segment grade based on the number of occurrences of each graded defect. The graded defect
is multiplied by the number of occurrences, and this equals the segment grade. The overall pipe rating is
calculated by adding all of the segment grades per pipeline.  The structural defects are  added separately
from the O&M grades, so each pipeline receives two separate grades.
The PACP also uses a quick grading system, which is a shorthand method of expressing the number of
occurrences for the 2 highest grade levels. The quick grading system uses four characters:
        1.  The first character is the highest severity grade occurring along the pipe length.
        2.  The second character is the total number of occurrences of the highest severity grade. If the
           total number exceeds 9, then alphabetic characters are used as follows: 10 to 14-A, 15-19-B,
           20 to 24-C and so on.
        3.  The third character is the next highest severity grade occurring along the pipe length.
        4.  The fourth character is the total number of the second highest severity grade occurrences,
           which is formatted the same way as the second character.
For example, a code of 3224 would equate to two grade 3 defects and four grade 2 defects in a pipe
segment. This also shows that no grade 4 or 5 defects were found.  The quick grading system allows the
pipe defects to be summarized in an efficient manner. As with the longhand method, structural defects
are graded separately from O&M defects.


2.5     Decision Making

Decision making for condition assessment of a wastewater collection system entails understanding the
possible risks and determining at what point a utility should intervene to avoid a failed condition with an
unacceptable cost and/or consequence. It is  important to note that condition assessment alone does not
provide any benefit in risk reduction.  The follow-up decision making process that leads to prioritization
ranking and rehabilitation ranking followed by action to fix problems and upgrade the  system is what
leads to risk reduction.
The purpose of this section is to highlight and summarize the decision making process, the final step in
the condition assessment process.  In addition to inspection data, the utility requires supplemental data on
long-term asset performance to aid in the decision making process.
Marlow et al. (2007) posed the following questions that need to be addressed to provide the required
information for decision making:

        •   What are the consequences of asset failure?
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        •   What are the costs to replace/rehabilitate the assets?
        •   What alternatives exist, given the results of the condition and performance assessment (e.g.,
           replacement, deferment, rehabilitation, non-structural maintenance)?

Important definitions to consider are failed condition and service life.  The American Concrete Institute
defines service life as the period of time following installation during which all properties exceed
minimum accepted standards when routinely maintained.

        •   Technical service life - period of time until an unacceptable condition is reached.
        •   Functional service life - period of time until the system element no longer provides
           functional service.
        •   Economic service life - period of time until it becomes economically more effective to
           replace or rehab than to continue to operate in its current condition.

The objective for the decision making model is to understand risk and to determine when to intervene to
avoid unacceptable consequences (e.g., economic, socio-economic, environmental).  However, it is not
possible to have a robust decision making model without obtaining sufficient condition data to track pipe
deterioration and to understand the  pipe or system failure modes.

In general terms, decisions on pipe  rehabilitation/replacement can be  made based on one or more of the
following: engineering calculations, probability of failure, and remaining life estimation.

        •   Engineering Calculations:  Inspection data are interpreted deterministically. An example
           would be to calculate structural condition of a pipe segment directly based on measured
           minimum wall thickness, actual loading conditions, and existing soil bedding.  A second
           example of this methodology is the calculation of hydraulic capacity.  Flow data can provide
           direct measurement of actual flow conditions; and then be interpolated using a hydraulic
           model to calculate hydraulic capacity of a pipe segment under current or projected conditions.
           Both of these examples illustrate a direct calculation of the condition or performance of the
           pipe segment.  If it does not meet the required design conditions or performance conditions,
           then replacement or rehabilitation is required.

        •   Probability of Failure: This type of output would ideally provide a direct forecast of pipe
           deterioration over time. If a utility have the data to support this type of forecast, then an
           intervention could be implemented before an unacceptable level of service occurred.  In
           practice, it is difficult and potentially costly to directly determine the probability of failure.
           However, the American Concrete Institute (2000) did reference studies and models to predict
           failure rate in reinforced concrete pipe.  Regression forecasts and models were developed to
           predict failure of reinforced concrete pipe (RCP) based on chloride concentrations, extent of
           spalling and mechanical loading  conditions, and sulfate concentration. Repeated data
           collection and analysis  over time are required to obtain the decay curves based on the
           different paths to failure and the system or environmental conditions that exacerbate each
           failure mode.

        •   Remaining Life Estimation:  Remaining life estimation is commonly used to characterize
           condition of buried assets. Remaining life is defined as the duration of time until an
           unacceptable condition exists or an asset no longer meets its primary function. Standard
           coding systems are used to define condition and performance. NASSCO's PACP system,
           discussed in Section 2.4.2, has become the standard to follow in the United States for
           wastewater pipe systems.
                                            Page 2-14

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A variety of decision making models have been developed for sewer assets. WERF is developing a web-
based model based on remaining economic life of water and wastewater pipes.  T-WARP is a software
program that uses fuzzy logic to analyze the possibilities of pipe failure. The European Union's
Computer-Aided Rehabilitation Program for Sewers (CARE-S) is a software program that supports
efficiency in rehabilitation decisions. McDonald and Zhao (2001) propose a matrix approach for decision
making based on asset condition grades and an impact assessment rating as summarized in Table 2-1.
The term impact assessment is defined by the authors as a weighted average of six separate impact
factors: location,  soil support,  size, depth, sewer function, and seismic factors.

Table 2-1: Condition Assessment Matrix
Asset condition
grade*
5
4
3
2
Otol
Implication of asset
condition
Failed or imminent failure
Condition poor, high risk of
structural failure
Condition poor, moderate
structural risk
Fair condition, minimal
structural risk
Good condition
Impact assessment
Ito5
5
Ito4
4 to 5
Ito3
5
Ito4
5
Ito4
Action
Immediate
Immediate
High
Medium
Low
Medium
Low
Not required
Inspection
frequency
NA
NA
2 to 6 years
3 yrs
5 to 10 years
5 years
10 to 15 years
10 years
15 to 25 years
 * Condition grade is based on WRc coding system (Manual of Sewer Condition Assessment, WRc 2003).

 NA - Not Applicable
Source: McDonald and Zhao, 2001
                                            Page 2-15

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             3.0    Dynamics of Wastewater Collection System Failure

In conducting condition assessment, it is important to understand the dynamics of pipe failure including
the level, type, and severity of a failure mechanism. Failure modes can include sudden, catastrophic
collapse of a pipe or restricted hydraulic capacity. The purpose of condition assessment is to detect pipe
defects which indicate the likelihood of pipe failure, as well as to assess the collection system's
performance. This section discusses the mechanisms of pipe failure, the various types of pipe defects,
and the relationship between the condition of a pipe and its performance. It is important to understand
that pipe failure and defects are highly dependent upon the pipe material, diameter, and type of sewer
(e.g. force main, gravity line).


3.1    Failure Mechanisms

Pipe failures can be grouped into three general categories according to the cause of failure: hydraulic
restrictions (e.g. blockage), hydraulic  capacity, and structural condition. The following sections provide
additional details on these failure mechanisms.

3.1.1  Hydraulic Restrictions

The primary function of a wastewater collection system is to convey wastewater; therefore, hydraulic
capacity and factors that limit it are of paramount concern. Hydraulic restrictions are the most prevalent
condition encountered in wastewater collection systems.  The characteristics of untreated wastewater are
such that accumulation of sediment, grease, and rags is a constant maintenance item.  There are situations
in larger diameter sewers, especially combined sewers, when large items create obstructions and rapid
hydraulic restrictions.  This can lead to street and basement flooding.
Standards used for hydraulic design mandate minimum slopes for various pipe diameters to achieve
scouring velocities that minimize debris accumulation. However, there are many external conditions that
encourage debris accumulation (e.g. root intrusion, grease, pipe sags).
Blockages are easily detected by visual inspection. The direct cause of a blockage sometimes is not
evident. For most conditions, the failure rate is slow over time.  A standard maintenance program for
cleaning and flushing sewers is typically adequate to control blockages.  The types of defects that fall
within the category of hydraulic restrictions are as follows:  root intrusion, sediment accumulation, and
grease build-up.  It should be noted that off-set joints and pipe sags can directly impact pipe flow thereby
creating low velocity conditions that are conducive to  solids deposition.

3.1.2  Hydraulic Capacity

Failure due to hydraulic capacity is defined as a pipe segment not having adequate, available  capacity for
the designed conditions. The failure condition may be caused by excessive I/I, pipe deformation, and/or
inadequate slope.
I/I have a direct impact on the capacity available to convey wastewater.  The groundwater and storm
water enter the collection system through direct connections or indirectly via cracks and defects. Zero I/I
is not a realistic design objective. The hydraulic design of new sewers considers an anticipated level of
I/I in determining pipe size.

Pipe deformation and inadequate slope directly impact the hydraulic capacity of the pipe.  Flow can be
calculated based on the Manning's equation for normal flow conditions:
                                            Page 3-16

 image: 






Q = l/n*A*Rh2/3*S1/2
Whereas
        Q = Flow2 (volume per time).
        A = Cross-sectional flow area (area).
        n = Manning's roughness coefficient.
        Rh = Hydraulic radius (length).
        S = Pipe slope.
The mathematical relationship of change in area due to pipe deformation or inadequate slope is self-
evident.  A decrease in flow area and/or pipe slope will result in a proportional decrease in flow capacity.
Failure due to hydraulic capacity is often a sign of other types of defects such as structural defects.  Major
sources of I/I can be cracks, broken pipes, leaks from manhole frames and covers, and off-set joints. Pipe
sags and areas of inadequate pipe slope can be due to loss of pipe bedding or inadequate construction
controls.

3.1.3    Structural Failure

Structural failure is caused by defects of the pipe wall and/or the soil envelope used to support the pipe.
In general, the types of defects that are associated with structural failure include cracks, misaligned or off-
set joints, pipe deflection, cracked manhole frames and covers, and internal and external corrosion.
Internal corrosion is caused by hydrogen sulfide formation, and external corrosion is due to soil
corrosivity.
The pipe is supported by a soil envelope that consists of the soil bedding and the cover soil. The soil
bedding acts as the foundation for the pipe and distributes the vertical load around the exterior of the pipe
wall.  The pipe is subjected to live loads and earth loads. The goal of the bedding design is to transmit
this load to the bedding and avoid point loads on the pipe. Loss of bedding can result in the pipe bridging
areas  of reduced bedding. This can lead to pipe deflection, pipe deformation, and longitudinal cracking.
Increased traffic load or loss of soil cover is another cause of structural failure.
The type and degree of failure differ by pipe material. Some pipe material (e.g. PCCP) is susceptible to
sudden failure while others fail gradually and are easily detected by visual inspections. Typical failure
modes for various types of pipe material used in sewer collection systems include:
        •  Ferrous Pipe (Ductile Iron, Cast Iron, Steel) - The primary failure mode for metal pipes is
           internal or external corrosion, which leads to breaks or holes in the pipe wall.  Cast iron in
           particular is brittle, making these pipes prone to cracking. Large diameter steel pipes are
           susceptible to collapse as well as corrosion.
        •  Concrete Pipe (RCP, PCCP) - Corrosion is often a major factor in the structural failure of
           concrete pipe.  RCP typically fails after the interior surface of the pipe wall has deteriorated
           to such a degree that the reinforcing steel is exposed.  As the reinforcing steel corrodes, it
           swells, beginning to break up the surrounding concrete and causing failure. PCCP has  a
           distinctive failure mechanism as failure occurs when the pre-stressed wires break, generally
           as a result of corrosion or direct physical damage to the pipe.
        •  Ceramic-based pipe (Brick, Vitrified Clay Pipe (VCP)) - Brick pipes generally fail by
           collapse, often caused by weakened mortar. VCP fails when external loads create cracks in
! Please note a factor of 1.49 is used when utilizing British Units.


                                            Page 3-17

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           the material. Failure is often exacerbated by the loss of surrounding soil into the pipe after
           initial fracture leading to void formation and loss of soil support to the pipe.
        •   Plastic Pipe (Polyvinyl Chloride (PVC), High-density Polyethylene (HOPE)) - The
           primary failure mode  of plastic pipe is environmental stress cracking, which occurs from
           stress developed in a deflected pipe or due to slow crack growth, a phenomenon that occurs
           when a pipe is subjected to long duration tensile stress. Leaking joints can also contribute to
           plastic pipe failure.


3.2     Pipe Defects

Sewer defects are generally categorized as  service or structural. Structural defects include cracks,
fractures, breaks, deformations, collapses, joint displacements, and open joints.  Service defects include
tree roots, obstructions, debris, and encrustation.  Pipe defects can also be classified by whether they are
defects of the internal pipe surface, a pipe wall defect, a leak, or an alignment defect.  Thomson et al.
(2004) classify defects  as internal  pipe surface (sediment, debris, and roots), pipe wall (pipe sags and
deflections, pits and voids, corrosion and metal loss, off-set joints, pipe cracks, broken pre-stressed wires,
wall thickness, service  connections and deteriorated insulation), leakage, and pipe support (bedding
condition and voids).

The most prevalent defects in wastewater collection systems are cracks/broken pipe, root intrusion,
sediment, grease build-up, off-set joints, corrosion,  frame and cover leaks, and pipe sags. However, pipe
defects vary with the pipe material and pipe diameter. Because gravity lines and force mains are
generally constructed of different materials, they are susceptible to different types of defects.
Gravity pipes are usually constructed of VCP or PVC which are prone to grease build-up and joint
misalignment/leakage.  However,  VCP is likely to experience cracks/breaks and root intrusion, whereas
PVC is more likely to have excessive deflection, grade and/or alignment issues, and lateral connection
defects.

Unlike gravity pipes, most force mains are  constructed of ferrous materials (i.e., welded steel, ductile
iron, or cast iron) or plastic  (PVC, HDPE). Large diameter force mains have also been constructed of
PCCP. While ferrous pipes tend to experience defects similar to VCP and PVC, internal and external
corrosion are the primary defects.  Table 3-1 provides a summary of the most common pipe defects by
pipe material from a recent utility  survey (Thomson et al., 2004).
                                            Page 3-18

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Table 3-1: Most Common Pipe Defects Identified
Defect
Internal pipe surface
Root intrusion
Grease build-up
Pipe wall condition
Cracks/ broken pipe
Internal corrosion
External corrosion
Leakage
General
Joint leakage
Leaking laterals
Alignment/grade
Alignment
Joint misalignment
Excessive deflection
Grade
Concrete
Concrete pipe

•
•

•



•




•


Asbestos
cement

•
•

•
•


•




•


U PH
u u
a. U

•
•


•
•


•






Ferrous
a 1
.§s
•£ "g
a S
U •§

•
•


•
•

•

•

•
•


1
<si

•



•
•


•




•

Ceramic
a.
U

•
•

•



•




•


^
_u
CO

•
•













Plastic
U
I


•





•



•

•
•
HDPE

•
•







•

•

•
•
Other 1 234
 1 - Liner separation, weld failure
 2 - Missing bricks, soft mortar, vertical deflection, collapse
3 - Lateral connections
4 - Pressure capacity (force mains only)
Source: Thomson et al. (2004). Reprinted with permission from WERF.

3.3     Correlations between Assessed Conditions and Performance Measures

The measure of performance for a wastewater collection system can be based on four critical areas:
service level, regulatory compliance, public health and safety, and environmental protection (Fleury and
Warner, 2007). The subsections below describe how these performance measures can be correlated to
pipe condition.
        •   Service Level: Wastewater utilities strive to provide continuous, efficient service for their
           customers.  Pipe conditions that affect service level include defects or conditions that affect
           the available hydraulic capacity to convey current and future planned wastewater flows.
           Excess hydraulic capacity in a newly constructed piping system can diminish over time due
           to many types of defects: corrosion, I/I, sediment accumulation, pipe deflections,  and cross-
           connections.

        •   Regulatory Compliance: Wastewater utilities must comply with existing regulations.  The
           Clean Water Act (CWA) prohibits discharges of pollutants to waters of the U.S., unless
           authorized by a National Pollutant Discharge Elimination System permit. Unpermitted
           discharges from the sanitary sewer system constitute a violation of the CWA.  Non-
           compliance with the SSO regulations, specifically the CMOM provisions, will result in
           enforcement actions including mandated O&M programs and fines.  Pipe conditions that
           affect regulatory compliance may include defects or conditions that cause sewage overflows
           or back-ups.
                                            Page 3-19

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        •   Public Health and Safety: Wastewater utilities protect public health and safety by
           minimizing conditions where the public can be exposed to untreated sewage such as receiving
           waters used for drinking water sources, fishing, and/or contact recreation such as swimming.
           Pipe conditions that affect protection of public health include defects or conditions that cause
           sewage overflows, back-ups or catastrophic pipe failure.

        •   Environmental Protection:  Pipe failure may cause extensive property damage and/or
           discharge of untreated sewage.  Failures of large diameter pipes and force mains contribute to
           the formation of sinkholes that may lead to damage and/or disruption to roadways and
           utilities, as well  as the creation of hydraulic restrictions.  Pipe conditions that affect
           environmental protection efforts are similar to those listed above—defects or conditions that
           cause sewage overflows, back-ups, or catastrophic pipe failure.

Utilities use pipe condition  information to assess how well they are meeting each of these performance
measures and to identify and prioritize system needs. The goal is to provide the best possible service in a
cost-effective manner.  Utilities need to know what is an acceptable level of performance that can provide
regulatory  compliance, environmentally acceptable  performance, and operational  effectiveness at the
lowest possible life cycle cost? Inspection and condition assessment provide key information for helping
the utility address these questions and balance system needs and costs.
                                            Page 3-20

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                             4.0    Inspection Technologies
Inspection technologies and their use in condition assessment for wastewater collection systems are
presented in this section. Each technology is briefly described, and commercially available and emerging
products utilizing the technology are discussed. Table 4-1 provides a summary of typical applications for
each technology.
Table 4-1:  Inspection Technology Overview
Technology
Camera
Acoustic
Electrical/
electromagnetic
•_
o>
5«
cS
-J
Innovative technologies
Digital cameras
Zoom cameras
Push-camera
In-line leak detectors
Acoustic monitoring
systems
Sonar/ultrasonic
Electrical leak location
Remote field eddy current
Magnetic flux leakage
Laser
profiling
Gamma-gamma logging
Ground penetrating radar
Infrared thermograph
Micro-deflection
Impact echo/SASW
Sewer type
^»
-*^
1
O
•
•

•

•
•
•
•
•
•
•
•
•
•
Force main



•
•
•
•
•
•
•
•
•
•


Lateral


•



•
•
•

•
•
•


Pipe material
Any
Any
Any
Any
PCCP
Any
Non-
ferrous
Ferrous,
PCCP
Ferrous
Any
Concrete
Any
Any
Brick
Brick/
Concrete
Pipe diameter
6-in.-
60-in.
>6-in.
1-in.-
12-in.
>4-in.
>18-in.
>2-in.
>3-in.
>2-in.
2-in.-
56-in.
4-in.-
160-in.
Not yet
defined
Not yet
defined
Not yet
defined
Not yet
defined
>6-ft.
Defects detected
Internal
condition
•
•
•


•



•





Pipe wall
•
•
•

•
•

•
•
•



•
•
&
3
CS
X
•
•
•
•


•
•



•
•


•c
0
a.
1
0)
S










•
•
•
•

                                           Page 4-21

 image: 






4.1    Camera Inspection

CCTV inspection is a very effective method of evaluating and creating a permanent video record of
underground pipe conditions. The visual inspection of sanitary sewer lines enables a CCTV operator to
locate and identify  specific defects that contribute to the infiltration of groundwater into the collection
system and exfiltration of sewage into the substrate surrounding a pipeline.  This is a well established and
common industry method for pipeline assessment.  In a recent survey report (Thomson et al., 2004),
100% of survey respondents from large wastewater utility districts relied on CCTV as their primary
method of collection system inspections; hence, it is not surprising that the critical gaps identified in this
survey parallel the  limitations of CCTV inspection. CCTV provides a means to inspect a pipeline that is
either too small or hazardous for direct human entry inspection. The primary disadvantages to the
technology are that it only provides a view of the pipe surface above the waterline and does not provide
any structural data  on the pipe wall integrity or a view of the soil envelope supporting the pipe.
The technology and level of ancillary equipment used for CCTV inspection of sewer systems varies
significantly based on the diameter of the line being inspected.  In general, CCTV technology uses a
video camera with  lighting to provide a visual recording of the inside condition of a pipeline.  The means
to convey the camera through the pipeline vary in complexity from simple pushrod cameras (pushcams)
to complex remote  controlled robot crawlers.  The level of optical control on the camera also varies in
complexity. The ability to pan, tilt, and zoom has become the industry standard for sewer inspection
because it allows the operator to gain a full circumferential view of the pipe.
Data obtained from CCTV inspection include:
       •  Evidence of sediment, debris, roots, etc.
       •  Evidence of pipe sags and deflections.
       •  Off-set joints.
       •  Pipe cracks.
       •  Leaks.
       •  Location and condition of service connections.


As noted above, CCTV technology does have limitations due to its ability to only provide a visual
representation of the inside surface of a pipe above the waterline.  Additionally, the quality of defect
identification and pipe condition assessment using CCTV is highly dependent on many factors including
operator interpretation, picture quality, and flow level. In terms of benefits, it is a cost-effective
technology providing the broadest base level of data used in condition assessment. For example, many
technologies exist (as described in later section) that provide data on the structural condition of the pipe
wall, and other technologies exist that can determine the condition of the soil surrounding the pipe.
However, these technologies are unable to provide visual data on leaks, location of service laterals, and
sediment and debris accumulation. It is for this reason that CCTV will remain an important inspection
tool in any condition assessment program for wastewater collection systems.

The following sections present innovative technologies specific to CCTV and its use in condition
assessment for wastewater collection systems. Each technology will be briefly described, noting
manufacturers and/or providers of the technology and typical applications. The technologies described in
this section include:
       •  Zoom Camera Inspection.
       •  Digital Scanning.
       •  Camera Deployment.
                                            Page 4-22

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4.1.1   Zoom Camera Inspection

Like traditional CCTV inspection, zoom camera inspection technology involves the generation of still
imagery and/or recorded video imagery of a pipe. The key difference is that in zoom camera inspection,
the camera mount is stationary. The technology does not require the camera equipment to pass though the
entire length of the pipe segments being inspected. Instead, the camera is mounted either on a truck,
crane, pole, or a tripod.  The equipment is then lowered into a manhole to perform the inspection and the
camera "zooms" down any pipe entering or exiting the manhole.
Historically, zoom cameras have been utilized to perform manhole inspection and inspect a few ft down
the pipe utilizing a camera mounted on the end of a telescopic pole. This technology is commonly
referred to as a down look camera. Newer zoom cameras can pan 360 degrees and zoom up to 100-ft. in
6-in. diameter pipe and up to 700-ft. for larger pipe diameters.

This technology involves setting up the zoom camera at each manhole and inspecting the manhole and
pipes.  Potentially, the technology could allow for the inspection of an entire section of pipe from one
manhole to the next.  Zoom camera inspection has some of the same limitations as traditional CCTV pipe
inspection in that it cannot inspect what is beneath the fluid being conveyed through the pipe.  It is not
designed to replace conventional CCTV systems, but rather to screen and prioritize pipes for further
conventional CCTV work and/or cleaning pipelines.  The technology does not provide the detailed visual
evaluation of conventional CCTV. The primary advantage to the technology is improved production rate.
The set-up eliminates the need for cleaning prior to the inspection, as well as the inevitable down-time
associated with an obstruction to a crawler mounted camera.  An inspection crew can move through a
service area in an expeditious manner and highlight segments requiring a more detailed inspection.
Zoom camera inspection is a very efficient, cost-effective method of performing manhole inspections,
which has been its primary use. It is, however, limited in its ability to inspect pipe segments.  Image
resolution, lighting, and limitation in optical zoom are the primary disadvantages of this technology. The
technologies described below attempt to overcome these limitations with improvements to lighting and
zoom ability. This technology also increases the production rate of sewer inspections, as it collects data
at a speed several times faster than traditional CCTV inspection.  This is in part because pipes generally
do not have to be flushed and cleaned prior to inspection.
Zoom camera inspection is only useful for inspecting gravity sewers because its access to the sewer is via
a manhole.  Force mains and/or service laterals do not have the required access points to deploy this
technology.  As with all camera inspection technologies, zoom camera inspection can be used with any
pipe material.
Zoom camera inspection services are available from a variety of service providers.  Both regional and
national service providers have the ability to provide this service. It is not known if the use of the longer
range cameras with increased zoom capabilities is a commonly used inspection tool in the industry.
Provided below is a description of four manufacturers of zoom cameras used for the inspection of gravity
sewers.
No new zoom camera technologies under development have been specifically identified as emerging
technologies. Likely, the identified manufacturers will continue product development and increase
optical and digital zooming capabilities.  It is also likely that the technology will be equipped with a
digital  inspection system as described in Section 4.1.2. Table 4-2 provides  a summary description of the
zoom camera technology.
                                           Page 4-23

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Table 4-2: Zoom Camera Inspection Summary
SUMMARY
Sewer type
Material
Pipe size
Defects detected
Original application
Status
Advantages
Disadvantages
Gravity sewers only
Any
> 6-in.
Cracks, leaks, root intrusion, overall surface condition of pipe/manholes
Manhole inspection
Commercially available
High production rate, effective/efficient at prioritizing segments requiring
more detailed inspection/maintenance
Inability to inspect manhole to manhole for average diameter lines, potential
to miss significant defects
CUESIMX- Truck Mounted Zoom Camera
The CUES-IMX truck-mounted zoom camera provides video inspection for manholes and pipelines. The
CUES-IMX camera offers imaging technology with a 25:1 optical zoom that is stabilized and remotely
controlled by a telescopic boom.  The camera can record images from up to 300' into the pipeline. The
camera mounting fork is designed to pan the camera head 360° continuously, tilt mechanically 45° up or
90° down, and tilt optically 166°. The camera imager, optics, mechanics and electronics are housed in a
damage resistant, waterproof, rugged enclosure that is 7-in. in diameter and 16-in. in length.  The CUES-
IMX system includes the camera, high intensity discharge lighting heads, mast system and controller.
The manufacturer indicates that the system can be mounted within an inspection van, all-terrain vehicle,
or a trailer.

The system is equipped with data collection, GIS software and global positioning system (GPS)
equipment.  The GIS software and GPS equipment are used to create sewer maps in the field and create
an asset management database for the system. Defects detected during the inspection can be stored in a
database along with photos and video clips. All data is geo-referenced to the field collected GPS
coordinates. This is common to the industry and the subject of further discussion in a later section.

The objective of the CUES-IMX camera system is to increase the production rate of the inspection
process, as compared to traditional CCTV. The manufacturer indicates that an inspection process using
zoom technology has a production rate of five to eight times higher than traditional CCTV and is a useful
tool to efficiently characterize a collection system and prioritize segments for further inspection and/or
cleaning.  Inspections using the CUES-IMX camera provides mapping, inventory and condition
information that can be used immediately to reduce system operation and maintenance issues by quickly
identifying areas of high-risk due to blockage or structural defects. The risk of backups or overflows can
be assessed and addressed rapidly.

GE Technologies - Ca-Zoom PTZ and Quick View
GE Technologies offers three truck-mounted Everest Ca-Zoom Pan-Tilt Zoom (PTZ) cameras for sewer
inspection.  Each camera has a different PTZ camera head. The PTZ 140 has a 300:1 zoom capability
(optical 25:1, digital 12:1) and is equipped with two high-power 35-watt lights. The camera has  the
ability to record imagery up to 250 ft down a pipe segment with diameters between  15 in. and 60 in. The
PTZ100 has 40:1 zoom capability (10:1 optical, 4:1 digital), and four 5-watt light-emitting diode (LED)
lights.  The PTZ270 also has a 40:1 zoom capacity, but has eight 5-watt LED lights.
The smaller hand-held Quick View unit is a pole mounted camera with a total zoom  capability of 216:1
(18:1 optical, 12:1 digital). It has the ability to zoom to between 75 and 250 ft within pipe diameters of 6
in. to 60 in. The unit is mounted on an 18 foot telescoping pole.
                                          Page 4-24

 image: 






The benefits and limitations of these cameras are similar to those of the CUES-IMX camera system as
described above.

CTZoom Technologies - PortaZoom
Innovative Technology Products, Inc. offers sewer inspection with the PortaZoom camera, manufactured
by CTZoom Technologies.  The PortaZoom is housed in a compact enclosure, just 6 in. in diameter. The
camera pans more than 350° and has a 312:1 zoom capability (26:1 optical, 12:1 digital). The camera has
full-circumference integrated lighting, including peripheral lighting to reduce shadows. The PortaZoom
is operated by a computer, joystick and keyboard.  The PortaZoom can be mounted to any vehicle or
hand-held pole, and can zoom approximately 100 ft to 200 ft into pipes.

AquaData, Inc. -AquaZoom
AquaData Inc. also manufacturers zoom camera inspection equipment. They manufacture the AquaZoom
system though it is not commercially available.  The AquaZoom can be used on pipes with diameters of 6
in. or larger and can inspect pipelines for approximately 100 ft. It is normally mounted on either a truck
or tripod, which is claimed to provide better stability compared to pole mounted devices. It also utilizes a
built-in control center and video recording equipment to perform pipe inspections.

Aries Industries - HC3000 Zoom Pole Camera
The Aries HC3000 Zoom camera has a 432:1 zoom ratio (36:1 optical, 12:1 digital). The camera has two
LED lights, and is mounted on a 6-foot to 18-foot telescoping pole. The camera can view up to 100 ft
into the pipeline being inspected. The image is transmitted via radio frequency technology to a media
case, which houses a  radio frequency receiver and monitor. A small portable monitor is also available for
viewing the images as the camera zooms down the pipe. The pole mounted device provides easy
portability and rapid setup.

4.1.2   Digital Scanning

Digital scanning is a state-of-the-art technology within the camera inspection industry.  Like conventional
CCTV, digital cameras are transported through sewer lines using self-propelled crawlers.  Unlike
conventional CCTV systems, digital scanning uses one or two high-resolution digital cameras with wide-
angle lenses in the front, or front and rear, section of the housing. During pipe inspections, parallel
mounted lights are triggered at the same position in the pipe. The hemispherical pictures scanned are put
together to form 360° spherical images. There is one specific manufacturer that utilizes a single camera
with a wide angle lens to accomplish the same result.
During the scanning process, data are transmitted to a surface viewing station where it can be viewed in
real-time and recorded for later evaluation. The major  advantage to digital scanning technology is that it
is possible for the data to be assessed independently of the real-time sewer inspection.  By comparison,
conventional CCTV relies on a camera operator to pan, tilt, and zoom into critical areas for further
review. The image, as controlled by the operator, is stored. Therefore, if the  operator does not  see a
defect, the camera is not stopped for further investigation.
Digital scanning develops a full digital image of the pipe segment.  This allows the individual reviewing
the images to control  the direction of the PTZ features and to stop the image at any point to capture video
clips and images. The inner pipe surface can be "unfolded" providing a view of pipe conditions, which
permits computer-aided measurement of defects and objects. Digital scanning provides a more  consistent
and complete assessment of pipe condition. It provides a second level of quality control in the review
                                           Page 4-25

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process and allows other individual(s) involved in the process to gain insight into the pipe condition (e.g.,
designers, rehabilitation contractors, and utility owners).
Digital scanning technology is primarily used for gravity lines in the 6-in. to 60-in. diameter range.  Its
applicability for use in inspecting sewer laterals is limited since laterals are typically less than 6 in. in
diameter and access is generally through a small diameter clean-out. It is also limited in its ability to
inspect force mains. Like conventional CCTV technology, digital scanning is only able to provide useful
images above the waterline; force mains would have to be taken out of service and drained before digital
recording.  Access to force mains also typically restricts the use of digital and CCTV technology. Force
mains are pressurized and do not have access manholes to insert CCTV equipment.  Digital scanning can
be used with any pipe material. Table 4-3 provides a summary description of the digital camera scanning
technology.

 Table 4-3: Digital  Camera Scanning Inspection Summary
SUMMARY
Sewer type
Material
Pipe size
Defects detected
Original application
Status
Advantages
Disadvantages
Gravity sewers, limited applicability for force mains and service laterals
Any
6-in. to 60-in.
Cracks, leaks, root intrusion, overall condition of pipe
Inspection of piping
Commercially available, new applications under development
Increased QA/QC control, additional project personnel able to review/control
data imagery, able to make digital measurements of defects, can compare
data directly from one inspection to the next
More costly then CCTV, lower production rate compared to traditional
CCTV, only works above waterline.
Digital scanning camera systems are available from a variety of vendors. Several commercial
applications are specifically designed for the investigation of water, storm drain, and sewer pipelines.
The following are descriptions of some of the products available from several vendors.

Blackhawk-PAS - Sewer Scanning Evaluation Technology (SSET)
SSET was developed in Japan in 1994, and introduced through field trials in the United States in 1997.
The third-generation SSET was refined by Blackhawk-PAS for commercial marketing.  SSET uses two
digital image capture devices mounted on a remotely controlled tractor. One of the cameras records a
forward view of the pipeline while the other camera scans the side of the pipe to create a spiral,
perpendicular view. SSET can be used in pipes ranging from  8-in. to 36-in. diameter, operating at a rate
of approximately  13 ft per minute.

RapidView - IBAK, USA - Panorama
The RapidView-IBAK, USA Panoramo system was developed by IBAK Helmut Hunger GmbH & Co.
KG of Kiel Germany in partnership with RapidView, LLC. The application was first developed and used
in 2002.  The first application in the United States was in 2007.

The Panoramo system uses two high-resolution digital photo cameras with 186° wide-angle lenses fit into
the front and rear  section of the housing. During pipe inspections, parallel mounted xenon flashlights are
triggered at the same position in the pipe. The hemispherical pictures scanned are put together to form
360° spherical images.  The Panoramo can scan 8-in. to 48-in. diameter pipes at a speed of up to 70 ft per
minute in forward or reverse motion.
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During the Panoramo scanning process, the data are transmitted digitally to the inspection vehicle and are
at the operator's disposal. The scans can be viewed as live pictures for orientation purposes and for
locating any obstructions. In addition, the data are stored in the form of "PANORAMO films", on
removable hard disks or digital video discs (DVDs).
This image scanning method makes it possible for the pipe inspection to be assessed by personnel away
from the field. The reviewer has the ability to pan, tilt, or zoom in on potential defects as if in the truck
with the field crew.  The reviewer can stop at any position, turn a full circle, zoom, and complete the data
analysis. An unfolded view of the inner pipe surface which is available simultaneously gives the reviewer
a rapid view of the state of the pipe and permits computer-aided measurement of the position and size of
objects. The Panoramo system works in conjunction with WinCan Scan Explorer Software Version 8.

Envirosight - DigiSewer

The Envirosight DigiSewer system was originally developed by DigiSewer and manufactured by IPEK
(provider of crawlers and cameras to Envirosight). The DigiSewer was originally designed to be used for
borehole inspection and was first used in Europe in 2003. It was officially released to the North
American market in April 2007.

The DigiSewer uses one high-resolution photo cameras with 180° wide-angle fisheye lens, integrated into
the front of the rover crawler. The DigiSewer can scan pipes  from 6-in. to 60-in. diameter at a scan speed
of 70 ft per minute.  The DigiSewer can scan pipes over a length of approximately 650 ft.

Emerging Technologies
No digital scanning applications have  been specifically identified as emerging technologies.  Likely, the
identified  manufacturers will continue product development and increase optical and digital zoom
capabilities. The technology is four to five years old in Europe and Asia; however it has a limited history
in North America. The manufacturers and users listed above  are constantly developing new  ways to use
these products.  Our research indicates that future research will focus on enhancements to the software
used for defect recognition and digital defect measurements.  RapidView and Envirosight are developing
manhole inspection capabilities with the use of the digital scan cameras. Envirosight is also  planning to
increase the scan distance to approximately 1,650 ft by fall 2008 and provide improved scanning rates.

4.1.3   Camera Deployment

In a CCTV inspection, cameras are deployed into pipelines in a variety of ways. Mobile robots called
crawlers or tractors are available in a variety of sizes and configurations, thus enabling their use in a host
of pipes sizes. These are typically introduced into the sewer via a manhole. Cameras can also be
mounted to float rigs for inspecting large diameter pipes partially filled with water.  Pushrod cameras  are
typically used in smaller diameter pipes (6 in. and less) such as service laterals and are typically
introduced into the sewer through a cleanout.
This section describes innovations to vehicles used to carry CCTV cameras as well as technologies that
can be added to the conventional camera vehicles to further assist in CCTV inspection.
A variety of innovations have been applied to the tractors or crawlers which carry CCTV cameras. These
innovations include extra long range tractors/floats compared to the typical applications in use, smaller
than typical tractors that can be used for some laterals, tractors that are able to dispatch smaller lateral
cameras from the main line, and segmented robots that can bend around odd angles in small  diameter
pipes.
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Different camera tractor innovations are available from a variety of vendors. Several commercial
applications are specifically designed for the investigation of water, storm drain, and sewer pipelines.
Pushcams are used almost exclusively in smaller diameter sewers such as service laterals. Tractor
innovations have been broken down into four groups: small diameter tractors, long range tractors,
segmented tractors, and lateral launchers - tractors that can launch lateral cameras off of the main
inspection vehicle.

Pushcams
Pushrod camera, or pushcam, technology involves the inspection of pipeline via a small diameter camera
mounted to a pushrod and reel setup which produces video of the pipeline.  This technology is primarily
designed for laterals and small diameter force main applications.  Conventional pushcams use straight
view cameras capable of inspecting pipes of 2-in. or greater. Advancements include pushcams capable of
inspecting pipes smaller than 2-in. as well as steerable and pan/tilt pushcams.
Pushcams are typically used in an environment where it is otherwise impossible to get photographs or
video footage such as a small diameter water, sewer, or drain pipes. Typically, they are used in
applications where crawlers/robotic camera vehicles are unable to function due to their larger size.
Conventional pushcams systems are comprised of a camera/probe, cable/reel, and
computer/recorder/controller. The probe used to advance the camera is usually a semi-rigid rod,
constructed of fiberglass.  The primary limitations are image quality, lighting, and ability to move past
obstructions. Table 4-4 summarizes a variety of commercially available pushcams.
Table 4-4: Pushcam Product Comparison
PRODUCT
(VENDOR)
CrystalCam Push Camera
(Inuktun)
Flexiprobe
(Pearpoint)
Hydras
(Rapidview-IBAK, USA)
Orion
(Rapidview-IBAK, USA)
Orion L
(Rapidview-IBAK, USA)
Push Camera
(Insight Vision)
PIPE
DIAMETER
>2-in.
1-in. to 8 -in.
>2-in.
>4-in.
>4-in.
1-in. to 12-in.
INSPECTION
LENGTH

500-ft



300-ft
NOTES
High resolution low lux camera - highly
effective in low light environments. Can be
tractor mounted, can be used as a reverse
camera

Straight view camera only
Pan and tilt functions
Pan and tilt, includes "steer stick" allowing
device to be steered around bends or turns
Uses Clearview line of camera heads, large
10. 4 in. LCD monitor
Tractors/Crawlers

Tractors and crawlers are mobile robots used to deploy CCTV through a pipeline. Most are wheeled or
tracked, and are tethered via a cable to a controller unit located near the point of entry to the sewer
system. Conventional CCTV inspection tractors are larger vehicles that are not able to get into smaller
pipes or laterals. Many of the tractors are not steerable and can only inspect pipe runs of 300 to 500 ft.
Advancements in technologies now include lateral launchers that are able to deploy smaller diameter
pushcams into laterals; small diameter tractors that can be deployed in pipes as small as 4 in. in diameter;
long range tractors that can inspect pipes at great distances from the point of entry; and segmented robots
that can bend around odd bends or angles in small diameter pipes.  Tables 4-5, 4-6, and 4-7 summarize a
selection of commercially available innovative tractor and crawler technologies.
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Table 4-5: Lateral Launcher Product Comparison
PRODUCT
(VENDOR)
IBAKLISY150-M
(RapidView-IBAK, USA)
LAMP
(CUES)
Lateral Evaluation Television
System
(Aries Industries)
Lateral Inspection System (RS
Technical Services)
MAINLINE
Pipe
diameter
>6-in.
6-in. to 24-
in.
>8-in.
8-in. to 24-
in.
Inspection
length


800-ft
1,000-ft
LATERAL
Pipe
diameter

2-in. to 6-
in.
3 -in. to 6-
in.
4-in. to 8-
in.
Inspection
length

>80-ft
80-ft
100-ft
NOTES
Tungsten carbide
wheel for grip

Can ID pipe locations
with locator beacon

Table 4-6: Small Diameter Tractor Product Comparison
PRODUCT
(VENDOR)
ELK T100 Mini
(Pearpoint)
KRA65
(RapidView - IBAK, USA)
Mighty Mini Transporter
(RS Technical Services)
Rower 100
(Environsight-IPEK)
Versatrax 100
(Inuktun)
Xpress Silver-Bullet Crawler
(Insight Vision)
PIPE
DIAMETER
4-in. to 10 -in.
>4-in.
4-in. to 12-in.
4-in. to 12-in.
>4-in.
4-in. to 15 -in.
INSPECTION
LENGTH
500-ft

500-ft
660-ft
600-ft
600-ft
NOTES

Steerable, electric stabilizing function

Steerable, PVC wheel with titanium spikes for
traction
Tracked crawler
4-wheel drive crawler
Table 4-7: Long Range Tractor Product Comparison
PRODUCT
(VENDOR)
Versatrax 300 VLR
(Inuktun)
Responder
(RedZone)
PIPE
DIAMETER
>12-in.
>36-in.
INSPECTION
LENGTH
6,000-ft
5,280-ft
NOTES
Modular construction for onsite customization,
optional reverse camera can be mounted on
crawler
Skid steer enabled tractor, Kevlar reinforced
buoyant cable, submersible to 500-ft
Segmented Robots

Electromechanica, Inc. designs custom inspection robotics and other applications on an as needed basis.
For example, the client may have a specific type of small diameter pipe system containing tees or wyes,
or other angles that a typical tractor or crawler would not be able to navigate. One such development is
the Internal Pipe Inspection Robot. This design uses a unique "inchworm" movement which optimizes
movement within the pipe. The robot itself consists of three arm linkages that expand radially to force the
different segments to grip the inside of the pipe and move it along. The multiple segments also can be
useful in overcoming obstacles or looking down laterals. The robot uses pneumatic cylinders to provide
force to move the robot through the pipe. The robot can be outfitted with cameras, sensors or tools to
achieve many different types of jobs in pipes including pipe inspection. As stated above, this is not a
commercial product, but one that must be custom ordered for the client's specialized needs.
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Emerging Technologies
       •   Pushcams - The IPEK Agilios pushcam system was developed for small diameter pipes and
           has pan/tilt capability. It works in conjunction with the vision control unit and is battery
           powered.
       •   Autonomous Crawlers - An autonomous crawler does not require a real-time remote
           operator. The crawler's behavior is programmed in advance of deployment. The vehicle is
           programmed to cue off of particular environmental landmarks. For instance, RedZone
           Robotics, a Pittsburgh, Pennsylvania based company, has designed a robot that constantly
           monitors the diameter of the pipe as the robot progresses through the pipe. Infrared sensors
           atop the vehicle sense when the distance to the roof of the pipe alters radically, which the
           robot then interprets as a manhole. The vehicle may be programmed to stop at the first
           manhole it encounters, or  stop after encountering some specified number of manholes.
           Autonomous crawlers are  beginning to enter the marketplace.
       •   Autonomous Floaters - Automatika, Inc. based in Pittsburgh, Pennsylvania, is developing
           the prototype of a neutrally buoyant, untethered pipe inspection robot called PipeEye. The
           robot is a 12-in. sphere designed to float in pipes greater than 24 in. in diameter. Cameras
           and lights will operate above the waterline, and ultrasonic transducers will operate below the
           waterline.  The PipeEye system is derived from an oil/gas pipeline inspection module co-
           developed by Automatika and Shell Oil.  Currently, the system does not yet have a product
           status.


4.2    Acoustic Technologies

Acoustic technology in general terms uses measuring devices to detect vibrations and/or sound waves. In
pipeline assessment, acoustic sensors are used to detect signals emitted by defects and are utilized by a
variety of commercially available products. Acoustic technologies are used extensively for inspection of
water mains; therefore,  this category of inspection technology can also be used for force main inspection.
There are three distinct classifications  of acoustic technologies:
       •   Leak detectors, which are used to detect the acoustic signals emitted by pipeline leaks.
       •   Acoustic monitoring systems,  which are used to evaluate the condition of PCCP.
       •   Sonar,  or ultrasonic, systems, which emit high frequency sound waves and measure their
           reflection off the pipe wall in order to detect a variety of pipe defects.
Table 4-8 summarizes these classifications of acoustic technologies.
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Table 4-8: Acoustic Technology Summary
SUMMARY
Sewer type
Material
Pipe size
Defects detected
Original application
Status
Advantages
Disadvantages
IN-LINE LEAK
DETECTORS
Force mains, gravity
sewers
Any
>4-in.
Leaks
Leak detection in
pressurized water lines
Commercially available
for sewer inspection
Can detect very small
leaks.
Requires minimum flow to
be carried through pipe
ACOUSTIC MONITORING
SYSTEMS
Force mains
PCCP
>18-in.
Broken pre-stressed wires
Monitoring PCCP water lines
Commercially available for
sewer inspection
Useful as a screening
technique prior to more
detailed inspection
Only detects general distress
SONAR/ ULTRASONIC
Force mains, gravity sewers
Any
>4-in.
Pipe wall deflections,
corrosion, pits, voids, and
cracks, debris
Maritime use
Commercially available for
sewer inspection
Suitable for pipes of any
material and a wide range of
diameters
Only inspects pipe below
the waterline
4.2.1   Leak Detectors

Leak detectors are devices used to detect the sound or vibration produced by leaks in pressurized
waterlines or in sewers. These include hand-held listening devices such as listening rods, underwater
microphones (also known as aqua phones, sonoscopes, water phones or hydrophones), and geophones
(ground microphones); leak noise correlators; and in-line devices which collect information on leaks
remotely.  Listening devices and leak noise correlators are widely available, and have been used for leak
detection for decades. In-line leak detectors are a more recent advancement in the use of acoustic
technology for condition assessment of pipes.
The simplest forms of leak detector are mechanical listening devices. These include listening rods and
aquaphones, which are both metallic rods fitted with an earpiece. These devices are operated by placing
the rod in direct contact with pipes, allowing the device operator to hear leaks through the  earpiece.
Geophones are another type of listening device; these are placed on soil or pavement above a pipe,
allowing the operator to hear the sound from leaks as it is transmitted through the soil. Listening rod and
aquaphones may also be electronic, these are similar to the mechanical devices described above but also
include special elements such as noise filters, adjustable amplifiers, and sensing elements such as
piezoelectric materials; leaks can be detected either by operators listening through headphones or in some
cases by soundmeters that can store the sound levels emitted by leaking pipes.
Leak-noise correlators are a more complex and accurate type of leak detector, which have  been used for
leak detection since the 1980s. These are computer-based devices which are used to measure sound or
vibration at two points on a pipe, on either side of a suspected  leak.  Depending on the device, the
measurements are made by a vibration sensor such as an accelerometer attached to pipe contact points or
an underwater microphone which is inserted into the pipe itself.  Signals detected by the sensor are
wirelessly transmitted to the correlator, which pinpoints the location of leaks based on the  time lag
between the leak signals measured from the two points.
The most complex forms of leak detectors are in-line systems, which are deployed in a pipeline and
continuously monitor leakage. The rest of this section focuses on these systems.  There are several
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commercially available in-line leak detectors which utilize acoustic technologies for pipe condition
assessment. Both regional and national service providers have the ability to evaluate wastewater systems,
although the technology is far more prevalent in its use for condition assessment of water distribution
systems. Provided below is a description of several of these products.


Sahara®-Pressure Pipe Inspection Company
The Sahara system was originally developed by WRc for detecting leaks in pressurized water lines, and is
a proven technology for that application.  In the United States, the Sahara system has begun to be used for
wastewater collection systems. A series of pilot studies using the Sahara for wastewater pipeline leak
detection were conducted in the United Kingdom in 2005 and North America in 2006.  The system is now
available in the United States from the Pressure Pipe Inspection Company.
The Sahara system consists of a sensor head and a hydrophone, which is an electrical instrument used to
detect or monitor sound under water.  The sensor head is inserted into a pipe through any access point
greater than three inches in diameter.  As the sensor head is transported through the pipe line by product
flow, acoustic signals are picked up at the surface by the hydrophone. The signal is then fed through a
cable, and from there to processing equipment. The system operator is able to hear signals from the
system directly as well as view the signal on a computer with spectrogram software.  The system locates
leaks by identifying acoustic signals; the size of leaks can be estimated based on the  acoustic signal
recorded by the device.
The Sahara system can be used in pipelines of any material to detect leaks as slow as approximately 0.25
gallons/hour. It can be used to inspect force mains 4-in. in diameter and larger.  The system requires a
minimum flow velocity of approximately 3 ft/s to ensure the device can move though the pipe.
Additionally, pressure within the pipe must be between 10  and 150 psi in order for the  system to
recognize leaks.


Smartball®"- Pure Technologies

The Smartball® leak detector was made commercially available by Pure Technologies in 2005. It is a
proprietary system maintained by Pure Technologies.  The technology is only used for inspections of
pressure pipelines. It can be used for any pipeline material.

The Smartball® consists of a neutrally buoyant, foam ball equipped with an instrumented aluminum inner
core. The aluminum inner core contains several sensors including an acoustic sensor, accelerometer,
magnetometer, temperature gauge, and pressure gauge. The inner core also contains a microprocessor
with an ultrasonic transmitter. The system is powered by a DC battery and contains  a data logger. The
Smartball® can be inserted into a pipeline and travel with the water flow for more than twelve hours,
collecting data on the collection system with a single deployment. The Smartball® has a diameter of 2.6-
in. and can be used on a pipe with 10-in. or greater in diameter. A minimum flow velocity of 1.64 ft/sec
is required to convey the sensor.
The system can be inserted into a full or partially full pipe, and is carried along by the flow of water or
wastewater. The Smartball®  is silent; therefore its acoustic sensor can detect the  sound of very small
leaks in the pipeline. As the Smartball®  passes through the pipe its progress can be tracked by a variety
of methods, allowing for leak  location to be determined within one meter of accuracy.  The system can
operate for up to twelve hours before it is retrieved and data downloaded.

LxSentry - LxSix Photonics,  Inc.

The LxSentry pipeline monitoring system was recently introduced by LxSix, Photonics Inc.  LxSentry is a
highly sensitive fiber optic system designed to detect leaks in gas pipelines. Acoustical sounds are
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classified by the proprietary Red Alert software, which is capable of distinguishing between pipeline
leaks, tampering, intrusions, and machinery and vehicles operating in the pipeline vicinity.  Minimal
information on the details of the operation and use of this product is currently available. No information
was available on the use of the technology for water and/or waste water systems.

4.2.2   Acoustic Monitoring Systems

Acoustic monitoring systems are installed along PCCP to provide continuous monitoring of the general
condition of the pipe.  PCCP has been used historically for large diameter force mains, and has been
subject to failure due to internal or external corrosion.  The systems work by detecting the acoustic signal
produced by breaking  or broken prestressed wire within pipes. While the systems do not identify
individual defects, they are useful as screening techniques to determine if further condition assessment
should be performed.  There are currently two technologies available that provide continuous acoustic
monitoring of PCCP.  These products are described below.

Acoustic Emission Testing (AET) - Pressure Pipe Inspection Company
Acoustic Emission Testing (AET) is as an acoustic monitoring system used primarily to monitor the
deterioration of PCCP water mains. It has also been used to evaluate sewage force mains. AET is based
on the detection of the acoustic energy released when prestressed wire breaks or deflects. The system
detects general distress in the pipeline by determining the frequency and number of wire breaks, or wire
related events, over a period of time.  The AET system determines the location of the wire related events
based on the arrival time of the acoustic signals at a series of sensors within the pipe. Since the technique
does not detect the number of broken  wires, but rather general distress in a given section of pipeline, it is
best used as a screening technique prior to utilizing other methods to pinpoint defects.
The AET system is made up of a series of units located along the pipeline.  Each unit contains a sensor
(either a hydrophone or an accelerometer) and a signal processor, a base station, and a precision timing
device. The hydrophones are inserted into the pipeline through taps at a spacing of approximately 500 to
3,000 ft; spacing is largely dependent on pipeline diameter (smaller pipes require closer spacing than
larger ones). The accelerometers are surface mounted; spacing is more flexible when this type of sensor
is employed.  The signal processor is a small mobile computer that is located close to the hydrophone. It
monitors the signals detected by the hydrophone and transmits signals that indicate wire related events to
the base station. The base station consists of a personal computer, a wireless communication module, and
an internet communication module. The precision timing device, a GPS antenna and processor, provides
location information on each sensor and determines the timing of acoustic events.
AET can be used to monitor active distress in PCCP 18-in. or greater in diameter.  The system works
while pipelines are fully operational.  The technique is valuable for providing advanced warning  of pipe
failure, and for screening pipe networks to determine which pipes are deteriorating.  However, the
technique cannot detect individual  defects within a pipe.


SoundPrint®- Pure Technologies

SoundPrint® is a patented acoustic monitoring technology used to provide continuous, non-destructive
remote monitoring of water and wastewater pipelines,  storage tanks and other structures. Introduced in
1993, the original version of SoundPrint® used hydrophones to detect breaks in prestressed wire in
PCCP. The newer SoundPrint® AFO system, introduced in 2005, uses acoustic fiber-optic cable for
detecting acoustic signals.

Soundprint® AFO monitoring of PCCP involves the deployment of fiber-optic cable into the pipeline.
The cable is inserted into pipelines through new valves installed  in manholes. Because the entire fiber-
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optic cable acts as a sensor, up to 12,000 ft of pipeline can be monitored from a single access point. The
sensor does not contain any electronics, therefore there is little to no background noise created by the
device.

4.2.3   Sonar and Ultrasonic Testing

Sonar, an acronym for Sound Navigation and Ranging, was developed in 1906, and is widely used for
maritime use.  The first use of sonar for inspection of pipelines was carried out by WRc in 1987.  Sonar
testing involves very high frequency ultrasonic sound waves that reflect off the material being inspected,
allowing for the detection of defects.

Sonar/ultrasonic inspections of pipelines are accomplished by passing a sonar head through the pipe being
inspected.  Depending on the size and flow conditions of a pipe, the sonar head is deployed into the
pipeline on a raft, skid, or robotic tractor.  As the sonar head moves through the pipeline, it sends out very
high frequency ultrasonic signals, which are reflected by the pipe walls and then received by the sonar
head.  The reflection of the signals changes when there is a change in the material it is being reflected by,
allowing for the detection of defects. The time between when the signal is  sent and received can be used
to determine the distance between the sonar head and the pipe wall, as well as to determine the internal
profile of the pipe.
Sonar inspection results  in a detailed profile of the pipe wall below the water surface, which can be
analyzed by a variety of methods.  Sonar can detect pipe wall deflections, corrosion, pits, voids, and
cracks.  Sonar inspection can also detect and quantify debris, grease, and silt, and can distinguish between
hard and soft debris; however, defects in the pipe wall can sometimes be obscured by grease and debris.
According to Thomson et al. (2004), defects greater than 1/8 inch (3 mm) can be detected. This applies to
pipe wall pitting and cracks as well as debris accumulation. Sonar does not require bypass pumping or
pipe cleaning.  Sonar inspection can be used in areas  of poor visibility where it is difficult to use CCTV
inspection. It is a versatile inspection method and can be used for inspecting gravity sewers and force
mains.
One drawback to sonar is that it can only be  operated in air or in water, not in both simultaneously. In
some cases, a sonar system is utilized with a CCTV system, so that inspection  of pipes both above and
below the waterline can be accomplished simultaneously. In order to overcome this limitation, research is
being done into development of systems with separate transducers, one for  use in air and one in water, so
that inspection of partially filled pipes can be accomplished. Additionally,  longitudinal cracks in pipes
can be difficult to detect.
Commercial sonar pipe inspection tools typically consist of an underwater scanning transducer, a sonar
processor, and a color monitor.  Table 4-9 highlights  a selection of sonar-based pipe inspection products.
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Table 4-9: Sonar Product Comparison
DEVICE:
VENDOR
Amtec Sonar:
Amtec Surveying, Ltd.
A-SIS
Aquacoustic
Envirosight
PipeEye:
PipeEye International
RVS2:
R&R Visual
Sonar Profiler System
(submerged): CUES
Sonar Profiler System
(semi-submerged): CUES
Sonar Sewer Profiling
Attachment: Redzone
Sonar Sweep Attachment
Redzone:
TISCIT:
Amtec Surveying, Ltd.
UltrascanCD:
GE Oil & Gas
UltrascanDUO:
GE Oil & Gas
Ultrascan WM:
GE Oil & Gas
Ultrasonic Inspection Robot
Inspector Systems
Wavemaker:
Guided Ultrasonics
SEWER TYPE/
PIPE SIZE
Force mains
>21 in.
>12 in.
Gravity
>4 in.
Force mains, gravity
>10 in.
>10 in.
Force mains
>12 in.
>12 in.
Force mains, gravity
>36 in.
Force mains, gravity
>36 in.
Gravity
>21 in.
Force mains, gravity
Force mains, gravity
>24 in.
Force mains, gravity
Force mains
12 -20 in.
Force mains, gravity
>2in.
DEFECTS
DETECTED
Deformations, holes, breaks,
and pipe wall loss.
Pipe size & distortion,
holes, debris, scour, erosion
Pipe diameter, shape
capacity, corrosion, cracks,
debris
Build-up, deformities, flow
restriction, water level
Open cracks, debris,
sediment
Defects, blockage, debris
Defects, blockage, debris
Blockages, deformations,
capacity, sediment
Blockages, deformations,
capacity, sediment
Deformations, holes, breaks,
and pipe wall loss
Axial cracks
Wall loss and cracks
Wall loss
Wall loss (measures wall
thickness)
Wall loss
NOTES

Combines sonar and
CCTV
Attachment for CCTV



Combines sonar and
CCTV
Attachment for the
Responder platform
Attachment for the
Responder platform
Combines sonar and
CCTV



Incorporates high-
resolution CCTV
Uses guided waves
(Lamb wave), mounted
to outer surface of pipe.
4.3    Electrical and Electromagnetic Methods

Several sewer evaluation techniques utilize electrical or electromagnetic currents. The electrical leak
location method is used to detect leaks in surcharged non-ferrous pipes.  Eddy current testing (ECT) and
remote field eddy current (RFEC) technology identify defects in ferrous pipes.  Magnetic flux leakage
(MFL) inspection is widely used in the oil and gas industry to measure metal loss and detect cracks in
ferrous pipelines. Table 4-10 summarizes these technologies.
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Table 4-10: Electrical and Electromagnetic Methods Summary
SUMMARY
Sewer type
Material
Pipe size
Defects detected
Original application
Status
Advantages
Disadvantages
ELECTRICAL LEAK
LOCATION
Force main, gravity
sewers, service laterals
Non-ferrous
>3-in.
Cracks, leaks
Leak potential in
geomembrane liners
Commercially available
for wastewater pipes
Available for service
laterals
Gravity pipes must be
filled prior to inspection
ECT/RFEC
Force main, gravity sewers,
service laterals
Ferrous
>2-in.
Metal loss, cracks, leaks,
broken wire, graphitization,
wall thickness
Inspection of piping and
tubing including boilers, heat
exchangers, cast iron pipes,
and gas pipelines.
Commercially available for
wastewater pipes
Can be used on pipes of most
diameters, can be used to
locate a variety of defects.
Limited to ferrous pipes,
typically requires post-
processing of data by vendor.
MFL
Force main, gravity sewers,
service laterals
Ferrous
2-in. to 56-in.
Metal loss, circumferential
and longitudinal cracks
Petrochemical industry
Commercially available,
limited use in wastewater
applications
Extensive experience with
method in the oil and gas
sector
Has not been extensively
used for assessment of
sewer pipes.
4.3.1   Electrical Leak Location Method

The Electrical Leak Location Method was first developed in 1981 for the inspection of geomembrane
liners.  The method became commercially available in 1985, and is one of the most widely used
techniques for detecting leaks in geomembrane liners. The technique involves placing an electrode on
either side of the material being tested, and connecting voltage to each electrode.  Because the material
being tested is an electrical insulator, voltage only flows through holes in the material. The area of
defects in the material has high current density, which can be detected by measuring electrical potential in
the survey area.  Although primarily used for geomembrane liner inspection, the technique is also
applicable to pipe inspection.
As this technology relies on the pipe material being an electrical insulator, it can only be used on non-
ferrous pipes. The technology is useful for inspecting force mains, service laterals, and smaller gravity
lines. While it is possible to inspect larger diameter gravity lines, since the technology requires gravity
lines to be surcharged, the time and effort required to fill larger pipes might make this inspection method
infeasible.
Although there are more than twenty commercial providers of electrical leak location services for
integrity monitoring of geomembrane liners, the Focused Electrode Leak Location (FELL) is the only
application developed specifically for detecting leaks in pipelines. FELL, also referred to as Electro-Scan
technology, and was developed in Germany by Seba Dynatronic in 1999.  GRW Engineers, Inc. has
introduced the FELL system in the US. The FELL system identifies leak potential in non-conductive (i.e.
non-ferrous) sanitary sewer mains, gravity lines, and service laterals using electrical continuity
technology. The original application, FELL-41, was designed for use in force mains. A technique has
been devised to allow for the inspection of gravity sewers by this method as  well.  The corporation later
developed FELL-21 for inspection of service laterals.  As of 2004, there were three electro-scan devices
located in the United States, two of which are owned by GRW Engineering in Louisville, KY.
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FELL 41- Seba Dynatronic/Metrotech

FELL, or Electro-Scan, inspection is accomplished by feeding a mobile electrode, called a sonde, through
the pipe of interest.  Simultaneously, a fixed surface electrode, usually a metal stake, is placed in the
ground. Electrical current is generated by the sonde and flows through the water within the pipe, through
the pipe wall and earth surrounding the pipe, and to the surface electrode. As water, earth, and the
connecting cables have a low electrical resistance and the pipe material has a high electrical resistance,
very little current flows between the two electrodes. However, if a leak exists in the pipe, the electrical
current passes through it easily; the larger the defect, the greater the current that flows through. The
electrical current flowing between the two electrodes is measured by the sonde; this data is then
transmitted to a laptop computer, which records data and displays graphically the current flowing through
the pipe.
The technique only detects defects in surcharged portions of a pipe; to inspect the entire circumference of
pipes that are typically not surcharged, such as gravity sewers, the pipe must first be prepared by
completely filling it with water. Two techniques are used to fill pipes in preparation for FELL-41
investigation. The first involves plugging the downstream manhole and then filling the pipe with enough
water that the pipe is covered at the upstream manhole; this  method can be quite time-consuming and may
result in back-up of service laterals.  The alternative method involves the use of a sliding pipe plug. The
sonde is attached to the upstream side of the plug, which is manually pulled a short distance down the
pipe.  The upstream portion of the pipe is filled so that the sonde is submerged, and then the plug and
attached sonde is pulled through the pipe,  so that the entire pipe wall can be assessed.
FELL-41 is suitable for inspecting force mains ranging from 6-in. to 60-in. in diameter. The system only
works on non-conductive pipes and lined metallic pipes, and can only detect defects below the water line.
Although gravity sewers can be manually  filled to allow for a complete inspection; the process of
surcharging large diameter pipes requires extensive time and preparation. The product can be used to
detect leaks caused by radial and longitudinal cracks, as well as faulty joints.

FELL 21 - Seba Dynatronic/Metrotech
The FELL-21works on the same principle as FELL-41, but is designed for use in 3-in. to 6-in. diameter
service laterals. Rather than being deployed through the pipeline via a haul line, this device is inserted via
a cleanout and moved through the pipe with a push rod.  Like FELL-41, the device can only be used for
the inspection of non-conductive pipes or non-ferrous pipes. FELL-21 detects leaks caused by radial and
longitudinal  cracks, as well as faulty joints.

4.3.2  Eddy Current Testing and Remote Field Eddy Current Technology

ECT and RFEC technology involve the generation  of electric currents and magnetic fields to investigate
the condition of ferrous material.  ECT pipe inspection involves the use of an alternating current magnetic
coil to induce an electric current in conductive pipes. In turn, the electric current generates small
magnetic fields or eddy currents in opposition to the coil's magnetic field, which results in a change in the
impedance of the coil. As the magnetic coil transverses the  pipeline, the change in impedance is
measured, allowing for the identification of defects. The effectiveness of ECT for pipeline inspection is
limited by an electromagnetic phenomenon termed "skin effect".  The density of eddy currents decreases
exponentially with depth. This limits the detection of defects to those located on the surface of the pipe
nearest the magnetic coil, because defects  located deeper within the pipeline cannot be measured.
The RFEC method was developed to surmount the  limitations of standard eddy current testing. This
method can detect both internal and external defects in pipelines. RFEC involves the deployment of a
probe consisting of multiple magnetic coils, an exciter coil and one or more detector coils, through the
pipeline. As in standard eddy current testing, eddy currents  are induced in the pipe wall.  These direct
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currents quickly attenuate as they flow along the pipe wall towards the detector coil that is typically
located approximately two pipe-diameters apart from the exciter. A second magnetic field passes from
the exciter to the outside of the pipe and flows along the outer pipe wall, then back into the interior of the
pipe to reach the detector.  This remote field attenuates very slowly along the outer pipe wall, and is
therefore much stronger then the direct field when it reaches the detector. Pipeline defects and pipe wall
thickness affect the propagation of the magnetic fields along the pipe walls, thereby altering the signal
received by the detector. This allows for the identification of pipeline defects.
ECT and RFEC testing are primarily used to detect defects in ferrous pipe walls, such as pitting,
corrosion, leaks and cracks. These testing methods can be used for the inspection of small-diameter
pipes, in some cases as small as two inches in diameter, as well as very large diameter pipelines.
ECT/RFEC can be used in empty, full, and partially full pipelines. Devices utilizing ECT and RFEC
technology can be used to inspect force mains  and gravity sewers. However, since most gravity sewers
are not constructed of ferrous materials, the technology has limited use for this application.
ECT and RFEC testing services for ferrous structures are available from a variety of vendors.  Several
commercial applications are specifically designed for the investigation of gas, water, and sewer pipelines.
The following are descriptions  of some of these applications; as these technologies use the same basic
principal, the summaries focus  primarily on the differences between the various applications.

Broadband Electromagnetic Methodology (BEM) - Rock Solid Proprietary Limited (Pty. Ltd),
Australia
BEM was originally developed by Rock Solid Pty. Ltd for use in the Australian mineral exploration
industry. The technology has since been modified for use in pipeline inspection, and has been used for
this purpose in both the United States and Europe. Unlike other RFEC applications, BEM is frequency
independent, allowing operation of the device to be modified based on the material being  investigated and
site conditions. This reduces the likelihood that the device will be affected by electromagnetic noise,
which can occur with the use of other ECT/RFEC applications.
BEM has primarily been used for condition assessment of water mains. The technology can only be used
on ferrous pipes, but does work through thick coatings and linings. This technology can be used to detect
a variety of pipe defects including cracks and anomalies in the pipe wall. Thomson et al. (2004)
conducted field demonstrations of this method, and they state it is able to detect metal loss to 0.04 inch
(1mm). BEM can also be used to measure wall thickness, quantify graphitization, and locate broken wires
in PCCP.
BEM pipeline inspection can either be accomplished internally or externally.  Internal pipeline inspection
generally requires the pipeline to be taken out of service and emptied prior to deployment of the BEM
device.  As an alternative, the BEM device can be waterproofed.  Internal inspection of pipelines can be
accomplished in large diameter pipes by either pulling or pushing the device through the pipeline. A
robotic version of the application is available for smaller pipelines (less than 36-in. in diameter). Results
of pipeline inspections using BEM cannot be analyzed on-site; rather, results must be post processed.
Special software is used to create a topographic map of the pipeline which can then be analyzed to detect
pipe defects.

Hydroscope - Hydroscope, Inc.
The Hydroscope was developed as a collaborative effort between Hydroscope, Canada and EPCOR Water
Services (Edmonton, Canada's privatized water utility). The application was first used in 1995 in Canada
and became commercially available in the United States in 1996. However, the U.S. licensee for
Hydroscope is currently in bankruptcy. Therefore, the technology may not be available in the U.S.
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Originally developed for inspection of waterlines, the technology has since been used for the inspection of
sewer mains.
The Hydroscope consists of a series of stainless steel modules embedded with circuitry, creating a flexible
probe which can travel through pipelines.  The probe is connected to a computer in a service vehicle by a
tether and data cable.  Data cannot be analyzed in the field; rather, data are analyzed at the Hydroscope
Analysis Center with a proprietary software package called HYDA or the more advanced HYREL.
Like all ECT/RFEC-based pipeline inspection applications, the Hydroscope can only be used in pipes
composed of ferrous material. One advantage of the Hydroscope system is that it functions  in both dry
and submerged conditions. Probes are available for pipe diameters in the range of 6-in. to 15-in.  The
technology can detect pitting, corrosion, graphitization and wall thinning in pipes.

See Snake Tool - Russell NDE Systems, Inc.

Russell NDE System's, Inc.'s See Snake is a small, flexible device which uses RFEC technology to detect
corrosion and pitting in pipelines and to measure wall thickness and surface area. The tool can also detect
areas of pipe under external stress such as movement of soil, poor support, rippling, bridging and denting.
This technology is primarily intended for inspection of pipes before purchase or after construction to
ensure pipeline integrity, and after a pipeline failure to determine if there are additional defects in the
vicinity of the break.
Unlike most RFEC devices, which pass  signals through a data cable, signals from the See Snake are
detected from above ground. This allows  for tracking the tool as it passes  through the pipeline. Another
distinguishing feature  of the See Snake is that data analysis can be performed on site during  the
inspection, unlike other technologies which require off-site analysis.
The See Snake is primarily used in the oil and gas industry.  Currently, the tool is only available  for small
pipes, ranging in size from 2-in. to 8-in. in diameter. Given the small size  of the device, and its ability to
be pushed through pipelines by liquid, the See Snake is potentially viable for inspection offeree  mains.


P- Wave ® - Pure Techn ologies
Pure Technologies'  P-Wave3 system generates an electromagnetic field and detects changes induced in
the field by broken wires in PCCP.  Results of P-Wave inspection include  an estimate of the number of
broken wires, as well as their location. The technology allows for the evaluation of a pipe's current
condition and the identification of distressed areas. The system is available for use in sewer pipes;
however, the pipe must be  empty to use the product. P-Wave inspection is often followed up with the use
of an acoustic monitoring technology, such as Soundprint®, also available from Pure Technologies.

Remote Field Eddy Current/Transformer Coupling (RFEC/TC) - Pressure Pipe Inspection Company

Pressure Pipe Inspection Company's patented RFEC/TC is specifically designed for use in pre-stressed
concrete pipe, including embedded Concrete Pipe, lined cylinder pipe, and bar-wrapped pipe. Rather than
detecting defects such as corrosion, pitting, and leaks, this technology is primarily used to detect and
quantify broken wires within the concrete pipe to determine whether pipe segments need further
monitoring, repair, or replacement.  In this application, the electromagnetic field generated by the exciter
is amplified by the pre-stressed wires within the pipe.  Signals generated by broken wires can be
differentiated from those generated by intact wires.
RFEC/TC is effective  for inspecting pipes 25-in. in diameter and larger. The largest pipe inspected to
date is 252-in. In addition to broken wires, RFEC/TC can detect manholes, blow-offs, short pipe lengths,
 ! P-Wave stands for Polar Wave
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cylinder thickness, cylinder composition, wire pitch, diameter and wraps (Pressure Pipe Inspection
Company, n.d.).  RFEC/TC can be used for the investigation of both force mains and gravity sewers.

Emerging Technology
Due to the versatility of RFEC testing for the inspection of pipelines, several institutions are working on
the development of new applications.  The Gas Technology Institute is currently developing a tool for the
inspection of gas pipelines of a variety of diameters, including ones with valve and bore restrictions and
tight bends.  The Southwest Research  Institute has recently developed an inspection technology for 6-in.
to 8-in. diameter gas pipelines that couples an RFEC system to a robotic transport tool, the Explorer II,
developed by Carnegie Mellon University's Robotics Engineering Consortium. Monash University in
Australia has developed a RFEC tool called TESTAU. This instrument provides an improvement to the
quality of visual data over other RFEC tools.

4.3.3   Magnetic Flux Leakage  Detection

MFL is a widely used inspection technique for oil and gas pipelines.  The MFL technique was first
developed in the 1920s and 30s for materials testing.  The Tuboscope, which became commercially
available in  1965, was the first tool specifically developed for pipeline inspection.
MFL detection involves the placement of one or more magnets near a pipe wall, leading to the
inducement of a direct current magnetic field in the pipe wall. The strength and direction of magnetic
fields are represented by flux lines. When a magnet is near a  conductive pipe wall, the majority of flux
lines pass through the pipe wall.  However, in areas of metal loss, less flux can be carried than the intact,
full wall sections of pipe. This leads to leakage of flux from pipe areas which have undergone metal loss,
as well as a change in the shape of the induced magnetic field. Flux leakage is detected by sensors;
computer software is then used to determine the type and size of anomalies detected by the sensor.
MFL devices consist of several systems packaged into a single tool. At a minimum, an MFL tool
contains a magnetizing element, sensor, data recording, and power systems. MFL tools are usually
categorized as single piece or segmented. Single piece MFL tools contain all system components in  a
single rigid tool while segmented tools consist of multiple pieces joined to one another with flexible
connectors.
Inspection of pipelines via MFL detection involves the deployment of an MFL device through the
pipeline.  As the device moves through the pipeline, usually pushed by the product flowing through the
pipeline, the tool detects and records changes in magnetic flux. Traditional  MFL devices, also called
axial MFL, produce a magnetic field oriented along the axis of the pipe.  More recently, circumferential
MFL has been developed whereby the magnetic field is oriented  around the pipe, allowing for better
detection of axial defects such as cracks, seam weld defects, and  groove corrosion.
MFL inspection only works on conductive cast iron or steel pipelines. Most MFL applications are large,
and therefore only suited to larger diameter pipelines; however, some commercial applications have been
developed for use in smaller diameter pipelines.  Although MFL  is most commonly used to detect metal
loss, the technique can detect a variety of pipeline anomalies,  including circumferential and longitudinal
cracks. Newer, advanced MFL tools are additionally capable of producing accurate measurements of pipe
defects.
Given the widespread use of MFL technology in  the oil and gas industry, there are a variety of
commercial  MFL products available.  However, the technology has yet to gain acceptance in condition
assessment for wastewater collection systems.  The majority of MFL tools operate on the basic principles
outlined in the previous section.  The primary distinction between them is whether they use axial  or
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circumferential MFL, and the applicable diameter range.  Table 4-11 provides basic specifications on
available MFL tools.
Table 4-11: MFL Product Comparison
DEVICE
AES 19
AES ECAT
Axial Flaw Detection
(AFD) Tool
Corrosion Detection
Pig (CDP)
CPIG
LINSCAN
MagneScan
MAGPIE
MFL Inspection Tool
Pipesurvey MFL
TranScan
VECTRA
Vertiline /V-Line*
VENDOR
Advanced Engineering
Services
Advanced Engineering
Services
Rosen Inspection
Rosen Inspection
Baker Hughes
Lin Scan
GE Energy
TDW Services, Inc.
NGKS
Pipesurvey
International
GE Energy
BJ Services Company
Baker Hughes
TYPE
Circumferential
Axial
Circumferential
Axial
Axial
Axial
Axial
Axial
Axial
Axial
Circumferential
Circumferential
Axial
PIPE SIZE
3-in. to 12-in.
>12-in.
6 -in. to 5 6 -in.
6 -in. to 5 6 -in.
4-in. to 48-in.
6 -in. to 5 6 -in.
6 -in. to 5 6 -in.
4-in. to 42-in.
8-in. to 56-in.

12-in. to 3 6 -in.

2-in. to 36-in.
NOTE

Works externally







Bidirectional

Inertial navigation
Bidirectional
 *According to Baker Hughes, the Vertiline/V-line system is applicable for use in sewer lines.
4.4     Laser Profiling

Laser profiling generates a profile of a pipe's interior wall.  The technique involves using a laser to create
a line of light around the pipe wall.  For this reason, it is also called the lightline method. The laser light
highlights the shape of the sewer, allowing for the detection of changes to the pipe's shape, which may be
caused by deformation, corrosion, or siltation.  Laser inspection can only be used to inspect dry portions
of a pipe.  To assess the entire internal surface of a pipeline requires the pipe to be taken out of service.
Lasers are often used in combination with other inspection methods, most commonly CCTV and/or sonar.
Table 4-12 provides a summary description of the laser profiling technology.
Table 4-12: Laser Profiling Summary
SUMMARY
Sewer type
Material
Pipe size
Defects detected
Original application
Status
Advantages
Disadvantages
Gravity sewers, force mains.
Any
Product dependent
Deformations, siltation, corrosion,
Earlier use in large diameter tunnels and caverns
Commercially available
Provides better data quality then CCTV alone, can be used to create 3D
models of pipelines.
Can only detect defects above the water line.
Specific examples of laser profiling technologies are presented in the following section.
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Active 3D Laser Scanning -Redzone Robotics

RedZone Robotics offers the Active 3D Laser Scanning Attachment for its Responder Robotic platform.
This attachment creates a three dimensional model of the pipe, which allows for visualization of features
not visible by CCTV inspection. The attachment can be used to assess pipes ranging from 48-in. to 100-
in. in diameter, and requires a minimum 24-in. diameter manhole for deployment.  Inspections up to
5,500-ft. are standard while specialized configurations enable custom inspections of up to 14,000-ft.

Coolvision - Sima Environmental
Coolvision is an attachment for traditional CCTV systems. The laser system results in reports which
detail pipe grade and deflection. The system allows for the detection and measurement of cracks, as well
as the measurement of sediment, water depth, and service locations.

Laser Profiler - CUES

CUES offers the Laser Profiler as an attachment to the CUES CCTV system. The  attachment easily snaps
on to the system, and allows for the creation of reports which include measurements of sewer defects.
The attachment works by projecting a ring of light on the pipe's surface. The light is recorded by the
CCTV camera as the inspection is  conducted.  Software is used to analyze the laser ring and create a 3D
digital profile of the pipe. This can be done either from live or recorded video.  The profiler can be used
to detect and measure pipe size, ovality and capacity, laterals, water levels, and off-set joints, as well as to
collect survey data. The CUES laser attachment can be used to inspect pipes ranging from 6-in. to 72-in.
in diameter.

Laser Profiling Tool - Envirosight
Envirosight provides a laser profiling tool which can be used with either the ROWER or Supervision
crawlers and a CCTV camera.  The device can detect corrosion, cracks, debris,  pipe deformation, and
incorrect installation of liner.  The  tool can be used individually, or in combination with a sonar profiler to
inspect the pipe surface below the  flow line.  The tool can be used in pipes ranging from 4-in. to 160-in.
in diameter. The tool is used with  machine vision software, which uses data gathered from the CCTV
video to create a variety of reports, statistical analyses, and 2D or 3D models of the pipe.

Laser Profiler -R&R Visual
R&R Visual offers the Laser Profiler for inspection of dry gravity sewers.  The  tool works on pipes
ranging in sizes from 6-in. to 160-in. in diameter.  The device allows for accurate pipeline measurement,
measurement of sediment depth and volume. R&R Visual suggests utilizing this technology to assist in
soliciting accurate price quotes for pipeline cleaning in order to create cost savings for the utility owner.
The system works with R&R Visual proprietary software and Clearline software for 3D modeling.


4.5     Flow Meters

Flow meters (area-velocity meters) typically operate by direct measurement of depth and velocity. Flow
is then calculated based on the continuity equation. Metering devices referred to as "depth-only" or
"primary" metering devices calculate flow using weirs or flumes based on flow discharge relationship
equations.  These metering devices are limited for pipe reaches that do not surcharge.  Other "velocity-
only" metering devices function by measuring velocity in pipe sections that continually operate  under full
flow conditions.
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Communication with a flow meter can be achieved in the following manners: direct connection by laptop
in the field, telephone land lines, wireless digital telephone or internet technology, or radio frequency
networks. This includes communication through such technologies as general packet radio
service/enhanced data rates for global evolution (GPRS/EDGE); code division multiple access (CDMA);
mobile digital radio technology, including CDMA-1XRTT and CDMA-EVDO (evolution data
optimized). Although most meter data are collected with laptops in the field, wireless communication is
becoming the most popular method for new meters. Most wireless communication uses internet
technology. A major distinction between the communication approaches is whether each meter is
assigned a fixed internet protocol (IP) address or a floating IP address.  The floating IP address is the
easiest and least costly to deploy, but it also allows only one-way communication from the meter to the
host.  Communication with a fixed IP address occurs only when initiated by the meter.  Fixed IP
addresses allow the user to communicate with the meter for altering set up features, changing alarm setup
features and downloading new software. Many wireless carriers do not offer fixed IP addresses.
Real time communication is a very popular concept and is becoming widely used in wastewater treatment
plants. Implementing real time communication in  sewers is more difficult for two reasons. Most meters
operate by battery and frequent communication uses more energy than data collection does.  Energy use
for communication is high both for operating a modem with land lines and operating the radio frequency
equipment for wireless communication. Additionally, the term "real-time" in sewers is actually "near
time", because most meter measurements are in 5-minute or 15-minute collection frequencies, as many
operators prefer lower collection frequencies to achieve longer battery life.  Most metering technologies
relying on wireless communication operate in a one-way mode from the meter to the host. This strategy
is dictated primarily by the energy cost to "stay awake" for incoming communication.

The traditional view of real time data is from a Supervisory Control and Data Acquisition (SCADA)
perspective in which data are collected at a high frequency from many "dumb" sensors and a central
computer sorts and archives the data. This approach works  well for process control. An operator is
alerted to problems by the use  of "set points", such as a drop in dissolved oxygen level below a specified
concentration.  This may trigger an alarm condition requiring an operator response.  Real time data in
sewers have less value because there rarely are controllable processes in sewers, except for pump stations
and perhaps diversion gates.
Software for collecting and reporting flow monitoring data has evolved along with improvements in
communication protocols. Desk-top programs for analyzing flow data, performance monitoring, and
project reporting are being replaced  with web-based applications, which connect wirelessly to flow
monitors.  These software applications automate time-consuming tasks; making them more reliable and
cost-effective than traditional software programs. Additionally, some of the programs incorporate GIS
functionality, allowing users to integrate flow data with GIS models of the sewer system.


4.6    Innovative Technologies

Besides the range  of commercially available technologies for evaluation of wastewater systems and other
underground pipes, several other innovative technologies are currently under development. While the
following technologies are not currently commercially  available for condition assessment of wastewater
systems, they may be feasible methods of sewer assessment in the future.

4.6.1   Gamma-Gamma Logging

Gamma-gamma logging is a technique used primarily to evaluate cast-in-place concrete pilings and for
vertical borehole investigation in the mining and oil and gas industries. The technique involves the use of
a gamma-gamma probe, which consists of a source of gamma radiation such as cesium-137 and one or
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more gamma detectors. The detectors are shielded from direct radiation by a heavy metal such as lead.
The gamma-gamma probe emits photons which react to surrounding material based on density. The
photons are backscattered by the surrounding material, and data are recorded as a density log.  Inspection
using this technique is accomplished by raising and lowering the probe within a PVC inspection tube that
is inserted into the concrete piling or borehole. Results of the inspection yield information on the average
bulk density of the concrete. Properly constructed structures will have a consistent density.  The
technique can also be used to locate voids.
To date, gamma-gamma logging has not been used in pipeline inspection.  However, researchers at
Karlsruhe University in Germany performed laboratory tests that indicated a gamma-gamma probe could
be used to locate lateral connections and locate and measure the size of cavities in the bedding
surrounding a pipe.  The technology may be applicable for evaluating the overall condition of concrete
pipe or for detecting voids in bedding surrounding pipes. However, significant application issues would
exist in terms of training requirements and the tracking of the nuclear materials. These issues are faced by
the users of nuclear density gauges for soil compaction control.

4.6.2  Ground Penetrating Radar

The U.S. military originally developed ground penetrating radar (GPR) to  locate underground tunnels and
mines. GPR operates on the same principle as radar.  A transmitting antenna emits high-frequency radio
waves  into the ground.  The waves travel through the ground until they reach a material which has a
different conductivity and dielectric constant than the earth. The signal is  reflected and recorded by a
separate receiving antenna.  The amount of time it takes for the electromagnetic radio waves to be
reflected by subsurface materials can be analyzed to determine the position and depth of features below
the earth's surface.
There are a number of commercially available GPR systems. While some are designed to be used to
locate underground utilities, none is significantly used at present for pipeline inspection. GPR systems
that have been used to date in North America for internal pipe inspection could be considered more in the
prototype stage than in commercial use. However, since GPR can detect underground voids, it is
potentially useful for examination of pipe bedding. GPR can also potentially be used to locate leaks,
since saturated soil slows radio waves, resulting in a GPR profile showing a pipe deeper then would be
expected. Research into using GPR for sewer and bedding condition inspections is ongoing. Research
has already been conducted on its use for small diameter sewer lines and brick sewers.

4.6.3  Infrared Thermography

Infrared thermography (IRT) involves the use of an infrared camera to measure the temperature
differential across the surface of an object.  Software  can then be used to create an image displaying
different temperatures as different colors. This allows for the detection of the surface expression of
thermal conditions beneath the surface.  In this regard, it is a potential method of detecting sewer defects
such as leaks and voids, both of which can result in surface temperature variations when a sufficient
internal/external temperature difference exists.
Two basic methods of IRT are generally employed: passive IRT, which requires no external heat source;
and active IRT, which requires the use of a heat source such as an infrared tube light. Research into the
use of passive IRT to detect defects in and around subsurface pipelines has been conducted.  The method
has been demonstrated to be capable of detecting subsurface defects such as leaks, voids, and deteriorated
insulation.  Because the process is carried out from the surface, and the equipment used can scan a large
area quickly, the technology can be an efficient method for detecting pipe  defects. Active IRT has been
proposed as a method for pipeline assessment, but has not yet been evaluated.
                                            Page 4-44

 image: 






4.6.4  Micro-Deflection

Micro-deflection is a nondestructive technology used to evaluate brick, concrete, and clay structures. The
method involves the use of a load to create slight deformation, termed a micro-deflection, in the test
material. The change in position of the structure is measured, and a graph of load versus deflection is
created. Structurally sound test materials would be expected to have a consistent load versus deflection
graph, while deteriorated sections of the material would have a different value on the graph.
Although not a widespread method of evaluating wastewater pipes, micro-deflection has been used to
evaluate brick sewers. However, the usefulness of micro-deflection is limited, because the process can
only give a general understanding of pipe condition, such as the integrity of joints, rather than identifying
individual defects. In addition, plastics such as PVC and HDPE cannot be inspected using this method.

4.6.5  Impact Echo/Spectral Analysis of Surface Waves (SASW)

Impact Echo and SASW are two related techniques for evaluation of concrete and masonry. Both work
by subjecting a pipe to an elastic impact, produced by a device such as a pneumatic hammer, which then
propagates through the pipe.  The waves are reflected by internal flaws, as well as the surface of the
material, and the reflected waves are detected by an acoustic transducer such as a geophone located on the
exterior of the pipe. The technique can locate and measure cracks, delaminations, voids, and
honeycombing.

Impact Echo testing services are provided by several companies and its applicability for pipelines has
been researched. The Acoustic Impact Hammer, developed by the University of Karlsruhe in Germany,
uses a hammer to tap the inner surface of a pipe; laboratory trials resulted in the detection of cracks and
cavities around the pipe. A German technology which uses lasers to scan the response to impacts and
analyze them via SASW is available for tunnels and large pipes; however, this system requires entry into
the pipe and is therefore only suitable for very large pipes.

4.6.6   Ultrasonic Testing Systems

Several new ultrasonic-based testing systems are currently under development. Researchers at King's
College in London are developing a multi-sensor system termed the Ultrasonic-Based Inspection System
that can be integrated into existing CCTV inspection systems. This system automatically classifies data
based on an artificial neural network, and can detect very small cracks in the millimeter range. Research
into use of ultrasonic pulse velocity for the evaluation of concrete is being carried out at the University of
Waterloo in Canada.  Researchers at Pennsylvania State University are working to develop a sensor using
No-Contact Ultrasonic technology, which would be deployed into pipelines on a wheeled carriage.
                                            Page 4-45

 image: 






                              5.0    Technology Forum Summary
5.1    Background
A technology forum was held on September 11 and 12, 2008 in Edison, New Jersey to discuss the state of the
science for condition assessment of wastewater collection systems and to identify critical gaps in current
knowledge.  The white paper was distributed to participants in advance of the meeting and served as a basis for
forum discussions. The objective of the forum was to present the findings of the research and obtain direction for
additional research and further evaluation during the field demonstration tasks.  Figure 5-1 lists the presenters and
attendees at the Technology Forum.
WERF and other research institutions expressed interest in collaboration and sharing of research findings.  WERF
has completed twelve research projects related to condition assessment and rehabilitation of wastewater
infrastructure in the last ten years; these research reports can be found at www.werf.org. WERF's Condition
Assessment Protocols project, completed in 2007, provides guidance on developing and implementing a condition
assessment program, and includes an inventory of condition assessment tools and techniques.  On-going WERF
research includes development of decision support tools and implementation guidance for risk analysis, cost-
benefit, and estimation of residual life.  Virginia Tech is working on a WERF project to create the National
Database for Sustainable Water Infrastructure Management, with the objective of creating a web-based model that
can be used by utilities to determine information requirements for asset management decisions and support the
formal specification of data requirements.


5.2    General Discussion

The primary components of any asset management program include the identification, location and  condition of
assets; the determination of their useful life, and their valuation. Condition assessment provides the critical
information needed to determine the condition of each pipe within the system and its estimated time to failure or
remaining useful life. Critical gaps in the use of condition assessment as an asset management tool  include lack
of consistent, standard condition assessment protocols; methods for the systematic collection of data; and formal
risk assessment methods to prioritize resources for maintenance and or/rehabilitation activities.
Data needs for conducting condition assessment and making asset management decisions were discussed at the
Forum. It is important to define data needs so resources are spent wisely.  The level of data needed  for day-to-day
management is different than what is needed for making decisions on major rehabilitation. Some meeting
participants suggested that simple rules of thumb are adequate for making rehabilitation decisions (i.e., three or
more major defects per 250-300 foot pipe segment triggers rehab or replacement). It was agreed by the
participants that very detailed information is needed  for CMOM. Better data including historical information are
required for modeling. There is a concern that creating large databases for condition assessment data would be
overwhelming to utilities. There is added value from gathering extra data.  Information from a variety of
inspection tools should be used to make better decisions; CCTV is only one aspect of assessment and should not
be used in isolation.

Flow monitoring is an important tool in asset management.  In one case, pipes were going to be replaced at
tremendous cost, but flow monitoring data showed a restriction at a stream crossing was causing a backup; the
restriction was fixed, and overflows were reduced dramatically at a much lower cost. Flow assessment data can
be used to assess sewer condition and long-term system performance and to help calibrate models. Flow metering
data is traditionally used to generate hydrographs which provide information about water upstream of the meter.
Scattergraphs (displays of paired depth and velocity readings that look like  a pipe curve under normal flow
conditions), can reveal both upstream and downstream conditions, and can be used as verification of other
inspection data. Flow metering data may not be useful for predicting pipe failure.
The development and implementation of condition assessment programs was a topic of discussion. Most
condition assessment programs are currently focused on identifying and correcting I/I problems. A  question was
raised as to whether condition assessment should focus on other sewer defects in the future. Some utilities focus
on coding defects, but may not spend enough time on identifying and correcting problems. The condition

                                               Page 5-46

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assessment program should have a system-wide focus and not be limited to one aspect of the collection system
such as laterals or manholes.
An understanding of pipe failure mechanisms is needed to tailor a condition assessment program to the utility's
high priority needs and also to improve use of predictive models.  The United Kingdom has developed a
comprehensive database on wastewater utility assets and pipe failures that can be used to study pipe failure
mechanisms.  Pipe failure is dependent on many factors including the system design, installation, operation,
maintenance and inspection.  For example, system operating conditions (i.e. hydraulics, I/I) together with poor
maintenance practices may cause accumulation of sediment and other debris, resulting in sewage blockages,
overflows, increased hydrogen sulfide production and/or increased corrosion.  The main cause of failure in ferrous
force mains is internal corrosion whereas PCCP fails most often due to external corrosion.  Rehabilitated pipe
may fail at an accelerated rate depending on contractor experience, selection of rehab technology and the
understanding of baseline conditions. Many failures can be traced to human error.
There are many tools and risk assessment models for decision making related  to asset management,  ranging from
simple to complex. A question was raised as to whether utilities should use simple vs. complex tools.  A one-size
fits all approach does not seem appropriate. One tool that is needed is a branched decision-making tree based on
defect coding that can help prioritize areas for inspection. Decision making models are  used to assess  the
probability of failure and the consequences of failure. With accurate assessments of the probability  of failure and
the consequences of failure, cost-effective decisions can be made on risk mitigation. While the physical science is
good, the decision sciences are lagging.  Utilities often lack the input data for  pipe failure prediction models.
There is a need for belter decision making, and to improve on the general rules-of-thumb to make decision
making more cost effective.
A number of models related to risk-based pipe performance and condition assessment were presented and
discussed at the Forum:
       •   An on-going WERF project is developing a web-based model that can be used by utilities to
           determine information requirements for asset management decisions and support the formal
           specification of data requirements. The project is developing protocols and methods for predicting
           the remaining economic life of water and wastewater pipes, and developing a condition/performance
           index.
       •   Fuzzy logic  can be used for modeling pipe deterioration and to help make decisions on pipe renewal.
           Fuzzy mathematics provides an alternative in cases where pipe condition data are lacking.  It analyzes
           possibilities rather than probabilities of failure. The method was applied to large water transmission
           mains as part of an AwwaRF project.  Prototype software T-WARP is available on AwwaRF's
           website (AwwaRF Project No. 2883).
       •   CARE-S,  funded by the European Union, was designed as a proactive approach to develop methods
           and software that support efficient rehabilitation decisions. Failure codes developed as part of this
           project have been adopted by six  European countries to date. CARE-S can  be used for failure
           forecasting,  assessments of hydraulic performance and environmental impacts, and selection of
           rehabilitation technologies.
       •   A simple approach for condition assessment presented at the Forum taps into the  utility's extensive
           knowledge of the piping network rather than a comprehensive database of pipe information. The
           approach uses the utility's "beliefs" or observations about pipe condition to develop a criticality
           rating of likelihood and consequences of failure.  The approach is user friendly and does not require
           expert input. It can be applied using a simple computer program by utilities and their consultants.
           The approach was developed by a WERF-funded project, SCRAPS.


5.3    Critical Gaps  Identified in State of the Science

Critical gaps in our knowledge of inspection technologies, and our ability to diagnose and predict infrastructure
failures were  identified at the Technology Forum and are summarized below.
       1.  Research is needed to further define the costs and benefits of pipe inspection and rehabilitation as part
           of a utility's condition assessment program.  Methods of determining the impact of deteriorating
           collection systems on municipal budgets are needed.

                                               Page 5-47

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       2.  Inspection technologies need to be identified for the following applications:
             a.   Reduce use of confined space entry during sewer system inspections and investigations.
             b.   Affordable inspection technology that utilizes multi-sensor devices on a small transportable
                 package.
             c.   Inspecting pipes below the waterline.
             d.   Inspecting force mains that are in service.
             e.   Inspecting laterals.
       3.  Data management methods and models are available but a lack of standardization makes it difficult to
           compare historical data collected with different inspection technologies that have proprietary data
           structures.
       4.  Research is needed to improve how asset condition is tracked over time. Geospatial information
           (with a high degree of accuracy) needs to be collected along with pipe condition data in order to link
           historical inspection data with an exact physical location.
       5.  Information transfer to practitioners was identified as a critical industry need. Practitioners need
           training on topics such as infrastructure failure mechanisms; using historical inspection data for
           condition  assessment applications; applying the PACP coding system to characterize pipe defects;
           developing a condition assessment program; and preparing accurate record drawings for new and
           rehabilitated pipe. Practitioners need simple condition assessment tools (i.e. scattergraphs for
           analyzing flow data, decision trees, and rules of thumb).


5.4    Recommended Next Steps

Based on the Technology Forum discussions and findings, the project team has identified the following
technologies for possible inclusion in the project's field demonstrations:

       1.  Focused Electrode Leak Location System FELLS 41.
       2.  Ultra-wide band (UWB).
       3.  Laser (2D/3D).
       4.  Autonomous crawler technology.
       5.  Zoom Camera.
       6.  Digital scanning vs. CCTV.
       7.  Flow metering analysis as input to decision making tools to prioritize need for inspection.
       8.  Embedded sensors to monitor deflection, corrosion potential, and pressure.
                                                Page 5-48

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                                       PROJECT TEAM

The Cadmus Group        The Louis Berger Group          ADS                 RedZone Robotics
* Katharine Martel         LouRagozzino                  Pat Stevens           * Scott Thayer
Ralph Jones              * Christopher Feeney             Michael Bonomo      Brian Bannon
Chi Ho Sham             Samantha Hogan                * John Fortin-Independent Consultant
                                   TECHNOLOGY EXPERTS

*D. Thomas Iseley - Purdue University                *Lucio Soibelman - Carnegie Mellon University
Jeff Plymale - RJN Group                           *Raymond L. Sterling - Louisiana Tech
*Dan Murray - USEPA ORD                         *Tony Urquhart - MWH Global
*Roy Ramani - WERF                              *James Thomson -  Consultant
* Duncan Rose - GHD Consulting Inc.                 * Annie Vanrenterghem-Raven - NYU Polytechnic
*Sunil K. Sinha - Virginia Tech                       *Zack Zhao  - Ultraliner, Inc.
                                    US EPA PARTICIPANTS

Steve Allbee                       * Dennis Lai                        Ari Selvakumar
Richard Field                       *Dan Murray                       Anthony Tafuri
Evelyn Huertas                     Michael Royer                      Carlos Villafane
                                       STAKEHOLDERS

Steve Allbee - USEPA Office of Water
*Yehuda Kleiner - NRC Canada
Troy Norris - ASCE Pipeline Division
*Roy Ramani - Water Environment Research Foundation (WERF)
*Rod Thornhill - National Association of Sewer Service Companies (NASSCO)
Marty Umberg - National Association of Clean Water Agencies (NACWA)
Robert A. Villee - WEF Collection System Committee
                                  ADDITIONAL ATTENDEES

Wendy Condit - Battelle
George Kurz   - Barge Waggoner Sumner & Cannon
Robert Pennington - Camp Dresser & McKee Inc.
Lily Wang - Battelle
Dan Watts - New Jersey Institute of Technology

^Technology Forum Presenter


                             Figure 5-1: Technology Forum Attendees
                                            Page 5-49

 image: 






                                    6.0    References
American Concrete Institute. (2000). Service-Life Prediction: State- of-the-Art Report.  American
    Concrete Institute: Framington Hills, MI.

American Water Works Association Research Foundation (AwwaRF). (2005). Risk Management of
    Large-Diameter Water Transmission Mains. AwwaRF Project No. 2883. AwwaRF: Denver, CO.

Fleury, M.A. and Warner, J.  (2007).  Arizona's Largest Condition Assessment. Proceedings of WEF
    Collection Systems Specialty Conference, May 13-16, Portland, OR.

Marlow, D., Heart, S., Burn,  S., Urquhart, A., Gould, S., Anderson, M., Cook, S., Ambrose, M., Madin,
    B., and Fitzgerald, A. (2007). Condition Assessment Strategies and Protocols for Water and
    Wastewater Utility Assets. Water Environment Research Foundation (WERF): Alexandria, VA and
    IWA Publishing: London, United Kingdom.

McDonald, S.E. and Zhao, J.Q. 2001. Condition Assessment and Rehabilitation of Large Sewers. Report
    No. NRCC-44696. Institute for Research in Construction, National Research Council Canada:
    Ottawa, Canada

Merrill, M.S., Lukas, A., Palmer, R.N., and Hahn, M.A. (2004). Development of a Tool to Prioritize
    Sewer Inspections.  WERF: Alexandria, VA.

National Association of Sewer Service Companies (NAASCO). (2001). Pipeline Assessment And
    Certificate Program (PACP),v. 3.0. NASSCO: Owings Mills, MD.

Pressure Pipe Inspection Company, The. (n.d.).  The Remote Field Eddy Current / Transformer Coupling
    Technology (RFEC/TC).  Retrieved December 10, 2008 from
    http: //www .ppic. com/home/download .html

Rahman, S. and Vanier, D.J.  (2004). Municipal Infrastructure Investment Planning.  MIIP Report: An
    Evaluation of Condition Assessment Protocols for Sewer Management. Report No. B-5123.6,
    Institute for Research in Construction: Ottawa, Canada.

Thomson, J.C.  (2008). The Value of Inspection. Presented at:  STREAMS Task Order 59 Condition
    Assessment of Collection Systems Technology Forum. Sept. 11-12,2008. Edison, NJ.

Thomson, J.C., Hayward, P., Hazelden, G. Morrison, R.S., Sangster, T, Williams, D.S., Kopchynkski,
    R.K. (2004). An Examination of Innovative Methods used in the Inspection of Wastewater Systems.
    WERF: Alexandria, VA and IWA Publishing: London, United Kingdom.

U.S. Environmental Protection Agency (USEPA). (2002).  Clean  Water and Drinking Water
    Infrastructure Gap Analysis. Report No. USEPA-816-R-02-020, USEPA, Office of Water:
    Washington, District of Columbia.

USEPA. (2005). Guide for Evaluating Capacity, Management, Operation, and Maintenance (CMOM)
    Programs at Sanitary Sewer Collection Systems.  Report No. EPA-305-B-05-002, USEPA Office of
    Enforcement and Compliance Assurance: Washington, District of Columbia.
                                          Page 6-50

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USEPA.  (2007).  Innovation and Research for Water Infrastructure for the 21st Century Research Plan.
    Report No. EPA-ORD-NRMRL-CI-08-03-02, USEPA: Washington, District of Columbia.

Water Research Centre (WRc). (2003). Manual of Sewer Condition Assessment, 4th edition. WRc:
    Swindon, Wiltshire, United Kingdom.
                                         Page 6-51

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    Appendix A



Technology Vendors
      Page A-1

 image: 






                                  Camera Technologies
Digital Camera Inspection
Product(s)
Vendor/Address
Phone/Fax/Email/URL
DigiSewer
Envirosight
111 CanfieldAve.
Randolph, NJ 07869
Tel: (866) 936-8476
Fax:(973)252-1176
Email: through website
URL: http://www.envirosight.com
Panoramo
Rapidview-IBAK USA
1828 West Olson Road
Rochester, IN 46975
Tel: (800) 656-4225
Fax:  (574)224-5426
Email: info@rapidview.com
URL: http://www.rapidview .com
Sewer Scanning
Evaluation
Technology (SSET)
Hydromax USA, LLC
1766 Brent Drive
Newburgh, IN 47630
Tel: (812) 925-3930
Fax:(812)925-3911
Email: info@hydromaxusa.com
URL: http://www.hydromaxusa.com
Zoom Cameras
Product
Vendor/Address
Phone/Fax/Email/URL
AquaZoom
Aquadata, Inc.
95 5th Avenue
Pincourt, Quebec
Canada J7V 5K8
Tel: (800) 567-9003
Fax:(514)425-3506
Email: info@aquadata.com
URL: http://www.aquadata.com
Aries  HC3000 Zoom
Pole Camera
Aries Industries
550 Elizabeth St.
Waukesha,WI53186
Tel: (800)234-7205
Fax: (262) 896-7099
Email: through website
URL:  http://www.ariesind.com
Ca-Zoom PTZ

Quickview
GE  Sensing  &  Inspection
Technologies
721 Visions Drive
Skaneateles, NY 13152
Tel: (888)332-3848
Fax: (866) 899-4184
Email: through website
URL:
http://www.geinspectiontechnologies.com
CUES   IMX  Truck
Mounted      Zoom
Camera
CUES IMX Corporate Office
3 600 Rio Vista Ave.
Orlando, FL 32805
Tel: (800) 327-7791
Fax: (407) 425-1569
Email: salesinfo@cuesinc.com
URL: http://www.cuesinc.com
                                         PageA-2

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PortaZoom
CTZoom Technologies
2500 Boul. Des Enteprises #104
Terrebonne (Quebec)
Canada J6X4J8
Tel: (888) 965-8987
Fax: (450) 965-8987
Email: info@ctzoom.com
URL:  http://www.ctzoom.com
Push Cameras
Product(s)
Address
Phone/Fax/Email/URL
Insight Vision Push
Camera
Insight Vision
600 Dekora Woods Boulevard
Saukville, WI 53080
Tel: (800) 488-8177
Fax: (262) 268-9952
URL: http ://insightvisioncameras .com
Crystal Cam Push
Camera
Inuktun Services Ltd.
2569 Kenworth Road, Ste. C
Nanaimo, BC
Canada, V9T 3M4
Tel: (877) 468-5886
Fax: (250) 729-8080
Email:  sales@inuktun.com
URL:        http://www.inuktun.com/head-
office.htm
Flexiprobe
Pearpoint/RADIODETECTION
154 Portland Road
Bridgton, ME 04000
Tel: (877)247-3797
Fax: (207) 647-9495
Email: rd.sales.us@spx.com
URL: http://www .pearpoint.com
Hydrus, Orion,
Orion L
Rapidview-IBAK USA
1828 West Olson Road
Rochester, IN 46975
Tel: (800) 656-4225
Fax:  (574)224-5426
Email: info@rapidview.com
URL: http://www.rapidview.com
Lateral Launchers
Product(s)
Vendor/Address
Phone/Fax/Email/URL
LAMP
CUES IMX Corporate Office
3 600 Rio Vista Ave.
Orlando, FL 32805
Tel: (800) 327-7791
Fax: (407) 425-1569
Email: salesinfo@cuesinc.com
URL: www.cuesinc.com
Lateral Evaluation
Television System
Aries Industries
550 Elizabeth St.
Waukesha,WI53186
Tel: (800)234-7205
Fax: (262) 896-7099
URL:  http://www.ariesind.com
Lateral Inspection
System
RS Technical Services
1327 Clegg St.
Petaluma, CA 94954
Tel: (800) 767-1974
Fax: (707) 778-1974
URL:  http://www.rstechserv.com
                                         PageA-3

 image: 






IBAKLISY 150-M
      Rapidview-IBAK USA
      1828 West Olson Road
      Rochester, IN 46975
                             Tel: (800) 656-4225
                             Fax:  (574)224-5426
                             Email: info@rapidview.com
                             URL: http://www.rapidview.com
Small Diameter Tractors
Product(s)
      Address
                             Phone/Fax/Email/URL
ELKT100 Mini
      Pearpoint/RADIODETECTION
      154 Portland Road
      Bridgton, ME 04000
                             Tel:  (877)247-3797
                             Fax:  (207) 647-9495
                             Email: rd.sales.us@spx.com
                             URL: http://www .pearpoint.com
KRA65
      Rapidview-IBAK USA
      1828 West Olson Road
      Rochester, IN 46975
                             Tel: (800) 656-4225
                             Fax:  (574)224-5426
                             Email: info@rapidview.com
                             URL: http: //www. rapidview .com
Mighty
Transporter
Mini
RS Technical Services
1327 Clegg St.
Petaluma, CA 94954
Tel: (800) 767-1974
Fax: (707) 778-1974
URL:  http://www.rstechserv.com
Rower 100
      Envirosight
      111 CanfieldAve.
      Randolph, NJ 07869
                             Tel: (866) 936-8476
                             Fax:(973)252-1176
                             Email: through website
                             URL: http://www.envirosight.com
Versatrax 100
      Inuktun Services Ltd.
      2569 Kenworth Road, Ste. C
      Nanaimo, BC
      Canada, V9T 3M4
                             Tel: (877) 468-5886
                             Fax: (250) 729-8080
                             Email:  sales@inuktun.com
                             URL: http://www.inuktun.com/head-
                             office.htm
Xpress Silver-Bullet
Crawler
      Insight Vision
      600 Dekora Woods Boulevard
      Saukville, WI 53080
                             Tel: (800) 488-8177
                             Fax: (262) 268-9952
                             URL: http://insightvisioncameras.com
Long Range Tractors
Product
      Vendor/Address
                             Phone/Fax/Email/URL
Versatrax 300 VLR
      Inuktun Services Ltd.
      2569 Kenworth Road, Ste. C
      Nanaimo, BC
      Canada, V9T 3M4
                             Tel: (877) 468-5886
                             Fax: (250) 729-8080
                             Email:  sales@inuktun.com
                             URL: http://www.inuktun.com/head-
                             office .htm
                                         PageA-4

 image: 






Responder
Redzone Robotics
91 43rd St., Ste.250
Pittsburgh, PA 15201
Fax:(412)476-8981
Email:  through website
URL: http://www.redzone.com
                                  Acoustic Technologies
In-Line Leak Detectors
Product
Address
Phone/Fax/Email/URL
LxSentry
LxSix Photonics
520 McCaffrey St.
St-Laurent, Quebec
Canada H4T IN 1
Tel: (514) 599-5714
Fax:(514)599-5729
Email: info@lxsix.com
URL: http://www.lxsix.com
Sahara
Pressure    Pipe    Inspection
Company
1930 West Qual Avenue, Suite
A
Phenix, AZ 85027
Tel: (866)-990-2466
Email: info@ppic.com
URL: http://www.ppic.com
Smartball
Pure Technologies
Suite A, 9130 Red Branch Road
Columbia, Maryland 21045
Tel: 1-800-537-2806
Fax: (443) 766-7877
Email: through website
URL:  http://www.puretechnologiesltd.com
Acoustic Monitoring Systems
Product
AET
Soundprint AFO
Address
Pressure Pipe Inspection
Company
1930 West Qual Avenue, Suite
A
Phenix, AZ 85027
Pure Technologies
Suite A, 9130 Red Branch Road
Columbia, Maryland 21045
Phone/Fax/Email/URL
Tel: (866)-990-2466
Email: info@ppic.com
URL: http://www.ppic.com
Tel: 1-800-537-2806
Fax: (443) 766-7877
Email: through website
URL: http://www.puretechnoloaiesltd.com

Sonar/Ultrasonic
Product
Amtec Sonar
TISCIT
Address
Amtec Surveying Inc.
3355 Lenox Rd. Ste. 750
Atlanta, GA 30326
Phone/Fax/Email/URL
Tel: (404) 504-7044
Fax: (404) 504-7004
Email: info@amtecsurveving .com
URL: http://www.amtecsurveving.com
                                         PageA-5

 image: 






A-SIS
AquaCoustic
AquaCoustic Remote
Technologies, Inc.
3339 West 8th Ave.
Vancouver, BC
V6R 1Y3 Canada
Tel: (888)3749-7601
Fax: (604) 730-8771
Email: Info@AquaCoustic.com
URL: http://www.aquacoustic.com
Envirosight
Envirosight
111 CanfieldAve.
Randolph, NJ 07869
Tel: (866) 936-8476
Fax:(973)252-1176
Email: through website
URL: http://www.envirosight.com
PipeEye
PipeEye International
Unit 28 - 6275 Harrison Dr.,
Park 2000
Las Vegas, NV 89120
Tel: (888) 756-2033
Fax: (250) 753-2642
Email: info@pipeeyeinternational.com
URL: http://pipe-eve-int.com
RVS2
R&R Visual, Inc.
1828 West Olson Rd.
Rochester, In 46975
Tel: (800) 776-5653
Fax: (574)-223-7953
Email: support@seepipe .com
URL: http://www.expipeinspection.com
Sonar Profiler System
(submerged/semi-
submerged)
CUES Corporate Office
3600 Rio Vista Ave.
Orlando, FL 32805
Tel: (800) 327-7791
Fax: (407) 425-1569
Email: salesinfo@cuesinc.com
URL: www.cuesinc.com
Sonar Sewer Profiling
Attachment
Sonar Sweep
Attachment
Redzone Robotics
91 43rd St., Ste.250
Pittsburgh, PA 15201
Fax:(412)476-8981
Email - through website
URL: http://www.redzone.com
Ultrascan CD
Ultrascan DUO
Ultrascan WM
GE Inspection Technologies
50 Industrial Park Road
Lewistown, PA 17044
Tel: (866) 243-2638
Fax:(717)242-2606
URL:
http://www.geinspectiontecnologies.com
Inspector Systems
Ultrasonic Inspection
Robot
Aqua Drill International Inc.
1300 FM 545 East
Dickinson, TX 77539
Tel:  (281)337-0900
Fax:  (281)337-7270
URL: http://www.inspector-systtems.com
Wavemaker
Guided Ultrasonics Ltd.
30 Saville Road
Chiswick, London
W45HG
United Kingdom
Tel:+44 (0)20 8991 3771
Fax: +44 (0) 20 8987 0558
Email: info@guided-ultrasonics.com
URL:  http://www.guided-ultrasonics .com
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                         Electrical and Electromagnetic Products
 Electrical Leak Location Method
Product
Address
Phone/Fax/Email/URL
FELL-21
FELL-41
Metrotech Corporation
3251OlcottSt.
Santa Clara, CA 95054
Tel: (800) 446-3392
Fax:  (408)734-1415
Email: sales@metrotech.com
URL: http://www.feH21 .com
 Eddy Current and Remote Field Eddy Current
Product
Vendor/Address
Phone/Fax/Email/URL
BEM
Rock Solid Pry, Ltd.
11 Evans Str.
Burwood Vic 3124
Australia
Tel: (+613)9335-6122
Fax: (613)9335-6733
Email: info@rocksolidgroup.com.au
URL: http://www.rocksolidgroup.com.au
Hydroscope
Hydroscope Canada, Inc
8170 50 St. NW Suite 260
Edmonton, AB, T6B 1E6
Tel: (780)-450-6224
Fax: (780) 450-6224
Email: info@hydroscope.com
URL: http://www.hydroscope.com
See Snake Tool
CHECK IF VENDOR
Russel NDE Systems, Inc.
4909 75th Avenue
Edmonton, AB, Canada T6B
2S3
Tel: (780) 468-6800
Fax: (780) 462-9378
Email: info@russelltech.com
URL: http://www.russeltech.com
P-Wave
Pure Technologies
Suite A, 9130 Red Branch Road
Columbia, Maryland 21045
Tel: 1-800-537-2806
Fax: (443) 766-7877
Email: through website
URL:  http://www.puretechnologiesltd.com
RFEC/TC
Pressure Pipe Investigation
Company
                                                         info@ppic.com
                                                   http: //www .ppic. com/home/index.asp
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 Magnetic Flux Leakage
Product
Address
Phone/Fax/Email/URL
AES 19
AES ECAT
Advanced Engineering
Solutions, LTD
South Nelson Road
South Nelson Industrial Estate
Cramlington, Northumberland
NE23 1WF
United Kingdom
 Tel:+41 41 618 0300
 Fax:+41 41 618 0319
 Email: info@roseninspection.net
 URL: http ://www .aesengs .co.uk
Axial Flaw Detection
(AFD)

Corrosion Detection
Pig (CDP)
Rosen Inspection
Obere Spichermatt 14
6370 Stans
Switzerland
 Tel:+41 41 618 0300
 Fax:+41 41 618 0319
 Email: info@roseninspection.net
 URL: www.RosenInspection.net
CPIG
Vertiline/V-line, CPIG
Baker Hughes
12645 West Airport Blvd.
Sugar Land, TX 77478
 Tel: (281)276-5400
 Email:
 BPCebiz USA@bakerpetrolite.com
 URL: http://www.bakerhughesdirect.com
LINSCAN
LIN SCAN
205/206
Al Zahra Shopping Complex
U.A.E.
 Tel: +9716-7473600
 Fax: : +9716-7473800
 Email: Marketing@linscan.biz.
 URL: http://www.linscan.biz
MagneScan

TranScan
GE Energy
 URL:
 http: //www. gepower. com/contact/index.ht
 m
MAGPIE
TDW Services, Inc
4220 World Houston Pkwy,
Ste. 100
Houston, Texas 77032
 Tel: (832) 448-7221
 Email: Chuck.Harris@tdwilliamson.com
 URL: http://www.magpiesystems.com
MFL Inspection Tool
NGKS
7, Guilyarovsky St.
Moscow, Russia 129090
 Tel: +74959378636/26
 Fax:+ 7 495 937 86 35/31
 Email: khafizov@ngksint.com
 URL: http://www.ngksint.com
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Pipesurvey MFL
Pipesurvey International
Schrijnwerkersstraat 13
3334KHZwijndrecht
P.O.BOX 117
3330 AC Zwijndrecht
the Netherlands
 Tel+ 31 78610 1428
 Fax+ 31 78 610 2128
 Email: info@pipesurveyinternational.com
 URL:
 htto: //www .pipesurveyinternational. com
VECTRA
BJ Services Company
414 Pinckney
Houston, TX 77009
 Tel: (713) 224-1105
 Fax:(713)229-0541
 URL: http://www.biservices.com/
                                      Laser Products
Product
Address
Phone/Fax/Email/URL
Active 3D Laser
Scanning
Redzone Robotics
91 43rd St., Ste.250
Pittsburgh, PA 15201
Fax:(412)476-8981
Email: through website
URL: http://www.redzone.com
Coolvision
Sima Environmental
1153 EOgden, #705-135
Naperville, IL 60563
Phone: (630) 327-8503
Email: sima@wideopenwest.com
URL: http://www.simaenvironmental.com
Laser Profiler
CUES IMX Corporate Office
3 600 Rio Vista Ave.
Orlando, FL 32805
Tel: (800) 327-7791
Fax: (407) 425-1569
Email: salesinfo(g),cuesinc.com
URL: http://www.cuesinc.com
Laser Profiling Tool
Envirosight
111 CanfieldAve.
Randolph, NJ 07869
Tel: (866) 936-8476
Fax:(973)252-1176
Email: through website
URL: http://www.envirosight.com
Laser Profiler
R&R Visual, Inc.
1828 West Olson Rd.
Rochester, In 46975
Tel: (800) 776-5653
Fax: (574)-223-7953
Email: support(giseepipe.com
URL: http://www.expipeinspection.com
                                          PageA-9

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