United States
Environmental Protection
Agency
EPA/600/R-14/251 | January 2014 | www2.epa.gov/water-research
National Database Structure for
Life Cycle Performance
Assessment of Water and
Wastewater Rehabilitation
Technologies (Retrospective
Evaluation)
Office of Research and Development
Water Supply and Water Resources Division
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EPA/600/R-14/251
August 2014
National Database Structure for Life Cycle Performance
Assessment of Water and Wastewater Rehabilitation
Technologies (Retrospective Evaluation)
by
Erez Allouche, Ph.D., P.E., Shaurav Alam, Ph.D.,
and Ray Sterling, Ph.D., P.E.
Trenchless Technology Center at Louisiana Tech University
Wendy Condit, P.E. and John Matthews, Ph.D.
Battelle Memorial Institute
Contract No. EP-C-11-038
Task Order No. 1
Ariamalar Selvakumar, Ph.D., P.E.
Task Order Manager
U.S. Environmental Protection Agency
Urban Watershed Branch
National Risk Management Research Laboratory
Water Supply and Water Resources Division
Edison, NJ 08837
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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DISCLAIMER
The work reported in this document was funded by the U.S. Environmental Protection Agency (EPA)
under Task Order (TO) 1 of Scientific, Technical, Research, Engineering, and Modeling Support II
(STREAMS II) Contract No. EP-C-11-038 to Battelle. Through its Office of Research and Development,
EPA funded and managed, or partially funded and collaborated in, the research described herein. This
document has been subjected to the Agency's peer and administrative reviews and has been approved for
publication. Any opinions expressed in this report are those of the authors 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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ABSTRACT
This report builds upon a previous pilot study to document the in-service performance of trenchless pipe
rehabilitation techniques. The use of pipe rehabilitation and trenchless pipe replacement technologies has
increased over the past 30 to 40 years and represents an increasing proportion of the approximately $25
billion annual expenditure on the operation and maintenance of the nation's water and wastewater
infrastructure. This report describes the establishment of a database to house performance evaluation data
for rehabilitation technologies used in the water and wastewater sectors, carries out additional
retrospective evaluations of cured-in-place-pipe (CIPP) rehabilitation projects and begins the evaluation
of several fold-and-form, deform-reform, and sliplining projects. The new retrospective data for CIPP
and the testing of the other rehabilitation technologies are described in detail. The CIPP data are
combined with the pilot study data for an overall assessment of the current status of CIPP life cycle
performance. The potential uses of the database for data mining of key trends are demonstrated based
upon the CIPP technology performance data. The examination of CIPP liners with up to 34 years in
service and other rehabilitation technologies with up to 19 years of service has shown that all of the
rehabilitation technologies are showing little evidence of deterioration in service. The test results for 18
CIPP samples from nine cities across North America indicate that properly designed and installed CIPP
liners should meet and likely exceed the typical 50-year expected design life. For the fold-and-form,
deform-reform, and sliplining projects, there are only two to three samples per rehabilitation technology
and hence less can be said about overall performance. Nevertheless, all of the samples tested still met the
material property requirements at installations after 14 to 19 years of service. In summary, this provides
an excellent prognosis for the rehabilitation technologies on which the nation is depending.
in
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ACKNOWLEDGMENTS
This report has been prepared with input from the research team, which includes Battelle and the
Trenchless Technology Center (TTC) at Louisiana Tech University. The technical direction and
coordination for this project was provided by Dr. Ariamalar Selvakumar of EPA. The project team would
like to acknowledge several key contributors to this report in addition to the authors listed on the title
page. The project would not have been possible without the cooperation of the representatives of the
various cities and agencies that assisted in identifying appropriate sample locations and retrieving samples
for the study. These include: Mark Gehrke and Wayne Querry from the City of Denver; Siri Fernando
and Albert Kwan, City of Edmonton; Jason Iken, Greg Johnson, Joshua Kosmicki and Joe Smith, City of
Houston; Roger Hanas and John Morgan, City of Indianapolis; Rod Lovett and Ini Roberts, Miami-Dade
Water and Sewer Department; Greg Ballard, Hal Balthrop, Robby Ervin, Glenn Mizell and Paul
Stonecipher, City of Nashville; Dino Ng, City of New York; Jim Frantz, Ken Gardner, and Kelly Hamill,
City of Northbrook, IL; Chris Macey (AECOM) and Kas Zurek, City of Winnipeg. The city and
contractor crews who carefully excavated and/or cut samples are also to be thanked - excellent samples
were retrieved that safely made the journey to the TTC and Battelle laboratories for further study. These
include: Tim Carroll (TLCarroll Consulting Enterprises) and Bill King (Levi Contractors) in Denver;
Alex Sharpe (Insituform) in Indianapolis; Steve Cudd in Miami-Dade; Charlie Parker (Metro Wastewater)
in Nashville; Gene Camali (En-Tech) in New York. Thanks also go to Joe Barsoom, former Director of
the Sewer Division for the City and County of Denver, who assisted in the setup of the evaluations in
Denver. Others providing input to the project were: Richard Aillet, Bobby Booze, Craig Christians, Marc
Flatt, Roy Hughes, Dan Kvasnicka, Susan Marino, Ali Mustapha, James Redmond, Jorge Rivero, Dan
Shjandemaar, Kirk Skogen, James Theiler, Craig Weinland, and Eric Wharton. The authors would also
like to acknowledge research team participants who attended the sample retrievals and conducted the
laboratory testing. These include: Yu Yan, Tylor Baus, Ben Curry, Jake Pierce, Don Reuter, and Ryan
Stowe. The programmers for the database include Hrudaya Nath Kommareddy and Rajesh Kandepu.
Finally, the authors would like to thank Mr. Phil Zahrredine of Office of Wastewater Management and
Dr. Robert Brown of Urban Watershed Management Branch for their timely review of the research report.
IV
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EXECUTIVE SUMMARY
This report builds upon a previous pilot study to document the in-service performance of trenchless pipe
rehabilitation techniques (EPA, 2012). Use of pipe rehabilitation and trenchless pipe replacement
technologies has increased over the past 30 to 40 years and represents an increasing proportion of the
approximately $25 billion annual expenditure on the operation and maintenance of the nation's water and
wastewater infrastructure (EPA, 2002). Despite the massive public investment represented by the use of
these technologies, little formal and quantitative evaluation has been conducted on whether they are
performing as expected and whether rehabilitation is indeed cost-effective compared to replacement.
The major reasons for an interest in a retrospective evaluation of pipe rehabilitation systems are:
• The biggest data gap in asset management for pipeline systems involving rehabilitation is
prediction of the remaining asset life for the existing pipe and how long rehabilitation
techniques can extend that life. Municipalities have expressed a strong desire for data on the
current condition of previously installed systems to validate or correct the assumptions made
at the time of rehabilitation.
• Since several of the major pipe lining techniques have now been in use for at least 15 years
(some over 30 years in the U.S. and over 40 years internationally), it is a good time to
undertake such an investigation to assess whether the originally planned lifetime (typically
assumed to be 50 years) is reasonable based on the current condition of the liner.
It is not within the scope of this report to propose a new method to assess the longevity of pipe
rehabilitation liners and it is considered that the current level of data collected is insufficient to provide an
experimental basis for such a prediction that could cover the wide range of installation and use parameters
to which U.S. sewers are subjected. However, the data do provide important feedback on the current
condition of some of the older installations associated with each technology evaluated.
The initial project described in the previous report focused on CIPP liners because they were the first
trenchless liners (other than conventional slipliners) to be used in pipe rehabilitation and because they
hold the largest market share within relining technologies. The pilot testing used CIPP samples from both
large and small diameter sewers in two cities (EPA, 2012).
The current work takes up two of the recommendations from the prior work: to develop a database
structure for the exchange of performance information on rehabilitation technologies and to collect a
wider sample of physical test data and performance data on such technologies. In the current work, the
physical evaluation was extended to the use of CIPP in additional cities. A total of 13 new CIPP samples
from seven cities were added to the five CIPP samples from two cities tested in the pilot study. The 18
CIPP liner samples from both the current and the pilot study mostly ranged in age from 17 to 34 years,
while two younger liners (5 and 9 years) were also included. Samples of other types of rehabilitation
liners (two polyvinyl chloride [PVC] fold-and-form liners, three high density polyethylene [HDPE]
deform-reform liners, and two polyethylene slipliners) were also collected and tested.
Testing of the various liners over both projects included thickness, annular gap, ovality, specific gravity,
porosity, flexural strength, flexural modulus, tensile strength, tensile modulus, surface hardness, glass
transition temperature, Raman spectroscopy, environmental stress crack resistance and pipe stiffness as
appropriate to the liner type and condition.
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CIPP Rehabilitation Evaluation
The CIPP liners have specified minimum values for flexural modulus and flexural strength in American
Society for Testing and Materials (ASTM) F1216 and hence these are typically considered the key test
parameters for CIPP. The average flexural modulus values from each site for the new CIPP samples
retrieved ranged from 237,264 pounds per square inch (psi) to 477,609 psi. The mean and standard
deviation for the flexural modulus from all the new samples in the current study was 330,825 psi and
70,060 psi, respectively. Two out of the 13 average flexural modulus values fell below the ASTM
requirement of 250,000 psi, but there is no indication that these low values represent deterioration of the
liner as opposed to a poor liner quality in the as-installed liner.
The flexural strength values for the new CIPP samples ranged from 4,469 psi to 8,592 psi. The mean and
standard deviation of flexural strength from all the new samples in the current study was 6,682 psi and
1,211 psi, respectively. Only one of the average flexural strength values fell below the ASTM as-
installed requirement of 4,500 psi.
The strength and modulus values for all CIPP liners from both the current study and the pilot study are
plotted against the age of the liners in this report, but there is no obvious trend with age. This observation
is reinforced by a literature review (including two studies from the UK and Denmark involving
"retrieved" samples of the actual liner installation), in which the results show no consistent pattern of
change with age with some results increasing by modest amounts and others decreasing by modest
amounts. There are other data in the literature where installation sample tests are available for
comparison, but these samples do not have the same installation conditions as samples from the liner
installed within the host pipe.
The value of specific gravity and surface hardness for predicting the values of mechanical test parameters
was explored using the table of average values from each site and the full dataset of all test data. Despite
significant scatter in most of the relationships explored (only two of all the linear regressions plotted had
R2 correlation values above 0.50), there are visible trends of increasing flexural modulus, flexural strength
and tensile modulus with increasing specific gravity. There was, however, only a minor increase of
tensile strength observed with increasing specific gravity. A small increase in the Shore D hardness of the
inner and outer liner surfaces with increasing flexural modulus values was also seen. The inner hardness
showed a more pronounced relationship, but the scatter was large and the R2 values both very low.
A Web site has been created where the full database of retrospective test data is available for interested
parties to download so that users can carry out their own analyses of the data collected. Data are available
by sample or as aggregated data across all of the samples for a particular liner type. A number of
example plots using the Web site graphing functions are given in the main body of the report. The use of
the database to examine other potential relationships is explored in the report for the CIPP samples which
currently have more sites represented.
As part of the current project, a literature review was conducted to gain other insights and data from
similar studies being reported worldwide. This added to the information collected in an "international
scan" conducted in the pilot study. A number of cities worldwide have carried out some form of
evaluation of rehabilitation technology performance, but test data from such evaluations often are not
included in the literature. Overall, the experiences reported worldwide indicate that CIPP rehabilitation is
considered a reliable technique with a good track record. However, as a site-constructed lining process, a
number of defects can occur at the time of installation and these should be minimized.
The overarching conclusions from the study of the retrospective samples of CIPP lining are as follows:
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• The CIPP-lined sewers examined are holding up very well after their current in-service
exposures of 5 years to 34 years.
• While some defects were noted in the samples or the associated closed-circuit television
(CCTV) inspections, it is believed that most of these defects were created at the time of
installation and do not represent a degradation of the liner with time.
• In general, lining of a sewer pipe is only carried out when the existing host pipe has
experienced significant defects. For the sites studied, the CIPP lining has stabilized that
deterioration and is providing a continued service life for the pipe - and has done so without
the need for excavating and replacing the line from the surface.
• While the current dataset does not allow conclusions to be made about the average expected
lifetime of CIPP liners, it does appear that the original design life of 50 years expected by
most municipalities will be met and that much longer lifetimes can be achieved.
The above conclusions are not meant to imply that no CIPP liners will fail or have performance issues. A
number of quality/performance issues have been noted in this study and references are also provided in
the report to other studies that have assessed installation defects. These should be addressed in designs,
specifications and quality assurance/quality control (QA/QC) procedures to ensure that high quality liners
are installed.
Evaluation of Other Rehabilitation Technologies
The non-CIPP liners evaluated in this study comprised two PVC fold-and-form liners with 14 and 15
years of service, three HDPE deform-reform liners with 15 to 19 years of service, and two polyethylene
slipliners. One of the slipliners had 18 years of service and the other had an unknown installation date,
but is believed to be of a similar or older age. No test data from the time of installation were available for
any of the liner types.
For the PVC fold-and-form liners, the key parameters for evaluation are in terms of tensile strength,
tensile modulus, flexural strength and flexural modulus. For the HDPE deform-reform and polyethylene
slipliners, the key parameters for evaluation are in terms of density, flexural modulus, tensile strength and
environmental stress crack resistance (ESCR).
The average tensile strengths for the fold-and-form liners were 5,418 psi and 5,914 psi compared to the
as-installed required tensile strength from ASTM F1867 of 3,600 psi. The average (short-term) tensile
moduli for the fold-and-form liners were 288,335 and 314,873 psi compared to the minimum required in
ASTM F1867 of 155,000 psi. The average flexural strengths for the fold-and-form liners were 7,791 psi
and 8,581 psi compared to the as-installed required flexural strength from ASTM F1867 of 4,100 psi.
The average (short-term) flexural moduli for the fold-and-form liners were 273,471 and 279,551 psi
compared to the minimum required in ASTM F1867 of 145,000 psi. Both the tensile and flexural liner
properties after 14 and 15 years of service are well in excess of the required values at the time of
installation.
The average tensile strengths for the deform-reform liners ranged from 2,975 psi to 3,053 psi compared to
the minimum permissible values at installation of 2,600 psi for PE3408. The average (short-term) tensile
moduli ranged from 142,479 psi to 162,567 psi, but there is no corresponding requirement in the standard.
The average flexural strengths for the deform-reform liners ranged from 3,133 psi to 3,364 psi, but again
there is no corresponding requirement in the standard. The average (short-term) flexural moduli ranged
from 103,646 psi to 108,816 psi compared to the minimum value of 80,000 psi for PE3408. Hence, the
retrospective test values exceeded the as-installed requirements after 15 to 19 years of service.
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The average tensile strengths for the slipliners were 2,979 psi and 3,098 psi compared to the minimum
permissible values at installation of 2,600 psi for PE3408. The average (short-term) tensile moduli were
137,875 psi and 147,875 psi, but there is no corresponding requirement in the standard. The average
flexural strengths for the slipliners were 3,152 psi and 3,174 psi, but again there is no corresponding
requirement in the standard. The average (short-term) flexural moduli were 100,636 psi and 101,881 psi
compared to 80,000 psi for PE3408. As for the deform-reform HDPE liners, the installation test
parameters are all still satisfied at the current length of service.
The results of the other evaluation tests conducted on these liner types are provided in the report, but did
not indicate any distress or deterioration of these types of liners. Neither the fold-and-form nor the
deform-reform liners are currently marketed in the U.S. and sliplining is not often used in smaller
diameter sewers. This disappearance from the U.S. marketplace reflects both competitive pressures in the
marketplace and the tendency of both the fold-and-form and deform-reform liners to not be locked into
position longitudinally after installation (causing potential misalignment of lateral openings cut in the
liner). However, in terms of the retrospective evaluation of liner condition, these types of liners are all
performing well.
Future Research Activities
The following future research activities are recommended to further the current work to make the
conclusions more robust and to extend this type of study to other infrastructure systems.
• Continue to collect and test samples from additional sewerage systems in North America and
encourage municipalities and agencies to use opportunities where rehabilitated sections of
pipes or manholes are to be uncovered to include such collection and testing in their work.
• Extend the range of non-CIPP rehabilitation/renewal systems that are investigated for sewer
systems.
• Apply a similar methodology to gain an understanding of the performance of rehabilitation
systems for pressure pipes - both water distribution systems and sewer force mains.
• Expand the database by adding new data as they become available and encourage
municipalities to add their own test data to the database through administrative access
procedures with appropriate data vetting.
• Expand the qualitative technology performance information to provide much broader insights
into the issues experienced with a rehabilitation technology and the overall level of
satisfaction with the technology.
Overall Summary
The examination of CIPP liners with up to 34 years in service and other rehabilitation technologies with
up to 19 years of service has shown that all of the rehabilitation technologies are showing little evidence
of deterioration in service. The test results for 18 CIPP samples from nine cities across North America
indicate that properly designed and installed CIPP liners should meet and likely exceed the typical 50-
year design life that is expected. For the fold-and-form, deform-reform, and sliplining projects, there are
only two to three samples per rehabilitation technology and hence less can be said about overall
performance. Nevertheless, all of the samples tested still met the material property requirements at
installation after 14 to 19 years of service. In summary, this provides an excellent prognosis for the
rehabilitation technologies on which the nation is depending.
Vlll
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CONTENTS
DISCLAIMER ii
ABSTRACT iii
ACKNOWLEDGMENTS iv
EXECUTIVE SUMMARY v
APPENDICES xi
FIGURES xi
TABLES xii
ABBREVIATIONS AND ACRONYMS xiii
1 INTRODUCTION 1
1.1 Objective of This Study 1
1.2 Long-Term Goals of the Initiative 1
1.3 Prior Work in This Initiative 2
1.3.1 Evaluation of Samples from Denver and Columbus 2
1.3.2 Follow-on Work Recommended in the Pilot Study Report 3
1.3.3 Related U.S. and International Efforts 3
1.4 Organization of the Report 4
2 DATABASE DEVELOPMENT 5
2.1 Database Need and Value 5
2.2 Database Location and Accessibility 5
2.3 Database Overview 5
2.4 Database Content 9
2.5 Data Interpretation 11
2.6 Data Mining and Future Applications 16
3 REHABILITATION METHODS AND THE RETROSPECTIVE EVALUATION
PROCESS 17
3.1 Cured-in-Place Pipe Rehabilitation 17
3.1.1 Pipe Rehabilitation Process Using CIPP 18
3.2 Steps for the Retrospective Study of CIPP Liners 20
3.3 Testing and Measurement Protocols for CIPP Liners 21
3.4 Overview of Other Rehabilitation Technologies 21
3.4.1 Wastewater 21
3.4.2 Water 22
3.5 Other Technologies Considered for Evaluation in the Current Phase 23
3.6 Testing and Measurement Protocols for Fold-and-Form (PVC), Deform-Reform
(HOPE), and Sliplining 25
4 RELATED STUDIES OF CIPP PERFORMANCE 26
4.1 U.S. Studies 26
4.2 Canadian Studies 29
4.3 Summary of International Scan Findings in the Pilot Study 31
4.4 European Studies 32
4.5 Asian and Australian Studies 37
4.6 Summary 37
5 SUMMARY RESULTS AND COMMON THREADS 38
5.1 Current CIPP Case Studies 38
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5.1.1 Visual Inspection 39
5. .2 Annular Gap 39
5. .3 Soil and Pipe Sediment pH Values 40
5. .4 Liner Ovality 40
5. .5 Liner Thickness 41
5. .6 Specific Gravity 43
5. .7 Tensile Properties 43
5. .8 Flexural Properties 43
5. .9 Shore D Hardness 44
5. .10 Short-Term Buckling Tests 44
5. .11 Glass Transition Temperature 45
5.2 Synthesis of Current CIPP Data with Pilot Study Data 45
5.2.1 Flexural Properties 45
5.2.2 Tensile Properties 46
5.2.3 Specific Gravity 46
5.2.4 Shore D Hardness 46
5.2.5 Liner Thickness 47
5.2.6 Key Liner Properties versus Age of Liner 47
5.2.7 Strength and Modulus Properties versus Specific Gravity 51
5.2.8 Relationships among the Strength and Modulus Parameters 51
5.2.9 Evaluations of Shore D Hardness Relationship to Other Parameters 54
5.2.10 Flexural Modulus of a Liner Compared to Liner Variations 56
5.2.11 Summary of Results from Liner Testing at Different Ages 58
5.3 Examples of Exploration of Relationships for CIPP Liners Using the Database 59
5.3.1 Exploring the Potential for the Database 60
5.3.2 Exploration of 2-D Scatter Plot Data Relationships 60
5.3.3 Database Mean Value Plots 66
5.3.4 Summary for Database 67
5.4 Other Rehabilitation Technologies 67
5.4.1 Sample Sites and Key Test Parameters 68
5.4.1.1 PVC Fold and Form Standards 68
5.4.1.2 HOPE Deform-Reform Standards 68
5.4.1.3 Polyethylene Sliplining Standards 68
5.4.2 Summary of Results for Other Rehabilitation Technologies 68
5.4.2.1 Visual Inspection 70
5.4.2.2 Annular Gap 70
5.4.2.3 Soil and Pipe Sediment pH Values 70
5.4.2.4 Liner Ovality 70
5.4.3 Liner Thickness 71
5.4.4 Specific Gravity 72
5.4.5 Tensile Properties 72
5.4.6 Flexural Properties 72
5.4.7 Shore D Hardness 73
5.4.8 Pipe Stiffness 73
6 CONCLUSIONS AND RECOMMENDATIONS 74
6.1 Conclusions 74
6.1.1 Overall Observations for CIPP 74
6.1.2 Overall Observations for the Other Rehabilitation Technologies Tested 75
6.1.3 Some Common Threads 75
6.1.3.1 Lack of Historic Records for Rehabilitation Work 75
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6.1.3.2 Quality Control in Installation 75
6.1.3.3 Usefulness of Various Test Parameters 76
6.2 Recommendations 77
6.2.1 Future Research Needs 77
6.2.2 Recommendations for Agencies and Municipalities 77
7 REFERENCES 79
APPENDICES
Appendix A: Test Protocols
Appendix B: CIPP Case Studies
Appendix C: Studies for Other Rehabilitation Technologies
Appendix D: Qualitative Observations Concerning Wastewater Rehabilitation Performance
Appendix E: Relevant ASTM Standards
FIGURES
Figure 2-1. Home Page of the Database Web Site 6
Figure 2-2. Rehabilitation Technology Methods Included in the Database 7
Figure 2-3. Retrospective Case Studies Included in the Database 8
Figure 2-4. Rehab Analytics Mean Value Plot for Flexural Strength of CIPP Samples 9
Figure 2-5. RehabAnalytics 2-D Plot of CIPP Flexural Strength versus Tensile Strength 9
Figure 2-6. Raw and Synthetically-Generated Tensile Modulus Values 14
Figure 2-7. RehabAnalytics Generation of Synthesized Values in the Database 15
Figure 2-8. No Synthetic Values (left) and 100 Synthetic Values (right) forHOU-21-1996 15
Figure 3-1. Summary of Common CIPP Technologies 17
Figure 3 -2. CIPP Installation Options: Liner Pull-in (left) and Liner Inversion (right) 20
Figure 3-3. Summary of Trenchless Sewer Rehabilitation Technologies 22
Figure 3-4. Rehabilitation Approaches for Water Mains 23
Figure 5-1. Flexural and Tensile Moduli versus Age of Liner 50
Figure 5-2. Flexural and Tensile Strengths versus Age of Liner 50
Figure 5-3. Specific Gravity of Liner versus Age of Liner 51
Figure 5-4. Flexural Strength and Tensile Strength versus Specific Gravity 52
Figure 5-5. Flexural Modulus and Tensile Modulus versus Specific Gravity 52
Figure 5-6. Tensile Modulus versus Tensile Strength 53
Figure 5-7. Flexural Strength versus Tensile Strength 53
Figure 5-8. Tensile Modulus versus Flexural Modulus 54
Figure 5 -9. Flexural Strength and Tensile Strength versus Flexural Modulus 54
Figure 5-10. Shore D Hardness versus Flexural Modulus 55
Figure 5-11. Shore D Hardness of Inner Liner Surface versus Age of Liner 56
Figure 5-12. Hardness Difference Outer-Inner Liner Surface versus Age of Liner 56
Figure 5-13. Flexural Modulus versus Variation in Surface Hardness 57
Figure 5-14. Flexural Modulus versus Thickness Variation from Specified Value 57
Figure 5-15. Web Site Plot of Flexural Modulus versus Tensile Strength 60
Figure 5-16. Web Site Plot of Flexural Modulus versus Tensile Strength for NYC-15 Sample 61
Figure 5-17. Web Site Plot of Flexural Modulus versus Tensile Strength with Trend Line for
NYC-15 Sample 61
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Figure 5-18. Web Site Plot of Flexural Modulus versus Flexural Strength 62
Figure 5-19. Web Site Plot of Flexural Modulus versus Specific Gravity for All CIPP Sites 63
Figure 5-20. Web Site Plot of Flexural Modulus versus Density (100 Synthetic Values) for All
CIPP Sites 63
Figure 5-21. Web Site Plot of Flexural Modulus versus Inner Surface Hardness (No Synthetic
Values) for All CIPP Sites 64
Figure 5-22. Web Site Plot of Flexural Modulus versus Inner Surface Hardness (100 Synthetic
Values) for All CIPP Sites 64
Figure 5-23. Web Site Plot of Flexural Modulus versus Inner Surface Hardness for Indianapolis 65
Figure 5-24. Web Site Plot of Flexural Modulus versus Inner Surface Hardness forNYC-15 65
Figure 5-25. Web Site Bar Chart for Mean Values of Flexural Modulus 66
Figure 5-26. Web Site Bar Chart for Mean Values of Flexural Strength 66
Figure 5-27. Web Site Bar Chart for Mean Values of Liner Specific Gravity 67
TABLES
Table 2-1. Retrospective Test Parameters in the Database 10
Table 2-2. Site Background Information Listed in the Database 10
Table 2-3. Updatable Test Data for Particular Samples 11
Table 2-4. Synthesis of Additional Tensile Modulus Values for Plotting Purposes (Part 1) 13
Table 2-5. Synthesis of Additional Tensile Modulus Values for Plotting Purposes (Part 2) 14
Table 3-1. Key ASTM Standards Covering CIPP Installations 19
Table 3-2. Key ASTM Standards Covering Fold-and-Form (PVC), Deform-Reform (HOPE),
and Sliplining 25
Table 4-1. IKT Test Results for Wall Thickness 26
Table 4-2. City of Winnipeg Test Results for 34-Year Old CIPP Liners 29
Table 4-3. Retrospective Test Data from Quebec 30
Table 4-4. Retrospective Liner Sampling in Denmark 32
Table 4-5. Application of Quality Parameters and Test Standards 34
Table 4-6. Three-Point Flexural Test Data (ISO 178) 34
Table 4-7. Average Water Absorption (ISO 62) and Density 34
Table 5-1. Summary of Key Laboratory Test Results from Current Case Studies 38
Table 5-2. Annular Gap Observations for the Current Case Studies 39
Table 5-3. Measurements of pH forthe Current Case Studies 40
Table 5-4. Measured Liner Ovality forthe Current Case Studies 42
Table 5-5. Measured and Specified Liner Thickness forthe Current Case Studies 42
Table 5-6. Short-Term Buckling Test Results forthe Current Case Studies 44
Table 5-7. Average Glass Transition Temperature forthe Current Case Studies 45
Table 5-8. Measured and Calculated Average Test Parameters forthe 18 Retrospective
Samples 49
Table 5-9. Comparison of Northbrook, Illinois Retrospective Data 59
Table 5-10. Summary of Key Laboratory Test Results for Other Rehabilitation Technologies 69
Table 5-11. Annular Gap Observations for Other Rehabilitation Technologies 70
Table 5-12. Measurements of pHfor Other Rehabilitation Technologies 70
Table 5-13. Measured Liner Ovality for Other Rehabilitation Technologies 71
Table 5-14. Measured and Specified Liner Thickness for Other Rehabilitation Technologies 71
Table 5-15. Pipe Stiffness for Other Rehabilitation Technologies 73
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ABBREVIATIONS AND ACRONYMS
2-D
3-D
two-dimensional
three-dimensional
ASTM American Society for Testing and Materials
CCTV closed-circuit television
CIPP cured-in-place pipe
DR standard dimension ratio for a pipe (= outside diameter + thickness)
D-R deform-reform method of pipe rehabilitation using HOPE
DSC differential scanning calorimetry
EPA U.S. Environmental Protection Agency
EPAD elevated pressure application device
ESCR environmental stress crack resistance
F&F fold-and-form method of pipe rehabilitation using PVC
HOPE high density polyethylene
I/I infiltration and inflow
IKT Institut fur Unterirdische Infrastruktur GmbH (Institute for Underground Infrastructure)
ISTT International Society for Trenchless Technology
LVDT linear variable displacement transducer
MSE mean squared error
NASTT North American Society for Trenchless Technology
NOT non-destructive testing
NRMRL National Risk Management Research Laboratory
PE polyethylene
psi pounds per square inch
PUB Public Utilities Board (Singapore)
PVC polyvinyl chloride
QA quality assurance
QAPP Quality Assurance Protocol Plan
QC quality control
RPD relative percent difference
Tg glass transition temperature
TO task order
TTC Trenchless Technology Center
UTM Universal Testing Machine
UV ultraviolet
Xlll
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INTRODUCTION
This report presents the results of continued work to understand and document the performance of pipe
rehabilitation technologies. The project has been funded by the U.S. Environmental Protection Agency
(EPA) as part of a broader initiative to study and support technology development for the rehabilitation of
water distribution and wastewater collection systems. Use of trenchless pipe rehabilitation and pipe
replacement technologies has increased over the past 30 to 40 years and represents an increasing
proportion of the approximately $25 billion annual expenditure on the operation and maintenance of the
nation's water and wastewater infrastructure (EPA, 2002). Prior to this initiative and despite the massive
public investment represented by the use of these technologies, little formal and quantitative evaluation in
the U.S. has been conducted on whether or not the pipes were performing as expected and if rehabilitation
was indeed cost-effective compared to replacement. An initial pilot study was funded under EPA's Aging
Water Infrastructure Research Program for the development of a sample recovery and testing protocol
together with the recovery and extensive testing of four samples of cured-in-place pipe (CIPP) liners from
two participating cities (EPA, 2012). This research expanded upon the initial efforts by: collecting more
CIPP samples, collecting retrospective evaluation samples for additional rehabilitation technologies (e.g.,
other than CIPP), and developing the structure for a national database on the performance of trenchless
rehabilitation technologies. This report presents the results from building a database to document the
performance of rehabilitation technologies on a national basis including additional CIPP liner testing,
testing of three other types of rehabilitation technologies (sliplining, fold-and-form, and deform-reform),
and a review of the overall experiences with sewer rehabilitation technologies.
This research was conducted for the EPA National Risk Management Research Laboratory (NRMRL)
under Task Order (TO) No. 01 titled Field Demonstration and Retrospective Evaluation of Rehabilitation
Technologies for Wastewater Collection and Water Distribution Systems of the Scientific, Technical,
Research, Engineering, and Modeling Support II (STREAMS II) Contract No. EP-C-11-038. The
research team for the retrospective evaluation was a collaborative effort between Battelle and the
Trenchless Technology Center (TTC) at Louisiana Tech University. TTC carried out the liner testing and
developed the database and data mining approaches.
1.1 Objective of This Study
The objective of this study was to create a database of performance results for technologies used in the
rehabilitation of gravity sewers, along with the means for interpreting the results through data mining
techniques. This objective has included extending the number of sites contributing physical testing data
from older in-service liner technologies and capturing broader qualitative data from the agencies that
participated in the study.
1.2 Long-Term Goals of the Initiative
As discussed in the prior report, the major reasons for interest in a retrospective evaluation of pipe
rehabilitation systems are that:
• The biggest data gap in asset management for pipeline systems involving rehabilitation is
prediction of the remaining asset life for the existing pipe and how long rehabilitation
techniques can extend that life. Municipalities have expressed a strong desire for data on the
current condition of previously installed systems to validate or correct the assumptions made
at the time of rehabilitation.
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• Since several of the major pipe lining techniques have now been in use for at least 15 years
(some over 30 years in the U.S. and over 40 years internationally), it is a good time to
undertake such an investigation to assess whether the originally planned lifetime (typically
assumed to be 50 years) is reasonable based on the current condition of the liner.
• A valuable outcome would be to address one of the largest unknowns in terms of decision-
making for engineers carrying out life cycle cost/benefit evaluations.
This type of evaluation can provide answers to the question "How long can I extend the life of the asset if
I rehabilitate it instead of replacing it?" but can also start to fill one of the biggest gaps in knowledge
about rehabilitation technologies that exists today - their expected lifetimes under a variety of installation
and service conditions. Evaluating rehabilitation technologies that have already been in service for a
significant length of time can provide data that could be used immediately by other municipalities (e.g.,
what properties/defects are critical; what accelerates deterioration) and can establish benchmarks for
vendors against which they can improve their products (i.e., it could become a driver for achieving
excellence).
1.3 Prior Work in This Initiative
The initial pilot study described in an earlier report (EPA, 2012) focused on CIPP liners because they
were the first trenchless liners (other than conventional slipliners) to be used in pipe rehabilitation and
because they hold the largest market share within relining technologies. The pilot testing used CIPP
samples from both large and small diameter sewers in two cities: Denver, CO and Columbus, OH. For
the small diameter (8 in.) sewers in each city, a 6 ft section of pipe and liner was exhumed. For the larger
diameter sewers (36 to 48 in. diameter), CIPP liner samples were cut from the interior of the pipe and the
liner was patched in situ.
The pilot study report provided a detailed description of the CIPP process, its use in the U.S. and an
international scan of the approaches to sewer rehabilitation in other cities worldwide. The development
of the sample retrieval and testing protocols used for the retrospective study was also described. Testing
on the liners included thickness, annular gap, ovality, density, specific gravity, porosity, flexural strength,
flexural modulus, tensile strength, tensile modulus, surface hardness, glass transition temperature, and
Raman spectroscopy. In addition, environmental data were gathered as appropriate to each retrieval
process including: external soil conditions and internal waste stream pH. The findings from the testing
were presented in detail in the report and a short overall summary of the pilot study findings and the
information gathered from the international scan is given below (EPA, 2012).
The pilot study activities also produced several review reports on the state of technology for water and
wastewater rehabilitation (EPA, 2009, 2010, 2013).
1.3.1 Evaluation of Samples from Denver and Columbus. All of the samples retrieved from the
four locations involved in the pilot study testing were in excellent condition after being in use for 25
years, 23 years, 21 years, and 5 years, respectively. Three of these liners had already been in service for
approximately half of their originally expected service life. Two samples had a flexural modulus value
that was lower than the originally specified value, but this could not be tied directly to deterioration of the
liner over time. In the case of the Denver 48-in. downstream liner, in particular, it appeared likely that the
poor physical test properties may have resulted from variability within the liner rather than a change over
time. Some indication of a softening of the interior surface of the linerthat was exposed most to the
waste stream (interior invert and spring lines) relative to the interior crown location and that of the
exterior surface of the liner was noted in surface hardness testing. However, it is not yet possible to
isolate any effect on the resin liner itself from the hydrolysis of the handling layer that was originally
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present on the inside surface of the CIPP liner. For newer CIPP liners, a different handling/inner layer
with greater durability is used, but it is still a softer material than the CIPP resin itself.
In Denver, a few specific defects were noted at different locations in closed-circuit television (CCTV)
inspections of nearly 5,800 ft of CIPP liners installed at the same time as the retrieved sample. Most of
these were related to poor practices in cutting or reinstating lateral connections and only three appeared
potentially unrelated to lateral reinstatement issues. These were a local liner bulge, a separation of the
liner from the wall of the pipe, and a local tear in the liner.
Overall, there was no reason to anticipate that the liners evaluated in the pilot study would not last for
their intended lifetime of 50 years and perhaps well beyond.
1.3.2 Follow-on Work Recommended in the Pilot Study Report. Given the insights provided by
the pilot studies in Denver and Columbus, an expansion of the retrospective evaluation study was
recommended to create a broader national database that would help to better define the expected life of
sewer rehabilitation technologies. Specifically, it was recommended that the pilot studies and
retrospective evaluation program be extended to cover the following activities:
• Additional CIPP sample retrieval in other cities with a wider variety of site and sewage flow
characteristics.
• Pilot studies of other sewer rehabilitation technologies, focusing initially on those with the
greatest number of years of service. As with the current CIPP study, the pilot study would
seek to identify the most useful quantitative tests that could be used to evaluate performance,
degradation, and expected remaining life.
• A broader review of the locally interpreted data from cities participating in the study on their
experiences with rehabilitation technologies.
• An effort to encourage sewer agencies to keep as-installed material test data for later
comparison with follow-up testing. This should include working with the most widely used
database and asset management systems to make sure that such information can readily be
incorporated and identified using their software.
• Adaptation, development, and/or calibration of non-destructive testing (NOT) methods, plus
similar efforts for material test methods that could use small physical samples that are easily
retrieved robotically from inside the pipe and for which the damage could be easily repaired.
Several quantitative liner characterization tests that could be expected to be developed for
robotic deployment within sewer mainlines of 8-in. diameter and larger have been identified
as part of this project.
The current work takes up two of the recommendations from the prior work: to develop a database
structure for the sharing of performance information on rehabilitation technologies and to collect a wider
sample of physical test data and experiential data on such technologies. The results of the pilot study
testing and the findings of related studies by others are considered, along with the new evaluations in
Section 5 of this report.
1.3.3 Related U.S. and International Efforts. A comprehensive literature review was conducted
to summarize information from recent studies of CIPP technology performance. In addition, the
international scan undertaken in the pilot study provided some insight into the experiences of a wide
range of utilities that have embarked on significant CIPP rehabilitation programs over past decades. The
purpose was to assess internationally-based utilities' views on the effectiveness of CIPP rehabilitation and
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to document any efforts to evaluate and/or monitor the installed quality of their CIPP installations over
the long term. The information collected pointed to a number of efforts being made internationally to
evaluate the performance of CIPP rehabilitation of gravity sewers in the UK, France, Germany,
Singapore, Australia, Japan, and Canada. Information identified relative to CIPP performance and
longevity is summarized in Section 4, which addresses key findings from recent studies and this research.
1.4 Organization of the Report
The remainder of the report is organized into the following sections:
• Section 2 Database Development. Section 2 describes development of the database for
retrospective evaluation data, its user interface, and data mining approaches.
• Section 3 Rehabilitation Methods and the Retrospective Evaluation Process. Section 3
introduces the CIPP process and gives an overview of other rehabilitation technologies. The
retrospective evaluation process for the collection and testing of physical samples of CIPP
liners and other rehabilitation technologies is described.
• Section 4 Related Studies of CIPP Performance. Section 4 identifies and summarizes
information from related recent studies of CIPP quality control (QC) and in-service
performance that have been reported in the literature.
• Section 5 Summary Results and Common Threads. Section 5 provides an integrated
discussion of the long-term performance of CIPP and the other rehabilitation technologies
from all of the information collected by the study to date. It also illustrates potential uses of
the database by exploring the CIPP data relationships.
• Section 6 Conclusions and Recommendations. Section 6 provides the conclusions from the
current work and recommendations for the focus of ongoing studies.
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DATABASE DEVELOPMENT
2.1 Database Need and Value
This section describes the creation of a database to assemble the test results from the retrospective
evaluation study for sewer rehabilitation technologies. A review of insights and data visualizations that
can come from the database are presented in Section 5.3 of this report.
The pilot study on retrospective evaluation (EPA, 2012) and the continued evaluation work described in
this report have highlighted the importance of understanding the performance of rehabilitation
technologies that have been installed over the past 30 plus years. In order to be able to analyze the data
being collected (either individually by municipality or across sites) and make it as useful as possible to
cities and industries working to improve performance, there needs to be a structure for organizing the
data, analyzing the data in different ways, and inputting new data as more are collected. The database
developed in this phase of the project provides a platform for such analyses and allows for potential
correlations to be explored across any of the test data collected for the liners.
2.2 Database Location and Accessibility
The database is currently being maintained and housed on a TTC server. It is accessible through the
following Web link: http://138.47.78.37/Retrospective. The database has been made available online
through a Web site constructed using Microsoft ASP.Net technology with C#.Net and the database
software is MYSQL. Provisions have been made for both user login and administrative login accounts. In
addition, a registration option is also available for new users. The user is asked to provide the following
information to register: Name, Organization, and Role. The user also provides their e-mail address,
proposed user name, and password. An automated e-mail will then follow from the Administrator to the
new user once a request for the opening of an account has been received. Once accepted by the
administrator, users are asked to provide their user name and password to access the site. Administrative
access is open to the database development and maintenance team only with limited access granted to
agencies that are able to contribute data.
2.3 Database Overview
After successful login, the user will be directed to the home page where a brief description of the project
is given. As shown in Figure 2-1, the Web site housing the database consists of the following Web pages:
• Home Page,
• Research Page,
• Team Page,
• Methods Page,
• Case Studies Page,
• RehabAnalytics,
• Submit, and
• Account Profile/Login.
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»^ Trenchless Technology Center
Louisiana Tech University
&EPA
Baireiie
Research Team Metho<
Profile Logout
Trenchiess rehabilitation technologies have been steadily increasing in use ever the past 30 years and represent an increasing proportion of the annual operation and
maintenance expenditures for the nation's water and wastewater infrastructure. Despite public investment in use of these technologies, there has been little quantitative
evaluation of how these technologies are performing over the long-term. The goal of the U.S. Environmental Protection Agency (EPA) retrospective evaluation research is to
provide improved information to utilities oc the life-cycle performance of various rehabilitation technologies.
This Web site serves as a readily accessible tool for stakeholders to share their experience and data on long-term trenchless technology performance for water
distribution and ivasteivater collection systems. The main component of this project has been a retrospective evaluation of the long-term performance of wastewater
technologies now that some have been installed for more than half of their target life cycle.
Disclaimer: This database has been subjected to the Agency's peer and administrative revise's and has bsen approved for publication. Any opinions expressed ore those of
ike authors and do not necessarily reflect the \iews of the Agency: therefore, no official endorsement should be irtferred. Any mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
Figure 2-1. Home Page of the Database Web Site
Under the Research Web page, the overall research objectives for the retrospective study are explained,
along with information about the database. The participants on the research team from Battelle Memorial
Institute and the TTC, Louisiana Tech University are presented under the Team Web page, along with
acknowledgments of the participating cities.
Separate tabs for Water and Wastewater technologies are provided under the Methods Web Page (see
Figure 2-2). Under the Wastewater tab, the various sewer rehabilitation methods included are outlined and
links are provided to the specific case studies providing data for each of the four rehabilitation methods -
CIPP, deform-reform, fold-and-form, and sliplining - that are a part of the database structure. The Water
rehabilitation technology tab is provided for the potential extension of the database to include the
rehabilitation of water distribution systems.
Retrospective evaluation specimens were collected from different physical locations across North
America. In the Case Studies tab, access to information and data about the rehabilitation case studies is
provided (see Figure 2-3). The data related to each sample were labelled following the naming scheme
"Name of the City - Diameter of the Host Pipe - Year of Installation." For example, NYC-15-1989
stands for the test results for the CIPP liner sample installed in a 15-in. diameter sewer line in 1989 from
New York City. From this Web page, the user can select a rehabilitation method and download the
testing data into a Microsoft® Excel format for review and analysis. The user can select a specific case
study to review or select to download all of the data for a particular rehabilitation method. The data
downloaded are all of the available raw data.
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Trenchless Technology Center
Louisiana Tech University
&EPA
Batrene
Trenchless rehabilitation methods applied to server mainlines include the use of CIPP. close-fit linings, sliplimng. grout-m-place. spiral-wound linings, panel linings, spray-
on spin-cast linings, and chemical grouting. Further information on various repair, replacement, and rehabilitation technologies for ivastewater collection systems can be
found in the U.S. EPA report titled Stale of Technology for Rehabilitation of Wastewater Collection Systems.
SUMMARY OF WASTEVVATER REHABILITATION TECHNIQUES
CIPP
Close Fit
Sliplining
Grout-in-place Spiral Wound Panel Linings Spray/Spincast Grouting
Thermal Cure
UVCure
Urreinforced
Reinforced
Hybrid
Fo'd-and-Form
Deform SL Reform
Symmetrical/Reduction
Syrr.metrical Cornpress'cr
Syrr-metrica! Expansion
Large Diameter
Small Diameter
Preformed Shapes
Spira; Wound
Circular
Non
Figure 2-2. Rehabilitation Technology Methods Included in the Database
i Trenchless Technology Center
Louisiana Tech University
SEPA
Baiteile
I •••"! >.!..-'.
SELTCT A TECHNOLOGY FOR MORE INFORMATION
^t4rrt MMtwtri Srlrcl Injartnn Wrrl Dnwrliwrt Typr
CIPP » NYC-1S-IOW F| T«iDn
Do«rt»i! Cxcd Rkporl
v or i .s. ti'A itEi
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Figure 2-3. Retrospective Case Studies Included in the Database
The RehabAnalytics Web page provides direct access to plot and view the data within the database
utilizing data mining techniques. Three options are provided to compare different parameters obtained
from the test results performed on the exhumed samples. The RehabAnalytics is currently designed to
plot values for a single technology (e.g., CIPP, deform-reform, fold-and-form, or sliplining). Plots can be
generated for a single sample location and/or across all of the sampling locations for a given technology.
The types of plots that can be generated by the user with RehabAnalytics include the following:
• Mean value plots for a single parameter across all samples;
• Two-dimensional (2-D) scatter plots for the visualization of trends and relationships between two
parameters at a time for a single sample or for multiple samples; and
• Three-dimensional (3-D) plots for further visualization of relationships between three parameters
at a time.
From the Mean Values Plot tab, the user can compare the mean test results for one parameter across all of
the exhumed samples for a given technology. Figure 2-4 shows an example plot of the mean values of
flexural strength for the CIPP samples. Figure 2-5 shows an example 2-D plot indicating an increasing
trend of flexural strength when compared to the tensile strength for CIPP samples. For the 2-D plots,
there is also an optional curve fitting function to assist in analyzing trends in the data. Additional
example 2-D plots are presented in Section 5.3.
= - "
Select Parameters
Select Method
CIFF
Select Parameter
Ts
| Generate Bar Chart |
Mean I 'allies Bar Chart
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Figure 2-4. RehabAnalytics Mean Value Plot for Flexural Strength of CIPP Samples
ALL CITIES CIP
s^> 1 a rifjn -
Sj 18UU
CO
1*1 -irww
Flexura
-^
<
t-
V
*
k
4
P
4 NYC-15-1989
O NYC-12-1988
4 IND-42-1986
O EDM-8-1994
4 EDM-10-1994
O HOU-2 1-1996
O HOU-18-1996
O NASH-8-1994
4 NASH-8-2004
4 NB-12-1979
4 DEN-8-1984
4 DEN-48-1987-DS
4 DEN-48-1987-US
4 COL-8-2005
4 COL-36-1989
1000 2000 3000 4000 5000 6000 7000
Tensile Strength(psi)
Figure 2-5. RehabAnalytics 2-D Plot of CIPP Flexural Strength versus Tensile Strength
The Web page also makes provision for updating of the database and the uploading of new data into the
database, but this function is not accessible to the public. Information provided on the home page invites
agencies that wish to contribute data to contact the database administrator so that the type and quality of
the data available can be assessed before the data are accepted for inclusion in the database. Once the
approval is given, the data contributor can receive a special administrative access to upload the
contributed data and its supporting information.
2.4
Database Content
The structure of the database has been targeted towards making the retrospective evaluation test result
data on rehabilitation technologies available for analysis by the user and industry communities. Table 2-1
shows the key test parameters currently incorporated into the database for CIPP samples and the planned
testing parameters for the additional technologies including deform-reform, fold-and-form, and sliplining.
The full database is comprised of two types of information: site background information (Table 2-2) and
testing results data (Table 2-3). Site background information about the host pipe and its location, liner,
and agency are considered as firm and not likely to be updated. As the sample retrieval and associated
data collection work progressed, it became clear that many municipalities do not have complete historic
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information on the rehabilitation technologies used, specifications at the time of installation, or follow-up
evaluations providing any problems identified. Therefore, the site background information listed in Table
2-2 is provided to the extent available from each participant. The test data in the database as listed in
Table 2-3 are always listed in an updatable format so that new test results can be incorporated by the
administrator as required.
Table 2-1. Retrospective Test Parameters in the Database
Method
ASTMD2122
ASTMD638
ASTM D790
ASTM D792
ASTM D2240
Test
Thickness
Tensile Strength
Tensile Modulus
Flexural Strength
Flexural Modulus
Apparent Specific
Gravity
Durometer (Shore D)
Hardness
Pipe Rehabilitation Method
CIPP
*
*
*
*
*
*
*
F&F PVC
*
*
*
*
*
*
*
D/R
HOPE
*
*
*
*
*
*
*
Sliplining
*
*
*
*
*
*
*
* Currently included
Table 2-2. Site Background Information Listed in the Database
Firm Parameters
Agency Assessment Data
Agency
System Type
System Length (miles)
Technology Used
Technology Length (ft)
Date First Used
Frequency of Installation Issues
Severity of Installation Issues
Description of Installation Issues
Frequency of Long -Term Performance Issues
Severity of Long -Term Performance Issues
Description of Long -Term Performance Issues
Overall Assessment of Long -Term Cost-Benefit Value
Site Sample Data
Rehabilitation Type
Date of Rehabilitation
Approximate Age
Date Collected
Host Pipe Location
Site Sample Data (continued)
Host Pipe Shape
Host Pipe Diameter
Host Pipe Depth
Visual Observations
Sample Photo
CIPP Type
Liner Design Thickness (mm)
Liner Installer
Tube Manufacturer
Tube Material Type
Tube Material Construction
Sealing Layer Type
Sealing Layer Thickness (in.)
Resin Supplier
Resin Type
Resin Trade Name
Primary Catalyst
Secondary Catalyst
Soil Analysis
10
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Host Pipe Material
Table 2-3. Updatable Test Data for Particular Samples
Updatable Parameters
Thickness
Pipe Inside Diameter
Pipe Outside Diameter
Density/Porosity
Tensile Strength
Tensile Modulus
Flexural Strength
Flexural Modulus
Apparent Specific Gravity
Environmental Stress Cracking
Durometer (Shore) Hardness
Pipe Stiffness
Glass Transition Temperature
Short-Term Liner Buckling Strength
Pipe Ovality
Environmental Service Conditions
The main sample test data included are thickness (ASTM D2122), flexural modulus and flexural strength
(ASTM D790), tensile modulus and tensile strength (ASTM D638), apparent specific gravity (ASTM
D792), and hardness (ASTM D2240). Also included in the database are other specific tests that can aid in
the understanding of liner performance and degradation. The procedures for the collection of the main
sample test data are provided in Appendix A, along with the specific test protocols followed for the
collection of the field samples and their subsequent evaluation and testing.
2.5 Data Interpretation
One of the purposes of assembling the database is to allow for the investigation of correlations among the
testing parameters and also in relation to host pipe and service conditions. In order to chart testing results
on a 2-D plot, it is necessary to have a value on the "X" axis paired to a matching value on the "Y" axis.
However, each test as described above may involve a different number of measurements for replicate
specimens from a single sample. For example, the tensile strength testing method (ASTM D638) calls for
at least five specimens to be tested for each sample, while for the apparent specific gravity/density
(ASTM D792) up to 20 specimens were tested for each sample. This results in an unequal number of
measurements for a given sample. Therefore, a dataset with 15 tensile strength values and 20 specific
gravity results would result in 15 "paired" results that could be plotted and five "unpaired" specific
gravity results that could not be plotted or plotted on one of the axes. While this does not affect the
ability to plot the mean values of the data, it does affect the ability to create scatter plots from the raw data
for each sample.
To mitigate the unequal number of measurements, additional tests were run above the prescribed
minimum values in the ASTM methods (e.g., up to 15 replicates of ASTM D638 and D790 were run
versus only five replicates). However, unequal numbers of measurements still exist. A statistical
approach was developed to generate estimated or "synthetic" data for plotting purposes only. In this
approach, the tensile modulus, bending modulus, bending strength, and hardness were assumed to be
functions of density. It was assumed that the relationships between the specimen's density and its tensile
modulus, bending modulus, bending strength, and hardness are proportional. The resulting synthetic data
would have the same linear relationship to density as the observed data. The data synthesized using this
statistical approach are only used for the viewing of trends in the data within the RehabAnalytics plotting
functions. The statistical approach uses an ordinary least squares regression model. The natural
logarithm of each measurement is the independent variable and the natural logarithm of density is the
dependent variable as follows:
11
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\\\(measurementi) = a + /3 In(densityj) + £j
where a is intercept, /?is slope, measurement is any of the measurements with unpaired values (tensile
modulus, bending modulus, bending strength, and hardness) and EJ is the error associated with the linear
model for the ith measurement. The model is fit to the paired observations. The "unpaired" observations
are assumed to be distributed at random. Once the linear model is fit, the (natural logarithm) predicted
values based on the model are calculated for both the paired and unpaired measurements. Next, the
prediction variance associated with each of the measurement predictions is calculated according to:
which is the prediction variance associated with ordinary least squares regression modeling.
Mean squared error (MSB) of the model is:
1 Y"1
MSE = - - / (observed — predicted}2
n — 2 Z—i
where n is the number of paired observations used to fit the linear model. A random number from a
standard normal distribution with the calculated prediction variance is generated to represent noise in the
prediction. The statistical approach uses the Box-Muller transform to generate independent, normally
distributed random numbers. The noise was added to the natural logarithm predicted value and then
transformed back to the original scale.
To provide an illustration of this statistical transformation process, a specific example is described below.
The step-by-step calculation for this example is shown in Table 2-4 and continued in Table 2-5. In this
example, 15 tensile modulus values (Table 2-4, Column 2, Tensile Modulus) and 20 density values (Table
2-4, Column 1, Density) are considered related to the NYC-15-1989 sample. In this example it is
assumed that the five largest tensile modulus values are unpaired; however, in the algorithm for the
database the unpaired values are assumed to be distributed at random. The following steps describe the
statistical procedure:
• The magnitudes of the tensile modulus values are in a range 104 higher when compared to the
density values. Therefore, the 15 available tensile modulus values and the 20 available
density values were represented by their natural logarithms (Table 2-4, Columns 4 and 3).
• Next, the intercept (alpha) and slope (beta) of a plot of the 15 available pairs of tensile
modulus versus density values were calculated using linear regression. A linear equation was
obtained using the calculated intercept and slope values.
• All density values, including the five "unpaired" density values (i.e., those without
corresponding tensile modulus values), were then plugged into the equation and predicted
values of the natural logarithm of the tensile modulus were calculated (Table 2-4, Column 7,
Predicted ln[Tensile Modulus]).
• The errors of the predicted values for the available 15 tensile modulus values were computed
(Table 2-5, Column 1, Error) and the mean squared error (Table 2-5, Column 3, MSE) of the
tensile modulus values was calculated.
• The mean of the natural logarithms of the 15 corresponding available density values was
calculated (Table 2-5, Column 4, Mean[ln{Density}]) and was used along with the MSE to
12
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calculate the variance associated with the prediction of the five "additional" tensile modulus
values (Table 2-5, Column 5, Prediction Variance).
• Finally, the noise of the density values corresponding to the five "additional" tensile modulus
values was calculated using the Box Muller transformation (Table 2-5, Column 6, Noise)
based on which the final value of each "synthetic" tensile modulus value was estimated
(Table 2-5, Column 7, Synthetic Tensile Modulus) and used as synthetic data by
RehabAnalytics to prepare a plot.
Table 2-4. Synthesis of Additional Tensile Modulus Values for Plotting Purposes (Part 1)
^=>
Density,
pcf
78.64
82.1
81.52
80.47
80.82
80.16
80.89
80.81
80.08
79.03
81.6
84.08
83.25
82.3
80.33
83.12
83.79
81.21
82.31
83.85
Tensile
Modulus,
psi
462521
605810
532143
558672
533626
533729
732320
535320
567942
577666
537092
495523
511923
584860
542363
No Value
No Value
No Value
No Value
No Value
In(Density)
4.3649
4.4079
4.4008
4.3879
4.3922
4.3840
4.3931
4.3921
4.3830
4.3698
4.4018
4.4318
4.4218
4.4104
4.3861
4.4203
4.4283
4.3970
4.4105
4.4290
ln(Tensile
Modulus)
13.0444
13.3143
13.1847
13.2333
13.1875
13.1876
13.5040
13.1906
13.2498
13.2668
13.1939
13.1134
13.1459
13.2791
13.2037
Constant in the
Model Equation*
Alpha
Beta
13.58289
-0.08258
Predicted
ln(Tensile Modulus)
13.2224
13.2189
13.2195
13.2205
13.2202
13.2209
13.2201
13.2202
13.2209
13.2220
13.2194
13.2169
13.2177
13.2187
13.2207
13.2179
13.2172
13.2198
13.2187
13.2171
*Model Equation: ln(Tensile Modulus) = alpha + beta*ln(Density); pcf = pound per cubic foot
13
-------
Table 2-5. Synthesis of Additional Tensile Modulus Values for Plotting Purposes (Part 2)
^>
Error
-0.178
0.095
-0.035
0.013
-0.033
-0.033
0.284
-0.030
0.029
0.045
-0.025
-0.104
-0.072
0.060
-0.017
Squared
Error
0.0317
0.0091
0.0012
0.0002
0.0011
0.0011
0.0806
0.0009
0.0008
0.0020
0.0006
0.0107
0.0052
0.0037
0.0003
MSE
0.0115
Mean
(Intensity])
4.3952
Prediction
Variance
0.013835
0.015024
0.012242
0.012829
0.015145
Noise
0.0172
0.2248
0.1649
-0.0822
0.1195
Synthetic
Tensile Modulus
559668.16
688320.43
649966.78
507093.66
619477.04
The "synthetic" values generated by this process are shown in Figure 2-6.
800,000
750,000
700,000
in '
Q.
g 650,000
"g 600,000
5
a> 550,000
"irt
(1 500,000
450,000
400,000
7
Predicted Tensile Modulus Values
» Actual Value
D Predicted Values
Synthesized Values
D 1
•
>
D
*
Ijiilfr ITP
8 79 80
A
D QD
-"?
4-
4
DD
A
f~5 — (gj-
V A
p
*
81 82 S3 84 85
Density, pcf
Figure 2-6. Raw and Synthetically-Generated Tensile Modulus Values
14
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Within Rehab Analytics, the user can then decide whether or not to utilize this statistical approach by
selecting "0," "50," "100," or "500" for the number of synthetic values to be generated (see Figure 2-7).
For each set of synthetic values generated, the positions of the unpaired values within the distribution of
the data are randomly selected. The "0" mentioned in the dropdown box (see Figure 2-7) indicates that
no synthetic values are generated and only "paired" values are plotted. A comparison of "0" synthetic
value and "100" synthetic values for HOU-21-1996 is shown in Figure 2-8. Both plots indicate the
increasing trend of flexural strength when compared to the tensile strength. It is expected that this
synthetic data addition process yields more understandable and consistent visualization of the data in the
database, but the user also has the option to download the raw data and use this to create their own plots
from the database.
Ta ctnltlcsi Technology Center
Louisiana Tech University
Select Method
H
Srfert L«itfon
ALL CITIES
&d
-------
2.6 Data Mining and Future Applications
The data from the retrospective study were then used in generating plots of interest for further review and
analysis. The potential of the current database to identify relationships among the test parameters is
explored in Section 5.3 of this report. Recommendations for future work in expanding the database are
provided in Section 6.
16
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REHABILITATION METHODS AND THE RETROSPECTIVE EVALUATION PROCESS
This section provides a brief introduction to the common methods used for the trenchless rehabilitation of
sewer and water systems in North America followed by a description of the approach used to evaluate the
performance of selected rehabilitation technologies that had been in service for a significant portion of
their anticipated service life. The discussion of both the methods and their testing is divided into "CIPP
rehabilitation" and "other rehabilitation technologies" because of the dominant position of CIPP
technologies for rehabilitation of sewer systems in the U.S.
3.1
Cured-in-Place Pipe Rehabilitation
This section provides background on the CIPP lining process and describes the protocols used to retrieve
and test the retrospective CIPP samples. A detailed description of CIPP lining technology, its variants,
design issues and test parameters can be found in the pilot study report (EPA, 2012).
The main focus of the initial retrospective evaluation in both the pilot study and this ongoing work was
chosen to be CIPP liners used in gravity sewer systems. This choice was made on the basis of the
extensive current use of this technology in the U.S. market. Apart from sliplining, CIPP was the earliest
trenchless relining technology used in the U.S. and has liners that have been in service for up to 38 years
in the U.S. and up to 43 years in the UK.
CIPP lining involves the impregnation of a liner fabric with a resin either in a factory setting or on site.
The saturated fabric contained within one or more sealing layers is then introduced into the host pipe that
is to be rehabilitated. Once the liner is in place, it is cured using either heat or ultraviolet (UV) light,
depending on the formulation of the resin used. The resulting cured liner provides a close-fit, high-
strength lining to the host pipe and is typically designed to extend the life of the host pipe by a minimum
of 50 years. Figure 3-1 highlights the main variants in CIPP technologies available today based on tube
construction, method of installation, curing method, and type of resin.
^
H
Inversion
Pull-In
and Inflate
Ambtont
-L -
T
UlmvttXM
Light
1
1
1
4
4
Polyester
Vinyl
E*" 1
Epoxy
Figure 3-1. Summary of Common CIPP Technologies
17
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The early CIPP product was a needled felt tube, impregnated with polyester resin that was typically
inverted into a sewer through a manhole and cured using hot water. This product is still used for gravity
sewers. The first known municipal use of a CIPP lining occurred in 1971 in the relining of a 230-ft
(70 m) length of the Marsh Lane Sewer in Hackney, East London. This 100-year old brick egg-shaped
sewer had dimensions of 3.85 ft * 2 ft (1,175 mm x 610 mm). It should be noted that this first installation
was actually a pull-in-and-inflate liner. Inversion was not possible until coated felt was used in 1973
(EPA, 2012).
3.1.1 Pipe Rehabilitation Process Using CIPP. A CIPP project involves a variety of
investigative, planning and execution phases. Once a liner has been identified as needing rehabilitation or
replacement, the characteristics of the liner and the problems experienced will determine if the CIPP
process is a suitable candidate. CIPP is generally available in diameters of 4 to 120 in., depending
(especially in the larger diameters) on the supplier's and contractor's capabilities and experience.
Guidance on this type of decision can be found in the literature on rehabilitation technologies and from
manufacturers and suppliers. Software to support the method selection process also has been developed
and a review of such software development can be found in Matthews et al. (2011 and 2012).
Prior to the relining work, the existing host pipe will be carefully examined (typically using a CCTV
camera inspection) and any necessary additional measurements (such as pipe diameter) collected. Data
on pipe depth, soil type and groundwater conditions will also be gathered.
Based on these data, the following major design parameters would be determined for the use of CIPP in
gravity flow sewers:
• Accurate measurements of the internal diameter of the host pipe and any variations in
diameter along individual sections of pipe to be relined.
• Any ovality in cross-section dimensions for the host pipe (more than 10% ovality is typically
not considered suitable for relining with CIPP because of greatly increased thickness
requirements for the liner).
• Whether the host pipe is considered structurally sound (i.e., the lining is not required to
support the surrounding soil loading). If the pipe is not considered structurally sound, then
additional data regarding the potential soil loading are required including the effect of any
traffic loadings on the pipe/liner system.
• The depth of the pipe below the groundwater level (the maximum depth is often used when
the groundwater depth varies). This water pressure acts on the outside of the liner through
the defects present in the host pipe. The liner thickness is calculated to provide an adequate
safety factor against local buckling of the liner under the external water pressure.
• The presence of particular environmental parameters that may affect the liner design and its
longevity. Such factors may include the aggressiveness of the groundwater or waste stream
within the pipe (e.g. pH or presence of hydrocarbons), the presence of high or low
temperatures that may affect curing and/or the apparent creep modulus over the liner lifetime,
abrasive internal flows, etc.
The key ASTM standards pertaining to different types of CIPP liner installation are shown in Table 3-1.
The structural requirements of the liner are designed for all of the standards using the procedures
specified in ASTM F1216. This is based primarily on a formula for the buckling of thin liners restrained
within a host pipe. Since a CIPP liner is a thermoset plastic material, it exhibits creep displacements over
time under constant load and hence its resistance to buckling over long loading periods is much less than
18
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its short-term buckling resistance. This is accounted for in the F-1216 design approach by using an
estimate of the effective modulus of deformation of the liner over the planned design life of the
rehabilitation. This effective modulus value typically is established by using extended (often 10,000
hour) creep and/or buckling tests for the liner/liner material. The measured values are then extrapolated
to the typical 50-year design life values. Much research has been carried out and many papers written on
the analysis of long-term buckling in such liners and are referenced in the pilot study report (EPA, 2012).
Table 3-1. Key ASTM Standards Covering CIPP Installations
ASTMF1216
ASTM F 1743
ASTMF2019
ASTM F2599
Standard Practice for Rehabilitation of Existing Pipelines and
Conduits by the Inversion and Curing of a Resin-Impregnated
Tube
Standard Practice for Rehabilitation of Existing Pipelines and
Conduits by Pulled-in-Place Installation of Cured-in-Place
Thermosetting Resin Pipe (CIPP)
Standard Practice for Rehabilitation of Existing Pipelines and
Conduits by the Pulled in Place Installation of Glass Reinforced
Plastic Cured-in-Place Thermosetting Resin Pipe (CIPP)
Standard Practice for The Sectional Repair of Damaged Pipe By
Means of An Inverted Cured-in-Place Liner
The required thickness of the liner depends on the effective long-term modulus of the liner, its Poisson's
ratio, its mean diameter, its ovality and the chosen safety factor, in addition to the external loading
conditions provided by the groundwater pressure and/or external soil/traffic loadings. An important
factor in the ASTM buckling equation is a correction factor (K) for the degree of buckling restraint
provided by the close fit of the liner within the host pipe. However, in typical designs only a single fixed
value (K = 7.0) is used for this parameter. Where special environmental conditions such as aggressiveness
of groundwater or internal flows and/or temperatures outside the normal range are encountered, the resins
used and the design thickness may be adjusted to account for these differences.
In most cases, the application of the ASTM F1216 equations results in a conservative design for the
required thickness of the liner (Zhao et al., 2005). Conservatism can occur for a variety of reasons, e.g.,
because the groundwater loading used for design is seldom at the assumed value, because only a limited
section of the pipe has the ovality assumed in the design, because the contractor chooses to exceed the
minimum required value of liner modulus to make sure of product acceptance, and/or because the
buckling restraint factor is conservative for the application considered. Such conservatism may provide a
cushion against unacceptable performance in failure modes not considered explicitly in the design
process, e.g. local imperfections in the shape of the host pipe, and accommodate liner flaws that are not
identified by the quality assurance (QA) or QC procedures, e.g. locally weak or porous areas of the liner.
Once the liner materials, liner cross-section, curing method and installation procedure have been decided,
the project execution can occur. Most CIPP liners are impregnated with resin ("wet out") in a factory
setting. A vacuum impregnation process is typically used to allow the resin to flow more easily into the
liner fabric and to more fully saturate it. Prior to 2001, this vacuum impregnation process was covered by
a patent and, hence, other CIPP lining companies often used modified procedures to work around the
patent. After wet out and during transport to the site, thermally-cured liners are kept in refrigerated
storage or in a chilled condition to avoid premature curing of the liner.
19
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Small diameter liners (e.g., for sewer laterals) and very large liners may be wet out at the site. For small
liners, this may be for convenience and is facilitated by the relative ease of handling a small diameter
liner during wetting out. For large diameter liners, the large liner thickness coupled with the large host
pipe diameter means that the lay-flat liner becomes too heavy or too wide to transport when wet out.
However, on-site wet out puts an extra burden on QC for the impregnation process.
When the impregnated liner is ready, it is introduced into the host pipe to be relined. This can be done by
inversion of the liner along the host pipe using water or air pressure or by pulling the liner into place and
then inflating it to a close fit using water or air (see Figure 3-2).
Figure 3-2. CIPP Installation Options: Liner Pull-in (left) and Liner Inversion (right)
(Courtesy Insituform Technologies, Inc.)
Once the uncured liner is in place and held tightly against the host pipe, the liner is cured using hot water,
steam or UV light, causing the liner resin to become a cross-linked and solid liner material. The curing
procedures (time and temperature curves for thermal curing and UV light intensity and advance rate for
UV curing) are important in making sure that the full thickness of the liner becomes properly cured and
that thermal or other stresses are not introduced into the liner in a partially cured state.
Following the full curing of the liner and removal of any accessory installation materials, the restoration
of lateral connections can be carried out. These are typically simply restored by cutting openings at the
lateral connection. A dimpling of the liner can aid in the identification of the position of the connection,
but such dimpling is less identifiable in liners with higher strength fabrics. If the CIPP liner has a
significant annular space and if the connection is not grouted or sealed to the sewer lateral, then this
connection can be a source of continued infiltration into the mainline sewer.
3.2
Steps for the Retrospective Study of CIPP Liners
The retrospective testing for CIPP liners in the current study generally followed the progression of
activities in the pilot study as outlined below:
• The most effective evaluation tests from the pilot study were chosen to evaluate the current
condition of a CIPP liner and provide information on its potential longevity.
20
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• Approval of the liner test protocol by EPA was received through review and approval of the
STREAMS TO 1 Quality Assurance Project Plan (QAPP) titled Retrospective Evaluation of
Cured-in-Place Pipe Liners (Battelle, 2012a).
• The proposed liner evaluation protocol and its expected benefits were discussed with
interested municipalities.
• Municipalities identified previously installed CIPP liners with as many years of service as
possible.
• Detailed discussions were held with the interested municipalities regarding the division of
responsibilities and costs for the field retrieval of samples.
• Once the sites were agreed upon, the detailed planning of the sample retrieval was
undertaken, the field work carried out, and the test sections/samples shipped to the TTC for
testing.
• The test data for each site were collected and evaluated. Comparisons with the pilot study
data and the qualitative evaluations of CIPP lining performance were made.
• The data were included in the newly formulated database structure.
Under the current work, samples from 13 CIPP liners from seven cities were obtained and tested. One
additional sample was defective (NY sample 1). Its retrieval and condition is described in Appendix B
but the sample was not subjected to detailed testing and is not included in the overall sample count. This
was in addition to the samples from five CIPP liners from two cities that were obtained in the pilot study
as discussed in Section 1.3. The summary results of the pilot study testing are compared with the test
results obtained in this research phase in Section 5.
3.3 Testing and Measurement Protocols for CIPP Liners
The testing and measurement protocols used are described in Appendix A. The parameters to be
measured included visual inspection, environmental service conditions, annular gap, liner thickness,
ovality, specific gravity, tensile strength/modulus, flexural strength/modulus, surface hardness, glass
transition temperature, and porosity. ASTM testing standards were followed according to the parameter
being measured. Where ASTM standards were not available (e.g. visual inspection, annular gap, liner
thickness, ovality and environmental service conditions), the procedures used, numbers of measurements,
specimen photos, etc. are provided either in Appendix A or B. The following principal ASTM test
standards were used in the laboratory testing of the current retrospective samples (a full list of ASTM
Standards mentioned in the report is provided in Appendix E): specific gravity (ASTM D792), tensile
properties (ASTM D638), flexural properties (ASTM D790), hardness (ASTM D2240) and glass
transition temperature (ASTM D1356). The testing parameters also depended on the size of the sample
retrieved. For example, ovality and buckling tests were only applicable to whole pipe samples collected
from small diameter pipes. In some cases, due to the sample retrieval process, the site conditions or the
host pipe/liner condition, it was not possible to collect all of the data for all of the samples. The specific
information collected for each sample is provided with the discussion for each test location in Appendix
B. This appendix describes the data collection, analyses, and project documentation in accordance with
EPA NRMRL's QAPP Requirements for Applied Research Projects (EPA, 2008) and the project-specific
QAPPs (Battelle, 2012a; 2012b; and 2013).
3.4 Overview of Other Rehabilitation Technologies
3.4.1 Wastewater. As shown in Figure 3-3, a variety of trenchless rehabilitation methods have
21
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been or can be applied to sewer mainlines including the use of CIPP linings, close-fit linings, grout-in-
place, spiral-wound linings, panel linings, spray-on/spin-cast linings, and chemical grouting. Pipe repair
(e.g., repair sleeves or short CIPP liners) and pipe replacement methods (e.g., sliplining and pipe bursting)
can also be carried out using trenchless technology approaches. These all represent an alternative to the
traditional dig and replace method of sewer renewal. Further information on these various repair,
replacement, and rehabilitation technologies can be found in companion EPA reports (EPA, 2009, 2010).
The 2010 report (EPA, 2010) also contains datasheets for most of the products/technologies available in
the U.S. Both reports are available for free download from the EPA Aging Water Systems website
(URLs are provided in the reference section at the end of this report). The test results for the retrospective
pilot study of fold-and-form (polyvinyl chloride [PVC]) lining, deform-reform (high density polyethylene
[HDPE]) lining, and sliplining are also included in this report.
Wastewater collection systems also may include pressure sewers (force mains) to convey sewage when
gravity flow is not the preferred option. Rehabilitation technologies for pressure sewers have more in
common with the rehabilitation technologies used in water distribution systems than those used only for
non-pressure sewerage applications. While they are a potential future target for retrospective evaluation,
they are not included in the current phase of the research.
CIPP
Thermal
Cure
UV
Cure
i Unreinforced
- Reinforced
Hybrid
Close Fit
Rehabilitation
.
Fold-and-
Form
Symmetrical
Reduction
Symmetrical
Compression
Symmetrical
Expansion
Sliplining
Large
Diameter
Small
Diameter
Grout-in-
Place
i
^ Preformed
Shapes
Spiral
Wound
Spiral
Wound
- Circular
Non-
Circular
Panel
Linings
Full
Ring
Partial
Ring
Spray/
Spincast
-t Cementitious
Epoxy
i Polvurethane
PC'lyurea
Grouting
J Test and
1 Seal
Flood
Grouting
Figure 3-3. Summary of Trenchless Sewer Rehabilitation Technologies
3.4.2 Water. Trenchless rehabilitation methods for water mains are shown in Figure 3-4 and
include the use of spray-on-lining, sliplining, CIPP, inserted hose lining, and close-fit lining systems
(EPA, 2013). Trenchless rehabilitation for water mains typically relies upon the existing pipe becoming
part of the renewal work. If the rehabilitation is to provide only corrosion protection, or the existing pipe
is only partially deteriorated, then the remaining structural strength of the existing pipe can be
incorporated into the fabric of the completed system. For fully deteriorated water mains, the existing pipe
acts merely as a right-of-way or a platform for the installation of a fully structural liner that must be
designed to carry all of the imposed internal and external loadings. Sliplining, which can be considered a
replacement method because a completely new line is inserted inside the old line, also is included for
22
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further consideration in a future retrospective study of water main renewal. Other repair and replacement
methods (e.g., pipe bursting) are available, but are not considered as candidates for a future retrospective
study at this time.
Trenchless water main rehabilitation using spray or spincast linings was the earliest form of water main
rehabilitation, but the principal use of these linings has been to provide corrosion protection or taste
control within the water main. Structural spray or spincast linings that have the capability to resist
internal pressures, while spanning defects within the host pipe, are a later development. Fully structural
sprayed linings have only been tried in the U.S. in the last few years.
Sliplining has been used for renewing pressure pipes for many years (particularly in the gas industry), but
since it often requires increased system pressures to compensate for the loss of pipe diameter, it has some
limitations on its use.
Rehabilitation
1 1
1
Spray-On
Lining
Sliplining
1
CIPP Inserted
Hose Lining
1
Close-Fit
Lining
Figure 3-4. Rehabilitation Approaches for Water Mains (EPA, 2013)
Close-fit linings, created by inserting a reduced diameter lining pipe within the host pipe and then
expanding it or re-rounding it to fit tightly, emerged in the U.S. in the 1990s.
Hose liners are relatively thin and flexible liners inserted within a pressure pipe that are only designed to
withstand the internal pressure loadings in service. The host pipe must continue to resist all the external
loads.
CIPP liners for water main rehabilitation have many similarities to the CIPP systems used in gravity
sewers, but the application to smaller diameters, the internal pressure resistance requirements, and the
requirements of being applied in a drinking water system means that considerable adaptation is required.
CIPP for water mains now has a 15+ year history for trenchless rehabilitation in North America.
The interest in trenchless rehabilitation of water systems has been increasing in the U.S. in recent years.
Now that structural linings, as well as corrosion protection linings, have reasonable lengths of time in
service, it is considered very worthwhile to extend the retrospective evaluation to water system
rehabilitation technologies.
3.5
Other Technologies Considered for Evaluation in the Current Phase
As mentioned earlier in this section, the current phase of the research expanded on the number of sites for
CIPP evaluations, as well as started to gather information on the long-term performance of other
23
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rehabilitation technologies. To identify the most appropriate technologies for evaluation along with the
interest of municipalities in providing samples, a review of issues, difficulties, and opportunities for the
principal forms of rehabilitation technologies other than CIPP was conducted. A brief summary of the
evaluations in terms of suitability for the current phase of the work is given below.
• Newer CIPP systems including UV cure and reinforced liner systems are gaining in
application, but have less time in service compared to standard CIPP installations. With the
main focus of the research to date being on CIPP, it was desired to address other
rehabilitation technologies before adding other CIPP variants.
• Sliplining has a long history of use and has been considered in the two categories of large
diameter sliplining and small diameter sliplining. The large diameter applications would
allow the removal of samples from the pipe wall by person entry. However, the techniques
for patching and the arrangements for access/bypass can present significant barriers. Smaller
diameter sliplining often involves continuous lengths of pipe and hence functions more as a
replacement pipe than a rehabilitated pipe. Sliplining samples were recovered for testing in
this phase of the research as one of the oldest replacement techniques used by the City of
Houston, which participated in the study.
• Close-fit linings for sewer application have typically comprised fold-and-form (PVC) and
deform-reform (HDPE). Although neither is marketed in the U.S. at present, there is a
reasonable service life for samples in some municipalities. Municipalities were available that
could provide samples and it was considered worthwhile to study these systems as a guide to
municipalities that have such systems and as a guide for evaluating issues should future
similar systems come to the market. Samples for both fold-and-form and deform-reform
were recovered in this phase of the research.
• Grout-in-place linings and panel linings are typically large diameter installations and
access/bypass issues are similar to those for large diameter sliplining. There are, however,
installations with reasonable lengths of service around the country.
• Spiral wound linings have been used in small diameter sewers and also as grout-in-place
linings in larger diameters. However, they have not been used in many cities and hence it is
necessary to find a municipality with older spiral wound installations that are willing to
participate in the study. For the larger diameter applications, access/bypass expenses remain
issues.
• Spray and spincast lining technologies are mainly applied to manholes within the sewer
sector. Manhole rehabilitation technology evaluation is considered an important topic, but is
not part of the current research scope.
• Rehabilitation (infiltration and inflow [I/I] sealing) by grouting is an important technique
with quite different cost and application criteria when compared with relining strategies. It is
considered very worthwhile to collect better information on the longevity and performance
issues for grouting applications, but the sampling and evaluation protocols present significant
difficulties due to the nature of the process. The precise locations of grouting within a main
and the contractor procedures/pressures/materials, etc. used are often unknown for a
particular section to be evaluated, complicating any evaluation. It was decided not to include
grouting evaluation in this phase of the research.
• Water main rehabilitation technologies are a good target for future evaluations, but were
deferred until a later phase of the research because, with the exception of corrosion protection
linings, the application of the technologies is more recent than for sewer systems.
24
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3.6
Force main (pressure sewer) rehabilitation technologies also should be a future target, but the
same issues apply as for water systems and sewer force mains are not as prevalent as gravity
sewer mains or water distribution mains.
Testing and Measurement Protocols for Fold-and-Form (PVC), Deform-Reform
(HOPE), and Sliplining
The retrospective evaluation protocol outlined in the STREAMS TO 1 QAPP was extended to include the
additional rehabilitation technologies to be studied in this phase of the research (Battelle, 2013).
Additional testing and measurement protocols suitable for each technology under consideration were
added to the amended QAPP including both field and laboratory measurements and the changes/additions
are presented in this section. Table 3-2 lists the key ASTM standards relating to the installation of fold-
and-form liners, deform-reform liners and slipliners. The testing and measurement protocols for these
rehabilitation technologies are listed in Appendix A.
Table 3-2. Key ASTM Standards Covering Fold-and-Form (PVC), Deform-Reform
(HOPE), and Sliplining
Standard
ASTM D 1784
ASTM D3350
ASTM F585
ASTM F1504
ASTMF1533
ASTM F 1867
ASTM F 1871
Description
Standard Specification for Rigid Poly(Vinyl Chloride) (PVC) Compounds and
Chlorinated Poly(Vinyl Chloride) (CPVC) Compounds
Standard Specification for Polyethylene Plastics Pipe and Fittings Materials
Standard Guide for Insertion of Flexible Polyethylene Pipe Into Existing
Sewers
Standard Specification for Folded Poly(Vinyl Chloride) (PVC) Pipe for
Existing Sewer and Conduit Rehabilitation
Standard Specification for Deformed Polyethylene (PE) Liner
Standard Practice for Installation of Folded/Formed Poly (Vinyl Chloride)
(PVC) Pipe Type A for Existing Sewer and Conduit Rehabilitation
Standard Specification for Folded/Formed Poly (Vinyl Chloride) Pipe Type A
for Existing Sewer and Conduit Rehabilitation (Withdrawn 201 1)
25
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RELATED STUDIES OF CIPP PERFORMANCE
In this section, a number of recent and ongoing studies of CIPP performance, QA, and longevity are
briefly summarized together with a summary of the findings from the international scan carried out during
the pilot study (EPA, 2012). The findings from these studies are then included as appropriate in the
discussion of CIPP performance provided in Section 5 and in the overall conclusions from the report.
General findings are presented from the literature worldwide including U.S. studies (Section 4.1),
Canadian studies (Section 4.2), international scan (Section 4.3), European studies (Section 4.4), and Asian
and Australian studies (Section 4.5).
4.1
U.S. Studies
Summaries of the prior pilot study phase of this project have appeared in several journal papers and
conference proceedings (Alam et al., 2011; Allouche et al., 2011; Allouche et al., 2014), as well as in the
full report available on the EPA Web site (EPA, 2012). The overall findings were summarized in Section
1.3 and are not repeated here.
A paper by Harada et al. (2011) provides an excellent summary of the issues affecting the in-place CIPP
liner thickness, as well as appropriate techniques to sample the thickness to ensure that the minimum
design thickness is being met. The paper also draws together test data from the Institute fur Unterirdische
Infrastruktur GmbH (IKT) in Germany showing the proportion of liners tested that met the thickness
specified over the years from 2003 to 2008 (see Table 4-1). The IKT reports and their references are
provided in Section 4.4.
Table 4-1. IKT Test Results for Wall Thickness
Year
2003/2004
2004/2005
2006
2007
2008
2010
2011
% Passing
79.2-100.0
86.4
82.7
87.8
92.1
89.1
96.2
Source: Harada etal., 2011; IKT, 2011
On a related topic, Shah et al. (2008) present a benchmarking study carried out by the City of Los
Angeles to compare the design parameters used to determine the specified CIPP liner thickness.
A paper by Porzio (2014) examines quality issues and the water tightness of CIPP especially regarding
deterioration or blistering of the coating and subsequent leakage through the liner.
Muenchmeyer (2007) presents an overview of CIPP quality issues and how the growth and fragmentation
of the industry creates QA issues. He outlines the generally more stringent QA/QC requirements in
26
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Europe. Lee and Ferry (2007) discuss the issue of estimating the design life for CIPP rehabilitation in
relation to the testing of the creep properties of the liner. The importance of estimating the effective
modulus reduction of a liner subjected to continuous loading over 50 years compared to short-term
flexural tests is discussed and possible errors in interpreting laboratory creep tests identified. The paper
provides some proposed specifications to balance the cost of testing versus the assurance of long-term
performance, but does not provide any field evaluation of liner performance over time.
A paper by Herzog et al. (2007) described a study conducted to compare the mechanical properties of
field samples from CIPP liners with samples prepared in the laboratory. The conclusions from the study
that involved 10 field generated samples and three laboratory prepared samples were as follows:
• The processes used in the field to create the samples are fairly consistent job to job.
• The field application of the CIPP process generates a high degree of cure in the composites.
• The variation found in the degree of cure seen in the samples does not cause any of the
differences seen in the physical properties of the composite.
• The tensile properties are not influenced by the percent of resin in the resin/felt composites.
• The tensile properties are not influenced by the difference in the surface quality between the
field and laboratory samples.
• The flexural properties are not influenced by the percent of resin in the resin/felt composites.
• The difference in the surface quality between the field and laboratory samples only has a
minor effect on the flexural modulus.
• The difference in the surface quality between the field and laboratory samples has a major
effect on the flexural strength.
A paper by Shelton (2012a, 2012b) presents data obtained from CIPP inspections over a 6-year period
following the introduction of both post-rehabilitation and warranty inspection requirements. The
inspections encompassed approximately 50 miles of mainline liners, varying in diameter from 8 in. to 42
in. and approximately 1,200 lateral liners plus review of approximately 5 miles of liners installed under
other programs of an earlier vintage (5 to 15 years). The CIPP installations involved cover many different
contractors/manufacturers in the U.S. and all of the major variants of CIPP relining materials and
processes. The findings of the inspections revealed a frequent occurrence of several types of defects
including pinhole leaks, seam defects and delamination or fraying of the sealing layer. Some defects were
discernible in the post-rehabilitation inspection, but more became evident in the warranty inspection. The
warranty inspection was initially conducted at 12 to 18 months after rehabilitation, but because of the
evidence that defects worsened with time and that more defects became visible, the warranty inspection
period was extended to 2 to 3 years following rehabilitation. The paper also provides hypotheses for the
causes of the defects and specification changes used to help eliminate the defects seen for the various
types of CIPP liners according to the site conditions for installation.
Further information on CIPP experience in the U.S. was obtained through discussions with U.S.
municipalities participating in the retrospective study (see Appendix D of this report). The lengths
installed by individual municipalities ranged from 39,400 ft to approximately 1.5 million ft. All had used
thermal cure CIPP and one municipality also reported using UV cure CIPP. The first thermal cure CIPP
installations among these municipalities were in the 1970s in New York.
For thermal cure CIPP, the utilities indicated the severity of the installation issues for CIPP to be "almost
none" to "minor" and primarily occurring at an estimated frequency below 4% (four out of five
27
-------
participating utilities). Four of the five utilities reported the severity of long-term performance issues for
CIPP to be "almost none" to "minor" with one listing this as "moderate." The occurrence of such long-
term performance issues was assessed at an estimated frequency below 4% (five out of five participating
utilities). The overall assessment of long-term cost-benefit value for thermal cure CIPP was deemed to be
"high" for all of the participating municipalities.
The types of installation issues indicated included the following:
• Wrinkles/folds in liner; poorly sized liner
• Missed taps or over/under cutting
• Failure of resin to cure /inadequate curing resources
• Collapse of liner
• Rough cuts on taps
• Inconsistent resin impregnation
• Care and experienced installers a requirement for success
• Premature resin curing
• Resin slugs in laterals
• Inability to span voids
• Inadequately prepared/televised pipe
• Styrene odor complaints for larger diameter installations.
The key long-term performance issues identified were as follows:
• Delamination of sealing layer
• Excessive wrinkles causing constriction in main
• Wrinkles impact cleaning and CCTV
• Infiltration at lateral openings
• Roots still enter main from non-rehabilitated laterals
• Large piece of CIPP liner found on wastewater treatment plant screen.
Other key issues related to CIPP rehabilitation were as follows:
• Maintenance practices need to be modified/controlled to avoid damage
• Used in larger diameters where loss of cross-section is less important
• Pipe bursting preferred when diameter less than 15 in. and depth less than 15 ft; CIPP
preferred for diameters between 24 in. and 108 in.
• Tried and true method; continuing to use CIPP; product holds up well
• Great product, but still have some water entering the system through annular space
28
-------
4.2
• Good results for both thermal and UV-cure CIPP; no long-term failures.
Canadian Studies
Papers by Macey and Zurek (2012) and Macey et al. (2013) report on the QA program for CIPP lining
undertaken by the City of Winnipeg, Manitoba, Canada, which has a sewer system that serves
approximately 700,000 people. The city and its consultant also provided physical samples for testing
under the program described in this report. These results are provided in Appendix B.
Winnipeg commenced sewer rehabilitation with CIPP in its first trial installations in 1978; CIPP has been
used for approximately 75% of the annual rehabilitation program from 1998 to date. The papers present
the results of 34 years of QA testing in terms of ASTM D790 flexural modulus of elasticity and flexural
strength testing. Most test results in the city's database are from the completion of construction, but
retrospective testing on retrieved samples recently has been carried out. The data compiled represent one
of the most comprehensive databases of CIPP flexural modulus and strength values in North America.
It was reported in the Macey and Zurek (2012) paper that the database included over 1,500 separate D790
tests for both flexural strength and flexural modulus. Given that each test is comprised of at least five
individual tests, the results include the testing of over 7,500 samples. The paper provides graphs of
flexural strength and flexural modulus data separated by the type of sampling used (plate sample,
confined pipe sample, or tail end sample) and flexural modulus data grouped by contract. At the time of
the Macey and Zurek (2012) paper, physical testing was under way for two CIPP liners installed in 1978.
The Macey et al. (2013) paper provides more background on the early installations of CIPP in Winnipeg
(in 1978 and 1984) and the evolution of the program into the principal means of renewing sewers in
Winnipeg. The test data mentioned in the 2012 paper and presented at the 2012 conference are
documented in the 2013 paper. The liners tested were specified to have a minimum flexural modulus of
240,000 psi (1654 MPa), flexural strength of 8,200 psi (-56.5 MPa) and a tensile strength of 4,130 psi
(28.5 MPa). They had a nominal thickness of 6 mm, which was shown in the paper to be a smaller
thickness than if the liners were designed following current practice. The 2012 test results after 34 years
in service are shown in Table 4-2. A third liner installed in 1984 was reported to be scheduled for
recovery and testing at the time of writing of the 2013 paper. The full set of flexural data also was
provided for inclusion in the database and the average value results are included in Table 5-1 and 5-8.
Table 4-2. City of Winnipeg Test Results for 34-Year Old CIPP Liners
Parameter
Flexural
Modulus
Flexural
Strength
Kingsway Liner
(454 mm [18 in.] host
pipe at 3.76 m [12.3 ft]
depth)
Low End
MPa (psi)
1,881
(272,816)
38
(5,511)
High End
MPa (psi)
2,586
(375,068)
51
(7,297)
Richard Liner
(762 mm [30 in.] host
pipe at 5.40 m [17.7 ft]
depth)
Low End
MPa (psi)
3,092
(448,457)
50
(7,252)
High End
MPa (psi)
3,144
(455,999)
58
(8,412)
MPa = megapascal
29
-------
While there was a wide variation of the results between the sites, the paper provided the following
observations:
• All CIPP samples exhibited good, non-brittle material characteristics
• All of the flexural modulus testing was above the specified initial properties
• All of the flexural strength tests, save one, exhibited values very near their initial specified
values
• The only low flexural strength value was associated with a liner with visible installation
related issues.
The paper also commented on the excellent visual appearance of the CIPP lined sewers in the city based
on the city's ongoing sewer condition assessment program.
A paper by Alzraiee et al. (2013) describes a physical testing program that was used to verify the
structural integrity of CIPP liners in the Province of Quebec, Canada, which had been installed in 2001.
Tests were conducted on sewer pipe samples with nominal host pipe diameters of 450 mm (18 in.) and
300 mm (12 in.) retrieved from two locations in Quebec, after 10 to 11 years in service. The host pipe
depths were reported as approximately 1.5 m (5 ft) (only 1 depth provided in the paper) and 3 m (10 ft)
long sections of host pipe and liner were retrieved at each site and each cut into three approximately 1 m
(3.3 ft) long samples providing six samples in total. The samples were retrieved and tested in 2011.
Flexural (ASTM D790) and tensile (ASTM D638) testing were conducted, along with measurements of
thickness and annular gap. Testing of four of the samples as a pipe-liner system was mentioned in the
paper, but no results were provided. Results were compared with physical and structural design
parameters used at the liner design stage and with test results published for another (unidentified) city for
liners with an age of 30, 26 and 20 years of service.
The liner was reported to be designed for 2,758 MPa (400,000 psi) flexural modulus and 27.6 MPa
flexural strength (4,000 psi). The flexural modulus design value exceeds the ASTM F1216 minimum
value (250,000 psi), but the flexural strength design value reported is lower than the ASTM F1216
minimum value (4,500 psi). The C12 liner samples were reported to have the larger sample thickness
although the C12 diameter was reported to be smaller than the C14 samples. Average annular gaps
between the liner and the host pipe were generally small for four of the six samples (around 0.5 to 0.7
mm). One sample had essentially zero annular gap but the final sample had a large annular gap on one
side of the sample (up to 20 mm) with the other side of the liner being tight to the host pipe.
In Table 4-3 abstracted from the 2013 paper, the main test results are summarized. It is assumed that the
tensile moduli were reported incorrectly and should have been perhaps 1,000 times greater to bring them
into the same range as expected tensile modulus results but they have not been adjusted in the table shown
here.
Table 4-3. Retrospective Test Data from Quebec
Sampl
e Sets
Design
Min.
Thicknes
s (mm)
Av.
Sample
Thicknes
s (mm)
Av.
Tensile
Breakin
g Stress
MPa
(psi)
Av.
Tensile
Elongatio
n at break
Av.
Tensile
Modulu
sMPa
(psi)
Av.
Flexural
Modulus
MPa
(psi)
Av.
Flexural
Strengt
hMPa
(psi)
30
-------
(C12)
(C14)
(C12/
C14)
7
5
Combined
set
8.29
6.94
7.88
19.85
(2879)
24.38
(3536)
-
3.50
10.33
-
1.75
(254)
5.16
(748)
-
-
-
3,460
(501,830
)
-
-
45.85
(6,650)
Source: Alzraiee et al. (2013)
A follow-up paper (Alzraiee et al., 2014) presents the results of laboratory controlled deflection tests
conducted on the liner samples within their vitrified clay host pipe. The tests demonstrated the influence
of the CIPP liner on the structural response of the liner host pipe system.
Papers by Araujo et al. (2009, 2010, Araujo and Yao, 2014) explore the potential variability in CIPP test
results according to the choices made in sample selection and preparation allowed within the relevant
ASTM standards. Variations of several tens of percent in the measured parameters are possible
depending on the way that the sample is prepared from the curved liner, whether the surface layers are
removed or not, the location within the thickness of the samples and the orientation of the specimen
(longitudinal or circumferential). The 2010/2011 paper documented the extent of variation seen and the
2014 paper examined the underlying root causes. These were shown to relate both to the conditions of
preparation of the "representative" sample in the field and to how the nature of the sample affects the
testing. In the 2014 paper, important testing issues were shown to be: whether the test sample is
machined to a parallel sided specimen or tested at full liner thickness, where within a liner thickness a
parallel-sided specimen is cut, variation in thickness for full thickness specimens, stress concentrations
arising from the contact of the curved liner surface with the support and loading mechanism of the test
equipment for full liner thickness specimens, and the influence of a soft sealing layer on the deflection of
the specimen measured in the test (affecting the modulus determination).
4.3
Summary of International Scan Findings in the Pilot Study
The utilities interviewed for the international scan conducted under the previous EPA pilot study reported
a clear trend in the quality of CIPP work (EPA, 2012). Early installations did suffer from problems such
as wrinkling, blistering, and poor reopening of lateral connections, but these issues have been reduced as
installers gain experience. The need for trained and experienced installers and for clear and proven
installation procedures properly followed was mentioned by several utilities as being key to successful
installation. The utilities commented that the curing and cooling cycle is the element of the process that
requires closest supervision and monitoring. This is because contractors try to save time in this stage, and
this can result in inadequate curing, leading to problems of service life.
The utilities typically used post-installation CCTV surveys and/or an I/I test for in-situ performance
testing. The performance test is generally an in-situ water tightness test to look for exfiltration. Most, but
not all, of the utilities take samples from the installed liners for testing to verify that the installation meets
the specification requirements. The liner parameters that may be tested were: flexural strength, flexural
modulus, tensile strength, tensile modulus, water tightness, hardness and thickness. In addition to the
process verification and post-works inspections, there is generally a contractual requirement that the
contractor provide a warranty for the work.
Of the utilities interviewed, four had taken samples for testing from CIPP installations after a period in
service, one had undertaken CCTV surveys after 10 and 15 years in service, and had done so after 12
years of service in one line. In general, the findings from these investigations after a period in service had
indicated that there was no serious deterioration in performance of the CIPP linings. None of the findings
-------
had raised concerns over the service life, and those defects found were often considered to be installation
issues rather than inherent weaknesses of the products themselves. However, cleaning with high pressure
water jets was noted to be a potential cause of liner damage. More details on the findings of the
international scan are presented below in Sections 4.4 and 4.5.
4.4
European Studies
Lystbaek (2006, 2007) describes a project initiated in 1999 to follow up on the field performance of CIPP
liners installed since the early 1980s in Aarhus, Denmark. Five different installations were included in
the follow up with a total of six samples and it was intended to repeat the testing of these installations at
five yearly intervals (Table 4-4). All the liners included in the sampling had been installed in 1991 to
1992. The host pipes were at depths of 1 to 4 m (3 to 13 ft) in a residential area with light traffic and a
normal residential wastewater stream.
Table 4-4. Retrospective Liner Sampling in Denmark
Sample
Pipe 1
Pipe 2
Pipe3
Pipe 4
PipeS
Pipe 6
Impregnation
No.
575/92
574/92
574/92 A
044/91
345/92
050/91
Installed
Aug 27-28,
1992
Aug 27-28,
1992
Aug 27-28,
1992
Jan 28, 1991
June 1, 1992
Jan 30, 1991
First Sampling
16-17 Nov
1999
16-17 Nov
1999
16-17 Nov
1999
4-5 Apr 2000
4-5 Apr 2000
None
Second
Sampling
1 1 Apr 2005
8 Apr 2005
1 1 Apr 2005
1 1 Apr 2005
8 Apr 2005
26 Apr 2005
Diameter/
Wall
thickness
200 mm/6
mm
200 mm/6
mm
200 mm/6
mm
400 mm/9
mm
250 mm/6
mm
500 mm/9
mm
Source: Lystbaek, 2007
The various quality parameters for CIPP lining considered in the paper are shown in Table 4-5 together
with their relation to International and European standards. The referenced paper provides a discussion of
their applicability and value.
Some of the test results reported in the paper are highlighted in Tables 4-6 and 4-7. It was noted that the
samples taken at the time of installation were unrestrained samples taken in the manhole, whereas the
study samples were recovered from the pipe itself.
The modulus values for all three sets of tests were well in excess of the 250,000 psi minimum modulus
required in ASTM F1216. Due to the sample differences noted above, the paper author focused on the
comparison of the 1999-2000 data with the 2005 data and did not find any clear trends (some modulus
values increased and some decreased). Likewise, the density values varied slightly across the samples
and test periods, but no overall trends could be observed and all of the densities were within a range of
32
-------
1.15 g/cm3 to 1.29 g/cm3. Most (but not all) of the samples showed an increase of water absorption over
the 14-year service period, but in no case did the water absorption exceed 1.5% by weight.
The 50-year creep modulus testing indicated that the mean long-term modulus across all of the samples
recovered in 1999-2000 was 303,274 psi with a coefficient of variation of 0.13. The 2005 test results
gave a mean long-term modulus of 312,121 psi with a coefficient of variation of 0.19. The 1999-2000
testing indicated an effective 50-year long-term modulus at 59% to 65% of the short-term modulus. The
2005 testing indicated a range of 50% to 71% for the same ratio. For Sample 1 only, the 1999-2000
testing was extended to 20,000 hours to allow an extrapolation of the creep test results to a 100-year
effective modulus. The testing for this sample indicated that the ratio of the 100-year effective long-term
modulus to the short-term modulus was 55%.
33
-------
Table 4-5. Application of Quality Parameters and Test Standards
Quality Parameters
Wall thickness
E modulus (3 point)
Flexural stress er,
fb
Flexural strain e.
jb
Water Absorption
Density
Ring E modulus (wet)
Ring E modulus (dry)
Water content
Residual Styrene
Creep Modulus
Root infiltration
Self-cleaning ability
Coefficient of
variation*
Testing
Standard
ISO 178
ISO 178
ISO 178
ISO 62
EN 1228
EN 1228
ISO 4901
EN 761
CCTV
CCTV
Structural
Design
X
X
X
X
X
X
X
Operation of
the System
X
X
Specific for the
Product
X
X
X
Source: Lystbaek, 2007
* Long-term E modulus as 50-year values.
Italicized parameters indicate data from the original installation are available.
Table 4-6. Three-Point Flexural Test Data (ISO 178)
Average
Values
Pipe 1
Pipe 2
PipeS
Pipe 4
Pipe 5
Pipe 6
E modulus (psi)
19911
1992
379274
378403
378403
347655
404800
-
1999/
2000
380434
421189
458464
597700
541716
-
2005
561296
456434
474998
502266
498059
536204
Flexural Stress (psi)
1991/
1992
5656
5366
5366
5802
6237
-
1999/
2000
5802
5366
5076
7107
6382
-
2005
5482
5091
5743
6643
6425
6730
Flexural Strain (%)
1991/
1992
1.70
1.60
1.60
2.30
2.00
-
1999/
2000
1.60
1.30
1.10
1.20
1.20
-
2005
0.98
1.18
1.25
1.35
1.31
1.30
Source: Lystbaek, 2007
50 mm wide samples - weft direction, support 100 mm; values converted to Imperial Units.
Table 4-7. Average Water Absorption (ISO 62) and Density
Sample
Pipe 1
Pipe 2
Pipe 3
Pipe 4
Pipe 5
Water Absorption (% of weight)
1991-1992
0.80
0.70
0.70
0.69
0.93
1999-2000
0.90
1.40
1.10
0.17
0.61
2005
1.12
1.12
1.50
0.43
1.04
Density (g/cm )
1991-1992
.28
.22
.22
.16
.15
1999-2000
.28
.23
.16
.28
.25
2005
.29
.20
.20
.25
.18
34
-------
I Pipe 6 I - I - I 0.99 I - I - I -
Source: Lystbaek, 2007
CCTV inspection of the selected pipe sections was carried out prior to the original renovation and at
subsequent sampling periods. Prior to renovation, pipe failures, displaced joints and infiltration of roots
could be seen. The root infiltration had resulted in obstructions and sedimentation. Since the renovation,
it was reported that there have been no signs of root infiltration or critical obstructions in the sampled
installations. The conclusions of the paper were as follows:
"The test results verify that the longevity of cured-in-place pipes can by all indications be
expected to be minimum 100 years. There are further signs that the ring stiffness test of
samples taken at the time of installation is representative for an assessment of the CIPP
longevity. The product variation over the length of the CIPP installation is an area
requiring further study. Simulated tests have consequently been implemented in order to
determine the size of the variation and also to find the sampling place that is most
representative for the installation. "
It was reported that long-term laboratory testing to establish the 100-year effective creep modulus values
was being carried out on the 2005 samples and that the liners would continue to be resampled every 5
years (Lystbaek, 2007).
In a study by Bosseler and Schliiter (2002), 15 CIPP rehabilitation liners (including hot water, steam and
UV cure) installed from 1991 to 1998 were evaluated and for three of the liners, 2 m long sections of the
host pipe and liner were removed for further evaluation and testing.
Problems, issues, and findings from the study included the following:
• Quality tests and construction site specimens were not made or taken as a rule in the
installations evaluated in this study. Since the quality achieved at the time of the repair was
not checked and documented, it was difficult to estimate the maximum utilization period of the
repaired sections considered.
• Damage was noted in CCTV inspection of all the sections. As a rule, these were limited
spatially and in most cases were clearly the result of individual execution errors such as crease
formation in the longitudinal and annular directions and erroneous bonding of lateral inlets.
• For eight sections, comparison could be made with a post-installation inspection video. The
majority of the above damage could already be recognized immediately after installation.
When compared with the new inspection data, it was not possible to notice any mentionable
change in the liner through the effects of operation.
• The damage intensity and frequency in the sections studied were categorized as slight on the
basis of the inspection results. However, leakage and tree root issues were noted at lateral
connections and manhole terminations.
• The sectional leakage tests on the sections revealed satisfactory results in seven out of 10
instances.
• Leakage test results on connection liners were poor.
• The newer construction measures showed a lower quantity of damage patterns resulting from
execution errors (i.e., creases in the lateral, longitudinal and annular directions as well as
incorrect connections). This indicated improvement of installation quality over time.
35
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• Some issues were seen in terms of obtaining the material values used in the static calculations
under certain circumstances.
The Bosseler and Schliiter paper led to significant ongoing work by the IKT on the testing and evaluation
of rehabilitation technologies. More information on the range of testing carried out by the IKT can be
found at www.ikt.de/english. The series of reports on the evaluation of CIPP liner quality are of
particular interest in the context of the current report. References include IKT (2004, 2011) and Waniek
and Homann (2006, 2007, 2008, and 2009). These reports provide test results on liner properties at
installation, including flexural modulus, flexural strength, liner thickness, and water tightness. The full
results are not summarized here, but the test results on liner thickness are summarized in an extension of
the table produced by Harada et al. (2011) and shown in Table 4-1. It is clear that, in Germany, the
percentage of liners installed at the design thickness has been increasing more or less steadily since 2004.
Gumbel (2009) reviews the international development of testing standards for CIPP and compares
practices between Europe and North America. Key topics of the paper are the determination of long- and
short-term stiffness characteristics coupled with the use of ring or three-point flexural tests. Field
sampling and test selection as a function of liner size and wall structure are reviewed as well as some
further tests proposed for use in estimating long-term performance and/or providing enhanced QC.
Summarizing information from the international scan carried out in the pilot study (EPA, 2012), the
overall impressions of CIPP suitability were reported by the different European countries as:
• In Germany, Gottingen now considers CIPP to be an excellent long-term repair technology
with a service life of 50 years and that it can make individual pipes watertight. But it does not
meet their requirement of achieving a permanent, watertight network due to the problems of
sealing the liners at service connections and manholes. Leverkusen had concerns over the
resistance of CIPP to water jetting used for cleaning. Their view was that quality of
installation has improved significantly since the 1990s, especially in areas such as reopening
of laterals. Testing has also improved so the overall standard has improved dramatically.
Leverkusen was considering introducing infrared spectroscopy to its type of testing to ensure
that the correct resins are used.
• In the UK, Thames Water is satisfied that its established system, using preferred contractors,
delivers value for money. This experience is considered important in eliminating installation
defects which are the main source of performance problems later on. The experience of
Severn Trent Water also has been generally good. They report some problems with liner
stretch, missed connections, wrinkling and re-rounding severely deteriorated pipe prior to
lining.
• In France, the Agglomeration de Chartres uses CIPP to reinforce sewers where there is high
risk of root penetration. The condition of lateral connections and frequent displaced pipes
means that CIPP is considered ineffective in combating I/I. The Agglomeration des Hauts-de-
Bievre considers CIPP to be a reliable method that will remain the main one used for sewer
rehabilitation works. They now enter into annual contracts with one contractor only to ensure
experience and quality, and do not use a competitive tender for each project. In 14 years of
CIPP usage, only two projects were considered to have failed: a 200 m (656 ft) installation at a
very difficult location could not be completed; and a 500 m (1,640 ft) installation was taken
out because of poor installation and curing control. This represented approximately 2% of the
total length installed to date.
36
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4.5 Asian and Australian Studies
No specific papers were found in the literature search from Asia and Australia that discussed retrospective
evaluation data or approaches. However, summarizing information from the international scan carried
out in the pilot study (EPA, 2012), the overall impressions of CIPP suitability were reported by some
different countries as follows:
• In Singapore, more than 80% of the lining undertaken to date is CIPP and this was expected to
continue to be the case in current and future phases of work. The specifics of the methods
used have evolved to meet the needs of a tropical climate and the rigorous performance
requirements of the Public Utilities Board (PUB) for Singapore. As a result, PUB considers
CIPP to be a viable, long-lasting means of achieving a watertight sewerage system.
• In Australia, the situation is different because of the predominance of polyethylene and PVC
fold-and-form and spirally-wound linings. Sydney Water has used such plastic liners for
rehabilitation for over 25 years. Use of CIPP has been limited mainly to patches, private
sewers and laterals and, more recently, junctions. Queensland Urban Utilities in Brisbane also
makes greater use of PVC and polyethylene-based lining systems than of CIPP. It shares the
concerns of the other utilities over jetting for cleaning in CIPP-lined pipes. The utility
considers that CIPP is a valuable technology when the right product is used in the right
conditions, but that it is important to understand its limitations and risks.
• In Japan, at a site level, CCTV examination, measurement, sampling, and testing are required
on all installations in accordance with Japan Sewerage Works Agency regulations and many
sites are re-examined after one year. Regarding quality controlled testing of liner materials
after curing, most municipalities are requesting a test of the actual cured liner. However, their
requirement varies municipality by municipality.
4.6 Summary
The above findings indicated that CIPP rehabilitation is considered, by the owners using it, a reliable
technique with a good track record but that it should be recognized that CIPP mainline rehabilitation does
not generally ensure a "watertight" sewerage system. As a site-constructed lining process, a number of
defects can occur at the time of installation which must be guarded against and design decisions about the
features and/or implementation of the CIPP method may affect the ability of the CIPP approach to
provide a full solution to obtaining a leak-free sewer system.
Few problems have been found so far with long-term performance except that maintenance practices must
be adapted to avoid damage to the liners. The data presented in the reported studies and the experiences
related by the owners involved are considered, along with the findings from the current study in Section 5
of this report.
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SUMMARY RESULTS AND COMMON THREADS
The detailed results for the current case studies are presented in Appendix B for CIPP liners and in
Appendix C for other rehabilitation technologies. This section is intended to summarize the test results
and to look for any indications of liner deterioration and/or the overall longevity of the liners that may be
expected. The CIPP test results from the current 13 sites are presented in Section 5.1; these CIPP results
are integrated with those from the previous four sites from the pilot study in Section 5.2 where trends of
properties with liner age and correlations with other liner properties also are explored. The use of the
database of test results is explored forthe CIPP samples in Section 5.3. The test results for the other
rehabilitation technologies evaluated are discussed in Section 5.4.
5.1
Current CIPP Case Studies
Table 5-1 gives the average results for key parameters tested for each CIPP site in the current study.
Table 5-1. Summary of Key Laboratory Test Results from Current Case Studies
Location
Edmonton 1
(10 in.)
Edmonton 2
(8 in.)
Houston 1
(21 in.)
Houston 2
(18 in.)
Indianapolis
(42 in.)
Nashville 1
Dunston (8 in.)
Nashville 2
Wyoming (8 in.)
New York 2
(15 in.)
New York 3
(12 in.)
Northbrook
(12 in.)
Winnipeg 1
Richard (30 in.)
Winnipeg 2
Kingsway (18 in.)
Winnipeg 3
Mission (30 in.)
Liner
Age
(years)
19
19
17
17
25
19
9
23
24
34
34
34
28
Average Values
ASTM D638 (psi)
Tensile
Strength
3,241
3,653
3,409
3,252
2,718
3,436
2,672
3,729
3,275
4,402
(a)
(a)
(a)
Tensile
Modulus
436,710
510,132
465,322
450,985
351,294
375,807
400,926
554,101
324,406
433,541
(a)
(a)
(a)
ASTM D790 (psi)
Flexural
Strength
6,135
6,816
6,893
7,204
4,712
6,832
5,497
7,978
7,200
7,761
8,592b
6,779b
4,469b
Flexural
Modulus
331,333
364,788
337,638
338,565
237,264
301,724
282,460
477,609
285,177
322,360
452,134b
323,930b
245,753b
Specific
Gravity
1.25
1.25
1.17
1.18
1.08
1.14
1.21
1.31
1.15
1.19
1.21
1.14
1.07
Shore D Hardness
Inner
68.6
68.2
61.2
65.4
57.4
65.2
64.6
73.3
57.7
65.6
57.4
54.1
57.3
Outer
78.1
79.2
61.3
75.7
65.7
72.2
67.4
72.1
58.7
76.0
65.8
60.9
64.9
Thickness
(mm)
4.7
4.8
10.7
11.0
22.2
5.6
7.1
7.3
7.1
4.7
6.6
6.7
22.8
(a) Samples received at TTC not large enough to test for this parameter.
(b) Samples received at TTC not large enough to test for this parameter but test data for the liners was received from City of Winnipeg.
See also Table 4-2 in this report showing the data from Macey et al. (2013).
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A full set of results were obtained from 10 sites in the U.S. and Canada with additional test results from
three sites in Winnipeg for which the sample sizes received at the TTC precluded ASTM D638 and D790
testing as a part of this study. For the flexural properties of the Winnipeg samples, however, such testing
had been carried out by the city itself and flexural strength and flexural modulus test data were provided
to the project. These external data are included in the database and in the presentation and discussion of
the results. Summary flexural data also are reported in Macey et al. (2013) for Winnipeg Samples 1 and 2
(see Table 4-2).
5.1.1 Visual Inspection. The visual condition of all of the liners in the current study (with the
exception of the New York Sample 1) was deemed to be excellent. New York Sample 1 was found to be
largely unsaturated with resin and was not included in the determination of other physical properties. A
new sample was added in New York (New York Sample 3) to replace this sample.
The sealing layer was found to be in place in some sites (e.g., in the two 20-year old Edmonton samples
and in the 34-year old Winnipeg 2 sample), but missing for others (e.g., the 23-year old New York
Sample 2).
5.1.2 Annular Gap. Annular gaps were measured wherever possible in the field and/or in the
laboratory. It was not always possible to measure the field values due to site configurations and/or
conditions. In addition for panel samples, where the field samples were cut out from within the liner,
annular gap measurements were not possible in the laboratory. The available observations are
summarized in Table 5-2.
The liners were generally quite tight to the host pipe and the annular gaps did vary around the
circumference of the host pipe. Where annular gaps could be measured, they were mostly less than 0.08
in. (2 mm) and often much less than this value. The Northbrook liner had a localized region around the
circumference with a maximum annular gap of about 0.42 in. (10.7 mm). This was noted to occur at
approximately the 5 o'clock position within the liner.
Table 5-2. Annular Gap Observations for the Current Case Studies
Sample
Edmonton 1 (10 in.)
Edmonton 2 (8 in.)
Houston 1 (21 in.)
Houston 2 (18 in.)
Indianapolis (42 in.)
Nashville 1 Dunston (8
in.)
Nashville 2 Wyoming (8
in.)
New York 2 (15 in.)
New York 3 (12 in.)
Northbrook (12 in.)
Winnipeg 1 (30 in.)
Winnipeg 2 (18 in.)
Winnipeg 3 (30 in.)
Annular Gap Observations
Either tight or with annular gap less than 0.04 in. (1
Either tight or with localized annular gap up to 0.08 in.
mm)
(2mm)
N/A
N/A
Annular gap less than 0.02 in. (0.4 mm)
Annular gap less than 0.03 in. (0.8 mm)
Annular gap less than 0.05 in. (1.2 mm)
Either tight or less than 0.01 in. (0.2 mm) (measured in field)
N/A
Varies from 0.01 in. (0.2 mm) to localized value of 0.42
mm) at 5 o'clock position
in. (10.7
N/A
N/A
N/A
N/A = Sample only retrieved and no field measurements possible
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5.1.3 Soil and Pipe Sediment pH Values. The pH values of soil samples and any sediment inside
the CIPP liner were measured for many of the sample sites and the results are tabulated in Table 5-3. The
pH values for sediment retrieved from inside the pipe varied from approximately 4 to 11. The pH values
for the external soil samples varied from approximately 4 to 9. There was no consistency in the results as
to whether the pH values were higher inside the pipe or outside the pipe. Together with the depth of the
host pipe (affecting potential traffic and groundwater loadings) and any comments from the municipality
about their impressions of the severity of the environmental condition, these data provide only a
preliminary assessment of the lifetime environmental exposure for the liner. It is not considered,
however, that the impact of any severe exposure conditions were captured in the retrospective samples
recovered to date.
Table 5-3. Measurements of pH for the Current Case Studies
Sample
Edmonton 1 (10 in.)
Edmonton 2 (8 in.)
Houston 1 (21 in.)
Houston 2 (18 in.)
Indianapolis (42 in.) (2
panels)
Nashville 1 Dunston (8 in.)
Nashville 2 Wyoming (8 in.)
New York 2 (15 in.)
New York 3 (12 in.)
Northbrook (12 in.)
Winnipeg 1 (30 in.)
Winnipeg 2 (18 in.)
Winnipeg 3 (30 in.)
Inner Pipe Sediment
PH
7 to 8
N/A
4 to 5
6 to 7
5 and 6 to 7
10 to 11
9 to 10
N/A
N/A
6 to 7
N/A
N/A
N/A
External Soil pH
N/A
8 to 9
5
4 to 5
6 to 7 and 6 to 7
N/A
6 to 7
N/A
N/A
6 to 7
N/A
N/A
N/A
N/A = Sediment or soil sample not available for testing
5.1.4 Liner Ovality. Liner ovality was measured whenever a full circumference liner sample
could be retrieved. The measurement procedures are described in Appendix B. The ovality measurement
results are provided in Table 5-4.
The maximum liner ovality measured was 5.75% for an individual reading within one sample. The
minimum ovality measured was around 0.35%. Liner ovality reduces the resistance to buckling of an
oval liner compared to an otherwise equivalent circular liner and this effect is included in the design
equations in ASTM F1216. If the ovality of a host pipe is significant, then the in-place ovality should be
measured. Otherwise, a minimum value of ovality can be assumed to cover unmeasured variations and
conditions.
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5.1.5 Liner Thickness. The liner thicknesses for the 13 sites in the current study were measured
and the results presented in Table 5-5. The thinnest liner was 4.6 mm thick for a 19-year old liner in a 10
in. inner diameter host pipe at a depth of approximately 9.8 ft below ground in Edmonton. This liner was
found to have a flexural strength of 6,135 psi and a flexural modulus of 331,333 psi both still well above
the ASTM requirements at installation. The thickest liners were 22.8 mm for Winnipeg Sample 3 in a 30
in. diameter host pipe and 22.2 mm in the Indianapolis sample in a 42 in. diameter host pipe. Both of
these thickest liners were found to have low specific gravities and low strength and modulus properties as
discussed in Section 5.1.6.
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Table 5-4. Measured Liner Ovality for the Current Case Studies
Sample
Edmonton 1 (10 in.)
Edmonton 2 (8 in.)
Houston 1 (21 in.)
Houston 2 (18 in.)
Indianapolis (42 in.)
Nashville 1 Dunston (8 in.)
Nashville 2 Wyoming (8 in.)
New York 2 (15 in.)
New York 3 (12 in.)
Northbrook (12 in.)
Winnipeg 1 (30 in.)
Winnipeg 2 (18 in.)
Winnipeg 3 (30 in.)
Liner Ovality
2.7% to 4.3%
4.5% to 5. 75%
1.4%
1.7%
N/A
3.7%
3.6%
N/A
N/A
0.33% to 0.38%
N/A
N/A
N/A
N/A = Ovality measurement not possible because only a panel sample was available
For most of the liners, the design/specified thickness of the liner at the time of installation could not be
retrieved from the records. Where this thickness is available, the measured thickness is compared with
the specified value in Table 5-5. Two liners had thicknesses less than that specified (at 78% and 93% of
the specified value) and two liners had thicknesses more than that specified (at 110% and 112% of the
specified value).
Table 5-5. Measured and Specified Liner Thickness for the Current Case Studies
Sample
Edmonton 1 (10 in.)
Edmonton 2 (8 in.)
Houston 1 (21 in.)
Houston 2 (18 in.)
Indianapolis (42 in.)
Nashville 1 Dunston (8
in.)
Nashville 2 Wyoming (8
in.)
New York 2 (15 in.)
New York 3 (12 in.)
Northbrook (12 in.)
Winnipeg 1 (30 in.)
Winnipeg 2 (18 in.)
Winnipeg 3 (30 in.)
Measured Thickness
(mm)
4.66 ±0.21
4.76 ±0.21
10.65 ±0.35
10.95 ±0.23
22.39 ±0.21; 21. 92 ±
0.21
5. 60 ±0.32
7.05 ±0.28
7.27 ±0.26
7.09 ±0.27
4.66 ±0.21
6.60 ±0.68
6.69 ±0.31
22.83 ±3. 11
Specified
Thickness
(mm)
5.0
-
-
-
-
-
-
-
-
6.0
6.0
6.0
-
Average as Percent
of Specified Value
93%
-
-
-
-
-
-
-
-
78%
110%
112%
-
Note: The as-specified thickness was often not available from municipalities for the retrieved samples.
42
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5.1.6 Specific Gravity. The specific gravity of all 13 liners included in the current study was
determined using ASTM D792 and the results are listed in Table 5-1. The average specific gravity
determined for each of the 13 liners varied from a low of 1.07 to ahigh of 1.25. There is no requirement
for a particular specific gravity for a CIPP liner, but as can be seen in Section 5.2.7, the specific gravity of
a liner does show correlation with the structural liner parameters and can be an indication of the quality of
the liner. The lowest specific gravities (1.07 and 1.08) were measured for the two thickest liners (22.8
mm and 22.2 mm respectively). These liners (the Indianapolis liner in a 42 in. diameter host pipe and the
Winnipeg 3 sample in a 30 in. diameter host pipe) both had the lowest flexural strength and flexural
modulus values in the current study. This may indicate that thicker liners demand particular attention to
make sure that the appropriate specific gravities and strength/modulus properties are achieved.
Additional measurements of porosity were tried using a mercury vapor intrusion test, but these tests
produced unrealistically high specific gravities and were not included in the results presented. It is
hypothesized that this method is not appropriate for measuring the porosity of CIPP liner materials under
substantial pressure as the liner has tendency to be compressed (e.g., behaving like a sponge).
5.1.7 Tensile Properties. The tensile properties of the liners from 10 sites in the current study
were evaluated according to ASTM D638 and are listed in Table 5-1. The three samples received from
Winnipeg did not have sufficient material to complete the tensile testing at the TTC according to ASTM
D638. The average tensile strengths from each site varied from 2,672 psi to 4,402 psi and the average
tensile moduli from each site varied from 324,406 psi to 554,101 psi. The mean and standard deviation
for the tensile strength from all samples in the current study was 3,379 psi and 498 psi and the mean and
standard deviation for the tensile modulus was 430,322 psi and 70,470 psi, respectively. For these non-
pressure pipe installations, there is no requirement for tensile properties in ASTM F1216 at the time of
installation.
5.1.8 Flexural Properties. The flexural properties of the liners from 13 sites in the current study
were evaluated according to ASTM D790 and are listed in Table 5-1. The three samples received from
Winnipeg did not have sufficient material to complete the flexural testing at the TTC according to ASTM
D790. However, for these sites, the test data for flexural properties obtained through third party testing
by the City of Winnipeg were made available. Also, for two of the sites (Winnipeg 1 and Winnipeg 2)
minimum and maximum flexural properties had been published in Macey et al. (2013). These data are
provided in Table 4-2 as part of the discussion of Canadian retrospective evaluation research. From the
TTC testing plus the Winnipeg provided data, the average flexural strengths for each site varied from
4,469 psi to 8,592 psi and the average flexural moduli from each site varied from 237,264 psi to 477,609
psi. The mean and standard deviation for the flexural strength from all samples in the current study was
6,682 psi and 1,211 psi and the mean and standard deviation for the flexural modulus was 330,825 psi and
70,060 psi, respectively. ASTM F1216 does provide minimum values for each of these parameters at the
time of installation.
For the flexural strength, all but one of the average test values met the minimum ASTM flexural strength
at installation requirement of 4,500 psi even after 5 to 34 years of service. This low value was 4,469 psi -
only just below the current ASTM requirement after 28 years of service. The oldest liner had a flexural
strength of 7,761 psi.
For the flexural modulus, all of the average test values except two met the minimum ASTM flexural
modulus at installation requirement of 250,000 psi after 5 to 34 years of service. The Winnipeg 3
(Mission) sample had an average modulus of 245,753 psi that exceeded the flexural modulus requirement
at the time of its installation (240,000 psi), but is slightly below the current ASTM specification value of
250,000 psi. The other value not meeting the ASTM installation standard was from a 25-year-old liner in
Indianapolis, which had the largest diameter in the current study (42 in.), had the deepest depth recorded
43
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(20 ft) and was the second thickest liner in the current group (22.2 mm). The oldest liner tested (the
Northbrook liner with 34 years in service) had a flexural modulus of 322,360 psi.
5.1.9 Shore D Hardness. The Shore D Hardness values for both the inner and outer surfaces of
the retrieved liner samples were determined for all 13 liners included in the current study using ASTM
D2240 and the results are listed in Table 5-1. For the liners in the current study, the hardness of the inner
surface was almost always lower than the hardness of the outer surface (sometimes marginally and
sometimes significantly). The inner hardness value ranged from a low of 54.1 to a high of 73.3 and the
outer hardness value ranged from 58.7 to 79.2. It was postulated in the pilot study that differences
between the inner and outer hardness values in an older liner could be an indication of deterioration of the
CIPP liner due to the effects of the service conditions within the sewer. Such an evaluation is greatly
complicated by the use of the sealing layer during the installation process for the CIPP liner. This may or
may not be eroded or hydrolyzed in an older liner and also its presence during wet out and curing may
impact the local hardness properties of the CIPP resin. This issue is explored a little further in Sections
5.2.4 and 5.2.9 because a test for the inner surface hardness of a CIPP liner could be a useful non-
destructive in-service test for a liner if appropriate correlations could be established.
5.1.10 Short-Term Buckling Tests. Short-term buckling tests were able to be conducted on three
of the retrospective samples (Table 5-6). The tests provide an indication of the continued structural
capability of the full circumference of the liner, but the results cannot be interpreted directly in terms of
design parameters. For practical test reasons, the liners are inserted in a new host pipe in the laboratory
with a significant annular gap (approximately 1 in.), which will significantly lower the buckling resistance
of thin liners. The lengths of the buckling test sections also are too short to be able to avoid end effects in
the testing process. Such end effects are likely to increase the buckling resistance of the liner in the
laboratory test. Finally, the buckling tests measure a short-term buckling resistance rather than the long-
term buckling resistance. The long-term buckling resistance is affected by creep of the liner over time.
Nevertheless, all of the buckling results for these 19 to 34 year-old liners still exceeded the resistance that
would be necessary to resist a water table at the ground surface at each site.
Table 5-6. Short-Term Buckling Test Results for the Current Case Studies
Sample
Edmonton 1 (10 in.)
Edmonton 2 (8 in.)
Houston 1 (21 in.)
Houston 2 (18 in.)
Indianapolis (42 in.)
Nashville 1 Dunston (8 in.)
Nashville 2 Wyoming (8 in.)
New York 2 (15 in.)
New York 3 (12 in.)
Northbrook (12 in.)
Winnipeg 1 (30 in.)
Winnipeg 2 (18 in.)
Winnipeg 3 (30 in.)
Maximum Pressure Sustained in
Short-term Buckling Test (psi) (water
head)
12 (28 ft)
20 (46 ft)
N/A
N/A
N/A
N/A
N/A
N/A
N/A
5 (11. 5 ft)
N/A
N/A
N/A
N/A = Buckling test not carried out due to the nature of the sample (e.g., panel sample or sample length)
44
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5.1.11 Glass Transition Temperature. The glass transition temperature (Tg) represents the
temperature region in which the resin transforms from a hard, glassy solid to a viscous liquid. As a
thermosetting resin cures, the Tg increases and the heat of cure decreases. These changes can be used to
characterize and quantify the degree of cure of the resin system. In general, an increase in the Tg is a
function of curing and represents the increase in the molecular weight of the resin system (Perkin-Elmer,
2000). Table 5-7 summarizes the average Tg values for the CIPP samples from the current case studies.
Table 5-7. Average Glass Transition Temperature for the Current Case Studies
Sample
Edmonton 1 (10 in.)
Edmonton 2 (8 in.)
Houston 1 (21 in.)
Houston 2 (18 in.)
Indianapolis (42 in.)
Nashville 1 Dunston (8 in.)
Nashville 2 Wyoming (8 in.)
New York 2 (15 in.)
New York 3 (12 in.)
Northbrook (12 in.)
Winnipeg 1 (30 in.)
Winnipeg 2 (18 in.)
Winnipeg 3 (30 in.)
Average Tg (°C)
115.48
112.91
119.91
119.69
125.23
120.37
109.43
87.28
90.10
105.74
122.28
76.72
129.24
5.2
Synthesis of Current CIPP Data with Pilot Study Data
In this section, the laboratory test data for the 13 sites in the current study are combined with the four sites
(five test samples) from the pilot study for further analysis. These analyses will use the average test
results for each parameter for each site, plus some calculated parameters as shown in Table 5-8 (note that
the test data from Table 5-1 are repeated within Table 5-8 for convenience). All of the individual test data
from this retrospective evaluation project (pilot study and current sites) have been entered into the
database described in Section 2 and an exploration of the retrospective data in terms of data relationships
and variability within sites and across all CIPP sites will be provided in Section 5.3. The analysis in this
section will concentrate on the broad interpretation of the results of the retrospective testing so far.
5.2.1 Flexural Properties. Since the flexural properties of a gravity CIPP liner have specified
minimum values in ASTM F1216, these are typically considered the key test parameters. The liner
sample ages mostly ranged from 17 to 34 years in service with two younger liners included (with 5 years
and 9 years in service).
The average flexural modulus values across the 17 sites (18 samples) ranged from a low of 206,805 psi to
a high of 477,609 psi. The mean and standard deviation of the average test results from each sample were
317,503 psi and 70,171 psi, respectively. The percent standard deviation for the flexural modulus was
higher at 22.1% than for the flexural strength (16.2%), the tensile modulus (16.0%) and tensile strength
(13.7%). Four of the 18 average test values fell below the ASTM F1216 requirement of 250,000 psi, but
there is no indication that these low values represent deterioration of the liner as opposed to a poor liner
quality in the as-installed liner. In the Winnipeg Mission 30 in. sample case, the flexural modulus value
45
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was above the value specified at the time of installation. The Denver 48 in. (upstream) liner was noted to
have significant variation in localized liner properties and the flexural modulus shown for the upstream
liner is the average of two sets of flexural test samples that were tested. When the upstream and
downstream samples are averaged together for the Denver 48 inch site, the combined average value is
above the ASTM F1216 requirement. Thus, it can be said that out of the 17 separate "sites" tested, only
two of the liners did not meet the average flexural modulus values that had been required at the time of
installation. It is not possible to fully determine if the low values represent ongoing deterioration or poor
liner properties that had existed since the time of installation.
The flexural strength values across the 17 sites (18 samples) ranged from a low of 4,469 psi to a high of
8,592 psi. The mean and standard deviation of the average test results from each sample were 6,594 psi
and 1,066 psi, respectively. The percent standard deviation for the flexural strength was 16.2%. All of
the samples but one had an average test value that met the ASTM requirement of 4,500 psi. It was noted
regarding the Winnipeg liner that did not meet the ASTM value (see Section 4.2) that the "low flexural
strength value was associated with a liner with visible installation related issues."
5.2.2 Tensile Properties. For the 15 sites with average tensile test results, the mean and standard
deviation for tensile strength were 3,323 psi and 455 psi, respectively. The mean and standard deviation
for tensile modulus were 413,460 psi and 65,961 psi, respectively. Similarly to the flexural results, the
percent standard deviation was less for the strength properties (13.7%) than for the modulus properties
(16.0%). For gravity sewers, there is no ASTM test value requirement.
5.2.3 Specific Gravity. For the 18 sites with specific gravity test results, the average specific
gravity was 1.16 and the standard deviation was 0.07. The percent standard deviation was 5.7%, which
was the lowest among the various test parameters measured. In the pilot study report (EPA, 2012),
Section 5.4.4 provides a discussion and calculation of theoretical liner specific gravity values depending
on the porosity, use of filler (which may be used to increase flexural modulus) and proportions of resin
and felt. With typical proportions of resin and felt and no filler, the theoretical specific gravities for the
liner range from 1.075 for a porosity of 10% to 1.191 for no porosity. For the use of talc filler with 12%
by volume, the respective values would range from 1.224 for 10% porosity to 1.360 for no porosity. In
these calculations, it is assumed that the felt fibers occupy 14% of the final resin volume. The remaining
volume is occupied by resin, any filler that is used, and air (the result of porosity in the liner). When no
filler is used and the porosity approaches 20%, the specific gravity of the liner will fall below 1.0 and a
liner sample will float. This is sometimes useful as a simple test for whether a liner has a very high
porosity or not.
5.2.4 Shore D Hardness. Examining the full set of Shore D hardness values (18 samples) for both
the inner and outer surfaces of the retrieved liner samples did not affect the interpretation of the results
presented in Section 5.1.9. The hardness of the inner surface was still almost always lower than the
hardness of the outer surface (sometimes marginally and sometimes significantly). The range of hardness
values also remained unchanged, i.e., the inner hardness value ranged from alow of 54.1 to a high of 73.3
and the outer hardness value ranged from 58.7 to 81.4. Examining the difference between the inner and
outer hardness value, this change ranged from a low of-1.7% to a high of 25.7%. An examination of how
this variability might relate to the value of other parameter values is given in Section 5.2.9. It is noted
again here that such an evaluation is complicated by the use of the sealing layer during the installation
process for the CIPP liner. This may or may not be eroded or hydrolyzed in an older liner and also its
presence during wet out and curing may impact the local hardness properties of the CIPP resin.
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5.2.5 Liner Thickness. The thickness of the liner is a design parameter that is related to the
expected service parameters of the liner and the design procedures used at the time of the original liner
installation. However, several aspects of liner thickness have potential relevance to the interpretation of
liner deterioration. These include:
1. The extent to which the specified liner thickness was realized in the field;
2. The variation of liner thickness within a sample (relating to QC in the liner
preparation/installation or variations in installation conditions within the liner); and
3. The extent to which the design assumptions correctly reflected the actual in-service
conditions (e.g., the assumptions about the level of deterioration of the host pipe, the water
table assumptions and the actual versus assumed liner strength/modulus properties).
Only the first issue is examined here and in Section 5.2.10.
The liner thicknesses for the 13 sites in the current study were measured and the results presented in Table
5-8. For most of the liners, the design/specified thickness of the liner at the time of installation could not
be retrieved. However, two liners had thicknesses less than that specified (at 78% and 93% of the
specified value) and two liners had thicknesses more than that specified (at 110% and 112% of the
specified value). In the pilot study, four out of the five samples retrieved had liner thickness less than the
specified thickness, so the realization of the expected liner thickness in the field during installation is an
issue to watch in QA/QC procedures.
5.2.6 Key Liner Properties versus Age of Liner. Liners with service lives ranging from 5 to 34
years have been included in the study thus far. This provides an opportunity to examine whether there are
any clear trends of the change of liner properties with length of service. At this stage of the assembly of
retrospective evaluation data for CIPP liners, a number of issues make the evaluation of such trends
difficult:
• The relatively small number of samples available;
• The lack of equivalently measured parameters at the time of installation (which might provide
a real measure of change in properties); and
• The absence of information as to whether the measured properties after a portion of the
expected service life represent liner deterioration, poor QC in the installation or variation
among the as-installed liner properties.
Figure 5-1 shows the flexural modulus and tensile modulus measurements versus the age of the liner. It
includes the average flexural modulus data from each of the 18 samples retrieved across the current and
pilot study, plus the average tensile modulus data from 15 samples (excluding the Winnipeg sites). In
each case, the calculated linear regression trend line is slightly positive, i.e. both moduli increase with
age. However, the data show a large amount of scatter (R2 value less than 0.01 in each case as calculated
within Microsoft® Excel) and the lack of any obvious trend with age combined with the issues raised
above has suggested that adding trend lines would not add substantial value to the information presented.
In the following discussions, R2 values are provided to indicate the level of scatter and noted when they
exceed 0.5 in value. No "strong" correlations were found (e.g., with R2 values greater than 0.8).
Figure 5-2 shows the equivalent plot for flexural strength and tensile strength versus the age of the liner
for the same sample sets used in Figure 5-1. As was noted in terms of the lower percent standard
deviations of the strength data in Section 5.2.1 and 5.2.2, the measured strengths have less scatter than the
measured moduli and particularly so for the tensile strength but the calculated R2 values are still both
47
-------
below 0.05. There is still no clear relationship to the service life of the liner, although the calculated trend
lines both have a positive slope, i.e. both strengths tend to increase with age.
Figure 5-3 shows a plot of the measured specific gravity of the liner versus the age of the liner samples.
Since the graph is less cluttered, a linear trend line (calculated within Microsoft® Excel) has been shown
on the graph. The caveats discussed earlier as to whether any apparent trends with age are real still apply
and it also should be noted that the vertical axis of the graph in this case only starts at a value of 1.0 rather
than having its origin at 0. This makes the plot clearer, but accentuates the apparent variation of the trend
line. The R2 value is 0.0025 indicating the huge amount of scatter present.
Overall, there is nothing seen in the measurements to date to document a real trend of diminishing liner
properties with time. It should be noted that the main determinant of service life for CIPP liners is often
the time to failure via buckling of the liner. This is controlled by the creep properties of the liner through
an assessment of the "apparent long-term flexural modulus" of the liner. Under this design case, the liner
will still have a certain time to failure even if the short-term flexural modulus remains unchanged.
48
-------
Table 5-8. Measured and Calculated Average Test Parameters for the 18 Retrospective Samples
Location
Columbus 36 in.
Columbus 8 in.
Denver 8 in.
Denver 48 in. Downstream
Denver 48 in. Upstream
Edmonton 10 in.
Edmonton 8 in.
Houston 2 1 in.
Houston 18 in.
Indianapolis 42 in.
Nashville Dunston 8 in.
Nashville Wyoming 8 in.
NYC 15 in.
NYC 12 in.
Northbrook 12 in.
Winnipeg Richard 30 in.
Winnipeg Kingsway 18 in.
Winnipeg Mission 30 in.
Average
Standard Deviation
Percent Standard Deviation
Average Values per Site
D638 (psi)
Tensile
Strength
2,958
3,866
3,029
2,995
3,208
3,241
3,653
3,409
3,252
2,718
3,436
2,672
3,729
3,275
4,402
(a)
(a)
(a)
3,323
455
13.7
Tensile
Modulus
315,259
362,588
411,621
382,420
426,787
436,710
510,132
465,322
450,985
351,294
375,807
400,926
554,101
324,406
433,541
(a)
(a)
(a)
413,460
65,961
16.0
D790 (psi)
Flexural
Strength
6,039
6,416
6,756
7,031
5,575
6,135
6,816
6,893
7,204
4,712
6,833
5,497
7,978
7,200
7,761
8,592b
6,779b
4,469b
6,594
1,066
16.2
Flexural
Modulus
206,805
346,050
335,340
302,960
223,165
331,333
364,788
337,638
338,565
237,264
301,724
282,460
477,609
285,177
322,360
452,134b
323,930b
245,753b
317,503
70,171
22.1
Specific
Gravity
1.17
1.11
1.16
1.07
1.08
1.25
1.25
1.17
1.18
1.08
1.14
1.21
1.31
1.15
1.19
1.21
1.14
1.07
1.16
0.07
5.7
Shore D Hardness
Inner
64.8
62.7
58.9
65.2
46.6
68.6
68.2
61.2
65.4
57.0
65.2
64.6
73.3
57.7
65.6
57.4
54.1
57.3
61.88
6.26
10.1
Outer
78.6
81.4
77.0
78.9
62.7
78.1
79.2
61.3
75.7
65.7
72.2
67.4
72.1
58.7
76.0
65.8
60.9
64.9
70.92
7.48
10.5
Change %
17.5
23.0
23.5
17.4
25.7
12.2
13.9
0.1
13.6
13.3
9.7
4.1
-1.7
1.7
13.7
12.8
11.2
11.8
12.41
7.71
-
Thickness (mm)
Design
Thickness
15.0
6.0
6.0
18.0
13.5
5.0
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
6.0
6.0
6.0
N/A
-
-
-
Average
Measured
Thickness
11.9
5.7
5.9
12.5
14.2
4.7
4.8
10.7
11.0
22.2
5.6
7.1
7.3
7.1
4.7
6.6
6.7
22.8
9.52
5.55
58.3
Change %
-20.7
-4.8
-1.7
-30.6
5.2
-6.0
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
-21.7
10.0
11.6
N/A
-6.50
14.89
-
Age
(years)
21
5
25
23
23
19
19
17
17
25
19
9
23
24
34
34
34
28
-
-
-
(a) Samples received at TTC not large enough to test for this parameter.
(b) Samples received at TTC not large enough to test for this parameter but test data for the liners was received from City of Winnipeg. See also Table 4-2 in this report showing
the data from Macey et al. (2013).
-------
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Age of Liner (years)
Figure 5-1. Flexural and Tensile Moduli versus Age of Liner
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0 5 10 15 20 25 30 35 40
Age of Liner (years)
Figure 5-2. Flexural and Tensile Strengths versus Age of Liner
50
-------
1.35
1.30
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1.20
s
(S
1.15
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1.10
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Age of Liner (years)
30
35
40
Figure 5-3. Specific Gravity of Liner versus Age of Liner
5.2.7 Strength and Modulus Properties versus Specific Gravity. Figures 5-4 and 5-5 plot the
relationships between the average strength and modulus properties and the average specific gravity of
each of the liner samples. The intent is to examine whether, as might be expected, a higher specific
gravity for a sample would correlate to higher strength and modulus properties. Linear trend lines have
been added for these plots since there is a strong underlying meaning for such a relationship and each of
the data points represents the average of multiple individual tests. It can be seen by inspection of the
graph that there is an observable relationship in terms of higher strength and modulus properties with
higher specific gravities. The relationship is more noticeable in the flexural properties and particularly in
the flexural modulus than in the tensile properties but the R2 values for the trend lines still show only a
weak correlation (tensile strength 0.10, flexural strength 0.28, tensile modulus 0.44 and flexural modulus
0.46). The results indicate that the specific gravity of a sample could be a useful addition to the
parameters used to assure the quality of an installed CIPP liner. The size of sample needed for the
specific gravity evaluation is much smaller than that needed for flexural testing.
5.2.8 Relationships among the Strength and Modulus Parameters. Figures 5-6, 5-7, 5-8 and 5-
9 explore the relationships among the strength and modulus parameters measured for the 15 samples
(with data available for both parameters). It would be expected that a high quality CIPP liner or one with
an inherently stronger resin would show increases in all strength and modulus properties. Such
relationships are seen in the graphs, but to a greater or lesser extent according to the variable compared.
51
-------
In Figure 5-6, tensile modulus shows a weak correlation (R2 equal to 0.17) when compared to tensile
strength, but there is still a visible trend that as the tensile strength of a sample increases, the tensile
modulus also tends to increase.
1.00
TensStr
Flex Str
-Linear (TensStr)
-Linear (Flex Str)
1.05
1.10
1.15 1.20
Specific Gravity
1.25
1.30
1.35
Figure 5-4. Flexural Strength and Tensile Strength versus Specific Gravity
600,000
500,000
=• 400,000
VI
a.
1.00
Fmod
Tmod
-Linear (Fmod)
-Linear (Tmod)
1.05
1.10
1.15 1.20
Specific Gravity
1.25
1.30
1.35
Figure 5-5. Flexural Modulus and Tensile Modulus versus Specific Gravity
52
-------
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1,000 2,000 3,000 4,000 5,000
Tensile Strength (psi)
Figure 5-6. Tensile Modulus versus Tensile Strength
In Figure 5-7, the flexural strength values are compared to the tensile strength values. The trend in this
case is more pronounced (R2 equal to 0.46) than for the Figure 5-6 comparison and it is clearly discernible
that flexural strength tends to increase with higher tensile strength.
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1,000 2,000 3,000 4,000 5,000
Tensile Strength (psi)
Figure 5-7. Flexural Strength versus Tensile Strength
In Figure 5-8, the flexural modulus values are compared to the tensile modulus values with similar results
and a more significant correlation (R2 equal to 0.60). Perhaps the most interesting comparisons are for
the flexural and tensile strengths compared to the flexural modulus as shown in Figure 5-9. The general
increase of flexural strength with increasing flexural modulus (R2 also equal to 0.60) is much more
pronounced than for the increase of tensile strength with increasing flexural modulus (R2 equal to 0.28).
53
-------
This suggests that flexural strength or tensile modulus is better predicted from flexural modulus than is
tensile strength.
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100,000 200,000 300,000 400,000 500,000 600,000
Flexural Modulus (psi)
Figure 5-8. Tensile Modulus versus Flexural Modulus
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100,000 200,000 300,000 400,000 500,000 600,000
Flexural Modulus (psi)
Figure 5-9. Flexural Strength and Tensile Strength versus Flexural Modulus
5.2.9 Evaluations of Shore D Hardness Relationship to Other Parameters. In this section, the
possibility that surface hardness might have value as a proxy for other properties of a CIPP liner is
examined further (bearing in mind the caveats discussed in Section 5.1.9). The relationship of surface
hardness to the key liner parameter of flexural modulus is plotted in Figure 5-10, which plots the Shore D
hardness for both inner and outer liner surfaces versus the average flexural modulus measured for that
sample. All 18 samples are included in the data plotted.
54
-------
There is a significant amount of scatter in the data, particularly for the outer surface hardness results (R2
equal to 0.03 compared to 0.21 for the inner hardness). Linear trend lines have been shown in the graph,
but it should be noted that the axis for the hardness value starts at 40 rather than 0. This accentuates the
apparent relationship of hardness to flexural modulus. There is, however, an observable overall trend of
higher surface hardness with increased flexural modulus and this is physically reasonable.
• Inner • Ou
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h_*_A
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— 1
~~—*~~*m
•
100,000 200,000 300,000 400,000 500,000 600,000
Flexural Modulus (psi)
Figure 5-10. Shore D Hardness versus Flexural Modulus
Two additional figures have been developed to further explore possible relationships. Figure 5-11 plots
the surface hardness of the inner liner surface versus the age of the liner. There is large scatter (R2 equal
to 0.12) but a slight trend towards a decreasing surface hardness with increasing age. Again, it should be
noted that the vertical axis scale starts at a hardness of 40 rather than 0, which accentuates the slope of the
trend line. Figure 5-12 plots the percent change in hardness between the outer and inner surfaces (i.e.,
[outer-inner]/outer) of the liner versus the age of the liner. Here there is an even larger amount of scatter
and no observable trend.
In summary, the attraction for exploring this relationship further is that it may provide a means of
evaluation of the properties of constructed or in-service liners. Surface hardness testing would be a non-
destructive test if equipment could be developed to conduct some form of surface hardness measurement
for the inner surface of a liner in-situ. Alternatively, only a small cored sample would be necessary to
conduct meaningful surface hardness evaluations in the laboratory. These could be obtained robotically
from within the lined pipe and the damage to the in-place liner could be easily patched robotically.
Conceptually, the coupons removed to reinstate service laterals could also be used for this purpose
although the curing conditions for the liner would be locally affected by the presence of the service line.
However, in order to go further in this direction, a better understanding first needs to be established of the
typical variation of hardness through the thickness of CIPP liners and a larger database developed to study
the potential for meaningful correlations. A consistent procedure for dealing with the presence or absence
of the sealing layer would also need to be established.
55
-------
7^ n
01
(J
JS ?n n
^650
0)
"j en n
L.
0)
c cc n
M-
o c;n n
%
D
zl yic n -
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ro 4n n -
V
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+ *
•
•
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•
t •
*
0 5 10 15 20 25 30 35 40
Age of Liner (Years)
Figure 5-11. Shore D Hardness of Inner Liner Surface versus Age of Liner
01
-------
Another parameter can be constructed by comparing the specified design thickness with that measured for
the field samples in the laboratory. Lack of adherence to the specified thickness might be related to QC
issues that may have an impact on the other properties of a liner, including flexural modulus (i.e., it can
be postulated that a liner showing a deviation in thickness from that specified might have more QC issues
than a liner that meets the specified thickness). However, Figure 5-14, with the limited number of
samples that could be related to a specific design thickness, shows no relationship.
rnn nnn
cnn nnn
'«
o. /inn nnn
V)
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3
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•
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— +
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0 10.0 15.0 20.0 25.0
Hardness Change Inner to Outer Surface (%)
Figure 5-13. Flexural Modulus versus Variation in Surface Hardness
^ Flexural Modulus (psi)
e~r\r\ r\r\r\
•
c
V
nn nnn
> 4
r\r\ r\r\r\
nn nnn
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5.0 -30.0 -25.0 -20.0 -15.0 -10.0 -5.0 0.0 5.0 10.0 15.0
Thickness Variation from Specified Value (%)
Figure 5-14. Flexural Modulus versus Thickness Variation from Specified Value
57
-------
5.2.11 Summary of Results from Liner Testing at Different Ages. This section draws together
the results and observations where the same liner was tested/evaluated at different ages. Although this
may seem a more exact comparison, there may be a number of reasons why the results can differ for
reasons unrelated to aging processes. Some of the key reasons are:
• Samples collected at the time of installation are typically created outside the host pipe being
relined and the installation and curing conditions may be different from the liner within the
host pipe.
• Differences in results can occur due to spatial variability in test results rather than aging
processes.
• In one case, it was not clear whether prior testing results were for the same liner or not.
When liners are old (e.g., 23 years old), this can be difficult to establish.
Taking first the results reported in the pilot study (EPA, 2012), the following observations can be made:
• City of Denver 48 in. host pipe: This was reported to have been tested at an age of 8 years
prior to its testing under the pilot study at 23 years old. The average flexural modulus at 8
years was reported to be 490,000 ± 40,000 psi. However, it should be noted that there was a
discrepancy in that the 8-year old sample was marked as coming from an oval-shaped 48-in.
equivalent diameter brick sewer in this location, whereas the actual sewer in this location is
circular. Such discrepancies are often impossible to resolve after many years have passed
since the data was recorded. The average flexural moduli at 23 years was measured as
302,960 ± 24,303 psi (downstream of the manhole), 182,622 ± 23,126 psi and 263,707 ±
70,398 psi (two sets both upstream of the manhole) depending on the location of the sets of
samples. As noted in the pilot study report, the 2010 sample showed a high degree of
variability, especially upstream of the manhole. The similar figures for the flexural strength
are respectively: 6,900 ± 40 psi at 8 years and 7,031 ± 346 psi, 5,032 ± 652 psi and 6,117 ±
888 psi.
• City of Columbus 8 in. host pipe: The as-installed test results gave the average flexural
modulus as 464,652 ± 30,000 and the flexural strength as 7,264 ± 500. The 2010 testing (5
years old) gave the average flexural modulus as 346,050 ± 49,748 and the flexural strength as
6,416 ± 2,028. The results indicate a 5-year flexural modulus that is 25% lower than the as-
installed modulus and a flexural strength that is 12% lower. As noted above, however, this is
not a direct comparison since the as-installed sample was not cut from the actual liner
installation.
• Thames Water has published data for the first commercial CIPP installation in London (EPA,
2012). The average 20-year test results were 420,000 psi for flexural modulus and 6,700 psi
for flexural strength. The average 30-year test results were 480,000 psi for flexural modulus
and 6,200 psi for flexural strength. By these results, the flexural modulus increased and the
flexural strength decreased as the liner aged from 20 years to 30 years in service.
Moving to the current study, a few additional data/observations have been identified that directly compare
the same liner at different ages. These are:
• City of Northbrook (34-year old 12 in. diameter liner): This liner had previously been
examined through an EPA-funded study of the lining process during the period of installation
and near-term follow up (Driver and Olson, 1983). Table 5-9 shows the comparative results.
58
-------
All of the test results show a decrease over the 34 years, but it again must be stressed that a
laboratory-prepared flat plate sample is very unlikely to give the same results as a sample cut
from within a field-installed liner.
Table 5-9. Comparison of Northbrook, Illinois Retrospective Data
Parameter
Tensile Strength
Tensile Modulus
Flexural Strength
Flexural Modulus
Laboratory Flat
Plate Sample at
Time of Installation
(psi)
5,420
475,000
9,320
403,000
Field Sample Tested
After 34 Years in
Service (psi)
4,402
433,541
7,761
322,360
• Section 4 of this report examined the recent literature for other studies of CIPP liner
performance. The only study reporting test values from different ages of liners was the study
by Lystbaek (2007). The test results are shown in Table 4-6. Results are available using
retrieved samples for five liners at the ages of 8 years and 13 to 14 years. For these five
liners, three showed increases in flexural modulus and two showed decreases. Similarly, for
flexural strength, three showed increases and two showed decreases. However, the liners
showing increases for flexural modulus were not necessarily the same as for the case of
flexural strength.
In summary, while some of the comparisons show a reduction of liner mechanical properties with years in
service, these results are at times comparing different types of samples at the different ages. Focusing on
the results for which "retrieved" samples of the actual liner installation are compared and the liner
identification is secure (i.e., only the Thames Water and Lystbaek data), the results show no consistent
pattern of change with age with some results increasing by modest amounts and others decreasing by
modest amounts. These results are consistent with the graphs comparing different liners with age
(Figures 5-1 and 5-2), which do not show any clear trends.
5.3
Examples of Exploration of Relationships for CIPP Liners Using the Database
In this section, the database generated in the retrospective evaluation project and described in Section 2
will be explored to illustrate its use and to look at the variations in CIPP performance data across sites.
Only some selected plots from the database are shown here and readers are invited to visit the database
site and either download the entire database for further study or use the graphing function available
through the Web site to examine a wider variety of data comparisons and relationships.
59
-------
5.3.1 Exploring the Potential for the Database. At present, the plot parameters are restricted to
the laboratory measured test values obtained. In the future, as a larger database is available, it is intended
to broaden the range of relationships that can be explored. In Section 5.2, a number of relationships
among the test parameters were already explored using the average values from each site for comparison.
In this section, all of the individual test values are available and the data variation can be examined within
sites, as well as across sites. Although the Winnipeg test data have been reported in the average value
tables above, the Winnipeg data currently are not used for the database plotting since the flexural testing
would be the only data that was not done in the same laboratory as the remaining data. As the database is
expanded, testing from various sources across the country will be included for plotting in the database.
5.3.2 Exploration of 2-D Scatter Plot Data Relationships. Figure 5-15 shows a plot of flexural
modulus (y-axis) against tensile strength (x-axis) using a 2-D scatter plot. The user choices shown in the
select boxes are All cities CIPP, Number of Synthetic Values = 0 and Curve Fitting not Selected. The
similar trends to those already identified in Section 5.2 are seen in the plot, but with a greater number of
individual data points to better represent the full scatter in the data. Because the number of synthetic
values is chosen as zero, the number of data points plotted for each city is the least of the number of
values available for either parameter.
Trenchless Technology Center
Louisiana Tech University
xvEPA
Baltelie
f ;n c^-to, pint Tf in c™»=, DW Y M"n "°i"« n^, ] i
Select Method
j CIPP '
Select Location
Select No. of Additional Synthetic Values
Select X Axis
Tensile Strength(psi| * |
Select Y Axis
Flexural Modulus(psi) • |
Curve Fitting
138.4778.37/Retraspective/2DScatterPlot.aspx?xaxi5=tstrength psi&yaxis... 1 = ^
J 138.47
Flexural Modulus(psr)
ALL CITIES CIPP
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• COL-S-2005
» COL-16-1989
1000 20DO 3K)0 4M)C' 5000 6000
Tensile Strength(psi)
^^^d
Figure 5-15. Web Site Plot of Flexural Modulus versus Tensile Strength
In Figure 5-16, the same plot parameters (flexural modulus versus tensile strength) are used, but with the
dataset restricted to just the NYC-15-1989 (NYC Sample 2) data. This sample had one of the highest sets
of flexural modulus results and it can be seen from the plot that there is a lower variation of flexural
modulus values than for many sites making for a reduced trend in the increase in flexural modulus against
tensile strength than is seen in the overall data plot in Figure 5-15. Figure 5-17 shows the same plot as in
Figure 5-16, but with the curve fitting option selected. The linear regression trend line and 95%
confidence intervals are added to the previous graph.
60
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Trenchless Technology Center
Louisiana Tech University
Baltelle
3D ScattEf Pic! [ Msar Value; Pl-t |
Select Parameters
Select Method
CIPP »
Select Location
lNYC-15-1989 '|
Select No. of Additional Synthetic Values
fo *]
Select X Axis
Tensile Strengthipsi: *
Select V Axis
Flexural Modulus(psl) ' |
Curve Fitting
D
138.47.7
= |[5]
Q 138.47.78.37/Retrospective/2DScatterPlot.aspx?xa»s=tstrength p
NYC-15-1989
500000
450000
<~>
Vt 4CXXWQ
Flexural Modulu
**» *
* »
3000 3HD 4000 4500 5000
Tensile Strength(psi)
Figure 5-16. Web Site Plot of Flexural Modulus versus Tensile Strength for NYC-15 Sample
=% Trenchless Technology Center
Louisiana Tech University
oEPA
Umied Slat
• nvl-,)rT-
Agency
Select Parameters
Select Method
CIPP
Select Location
Select No. of Additional Synthetic Values
0 •
Select X Axis
Tensile Strengthfpsi;
Flexural Modulus(psi) *
Curve Fitting
138.47.7B.37/Retrospertive/2DScatterPlotaspx?xaxis=tstre...
138.47.78.37/Retrospective/2DScatterPloLaspx?xaxis=tstrength_
»> » »
D 95% tine Confidence
550000 -,
5DO&00
450&00-
400000-
3HXXB-
NYC-1S-1989
D 95% Poin^ Confidence
2500DD-
2DODDC'-
! 15CWO
100000-
EDCOO-
Slope 1D.47
Intercept 43B565.08
Correlation 0.14
Std Error 2&1B6.55
3500 4000 45!
Tensile Strength(psi)
Figure 5-17. Web Site Plot of Flexural Modulus versus Tensile Strength with Trend
Line for NYC-15 Sample
61
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Figure 5-18 shows a plot for all of the CIPP sites of flexural modulus versus flexural strength. Visually,
there is slightly less scatter than exhibited in the plot of flexural modulus versus tensile strength, making
for a more discernible trend.
Trenchless Technology Center
Louisiana Tech University
138.47.7837/Retrospective/2DScatterPlot.aspx?xaxis=fslrengtn_psi&yaxis.,. E
Select Parameters
Select Method
CIPP
Select Location
| ALL CITIES »|
Select No. of Additional Synthetic Values
Flexural Strength[psi'i T
Select Y Axis
Fiexural Modulusfpst! '
Curve Fitting
L 138,47.78.37/Retrospective/2DScatterPlot.asp;
-------
Select Parameters
Select Location
ALL CRIES •
Select No. of Additional Synthetic Values
Specific Gravity
Select y Axis
Flexural Modulusfpsi]
Curve Fitting
138.47.78.37/Retrospective/2DScatterPlotaspx?xaxis=density&yaxis-fmod...L
ALL CITIES CIPP
» N1C-1S-19S9
«• NYC-12-198S
» KD-42-19S6
O EDM-S-1994
O EDM-W-1994
O HOr-21-1996
O HOU-1S-1996
O NASH-S-1994
O NASH-8-2004
» NB-12-1979
» DEN-8-1984
* DEN-4S-19S7-DS
* DEN-4S-19S7-VS
* COL-8-2005
» COL-16-1989
Specific Gravity
Figure 5-19. Web Site Plot of Flexural Modulus versus Specific Gravity for All CIPP Sites
Trenchless Technology Center
Louisiana Tech University
Select Parameters
Select Method
CIPP
Select Location
Select No. of Additional Synthetic Values
100 •
' Specific Gravity
Select V Axis
Flexural Modulus(psi) '
Curve Fitting
138.47.78.37/Retrospecti«e/2DScatterPlot.aspx?xaxis=density&yaxis=fmod...L
ALL CITIES CIPP
» NYC-15-1989
« i\TC-12-19SS
* IND-42-1986
O EDM-S-1994
O EDM-10-1994
O HOr-21-1996
O HOU-1S-1996
O XASH-S-199J
<> XASH-8-2004
» XB-12-1979
» DEK-S-1984
* DEX-48-1987-US
» COL-8-200S
» COL-36-19S9
Specific Gravity
Figure 5-20. Web Site Plot of Flexural Modulus versus Density (100 Synthetic
Values) for All CIPP Sites
63
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Trenchless Technology Center
Louisiana Tech University
Figure 5-21. Web Site Plot of Flexural Modulus versus Inner Surface Hardness (No
Synthetic Values) for All CIPP Sites
Trenchless Technology Center
Louisiana Tech University
Select Paraneters
Select Method
Select Location
Select No. of Additional Synthetic Values
100 T I
Flexural Modulus[psi(
Curve Fitting
lj 138.47.78.37/Retro5pectiue/;DScalterPlot.aspx?xaxis=harrines5 inner&yaxi.J " ! ^ •&•
_: 138.47.78.37,'Retrospectiue/2DScatterPlo
» XTC-15-HS9
« NJC-12-19SS
# IND-42-19S6
O EDM-S-1994
O EDM-10-1994
O HOl~-21-1996
O HOU-1S-1996
O NASH-S-1994
O NASH-8-2004
» XB-12-1979
» DEX-S-1984
» DEN-4S-19S7-DS
» DEN-4S-1987-VS
• COL-8-200S
» COL-36-1989
Hardness(lnner)
Figure 5-22. Web Site Plot of Flexural Modulus versus Inner Surface Hardness (100
Synthetic Values) for All CIPP Sites
64
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Figures 5-23 and 5-24 examine whether the relationships appear to vary among the individual sites.
Figure 5-23 plots the data for the Indianapolis site (which has low flexural modulus values) against the
inner surface hardness. Figure 5-24 plots the data for the NYC-15 (NYC Sample 2) site, which has high
flexural modulus values. In contrast to the plots including data from all the sites, both graphs show little
trend for the flexural modulus to increase with increasing inner surface hardness.
I Trenchles* Technology Center
Louisiana Tech University
SEPA
[ -J0 !•**»!? \VJ 1 HiM.- V*h,*.»Tet 1
Select Parameters
S.l«t Method
CIPP » |
Select location
Select Ha. of Additional Synthetic Valuta
MwtXMl
Select V Axli
| Ftocural Ntoduhjupsij »|
Curve Fining
1 lB.47.7a,37/RetTosp>Ktive/2DScainefRot.aspx?xo>;is hard...
I1! 133.47.?B.37/KL-lro^'c<.livf/ilUir,J.itU'fi|l'jljip>-'x1avii=hdi
na»
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? ijft->K'
^| UOODO'
"• MOOO
4TCCP
ZKTO
*
/M
0-42-1986
* '
k *
*
t
Figure 5-23. Web Site Plot of Flexural Modulus versus Inner Surface Hardness for
Indianapolis
Trenchless Technology Center
Louisiana Tech University
Select Parameters
Select Method
NYC-15-1989 ''
Select No. of Additional Synthetic Val
Hardnessilnner)
Flexural Modulus';:-si!
Curve Fitting
500000
450000
400000-
360000'
300000
;soooo
200000
150000
* «
• ,
*.**•*
» »
• «
Hardness(lnner)
Figure 5-24. Web Site Plot of Flexural Modulus versus Inner Surface Hardness for NYC-15
65
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5.3.3 Database Mean Value Plots. The Web site provides the facility to plot bar charts of the
mean values for specific laboratory test parameters across all CIPP sites. Three examples are shown in
this section. Figure 5-25 shows the mean values of flexural modulus for all of the sites. Figure 5-26
shows the mean values of flexural strength and Figure 5-27 shows the mean values of liner specific
gravity. The interpretation of these results in terms of meeting design standards and CIPP life-cycle
performance was presented in Sections 5.1 and 5.2.
*!§=,_ .Baneiie
Seied Parameters
Mean I 'allies Bar Chan
Figure 5-25. Web Site Bar Chart for Mean Values of Flexural Modulus
I Trenchless Technology Center
Baneiie
Select Parameter
Select Parameter
il SHenflthlpslj T |
Mean I 'allies Bar Chart
I 1 I I I I i I
Figure 5-26. Web Site Bar Chart for Mean Values of Flexural Strength
66
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I Trenchless Technology Center
' Louisiana Tech University
-SEPA
Baiteiie
Select Parameters
Select Parameter
' Specific Gravity
Mean I 'allies Bar Chart
i i i i i i i i i
Figure 5-27. Web Site Bar Chart for Mean Values of Liner Specific Gravity
5.3.4 Summary for Database. In Section 5.3, a preview of the possibilities represented by the
database has been provided. Users can download both the test data and the full set of site data in a
Microsoft® Excel spreadsheet format providing users with the possibility to evaluate these datasets in
different ways and in combination with other sets of data. The database includes data for CIPP liners that
had been in the ground for up to 34 years in comparison with an original design life of 50 years. With
such a large national investment already made (and continuing) in the rehabilitation of sewers, it is
reassuring to see that the retrospective evaluation of these CIPP systems is very positive in terms of the
potential for these systems to last beyond their expected 50-year lifetime.
5.4
Other Rehabilitation Technologies
The pilot retrospective evaluation effort for trenchless rehabilitation technologies focused on CIPP
installations for gravity sewers. These were the earliest installations (other than sliplining) and CIPP has
become the dominant technology for rehabilitation. However, as the research thrust moves ahead, in
addition to finding more sites for CIPP evaluation, attention has been given to providing a retrospective
evaluation of various other trenchless rehabilitation technologies. In the current phase, these evaluations
have been restricted to technologies used in gravity sewers, but in future phases it is hoped to broaden the
retrospective evaluations to technologies used in pressure sewers and water distribution systems. In this
report, the evaluation of other rehabilitation technologies is restricted to the PVC fold-and-form liner, the
HDPE deform-reform liner and sliplining.
This section provides:
• Identification of the key test parameters used for acceptance and QC criteria in the relevant
standards for fold-and-form liners, deform-reform liners and slipliners.
• A summary of the results and their interpretation obtained from the retrospective evaluation.
67
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Description of the sample retrieval and test protocols used for the collection of fold-and-form, deform-
reform, and sliplining samples collected in the current project phase are given in Appendix A. The
detailed site information and test results for each site are given in Appendix C.
5.4.1 Sample Sites and Key Test Parameters. Table 5-10 lists the seven sites from four cities
that were used in the retrospective evaluation of PVC fold-and-form liners, HDPE deform-reform liners
and polyethylene slipliners. Two fold-and-form liners, three deform-reform liners and two slipliners were
included in the current evaluation.
5.4.1.1 PVC Fold and Form Standards. Both of the PVC fold-and-form liners evaluated are
reported to be liners provided by the company Ultraliner. The installation of these liners was covered by
ASTM Standards F1867 and F1871. The PVC liner material used in these standards should meet the
requirements of cell classification 12111 as defined in ASTM D1784. A different standard for PVC fold-
and-form rehabilitation also exists as ASTM F1504 for which materials should meet the cell
classifications 12334, 13223, 32334 or 33223 as defined in ASTM D1784. However, the retrospective
samples collected in this phase of the data collection relate to the F1867 and F1871 standards. The key
parameters for comparison with the test results are in terms of tensile strength, tensile modulus, flexural
strength and flexural modulus.
5.4.1.2 HDPEDeform-Reform Standards. The deform-reform liner materials and installation
follow the ASTM standard practice F1606 and standard specification ASTM F1533. These in turn refer
to two types of polyethylene: PE2406 (cell classification 234333[C, D or E]) and polyethylene PE3408
(cell classification 345434[C, D or E]) as defined in ASTM D3350 Standard Specification for
Polyethylene Plastics Pipe and Fittings Materials. The key parameters for comparison with the test
results are in terms of density, flexural modulus, tensile strength and environmental stress crack resistance
(ESCR). The specifications used by the City of Nashville at the time of installation specifically identify
PE3408 as the cell classification to be used for the deform-reform process and hence the retrospective
values will be compared with the values required for this classification.
5.4.1.3 Polyethylene Sliplining Standards. Polyethylene sliplining installation is covered in ASTM
F585 Standard Guide for Insertion of Flexible Polyethylene Pipe into Existing Sewers but this guide does
not specify the particular standards for the polyethylene pipe materials themselves. Hence, the most
appropriate standard with which to reference the retrospective test results is ASTM D3350 Standard
Specification for Polyethylene Plastics Pipe and Fittings Materials. Using this standard, and similarly to
the deform-reform linings, the key parameters for comparison with the test results are in terms of density,
flexural modulus, tensile strength and ESCR. The PE3408 classification is used as the reference for
comparison with the retrospective results.
5.4.2 Summary of Results for Other Rehabilitation Technologies. Table 5-10 gives the average
results for key parameters tested in the laboratory for each site for the non-CIPP retrospective samples
tested in the current study.
68
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Table 5-10. Summary of Key Laboratory Test Results for Other Rehabilitation Technologies
Location
Denver (F&F) (8 in.)
Nashville (F&F) (8 in.)
Denver (D-R) (8 in.)
Miami (D-R) (8 in.)
Nashville (D-R) (8 in.)
Houston 1 (SL) (8 in.)
Houston 2 (SL) (8 in.)
Years of
Service
15
14
15
15
19
18
Not known
Average Values
ASTM D638 (psi)
Tensile
Strength
5,418 ±547
5,914 ± 163
3,019 ±403
3,053 ± 92
2,975 ± 149
2,979 ±239
3,098 ± 542
Tensile
Modulus
288,335 ±
31,968
3 14,873 ±
36,523
145,851 ±
15,144
142,479 ±
15,584
162,567 ±
19,705
137,875 ±
81,053
147,875±
32,900
ASTM D790 (psi)
Flexural
Strength
7,791 ± 197
8,581 ±299
3,364 ± 193
3,154± 113
3,133 ±75
3,152 ± 116
3,174 ±255
Flexural
Modulus
273,471 ±
8,975
279,55 1±
8,260
108,816±
5,891
103,646 ±
4,015
108,126 ±
3,385
100,636 ±
4,728
101,881 ±
10,373
Specific
Gravity
1.32±
0.01
1.30±
0.08
0.94 ±
0.01
0.94 ±
0.01
0.94 ±
0.01
0.94 ±
0.01
0.97 ±
0.01
Shore D Hardness
Inner
63.72±
1.12
64.2 ±
1.44
55.90 ±
1.67
54.03 ±
2.69
57.56 ±
0.95
52.84 ±
1.14
53.65 ±
1.29
Outer
69.38 ±
1.50
69.72 ±
1.96
59.49 ±
1.16
56.00 ±
1.99
59.72 ±
0.98
58.15±
1.15
56.4 ±
1.73
Thickness
(mm)
4.17 ±0.05
5.21 ±0.89
7.98 ±0.25
8.33±0.11
6.85 ±0.03
7.57 ±0.09
8.45 ±0.05
F&F = fold-and-form; D-R = deform/reform; and SL = sliplining
69
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5.4.2.1 Visual Inspection. All of the fold-and-form (PVC), deform-reform (HDPE) and sliplining
(PE) samples were deemed to be in good condition.
5.4.2.2 Annular Gap. Annular gaps were measured wherever possible in the field and/or in the
laboratory. It was not always possible to measure the field values due to site configurations and/or
conditions. In addition, where the host pipe could not be retrieved from the field, annular gap
measurements were not possible in the laboratory. The available observations are summarized in Table 5-
11.
Table 5-11. Annular Gap Observations for Other Rehabilitation Technologies
Sample
Denver (F&F) (8 in.)
Nashville (F&F) (8 in.)
Denver (D-R) (8 in.)
Miami (D-R) (8 in.)
Nashville (D-R) (8 in.)
Houston 1 (SL) (8 in.)
Houston 2 (SL) (8 in.)
Annular gap observations
Varied from 0 to 2 mm with average of 0.35 mm
Varied from 0 to 6.4 mm with average of 2.83 mm
N/A
N/A
Varied from 0 to 12.7 mm with average of 5.55 mm
N/A
N/A
N/A = Annular gap could not be measured
5.4.2.3 Soil and Pipe Sediment pH Values. The pH values of any sediment inside the CIPP liner
were measured for most of the sample sites together with values from any sediment available from the
outside of the pipe. The results are tabulated in Table 5-12. The pH values for sediment retrieved from
inside the pipe varied from approximately 5 to 8.5. The pH values for the external soil samples were all
in the range of 6 to 7. Where a comparison was possible, the pH values outside the pipe tended to be
higher than inside the pipe.
Table 5-12. Measurements of pH for Other Rehabilitation Technologies
Sample
Denver (F&F) (8 in.)
Nashville (F&F) (8 in.)
Denver (D-R) (8 in.)
Miami (D-R) (8 in.)
Nashville (D-R) (8 in.)
Houston 1 (SL) (8 in.)
Houston 2 (SL) (8 in.)
Inner Pipe Sediment
PH
6 to 7
5
N/A
7 to 8
5 to 6
8 to 8. 5
7 to 8
External Soil pH
6 to 7
6 to 7
N/A
N/A
6 to 7
N/A
N/A
N/A = Sediment or soil sample not available for testing
5.4.2.4 Liner Ovality. Liner ovality was measured whenever a full circumference liner sample could
be retrieved. The measurement procedures are described in Appendix B. The ovality measurement
results are provided in Table 5-13.
70
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The maximum liner ovality measured was 2.96% for the fold-and-form samples, 6.68% for the deform-
reform samples and 3.33% for the sliplining samples. Liner ovality reduces the resistance to buckling of
an oval liner compared to an otherwise equivalent circular liner and this effect is included in the design
equations in ASTM F1216, which are also typically applied for the buckling determination of other types
of plastic liners. The ovalities for all three deform-reform samples are similar and significantly higher
than for the fold-and-form and sliplining samples. Since the ovalities were measured after the liners were
released from the host pipes, it is possible that these ovalities represented the tendency of the liner type
rather than being representative of the three host pipes from the three different cities.
Table 5-13. Measured Liner Ovality for Other Rehabilitation Technologies
Sample
Denver (F&F) (8 in.)
Nashville (F&F) (8 in.)
Denver (D-R) (8 in.)
Miami (D-R) (8 in.)
Nashville (D-R) (8 in.)
Houston 1 (SL) (8 in.)
Houston 2 (SL) (8 in.)
Liner Ovality (%)
1.66
2.96
5.20
6.65
6.68
1.76
3.33
N/A = Ovality measurement not possible because only a panel sample was available
5.4.3 Liner Thickness. The liner thicknesses for the seven sites for other rehabilitation
technologies are presented in Table 5-14. The fold-and-form liners were the thinnest at 4.2 and 5.2 mm,
respectively. The deform-reform liners ranged from 6.9 to 8.3 mm thick and the slipliners were 7.6 and
8.5 mm thick. For most of the liners, the design/specified thickness of the liner at the time of installation
could not be retrieved from the records.
All of the host pipes had a nominal 8 in. inside diameter and hence the dimension ratios are directly
comparable. The maximum dimension ratio (DR) was 48.7 for the Denver fold-and-form liner. This
value is significantly higher than the range provided in ASTM F1871. The Nashville fold-and-form liner
DR of 39 can be compared to the Nashville specifications that called for a maximum DR of 35, i.e., the
liner is slightly thinner than specified. The deform-reform liners had DRs ranging from 24.4 to 29.7. The
Nashville deform-reform liner had a DR of 29.7, which met the Nashville deform-reform specification for
a maximum DR of 32.5. The sliplining DRs were 24.0 and 26.8, but there is no specific value with which
to compare these values.
Table 5-14. Measured and Specified Liner Thickness for Other Rehabilitation Technologies
Sample
Denver (F&F) (8 in.)
Nashville (F&F) (8 in.)
Denver (D-R) (8 in.)
Miami (D-R) (8 in.)
Measured
Thickness (mm)
4.17 ±0.04
5.21 ±0.89
7.98 ±0.25
8.33±0.11
Actual
Average
DR
48.7
39.0
25.5
24.4
Cell
Class.
(ASTM)
12111
(D1784)
12111
(D1784)
PE3408
PE3408
DR Range in 8 in
Host Pipe or
Specified Minimum
Value
26-35
35
17-32.5
17-32.5
71
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Nashville (D-R) (8 in.)
Houston 1 (SL) (8 in.)
Houston 2 (SL) (8 in.)
6.85 ±0.03
7.57 ±0.09
8.45 ±0.06
29.7
26.8
24.0
PE3408
N/A
N/A
32.5
N/A
N/A
5.4.4 Specific Gravity. The specific gravity of all seven liners for the other rehabilitation
technologies was determined using ASTM D792 and the average results are listed in Table 5-10. The
standard deviations for the tests on each liner were small, indicating a good consistency of density even
after many years of service.
The average specific gravity for the PVC fold-and-form liners was in the range of 1.30 to 1.32. The
specific gravity of the PVC material is not used as a classification or specification tool in the relevant
standards and hence there is no specific reference for comparison in this application.
For the HDPE deform-reform liners, the average specific gravity was approximately 0.94. For the
polyethylene slipliners, the average specific gravity was in the range of 0.94 to 0.97. ASTM D3350
classifies polyethylene by density as low density (0.910 to 0.925), medium density (0.926 to 0.940) and
high density (0.941 to 0.965). This matches the HDPE designation for the deform-reform liners and also
indicates that the slipliners represented, in one case, a high density polyethylene and, in the other case, a
polyethylene on the border between high and medium density.
The specific gravity measurements of the liners after removal from service did not provide any evidence
of material degradation.
5.4.5 Tensile Properties. The tensile properties of the liners from the seven sites for other
rehabilitation technologies were evaluated according to ASTM D638 and are listed in Table 5-10. No test
data from the time of installation were available for any of the liner types.
The average tensile strengths for the fold-and-form liners were 5,418 psi and 5,914 psi compared to the
as-installed required tensile strength from ASTM F1867 of 3,600 psi. The average (short-term) tensile
moduli for the fold-and-form liners were 288,335 and 314,873 psi compared to the minimum required in
ASTM F1867 of 155,000 psi. Both the tensile strength and the tensile modulus values measured after 14
to 15 years of service significantly exceed the original requirements of the cell classification 12111.
The average tensile strengths for the deform-reform liners ranged from 2,975 psi to 3,053 psi compared to
the minimum permissible values at installation of 2,600 psi for PE3408. Hence, the retrospective test
values exceeded the as-installed requirement after 15 to 19 years of service. The average (short-term)
tensile moduli ranged from 142,479 psi to 162,567 psi, but there is no corresponding requirement in the
standard.
The average tensile strengths for the slipliners were 2,979 psi and 3,098 psi compared to the minimum
permissible values at installation of 2,600 psi for PE3408. The average (short-term) tensile moduli were
137,875 psi and 147,875 psi, but there is no corresponding requirement in the standard.
5.4.6 Flexural Properties. The flexural properties of the liners from the seven sites for other
rehabilitation technologies were evaluated according to ASTM D790 and are listed in Table 5-10. No test
data from the time of installation were available for any of the liner types.
The average flexural strengths for the fold-and-form liners were 7,791 psi and 8,581 psi compared to the
as-installed required flexural strength from ASTM F1867 of 4,100 psi. The average (short-term) flexural
moduli for the fold-and-form liners were 273,471 and 279,551 psi compared to the minimum required in
ASTM F1867 of 145,000 psi. Both the flexural strength and the flexural modulus after 14 to 15 years of
service are well in excess of the required values at the time of installation.
72
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The average flexural strengths for the deform-reform liners ranged from 3,133 psi to 3,364 psi, but there
is no corresponding requirement in the standard. The average (short-term) flexural moduli ranged from
103,646 psi to 108,816 psi compared to the minimum value of 80,000 psi for PE3408 and hence all the
retrospective values exceeded the as-installed requirement.
The average flexural strengths for the slipliners were 3,152 psi and 3,174 psi, but there is no
corresponding requirement in the standard. The average (short-term) flexural moduli were 100,636 psi
and 101,881 psi compared to 80,000 psi for PE3408.
5.4.7 Shore D Hardness. The Shore D hardness values for both the inner and outer surfaces of the
retrieved liner samples were determined for the seven sites for other rehabilitation technologies using
ASTM D2240 and the results are listed in Table 5-10.
The average inner hardness for the fold-and-form liners varied from 63.7 to 64.2, whereas the outer
hardness varied from 69.4 to 69.7. The average inner hardness for the deform-reform liners varied from
54.0 to 57.6, whereas the outer hardness varied from 56.0 to 59.7. The average inner hardness for the
slipliners varied from 52.8 to 53.7, whereas the outer hardness varied from 56.5 to 58.2.
As expected, the PVC liners have a higher hardness than the polyethylene deform-reform liners and
slipliners. All three types of liners have lower internal surface hardness values than external surface
hardness values after their years of service. This may be due to a slight softening of the interior surface
due to in-service exposure to the sewage flow. It would be interesting to carry out similar tests on newly
installed liners to see if there are any hardness differences caused by the reforming processes within the
host pipe.
5.4.8 Pipe Stiffness. The pipe stiffness was determined according to ASTM D2412 using three
samples for each of the seven retrospective test sites for other rehabilitation technologies. The average
values measured are listed in Table 5-15. For the PVC Type A material (Ultraliner) and for the
polyethylene materials, there are no direct pipe stiffness requirements for comparison.
Table 5-15. Pipe Stiffness for Other Rehabilitation Technologies
Sample
Denver (F&F) (8 in.)
Nashville (F&F) (8 in.)
Denver (D-R) (8 in.)
Miami (D-R) (8 in.)
Nashville (D-R) (8 in.)
Houston 1 (SL) (8 in.)
Houston 2 (SL) (8 in.)
Actual
Average
DR
48.7
39.0
25.5
24.4
29.7
24.0
26.8
Average Pipe
Stiffness
Ib/in/in
19.8
35.1
36.5
43.1
31.3
41.2
61.6
73
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CONCLUSIONS AND RECOMMENDATIONS
This section presents the overall conclusions from the retrospective study along with recommendations
for future work. Testing so far has been conducted on 18 CIPP samples from 17 separate sites across the
U.S. and Canada. These sites include both the five CIPP samples from four sites studied as part of the
pilot study (EPA, 2012) and the 13 CIPP samples tested as part of the current project. Testing also has
been conducted on seven retrospective samples from four cities for other rehabilitation technologies (PVC
fold-and-form, HDPE deform-reform and polyethylene sliplining).
6.1 Conclusions
6.1.1 Overall Observations for CIPP. The overarching conclusions from the study of the
retrospective samples of CIPP lining are as follows:
• The CIPP-lined sewers examined are holding up very well after their current in-service
exposures from 5 to 34 years. The only two ASTM F1216 mechanical strength related
quality parameters for CIPP liners are defined in terms of flexural modulus and flexural
strength. Out of the 17 retrospective sites for which data were available, only one of the
average flexural strengths was below the as-installed requirement from ASTM F1216 and, for
the flexural modulus, four of the sites had average values that were below the ASTM F1216
as-installed requirement. For the City of Winnipeg Mission St. sample, the specification at
the time of installation in 1984 only required a flexural modulus of 240,000 psi and this was
met by the retrospective sample even though it did not meet the current ASTM standard. It
also should be noted that the Denver 48 inch site had two separate samples with averages
falling above and below the 250,000 psi value but with an overall combined average above
250,000 psi. Even for the samples with low modulus values, there was no visible evidence of
distress in the liner that would indicate a progressive deterioration and it is not possible to
gauge whether the low values represent a change over time or that the original liner did not
meet the specified values.
• While some defects were noted in the samples or the associated CCTV inspections, it is
believed that most of these defects were created at the time of installation and do not
represent a degradation of the liner with time.
• In general, lining of a sewer pipe is only carried out when the existing host pipe has
experienced significant defects. For the sites studied, the CIPP lining has stabilized that
deterioration and is providing a long continued service life for the pipe. This has been
accomplished without the necessity of excavating and replacing the line from the surface.
• While the current dataset does not allow definitive conclusions to be made about the average
expected lifetime of CIPP liners, it does appear that the original design life of 50 years aimed
at by most municipalities will be met and that much longer lifetimes can be achieved.
• The above conclusions are not meant to imply that no CIPP liners will fail or have
performance issues. A number of quality/performance issues have been noted in this study
and other studies reported in the literature (see Section 4 for the review of U.S. and
international experience with CIPP linings and in particular the papers by Shelton (2012a,
2012b). These should be addressed in designs, specifications, and QA/QC procedures to
ensure that high quality liners are installed. It should also be noted that, while CIPP relining
has been shown to stabilize the deterioration of the host pipes in which it was installed and to
have a significant impact on inflow and infiltration, it does not mean that a leak-free system
74
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has been achieved unless special measures are taken to seal the liner at manholes and lateral
openings.
6.1.2 Overall Observations for the Other Rehabilitation Technologies Tested. The overarching
conclusions from the study of the other retrospective samples are as follows:
• The non-CIPP liners evaluated in this study comprised two PVC fold-and-form liners with 14
and 15 years of service, three HDPE deform-reform liners with 15 to 19 years of service, and
two polyethylene slipliners. One of the slipliners had 18 years of service and the other had an
unknown installation date, but is believed to be of a similar or older age. No historic test data
from the time of installation were available for any of these liner types.
• For the two PVC fold-and-form liners, the key parameters for evaluation are in terms of
tensile strength, tensile modulus, flexural strength and flexural modulus. Both the tensile and
flexural liner properties after 14 and 15 years of service are well in excess of the required
values at the time of installation.
• For the three HDPE deform-reform liners, the key parameters for evaluation are in terms of
density, flexural modulus, tensile strength and ESCR. The retrospective test values exceeded
the as-installed requirements after 15 to 19 years of service.
• For the two polyethylene slipliners, the key parameters for evaluation are in terms of density,
flexural modulus, tensile strength and ESCR. The installation test parameters are all satisfied
after 18 years of service for one liner and an unknown length of time for the other liner.
• The results of the other evaluation tests conducted on these liner types are provided in the
report, but did not indicate any distress or deterioration of these types of liners.
• Neither the fold-and-form nor the deform-reform liners are currently marketed in the U.S. and
sliplining is not often used in smaller diameter sewers. This reflects competitive pressures in
the marketplace and also the tendency of both the fold-and-form and deform-reform liners to
not be locked into position longitudinally after installation (causing potential misalignment of
lateral openings cut in the liner). However, in terms of the retrospective evaluation of liner
material condition, these types of liners are all performing well.
6.1.3 Some Common Threads
6.1.3.1 Lack of Historic Records for Rehabilitation Work. For a variety of reasons, many agencies
do not have full historical records for their sewer systems. This lack of information (or having erroneous
information) can be in terms of locational information, ages, materials and properties of elements of the
system and details of rehabilitation work previously undertaken. In some agencies, there may be city-
wide directives to dispose of historical data more than a certain number of years old.
These issues make it much more difficult or perhaps impossible for agencies to establish life-cycle
expectancies based on experience with various products or rehabilitation technologies within their system.
Commercial database structures are available to assemble such data in a consistent format and it is a
critical part of good asset management that agencies maintain a good dataset for future evaluation.
6.1.3.2 Quality Control in Installation. While CIPP relining has proved a fairly forgiving
technology in terms of its overall performance in the presence of local defects, the technology can
continue to benefit from improvements in QC. The New York Sample 1 example of uncured/missing
resin demonstrated the criticality of performing a comprehensive post-installation inspection of a CIPP
75
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lining project, as conditions can vary significantly along the length of the host pipe and can result in
defective regions within the newly installed liner. Some balancing trends are at work here. The
worldwide experience with CIPP installations over more than 40 years has given a strong understanding
of the materials and installation parameters that are necessary for a successful installation. However, the
change from the existence of a few large and highly experienced installers of CIPP linings to the growth
of many small installers creates the situation where the prior industry experience is not always
incorporated in projects by the less experienced installers. This is also coupled to the evolution of the
materials used within the CIPP family of techniques. While such changes were designed for the
improvement of the technology, they may introduce issues that were not present in the previous
installations.
The fold-and-form, deform-reform and sliplining technologies also present their own challenges for QC
and successful installation. Qualitative municipal experiences (see Appendix D for discussion of these
issues) indicate potential problems with the proper re-rounding of the fold-and-form and deform-reform
liners to avoid folds in the finished liner, loose liners or failure of the host pipe due to excessive internal
pressures. Slipliners are inherently installed as loose liners and hence must be grouted or anchored
longitudinally to prevent movement.
Owners and designers need to have strong QA procedures in place, checking materials used, measuring
key parameters and inspecting the key phases of the work. Contractors should make sure that they have
adequate QC procedures to deliver high quality liners that meet the specifications and will have a long
service life.
6.1.3.3 Usefulness of Various Test Parameters. One of the goals of the retrospective evaluation
program has been to investigate the most meaningful and most easily tested parameters for CIPP and
other lining types that would provide insight into a liner's quality and life expectancy. Flexural modulus
and flexural strength continue to be the most tested parameter and provide good measures for the quality
and strength of a CIPP liner. There are issues, however, with the preparation of representative samples of
the liner at the time of installation and the testing procedures themselves can allow variation in the
measured results. The specific gravity of an installed liner also is a useful measure of liner quality and
requires smaller sample sizes than for the mechanical testing. Surface hardness measurements have been
examined in this research as a potential indicator of other mechanical properties. Some degree of
correlation has been seen, but field testing protocols that would ensure removal of the sealing layer in the
area of the test would be necessary before such a test could be applied as a field testing procedure. Other
measures, not evaluated in this research but reported on by others, include permeability testing of CIPP
liners, either by laboratory testing of samples or by exfiltration testing of in-situ liners.
For the PVC and polyethylene liners, the standard material tests have demonstrated that these materials do
not tend to deteriorate noticeably under normal service conditions underground. There has not been
enough testing yet to explore the value of other test parameters for NDT or evaluation through removal of
small samples. However, the use of specific gravity and interior surface hardness may offer a similar
potential for in-service evaluations of deterioration to their use in CIPP liner systems.
76
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6.2 Recommendations
6.2.1 Future Research Needs. It is believed that the research presented in this report provides
critical information relative to the life cycle performance of relining technologies to the owners of
systems and the consultants and contractors supporting the renovation of the nation's sewerage systems.
The analysis of samples from only 18 CIPP sites plus seven other rehabilitation technology sites across
the U.S. and Canada cannot, however, provide a comprehensive answer to the questions surrounding the
performance issues that may be experienced with pipe rehabilitation technologies.
The following future research activities are recommended to build on the current work to make the
conclusions more robust and to extend this type of study to other infrastructure systems.
• Continue to collect and test samples from additional sewerage systems in North America and
especially to encourage municipalities and agencies to use opportunities where rehabilitated
sections of pipes or manholes are to be uncovered to include such collection and testing in
their work;
• Extend the range of non-CIPP rehabilitation/renewal systems that are investigated for sewer
systems;
• Apply a similar methodology to gain an understanding of the performance of rehabilitation
systems for pressure pipes, both water distribution systems and sewer force mains;
• Expand the database by adding new data as they become available and encouraging
municipalities to add their own test data to the database through administrative access
procedures with appropriate data vetting;
• Expand the qualitative assessment information from the large number of municipalities that
have experience with various forms of rehabilitation/renewal technologies. While such data
are not as precise as the retrospective sample test data, they can provide much broader
insights into the issues experienced with a rehabilitation technology and the overall level of
satisfaction with the technology; and
• Prepare guidelines for owners and consultants as to how to address the creation of reasonable
estimates of service life based on the design, installation and service parameters for
rehabilitation systems and incorporating the experience gained through the retrospective
testing program and database development.
6.2.2 Recommendations for Agencies and Municipalities. The attention to asset management
procedures in sewerage systems has grown considerably in the past decade in North America. There is
still much to be done in many agencies, however, to make sure that the right systems are in place for the
effective management of the systems and to make sure that the necessary high-quality data are collected
and preserved for the future. Many agencies are fighting a battle against an aging sewer system with
inadequate funds and personnel, but an appropriate level of understanding of system performance and
deterioration trends can allow the most effective use of limited resources.
Based upon the topics explored in this study, it is recommended that:
• Agencies treat the rehabilitation/renewal of a pipe or other element of the system as an
opportunity to build the asset management starting point for the renovated element.
• Accurate positional information and host pipe details are easily gathered while such work is
underway.
77
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The QA/QC data used to control/document the work provides the starting point for tracking
the performance of the rehabilitation/renewal technology. Such data should be maintained
within the agency's system for future comparisons.
Where feasible, agencies are encouraged to share their performance findings through the
database established in this project.
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APPENDIX A
TEST PROTOCOLS
-------
In this appendix, the testing and measurement protocols used in the retrospective data collection are
outlined for both the CIPP data collection and the data collection for the other rehabilitation technologies.
This is followed by a brief description of the ASTM standard test procedures used for the laboratory
testing.
Table A-l provides the testing and measurement protocols for field-based measurements and Table A-2
for laboratory-based measurements for the CIPP retrospective evaluations. The parameters to be
measured included visual inspection, annular gap, liner thickness, specific gravity, tensile
strength/modulus, flexural strength/modulus, surface hardness, glass transition temperature, and porosity.
The testing parameters also depended on the size of the sample retrieved and are defined as noted below
for small and large diameter liner samples. For example, ovality and buckling tests were only applicable
to whole pipe samples collected from small diameter pipes. In some cases, due to the sample retrieval
process, the site conditions or the host pipe/liner condition, it was not possible to collect all of the data for
all of the samples. The specific information collected for each sample is provided with the discussion for
each test location in Appendix B.
A-l
-------
Table A-l. Protocol for CIPP Field Measurements and Retrieved Samples
Field Measurements
No. of
Measurements
Sample
Test Standard/
Instrument
Notes
Large Diameter Sewer
Liner only specimen
Visual liner inspection
Liner thickness
(Retrieved Sample)
Annular gap
(Remaining Host Pipe)
1
Continuous
4
8
24 in. x 24 in.
N/A
N/A
N/A
N/A
N/A
Caliper
Feeler gauge
Shipped to TTC
Digital photos
1 measurement on
each side of the
removed CIPP panel
(to nearest mm).
2 measurements on
each side of existing
CIPP liner at
removed section.
Note measurements
to be conducted by
City contractor after
sample removal.
Small Diameter Sewer
Liner + host pipe
specimen
Visual liner inspection
Soil conditions +
bedding
Liner thickness
(Remaining Host Pipe
and Retrieved Sample)
Annular gap
(Remaining Host Pipe
and Retrieved Sample)
1
Continuous
6
8 x 2 = 16 for
remaining host
pipe
8 x 2 = 16 for
retrieved sample
8 x 2 = 16 for
remaining host
pipe
8 x 2 = 16 for
retrieved sample
6 ft length
N/A
Grab samples
N/A
N/A
N/A
N/A
N/A
Caliper
Feeler gauge
Shipped to TTC
Digital photos
Soil lab analysis and
visual inspection.
8 measurements at
45° each side (north
and south) of host
pipe and removed
section.
8 measurements at
45° each side (north
and south) of host
pipe and removed
section.
N/A = not applicable
A-2
-------
Table A-2. Protocol for CIPP Laboratory Measurements
Laboratory
Measurements
Visual Liner
Inspection
Apparent Specific
Gravity/Density
Tensile Strength
and Elongation at
Failure
Tensile Strength
and Elongation at
Failure
Flexural Strength
and Flexural
Modulus
Flexural Strength
and Flexural
Modulus
Duro meter (Shore)
Hardness
Glass Transition
Temperature
Porosity
Pipe Ovality
Short-Term Liner
Buckling Strength
Soil Analysis
Samples
All samples
All samples
Small Diameter
Large Diameter
Small Diameter
Large Diameter
All samples
All samples
All samples
Small Diameter
Small Diameter
Small Diameter
No. of
Measurements
(each site)
Continuous
3 each
3
3
5
5
5 each
2 each
1
1
1
6
Sample
Size
N/A
2 in. x 2
in.
0.75 in. x
7.2 in.
each
1.13 in. x
9.7 in.
each
1 in. x 5
ft each
2 in. x 12
in. each
N/A
3 in. x
0.5 in.
N/A
1ft
4ft
sample
length
500 g
Test Standard/
Instrument
N/A
ASTMD792
ASTMD638
ASTMD638
ASTM D790
ASTM D790
ASTM D2240
ASTME1356
Differential
Scanning
Calorimetry
Mercury vapor
intrusion test
Profile plotter
ASTMF1216
ASTM C136 sieve
analysis; ASTM
C128 density;
ASTMD2216
moisture content;
and Thermo Orion
meter for soil pH
Notes
Surface film,
leakage,
corrosion,
bacterial
growth, etc.
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Measurements
continuous in
buckling test
sample
Modified
according to
sample
condition
N/A
N/A = not applicable
A-3
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For the other rehabilitation technologies, the sample field collection protocol was similar to that
previously used for CIPP. A pipe length of 6 to 8 ft was retrieved including the liner and host pipe.
Table A-3 summarizes the information to be collected in the field.
Table A-3. Protocol for Field Measurements and Retrieved Samples for Other Rehabilitation
Technologies
Field Measurements
Liner + host pipe
specimen
Visual liner inspection
Liner thickness
(Remaining Host Pipe
and Retrieved Sample)
Annular gap
(if applicable)
(Remaining Host Pipe
and Retrieved Sample)
Grout thickness
(if applicable)
(Remaining Host Pipe
and Retrieved Sample)
No. of
Measurements
1
Continuous
8x2= 16 for
remaining host
pipe
8 x 2=16 for
retrieved sample
8 x 2= 16 for
remaining host
pipe
8 x 2=16 for
retrieved sample
8 x 2= 16 for
remaining host
pipe
8 x 2=16 for
retrieved sample
Sample
6 to 8 ft(a)
N/A
N/A
N/A
N/A
Test Standard/
Instrument
N/A
N/A
Caliper
Feeler gauge
Caliper
Notes
Shipped to TTC
CCTV or digital photos.
Verify that the liner is tight
at the ends and at any
reinstated laterals.
Document any evidence of
holes, splitting, cracking, or
breaking. Note any
localized areas indicating
uneven stretching. Verify
that the reinstated laterals
are fully opened.
8 measurements at 45° each
side (north and south) of
host pipe and removed
section.
8 measurements at 45° each
side (north and south) of
host pipe and removed
section.
8 measurements at 45° each
side (north and south) of
host pipe and removed
section.
N/A: not applicable
(^Depending on material and presence of pipe joints, laterals or bends
The laboratory analyses were established according to the type of liner sample. Tables A-4 to A-6
summarize the laboratory analyses employed to test the samples for fold-and-form (using polyvinyl
chloride [PVC]), deform/reform (using polyethylene [PE]), and sliplining [using PVC or PE]).
A-4
-------
Table A-4. Laboratory Measurements for Fold-and-Form Samples (PVC)
Laboratory
Measurements
Visual Inspection
Pipe Inside
Diameter
Pipe Outside
Diameter
Wall Thickness
Pipe Ovality
Tensile Strength
and Elongation at
Failure
Flexural Strength
and Flexural
Modulus
Pipe Stiffness
Density
Samples
N/A
1
1
1
1
6
6
3
6
No. of
Measurements
(each site)
1
16
16
16
3
6
6
3
6
Sample
Size
6 to 8 ft
18 in.
18 in.
18 in.
6 to 8 ft
6 in. long
X
1 in. wide
6 in. long
X
1 in. wide
6 in.
1 in. x l in.
Coupon
Test Standard/
Instrument
Any evidence of holes,
splitting, cracking, or
breaking.
ASTMD2122
ASTMD2122
ASTMD2122
Profile plotter
ASTMD638
ASTMD790
ASTMD2412
ASTMD792
N/A: not applicable
A-5
-------
Table A-5. Laboratory Measurements for Deform/Reform Samples (PE)
Laboratory
Measurements
Visual Inspection
Pipe Inside Diameter
Pipe Outside Diameter
Wall Thickness
Pipe Ovality
Tensile Strength and
Elongation at Failure
Flexural Strength and
Flexural Modulus
Pipe Stiffness
Density
Hardness
Environmental Stress
Cracking (ESCR)
Samples
N/A
1
1
1
1
6
6
3
6
6
6
No of
Measurements
(each site)
1
16
16
16
3
6
6
3
6
20
6
Sample Size
6 to 8 ft
18 in.
18 in.
18 in.
6 to 8 ft
X
1 in. wide
6 in. long
X
1 in. wide
6 in.
1 in. x l in.
Coupon
1 in. x l in.
Coupon
6 in. long
X
2 in. wide
Test Standard/
Instrument
Any evidence of holes,
splitting, cracking, or
breaking.
ASTMD2122
ASTMD2122
ASTMD2122
Profile plotter
ASTMD638
ASTM D790
ASTMD2412
ASTMD792
ASTMD2240
ASTM D 1693
N/A: not applicable
Table A-6. Laboratory Measurements for Sliplining (PVC or PE)
Laboratory
Measurements
Visual Inspection
Pipe Inside
Diameter
Pipe Outside
Diameter
Wall Thickness
Pipe Ovality
Tensile Strength
and Elongation at
Failure
Flexural Strength
and Flexural
Modulus
Pipe Stiffness
Density
Hardness
Samples
N/A
1
1
1
1
6
6
3
6
6
No. of
Measurements
(each site)
1
16
16
16
3
6
6
3
6
20
Sample Size
6 to 8 ft
18 in.
18 in.
18 in.
6 to 8 ft
6 in. long
X
1 in. wide
6 in. long
X
1 in. wide
6 in.
1 in. x l in.
Coupon
1 in. x l in.
Coupon
Test Standard/
Instrument
Any evidence of holes,
splitting, cracking, or
breaking.
ASTM D2 122
ASTM D2 122
ASTM D2 122
Profile plotter
ASTMD638
ASTMD790
ASTMD2412
ASTMD792
ASTMD2240
N/A: not applicable
A-6
-------
The main sample test data included are thickness (ASTM D2122), flexural modulus and flexural strength
(ASTM D790), tensile modulus and tensile strength (ASTM D638), apparent specific gravity (ASTM
D792), and hardness (ASTM D2240). The procedures for the collection of the main sample test data are
provided below.
Sample Thickness Measurement. In ASTM D2122, specimens were cut into 1 in. x 1 in. squares and the
thickness was measured using a micrometer with a resolution of ±0.0025 mm (see Figure A-l).
Figure A-l. Micrometer Set (left) and Measurement of Thickness Using a
Micrometer (right)
Flexure and Tensile Testing. Flexure (ASTM D790) and tensile (ASTM D638) tests were performed
using a 2.2 Kip capacity universal testing machine. No slippage was ensured by employing the pneumatic
grips during the tensile test. The samples were prepared according to the relevant standard (see Figure A-
2) and later tested using the universal testing machine (see Figure A-3). It should be noted that, for the
tensile testing, the extensometer used had a range of up to 2 in. elongation and hence the tensile tests were
stopped if the specimen extension reached this value.
t •
Figure A-2. ASTM D638 Specimens (left) and ASTM D790 Specimens (right)
A-7
-------
Figure A-3. ASTM D638 Test (left) and ASTM D790 Test (right)
Apparent Specific Gravity. Apparent specific gravity was measured following ASTM D792. Specimens
of 1 in. x 1 in. size were cut from the CIPP liner/panel. The weight of each specimen was measured first
in air and later in water. A sinker was used to ensure submersion of the test sample (see Figure A-4). The
water temperature also was read to allow the appropriate water density to be used.
Figure A-4. Weight Measured in Air (left) and in Water (right)
Durometer (Shore Type D) Hardness. Durometer (Shore Type D) hardness (ASTM D2240) was used to
determine the hardness of the liner samples (see Figure A-5). Samples (1 in. x 1 in.) were cut from the
retrieved CIPP liner with a band saw. The Shore D hardness scale utilizes a weight of 10 Ib (4,536 g).
The tip diameter and angle are 0.1 mm and 35°, respectively. Readings were taken on the inner and outer
surfaces of the liner specimens.
A-8
-------
Figure A-5. Hardness Test Instrument (left) and Hardness Test on a Specimen (right)
A-9
-------
APPENDIX B
CIPP CASE STUDIES
-------
The recovery and testing of the retrospective samples collected in this phase of the research are presented
in this appendix. A total of 14 samples from seven different wastewater collection systems were collected
for the CIPP portion of the retrospective study and 13 of these samples were tested according to the test
protocols established (one of the New York samples had a major defect that precluded detailed testing).
The municipalities/entities providing samples included the following: Edmonton, Canada; Houston,
Texas; Indianapolis, Indiana; Nashville, Tennessee; New York, New York; Northbrook, Illinois; and
Winnipeg, Canada. The testing protocols are similar from one case study to the next and the standard
laboratory testing procedures for the key material properties were described and illustrated in Appendix
A. Additional test protocols (e.g., buckling tests) are described in this appendix with photographs of the
associated procedures and test setup when they first appear but are not repeated for the subsequent case
studies. The case studies are presented below in alphabetical order.
This appendix describes the data collection, analyses, and project documentation in accordance with EPA
NRMRL's QAPP Requirements for Applied Research Projects (EPA, 2008) and the project-specific
QAPPs (Battelle, 2012a; 2012b; and 2013). A QA review was performed on the CIPP case study data
presented in Appendix B. All of the results met the QC objective for completeness. Completeness refers
to the percentage of valid data received from the testing laboratory. A few results for flexural
strength/modulus (3.1%) and for tensile strength/modulus (3.8%) were outside of the QC criteria for
relative percent difference (RPD) of + 25%. However, this could be attributable to variations within the
material properties of the field-installed CIPP product itself. These data were retained for study purposes,
but are noted in the tables below.
B.I City of Edmonton
B.I.I Introduction. This report contains the test results performed on two liners exhumed from
119 St., south of 111 Ave., Edmonton, Alberta, Canada. Two samples were collected with inside host
pipe diameters of 10 in. and 8 in. (250 mm and 200 mm).
B.1.2 Edmonton Sample 1: A 19-Year Old CIPP Liner in a 10 in. (250 mm) Non-reinforced
Concrete Pipe. Edmonton Sample 1 was retrieved from 119 St. and 109A Ave. in Edmonton, Canada on
June 21, 2013. The host pipe and liner information are shown in Table B-l. The exposure of the liner
due to operating conditions within the sewer was considered relatively benign. The host pipe was at a
depth of approximately 3 m (9.8 ft) below ground level.
Table B-l. Edmonton 1: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Non-reinforced concrete pipe,
10 in. (250 mm) in diameter
4.81 mm @ 10:00 and 4.92 mm @ 1:00 (design thickness of 5
mm)
Information not available
Information not available
Information not available
Information not available
Polyurea was used for internal
coating
November 1994
Insituform Technologies
Camtron or Ashland
B-l
-------
The retrieval process and the retrieved sample are shown in Figure B-l. The specimens were received at
the TTC South Campus Lab Facility on July 23, 2013.
B. 1.2.1 Visual Inspection. The sample was found to be in excellent condition. The polyurea coating
was still present and the thickness was uniform around the circumference.
Figure B-l. Edmonton 1: Retrieval of the Sample (left) and Received Sample (right)
B.l.2.2 Annular Gap. The annular gap was measured using a feeler gauge at the ends of the host
pipe/liner that remained in the ground. At the north end of the sample, recorded as "Remaining Host Pipe
(North)", the initial measurement was recorded in the trench box where the lower half of the pipe was not
accessible. Only a 0.036 in. gap was measured at the 10 o'clock position and a 0.011 in. gap was
measured at the 2 o'clock position. The remaining locations above the spring line of the liner were found
to be fairly tight. Eight readings also were taken at the other end of the sample, recorded as "Remaining
Host Pipe (South)". Both sets of readings are shown in Table B-2.
Table B-2. Edmonton 1: Field Readings of Annular Space with Feeler Gauge
O'Clock Position
12:00
1:30
2:00
3:00
5:00
6:00
7:30
9:00
10:00
11:00
Annular Gap Measured for
Remaining Host Pipe
(north end of sample)
Tight
Tight
0.011 in. (0.28mm)
Tight
N/A
N/A
N/A
Tight
0.036 in. (0.91mm)
Tight
Annular Gap Measured for
Remaining Host Pipe
(south end of sample)
0.014 in. (0.40mm)
0.014 in. (0.40mm)
N/A
0.024 in. (0.61mm)
0.025 in. (0.63 mm)
0.0 11 in. (0.28mm)
0.013 in. (0.33 mm)
0.0 18 in. (0.46mm)
N/A
0.25 .(0.63mm)
B.l.2.3 Environmental Service Conditions. 2 g of waste material was scooped from the inside
surface of the sample and mixed in 200 mL of distilled water stored in a bottle; pH was measured using a
B-2
-------
pH-indicator strip (see Figure B-2). The pH was found to be between 7 and 8. No material could be
collected from the outer side of the liner for comparison.
Figure B-2. Waste Material Collected from Sample (left) and Measurement of pH
using a pH-Indicator Strip (right)
B. 1.2.4 Ovality. A profile plotter was used to accurately map any deformation inside the liner (see
Figure B-3 for the setup that was used for the Edmonton 8 in. [200 mm] liner). The system features a
linear variable displacement transducer (LVDT) connected to a motor-gear system that rotates around the
inner circumference of the liner. An encoder system provides position information regarding the location
around the pipe at which the data are taken.
The liner was placed on a wooden saddle, clamped with the platform, and careful measurements were
taken to ensure that the liner center was aligned with the measuring device. Next, the profile plotter was
aligned with the center of the CIPP liner tube. Continuous readings were taken around the circumference
of three cross-sections spaced 8 in. apart and averaged. The liner was found to be approximately circular
with reference to its center (see Figure B-4). The ovality of the liner was found to vary from 2.70% to
4.30%.
Figure B-3. Profile Plotter Setup (left) and Ovality Measurement (right)
B-3
-------
Profile Plot - 250mm Liner
-10 in Reference Line
-Middle Section
-Up Stream
-Down Stream
Figure B-4. Edmonton 1: Ovality of the Liner at Up Stream,
Middle and Down Stream Sections
B. 1.2.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the liner specimen. The thickness was measured randomly using a micrometer with a
resolution of ± 0.0025 mm as described in Section 2. The average thickness was found to be 4.66 mm ±
0.21 mm as shown in Figure B-5. The design thickness was 5 mm.
Edmonton 250mm
•• Average 5.00mm
m,— Average 4.66mm ±0.21 mm
'iiimniiiiii
m T in
• II
58 59 510 511 512 513 514 515 516 S17 518 519 520
51 52 S3 54 55 56
Measured specimens
Figure B-5. Edmonton 1: Thickness of the Sample
B-4
-------
B. 1.2.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples in
accordance with the ASTM D792 standard. The weight of the sample was measured in air and in water.
The water temperature was read at 77°F. A sinker was used to ensure submersion of the test sample.
The specific gravity values from the sample are shown in Figure B-6. The obtained values were between
1.16 and 1.27. The average specific gravity was 1.25.
Edmonton 250mm
Weighted average 1.25 ± 0.02
S "*
1.40 r- f\ — i — ;
1.30 [- " — *i—ri":
1.20
1.10
.rt.
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure B-6. Edmonton 1: Measured Specific Gravity
B. 1.2.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
liner using a table saw and a band saw. The Type II specimen dimension was used for the ASTM D638
tensile test. The sides of the specimens were smoothed using a grinder. A total of 15 specimens were
prepared and tested. Marked tensile specimens and the test setup are shown in Figures B-7 and B-8.
Figure B-7. Five Specimens (left) and 10 More Specimens (right)
Prepared for Tensile Testing
B-5
-------
Figure B-8. Tensile Testing in Accordance with ASTM D638 (left) and
Samples after Test (right)
The tensile test results are presented in Figure B-9 and Table B-3. The average tensile strength was 3,241
±214 psi. The average tensile modulus was calculated to be 436,709 ± 68,229 psi.
Tensile Modulus of Elasticity
4000
0.1
0.12
Figure B-9. Edmonton 1: Stress-strain Curves from Tensile Testing
B-6
-------
Table B-3. Edmonton 1: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0845
0.0820
0.0822
0.0825
0.0848
0.0829
0.0836
0.0948
0.1000
0.0968
0.0911
0.0827
0.0846
0.0867
0.0765
Peak Load
(Ib)
283.30
251.10
239.91
258.64
266.31
291.15
292.03
306.27
302.22
336.12
287.51
269.16
253.35
316.16
246.86
280.01
28.02
Peak Stress
(psi)
3,353
3,062
2,919
3,135
3,140
3,512
3,493
3,231
3,022
3,472
3,156
3,255
2,995
3,647
3,227
3,241
214
Tensile
Modulus
(psi)
580,343*
369,959
425,821
529,530
497,291
483,457
446,496
424,398
304,417*
425,937
409,601
457,080
402,287
429,778
364,254
436,709
68,229
*Result is not within ± 25% RPD.
B.l.2.8 Flexural Test (ASTMD790). A total of 15 specimens were prepared for ASTM D790
flexure tests. The prepared specimens and test setup are shown in Figures B-10 and B-l 1.
Figure B-10. Five Specimens (left) and 10 More Specimens (right)
for Flexural Testing
B-7
-------
Figure B-ll. Flexural Testing in Accordance with ASTM D790 (left) and
Samples after Test (right)
The flexure test results are presented in Figure B-12 and Table B-4. The area values were automatically
back calculated by the software when the peak load was reached. The average flexural modulus was
331,333 ± 30,354 psi and the average flexure strength was 6,135 ± 535 psi.
Flexural Stress Vs Flexural Strain
I
I
- Sample 1
- SarnpEeZ
— Sample
- Sampled
- Sample G
- Sample 7
— Sample H
- Sample 9
- Sample 10
- Sample 11
Sample
Sample
Sample 14
Sample 15
Flexural Strain, in/in
Figure B-12. Edmonton 1: Stress - Strain Curves from Flexural Testing
B-8
-------
Table B-4. Edmonton 1: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0028
0.0031
0.0030
0.0031
0.0031
0.0031
0.0034
0.0034
0.0034
0.0031
0.0033
0.0034
0.0034
0.0035
0.0030
Peak Load
(Ib)
16.60
14.72
19.27
17.41
18.57
20.04
22.01
20.94
23.61
19.48
20.52
18.90
23.01
21.53
18.89
19.70
2.39
Peak Stress
(psi)
5,929
4,748
6,423
5,616
5,990
6,465
6,474
6,159
6,944
6,284
6,218
5,559
6,768
6,151
6,297
6,135
535
Flexural
Modulus
(psi)
322,781
284,443
314,699
282,367
300,724
323,089
357,066
350,483
392,559
348,759
356,834
304,633
348,563
341,379
341,617
331,333
30,354
B. 1.2.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. The Shore D hardness scale utilizes a weight of 10 Ib (4,536 g). The tip
diameter and angle are 0.1 mm and 35°, respectively. Samples (1 in. x 1 in.) were cut from the retrieved
CIPP liner with a band saw. A total of 400 readings were taken on the inner and outer surfaces of the
liner specimens. The average recorded hardness values are shown in Figure B-13. The hardness of the
surface exposed to the flow (inner surface) was found to be only slightly lower than that of the protected
(outer) surface, suggesting little, if any, softening or erosion of the resin on the inner surface of the tube
during its service life. Differences may also be expected due to the initial presence of the sealing layer on
the internal surface.
B. 1.2.10 Short-Term Buckling Test. For the short-term buckling test, a 30 in. long piece of full
circumference was cut from the sample and housed inside a 12-in. diameter steel tube 30 in. in length.
The larger diameter of the steel tube ensured accommodation of any ovality and local curvature of the
liner. Two 3/8 in. threaded holes were made on the opposite sides of the steel tube and quick connectors
were fixed to the pipe through the holes to allow attachment of the pressure system. Two specially
designed, open-ended steel caps were fabricated to keep a uniform 1-in. annular space between the inner
wall of the pipe and the outer wall of the liner and these end caps were then sealed. Effective sealing of
the annulus under elevated internal annular pressure was essential during the test while the interior of the
liner was frequently accessed for observation of liner deformation. The large annular gap for the buckling
test makes the buckling test very conservative compared to a liner tightly fitted within the host pipe in the
field. However, the test sections also are known to be too short to eliminate end effects (not conservative)
because the host pipe configuration and overall testing program did not permit a pipe section with a
length of four to six times diameter (32 to 48 in.) to be used.
B-9
-------
Edmonton 250mm DINNER BOUTER
Weighted average of inner surface 68.6 ± 0.2
Weighted average of outer surface 78.1 ± 0.7
60
45
30
tri K i^-ov KK K«-i ID 00" ior-
i£>!r-j oo uir-
» vDrr*- r*- oo or
• tDP^j vD 00 >kO:h«-
rH
t-^
S|P vor
{ S
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Specimen
Figure B-13. Edmonton 1: Shore D Hardness Readings from Inner and Outer Surfaces
Provision was made to apply a high pressure using the TTC's elevated pressure application device
(EPAD). First, the test specimen was connected to the EPAD and the EPAD was connected to the water
supply line. The annular space between the liner and host pipe plus all the conduits and the accumulator
were filled with water. This was ensured by bleeding the air out through the quick connector attached to
the steel tube. The accumulator was connected to an N2 tank and, when pressurized, N2 was released to
the accumulator where it compressed the water inside the accumulator, exerting pressure on the annular
space.
The liner collapsed under the supply line water pressure at around 12 psi before the N2 was released to the
accumulator (see Figure B-14). This is equivalent to over 27 ft of water head above the pipe.
Figure B-14. Edmonton 1: Short-Term Buckling Test Setup
B. 1.2.11 Glass Transition Temperature. Differential scanning calorimetry (DSC) is used to perform
thermal characterization studies on thermosetting resins. As the components in a resin system cure, heat
is evolved and measured by the DSC. When no significant heat of cure is observed, then it is assumed
B-10
-------
that the resin sample is completely or 100% cured. DSC can also be used to measure the glass transition
temperature (Tg) or softening temperature of a thermoset resin. Tg represents the temperature region in
which the resin transforms from a hard, glassy solid to a viscous liquid. As a thermosetting resin cures,
the Tg increases and the heat of cure decreases. These changes can be used to characterize and quantify
the degree of cure of the resin system (Perkin-Elmer, 2000).
The Tg determination followed ASTM E1356-08 "Standard Test Method for Assignment of the Glass
Transition Temperatures by Differential Scanning Calorimetry." The calculated Tg values are
summarized in Table B-5 for the Edmonton 250 mm CIPP sample. The average Tg for the field samples
was 115.48°C (+/- 0.91°C) as measured by ASTM Method E1356-08 with DSC. In general, an increase
in the Tg is a function of curing and represents the increase in the molecular weight of the resin system
(Perkin-Elmer, 2000).
Table B-5. Edmonton 1: Tg Determination (250 mm CIPP Liner)
Sample
Edmonton (250 mm)
Edmonton (250 mm)
Edmonton (250 mm)
Run
1
2
3
Tg (°C)
115.82
116.17
114.45
B.1.3 Edmonton Sample 2: A 19-Year Old CIPP Liner in an 8 in. (200 mm) Clay Tile Pipe.
Edmonton Sample 2 was retrieved from 119 St. and 109A Ave. in Edmonton, Canada on June 21, 2013.
The liner had been installed in 1994 by Insituform Technologies. The clay tile host pipe had originally
been installed in 1955. The location was a sag location and therefore was always filled with wastewater
to at least 80%. The exposure was considered severe in terms of possible H2S generation. Significant
difficulties were encountered in recovering the CIPP liner. The city had to call for a vacuum truck to
empty the line and used jetting equipment to flush the line and remove a downstream blockage that
hindered flow and prevented the pipe from draining. Thus, measurement of annular space or pipe
thickness was not possible for the remaining host pipe due to the challenging working conditions.
However, these measurements were made from the exhumed CIPP and host pipe sample. The host pipe
and liner information are shown in Table B-6. The host pipe was at a depth of approximately 3.1m (10.2
ft) below ground level.
Table B-6. Edmonton 2: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Clay tile pipe, 8 in. (200 mm) in
diameter
4.76 mm (laboratory measurement)
Information not available
Information not available
Information not available
Information not available
Information not available
1994
Insituform Technologies
Camtron or Ashland
B-ll
-------
The retrieval process and the retrieved sample are shown in Figure B-15. The sample was received at the
TTC South Campus Facility on July 23, 2013.
Figure B-15. Edmonton 2: Retrieval of the Sample (left) and Received Sample (right)
B. 1.3.1 Visual Inspection. The sample was found to be in excellent condition. The polyurea coating
(handling layer) was still in place and the thickness of the liner was uniform around the circumference.
B. 1.3.2 Annular Gap. The annular gap was measured using a feeler gauge on the exposed ends of
the exhumed sample, which were marked as downstream and upstream, respectively. For the downstream
end, the liner was found to be tight to the host pipe and no gap was observed. For the upstream end, eight
readings were taken on the liner as shown in Table B-7.
Table B-7. Edmonton 2: Field Readings of Annular Gap Using a Feeler Gauge
O' Clock
Position
12:00
1:30
3:00
5:00
6:00
7:30
9:00
11:00
Annular Gap at Downstream
End of Sample
Tight
Tight
Tight
Tight
Tight
Tight
Tight
Tight
Annular Gap at Upstream End
of Sample
0.078 in. (1.98mm)
0.031 in. (0.79mm)
0.00 in. (0.00 mm)
0.031 in. (0.79mm)
0.00 in. (0.00 mm)
0.031 in. (0.79mm)
0.031 in. (0.79mm)
0.46 .(1.17mm)
B.l.3.3 Environmental Service Conditions. 2 g of waste material was scooped from the outside
surface of the sample and mixed in 200 mL of distilled water stored in a bottle. The pH of the water was
measured using pH-indicator strips and found to be between 8 and 9. The inside of the liner was found to
be clean and hence no material was collected to allow a pH measurement.
B-12
-------
B.l.3.4 Ovality. A profile plotter (see Figure B-16) was used to map any deformation inside the
liner. The system features a LVDT connected to a motor-gear system that rotates around the inner
circumference of the liner. An encoder system provides position information regarding the location
around the pipe at which the data are collected.
Figure B-16. Edmonton 2: Profile Plotter Setup (left) and Measurement of Ovality (right)
The liner was placed on a wooden saddle, clamped with the platform, and careful measurements were
taken to ensure that the liner center was aligned with the measuring device. Next, the profile plotter was
aligned with the center of the CIPP liner tube. Continuous readings were taken around the circumference
of three cross-sections spaced 12 in. apart and averaged. The liner was found to be approximately
circular with reference to its center (see Figure B-17). The ovality of the liner was found to vary from
4.50% to 5.75%.
Profile Plot (200mm)
-Host-Pipe —Upstream
Middle Section —Downstream
Figure B-17. Edmonton 2: Ovality of the Liner Measured at Three Locations
B-13
-------
B. 1.3.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
± 0.0025 mm. The average thickness was found to be 4.76 mm ± 0.21 mm as shown in Figure B-18. The
design thickness was not available.
Edmonton 200mm
5.2
5.0
4.8
'. 4.6
1
t
J
j 4.4
4.2
4.0
3.8
Average 4.76mm ± 0.21 mm
II imiiiim
SI S2 S3 S4 S5 S6 57 S8 S9 S10 Sll S12 513 514 515 516 517 518 519 S20
Measured specimens
Figure B-18. Edmonton 2: Average Thickness of the Sample
B. 1.3.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with the ASTM D792 standard. The test procedure was the same as for the 250 mm sample
test.
The specific gravity values from the sample are shown in Figure B-19. The obtained values were
between 1.12 and 1.33. The average specific gravity was 1.25.
Edmonton 200mm
Wpishtprl a»pr»Re l.J1; * 0.00?
1.20
n
& f'-Wl
(t.S(]
0.40
0.30
0.20
0.10
0.00
0
f
.,.
i 1
] I
'1 I
•| r
s I
S '
; i
1 ;
: -
J <•
s
•• f
, ?
1
i T
;
, I
i .
\ 1
1 *
! s
I
:
I
i
•
J s
I '
I f^
; 5
; a
S 9 10 11 12 13 14 K 1C 17 18 19 20
Number of Samples
Figure B-19. Edmonton 2: ASTM D792 Measured Specific Gravity
B-14
-------
B. 1.3.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
liner using a table saw and a band saw. The Type II specimen dimension was used for the ASTM D638
tensile test. The sides of the specimens were smoothed using a grinder. A total of 15 specimens were
prepared and tested. The tensile test results are presented in Figure B-20 and Table B-8. The average
tensile strength was 3,652 ± 283 psi and the average tensile modulus was 510,132 ± 44,227 psi.
Tensile Modulus of Elasticity
4500
Sample1?
Sample 10
Sample 11
Sample 13
Stimuli.' U
Sample 14
Sample IS
Figure B-20. Edmonton 2: Stress - Strain Curves from Tensile Testing
Table B-8. Edmonton 2: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.097
0.092
0.087
0.091
0.097
0.083
0.088
0.094
0.085
0.087
0.085
0.085
0.093
0.086
0.090
Peak Load
Ob)
299.64
330.04
296.84
336.83
332.25
346.02
302.73
341.92
346.22
322.74
330.32
326.07
337.42
325.50
301.58
325.07
17.04
Peak Stress
(psi)
3,095
3,603
3,412
3,693
3,443
4,179
3,432
3,637
4,054
3,735
3,895
3,850
3,648
3,772
3,340
3,653
283
Tensile
Modulus
(psi)
452,964
517,501
489,893
494,339
496,788
587,463
485,838
503,237
562,930
575,307
517,573
488,958
502,801
551,644
424,749
510,132
44,227
B-15
-------
B.l.3.8 Flexural Test (ASTMD790). A total of 15 specimens were prepared for the ASTM D790
flexure tests. The flexure test results are presented in Figure B-21 and Table B-9. The area values were
automatically back calculated by the software when the peak load was reached. The average flexural
modulus was 364,788 ± 41,344 psi and the average flexure strength was 6,816 ± 942 psi.
Flexural Stress Vs Flexural Strain
. . * -*
.. ./j* ' j>*.'J»**TI ^\j
0-01 0.02 0.05 0.04 0.05 0.06 0.07 O.OS
0.09
Flsxural Strain, In/in
Figure B-21. Edmonton 2: Stress - Strain Curves from Flexural Testing
Table B-9. Edmonton 2: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev.
Area
(in.2)
0.0032
0.0038
0.0029
0.0029
0.0029
0.0038
0.0031
0.0043
0.0035
0.0043
0.0034
0.0043
0.0029
0.0036
0.0033
Peak Load
(Ib)
15.41
29.33
17.97
17.59
16.90
24.94
22.36
25.39
27.11
27.15
24.38
32.84
22.53
25.90
26.76
23.77
4.97
Peak Stress
(psi)
4,816
7,718
6,197
6,066
5,828
6,563
7,213
5,905
7,746
6,314
7,171
7,637
7,769
7,194
8,109
6,816
942
Flexural
Modulus
(psi)
321,708
369,676
339,927
337,929
330,974
358,769
367,341
305,892
397,898
361,953
331,949
438,531
389,619
366,456
453,201
364,788
41,344
B-16
-------
B. 1.3.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved CIPP liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure B-22. The hardness of the surface exposed to the
flow (inner surface) was found to be only slightly lower than that of the protected (outer) surface,
suggesting little, if any, softening or erosion of the resin on the inner surface of the tube during its service
life. Differences may also be expected due to the initial presence of the sealing layer on the internal
surface.
Edmonton 200mm DINNER
Weighted average of inner surface 68.2 ± 0.7
Weighted average of outer surface 79.2 ± 1.0
I
15
r
-
£
~
.
9 10 11 12 13 14 15 16 17 18 19 20
Specimen
Figure B-22. Edmonton 2: Shore D Hardness Readings from Inner and Outer Surfaces
B.I.3.10 Short-Term Buckling Test. For the short-term buckling test, a 30 in. long piece of full
circumference was cut from the sample and housed inside a 10 in. diameter steel tube 30 in. in length with
a similar test configuration to that described for the Edmonton 10 in. (250 mm) sample.
Provision was made to apply a high pressure using the TTC's EPAD but the liner collapsed under the
supply line water pressure at around 20 psi before the N2 was released to the accumulator (see Figure B-
23). This pressure is equivalent to approximately a 46 ft head of water above the pipe.
Figure B-23. Edmonton 2: Short-Term Buckling Test Setup
B-17
-------
B.l.3.11 Glass Transition Temperature. The calculated Tg values are summarized in Table B-10 for
the Edmonton 200 mm CIPP sample. The average Tg for the field samples was 112.91°C (+/- 1.95°C) as
measured bv ASTM Method E1356-08 with DSC.
Table B-10. Edmonton 2: Tg Determination (200 mm CIPP Liner)
Sample
Edmonton (200 mm)
Edmonton (200 mm)
Edmonton (200 mm)
Run
1
2
3
Tg (°C)
112.59
111.13
115.00
B.2
City of Houston
In this section, the test results performed on 21 in. and 18 in. diameter CIPP liners exhumed near
Riverview and Blue Willow Drive, Houston, Texas are presented.
B.2.1 Houston Sample 1: A 16- to 17-Year Old CIPP Liner in a 21 in. Concrete Pipe. The
sample was retrieved from near Riverview and Blue Willow Drive, Houston, Texas, on May 6, 2013. The
lined section of pipe was being replaced in an ongoing contract and it was not possible to retrieve the liner
within the host pipe as an intact sample. The depth from the ground surface to the flow line of the pipe
was approximately 10.1 ft. The information on the host pipe and liner is shown in Table B-l 1.
Table B-ll. Houston 1: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Concrete pipe, 21 in. diameter
10.65 mm (laboratory measurement)
Not available
Not available
Not available
Not available
Not available
1996 to 1997
Not available
Not available
The retrieval process and the retrieved sample are shown in Figure B-24. The specimens were received at
the TTC South Campus Lab Facility on May 16, 2013.
B.2.1.1 Visual Inspection. In the field, the sample was observed to be brittle and uneven with visible
fibers, but it was not clear to what extent this was observed due to the sample removal process from the
host pipe. When received at the TTC, the sample was found to be in good condition relative to the other
CIPP samples retrieved. As indicated below, the test results were in the normal range.
B-18
-------
B.2.1.2 Annular Gap. Only a sample of the liner was recovered and no annular gap data were
obtained for this sample.
Figure B-24. Houston 1: Retrieval of the Sample (left) and Received Sample (right)
B.2.1.3 Environmental Service Conditions. 2 g of waste material was scooped from the inside and
outside surfaces of the sample and mixed in 200 mL of distilled water stored in a bottle. The pH was
measured separately using pH-indicator strips. The pH of the outside sample was found to be 5, whereas
the pH of the inside sample was between 4 and 5.
B.2.1.4 Ovality. A profile plotter was used to accurately map any deformation inside the liner.
Continuous readings were taken around the circumference of three cross-sections spaced 2 in. apart and
averaged. The liner was found to be approximately circular with reference to its center (see Figure B-25).
The ovality of the liner was found to be around 1.4%.
Profile Plot - Houston - 21 in. Liner
12
Figure B-25. Houston 1: Ovality of the Liner
B-19
-------
B.2.1.5 Thickness. A total of 60 readings were taken on 10 1 in. x 1 in. samples cut from different
locations of the liner specimen. The thickness was measured randomly using a micrometer with a
resolution of ± 0.0025 mm. The average thickness was found to be 10.65 mm ± 0.35 mm as shown in
Figure B-26. The design thickness was not available.
Houston 21 inch
Tditkncs 10.65 mm 10.35 mm
E
2
I
i
Measured specimens
Figure B-26. Houston 1: Average Thickness of the Sample
B.2.1.6 Specific Gravity. The specific gravity of the liner was measured on 10 1 in. x 1 in. samples in
accordance with the ASTM D792 standard. The specific gravity values from the sample are shown in
Figure B-27. The obtained values were between 1.15 and 1.19. The average specific gravity was 1.17.
Houston 21 inch
Awrjge 1.1710.02
10
Number of Samples
Figure B-27. Houston 1: Measured Specific Gravity
B.2.1.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
liner using a table saw and a band saw. The type II specimen dimensions were used for the ASTM D638
tensile test. The sides of the specimens were smoothed using a grinder. A total of 15 specimens were
B-20
-------
prepared and tested. The tensile test results are presented in Figure B-28 and Table B-12. The average
tensile strength was 3,409 ± 405 psi. The average tensile modulus was calculated to be 465,321 ± 56,119
psi.
Tensile Modulus of Elasticity
4000
3500
1100
1000
Strain, in/in
Figure B-28. Houston 1: Stress - Strain Curves from Tensile Testing
Table B-12. Houston 1: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.2133
0.1906
0.2074
0.1975
0.2040
0.2255
0.2407
0.2249
0.2393
0.2021
0.2432
0.2287
0.2218
0.2176
0.1971
Peak Load
(Ib)
772.52
711.13
796.81
634.73
727.52
540.45
850.97
661.95
870.90
635.53
848.50
854.63
830.99
787.05
574.79
739.90
108.67
Peak Stress
(psi)
3,622
3,731
3,842
3,214
3,566
2,397*
3,535
2,943
3,639
3,145
3,489
3,737
3,747
3,617
2,916
3,409
405
Tensile
Modulus
(psi)
448,935
442,826
438,923
541,844
347,069*
546,300
558,187
450,182
469,616
465,297
388,252
463,445
497,816
472,955
448,177
465,322
56,119
*Result is not within ± 25% RPD.
B.2.1.8 Flexural Test (ASTMD790). A total of 15 specimens were prepared for ASTM D790
flexure tests. The flexural test results are presented in Figure B-29 and Table B-13. The area values were
B-21
-------
automatically back calculated by the software when the peak load was reached. The average flexural
modulus was 337,638 ± 50,522 psi and the average flexure strength was 6,893 ± 842 psi.
Flexural Stress Vs Flexural Strain
Sample!
Sample 2
Samples
Sampled
SumpleS
Samp*e6
Sample I
Samples
Sample 9
Sample 10
Sample II
— Sample 12
— Sample 13
Sample 14
Sample IS
0.01 0.02 oat 0.04 0.05 0.06
Flexural Strain, In/In
Figure B-29. Houston 1: Stress - Strain Curves from Flexural Testing
Table B-13. Houston 1: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev.
Area
(in.2)
0.0168
0.0131
0.0121
0.0126
0.0152
0.0277
0.0205
0.0201
0.0208
0.0189
0.0190
0.0190
0.0225
0.0251
0.0326
Peak Load
(Ib)
138.46
96.82
93.88
92.66
114.30
226.59
130.92
124.38
145.03
117.30
131.39
124.68
146.44
143.53
179.00
133.69
34.38
Peak Stress
(psi)
8,242
7,391
7,759
7,354
7,520
8,180
6,386
6,188
6,973
6,206
6,915
6,562
6,508
5,718
5,491
6,893
842
Flexural
Modulus
(psi)
368,480
349,728
402,052
353,994
370,726
370,281
369,185
266,826
367,612
321,064
382,892
264,659
326,680
328,048
222,348*
337,638
50,522
*Result is not within ± 25% RPD.
B.2.1.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. A total of 200 readings were taken on the inner and outer surfaces of the
liner specimens. The average recorded hardness values are shown in Figure B-30. The hardness of the
B-22
-------
surface exposed to the flow (inner surface) was found to be almost the same as that of the protected
(outer) surface. However, the standard deviation of the recorded data was found to be large compared to
the test results for other liners, especially for the outer surface. Differences may also be expected due to
the initial presence of the sealing layer on the internal surface.
Houston 21 inch
INNtR IdUItK
! of Inner Surface bl.2 i 4.SH3
Average of Outer Surface 61.3 ± 7.03
30
Ml
il 1
1 2 3
Specimen
Figure B-30. Houston 1: Shore D Hardness Readings from Inner and Outer Surfaces
B.2.1.10 Glass Transition Temperature. The calculated Tg values are summarized in Table B-14 for
the Houston 21 in. CIPP sample. The average Tg for the field samples was 119.91°C (+/- 1.91°C) as
measured by ASTM Method E1356-08 with DSC.
Table B-14. Houston 1: Tg Determination (21 in. CIPP Liner)
Sample
Houston (21 in.)
Houston (21 in.)
Houston (21 in.)
Run
1
2
3
Tg (°C)
117.71
121.14
120.87
B.2.2 Houston Sample 2: A 16- to 17-Year Old CIPP Liner in an 18 in. Concrete Pipe. The
sample was retrieved from near Riverview and Blue Willow Drive, Houston, TX on May 10, 2013. The
lined section of pipe was being replaced in an ongoing contract and it was not possible to retrieve the liner
and host as an intact sample. The depth from the ground surface to the flow line of the pipe was
approximately 11.5 ft. The information on the host pipe and liner is shown in Table B-15.
The sample was retrieved from the same manhole as the Houston 21 in. CIPP sample and the retrieved
sample is shown in Figure B-31. The specimens were received at the TTC South Campus Lab Facility on
May 16, 2013.
Table B-15. Houston 2: Host Pipe and Liner Information
iHost
pipe
Concrete
pipe,
18
in.
diameter |
B-23
-------
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
10.95 mm (laboratory measurement)
Not available
Not available
Not available
Not available
Not available
1996 to 1997
Not available
Not available
Figure B-31. Houston 2: Received 18 in. CIPP Sample
B.2.2.1 Visual Inspection. In the field, the sample was observed to be brittle and uneven with visible
fibers, but it was not clear to what extent this was observed due to the sample removal process from the
host pipe. When received at the TTC, the sample was found to be in good condition relative to the other
CIPP samples retrieved. As indicated below, the test results were in the normal range.
B.2.2.2 Annular Gap. Only a sample of the liner was recovered and no annular gap data were
obtained for this sample.
B.2.2.3 Environmental Service Conditions. 2 g of waste material was collected from the inner and
outer surfaces of the sample and mixed with 200 mL of distilled water stored in a bottle. The pH of the
water was measured separately using pH-indicator strips and it was found that the pH of the outside
sample was between 4 and 5 while the pH of the inside sample was found to be 6 to 7.
B.2.2.4 Ovality. A profile plotter was used to accurately map any deformation inside the liner. The
system features a LVDT connected to a motor-gear system that rotates around the inner circumference of
the liner. An encoder system provides position information regarding the location around the pipe at
which the data are taken. The liner was found to be approximately circular with reference to its center
(see Figure B-32). The ovality of the liner was found to be around 1.7%.
B-24
-------
Profile Plot - Houston -18 in. Liner
Figure B-32. Houston 2: Ovality of the Liner
B.2.2.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness was found to be 10.95 mm ± 0.23 mm as shown in Figure B-33.
The design thickness was not available.
Houston 18 inch
12.0
SI 5? S3 54 55 56 5/ SB VI SIC SI] 512 513 51J 515 516 517 518 519 520
Measured specimens
Figure B-33. Houston 2: Average Thickness of the Sample
B-25
-------
B.2.2.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with the ASTM D792 standard. The specific gravity values from the sample are shown in
Figure B-34. The obtained values were between 1.15 and 1.19. The average specific gravity was 1.18.
Houston 18 inch
Avpragp 1.18 + 0.01
1.40 r „
1.20
fl.10
y
0.20
0.10
0.00
- 5
0
] £
i 2
\ 5
£
^ r
! I
4 r
•
i S
»
11 r
! r
1 <•
r
s
«
/ S 3 HI II 12 13 14 I'j 10 I/ 18 19
Number of Samples
Figure B-34. Houston 2: Measured Specific Gravity of the Liner
B.2.2.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the liner
using a table saw and a band saw. The Type II specimen dimension was used for the ASTM D638 tensile
test. The sides of the specimens were smoothed using a grinder. A total of 15 specimens were prepared
and tested.
The tensile test results are presented in Figure B-35 and Table B-16. The average tensile strength was
3,252 ± 456 psi and the average tensile modulus was 450,985 ± 62,184 psi. Data for Specimen 2 were not
obtained due to premature failure of the sample which was thought to be from the misalignment of the
specimen along the pneumatic grips.
Tensile Modulus of Elasticity
.,..,„,
0.06
Strain, In/in
Figure B-35. Houston 2: Stress - Strain Curves from Tensile Testing
B-26
-------
Table B-16. Houston 2: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.2090
Peak Load
(Ib)
661.87
Peak Stress
(psi)
3,167
Tensile
Modulus
(psi)
489,680
No data due to machine error
0.2249
0.2713
0.2151
0.2124
0.2500
0.2262
0.2642
0.2581
0.2451
0.2508
0.2296
0.2404
0.2240
670.40
705.36
712.68
815.80
864.89
663.37
731.87
838.19
720.01
991.97
839.41
659.62
878.97
768.17
103.12
2,981
2,600
3,313
3,841
3,460
2,933
2,770
3,248
2,938
3,955
3,656
2,744
3,924
3,252
456
467,179
520,625
489,362
491,600
522,812
475,687
388,706
389,415
323,123*
408,373
462,991
370,489
513,751
450,985
62,184
*Result is not within ± 25% RPD.
B.2.2.8 Flexural Test (ASTMD790). A total of 15 specimens were prepared for ASTM D790
flexure tests. The flexure test results are presented in Figure B-36 and in Table B-17. The area values
were automatically back calculated by the software when the peak load was reached. The average
flexural modulus was 338,565 ± 26,467 psi and the average flexure strength was 7,204 ± 532 psi. Data
were not included in the table for both Samples 6 and 10. For Sample 6, there was a mistake in the input
for the span length and, for Sample 10, there was a problem with the machine grip.
Flexural Stress Vs Flexural Strain
Sample 1
Sampl*2
Samples
Sample «
Samples
Sample 6
Sample?
Samples
Sample 9
Sample 10
Sample 1J
— Sample 12
Sample 13
Sampl.14
Sample 15
Flexural Strain, In/In
Figure B-36. Houston 2: Stress - Strain Curves from Flexural Testing
B-27
-------
Table B-17. Houston 2: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0162
0.0151
0.0155
0.0163
0.0157
Peak Load
(Ib)
110.20
119.37
122.78
105.70
123.91
Peak Stress
(psi)
6,802
7,905
7,921
6,485
7,892
Flexural
Modulus
(psi)
305,529
366,794
336,622
307,590
360,625
Not included due to wrong data input
0.0201
0.0212
0.0191
148.39
144.39
141.16
7,383
6,811
7,391
342,912
306,866
360,154
No data due to machine error
0.0199
0.0220
0.0209
0.0197
0.0211
148.13
145.30
147.40
147.22
136.96
133.92
15.45
7,444
6,605
7,053
7,473
6,491
7,204
532
364,462
310,968
329,906
382,436
326,484
338,565
26,467
B.2.2.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. A total of 400 readings were taken on the inner and outer surfaces of the
liner specimens. The average recorded hardness values are shown in Figure B-37. The hardness of the
surface exposed to the flow (inner surface) was found to be only slightly lower than that of the protected
(outer) surface, suggesting little, if any, softening or erosion of the resin on the inner surface of the tube
V / OO O • J? O
during its service life. Differences may also be expected due to the initial presence of the sealing layer on
the internal surface.
Houston 18 inch
Average nf Inner Surface G5.-1 * 2.46
AwrdE*-' uf Ou'ILT Sui(d
-------
B.2.2.10 Glass Transition Temperature. The calculated Tg values are summarized in Table B-18 for
the Houston 18 in. CIPP sample. The average Tg for the field samples was 119.69°C (+/- 1.80°C) as
measured bv ASTM Method E1356-08 with DSC.
Table B-18. Sample Tg Determination (18 in. CIPP Liner)
Sample
Houston (18 in.)
Houston (18 in.)
Houston (18 in.)
Run
1
2
3
Tg (°C)
121.71
118.27
119.10
B.3
City of Indianapolis
B.3.1 Indianapolis: An Approximately 25-Year Old CIPP Liner in a 42-in. Brick Sewer. This
report contains the test results performed on a liner exhumed from the intersection of N. Illinois St. and
W. Vermont St. in Indianapolis, Indiana (approximate street address: 343 North Illinois Street,
Indianapolis, IN 46204) on April 29, 2013. The sample was collected from a lined host pipe of 42-in.
diameter. The liner was installed in approximately 1986-1989 by Insituform for the City of Indianapolis.
The host pipe runs beneath Illinois St. from Washington St. in the south to 16th St. in the north,
approximately 5,000 If. This combined sewer has periods of low flow which leads to high odors. The
backfill in the area of the pipe is typically sand and the groundwater depth is anticipated to be 10 to 12 ft
below grade. The host pipe invert was at a depth of approximately 20 ft below ground level. The host
pipe and liner information are shown in Table B-19.
The sample was originally going to be cut from above the spring line, however fiber optic conduits were
found inside the sewer pipe at the 10 o'clock and 2 o'clock positions in the pipe on the north side of the
manhole (towards Vermont Street). The samples were cut as 25-in. by 25-in. samples (Insituform would
also collect a sample of the same size downstream of the Battelle sample for its own use), but it was not
possible to lift this size of sample to the surface through the manhole. Hence, each original sample was
cut into two 12.5-in. by 25-in. pieces. All sample pieces were successfully raised to the surface. The
exhumed samples are shown in Figure B-38. The specimens were received at the TTC South Campus
Lab Facility on Monday, October 22, 2012.
Table B-19. Indianapolis: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Brick sewer 42-in. diameter
Information not available
Information not available
Information not available
Information not available
Information not available
Information not available
1986-1989
Insituform Technologies
Information not available
B-29
-------
Figure B-38. Indianapolis: Retrieval of the Sample (left) and Received Sample (right)
B.3.1.1 Visual Inspection. The two panels received were in good condition (see Figure B-39).
Figure B-39. Indianapolis: Panel 1 of the CIPP Liner (left) and
Panel 2 of the CIPP Liner (right)
B.3.1.2 Annular Gap. The liner in the field was found to be close-fitted to the host pipe with an
annular gap no more than 0.406 mm (0.016 in.).
B.3.1.3 Environmental Service Conditions. 2 g of waste material was collected from the inner and
outer surfaces of the sample and mixed with 200 mL of distilled water stored in a bottle. The pH was
measured separately using pH-indicator strips. For Panel 1, the pH inside the liner was 5 and outside was
6 to 7. For Panel 2, the pH of the inside and outside was more similar, both around 6 to 7.
B.3.1.4 Ovality. The sample received was a curved plate (a portion of the liner from the 3 o'clock to
5 o'clock positions of the circumference in the field) and therefore an ovality test was not applicable.
B.3.1.5 Thickness. A total of 180 readings were taken on 30 1 in. x 1 in. samples (15 specimens
from Panel 1 and the other 15 from Panel 2) cut from different locations of the specimen. The thickness
was measured randomly using a micrometer with a resolution of ±0.0025 mm.
B-30
-------
The average thickness of Panel 1 was found to be 22.4 mm ± 0.21 mm (see Figure B-40) and the average
thickness of Panel 2 was 21.9 mm ± 0.21 mm (see Figure B-41). The design thickness was not available
and therefore no comparison was made.
Panel 1
30.0
25.0
£ 20.0
E
i(j 15.0
U
10.0
5.0
0.0
Average 22.4mm ±0.21 mm -
11!111111111"
SI S2 S3 S4 S5 S6 S7 S8 S9 S10 Sll S12 S13 S14 S15
Measured specimens
Figure B-40. Indianapolis: Average Thickness of Panel 1
Panel 2
23.0
22.5
E 22.0
E
i/T
ffi 21.5
c
y
i^ 21.0
20.5
20.0
m MM
Average 21.9mm ± 0.21 mm
I I I
SI S2 S3 S4 S5 S6 S7 S8 S9 S10 Sll S12 S13 S14 S15
Measured specimens
Figure B-41. Indianapolis: Average Thickness of Panel 2
B-31
-------
B.3.1.6 Specific Gravity. The specific gravity of the liner was measured on 30 1 in. x 1 in. samples
(15 from Panel 1 and 15 from Panel 2) in accordance with ASTM D792. The specific gravity values from
Panel 1 and Panel 2 are shown in Figures B-42 and B-43. The obtained values were between 1.05 and
1.11. The average specific gravity of Panel 1 was 1.07 and Panel 2 was 1.08.
Panel 1
Average 1.07 ± 0.02
10
11
12
13
1 2 3
Number of Samples
Figure B-42. Indianapolis: Measured Specific Gravity of Panel 1
14
15
Panel 2
Average 1.08 + 0.01
10
11
12
13
14
15
Number of Samples
Figure B-43. Indianapolis: Measured Specific Gravity of Panel 2
B.3.1.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved CIPP liner using a table saw and a band saw. Due to the high thickness value of the sample, the
Type III specimen dimensions from the standard were used. Tensile specimens were machined to 0.55 in.
to meet the limit provided by ASTM D638 (see Figure B-44). The tensile test setup is shown in Figure B-
45.
B-32
-------
Figure B-44. Indianapolis: Five Panel 1 Specimens (left) and Five Panel 2 Specimens (right)
Prepared for Tensile Testing
Break Inside the Jaw
of Extensa
Figure B-45. Indianapolis: Tensile Testing in Accordance with ASTM D638 (left)
and Samples after Test (right)
The tensile test results are presented in Figures B-46 and B-47 and Tables B-20 and B-21. The average
tensile strength for Panel 1 was 2,826 ± 296 psi and, for Panel 2, was 2,611 ±241 psi. The average
tensile moduli were 356,783 ± 37,515 psi and 345,805 ± 67,528 psi, respectively. A visible crack was
observed early in the test of Sample 5 from Panel 2, but the tensile strength and modulus properties still
tested in the range of the other samples.
B-33
-------
Tensile Modulus of Elasticity
3500
3000
2500
2000
1500
1000
500
0.2 0.25
Strain, in/in
0.35
0.4
0.45
Figure B-46. Indianapolis: Stress - Strain Curves from Tensile Testing of Panel 1
Tensile Modulus of Elasticity
3100
3000
2500
1500
1000
IJ.HS
(1.1 I). IS
Strain, In/En
Figure B-47. Indianapolis: Stress - Strain Curves from Tensile Testing of Panel 2
Table B-20. Indianapolis: Tensile Test Results (Panel 1)
Sample
ID
1
2
3
4
5
Average
St. Dev
Area
(in.2)
0.4068
0.3940
0.4027
0.4172
0.3853
Peak Load
(Ib)
1,081.02
964.65
1,201.72
1,176.31
1,239.83
1,132.71
110.74
Peak Stress
(psi)
2,657
2,448
2,985
2,820
3,218
2,826
296
Tensile
Modulus
(psi)
320,584
325,000
361,417
363,148
413,766
356,783
37,515
B-34
-------
Table B-21. Indianapolis: Tensile Test Results (Panel 2)
Sample
ID
1
2
3
4
5
Average
St. Dev
Area
(in.2)
0.4341
0.3795
0.3800
0.3804
0.3629
Peak Load
(Ib)
1,048.61
931.33
1,065.00
930.55
1,065.02
1,008.10
70.76
Peak Stress
(psi)
2,416
2,454
2,803
2,446
2,935
2,611
241
Tensile
Modulus
(psi)
312,560
436,579
378,849
343,537
257,500*
345,805
67,528
*Result is not within ± 25% RPD.
B.3.1.8 Flexural Test (ASTMD790). The flexural specimens were cut shorter than the required
length mentioned in ASTM D790 due to the inadequate sample geometry. The specimens prepared from
Panel 1 were 11 in. long while for Panel 2 they were 13 in. long. The sides of the specimens were
smoothed using a grinder. The flexure test results are presented in Figures B-48 and B-49 and Tables B-
22andB-23.
The area values shown in the tables are the area back calculated by the software when the load reached its
peak. The average flexural moduli of Panel 1 and Panel 2 were found to be 236,254 ± 23,169 psi and
238,273 ± 38,439 psi, respectively. The average flexural strengths for Panel 1 and Panel 2 were found to
be 4,892 ± 408 psi and 4,531 ± 339 psi.
Flexural Stress Vs Flexural Strain
•s
a.
6000
5000
4000
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05
Flexural Strain, in/in
Figure B-48. Indianapolis: Stress - Strain Curves from Flexural Testing of Panel 1
B-35
-------
Flexural Stress Vs Flexural Strain
•s
0.
6000
5000
4000
3000
2000
1000
0
Sam 3le 5
Sample 1
Sample 2
Samp
Ie4
Samp e 3
Sample 1
Sample 2
— Sample 3
—Sam pie 4
Sample 5
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
Flexural Strain, in/in
Figure B-49. Indianapolis: Stress - Strain Curves from Flexural Testing of Panel 2
Table B-22. Indianapolis: Flexural Test Results (Panel 1)
Sample ID
1
2
3
4
5
Average
St. Dev
Area
(in.2)
0.0336
0.0271
0.0313
0.0270
0.0376
Peak Load
Ob)
148.59
129.64
144.71
144.19
199.00
153.23
26.59
Peak Stress
(psi)
4,422
4,784
4,623
5,340
5.293
4,892
408
Flexural
Modulus
(psi)
202,890
249,791
224,674
241,390
262,527
236,254
23,169
Table B-23. Indianapolis: Flexural Test Results (Panel 2)
Sample ID
1
2
3
4
5
Average
St. Dev
Area
(in.2)
0.0670
0.0420
0.0499
0.0430
0.0404
Peak Load
(Ib)
295.55
194.64
204.96
192.24
203.32
218.14
43.61
Peak Stress
(psi)
4,411
4,634
4,107
4,471
5,033
4,531
339
Flexural
Modulus
(psi)
172,925*
260,129
236,399
252,906
269,006
238,273
38,439
*Result is not within ± 25% RPD.
B-36
-------
B.3.1.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. A total of 400 readings were taken on the inner and outer surfaces of the
liner specimens. The average recorded hardness values are shown in Figures B-50 and B-51. It can be
seen that Panel 1 and Panel 2 show differences in the comparative hardness results between the inner and
outer surfaces. The average outer surface hardness is similar, but the average inner surface hardness for
Panel 2 is noticeably lower than for Panel 1.
Panel 1
INNER • OUTER
Average ol Innwi Surfdttf b9./ 14.6
A'. L" jtr ul UuU-r Surfdce f>!>.2 1 2.9
a «K>
Specimen
Figure B-50. Indianapolis: Shore D Hardness Readings for Panel 1 Inner and
Outer Surfaces
Panel 2
.IINNtR BtHJItH
of Ifitwi 5.1
Average of ouier Surface 66.114.2
Specimen
Figure B-51. Indianapolis: Shore D Hardness Readings for Panel 2 Inner and
Outer Surfaces
B-37
-------
B.3.1.10 Glass Transition Temperature. The calculated Tg values are summarized in Table B-24 for
the Indianapolis samples (Panel 1 and Panel 2). The average Tg for both of the field samples was
125.23°C (+/- 5.36°C) as measured by ASTM Method E1356-08 with DSC.
Table B-24. Indianapolis Tg Determination (Panels 1 and 2 CIPP Liner)
Sample
Indianapolis Panel 1
Indianapolis Panel 1
Indianapolis Panel 1
Indianapolis Panel 2
Indianapolis Panel 2
Indianapolis Panel 2
Run
1
2
3
1
2
3
Tg (°C)
120.48
117.88
126.09
131.31
130.62
125.02
B.4
City of Nashville
This section contains the test results performed on two liners exhumed from the City of Nashville,
Tennessee.
B.4.1 Nashville Sample 1: A 19-Year Old CIPP Liner Installed in an 8 in. Concrete Pipe. The
first sample was retrieved from 625 Dunston Drive, Nashville, Tennessee on September 21, 2013. The
host pipe was at a depth of 4 ft to 5 ft below the ground surface. The host pipe and liner information are
provided in Table B-25.
Table B-25. Nashville 1: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Concrete pipe, 8 in. diameter
5.6 mm (measured in laboratory)
Information not available
Information not available
Information not available
Information not available
Information not available
1994
Mid-South Partners (Insituform Technologies
Inc.)
Information not available
The retrieval process and the retrieved sample are shown in Figure B-52. The specimens were received at
the TTC South Campus Lab Facility on October 9, 2013.
B.4.1.1 Visual Inspection. The sample was found to be in excellent condition and closely fit inside
the host pipe.
B.4.1.2 Annular Gap. The annular gap was measured using a feeler gauge. Eight readings were
taken of the annular gap on the remaining host pipe and are shown in Table B-26.
B-38
-------
Figure B-52. Nashville 1: Retrieval of the Sample (left) and Measuring Annular Gap on the
Received Sample (right)
Table B-26. Nashville 1: Reading of Feeler Gauge on the "Remaining Host Pipe'
Position
12:00
1:30
3:00
5:00
6:00
7:30
9:00
11:00
Gap Measured
0.016 in. (0.41mm)
0.016 in. (0.41mm)
0.016 in. (0.41mm)
0.000 in. (0.000 mm)
0.000 in. (0.000 mm)
0.000 in. (0.000 mm)
0.031 in. (0.79mm)
0.0 . (0.000 mm)
B.4.1.3 Environmental Service Conditions. 20 g of waste material on the inside of the sample was
collected and stored in a bottle filled with 200 mL of distilled water. The distilled water was stirred and
pH was measured separately using pH-indicator strips. The pH was found to be between 10 and 11.
B.4.1.4 Ovality. A profile plotter was used to accurately map any deformation inside the liner. The
liner was found to be approximately circular with reference to its center (see Figure B-53). The ovality of
the liner was found to be 3.7%.
B.4.1.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the liner specimen. The thickness was measured randomly using a micrometer with a
resolution of ±0.0025 mm. The average thickness was found to be 5.60 mm ± 0.32 mm as shown in
Figure B-54. The design thickness was unavailable so no comparison was made.
B-39
-------
Profile Plot - Nashville A- 8 in. Liner
Figure B-53. Nashville 1: Ovality of the Liner
Nashville Ounston
Average ThickrWH 5.60 nun • 0.32 n
SI 52 S3 54 55 56 57 58 59 S10 511 512 513 SH S15 S16 S17 SIS SW SM
Measured specimens
Figure B-54. Nashville 1: Average Thickness of the Sample
B.4.1.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values from the sample are shown in Figure B-55.
The obtained values were between 1.08 and 1.17. The average specific gravity of the liner was 1.14.
B.4.1.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
liner using a table saw and a band saw. The Type II specimen dimension was used for the ASTM D638
tensile test. The sides of the specimens were smoothed using a grinder. A total of 15 specimens were
prepared and tested. The tensile test results are presented in Figure B-56 and Table B-27. The average
tensile strength was 3,436 ± 274 psi. The average tensile modulus was calculated to be 375,807 ± 48,729
psi.
B-40
-------
Nashville Duston
Average 1.14 ±0.03
1.30
1.20
£• i.oo
2 0.90
u 0.80
: 0.70
,5" 0.60
030
0.20
0.10
0.00 r-
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure B-55. Nashville 1: Measured Specific Gravity of the Liner
Table B-27. Nashville 1: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1025
0.1061
0.1059
0.0965
0.1002
0.1163
0.1101
0.1111
0.1185
0.0976
0.1085
0.1186
0.1049
0.1297
0.0992
Peak Load
(lb)
376.41
325.39
393.01
326.24
349.03
404.54
367.00
380.20
469.79
339.33
316.35
418.99
382.88
393.42
339.15
372.11
41.40
Peak Stress
(psi)
3,672
3,067
3,711
3,381
3,483
3,478
3,333
3,422
3,964
3,477
2,916
3,533
3,650
3,033
3,419
3,436
274
Tensile
Modulus
(psi)
391,267
439,783
432,223
287,329
350,412
385,196
343,115
420,735
427,424
284,745
361,284
413,245
353,638
395,794
350,909
375,807
48,729
B-41
-------
Tensile Modulus of Elasticity
002
Figure B-56. Nashville 1: Stress - Strain Curves from Tensile Testing
B. 4.1.8 Flexural Test (ASTM D 790). A total of 15 specimens were prepared for ASTM D790
flexure tests. The flexure test results are presented in Figure B-57 and Table B-28. The area values were
automatically back calculated by the software when the peak load was reached. The average flexural
modulus was 301,724 ± 42,399 psi and the average flexure strength was 6,832 ± 864 psi.
Flexural Stress Vs Flexural Strain
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.03 0.09
Flexural Strain, in/In
Figure B-57. Nashville 1: Stress - Strain Curves from Flexural Testing
B.4.1.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved CIPP liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure B-58. The hardness of the surface exposed to the
flow (inner surface) was found to be only slightly lower than that of the protected (outer) surface,
suggesting little, if any, softening or erosion of the resin on the inner surface of the tube during its service
life. Differences may also be expected due to the initial presence of the sealing layer on the internal
surface.
B-42
-------
Table B-28. Nashville 1: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0044
0.0043
0.0043
0.0041
0.0037
0.0037
0.0049
0.0060
0.0051
0.0044
0.0056
0.0071
0.0046
0.0056
0.0053
Peak Load
(Ib)
25.44
30.22
23.52
29.52
26.13
23.86
41.88
43.98
36.96
25.19
36.53
47.58
31.29
46.49
33.53
33.47
8.37
Peak Stress
(psi)
5,782
7,028
5,470
7,200
7,062
6,449
8,547
7,330
7,247
5,725
6,523
6,701
6,802
8,302
6,326
6,832
864
Flexural
Modulus
(psi)
263,620
315,296
276,162
311,503
338,642
308,482
386,728
294,335
334,861
258,893
291,689
214,178*
288,000
356,428
287,057
301,724
42,399
*Result is not within ± 25% RPD.
Nashville Dunston
INNER n OUTER
Average of Inner Surface 65.2 + 3.16
Average of Outer Surface 72.2 ± 2.30
•O
5
75
60 fr
45
30
15
r~
.
s
u>
a,
^t
1 '
i
i
r--"c
•!
D
.
l£Jr
H
^ic
S
O r
-i
r-.' n
•>
ll
O •!
I
K-
K^
Ko
•)
rsic
i
10 11
Specimen
13
Figure B-58. Nashville 1: Shore D Hardness Readings from Inner and Outer Surfaces
B.4.1.10 Glass Transition Temperature. The calculated Tg values are summarized in Table B-29 for
the Nashville (Dunston) CIPP sample. The average Tg for the field samples was 120.37°C (+/- 2.14°C)
as measured by ASTM Method E1356-08 with DSC.
B-43
-------
Table B-29. Nashville 1: Tg Determination (Dunston CIPP Liner)
Sample
Nashville (Dunston)
Nashville (Dunston)
Nashville (Dunston)
Run
1
2
3
Tg (°C)
121.79
121.42
117.91
B.4.2 Nashville 2: A 9-Year Old CIPP Liner in an 8 in. Non-reinforced Concrete Pipe. The
liner sample was retrieved from 5100 Wyoming Avenue, Nashville, Tennessee on September 21, 2013.
The host pipe was at 4 ft to 5 ft below the ground surface. The host pipe and liner information are shown
in B-30.
Table B-30. Nashville 2: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Concrete pipe, 8 in. diameter
7.05 mm (laboratory measurement)
Information not available
Information not available
Information not available
Information not available
Information not available
2004
Miller Pipeline
Information not available
The retrieval process and the retrieved sample are shown in Figure B-59. The sample was received at
TTC South Campus Facility on October 9, 2013.
B.4.2.1 Visual Inspection. The sample was found to be in excellent condition.
B.4.2.2 Annular Gap. The annular gap was measured using a feeler gauge on the remaining host
pipe. Eight readings were taken and are shown in Table B-31.
B.4.2.3 Environmental Service Conditions. 20 g of waste material was collected from the inside of
the sample and mixed with 200 mL of distilled water. The pH of the water was measured using pH-
indicator strips and found to be between 9 and 10. The pH also was measured in a similar manner on the
collected soil sample and the value obtained was found between 6 and 7.
B.4.2.4 Ovality. A profile plotter was used to accurately map any deformation inside the liner. The
liner was found to be approximately circular with reference to its center (see Figure B-60). The ovality of
the liner was found to be 3.6%.
B-44
-------
Figure B-59. Nashville 2: Retrieval of the Sample (left) and Received Sample (right)
Table B-31. Nashville 2: Reading of Feeler Gauge on the "Remaining Host Pipe'
Position
12:00
1:30
3:00
5:00
6:00
7:30
9:00
11:00
Gap Measured
0.046 in. (1.17mm)
0.000 in. (0.000 mm)
0.000 in. (0.000 mm)
0.016 in. (0.41mm)
0.016 in. (0.41mm)
0.000 in. (0.000 mm)
0.000 in. (0.000 mm)
0.016 in. (0.41mm)
Profile Plot - Nashville B - 8 in. Liner
Figure B-60. Nashville 2: Ovality of the Liner
B-45
-------
B.4.2.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness was found to be 7.05 mm ± 0.28 mm as shown in Figure B-61. The
design thickness was not available.
Nashville Wyoming
£
E
a"
I
ZJO
i.o
o.o
- Hittknthi /,Ub mm ± 0.28 mm
II I II II
S1 S7 S.1 S1 SB S6 S7 SB S9 S10 S11
Measured specimens
S1-1 SIS S16 517 SIB S19 S70
Figure B-61. Nashville 2: Average Thickness of the Sample
B.4.2.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values from the sample are shown in Figure B-62.
The obtained values were between 1.15 and 1.25. The average specific gravity of the liner was 1.21.
Nashville Wyoming
Average 1.21 iC.O
^ !_5_§_i_5_i_|_j_§_i_S_!_J_«_l
1.20 '
S 1.00 •
'u
0.30
0.00
1234
6 7 8 9 10 11 12 13 14 15
1C 17 18 19 20
Number of Samples
Figure B-62. Nashville 2: Measured Specific Gravity of Liner
B-46
-------
B.4.2.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
liner using a table saw and a band saw. The Type II specimen dimension was used for the ASTM D638
tensile test. The sides of the specimens were smoothed using a grinder. A total of 15 specimens were
prepared and tested. The tensile test results are presented in Figure B-63 and Table B-32. The average
tensile strength was 2,672 ± 425 psi and the average tensile modulus was 400,926 ± 79,773 psi.
Tensile Modulus of Elasticity
.1SOQ
3000
Figure B-63. Nashville 2: Stress - Strain Curves from Tensile Testing
Table B-32. Nashville 2: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1816
0.1387
0.1336
0.1403
0.1382
0.1447
0.1403
0.1455
0.2136
0.1760
0.1558
0.1445
0.1520
0.1628
0.1481
Peak Load
(Ib)
454.98
372.21
361.91
360.52
292.40
334.75
402.67
318.25
384.84
580.20
461.51
457.51
436.64
503.65
435.78
410.52
75.98
Peak Stress
(psi)
2,505
2,684
2,709
2,570
2,116
2,315
2,870
2,187
1,793*
3,297
2,962
3,166
2,873
3,094
2,942
2,672
425
Tensile
Modulus
(psi)
409,234
499,595
452,010
468,111
483,333
300,738
468,814
328,964
191,123*
408,346
429,530
395,000
381,617
387,788
409,693
400,926
79,773
* Result is not within ± 25% RPD.
B-47
-------
B.4.2.8 Flexural Test (ASTMD790). A total of 15 specimens were prepared for ASTM D790
flexure tests. The flexure test results are presented in Figure B-64 and Table B-33. The area values were
automatically back calculated by the software when the peak load was reached. The average flexural
modulus was 282,460 ± 50,774 psi and the average flexure strength was 5,497 ±916 psi. The bending
modulus values for Samples 1 to 5 were found to be noticeably lower than the other samples cut from a
different location of the same specimen. The flexural strength for Sample 10 was also noticeably lower in
value (see Figure B-64). This is attributed to a localized variation in liner properties either from the time
of installation or due to subsequent deterioration.
Flexural Stress Vs Flexural Strain
a
£
7000
6000
5000
3000
2000
1000
0.02
0.04
0.06
0.08
0.1
0.12
0.14
Flexural Strain, in/in
Figure B-64. Nashville 2: Stress - Strain Curves from Flexural Testing
B.4.2.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved CIPP liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure B-65. The hardness of the surface exposed to the
flow (inner surface) was found to be only slightly lower than that of the protected (outer) surface,
suggesting little, if any, softening or erosion of the resin on the inner surface of the tube during its service
life. Differences may also be expected due to the initial presence of the sealing layer on the internal
surface.
B.4.2.10 Glass Transition Temperature. The calculated Tg values are summarized in Table B-34 for
the Nashville (Wyoming Avenue) sample. The average Tg for the field samples was 109.43°C (± 3.79°C)
as measured by ASTM Method E1356-08 with DSC.
B-48
-------
Table B-33. Nashville 2: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0070
0.0063
0.0094
0.0085
0.0063
0.0067
0.0074
0.0078
0.0082
0.0069
0.0070
0.0070
0.0103
0.0074
0.0077
Peak Load
(Ib)
33.45
27.88
43.85
35.65
26.77
43.59
45.16
43.85
53.37
30.96
42.92
42.92
68.35
45.75
44.90
41.96
10.46
Peak Stress
(psi)
4,779
4,425
4,665
4,194
4,249
6,506
6,103
5,622
6,509
4,487
6,131
6,131
6,636
6,182
5,831
5,497
916
Flexural
Modulus
(psi)
236,019
241,460
189,627*
237,897
229,241
340,971
315,721
312,206
306,335
226,103
328,685
328,685
297,954
353,472
292,528
282,460
50,774
* Result is not within ± 25% RPD.
Nashville Wyoming INN™
Average of Innef Surface 64.6 ± 2.57
Annut of Ouln Wicc 67A 16,34
60 i
3 4 S 6 7 X 1 10 13 13 14 15 16 17 18 19 30
Figure B-65. Nashville 2: Shore D Hardness Readings from Inner and Outer Surfaces
Table B-34. Nashville 2: Tg Determination (Wyoming Avenue 8 in. CIPP Liner)
Sample
Nashville (Wyoming)
Nashville (Wyoming)
Nashville (Wyoming)
Run
1
2
3
Tg (°C)
112.81
105.34
110.15
B-49
-------
B.5
City of New York
This report contains the test results performed on three liners exhumed from 3rd Street and Willoughby
Street in New York City. The sample locations were selected by the city based on the age of the CIPP
installation and accessibility. Sample 1 was defective, and therefore was subjected to visual examination,
but not to physical testing.
B.5.1 New York Sample 1: A 24-Year Old CIPP Liner in a 12 in. Clay or Concrete Pipe. At
this location at 630A 3rd Street, Brooklyn, New York, a sample was recovered on October 16, 2012 by
cutting a liner sample from within the host pipe adjacent to an existing manhole (Figure B-66). The depth
to the invert of the host pipe at the sample location was 11.6 ft. However, the sample recovered was not
suitable for testing. The sample consisted mostly of uncured felt with very little resin. This could have
been due to significant infiltration of groundwater near the manhole, which washed away the impregnated
resin before it could be cured and hardened or due to a lack of resin saturation during the wet out process.
It was expected that mechanical testing of this soft sample would have been unlikely to produce
meaningful data, and therefore no testing was carried out.
Figure B-66. New York 1: Defective Sample Retrieved from 3rd Street
B.5.2 New York Sample 2: A 23-Year Old CIPP Liner in a 15-in. Clay Pipe. The sample was
recovered at 141 Willoughby Street, Brooklyn, New York on October 16, 2012. The host pipe and liner
information are shown in Table B-35. The invert of the host pipe was at a depth of approximately 12 ft
below ground level and the groundwater conditions could not be observed due to the sample retrieval via
a manhole.
B. 5.2.1 Visual Inspection. The liner sample was removed fairly easily compared to the previous site
containing the defective liner. The bottom half of the liner was inaccessible for removal. The liner
appeared to be in good condition. However, the interior polyurethane coating seemed to have hydrolyzed
or eroded away. The retrieval process and the retrieved sample are shown in Figures B-67 and B-68.
B-50
-------
Table B-35. New York 2: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Extra Strength Vitrified Clay Pipe 15 in.
@ 3:00 o'clock 6.8 mm and @ 9:00 o'clock 7.05
mm
AOC7-5810-PM
Esperox 5 TOP
Esperox 10
Unwoven fabric (similar to products used today)
Polyurethane, 0.015 in. thick (today CIPP liners
polyethylene coating)
use
1989-1991
Insituform
AOC LLC
Figure B-67. New York 2: Retrieval of the Sample (left) and
Retrieved Sample in the Field (right)
Figure B-68. New York 2: Images of the Inner Surface of the 23-Year Old, 36-in. Long CIPP Liner
Section Prior to Testing
B-51
-------
B.5.2.2 Annular Gap. The liner was observed to be tight to the invert of the pipe (below the 9:00
o'clock to 3:00 o'clock positions) with no annular gap. However, a small annular gap (around 0.007 in.
[0.18 mm]) was measured in the field from the 9:00 o'clock to the 3:00 o'clock positions.
B.5.2.3 Environmental Service Conditions. Not applicable due to method of removal described
above where only the top half of the liner was removed. No soil samples were collected because of
sample removal through the manhole.
B.5.2.4 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness of the liner was found to be 7.27 mm ± 0.26 mm as shown in Figure
B-69. The design thickness was unavailable; therefore, no comparison was made.
NYC 15 inch
• »••••••- Average Thickries 7.27 mm ±0.26 n
SI S2 S3 S4 S5 S6 S7 SS S9 S10 Sll S12 S13 S14 SIS S16 S17 S18 519 S20
Measured specimens
Figure B-69. New York 2: Average Thickness of the Liner Sample
B.5.2.5 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure B-70. The obtained
values were between 1.26 and 1.35. The average specific gravity was 1.31 ± 0.03.
B. 5.2.6 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved CIPP liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. A water jet cutter could not be used as the
liner was curved and too small to be mounted inside the cutting board. The tensile test results are
presented in Figure B-71 and Table B-36. The average tensile strength was 3,729 ± 369 psi and average
tensile modulus 554,100 ± 60,863 psi. The elongation at break varied from around 1.5% to 16%.
B-52
-------
NYC 15 inch
Average 1.31 ±0.03
o r~
1.40
t M
1.30 fe.rt.
5 g
rO o
1.20
1.10
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure B-70. New York 2: Measured Specific Gravity of the Liner
Tensile Modulus of Elasticity
0.1 0.12
Strain, In/In
Figure B-71. New York 2: Stress - Strain Curves from Tensile Testing
B.5.2.7 Flexural Test (ASTMD790). Specimens, as described in ASTM D790, were cut from the
retrieved CIPP liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. A water jet cutter could not be used as the
liner was curved and too small to be mounted inside the cutting board.
The flexure test results are presented graphically in Figure B-72 and are listed in Table B-37. The
average flexural modulus was 477,609 ± 28,389 psi and average flexural strength was 7,978 ± 654. All
the bending stress and bending modulus values were found to be well above the minimum values listed in
ASTM F1216 (bending stress 4,500 psi and bending modulus 250,000 psi).
B-53
-------
Table B-36. New York 2: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1300
0.1336
0.1321
0.1390
0.1284
0.1250
0.0983
0.1385
0.1392
0.1455
0.1462
0.1365
0.1345
0.1403
0.1354
Peak Load
(Ib)
450.87
500.33
465.09
572.73
486.89
461.26
475.89
502.19
505.65
580.61
535.87
454.18
467.87
491.37
479.19
459.33
39.92
Peak Stress
(psi)
3,471
3,742
3,521
4,120
3,792
3,690
4,841*
3,626
3,633
3,990
3,665
3,327
3,479
3,502
3,539
3,729
369
Tensile
Modulus
(psi)
462,521
605,810
532,143
558,672
533,626
533,729
732,320*
535,320
567,942
577,666
537,092
495,523
511,923
584,860
542,363
554,101
60,853
* Result is not within ± 25% RPD.
Flexural Stress Vs Flexural Strain
0.12
Flexural Strain, in/In
Figure B-72. New York 2: Stress - Strain Curves from Flexural Testing
B-54
-------
Table B-37. New York 2: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0074
0.0060
0.0064
0.0069
0.0071
0.0065
0.0071
0.0073
0.0071
0.0071
0.0072
0.0068
0.0073
0.0069
0.0071
Peak Load
(Ib)
56.17
37.73
46.24
49.56
60.77
52.38
59.70
61.99
57.90
60.93
59.07
58.16
57.39
55.92
59.70
55.57
6.61
Peak Stress
(psi)
7,591
6,288
7,225
7,183
8,559
8,058
8,408
8,492
8,155
8,582
8,204
8,553
7,862
8,104
8,408
7,978
654
Flexural
Modulus
(psi)
475,682
415,252
424,530
463,767
506,677
469,488
494,120
481,669
487,077
501,782
503,308
499,735
459,930
471,710
509,404
477,609
28,389
B.5.2.8 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved CIPP liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure B-73. The hardness of the surface exposed to the
flow (inner surface) was found to be slightly higher than that of the protected (outer) surface, suggesting
little, if any, softening or erosion of the resin on the inner surface of the tube during its service life. Note
that the inner surface of the liner is the resin beneath the original sealing layer which had eroded or
degraded away.
NYC 15 inch
. INNt-R • OUTER
Average ot Inner Surface 73.3 ± 3.27
Average oi Qute< Surface 72.1 * 3.60
0
I
tHrttentnivtfuir^
B! K * £ S I s" s
UTT vr-
«*, Kti
9 10 11 12 13 14 15 16 17 18 19 20
Specimen
Figure B-73. New York 2: Shore D Hardness Readings for the Liner's Inner and
Outer Surfaces
B-55
-------
B.5.2.9 Glass Transition Temperature. The calculated Tg values are summarized in Table B-38 for
the City of New York (Willoughby) sample. The average Tg for the field samples was 87.28°C (+/-
2.49°C) as measured by ASTM Method E1356-08 with DSC.
Table B-38. New York 2: Tg Determination (Willoughby CIPP Liner)
Sample
NYC
(Willoughby)
NYC
(Willoughby)
NYC
(Willoughby)
Run
1
2
3
Tg (°C)
84.43
89.05
88.36
B.5.3 New York Sample 3: A 24-Year Old CIPP Liner in a 12 in. Extra Strength Vitrified
Clay Pipe. The sample was recovered at 3rd Street, Brooklyn, New York on January 29, 2013, on the
same street as the location of Sample 1. It represented a replacement sample for the defective Sample 1.
The host pipe was at a depth of approximately 11.5 to 12 ft below ground level. Little information was
available on the CIPP characteristics for this sample beyond the year of installation which was 1988-1989
and the original installer (see Table B-39).
Table B-39. New York 3: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
15 in. Extra Strength Vitrified Clay
Pipe
7.09 mm (laboratory measurement)
Not available
Not available
Not available
Not available
Not available
1988-1989
Insituform
Not available
B.5.3.1 Visual Inspection. The retrieval process and the retrieved sample are shown in Figure B-74.
The second sample was collected from a different manhole on 3rd Street and was found to be fully cured
unlike the first defective sample.
B.5.3.2 Annular Gap. Since only the CIPP liner was received, no annular gap measurements were
possible.
B. 5.3.3 Environmental Service Conditions. No soil samples were collected because of sample
removal through the manhole.
B-56
-------
Figure B-74. New York 3: Retrieval of the Sample (left) and Retrieved Sample (right)
B.5.3.4 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The average thickness of the liner was found to be 7.09 mm ± 0.27 mm as
shown in Figure B-75. The design thickness was unavailable, therefore no comparison was made.
NYC 12 inch
6.0
5.0
0.0
_^ Average Thicknes 7.09 mm ± 0.27 mrr
SI S2 S3 S4 S5 56 S7 58 59 510 Sll S12 513 514 515 516 517 518 S19 S20
Measured specimens
Figure B-75. New York 3: Average Thickness of the Liner Sample
B.5.3.5 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D 792. The specific gravity results are shown in Figure B-76. The obtained
values were between 1.13 and 1.18. The average specific gravity was 1.15 ± 0.01.
B-57
-------
NYC 12 inch
Average 1.15 ±0.01
I
5
1.30
1.20
n nn
S
!
S — t
t — :
s
3 U
• — '
|_f
i "
1 — *
0 u
T u
^
? f
-i — '
-, I-
1 — '
| — !
H
• — s
j — ;
c
j t
i
i — "
t §
s f
I LI
i
: t
1 L
4 ,
1-!
|-|
§(i
1-
1 u
4^r
1 0
• c
! — 2
i u
4 — -
i ',
1 u
1
i
1
1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure B-76. New York 3: Measured Specific Gravity of the Liner
B. 5.3.6 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved CIPP liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. A water jet cutter could not be used as the
liner was curved and too small to be safely secured inside the cutting board.
Tensile test results are presented in Figure B-77 and Table B-40. The average tensile strength was 3,275
± 262 psi and the average tensile modulus was 324,406 ± 54,913 psi. The tensile elongation at break
varied from about 3.0% to 12%.
Tensile Modulus of Elasticity
Sample 1
Sample 7
Sample 3
Sample 4
Sample S
Sample &
Sample 7
Sample 8
Sample?)
Sample 10
—Sample 11
Sample 12
Sample 13
— Sample 14
li,im|f'<- IS
1SOO
1000
0.06 0.08
Strain, In/In
0.12
ii 1.1
Figure B-77. New York 3: Stress - Strain Curves from Tensile Testing
B-58
-------
Table B-40. New York 3: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1396
0.1200
0.1331
0.1304
0.1363
0.1237
0.1321
0.1410
0.1397
0.1422
0.1326
0.1287
0.1308
0.1368
0.1352
Peak Load
(Ib)
485.38
407.23
441.56
406.87
417.86
407.24
465.08
476.59
494.85
485.13
429.94
344.60
410.90
401.84
498.34
438.23
44.46
Peak Stress
(psi)
3,477
3,394
3,318
3,120
3,066
3,292
3,521
3,380
3,542
3,412
3,157
2,678
3,141
2,937
3,686
3,275
262
Tensile
Modulus
(psi)
322,496
320,125
291,114
335,792
199,967*
317,206
411,721
407,646
351,886
340,811
369,757
243,429
305,713
303,246
345,178
324,406
54,913
* Result is not within ± 25% RPD.
B.5.3.7 Flexural Test (ASTMD790). Specimens, as described in ASTM D790, were cut from the
retrieved CIPP liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. A water jet cutter could not be used as the
liner was curved and too small to be safely secured inside the cutting board.
Flexure test results are presented in Figure B-78 and Table B-41. All the bending stress values were
found to be above the values prescribed in ASTM F1216 (bending stress 4,500 psi). The average flexural
strength was 7,200 ± 997 psi. For the flexural modulus, the values ranged from approximately 200,000 to
373,000 psi with an average of 285,177 ± 49,221 psi, which is higher than the minimum prescribed by
ASTM F1216 (250,000 psi).
B.5.3.8 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved CIPP liner with a band
saw. A total of 400 readings were taken on the inner and outer sides of the samples. The average
recorded values are shown in Figure B-79. The data suggest that the hardness values of the liner's inner
and outer surfaces are very similar, indicating minimal degradation of the surface exposed to the flow
(i.e., inner surface) compared with the surface which was protected from the flow (outer surface). The
variation is slightly higher than for the Willoughby Street sample, but with a similar standard deviation
for both the inner and outer surfaces.
B-59
-------
Flexural Stress Vs Flexural Strain
o.oi
0.02
0.03
0.04
0.05
O.OC
0.07
0.08
0.09
Flexural Strain, In/In
Figure B-78. New York 3: Stress - Strain Curves from Flexural Testing
Table B-41. New York 3: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0069
0.0067
0.0058
0.0062
0.0065
0.0066
0.0064
0.0059
0.0060
0.0069
0.0063
0.0062
0.0064
0.0066
0.0070
Peak Load
(Ib)
36.28
48.23
37.05
37.89
46.56
43.36
44.83
47.51
55.86
43.09
45.96
48.47
51.59
50.56
55.03
46.15
5.98
Peak Stress
(psi)
5,258*
7,199
6,388
6,111
7,163
6,570
7,005
8,053
9,310*
6,245
7,295
7,818
8,061
7,661
7,861
7,200
997
Flexural
Modulus
(psi)
199,529*
246,671
249,418
229,737
284,773
260,699
286,030
361,610
373,328
258,034
266,628
345,924
322,962
303,025
289,286
285,177
49,221
* Result is not within ± 25% RPD
B-60
-------
NYC 12 inch
INNER • OUTER
Average of Inner Surface 57.7 ± 3.74
Avefafie 0( Qutef Surface 58.7 ± 3.17
6 / H 9 It) II 12 13 14 Ib 16 I/ 18 19 JO
Specimen
Figure B-79. New York 3: Shore D Hardness Readings for Inner and Outer Surfaces
B.5.3.9 Glass Transition Temperature. The calculated Tg values are summarized in Table B-42 for
the City of New York (3rd Street) sample. The average Tg for the field samples was 90.10°C (± 4.10°C)
as measured by ASTM Method E1356-08 with DSC.
Table B-42. New York 3: Tg Determination (3rd Street CIPP Liner)
Sample
NYC (3rd)
NYC (3rd)
NYC (3rd)
NYC (3rd)
Run
1
2
3
4
Tg (°C)
88.36
87.54
88.26
96.22
B.6
City of Northbrook
This section contains the test results performed on a 12 in. diameter liner exhumed from 990 Skokie
Boulevard, Northbrook, Illinois. This particular CIPP liner had been installed as part of a research and
demonstration project jointly undertaken by the Village of Northbrook and EPA between 1979 and 1981
(Driver and Olson, 1983). The actual installation of the CIPP liner took place in October 1979. The host
pipe to be rehabilitated was a 12 in. sanitary sewer installed in 1962 by a private contractor. The ground
conditions were reported to be from clay to silty loam with a frequently high water table. The average
water table was reportedly consistently 6 in. above the pipe. The depth of the host pipe was
approximately 9 ft. Prior to the CIPP lining, the line was witnessed to have considerable surcharging
events following precipitation. Also, prior to relining, the pipe was seen to have many offset and pulled
joints with visible infiltration, as well as radial and longitudinal cracks in many locations. Some sections
were considered to be structurally unstable (with sections no longer circular). The deterioration was
linked to the lack of construction inspection by the city at the time of the installation and the poor ground
conditions and high water table leading to possibly inadequate bedding of the pipe at the time of
construction. Comparisons of pre- and post-lining infiltration and flow characteristics showed significant
improvement in performance with no surcharging during wet weather events.
B-61
-------
The physical properties of the CIPP liner material were tested by an independent laboratory and are
summarized in Table B-43. However, it should be noted that the samples tested were "...flat samples of
the cured liner material which, by statement from the manufacturer (Appendix A), were of identical
materials and thickness and cured in the same manner as the Northbrook test section ... " (Driver and
Olson, 1983).
The testing of resistance to reagents comprised testing of the tensile and compressive properties of the
liner (five test samples for each reagent) after 168 hr of immersion in the following nine reagents: acetic
acid, ammonia, brine, calcium hydroxide, diesel fuel, hydrochloric acid, gasoline, nickel plating solution
and sulfuric acid. The highest average loss of tensile strength was for diesel fuel with a loss of 21% in
tensile strength. The highest average loss of compressive strength was for nickel plating solution with a
loss of 24%. Full results and solution strengths are provided in the referenced report.
In addition to the above laboratory testing, a 12 ft section of the lined pipe was dug up and removed for
further testing of the as-installed liner. A 5 ft long test section of the liner alone was cut from the
removed sample and installed in a new host pipe to allow external pressure testing. Liner deformation in
the form of local buckling was noted at around 50 psi in the test with the liner returning to its original
cross-section after the pressure was removed.
A follow-up visual inspection was carried out on March 24, 1980 with no evidence of deterioration,
infiltration, or buildup of material in the invert of the pipe noted.
Table B-43. Northbrook: Test Results at Installation
Property
Tensile strength
Tensile Modulus
Flexural Strength
Flexural Modulus
Compressive Strength
Compressive Modulus*
Coefficient of Thermal
Expansion
Shear Strength
Deformation under Load
(800 psi, 158°F, 24 hr)
Deflection Temperature
Flexural Fatigue Endurance
Limit
Bearing Strength
Resistance to Reagents
ASTM Test
Method
D-638
D-638
D-790
D-790
D-695
D-695
D-696
D-732
D-621
D-648
D-671
D-953
D-543
Insituform CIPP
5,420 psi
475,000 psi
9,320 psi
403,000 psi
15,500 psi
325,000 psi
5.96xlO-5in./in./°C
8, 150 psi
0.149%
106°C@66psi
92.5°C@264psi
1,360 psi @ 107
cycles
3,330 psi @ 4% def
5,910 psi @max.
Effect of 9 reagents
tested
* The summary table in the 1983 report substitutes the strength for this value. The values in
this table are taken from the testing company report in the appendix of the Driver and Olson
(1983) report in which this value is of the correct order of magnitude.
B-62
-------
For the current evaluation, a first attempt was made to retrieve a sample on June 5, 2013. The excavation
and pipe section removal were completed, but it was found that this particular location had not been lined.
It is possible that this was the same location of the section previously removed after CIPP installation in
1979 as described above, but historic records were not available to confirm this. The line was then
videotaped from the upstream manhole to the downstream manhole (total length ~110 ft). The pipe was
found to be lined for 32 ft starting at the upstream manhole and for approximately 5 ft starting at the
downstream manhole. A CIPP sample was then retrieved on June 11, 2013. Onsite personnel included
representatives from the Village of Northbrook and Layla Construction (contractor). A lined 6 ft section
of 12 in. clay pipe was collected.
B.6.1 Northbrook Sample 1. The host pipe and liner information are shown in Table B-44 and the
site for sample removal is shown in Figure B-80.
The retrieval process and the retrieved sample are shown in Figure B-81. The specimens were received at
the TTC South Campus Lab Facility on July 23, 2013.
B.6.1.1 Visual Inspection. The sample was in good condition, with the exception of an
approximately 0.5 in. annular gap at the 5 o'clock position of the liner.
Table B-44. Northbrook: Host Pipe and Liner Information
Host pipe
Liner Design Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Clay pipe, 12 in. diameter at approximately
6 mm (2-3 mm Felt - EPA-BOO/S2-83-064
9 ft depth
Sept. 1983)
Partially polymerized thermosetting resin
Information not available
Information not available
Densely needled polyester fiber
Polyurethane
October 1979
Insituform Technologies
Information not available
B.6.1.2 Annular Gap. The south end of the section of pipe removed was where a subsequent point
repair had been made, so that the south end of the sample had been connected to the replaced segment
with a coupling. The remnants of the connection were left intact and no measurements were made. The
north end is the upstream location. Eight readings were taken on the liner within the sample removed (at
the north end) and again on the adjacent host pipe that remained in place (see Table B-45).
B.6.1.3 Environmental Service Conditions. Waste material on the inside and outside of the sample
was collected and stored in a bottle filled with distilled water. pH was measured separately using pH-
indicator strips. pH was found to be between 6 and 7. The pH of the inside and outside was almost the
same value.
B.6.1.4 Ovality. A profile plotter was used to map any deformation inside the liner. Continuous
readings were taken around the circumference of three cross-sections spaced 8 in. apart and averaged.
B-63
-------
The liner was found to be approximately circular with reference to its center (see Figure B-82). The
ovality of the liner was found to vary from 0.33% to 0.38%. The ovality curves of all three sections were
almost the same and hence are difficult to distinguish in the plot.
Figure B-80. Northbrook: Sample Retrieval Location
Figure B-81. Northbrook: Retrieval of the Sample (left) and Received Sample (right)
Table B-45. Northbrook Annular Gap Measurements
O'Clock Position
12:00
1:30
3:00
5:00
6:00
7:30
9:00
11:00
Annular Gap Measured for
Remaining Host Pipe (north
end of sample)
0.027 in. (0.69 mm)
0.019 in. (0.48mm)
0.0 11 in. (0.28mm)
0.420 in. (10.67 mm)
0.170 in. (4.32mm)
0.008 in. (0.20 mm)
0.016 in. (0.41mm)
0.009 in. (0.23 mm)
Annular Gap Measured for
Retrieved Host Pipe Sample
(north end)
0.026 in. (0.66 mm)
0.019 in. (0.48mm)
0.010 in. (0.25mm)
0.380 in. (9.65 mm)
0.100 in. (2.54mm)
0.008 in. (0.20 mm)
0.016 in. (0.41mm)
0.008 in. (0.20 mm)
B-64
-------
Profile Plot (Northbrook)
—Hovt Pipe Top section Middle Section End Section
Figure B-82. Northbrook: Ovality of the Liner at Up Stream,
Middle Section, and Down Stream
B.6.1.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the liner specimen. The thickness was measured randomly using a micrometer with a
resolution of ±0.0025 mm. The average thickness was found to be 4.66 mm ± 0.21 mm as shown in
Figure B-83. The design thickness was 6 mm.
Northbrook 12 inch
6.2
5.2
4.2
3.2
2.2
1.2
0.2
-0.8
Design 6 mm
Average 4.66mm ±0.21 mm
SI S2 S3 54 S5 S6 S7 S8 S9 S10 Sll S12 S13 S14 S15 S16 S17 S18 S19 S20
Measured specimens
Figure B-83. Northbrook: Average Thickness of the Sample
B-65
-------
B.6.1.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values from the sample are shown in Figure B-84.
The obtained values were between 1.16 and 1.24. The average specific gravity was 1.19.
Northbrook 12 inch
Awrjlge 1.19 10.001
i.»fs~l~§~g~s 1 I 5j~l~5~i~?~! M = 3 i I
1.20 , ..—I....—...7....7...u........£...,__...-;... ,. .. ...........iji.....,..Mi...r....u
1.00
l= 0.80
0.70
O.SO
0-50
0.40
0.30
0.20
0.10
0.00
1 2 3 4 5 6 78 9 10 11 12 13 M IS 16 17 18 19 20
Number of Samples
Figure B-84. Northbrook: Measured Specific Gravity of the CIPP Liner
B.6.1.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
liner using a table saw and a band saw. Type II specimen dimensions were used for the ASTM D638
tensile test. The sides of the specimens were smoothed using a grinder. A total of 15 specimens were
prepared and tested.
The tensile test results are presented in Figure B-85 and Table B-46. The average tensile strength was
4,402 ± 175 psi. The average tensile modulus was calculated to be 433,541 ± 28,506 psi.
Tensile Modulus of Elasticity
Figure B-85. Northbrook: Stress - Strain Curves from Tensile Testing
B-66
-------
Table B-46. Northbrook: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0983
0.1005
0.0990
0.0964
0.1107
0.0094
0.1203
0.0964
0.0907
0.0894
0.0948
0.0962
0.0877
0.0907
0.0828
Peak Load
(Ib)
427.22
435.80
455.33
408.47
463.64
442.21
567.80
411.35
402.60
418.01
409.38
412.19
400.38
402.64
344.18
426.75
47.98
Peak Stress
(psi)
4,346
4,336
4,599
4,237
4,188
4,449
4,724
4,267
4,439
4,676
4,318
4,285
4,565
4,439
4,157
4,402
175
Tensile
Modulus
(psi)
411,329
402,404
397,254
414,831
458,823
495,270
425,035
418,493
413,592
478,705
442,872
410,866
451,702
437,925
444,023
433,541
28,506
B.6.1.8 Flexural Test (ASTMD790). A total of 15 specimens were prepared for ASTM D790
flexure tests. The flexure test results are presented in Figure B-86 and Table B-47. The area values were
automatically back calculated by the software when the peak load was reached. The average flexural
modulus was 322,360 ± 46,910 psi and the average flexure strength was 7,761 ± 883 psi.
Flexural Stress Vs Flexural Strain
1
Sample 7
Samples
Sample 9
Sample 10
—Sample 11
Sample 12
Sample 13
Sample 14
Sample IS
0.01 0.02 0,03 0.04 0.05
0.06
0.07
O.OB
Flexural Strain, in/in
Figure B-86. Northbrook: Stress - Strain Curves from Flexural Testing
B-67
-------
Table B-47. Northbrook: Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0033
0.0029
0.0028
0.0032
0.0030
0.0029
0.0030
0.0037
0.0030
0.0032
0.0050
0.0029
0.0028
0.0037
0.0062
Peak Load
(Ib)
25.43
23.14
24.72
26.6
28.07
21.5
24.09
27.08
23.04
24.21
42.26
22.87
20.71
23.05
38.77
26.37
6.12
Peak Stress
(psi)
7,706
7,979
8,829
8,312
9,357
7,414
8,030
7,319
7,680
7,566
8,452
7,886
7,396
6,230
6,253
7,761
833
Flexural
Modulus
(psi)
330,705
284,652
370,383
338,927
383,681
295,071
334,193
327,404
309,646
337,505
336,131
403,957
309,658
237,922*
235,557*
322,360
46,910
* Result is not within ± 25% RPD.
B.6.1.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved CIPP liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure B-87. The hardness of the surface exposed to the
flow (inner surface) was found to be only slightly lower than that of the protected (outer) surface,
suggesting little, if any, softening or erosion of the resin on the inner surface of the tube during its service
life. Differences may also be expected due to the initial presence of the sealing layer on the internal
surface.
Northbrook 12 inch DINNER • OUTER
Avenge of tt*w Hirficv 65,6 ±0.8
Average of outer surface 76.0 ± 1.0
I
I
1 1 3 4 5 6 7 8 9 10 11 12 13 14 IS 1C 17 18 19 20
Figure B-87. Northbrook: Shore D Hardness Readings from Inner and Outer Surfaces
B-68
-------
B.6.1.10 Short-Term Buckling Test. For the short-term buckling test, a 30 in. long piece of full
circumference was cut from the sample and housed inside a 14-in. diameter steel tube 30 in. in length.
The larger diameter of the steel tube ensured accommodation of any ovality and local curvature of the
liner. The large annular gap for the buckling test makes the test very conservative compared to a liner
tightly fitted within the host pipe in the field. However, the test sections also are known to be too short to
eliminate end effects (not conservative) because the host pipe configuration and overall testing program
did not permit a pipe section with a length of four to six times diameter (32 to 48 in.) to be used.
Provision was made to apply a high pressure using the TTC's EPAD. However, the liner collapsed at a
supply line water pressure of approximately 5 psi before the N2 was released to the accumulator (see
Figure B-88). The liner collapsed at close to the 11 o'clock position in the test setup which mapped to the
5 o'clock position in the liner's original field location.
Figure B-88. Northbrook: Short-Term Buckling Test
B.6.1.11 Glass Transition Temperature. The calculated Tg values are summarized in Table B-48 for
the Northbrook CIPP sample. The average Tg for the field samples was 105.74°C (± 1.29°C) as
measured by ASTM Method E1356-08 with DSC.
Table B-48. Northbrook: Tg Determination
Sample
Northbrook (Skokie)
Northbrook (Skokie)
Northbrook (Skokie)
Run
1
2
3
Tg (°C)
105.58
104.54
107.11
B.7
City of Winnipeg
This section contains the test results performed on three liner samples obtained from the City of
Winnipeg, Manitoba, Canada following its own retrospective evaluation program (see Section 4 in this
report and Macey et al., 2012, 2013). Only a limited set of tests were performed at the TTC due to the
limited sample size that was available from these previously exhumed samples. This limitation is noted
where applicable in the test results presentation below.
B-69
-------
B.7.1 Winnipeg Sample 1: A 34-Year Old CIPP Liner in a 30 in. Reinforced Concrete Pipe.
This sample was retrieved from Richard Street in the City of Winnipeg, Manitoba on December 8, 2011.
It was part of a larger sample that was tested by the City of Winnipeg. The results from that testing as
reported by Macey et al. (2012 and 2013) are presented in Sections 4 and 5. The sewer identification
location is MA20010001. The host pipe and liner information are shown in Table B-49. The host pipe
depth was reported to be 17.7 ft (5.4 m).
Table B-49. Winnipeg 1: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Reinforced concrete pipe, 30 in
. diameter
Design thickness is 6 mm
Unfilled isophthalic polyester resin
Information not available
Information not available
Information not available
Information not available
November 1978
A.B.C. Pipe Cleaning Services
Limited
Information not available
The sample (see Figure B-89) was received at the TTC South Campus Facility on August 2, 2013.
Figure B-89. Winnipeg 1: Received Sample
B. 7.1.1 Visual Inspection. The sample as received at the TTC was found to be in excellent
condition.
B. 7.1.2 Annular Gap. Since only the CIPP liner was received, no annular gap measurements were
possible.
B. 7.1.3 Environmental Service Conditions. Soil collection was not applicable because the sample
was retrieved via a manhole.
B-70
-------
B. 7.1.4 Thickness. A total of 90 readings were taken on 15 1 in. x 1 in. samples cut from different
locations of the liner specimen. The thickness was measured randomly using a micrometer with a
resolution of ±0.0025 mm. The average thickness was found to be 6.60 mm ± 0.68 mm as shown in
Figure B-90. The design thickness was 6 mm. The average installed thickness at the sample location was
10% greater than the design thickness.
Winnipeg Richard
sio sn si2 Sis sw sis
Measured specimens
Figure B-90. Winnipeg 1: Average Thickness of the Sample
B. 7.1.5 Specific Gravity. The specific gravity of the liner was measured on 15 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values from the sample are shown in Figure B-91.
The obtained values were between 1.15 and 1.30. The average specific gravity of the liner was 1.21.
Winnipeg Richard
Number of Samples
Figure B-91. Winnipeg 1: Measured Specific Gravity of the CIPP Liner
B. 7.1.6 Tensile Test (ASTMD638). No tensile testing according to ASTM D638 was possible
because of the size of the sample received at the TTC.
B-71
-------
B. 7.1.7 Flexural Test (ASTMD790). No flexural testing according to ASTM D790 was possible
because of the size of the sample received at the TTC. However, data from flexural property testing
conducted by the City of Winnipeg were provided. The data for flexural strength and flexural modulus
are shown in Table B-50. The calculated average flexural strength from the data provided is 8,592 ±321
psi and the calculated average flexural modulus is 452,134 ± 17,373 psi. These data are similar to those
published in Macey et al. (2013) for the same liner (flexural strength reported to range from 7,252 psi to
8,412 psi and the flexural modulus ranging from 448,457 psi to 455,999 psi).
Table B-50. Winnipeg 1 (Richard): Flexural Test Results
Sample ID
1
2
3
4
5
6
7
Average
St. Dev
Flexural
Strength
(psi)
8,455
8,473
8,300
8,591
8,446
9,285
8,592
8,592
321
Flexural
Modulus
(psi)
455,047
427,944
461,276
434,410
453,223
480,741
452,300
452,134
17,373
B. 7.1.8 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. A total of 300 readings were taken on the inner and outer surfaces of the
liner specimens. The average recorded hardness values are shown in Figure B-92. The hardness of the
surface exposed to the flow (inner surface) was found to be only slightly lower than that of the protected
(outer) surface, suggesting little, if any, softening or erosion of the resin on the inner surface of the tube
during its service life. Differences may also be expected due to the initial presence or any continuing
presence of the sealing layer on the internal surface.
Winnipeg Richard
Ave*«ev oflniMf Suffice w 4 t 3.07
A..-rd.y atOinvt xrl.j.. >• 65.8 t 4.1A
I I I I I I I I I I I
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Specimen
Figure B-92. Winnipeg 1: Shore D Hardness Readings from Inner and Outer Surfaces
B-72
-------
B. 7.1.9 Glass Transition Temperature. The calculated Tg values are summarized in Table B-51 for
the Winnipeg (Richard) sample. The average Tg for the field samples was 122.28°C (± 2.92°C) as
measured by ASTM Method E1356-08 with DSC.
Table B-51. Winnipeg 1: Tg Determination (Richard St. CIPP Liner)
Sample
Winnipeg (Richard)
Winnipeg (Richard)
Winnipeg (Richard)
Run
1
2
3
Tg (°C)
119.96
124.46
125.43
B.7.2 Winnipeg Sample 2: A 34-Year Old CIPP Liner in an 18 in. Vitrified Clay Pipe. This
sample was retrieved from Kingsway in the City of Winnipeg, Manitoba on December 8, 2011. It was
part of a larger sample that was tested by the City of Winnipeg. The results from that testing as published
by Macey et al. (2012 and 2013) are presented in Sections 4 and 5. The sewer identification location is
MA20010001. The host pipe and liner information are shown in Table B-52. The host pipe depth was
reported to be 12.3 ft (3.76 m).
Table B-52. Winnipeg 2: Host Pipe and Liner Information
Host pipe
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
Vitrified clay tile pipe, 1 8 in. diameter
Design thickness is 6 mm
Unfilled isophthalic polyester resin
Information not available
Information not available
Information not available
Information not available
November 1978
A.B.C. Pipe Cleaning Services Limited
Information not available
The sample (see Figure B-93) was received at the TTC South Campus Facility on August 2, 2013.
B-73
-------
Figure B-93. Winnipeg 2: Received Sample
B. 7.2.1 Visual Inspection. The sample as received at the TTC was found to be in excellent
condition. The polyurea coating was still in place and the thickness of the liner was uniform around the
circumference.
B. 7.2.2 Annular Gap. Since only the CIPP liner was received, no annular gap measurements were
possible.
B. 7.2.3 Environmental Service Conditions. Soil collection was not applicable because the sample
was retrieved via a manhole.
B. 7.2.4 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness was found to be 6.69 mm ± 0.31 mm as shown in Figure B-94. The
design thickness was 6 mm. The average installed thickness at the sample location was 11.5% greater
than the design thickness.
Winnipeg Kingsway
51 52 S3 SI 55 56 57 SB 59 510 511 512 513 514 515 516 517 518 519 520
Measured specimens
Figure B-94. Winnipeg 2: Average Thickness of the Sample
B-74
-------
B. 7.2.5 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values from the sample are shown in Figure B-95.
The obtained values were between 1.04 and 1.19. The average specific gravity of the liner was 1.14.
Winnipeg Kingsway
I
LJB
1.10
1.00
0.90
0.80
u /n
a IM
a bo
il .1(1
0.30
u.lu
(J (XI
!
i
'
!
!
i '!
? 1
t ;
J r
*
'
f
'
i Z
:
i
!
;
} \
«
:
•
-
F
5 !
>
• ?
¥
1 ? 3 4 ri G 7 R
ID tl 12 13 14 IS If. 17 18 19 Pfl
Number of Samples
Figure B-95. Winnipeg 2: Measured Specific Gravity of the CIPP Liner
B. 7.2.6 Tensile Test (ASTM D638). No tensile testing according to ASTM D638 was possible
because of the size of the sample received at the TTC.
B. 7.2. 7 Flexural Test (ASTM D790). No flexural testing according to ASTM D790 was possible
because of the size of the sample received at the TTC. However, data from flexural property testing
conducted by the City of Winnipeg were provided. The data for flexural strength and flexural modulus
are shown in Table B-53. The calculated average flexural strength from the data provided is 6,779 ±
1,346 psi and the calculated average flexural modulus is 323,930 ± 59,728 psi. These data are similar to
those published in Macey et al. (2013) for the same liner (flexural strength reported to range from 5,511
psi to 7,297 psi and the flexural modulus ranging from 272,816 psi to 375,068 psi).
Table B-53. Winnipeg 2 (Kingsway): Flexural Test Results
Sample ID
1
2
3
4
5
6
7
Average
St. Dev
Flexural
Strength
(psi)
5,938
6,316
4,856
7,868
6,672
9,027
6,779
6,779
1,346
Flexural
Modulus
(psi)
277,347
299,458
241,504
381,630
327,520
416,120
323,930
323,930
59,728
B-75
-------
B. 7.2.8 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. A total of 400 readings were taken on the inner and outer surfaces of the
liner specimens. The average recorded hardness values are shown in Figure B-96. The hardness of the
surface exposed to the flow (inner surface) was found to be only slightly lower than that of the protected
(outer) surface, suggesting little, if any, softening or erosion of the resin on the inner surface of the tube
during its service life. Differences may also be expected due to the initial presence or any continuing
presence of the sealing layer on the internal surface.
Winnipeg Kingsway DINNER BOUTER
Average of Inner Surface 54.1 ± 5.84
Average of Outer Surface 60.9 ± 1.97
75
60
45
30
15
Specimen
Figure B-96. Winnipeg 2: Shore D Hardness Readings from Inner and Outer Surfaces
B. 7.2.9 Glass Transition Temperature. The calculated Tg values are summarized in Table B-54 for
the Winnipeg (Kingsway) sample. The average Tg for the field samples was 76.72°C (± 22.63°C) as
measured by ASTM Method E1356-08 with DSC.
Table B-54. Winnipeg 2: Sample Tg Determination (Kingsway CIPP Liner)
Sample
Winnipeg (Kingsway)
Winnipeg (Kingsway)
Winnipeg (Kingsway)
Run
1
2
3
Tg (°C)
65.13
62.23
102.80
B.7.3 Winnipeg Sample 3: A 28-Year Old CIPP Liner in a 30 in. Reinforced Concrete Pipe.
This sample was retrieved from Mission St. in the City of Winnipeg, Manitoba in January 2013. It was
part of a larger sample that was tested by the City of Winnipeg. The host pipe and liner information are
shown in Table B-55. The host pipe depth was reported to be 27 ft (8.2 m).
Table B-55. Winnipeg 3 (Mission): Host Pipe and Liner Information
I Host pipe
Reinforced concrete pipe, 30 in. diameter
B-76
-------
Liner Thickness
Resin
Primary Catalyst
Secondary Catalyst
Felt
Seal
Year of Installation
Liner Vendor
Resin Supplier
About 23 mm as measured on the sample
retrieved
Unfilled isophthalic polyester resin
Information unavailable
Information unavailable
Information unavailable
Information unavailable
April 1984
Information unavailable
Information unavailable
The sample (Figure B-97) was received at the TTC south campus facility on August 2, 2013.
Figure B-97. Winnipeg 3: Received Sample
B. 7.3.1 Visual Inspection. The sample as received at the TTC was found to be in excellent
condition.
B. 7.3.2 Annular Gap. Since only the CIPP liner was received, no annular gap measurements were
possible.
B. 7.3.3 Environmental Service Conditions. Soil collection was not applicable because the sample
was retrieved via a manhole.
B. 7.3.4 Thickness. A total of 60 readings were taken on 10 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness was found to be 22.83 mm ±3.11 mm as shown in Figure B-98.
The design thickness was not available.
B-77
-------
Winnipeg MH Mission 51
25.0
I1. U
'...0
O.I)
SI 52 53 54 55 56 S/ 58
59 510
Measured specimens
Figure B-98. Winnipeg 3: Average Thickness of the Sample
B. 7.3.5 Specific Gravity. The specific gravity of the liner was measured on 10 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values from the sample are shown in Figure B-99.
The obtained values were between 1.03 and 1.11. The average specific gravity of the liner was 1.07.
Winnipeg MH Mission 51
z
a
u
I
123456789
Number of Samples
Figure B-99. Winnipeg 3: Measured Specific Gravity of the CIPP Liner
B. 7.3.6 Tensile Test (ASTMD638). No tensile testing according to ASTM D638 was possible
because of the size of the sample received at the TTC.
B-78
-------
B. 7.3.7 Flexural Test (ASTMD790). No flexural testing according to ASTM D790 was possible
because of the size of the sample received at the TTC. However, data from flexural property testing
conducted by the City of Winnipeg were provided. The data for flexural strength and flexural modulus
are shown in Table B-56. The calculated average flexural strength from the data provided is 4,469 ± 807
psi and the calculated average flexural modulus is 245,753 ± 52,540 psi. No other data for this liner could
be found in the published material from the Winnipeg testing. Both the average flexural strength and the
average flexural modulus are just below the respective current ASTM standards but it is reported in
Macey et al. (2013) that the flexural modulus requirement at the time of installation was 240,000 psi and
the average flexural modulus test results are above that requirement.
Table B-56. Winnipeg 3 (Mission): Flexural Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
Average
St. Dev
Flexural
Strength
(psi)
5,316
5,774
4,140
5,411
4,913
4,044
3,558
3,774
4,071
3,694
4,469
807
Flexural Modulus
(psi)
298,135
315,672
258,234
292,587
280,548
231,960
155,492
189,062
234,525
201,315
245,753
52,540
B. 7.3.8 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. A total of 200 readings were taken on the inner and outer surfaces of the
liner specimens. The average recorded hardness values are shown in Figure B-100. The hardness of the
surface exposed to the flow (inner surface) was found to be only slightly lower than that of the protected
(outer) surface, suggesting little, if any, softening or erosion of the resin on the inner surface of the tube
during its service life. Differences may also be expected due to the initial presence or any continuing
presence of the sealing layer on the internal surface.
B-79
-------
Winnipeg MH Mission 51 HINNER BOUTER
Average ot Inner Surface 57.3 i 3.54
of OiiTfir Surface G4.9 + 1.4R
10
Specimen
Figure B-100. Winnipeg 3: Shore D Hardness Readings from Inner and Outer Surfaces
B. 7.3.9 Glass Transition Temperature. The calculated Tg values are summarized in Table B-57 for
the Winnipeg (Mission) sample. The average Tg for the field samples was 129.24°C (±3.27°C) as
measured bv ASTM Method E1356-08 with DSC.
Table B-57. Winnipeg 3: Tg Determination (Mission CIPP Liner)
Sample
Winnipeg (Mission)
Winnipeg (Mission)
Winnipeg (Mission)
Run
1
2
3
Tg (°C)
129.12
132.57
126.03
B-80
-------
APPENDIX C
STUDIES FOR OTHER REHABILITATION
TECHNOLOGIES
-------
C.I
Fold-and-Form (PVC) Samples
C.I.I Denver Ringsby St. Sample: A 15-Year Old Fold-and-Form PVC Liner in an 8-in.
Vitrified Clay Host Pipe. This sample was retrieved on September 24, 2013 from beneath a grassy area
in a parking lot at 3333 Ringsby Ct. in Denver, Colorado. The host pipe and liner information are shown
in Table C-l. The depth to top of pipe at the upstream (southwest) end was 37 in. and at the downstream
(northeast) end was 38 in. There was no evidence of a water table above the top of the pipe at the
retrieval.
Table C-l. Denver Ringsby Ct.: Host Pipe and Liner Information
Host pipe
Liner Thickness
Liner Type
Year of Installation
Liner
Vendor/Supplier
Vitrified clay 8 in. inner
0.5 cm (using ruler) and
diameter (outer diameter 9.75 in.)
0.46 cm (using caliper) at upstream
PVC
1998
Ultraliner
C. 1.1.1 Visual Inspection. The PVC sample was retrieved with the host pipe and both were in good
condition. The liner fitted the host pipe closely around most of the circumference. The thickness was
consistent. No soil accumulation was retained on the sample when it arrived at the TTC laboratory. The
retrieved sample in the field and in the laboratory is shown in Figure C-l.
Figure C-l. Denver Ringsby Ct.: PVC Liner and Host Pipe during Retrieval (left) and at the
Laboratory (right)
C.l.1.2 Annular Gap. Annular gaps were measured at the site and the measured gaps are
shown in Table C-2.
C-l
-------
Table C-2. Denver Ringsby Ct.: Annular Gap Results
End
12:00
1:30
3:00
4:30
6:00
7:30
9:00
11:30
Annular Gap in Remaining Host pipe (mm)
Northeast
Southwest
0.8
0
0.7
0
0.25
2
0.25
0.58
0.8
0.8
0
0
0
0
0.43
0
Annular Gap of Retrieved Sample (mm)
Northeast
Southwest
1.0
N/A
0.43
N/A
0
0.70
0
0
0.88
0
0.2
0
0.3
0
0.25
0
N/A = Not Available
C.l.1.3 Environmental Service Conditions. Soil samples were not collected. Waste material (2 g)
was collected at the inside and outside surfaces of the sample and blended with 200 mL of distilled water.
The pH was measured separately using pH-indicator strips. The pH value was found to be between 6 and
7 on both sides.
C.l.1.4 Ovality. The sample's ovality was measured using software named VectorizelT. First, the
shape of the liner was traced on a piece of paper and an image of the traced liner was taken. Next, the
image file was converted to a DXF file format using the software. An 8 in. inner diameter circle (as if it
were the host-pipe's inner diameter - red line) was drawn and the DXF drawing of the liner (black line)
was positioned inside the circle (Figure C-2). Thus, the center of the liner was approximated and
diameters were measured on the liner generated using AutoCAD. Based on the maximum diameter
measured, the ovality was 1.61%, while the ovality was 1.66% when calculated based on the minimum
diameter. The higher ovality value was used as the representative value. The detailed ovality calculation
is shown in Table C-3. For all samples in Appendix C, the outer diameter and inner diameter were
measured via this method versus ASTM D2122.
Figure C-2. Denver Ringsby Ct.: Diameter of the Liner
C-2
-------
Table C-3. Denver Rigsby Ct. - Ovality Calculation
Measured
Diameter (in.)
7.7426
7.7796
7.8009
7.8593
7.9100
7.9129
7.9970
8.0000
7.9745
7.9696
7.9319
7.8553
7.8490
7.7435
7.7711
Diameter (in.)
Maximum
8.0
Minimum
7.7426
Mean
7.7
Ovality (%) Based on
Max Dia.
1.611
Min. Dia.
1.658
C.l.1.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness on the samples was measured randomly using a micrometer
with a resolution of ±0.0025 mm. The average thickness of the liner was found to be 4.17 mm ± 0.05 mm
as shown in Figure C-3. The design thickness was not available and therefore, no comparison was made.
C-3
-------
Denver PVC
4.5
Average Thickness 4.17 mm ± 0.05 mm
3.5
3.0
2.5
2.0
SI S2 S3 S4 S5 56 S7 S8 S9 S10 Sll S12 S13 S14 S15 S16 S17 S18 S19 S20
Measured specimens
Figure C-3. Denver Ringsby Ct.: Average Thickness of the Liner Sample
C.l.1.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure C-4. The obtained
values were between 1.31 and 1.35, and average specific gravity was 1.32 ± 0.01.
Denver PVC
Avutage 1.3210.01
f 1.00
1
I
0.60
0.40
0.20
1 2 3 A 5 6 7 8 9 10 11 12 13 11 15 16 17 18 19 20
Number of Samples
Figure C-4. Denver Ringsby Ct.: Measured Specific Gravity of the Liner
C.1.1.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved PVC liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the
liner was curved and too small to be mounted inside the cutting board. The tensile test results are
presented in Figure C-5 and Table C-4. The average tensile strength was 5,418 ± 547 psi and the average
tensile modulus was 288,335 ± 31,968 psi. The elongation at break of Sample 1 was found to be lower
C-4
-------
than the other samples, but no indication of cracks or deformation was found on the sample prior to the
test.
Tensile Modulus of Elasticity
/ooo
0.05
0.15 OJ
Strain, In/in
Figure C-5. Denver Ringsby Ct.: Stress - Strain Curves from Tensile Testing
Table C-4. Denver Ringsby Ct.: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1056
0.0960
0.1081
0.1013
0.0903
0.0783
0.0937
0.0895
0.1049
0.1090
0.0847
0.0957
0.0781
0.0860
0.1094
Peak Load
(Ib)
367.65
549.87
615.53
541.43
503.38
431.06
510.73
498.01
579.37
619.92
461.71
520.93
436.21
490.71
603.67
515.35
72.66
Peak Stress
(psi)
3,482
5,728
5,694
5,350
5,575
5,505
5,451
5,564
5,523
5,687
5,451
5,443
5,592
5,706
5,518
5,418
547
Tensile
Modulus
(psi)
257,766
284,532
259,008
268,382
276,596
273,272
288,645
272,648
279,990
284,205
368,913
334,849
273,541
334,426
268,257
288,335
31,968
C.l.1.8 Flexural Test (ASTMD790). Specimens, as described in ASTM D790, were cut from the
retrieved liner using a router and a band saw. A total of 15 specimens were prepared and tested. The
sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the liner
was curved and too small to be mounted inside the cutting board. The flexure test results are presented
C-5
-------
graphically in Figure C-6 and are listed in Table C-5. The average flexural modulus was 273,471 ± 8,975
psi and flexure strength was 7,790 ± 197 psi.
Flexural Stress Vs Flexural Strain
I
Lrt
I
I
Flexural Strain, in/in
Figure C-6. Denver Ringsby Ct.: Stress - Strain Curves from Flexural Testing
Table C-5. Denver Ringsby Ct.: Flexure Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0029
0.0029
0.0032
0.0031
0.0029
0.0033
0.0030
0.0031
0.0029
0.0033
0.0030
0.0033
0.0030
0.0030
0.0032
Peak Load
(Ib)
22.73
21.84
25.42
24.40
22.27
24.26
23.76
24.85
22.93
25.30
22.95
26.17
23.95
23.91
24.34
23.94
1.23
Peak Stress
(psi)
7,838
7,531
7,944
7,871
7,679
7,352
7,920
8,016
7,907
7,667
7,650
7,930
7,983
7,970
7,606
7,790
197
Flexural
Modulus
(psi)
274,955
274,586
277,838
271,132
266,527
251,228
281,238
281,521
275,189
271,606
271,214
275,063
279,494
288,927
261,543
273,471
8,975
C. 1.1.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved PVC liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure C-7. The hardness of the surface exposed to the
flow (inner surface) was found to be slightly lower than that of the protected (outer) surface.
C-6
-------
Denver PVC
•-; INNER • OUTER
Ave'«ge of inner SurJace 63.7 = 1.12
Average at Quiet Surfdce 69.4 : 1.47
2
-s
9 10 12 13 U 14 16 U 18 19 JO
Figure C-7. Denver Ringsby Ct.: Shore D Hardness Readings for the Liner's Inner
and Outer Surfaces
C. 1.1.10 Pipe Stiffness. Pipe stiffness was measured using the Universal Testing Machine (UTM)
equipped with parallel plates according to ASTM D2412. Three 6 in. long specimens were cut from the
liner using a table saw and positioned between the plates; the load was applied at 0.50 in./min (see Figure
C-8).
Figure C-8. Denver Rigsby Ct.: Parallel Plate Test
According to ASTM D2412, the deformation of the pipe was limited to 5% of the inside diameter and the
test results are presented in Table C-6. The average value was found to be 19.75 Ibf/in./in.
Table C-6. Denver Rigsby Ct.: Pipe Stiffness Test Results
Sample
1
2
3
Average
Peak Load, Ib
7.78
7.23
7.55
7.52
Pipe Stiffness at 5% Deformation of Inside
Diameter (lbf/in./in.)
20.43
18.99
19.84
19.75
C-7
-------
C.1.2 Nashville Elaine Dr. Sample: A 14-Year Old Fold-and-Form PVC Liner in an 8-in. Clay
Pipe. The sample was recovered at 542 Elaine Drive, Nashville, Tennessee on September 22, 2013. The
host pipe and liner information are shown in Table C-7. The host pipe was reported to be at depth of 4 to
5 ft below grade.
Table C-7. Nashville Elaine Dr.: Host Pipe and Liner Information
Host pipe
Liner Thickness
Liner Type
Year of Installation
Liner
Vendor/Supplier
Clay Pipe 8 in. inner diameter
Average thickness approximately 5
mm
Fold-and-form PVC
1999
Ultraliner
C. 1.2.1 Visual Inspection. The PVC sample received along with the host pipe was in good
condition. The thickness of the sample was found to be inconsistent with significant variation observed
between the maximum and minimum thickness. The retrieved samples in the field and as received at the
TTC laboratory are shown in Figure C-9.
Figure C-9. Nashville Elaine Dr.: Images of the PVC Liner Section after Retrieval (left) and
Samples Received at the TTC Lab (right)
C.l.2.2 Annular Gap. The annular gap was measured using a feeler gauge. Eight readings were
taken on each section of the liner and are provided in Table C-8.
Table C-8. Nashville Elaine Dr.: Annular Gap Measurements
Position
12:00
1:30
3:00
5:00
6:00
7:30
Gap Measured
Section 1 (in.) (mm)
0.19(4.8)
0.01 (0.3)
0.00 (0.0)
0.19(4.8)
0.11(2.8)
0.08 (2.0)
Section 2 (in.) (mm)
0.19(4.8)
0.00 (0.0)
0.05(1.3)
0.19(4.8)
0.25 (6.4)
0.25 (6.4)
C-8
-------
9:00
11:00
0.00 (0.0)
0.03 (0.8)
0.19(4.8)
0.05(1.3)
C. 1.2.3 Environmental Service Conditions. Soil samples surrounding the pipe were not collected.
Waste material (2 g) was collected on the inside and outside surfaces of the sample and blended with 200
mL of distilled water. The pH was measured separately using pH-indicator strips. The outside pH was
found to be between 6 and 7, while the pH value on the inside was approximately 5.
C.l.2.4 Ovality. The sample's ovality was measured using software as described in Section C.I. 1.4
and with the results shown in Figure C-10. Based on the maximum diameter measured, the ovality was
2.96%, while ovality was 1.30% when calculated based on the minimum diameter. The higher ovality
value was used as the representative value. The detailed ovality calculation is shown in Table C-9.
Figure C-10. Nashville Elaine Dr.: Ovality of the Liner
Table C-9. Nashville Elaine Dr.: Ovality Calculation
Measured
Diameter (in.)
7.3188
7.3987
7.4383
7.2422
Diameter (in.)
Maximum
7.4383
Minimum
7.1305
Mean
7.2246
Ovality (%) Based on
Max Dia.
2.9574
Min. Dia.
1.3027
C-9
-------
7.2090
7.1751
7.1355
7.2377
7.1386
7.1306
7.1253
7.1627
7.1995
C.l.2.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness of the liner was found to be 5.22 mm ± 0.89 mm as shown in Figure
C-l 1. The design thickness was unavailable; therefore, no comparison was made.
Nashville PVC
7.0
4.0
3.0
1.0
0.0
o n
Average Thickness 5.22 mm ± 0.89 mm
SI S2 S3 S4 S5 S6 57 S8 S9 S10 Sll S12 S13 S14 S15 S16 S17 S18 S19 S20
Measured specimens
Figure C-ll. Nashville Elaine Dr.: Average Thickness of the Liner Sample
C. 1.2.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure C-l2 and were between
0.99 and 1.34. The average specific gravity was 1.300 ± 0.08.
C-10
-------
Nashville PVC
IM
* 100
| 0.
0.60
nnn
V
r
;
: E
• ^
! E
<
: i
I
!
•;
i- J
| i
i (
?
! — S
|
j— :
*
f c
1 1
i r
•< T
r
•• T
_]
'
I
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure C-12. Nashville Elaine Dr.: Specific Gravity of the Liner
C.1.2.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved PVC liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the
liner was curved and too small to be mounted inside the cutting board. The tensile test results are
presented in Figure C-13 and Table C-10. The average tensile strength was 5,913 ± 163 psi and the
average tensile modulus was 314,872 ± 36,523 psi.
Tensile Modulus of Elasticity
0.2 075 0.3
Strain, In/In
Figure C-13. Nashville Elaine Dr.: Stress - Strain Curves from Tensile Testing
Table C-10. Nashville Elaine Dr.: Tensile Test Results
C-ll
-------
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1264
0.1145
0.0875
0.1149
0.1200
0.1278
0.1067
0.1173
0.1174
0.1161
0.0899
0.1265
0.1119
0.1153
0.1188
Peak Load
(Ib)
726.19
687.32
515.71
664.57
699.05
719.00
655.71
706.57
682.44
721.77
536.30
731.97
662.63
674.58
725.43
673.95
65.22
Peak Stress
(psi)
5,745
6,003
5,894
5,784
5,825
5,626
6,145
6,024
5,813
6,217
5,966
5,786
5,922
5,851
6,106
5,913
163
Tensile
Modulus
(psi)
295,908
307,449
314,070
270,931
297,786
268,928
308,754
307,614
342,202
303,730
423,667
297,442
314,982
331,006
338,622
314,872
36,523
C. 1.2.8 Flexural Test (ASTMD790). Specimens, as described in ASTM D790, were cut from the
retrieved liner using a router and a band saw. A total of 15 specimens were prepared and tested. The
sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the liner
was curved and too small to be mounted inside the cutting board. The flexure test results are presented
graphically in Figure C-14 and are listed in Table C-l 1. The average flexural modulus was 279,550 ±
8,260 psi and the average flexural strength was 8,581 ± 299 psi.
Flexural Stress Vs Flexural Strain
Flexural Strain, in/in
Figure C-14. Nashville Elaine Dr.: Stress - Strain Curves from Flexural Testing
Table C-ll. Nashville Elaine Dr.: Flexure Test Results
C-12
-------
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0043
0.0039
0.0048
0.0049
0.0042
0.0044
0.0048
0.0033
0.0047
0.0048
0.0036
0.0041
0.0048
0.0045
0.0032
Peak Load
(Ib)
37.41
32.84
41.92
41.96
36.30
39.26
42.35
28.47
41.96
42.79
30.80
34.01
37.96
36.42
27.49
36.80
5.14
Peak Stress
(psi)
8,700
8,421
8,733
8,563
8,643
8,923
8,823
8,627
8,928
8,915
8,556
8,295
7,908
8,093
8,591
8,581
299
Flexural
Modulus
(psi)
273,235
273,225
276,654
269,910
275,847
282,966
298,603
288,207
283,139
284,201
290,102
273,222
272,615
270,851
280,484
279,550
8,260
C. 1.2.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved PVC liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure C-15. The hardness of the surface exposed to the
flow (inner surface) was found to be slightly lower than that of the protected (outer) surface.
Nashville PVC
: INNER BOUTER
Average of Inner Surface 64.2 ± 1.44
Average of Outer Surface 69.7 ± 1.96
Q
HI
60
30
15
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10 11 12 13
15 16 17 18
Specimen
Figure C-15. Nashville Elaine Dr.: Shore D Hardness Readings for the Liner's
Inner and Outer Surfaces
C-13
-------
C. 1.2.10 Pipe Stiffness. Pipe stiffness was measured using the UTM equipped with parallel plates
according to ASTM D2412. Three 6 in. long specimens were cut from the liner using a table saw and
positioned in between the plates; the load was applied at 0.50 in./min.
According to ASTM D2412, the deformation of the pipe was limited to 5% of the inside diameter and the
test results are presented in Table C-12. The average value was found to be 35.1 Ibf/in./in.
Table C-12. Nashville Elaine Dr.: Pipe Stiffness Test Results
Sample
1
2
3
Average
Peak Load, Ib
11.72
12.23
13.96
12.63
Pipe Stiffness at 5% Deformation of Inside
Diameter (lbf/in./in.)
32.55
33.94
38.74
35.08
C-14
-------
C.2
Deform-Reform (HOPE) Samples
C.2.1 Denver Irving St. Sample: A 15-Year Old Deform-Reform HOPE Liner in an 8 in.
Vitrified Clay Pipe. The sample was recovered at the west end of the alley running between Irving St.
and Grove St. and located between Clyde PI. and 37th Ave., Denver, Colorado on September 25, 2013.
The host pipe and liner information are shown in Table C-13. The invert of the host pipe was at a depth
of approximately 11 ft below ground level. There was no evidence of a water table above the top of the
pipe at the retrieval time but some water was accumulating in the bottom of the pit during the uncovering
of the pipe and preparation of the sample for removal.
Table C-13. Denver Irving St.: Host Pipe and Liner Information
Host pipe
Liner Thickness
Liner Type
Year of Installation
Liner
Vendor/Supplier
Vitrified clay pipe 8 in. inner
measured due to cracking)
diameter (outer diameter not
Approximately 8 mm
Deform-reform HOPE
1998
Hydro Conduit Corporation
C.2.1.1 Visual Inspection. The HOPE sample was retrieved along with the host pipe which was
badly cracked. The reasons for the cracking could not be determined. The main possibilities were that
the pipe was cracked prior to its relining in 1998 or that the pipe was cracked by the internal pressure used
to re-round the HOPE liner during its installation. There was no soil remaining on the samples when
received at the TTC laboratory. The retrieved samples are shown in the field and as received at the TTC
laboratory in Figure C-16.
Figure C-16. Denver Irving St.: Images of the HOPE Liner Section during Retrieval (left) and in
the TTC Laboratory (right)
C.2.1.2 Annular Gap. Annular gaps were not measured due to the cracking of the host pipe.
C.2.1.3 Environmental Service Conditions. No soil or residues were available for pH determination.
C-15
-------
C.2.1.4 Ovality. The sample's ovality was measured using software as described in Section C. 1.1.4
and illustrated in Figure C-17. Based on the maximum diameter measured, ovality was 3.26%, while the
ovality was 5.20% when calculated based on the minimum diameter. The higher ovality value was used
as the representative value. The detailed ovality calculation is shown in Table C-14.
Figure C-17. Denver Irving St.: Ovality of the Liner
Table C-14. Denver Irving St.: Ovality Calculation
Measured
Diameter (in.)
7.7558
7.8761
7.3690
7.2310
7.5213
7.8734
7.7790
7.7563
7.5914
7.2993
7.5981
Diameter (in.)
Maximum
7.8761
Minimum
7.2310
Mean
7.63
Ovality (%) Based on
Max Dia.
3.263
Min. Dia.
5.195
C-16
-------
I 7.8761 | | | | |
C.2.1.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness of the liner was found to be 7.98 mm ± 0.25 mm as shown in Figure
C-18. The design thickness was unavailable; therefore, no comparison was made.
Denver HOPE
AvtuBL- TMEfanm 7.«! am. t 0.15 rr
S6 S? S8 S9 S10 Sll SJ3 SI3 Sid SIS
51 a
$19 S2D
Measured specimens
Figure C-18. Denver Irving St.: Average Thickness of the Liner Sample
C.2.1.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure C-19. The obtained
values were between 0.93 and 0.95. The average specific gravity was 0.94 ±0.01.
Denver HOPE
Average 0.94 ± 0.01
n nn
i
i
i c
3 C
i <-
-1 C
:> c
:• c
i c
j c
3 C
> C
i c
3 c
> c
i c
' c
5 c
i c
i c
D
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure C-19. Denver Irving St.: Specific Gravity of the Liner
C-17
-------
C.2.1.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved HDPE liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the
liner was curved and too small to be mounted inside the cutting board. The tensile test results are
presented in Figure C-20 and Table C-15. The average tensile strength was 3,019 ± 403 psi and the
average tensile modulus was 145,851 ± 15,144 psi. The elongation at the break of Sample 1 is much
smaller than for the others. The reason is unknown as there was no evidence of a crack found on the
sample. The test period of Sample 3 was cut short due to a required response to a fire alarm in the
laboratory.
Tensile Modulus of Elasticity
0.4 0.5
Strain, In/In
Figure C-20. Denver Irving St.: Stress - Strain Curves from Tensile Testing
Table C-15. Denver Irving St.: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Area
(in.2)
0.1479
0.1565
0.1292
0.1655
0.1417
0.1661
0.1629
0.1626
0.1635
0.1642
0.1550
0.1561
0.1589
0.1678
Peak Load
(Ib)
274.61
466.91
503.55
524.54
443.21
498.08
503.19
482.87
494.43
482.21
480.45
459.16
469.70
494.23
Peak Stress
(psi)
1,857
2,983
3,897
3,169
3,128
2,999
3,089
2,970
3,024
2,937
3,100
2,941
2,956
2,945
Tensile Modulus
(psi)
149,738
144,522
156,627
106,216
128,669
138,613
154,101
167,034
151,868
142,458
160,449
142,756
139,961
141,145
C-18
-------
15
Average
St. Dev
0.1473
485.32
470.83
57.84
3,295
3,019
403
163,611
145,851
15,144
C. 2.1.8 Flexural Test (ASTM D 790). Specimens, as described in ASTM D790, were cut from the
retrieved liner using a router and a band saw. A total of 15 specimens were prepared and tested. The
sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the liner
was curved and too small to be mounted inside the cutting board. The flexure test results are presented
graphically in Figure C-21 and are listed in Table C-16. The average flexural modulus was 108,815±
5,891 psi and the average flexure strength was 3,363 ± 193 psi.
Flexural Stress Vs Flexural Strain
Sample!
Sampled
— Sim pie 3
— Sam pip 4
Sampled
Sample 6
Sample?
—Samples
Sample 9
Sample 10
Sample 11
Sample 13
— Sample 13
Sample 14
Sample 15
Flexural Strain, In/In
Figure C-21. Denver Irving St.: Stress - Strain Curves from Flexural Testing
Table C-16. Denver Irving St.: Flexure Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
Area
(in.2)
0.0092
0.0085
0.0093
0.0097
0.0091
0.0092
0.0083
0.0088
0.0099
0.0092
0.0093
0.0096
0.0088
0.0093
0.0091
Peak Load
(Ib)
31.06
32.92
33.88
33.52
29.81
31.00
28.35
30.31
33.37
29.73
30.10
30.61
27.94
29.34
29.48
30.76
Peak Stress
(psi)
3,376
3,873
3,643
3,456
3,276
3,370
3,416
3,444
3,371
3,232
3,237
3,189
3,175
3,155
3,240
3,363
Flexural
Modulus
(psi)
116,697
119,461
107,377
116,521
113,016
106,391
109,774
111,352
107,793
97,560
102,056
103,655
104,785
107,654
108,143
108,815
C-19
-------
| St. Dev
1.87
193
5,891 |
C.2.1.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved HDPE liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure C-22. The hardness of the surface exposed to the
flow (inner surface) was found to be slightly lower than that of the protected (outer) surface.
Denver HDPE
LINNFK
I Oil UK
AvL-ugc of Inner Suifucv bb.9 t l.bf
Awra«e ol Ouwt SurfKe 59.5 11.16
£
•i
30
« K
a
Figure C-22. Denver Irving St.: Shore D Hardness Readings for the Liner's Inner and Outer
Surfaces
C.2.1.10 Pipe Stiffness. Pipe stiffness was measured using the UTM equipped with parallel plates
according to ASTM D2412. Three 6 in. long specimens were cut from the liner using a table saw and
positioned in between the plates; the load was applied at 0.50 in./min. According to ASTM D2412, the
deformation of the pipe was limited to 5% of the inside diameter and the test results are presented in
Table C-17. The average value was found to be 36.5 Ibf/in./in.
Table C-17. Denver Irving St.: Pipe Stiffness Test Results
Sample
1
2
3
Average
Peak Load, Ib
14.18
14.55
13.41
14.05
Pipe Stiffness at 5% Deformation of Inside
Diameter (lbf/in./in.)
36.87
37.84
34.87
36.53
C.2.1.11 ESCR Testing. Ten specimens each 1.5 in. long, 0.5 in. wide and 0.0775 in. thick were cut
from the liner following the condition "C" mentioned in ASTM D1693. This low thickness was achieved
by placing the specimen on a belt sander. A notch of 0.015 in. was grooved in the middle of the specimen
using a specific pressing tool. Next, all specimens were bent and slid into a holder. The holder with all of
C-20
-------
the specimens was submerged in reagent (Igepal CO-630) in a test tube and the test tube was kept in an
oven at 212°F for 8 days (192 hr) (see Figure C-23) as per the requirement from ASTM D3350.
Figure C-23. Preparation of Test Specimen (left) and Specimens Inside the Oven (right)
Later, the specimens were taken out of the test tube and checked for any cracks visible by the naked eye.
No cracks were found and the sample passed the limitation of maximum failure percent of 20% as per the
standard ASTM D3350 (see Figure C-24).
Figure C-24. Specimens after the Test
C.2.2 Miami 114th St Sample: A 15-Year Old Deform-Reform HOPE Liner in an 8 in. Clay
Pipe. The sample was recovered at Basin 698 between MH#93 and MH#94 at SW 114th Court Cross
Street and SW 207th Drive, Miami, Florida on May 15, 2013. The host pipe and liner information are
provided in Table C-18. The host pipe depth was approximately 4 to 5 ft.
Table C-18. Miami 114th St.: Host Pipe and Liner Information
Host pipe
Liner Thickness
Liner Type
Year of Installation
Liner
Vendor/Supplier
Clay pipe 8 in.
Approximately 8 mm
Deform-reform HOPE
1998
Unknown
C-21
-------
C.2.2.1 Visual Inspection. The HDPE sample was found in good condition. No cracks were visible
on the pipe. There was no remaining soil accumulation on the samples when received at the TTC
laboratory. The retrieved samples are shown in Figure C-25 in the field and prior to testing.
Figure C-25. Miami 114th St.: Images of the HDPE Liner Section in the Field (Left) and Prior to
Testing (Right)
C.2.2.2 Annular Gap. Annular gaps were measured at the site after the sample was exhumed
and were recorded as 0.50 in. (12.7 mm) at the 12:00 position and 1 in. (25 mm) at the 1:30
position. However, the cracking and distortion of the host pipe that can be seen in Figure C-25
indicate that the measured values may not be meaningful. The sample was received at TTC
without any host pipe attached to it and therefore, no annular readings were recorded.
C.2.2.3 Environmental Service Conditions. External soil samples were not collected for this sample.
Waste material (2 g) from the inside of the sample was collected and blended with 200 mL of distilled
water for a pH measurement. The pH value was found to be between 7 and 8. No materials were
collected at the outer side of the sample.
C.2.2.4 Ovality. The sample's ovality was measured using software as described in Section C. 1.1.4.
The maximum diameter measured ovality was 6.66%, while ovality was 5.82% when calculated based on
the minimum diameter. The higher ovality value was used as the representative value. The tracing of the
inner circumference of the liner and the resulting diameter measurements are shown in Figure C-26. The
detailed ovality calculation is shown in Table C-19.
C-22
-------
Figure C-26. Miami 114th St.: Tracing the Liner Shape (Left) and Ovality of the Liner (Right)
Table C-19. Miami 114th St.: Ovality Calculation
Measured
Diameter (in.)
7.2676
7.3552
7.2681
6.8869
6.6747
6.5754
6.4947
6.5020
6.6594
6.8642
7.0301
7.1743
Diameter (in.)
Maximum
7.3552
Minimum
6.4947
Mean
6.90
Ovality (%) Based on
Max Dia.
6.657
Min. Dia.
5.82
C.2.2.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness of the liner was found to be 8.33 mm ± 0.11 mm as shown in Figure
C-27. The design thickness was unavailable; therefore, no comparison was made.
C-23
-------
Miami
£
i
i
9.0
8.5
7.0
6.0
5.5
Average Thickness 8.33 mm ± 0.11 mm
5.0
SI S2 S3 S4 S5 56 S7 S8 S9 S10 Sll S12 S13 S14 S15 S16 S17 S18 S19 S20
Measured specimens
Figure C-27. Miami 114th St.: Average Thickness of the Liner Sample
C.2.2.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure C-28. The obtained
values were between 0.91 and 0.95. The average specific gravity was 0.94 ±0.01.
Miami
Average 0.94 ± 0.01
'o
01
0.90
0.70
0.60
0.50
0.40
0.20
0.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure C-28. Miami 114th St.: Specific Gravity of the Liner
C.2.2.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved HDPE liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the
liner was curved and too small to be mounted inside the cutting board. The tensile test results are
C-24
-------
presented in Figure C-29 and Table C-20. The average tensile strength was 3,053 ± 92 psi and the
average tensile modulus was 142,479 ± 15,583 psi. The elongation at break varied from around 24% to
more than 70%.
Tensile Modulus of Elasticity
3000
2500
1000
500
0.4
Strain, in/in
Figure C-29. Miami 114th St.: Stress - Strain Curves from Tensile Testing
Table C-20. Miami 114th St.: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1653
0.1608
0.1725
0.1705
0.1762
0.1645
0.1502
0.1600
0.1557
0.1529
0.1553
0.1574
0.1571
0.1581
0.1512
Peak Load
(Ib)
505.99
489.33
514.50
506.79
515.34
488.76
462.28
494.37
491.17
463.98
461.87
480.93
472.64
499.50
496.40
485.59
18.03
Peak Stress
(psi)
3,061
3,043
2,983
2,972
2,925
2,973
3,078
3,090
3,155
3,035
2,974
3,055
3,009
3,159
3,283
3,053
92
Tensile
Modulus
(psi)
164,971
156,995
161,175
144,332
154,240
125,518
156,063
154,000
131,150
150,076
129,141
126,534
116,614
125,219
141,166
142,479
15,583
C-25
-------
C.2.2.8 Flexural Test (ASTMD790). Specimens, as described in ASTM D790, were cut from the
retrieved liner using a router and a band saw. A total of 15 specimens were prepared and tested. The
sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the liner
was curved and too small to be mounted inside the cutting board. The flexure test results are presented
graphically in Figure C-30 and are listed in Table C-21. The area values (Column 2 of Table C-21) were
automatically back calculated by the software when the peak load was reached. The average flexural
modulus was 103,645 ± 4,015 psi and the average flexure strength was 3,154 ± 113psi.
Flexural Stress Vs Flexural Strain
I
0,(M
Flexural Strain, in/in
Figure C-30. Miami 114th St.: Stress - Strain Curves from Flexural Testing
Table C-21. Miami 114th St.: Flexure Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0079
0.0083
0.0088
0.0087
0.0089
0.0100
0.0100
0.0100
0.0096
0.0102
0.0103
0.0102
0.0100
0.0103
0.0098
Peak Load
(Ib)
26.42
26.10
28.29
28.07
28.75
31.85
29.29
31.43
30.17
31.69
30.68
32.35
32.19
33.72
29.42
30.03
2.24
Peak Stress
(psi)
3,344
3,145
3,215
3,226
3,230
3,185
2,929
3,143
3,143
3,107
2,979
3,172
3,219
3,274
3,002
3,154
113
Flexural
Modulus
(psi)
106,983
95,692
101,799
110,277
103,045
107,648
96,785
105,118
100,583
106,432
100,786
106,738
105,333
104,230
103,234
103,645
4,015
C-26
-------
C.2.2.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved polyethylene liner with
a band saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens.
The average recorded hardness values are shown in Figure C-31. The hardness of the surface exposed to
the flow (inner surface) was found to be slightly lower than that of the protected (outer) surface.
Miami
UINNER
: OUTER
Average of Inner Surface 54.0 ± 2.69
Average of Outer Surface 56.0 ± 1.99
60
45 I
O
~
(U
ig
_
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Specimen
16
17
i
CO r
•* G
U1 u
18
H
i
1
o r
f-i U
19
si
3
1
L
20
15
Figure C-31. Miami 114th St.: Shore D Hardness Readings for the Liner's Inner and Outer
Surfaces
C.2.2.10 Pipe Stiffness. Pipe stiffness was measured using the UTM equipped with parallel plates
according to ASTM D2412. Three 6 in. long specimens were cut from the liner using a table saw; the
load was applied at 0.50 in./min. According to ASTM D2412, the deformation of the pipe was limited to
5% of the inside diameter. The test results are shown in Table C-22. The average stiffness was found to
be43.11bf/in./in.
Table C-22. Miami 114th Street: Pipe Stiffness Test Results
Sample
1
2
3
Average
Peak Load, Ib
16.00
15.40
15.17
15.52
Pipe Stiffness at 5% Deformation of Inside
Diameter (lbf/in./in.)
44.38
42.70
42.07
43.05
C.2.2.11 ESCR Testing. Ten specimens each 1.5 in. long, 0.5 in. wide and 0.0775 in. thick were
cut from the liner following the condition "C" mentioned in ASTM D1693. This low thickness was
achieved by placing the specimen on a belt sander. A notch of 0.015 in. was grooved in the middle of the
specimen using a specific pressing tool. Next, all specimens were bent and slid into a holder. Later, the
holder with all of the specimens was submerged in the reagent (Igepal CO-630) in a test tube (see Figure
C-32) and the test tube was kept in an oven at 212°F for 8 days (192 hr) as per the requirement from
ASTMD3350.
C-27
-------
Figure C-32. Specimens inside the Reagent
Following the test period, the specimens were taken out of the test tube and checked for any cracks visible
by the naked eye. No cracks were found and the sample passed the limitation of maximum failure percent
of 20% as per ASTM D3350 (see Figure C-33).
Figure C-33. Specimens after the Test
C.2.3 Nashville Danby Dr. Sample: A 19-Year Old Deform-Reform HOPE Liner in an 8 in.
Concrete Pipe. The sample was recovered at 4828 Danby Drive, Nashville, Tennessee on September 22,
2013. The host pipe and liner information are shown in Table C-23. The host pipe was reported to be at
depth of 4 to 5 ft below grade.
Table C-23. Nashville Danby Dr.: Host Pipe and Liner Information
Host pipe
Liner Thickness
Liner Type
Year of Installation
Liner Vendor/
Supplier
Concrete Pipe 8 in. inner diameter
Approximately 7 mm
Deform-reform HDPE
1994
Not known
C-28
-------
C.2.3.1 Visual Inspection. The HDPE sample with the host pipe was found in good condition. The
retrieved sample is shown in Figure C-34.
Figure C-34. Nashville Danby Dr.: Images of the HDPE Liner Section after Retrieval (left) and
Taken in the TTC Laboratory (right)
C.2.3.2 Annular Gap. The annular gap was measured using a feeler gauge. Eight readings were
taken on each section of the liner and are shown in Table C-24. Readings taken at Section 2 may not be
representative because that end of the host pipe was broken.
C.2.3.3 Environmental Service Conditions. Soil samples were not collected. Waste material (2 g)
was collected on the inside and outside of the sample and blended with 200 mL of distilled water to make
the pH measurement. The outside pH was found to be 6 to 7 while the inside pH was slightly lower at 5
to 6.
C.2.3.4 Ovality. The sample's ovality was measured
using software as described in Section C. 1.1.4. The maximum diameter measured ovality was 6.12%,
while ovality was 6.68% when calculated based on the minimum diameter. The higher ovality value was
used as the representative value. The diameter measurements are shown in Figure C-35. The detailed
ovality calculation is shown in Table C-25.
Table C-24. Nashville Danby Dr. Annular Gap Measurement
Location
12:00
1:30
3:00
5:00
6:00
7:30
9:00
11:00
Gap Measured on
Section 1 (in.) (mm)
0.03 (0.8)
0.44(11.2)
0.17(4.3)
0.08 (2.0)
0.19(4.8)
0.00 (0.0)
0.09 (2.3)
0.09 (2.3)
Section 2 (in.) (mm)
0.13(3.3)
0.06(1.5)
0.06(1.5)
N/A
0.44(11.2)
0.50(12.7)
0.50(12.7)
0.50(12.7)
N/A = Not Available
C-29
-------
Figure C-35. Nashville Dan by Dr.: Ovality of the Liner
C.2.3.4 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness of the liner was found to be 6.85 mm ± 0.03 mm as shown in Figure
C-36. The design thickness was unavailable; therefore, no comparison was made.
Table C-25. Nashville Danby Dr.: Ovality Calculation
Measured
Diameter (in.)
7.3881
7.5243
7.4839
7.0018
6.7703
6.6289
7.1501
7.4148
7.3332
6.9010
6.6168
6.8725
Diameter (in.)
Maximum
7.5243
Minimum
6.6168
Mean
7.09
Ovality (%) Based on
Max Dia.
6.118
Min. Dia.
6.68
C-30
-------
Nashville HOPE
70
6.8 "
6.6
6.4
6.2
6.0
5.8
S.6
5.4
S.2
S.O
Average Thickness 6.H?> mm * 0.01 n
I ! 1
i!!1
[ I
til
SI 52 53 54 55 56 S7 58 59 510 511 512 513 514 515 516 517 518 519 520
Measured specimens
Figure C-36. Nashville Danby Dr.: Average Thickness of the Liner Sample
C.2.3.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure C-37. The obtained
values were between 0.93 and 0.96. The average specific gravity was 0.94 ± 0.01.
Nashville HOPE
AVCMB1' 0.94 10.01
1.00
0.90
£• 08°
5 0.70
£ 0.60
f 0.50
0.40
OJO
O.JO
0.10
0.00
dodo
1234567
9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure C-37. Nashville Danby Dr.: Specific Gravity of the Liner
C.2.3.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved HDPE liner using a router and a band saw. A total of 15 specimens were prepared and tested.
The sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the
liner was curved and too small to be mounted inside the cutting board. The tensile test results are
presented in Figure C-38 and Table C-26. The average tensile strength was 2,974 ± 149 psi and the
average tensile modulus was 162,567 ± 19,705 psi. The elongation at the break of Samples 5 and 8 was
C-31
-------
found to be lower in comparison to the other samples, but the reason is unknown since no weak point or
area was found on the sample prior to the test.
Tensile Modulus of Elasticity
Strain, In/In
Sample
Simple
S»mple
S»mpl»
Sample
Sample
Sample
Sample
iimplt
SamplHO
Sample 11
Simple 13
S»mplel3
Simple 14
Sample 15
Figure C-38. Nashville Danby Dr.: Stress - Strain Curves from Tensile Testing
Table C-26. Nashville Danby Dr.: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1512
0.1503
0.1526
0.1625
0.1442
0.1473
0.1412
0.1377
0.1397
0.1543
0.1493
0.1385
0.1444
0.1469
0.1438
Peak Load
(Ib)
462.69
453.32
456.92
484.83
396.53
455.11
430.34
398.05
432.07
473.26
401.17
371.95
445.87
454.29
442.20
437.24
32.07
Peak Stress
(psi)
3,060
3,016
2,994
2,984
2,750
3,090
3,048
2,891
3,093
3,067
2,687
2,686
3,088
3,093
3,075
2,974
149
Tensile
Modulus
(psi)
164,985
228,167
168,306
153,415
150,754
153,601
169,333
149,343
166,247
165,247
162,792
144,757
152,842
155,418
153,300
162,567
19,705
C.2.3.8 Flexural Test (ASTMD790). Specimens, as described in ASTM D790, were cut from the
retrieved liner using a router and a band saw. A total of 15 specimens were prepared and tested. The
sides of the specimens were smoothed using a grinder. A water jet cutter could not be used as the liner
was curved and too small to be mounted inside the cutting board. The flexure test results are presented
C-32
-------
graphically in Figure C-39 and are listed in Table C-27. The area values (Column 2 of Table C-27) were
automatically back calculated by the software when the peak load was reached. The average flexural
modulus was 108,126 ± 3,386 psi and the average flexural strength was 3,133 ± 75 psi.
Flexural Stress Vs Flexural Strain
woo
a
Flexural Strain, In/In
Figure C-39. Nashville Danby Dr.: Stress - Strain Curves from Flexural Testing
Table C-27. Nashville Danby Dr.: Flexure Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0072
0.0068
0.0068
0.0071
0.0071
0.0072
0.0068
0.0067
0.0073
0.0072
0.0068
0.0070
0.0067
0.0071
0.0067
Peak Load
(Ib)
22.37
22.50
21.73
21.72
22.07
22.90
20.83
20.75
22.69
22.80
22.00
21.85
20.88
22.12
20.18
21.83
0.83
Peak Stress
(psi)
3,107
3,309
3,196
3,059
3,108
3,181
3,063
3,097
3,108
3,167
3,235
3,121
3,116
3,115
3,012
3,133
75
Flexural
Modulus
(psi)
111,438
115,114
109,535
104,180
106,290
107,101
105,852
106,318
106,001
113,377
110,866
107,794
108,622
106,530
102,867
108,126
3,385
C.2.3.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved HDPE liner with a band
saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens. The
average recorded hardness values are shown in Figure C-40. The hardness of the surface exposed to the
flow (inner surface) was found to be slightly lower than that of the protected (outer) surface.
C-33
-------
Nashville HOPE JINNLH
Average of Inrwr Surface °>i.b ! o.^b
Ai.-.-lrtK-' oid.Jf'-' '.,.ll.-,.-<- VI.f • II'J
»s
17 18 19 20
Figure C-40. Nashville Danby Dr.: Shore D Hardness Readings for the Liner's Inner and Outer
Surfaces
C.2.3.10 Pipe Stiffness. Pipe stiffness was measured using the UTM equipped with parallel plates
according to ASTM D2412. Three 6 in. long specimens were cut from the liner using a table saw; the
load was applied at 0.50 in./min. According to ASTM D2412, the deformation of the pipe was limited to
5% of the inside diameter. The test results are shown in Table C-28. The average value was found to be
31.31bf/in./in.
Table C-28. Nashville Danby Dr.: Pipe Stiffness Test Results
Sample
1
2
3
Average
Peak Load, Ib
12.84
10.83
11.08
11.58
Pipe Stiffness at 5% Deformation of Inside
Diameter (lbf/in./in.)
34.68
29.25
29.92
31.28
C.2.3.11 ESCR Testing. Ten specimens each 1.5 in. long, 0.5 in. wide and 0.0775 in. thick were cut
from the liner following the condition "C" mentioned in ASTM D1693. This low thickness was achieved
by placing the specimen on a belt sander. A notch of 0.015 in. was grooved in the middle of the specimen
using a specific pressing tool. All specimens were bent and slid into a holder. Later, the holder with all
the specimens was submerged in reagent (Igepal CO-630) in a test tube and the test tube was kept in an
oven at 212°F for 8 days (192 hr) (Figure C-41) as per the requirement from ASTM D3350.
C-34
-------
Figure C-41. Igepal CO-630 Reagent (left) and Specimens inside the Oven (right)
Later, the specimens were taken out of the test tube and checked for any cracks visible by the naked eye.
No cracks were found and the sample passed the limitation of maximum failure percent of 20% as per
ASTM D3350 (Figure C-42).
Figure C-42. Specimens after the Test
C.3
Sliplining (Polyethylene Pipe) Samples
C.3.1 Houston Greiner Dr. Sample: An 18-year Old Green Polyethylene Sliplined in an 8 in.
Non-reinforced Concrete Pipe. The sample was recovered between manholes 63 and 64 on Greiner
Drive, Houston, Texas on March 14, 2013. The host pipe and liner information are shown in Table C-29.
Field information was not available for this liner.
Table C-29. Houston Greiner Dr.: Host Pipe and Liner Information
Host pipe
Liner Thickness
Liner Type
Year of Installation
Liner
Vendor/Supplier
Non-reinforced concrete pipe 8 in.
0.30 inch
Slipliner using green
colored polyethylene
pipe
1995
Unknown
C-35
-------
C.3.1.1 Visual Inspection. The polyethylene sample came in good condition and the thickness was
constant along the length and circumference of the sample. The sample as received at the TTC laboratory
is shown in Figure C-43.
Figure C-43. Houston Greiner Dr.: Image of the PE Liner Section at the TTC Laboratory
C.3.1.2 Annular Gap. The sample was received without the host pipe and no annular
measurement was recorded and received from the site.
C.3.1.3 Environmental Service Conditions. Soil samples were not collected. Waste material (2 g)
was collected at the inside of the sample and blended with 200 mL of distilled water for the pH
measurement. The pH was found to be approximately 8 to 8.5. No measurement was possible for the
outside of the sample.
C.3.1.4 Ovality. The sample's ovality was measured using software as described in Section C. 1.1.4.
The resulting diameter measurements are shown in Figure C-44. The detailed ovality calculation is
shown in Table C-30. Based on the maximum diameter measured, the ovality was 1.72%, while the
ovality was 1.76% when calculated based on the minimum diameter. The higher ovality value was used
as the representative value.
C-36
-------
Figure C-44. Houston Greiner Dr.: Ovality of the Liner
Table C-30. Houston Greiner Dr.: Ovality Calculation
Measured
Diameter (in.)
7.8858
7.7755
7.7357
7.7078
7.6865
7.6912
7.6787
7.8114
7.8776
7.9257
7.9506
7.9375
7.9448
Diameter (in.)
Maximum
7.9506
Minimum
7.6787
Mean
7.8161
Ovality (%) Based on
Max Dia.
1.721
Min. Dia.
1.757
C.3.1.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness of the liner was found to be 7.57 mm ± 0.09 mm as shown in Figure
C-45. The design thickness was not available; therefore, no comparison was made.
C-37
-------
Houston Greiner
7.5
7.0
6.5
6.0
Average Thickness 7.57mm ± 0.09 mm
n n
SI 52 S3 54 S5 S6 S7 S8 S9 510 Sll 512 513 514 515 516 517 S18 519 520
Measured specimens
Figure C-45. Houston Greiner Dr.: Average Thickness of the Liner Sample
C.3.1.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure C-46. The obtained
values were between 0.924 and 0.949. The average specific gravity was 0.94 ± 0.01.
Houston Greiner
Average 0.94 ± 0.01
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
odd
d o
o o
1234567
9 10 11 12 13 14 15 16 17 18 19 20
Number of Samples
Figure C-46. Houston Greiner Dr.: Specific Gravity of the Liner
C.3.1.7 Tensile Test (ASTMD638). Specimens, as described in ASTM D638, were cut from the
retrieved polyethylene liner using a router and a band saw. A total of 14 specimens were prepared and
tested. The sides of the specimens were smoothed using a grinder. The water jet cutter could not be used
as the liner was curved and too small to be mounted inside the cutting board. The tensile test results are
C-38
-------
presented in Figure C-47 and Table C-31. The average tensile strength was 2,979 ±239 psi and the
average tensile modulus was 137,875 ± 81,053 psi.
Tensile Modulus of Elasticity
3500
0.1
0.3 0.4 0.5
Strain, in/in
0.6
0.7
0.8
Figure C-47. Houston Greiner Dr.: Stress - Strain Curves from Tensile Testing
Table C-31. Houston Greiner Dr.: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Average
St. Dev
Area
(in.2)
0.1489
0.1444
0.1529
0.1697
0.1788
0.1601
0.1595
0.1496
0.1588
0.1650
0.1576
0.1485
0.1588
0.1739
Peak Load
(Ib)
511.87
481.65
488.13
421.26
552.08
462.55
477.53
431.69
449.04
472.44
467.26
441.78
477.95
480.66
472.56
33.10
Peak Stress
(psi)
3,438
3,336
3,192
2,482
3,088
2,889
2,994
2,886
2,828
2,863
2,965
2,975
3,010
2,764
2,979
239
Tensile
Modulus
(psi)
447,587
195,890
183,295
199,023
143,327
154,311
136,706
151,878
142,051
151,199
125,190
131,959
151,763
191,900
137,875
81,053
C. 3.1.8 Flexural Test (ASTM D 790). Specimens, as described in ASTM D790, were cut from the
retrieved liner using a router and a band saw. A total of 15 specimens were prepared and tested. The
sides of the specimens were smoothed using a grinder. The water jet cutter could not be used as the liner
C-3 9
-------
was curved and too small to be mounted inside the cutting board. The flexure test results are presented
graphically in Figure C-48 and are listed in Table C-32. The average flexural modulus was 100,636 ±
4,728 psi and the average flexural strength was 3,152 ±116 psi. The bending modulus reaches the
classification limits of Class 4 from the ASTM D3350, but no material information was available on this
liner.
Flexural Stress Vs Flexural Strain
I
a'
flj
t
Flexural Strain, In/In
Figure C-48. Houston Greiner Dr.: Stress - Strain Curves from Flexural Testing
Table C-32. Houston Greiner Dr.: Flexure Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0076
0.0073
0.0076
0.0074
0.0075
0.0085
0.0080
0.0084
0.0080
0.0080
0.0083
0.0083
0.0086
0.0081
0.0083
Peak Load
(Ib)
23.36
22.35
23.10
23.54
22.93
27.12
27.96
25.54
25.66
24.96
25.44
26.27
27.26
25.87
26.81
25.21
1.77
Peak Stress
(psi)
3,074
3,062
3,039
3,181
3,057
3,191
3,495
3,040
3,208
3,120
3,065
3,165
3,170
3,194
3,230
3,152
116
Flexural
Modulus
(psi)
109,133
101,058
94,260
103,207
106,024
101,023
106,383
96,367
104,519
92,962
100,327
96,736
97,300
97,680
102,570
100,636
4,728
C.3.1.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved polyethylene liner with
C-40
-------
a band saw. A total of 400 readings were taken on the inner and outer surfaces of the liner specimens.
The average recorded hardness values are shown in Figure C-49. The hardness of the surface exposed to
the flow (inner surface) was found to be slightly lower than that of the protected (outer) surface.
Houston Greiner
Average of Inner Surface 52.8 ± 1.14
Average of Outer Surface 58.1 ± 1.15
Z
Q
01
30
15
o 1
coa
3JS
1
i
1
--
iH t~- (N CO r-J;lD. :r-j m r-J:r-» *H in
LTI in; in:in iniui1 'tnin m in in in
234567
-'
r>iin (NiOd ro(rfl ^rfld -*00': :tNI< fri r*i 00
•_-.•_-'. iniin Lom' m.in m m mm1 m:i/i miin
8 9 10 11 12 13 14 15
r^aS ff a\ r-Jm *Jo fri
LO in. m in «n in im AD in
16 17 18 19 20
Specimen
Figure C-49. Houston Greiner Dr.: Shore D Hardness Readings for the Liner's Inner and Outer
Surfaces
C.3.1.10 Pipe Stiffness. Pipe stiffness was measured using the UTM equipped with parallel plates
according to ASTM D2412. Three 6 in. long specimens were cut from the liner using a table saw; the
load was applied at 0.50 in./min. According to ASTM D2412, the deformation of the pipe was limited to
5% of the inside diameter. The test results are shown in Table C-33. The average value was found to be
41.21bf/in./in.
Table C-33. Houston Greiner Dr.: Pipe Stiffness Test Results
Sample
1
2
3
Average
Peak Load, Ib
15.11
13.54
12.94
13.86
Pipe Stiffness at 5% Deformation of Inside
Diameter (lbf/in./in.)
44.89
40.22
38.46
41.19
C-41
-------
C.3.2 Houston Norton: A Black Polyethylene Slipline Sample in an 8 in. Concrete Host Pipe.
The sample was recovered between manholes 088 and 091 on Friendship/Norton Drive, Houston, Texas
on March 14, 2013. The host pipe and liner information are provided in Table C-34.
Table C-34. Houston Norton: Host Pipe and Liner Information
Host pipe
Liner Thickness
Liner Type
Year of Installation
Liner
Vendor/Supplier
Non-reinforced concrete pipe 8 in. installed between
1956
1953-
Approximately 8 mm
Black polyethylene pipe
Unknown but probably at least 15 years old
Unknown
C.3.2.1 Visual Inspection. The black polyethylene slipline sample was found in good condition.
cracks were visible on the pipe. There was no evidence of soil accumulation on the samples when
received at the TTC laboratory. The retrieved sample is shown in Figure C-50.
No
Figure C-50. Houston - Norton Dr.: Images of the Black Polyethylene Slipliner Section Prior to
Testing
C.3.2.2 Annular Gap. Annular gaps were not measured at the site on this sample and the
sample was received at the TTC without any host pipe attached to it; therefore, no annular gap
readings were obtained.
C.3.2.3 Environmental Service Conditions. No soil samples were collected. Waste material (2 g)
was collected from the inside of the sample and stirred in 200 mL of distilled water to allow pH testing.
The inside pH value was 7 to 8. No test could be conducted for the outside value.
C.3.2.4 Ovality. The sample's ovality was measured using software as described in Section C. 1.1.4.
The pipe ready for tracing and the resulting diameter measurements are shown in Figure C-51. The
detailed ovality calculation is shown in Table C-35. Based on the maximum diameter measured, the
ovality was 2.83%, while the ovality was 3.33% when calculated based on the minimum diameter. The
higher ovality value was used as the representative value.
C-42
-------
Figure C-51. Houston - Norton Dr.: Ovality of the Liner
Table C-35. Houston Norton Dr.: Ovality Calculation
Measured
Diameter (in.)
6.9021
6.9318
6.9608
6.9108
6.8762
6.7817
6.6670
6.5909
6.5434
6.5717
6.6739
6.8179
Diameter (in.)
Maximum
6.9608
Minimum
6.5434
Mean
6.77
Ovality (%) Based on
Max Dia.
2.834
Min. Dia.
3.332
C.3.2.5 Thickness. A total of 120 readings were taken on 20 1 in. x 1 in. samples cut from different
locations of the specimen. The thickness was measured randomly using a micrometer with a resolution of
±0.0025 mm. The average thickness of the liner was found to be 8.447 mm ± 0.05 mm as shown in
Figure C-52. The design thickness was unavailable; therefore, no comparison was made.
C-43
-------
Houston Norton
1
I
8,6
8.4
8,2
SO
7,8
7.6
7.4
7.!
rjp
Averiigc ThkfcmH 8.44? mm i 0,05 mm
51 52 53 54
Measured specimens
5t S/ 58 59 SID 511 512 SB 514 Sli 516 517 518 S19 520
Figure C-52. Houston-Norton Dr.: Average Thickness of the Liner Sample
C.3.2.6 Specific Gravity. The specific gravity of the liner was measured on 20 1 in. x 1 in. samples
in accordance with ASTM D792. The specific gravity values are shown in Figure C-53. The obtained
values were between 0.93 and 0.98. The average specific gravity was 0.97 ± 0.01.
Houston Norton
i
1.00
0.50
0.40
0.30
0.20
i E
!
; i
'• °
! i
; c
t
i Y
i 5
! «
•• i
c
i c
i j
<
5 t
*
0
1 C
I i
i
j f
; •(
i 1
1 c
! ;
e
i t
1
1 I
- 1
1 (
J C
; i
i j
» <
«
\ :
i <
i 1
O
/ s si JO 11 12 i:t 14 is
Number of Samples
Figure C-53. Houston Norton Dr.: Specific Gravity of the Liner
C.3.2. 7 Tensile Test (ASTM D638). Specimens, as described in ASTM D638, were cut from the
retrieved polyethylene slipliner using a router and a band saw. A total of 15 specimens were prepared and
tested. The sides of the specimens were smoothed using a grinder. A water jet cutter could not be used as
the liner was curved and too small to be mounted inside the cutting board. The tensile test results are
presented in Figure C-54 and Table C-36. The average tensile strength was 3,098 ± 542 psi and the
average tensile modulus was 147,875 ± 32,900 psi. The elongation at break varied from around 24% to
more than 70%. Sample 13 produced a lower peak stress value than the others possibly due to a localized
C-44
-------
crack created while preparing the sample. The modulus value for the sample was found to be reasonable
and, therefore, the test data obtained for this sample were kept.
Tensile Modulus of Elasticity
Sample 1
Sample 2
Sample 3
Sampled
Sample
Sample 6
Sample 7
Samples
Sample 9
—Sample 10
—Sample 11
— Sample 1?
Sample 13
— Sample 14
Sample IS
Figure C-54. Houston Norton Dr.: Stress - Strain Curves from Tensile Testing
Table C-36. Houston Norton Dr.: Tensile Test Results
Sample
ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.1767
0.1695
0.1730
0.1731
0.1708
0.1796
0.1720
0.1760
0.1667
0.1628
0.1766
0.1835
0.1581
0.1737
0.1695
Peak Load
(Ib)
619.77
604.62
579.18
639.41
565.05
541.28
506.41
524.78
569.58
560.14
514.38
515.15
221.27
538.74
513.27
534.20
95.73
Peak Stress
(psi)
3,507
3,567
3,348
3,694
3,308
3,014
2,944
2,982
3,417
3,441
2,913
2,807
1,400
3,102
3,028
3,098
542
Tensile
Modulus
(psi)
225,012
155,477
162,352
183,404
137,874
91,292
108,415
143,188
170,930
128,383
167,460
130,589
113,518
148,039
152,192
147,875
32,900
C.5.2.8 Flexural Test (ASTMD790). Specimens, as described in ASTM D790, were cut from the
retrieved polyethylene slipliner using a router and a band saw. A total of 15 specimens were prepared and
tested. The sides of the specimens were smoothed using a grinder. A water jet cutter could not be used as
C-45
-------
the liner was curved and too small to be mounted inside the cutting board. The flexure test results are
presented graphically in Figure C-55 and are listed in Table C-37. The average flexural modulus was
101,881 ± 10,373 psi and the average flexural strength was 3,174 ± 255 psi.
Flexural Stress Vs Flexural Strain
Flexural Strain, In/In
Figure C-55. Houston Norton Dr.: Stress - Strain Curves from Flexural Testing
Table C-37. Houston Norton Dr.: Flexure Test Results
Sample ID
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
St. Dev
Area
(in.2)
0.0088
0.0089
0.0095
0.0090
0.0097
0.0096
0.0107
0.0104
0.0111
0.0108
0.0103
0.0100
0.0094
0.0100
0.0113
Peak Load
(Ib)
30.96
31.23
33.24
30.94
33.28
31.89
31.24
30.90
32.70
31.62
30.07
30.97
30.41
30.38
32.15
31.47
1.00
Peak Stress
(psi)
3,518
3,509
3,499
3,438
3,431
3,322
2,920
2,971
2,946
2,928
2,919
3,097
3,235
3,038
2,845
3,174
255
Flexural
Modulus
(psi)
115,606
117,596
114,931
112,626
105,718
104,838
88,202
96,315
84,951
90,610
97,871
99,754
106,552
99,936
92,721
101,881
10,373
C.3.2.9 Surface Hardness. A Shore Type D durometer (ASTM D2240) was used to determine the
hardness of the liner samples. Samples (1 in. x 1 in.) were cut from the retrieved polyethylene slipliner
with a band saw. A total of 400 readings were taken on the inner and outer surfaces of the liner
C-46
-------
specimens. The average recorded hardness values are shown in Figure C-56. The hardness of the surface
exposed to the flow (inner surface) was found to be slightly lower than that of the protected (outer)
surface.
Houston Norton
of Inrnr Surlmn bS./ t l.M
ot Outer Surface 56.4 ±1.73
Q
1234567
9 10 11 12 13 M 15 16 17 18 19 20
Specimen
Figure C-56. Houston Norton Dr.: Shore D Hardness Readings for the Liner's Inner and Outer
Surfaces
C.3.2.10 Pipe Stiffness. Pipe stiffness was measured using the UTM equipped with parallel plates
according to ASTM D2412. Three 6 in. long specimens were cut from the liner using a table saw; the
load was applied at 0.50 in./min. According to ASTM D2412, the deformation of the pipe was limited to
5% of the inside diameter. The test results are shown in Table C-38. The average value was found to be
61.61bf/in./in.
Table C-38. Houston Norton Dr.: Pipe Stiffness Test Results
Sample
1
2
3
Average
Peak Load, Ib
20.37
20.74
21.10
20.74
Pipe Stiffness at 5% Deformation of Inside
Diameter (lbf/in./in.)
60.51
61.63
62.70
61.61
C-47
-------
APPENDIX D
QUALITATIVE OBSERVATIONS CONCERNING
WASTEWATER REHABILITATION PERFORMANCE
-------
To supplement the physical data, municipalities contacted about participating in the physical sample
retrieval were also asked to provide information about their overall experiences with various
rehabilitation technologies. This section describes additional qualitative performance evaluation
information for the rehabilitation technologies selected in the current retrospective study including cured-
in-place pipe (CIPP), polyvinyl chloride (PVC) fold-and-form, deform/reform high density polyethylene
(HDPE), and sliplining. This appendix summarizes the qualitative assessments made by municipalities
about the performance of each technology related to installation and long-term performance issues.
D.I CIPP (Thermal and UV Cure)
CIPP is by far the dominant rehabilitation method in use for gravity sewers in the U.S. It involves the
insertion of a liquid-resin-impregnated fabric into the host pipe where it is held tightly against the inside
wall of the host pipe while it is cured thermally or by ultraviolet (UV) light. A fuller description of CIPP
is provided in Section 3.1 of this report and also with significantly more detail in EPA (2010). For this
study, seven municipalities in the U.S. were selected to participate by providing CIPP samples
(Columbus, Denver, Houston, Indianapolis, Nashville, Northbrook, and New York). In addition, the City
of Omaha that was contacted about providing samples also provided qualitative information. Not all of
the participating municipalities provided qualitative information and, hence, five responses on the
performance of CIPP liners are included as summarized in Table D-l.
Table D-l. Types and Amounts of CIPP for Participating Municipalities
Municipality
Houston, TX
Indianapolis, IN
Nashville, TN
New York, NY
Omaha, NE
System
Length
(mi)
6,950
NP
3,096
6,400
2,412
CIPP
Thermal Cure (ft)
1,177,440
100,000
1,500,000
NP
39,400
UV Cure (ft)
None
100
None
None
None
NP = Not provided
The lengths installed by individual municipalities ranged from 39,400 ft to approximately 1.5 million ft.
All had used thermal cure CIPP and one municipality also reported using UV cure CIPP (Indianapolis)
starting in 2013. The first installations among these municipalities for thermal cure CIPP were in the
1970s in New York. All of the responses presented in this section are for thermal cured CIPP (unless
noted separately as related to UV cure).
As shown in Table D-2, the participating utilities indicated the severity of the installation issues for CIPP
to be "almost none" to "minor" and primarily occurring at an estimated frequency below 4% (four out of
five participating utilities). Four out of five participating utilities considered the severity of long-term
performance issues for CIPP to be "almost none" to "minor" with one listing this as "moderate." The
occurrence of such long-term performance issues was assessed at an estimated frequency below 4% (five
out of five participating utilities). The overall assessment of long-term cost-benefit value for thermal cure
CIPP was deemed to be "high" for all of the participating municipalities. For UV cure CIPP, the City of
Indianapolis (which used UV cure CIPP for the first time in 2013) gave a "reasonable" assessment.
D-l
-------
Table D-2. Qualitative CIPP Considerations
Municipality
Houston
Indianapolis
Nashville
New York
Omaha
First year used
1986
1980s
1989
1970s
1986
Frequency of
CIPP installation issues
Ol
a
O
Z
£
o
X
X
X
£
i-H
X
5?
OJ\
X
^o
o
Cj)
o
5?
o
A
Severity of
CIPP
installation
issues
Almost none
X
X
X
s«
0
X
Moderate
X
Ol
1
Frequency of
CIPP long-term
performance issues
Ol
a
O
Z
X
£
o
X
X
X
^
i-H
X
5?
OJ\
^o
O
Cj)
o
5?
o
A
Severity of
CIPP long-
term
performance
issues
Almost none
X
X
X
s«
0
X
Moderate
X
Ol
1
Overall
assessment
of
CIPP
long-term
cost-benefit
value
o
Reasonable
S
X
X
X
X
X
As summarized below, general input on CIPP installation issues was received at the Trenchless
Technology Center's (TTC) Colorado Municipal Users' Forum on September 26, 2013 and the Minnesota
Municipal Users' Forum on May 15, 2013.
The types of installation issues identified included the following:
• Wrinkles/folds in liner; poorly sized liner
• Missed taps or over/under cutting
• Failure of resin to cure /inadequate curing resources
• Collapse of liner
• Rough cuts on taps
• Inconsistent resin impregnation
• Care and experienced installers a requirement for success
• Premature resin curing
• Resin slugs in laterals
• Inability to span voids
• Inadequately prepared/televised pipe
• Styrene odor complaints for larger diameter installations.
The key long-term performance issues identified were as follows:
• Delamination of sealing layer
• Excessive wrinkles causing constriction in main
• Wrinkles impact cleaning and closed-circuit television (CCTV)
• Infiltration at lateral openings
• Roots still enter main from non-rehabilitated laterals
D-2
-------
• Large piece of CIPP liner found on wastewater treatment plant screen (source location unknown
at present).
Other key issued related to CIPP rehabilitation were as follows:
• Maintenance practices need to be modified/controlled to avoid damage
• Used in larger diameters where loss of cross-section is less important
• Pipe bursting preferred when diameter less than 15 in. and depth less than 15 ft; CIPP preferred
for diameters between 24 in. and 108 in.
• Tried and true method; Continuing to use CIPP; product holds up well
• Great product, but still have some water entering the system through annular space
• Good results for both thermal and UV cure CIPP; no long-term failures.
D.2 Fold-and-Form (PVC)
The vast majority of PVC fold-and-form rehabilitation in the U.S. used the "Ultraliner" technology, but it
is not certain that all of the municipal responses under this category do refer specifically to the Ultraliner
system. The technology was introduced into the U.S. market in the 1990s and had an important impact of
providing competition to the CIPP process.
Three municipalities provided fold-and-form samples for the retrospective study (Denver, Miami, and
Nashville). Of these three participating utilities, only Nashville provided qualitative information on fold-
and-form performance. Nashville had by far the greatest use of the technology with approximately
225,000 ft (42.6 miles) installed. This was supplemented with technology assessment information from
Littleton, Colorado and Westminster, Colorado. These two additional responding municipalities could
serve as potential future sampling locations if additional PVC fold-and-form samples are sought. As
shown in Table D-3, these three municipalities had installation lengths ranging from 5,000 to 225,000 ft.
Since each of the municipalities reported first installations in the 1990s, there have been 14 or more years
of experience with the fold-and-form technology.
Table D-3. Types and Amounts of PVC Fold-and-Form by Municipalities
Municipality
Littleton, CO
Nashville, TN
Westminster, CO
System
Length
(mi)
130
3,096
410
Fold-and-Form
PVC
(ft)
10,000
225,000
5,000
As shown in Table D-4, the utilities reported the severity of the installation issues for PVC fold-and-form
to be "almost none" to "minor" and primarily occurring at an estimated frequency below 10% (three out
of three participating utilities). The responding utilities reported the severity of long-term performance
issues for PVC fold-and-form to be "almost none" to "moderate" and primarily occurring at an estimated
frequency below 10% (three out of three participating utilities). As shown in Table D-4, the overall
assessment of long-term cost-benefit value by all three responding municipalities was "reasonable." It is
worth noting that Nashville, with the most experience with fold-and-form, estimated the lowest frequency
of both installation and long-term performance issues and the lowest associated severity of impact.
D-3
-------
Table D-4. Qualitative PVC Fold-and-Form Considerations
Municipality
Littleton
Nashville
Westminster
•a
01
3
•—
E
1998
1990s
1997
Frequency of FnF
installation issues
Ol
I
5?
i-H
si
X
^
i-H
X
^
Ol
X
X
X
si
s
FnF = fold-and-form
The key issues identified for PVC fold-and-form are:
• Creep and/or thermal longitudinal movement in the liner after installation (i.e., the liner is not
locked in place longitudinally within the host pipe). When this occurs after the liner cuts have
been made for service reconnection, then service connections may become blocked.
• Inaccurate measurement of host pipe ID or variations in this ID can cause a mismatch with the
liner being installed, resulting in folds in the liner after installation.
The types of installation issues identified for PVC fold-and-form included the following:
• Under heating caused pipe to get stuck requiring liner to be pulled, reheated, and reinstalled
• Folds due to improper match to host pipe ID
• Creep of the liner; liner movement covering service connections.
The type of long-term performance issues for PVC fold-and-form included the following:
• Liner moved over time causing misalignment of lateral service connections
• Ovality issues
• Service connection failures.
Other considerations for PVC fold-and-form performance included the following:
• Requires careful inspection and observance over time
• No longer used due to movement within the pipe
• Dependent on installation crews for quality control
• Variations in host pipe ID can promote defects
• More difficult to make service line reconnections.
D-4
-------
D.3 Deform-Reform (HOPE)
Deform-reform rehabilitation using a folded HDPE pipe has a number of technology variants that have
been used in both gravity flow sewers and pressure pipes.
Two municipalities provided deform-reform HDPE samples for the retrospective study (Denver and
Nashville). However, neither provided qualitative information to assess the performance of deform-
reform HDPE. This was supplemented with technology assessment information from Shreveport,
Louisiana, which could serve as a potential future sampling location if additional samples are pursued.
This municipality estimated the frequency of both installation and performance issues at 0 to 1% with
minor severity of impacts in both cases. Their overall assessment of long-term cost-benefit and value was
assessed as "reasonable." Some problems were noted with reforming during installation and significant
issues relating to the longitudinal movement of the liner within the host pipe after the cutting of service
reconnections.
D.4 Sliplining (Large Diameter)
Large diameter sliplining typically involves the segmental slip lining of large diameter host pipes by
sliding sections of new pipe within the old pipe, often without bypassing the existing flow. After
sliplining, the annular space between the lining and the host pipe is typically grouted. A common type of
pipe used for sliplining is a fiberglass pipe and the pipe joints for sectional installations are typically
configured to provide a push-fit sealing as the sections are joined together.
As shown in Table D-5, five municipalities (Houston, Littleton, Nashville, Shreveport, and Westminster)
provided qualitative performance information for both large and small diameter sliplining. The City of
Houston had the largest length of large diameter sliplining reported at 15,840 ft, although it was only able
to provide small diameter sliplining samples for the study due to the cost and difficulty in retrieving
samples and repairing the slipliner in large diameter installations. The additional four municipalities
could serve as potential future sampling locations if supplemental sliplining samples are sought. The first
uses of sliplining in these responses were reported by Nashville from the 1960s.
Table D-5. Types and Amounts of Large and Small Diameter Sliplining by Municipalities
Municipality
Houston, TX
Littleton, CO
Nashville, TN
Shreveport, LA
Westminster, CO
System
Length
(mi)
6,950
130
3,096
1,079
410
Large
Diameter
Sliplining
(ft)
15,840
1,050
Small
Diameter
Sliplining
(ft)
NE
NE
10,000
36,960
0
800
Note: NE = No estimate
As shown in Table D-6, the overall assessment of long-term cost-benefit value by three responding
municipalities (Houston, Littleton, and Nashville) with large diameter sliplining was "reasonable" to
"high." It is worth noting that Houston, with the most experience identified specifically as large diameter
sliplining, did identify some installation issues (1 to 4%) and some long-term performance issues (0 to
1%), but gave an overall assessment of long-term cost-benefit value of "high."
D-5
-------
Table D-6. Qualitative Large Diameter Sliplining Considerations
Municipality
Houston
Littleton
Nashville
•a
=
C5
E
1999
2011
1960s
Frequency of large
diameter sliplining
installation issues
1
X
5?
i-H
si
X
£
1
i-H
X
5?
o\
.0
0^
O
Cj)
o
5?
o
Severity of
large
diameter
sliplining
installation
issues
0)
a
Almost n
X
X
X
o
a
§
£
Modera
01
VI
Frequency of large
diameter long-term
performance issues
o
1
X
X
5?
i-H
si
X
^
i-H
5?
a^
i
.0
0^
O
si
5?
o
Severity of
large
diameter
long-term
performance
issues
n>
a
Almost n
X
X
X
o
a
§
£
Modera
01
VI
assessment
of large
diameter
long-term
cost-benefit
value
o
Reasona
X
S
X
X
The key issues identified for large diameter sliplining are:
• The benefits of maintaining flow during installation; limited bypass requirements
• Significant decrease in internal diameter after slip lining but improved roughness coefficients
• Poor joint alignment/sealing issues during installation leading to infiltration at joints
• Pipe stress may be introduced by friction during installation and by annular space grouting.
The types of installation issues indicated for large diameter sliplining included the following:
• Limited bypass needed
• Friction induced lining pipe stress
• Poor joint alignment
• Back-grouting-induced lining pipe stress
• Some adjustment required with bends.
The type of long-term performance issues for large diameter sliplining included the following:
• Does decrease internal diameter
• Infiltration at joints.
Other issues related to large diameter sliplining included the following:
• Used for large diameter for better structural integrity and less flow friction
• Looks good after rehabilitation
• Good results
• Both segmental and fused pipe methods used
• Creep issues for fused pipe
• Segmental method allows flow through during installation.
D-6
-------
D.5 Sliplining (Small Diameter)
Small diameter sliplining may use either segmental or fused lengths of pipe for insertion. All of the
specifically identified small diameter sliplining was reported as being started in the 1990s. Houston
provided two 8 in. sliplining samples for the retrospective study. As shown in Table D-7, the overall
assessment of long-term cost-benefit value was "poor" to "reasonable" with the lower rating associated
with a comment of removal of the slipline due to grease buildup.
Table D-7. Qualitative Small Diameter Sliplining Considerations
Municipality
Shreveport
Westminster
•a
Ol
f>
3
E
1990s
1990
Frequency of small
diameter sliplining
installation issues
I
5?
i-H
si
X
^
i-H
X
5?
STv
5?
o
2
5?
o
Severity of
small diameter
sliplining
installation
issues
01
a
Almost no
o
a
X
X
O>
Moderat
Severe
Frequency of small
diameter sliplining
long-term performance
issues
I
5?
i-H
si
X
^
i-H
X
^
-------
D.6 Overall Summary of the Experience of the Municipalities Participating in the Study
The responses from the municipalities described above indicate a significant degree of satisfaction with
almost all of the rehabilitation methods with which they had experience. Most municipalities reported
that the technologies and/or their installation were not completely trouble free. However, the percentages
of problems or issues in terms of installation or long-term performance were generally low and
considered acceptable. The overall value of the rehabilitation technologies issues was generally perceived
to be high.
CIPP technology has become the dominant rehabilitation technology for sewer collection systems with
some of the other technologies that were introduced in past decades disappearing from the marketplace -
either due to some of the performance issues identified above or commercial issues in technology delivery
or cost competitiveness. Nevertheless, there are many circumstances in which other technologies do
compete with CIPP or offer solutions where CIPP would not be applicable.
While the municipalities responding indicate overall satisfaction with their rehabilitation technologies and
long-term performance appears to be good, there is still plenty of room for improvement in the quality
control of rehabilitation efforts.
D-8
-------
APPENDIX E
RELEVANT ASTM STANDARDS
-------
The following table lists ASTM standards that are referenced in this report.
Standard
ASTM C 128
ASTM C 136
ASTM D543
ASTM D62 1-64
(1988)
ASTM D638
ASTM D648
ASTMD671
ASTM D695
ASTM D696
ASTM D732
ASTM D790
ASTM D792
ASTM D953
ASTM D 1693
ASTM D 1784
ASTM D2122
ASTMD2216
ASTMD2412
ASTM D2583
ASTM D3350
ASTMD5813
ASTME1356
ASTM F5 85
ASTMF1216
Description
Standard Test Method for Density, Relative Density (Specific Gravity), and
Absorption of Fine Aggregate
Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates
Standard Practices for Evaluating the Resistance of Plastics to Chemical
Reagents
Test Methods for Deformation of Plastics Under Load
(Withdrawn 1994)
Standard Test Method for Tensile Properties of Plastics
Standard Test Method for Deflection Temperature of Plastics Under Flexural
Load in the Edgewise Position
Standard Test Method for Flexural Fatigue of Plastics by Constant Amplitude
of Force (Withdrawn 2002)
Standard Test Method for Compressive Properties of Rigid Plastics
Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics
Between -30°C and 30°C with a Vitreous Silica Dilatometer
Standard Test Method for Shear Strength of Plastics by Punch Tool
Standard Test Methods for Flexural Properties of Unreinforced and
Reinforced Plastics and Electrical Insulating Materials
Standard Test Methods for Density and Specific Gravity (Relative Density) of
Plastics by Displacement
Standard Test Method for Bearing Strength of Plastics
Standard Test Method for Environmental Stress-Cracking of Ethylene Plastics
Standard Specification for Rigid Poly(Vinyl Chloride) (PVC) Compounds and
Chlorinated Poly(Vinyl Chloride) (CPVC) Compounds
Standard Test Method for Determining Dimensions of Thermoplastic Pipe and
Fittings
Standard Test Methods for Laboratory Determination of Water (Moisture)
Content of Soil and Rock by Mass
Standard Test Method for Determination of External Loading Characteristics
of Plastic Pipe by Parallel-Plate Loading
Standard Test Method for Indentation Hardness of Rigid Plastics by Means of
a Barcol Impressor
Standard Specification for Polyethylene Plastics Pipe and Fittings Materials
Standard Specification for Cured-In-Place Thermosetting Resin Sewer Piping
Systems
Standard Test Method for Assignment of the Glass Transition Temperatures
by Differential Scanning Calorimetry
Standard Guide for Insertion of Flexible Polyethylene Pipe Into Existing
Sewers
Standard Practice for Rehabilitation of Existing Pipelines and Conduits by the
Inversion and Curing of a Resin-Impregnated Tube
E-l
-------
Standard
ASTMF1504
ASTMF1533
ASTM F1743
ASTMF1867
ASTM F 1871
ASTMF2019
ASTM F2599
Description
Standard Specification for Folded Poly(Vinyl Chloride) (PVC) Pipe for
Existing Sewer and Conduit Rehabilitation
Standard Specification for Deformed Polyethylene (PE) Liner
Standard Practice for Rehabilitation of Existing Pipelines and Conduits by
Pulled-in -Place Installation of Cured-in -Place Thermosetting Resin Pipe
(CIPP)
Standard Practice for Installation of Folded/Formed Poly (Vinyl Chloride)
(PVC) Pipe Type A for Existing Sewer and Conduit Rehabilitation
Standard Specification for Folded/Formed Poly (Vinyl Chloride) Pipe Type A
for Existing Sewer and Conduit Rehabilitation (Withdrawn 201 1)
Standard Practice for Rehabilitation of Existing Pipelines and Conduits by the
Pulled in Place Installation of Glass Reinforced Plastic (GRP) Cured-in-Place
Thermosetting Resin Pipe (CIPP)
Standard Practice for The Sectional Repair of Damaged Pipe By Means of An
Inverted Cured-In-Place Liner
E-2
------- |