&EPA
United States
Environmental Protection
Agency
A Retrospective Evaluation
of Cured-in-Place Pipe (CIPP)
Used in Municipal Gravity Sewers
Office of Research and Development
National Risk Management Research Laboratory -Water Supply and Water Resources Division
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A Retrospective Evaluation
of Cured-in-Place Pipe (CIPP)
Used in Municipal Gravity Sewers
by
Erez Allouche, Ph.D., P.E., Shaurav Alam, Jadranka Simicevic,
and Ray Sterling, P.h.D., P.E.,
Trenchless Technology Center at Louisiana Tech University
Wendy Condit, P.E., Ben Headington, and John Matthews, Ph.D.
Battelle Memorial Institute
Ed Kampbell, Tom Sangster, and Dec Downey, Ph.D.
Jason Consultants, Inc.
Contract No. EP-C-05-057
Task Order No. 58
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
2890 Woodbridge Avenue (MS-104)
Edison, NJ 08837
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
September 2011
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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) 58 of Contract No. EP-C-05-057 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
Pipe rehabilitation and trenchless replacement technologies have seen a steadily increasing use and
represent an increasing proportion of the annual expenditure on operations and maintenance of 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. The major reasons
for retrospective evaluation of rehabilitation systems are needed include: data gaps in predicting
remaining asset life of pipes and how long rehabilitation techniques can extend that life; and to assess
whether the originally planned lifetime is reasonable based on current condition. The goals of this project
were to draw attention to the need for this type of evaluation and to develop evaluation protocols that are
technically and financially feasible for carrying out these evaluations.
The initial project focuses on cured-in-place pipe (CIPP) liners because they were the first trenchless
liners (other than conventional slipliners) to be used in pipe rehabilitation and they hold the largest market
share. The pilot testing used CIPP samples from both large and small diameter sewers in two cities that
were in excellent condition after being in use for 25, 23, 21, and 5 years, respectively. 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 was gathered as appropriate including: external soil
conditions and pH, and internal waste stream pH. Three of the liners had already been in service for
nearly half of their originally expected service life, but overall, there is no reason to anticipate that the
liners evaluated will not last for their intended lifetime of 50 years and perhaps beyond.
Given the insights provided by the pilot studies, an expansion of the retrospective study is recommended
to create a broader database to better define the expected life of sewer rehabilitation technologies.
Specifically, it is recommended that the retrospective program be extended to: cover additional CIPP
sample retrieval in other cities, pilot studies of other rehabilitation technologies; capture locally
interpreted data from other cities; encourage sewer agencies to keep as-installed material test data for later
comparison with follow-up testing; and adapt, develop, and/or calibrate non-destructive testing (NDT)
methods that could use small physical samples that are easily retrieved robotically from inside the pipe.
in
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ACKNOWLEDGMENTS
This report has been prepared with input from the research team, which includes Battelle, the Trenchless
Technology Center (TTC) at Louisiana Tech University, and Jason Consultants. The technical direction
and coordination for this project was provided by Dr. Ariamalar Selvakumar of the Urban Watershed
Management Branch. 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 City and County of Denver (Lesley Thomas, Wayne Querry, and
Randy Schnicker) and the City of Columbus (James Gross II, Mike Griffith, and Dave Canup) for seeing
the value of the proposed study and working with the research team to find ways to cover the costs of the
sample retrieval and repair of the host pipe and/or liner at each sample site. Thanks also go to Joe
Barsoom, former Director of the Sewer Division for the City and County of Denver, who assisted greatly
in all aspects of the evaluations in Denver. 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
Trenchless Technology Center (TTC) and Battelle laboratories for further study. In Denver, Wildcat
Construction contributed in-kind support to the retrieval of a liner sample from the brick sewer.
The authors would like to thank the stakeholder group members for review of the report (Joe Barsoom,
Tom Iseley, Walter Graf, and James Gross II).
IV
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EXECUTIVE SUMMARY
Pipe rehabilitation and trenchless pipe replacement technologies have seen a steadily increasing use over
the past 30 to 40 years and represent an increasing proportion of the approximately $25 billion annual
expenditure on operations and maintenance of the nation's water and wastewater infrastructure (EPA,
2002). Despite the massive public investment represented by the use of these technologies, there has been
little formal and quantitative evaluation of 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 some hard
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 nearly 30 years in the U.S. and 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.
While the long-term goal of the retrospective evaluation effort is to provide significant and credible
feedback on performance to the system owners and the engineers who specify rehabilitation and
replacement technologies, a few isolated evaluations of projects with a variety of existing and service
conditions cannot provide statistically significant data. Thus, the goals for the effort within this project
are to draw attention to the need for this type of evaluation and to develop evaluation protocols that are
technically and financially feasible for carrying out evaluations of the main rehabilitation and trenchless
replacement technologies. The protocols should produce useful results at a cost that municipalities will
be willing to pay to participate in the data collection. The subsequent drive will be to encourage
municipalities and other system owners to conduct their own evaluations and then to contribute their data
to a common database where the results can be aggregated on a national basis. The initial project
described in this report focuses on cured-in-place pipe (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 from a convenient site. For the larger
diameter sewers (36 to 48 in. diameter), CIPP liner samples were cut from the interior of the pipe and the
liner patched in situ.
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 was gathered as appropriate to
each retrieval process including: external soil conditions and pH, and internal waste stream pH. The
findings from the testing conducted so far are presented in detail in this report and a short overall
summary is given below.
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
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samples had a flexural modulus value that was lower than the originally specified value, but this cannot
be tied directly to deterioration of the liner over time. In the case of the Denver 48-in downstream liner,
in particular, it appears likely that the poor physical test properties may have resulted from variability
within the liner rather than a change overtime. Some indication of a softening of the interior surface of
the liner that 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 present on the inside surface of the CIPP liner. For newer CIPP liners,
a different handling/inner layer with greater durability is used.
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 appeared to relate 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 is no reason to anticipate that the liners evaluated in this pilot study will not last for their
intended lifetime of 50 years and perhaps well beyond.
Given the insights provided by the pilot studies in Denver and Columbus, an expansion of the
retrospective evaluation study is recommended to create a broader national database that would help to
better define the expected life of sewer rehabilitation technologies. Specifically, it is 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 survey to capture the locally interpreted data from a wide range of cities 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 outcome of an effective evaluation process would be to address one of the largest unknowns in terms
of decision-making for engineers carrying out life-cycle cost/benefit evaluations and to facilitate the
sharing of lining performance data among municipalities in a systematic and transferable manner.
Evaluating rehabilitation technologies that have already been in service for a significant length of time
could also provide data that could be used immediately by other municipalities (e.g., what
properties/defects are critical; what accelerates deterioration) and could establish benchmarks for vendors
VI
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against which they can improve their products (i.e., it could become a driver for achieving excellence). It
is an opportune time for such a concerted push in terms of evaluation because there has been a significant
time in service for many technologies and there is a continued strong investment in the use of the
technologies across the U.S.
vn
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CONTENTS
DISCLAIMER II
ABSTRACT Ill
ACKNOWLEDGMENTS IV
EXECUTIVE SUMMARY V
CONTENTS VIII
APPENDICES XII
FIGURES XII
TABLES XIV
ABBREVIATIONS AND ACRONYMS XVI
1.0: INTRODUCTION 1
2.0: CIPP TECHNOLOGY DEVELOPMENT 4
3.0: DEVELOPMENT OF CIPP EVALUATION METHODOLOGY 15
4.0: CITY OF DENVER RETROSPECTIVE STUDY 23
5.0: CITY OF COLUMBUS RETROSPECTIVE STUDY 63
6.0: REVIEW AND COMPARISON ACROSS THE FOUR SITES 93
7.0: RECOMMENDED TEST PROTOCOL FOR FUTURE USE 103
8.0: REPORT ON INTERNATIONAL SCAN ACTIVITIES AND FINDINGS 108
9.0: SUMMARY AND RECOMMENDATIONS 126
10.0: REFERENCES 130
1.0: INTRODUCTION 1
1.1 Organization of Protocol Development and Field Studies 2
1.2 Organization of the Report 3
2.0: CIPP TECHNOLOGY DEVELOPMENT 4
2.1 Introduction 4
2.2 Cured-in-Place Pipe 5
2.2.1 Historical and Commercial Background 5
2.2.2 The CIPP Process 6
2.2.3 Installation Method: Inversion or Pull-In 9
2.2.4 Tube Construction 10
2.2.5 Choice of Resins for CIPP 10
2.2.6 Thermal Curing Process 11
2.2.7 Ultraviolet Light Cured Liners 12
2.2.8 Emerging and Novel CIPP Technologies 12
2.3 North American Experience with CIPP 13
2.3.1 Experiences and Case Histories 13
2.3.2 Testing and QA/QC 13
2.3.3 Environmental Issues 14
3.0: DEVELOPMENT OF CIPP EVALUATION METHODOLOGY 15
3.1 Review of Potential Alternatives 15
3.2 Goals for a Specific Retrospective Evaluation Using the Draft Protocols 16
3.3 Preliminary Outline of Anticipated Protocol for CIPP Evaluation 16
3.3.1 Identification of Municipal Partners 16
3.3.2 Identification of Segments for Evaluation 17
3.3.3 Availability of Historical Data 17
3.3.4 Retrieval of Field Samples (Dig up and Replace Sample) 18
3.3.5 In-Situ Evaluation 18
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3.3.6 Evaluation of Results 19
3.4 Test Plans and Quality Assurance 19
3.4.1 Additional Testing Concepts 22
4.0: CITY OF DENVER RETROSPECTIVE STUDY 23
4.1 Introduction 23
4.2 Site 1: 25-year Old CIPP Liner in an 8-in. Clay Pipe 23
4.2.1 Host Pipe and Liner Information 23
4.2.2 Timeline for Fieldwork 24
4.2.3 Visual Inspection of the Liner 25
4.2.4 Locations of Soil Samples 26
4.2.5 Analysis of Soil Samples 26
4.2.5.1 Particle Size Distribution 26
4.2.5.2 Soil Specific Gravity and Absorption 26
4.2.5.3 Soil Moisture Content 26
4.2.6 Measurement of Acidity and Alkalinity, pH 28
4.2.7 Annular Gap 28
4.2.8 Liner Thickness 29
4.2.9 Specific Gravity and Porosity 30
4.2.10 Ovality 30
4.2.11 Flexural Testing and Tensile Testing 31
4.2.12 Buckling Test 37
4.2.13 Shore D Hardness 41
4.2.14 Barcol Hardness 41
4.2.15 Raman Spectroscopy 44
4.2.16 Differential Scanning Calorimetry (DSC) 44
4.2.17 CCTV Inspection of Area Sewers for Denver 8-in. Site 46
4.3 Site 2: 48 in. Equivalent Diameter Egg-Shaped Brick Sewer 47
4.3.1 Host Pipe and Liner Information 47
4.3.2 Sample Removed and Tested in 1995 47
4.3.3 Sample Retrieval in 2010 48
4.3.4 Annular Gap 48
4.3.5 Liner Thickness 48
4.3.5.1 Downstream Sample 48
4.3.5.2 Upstream Sample 49
4.3.6 Specific Gravity and Porosity 50
4.3.6.1 Introduction 50
4.3.6.2 Downstream Sample 51
4.3.6.3 Upstream Sample 51
4.3.7 Flexural Testing 51
4.3.7.1 Downstream Sample 51
4.3.7.2 Upstream Sample 53
4.3.8 Tensile Testing 55
4.3.8.1 Downstream Sample 55
4.3.8.2 Upstream Sample 57
4.3.9 Shore D Hardness 57
4.3.9.1 Introduction 57
4.3.9.2 Downstream Sample 58
4.3.9.3 Upstream Sample 58
4.3.10 Barcol Hardness 59
4.3.10.1 Downstream Sample 59
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4.3.10.2 Upstream Sample 60
4.3.11 Raman Spectroscopy 60
4.3.11.1 Introduction 60
4.3.11.2 Downstream Sample 61
4.3.11.3 Upstream Sample 61
4.3.12 Comparison of 1995 and 2010 Test Results 62
5.0: CITY OF COLUMBUS RETROSPECTIVE STUDY 63
5.1 Introduction 63
5.2 Site 1: 5-year Old CIPP Liner in 8-in. Clay Pipe 63
5.2.1 Host Pipe and Liner Information 63
5.2.2 Timeline for Fieldwork 64
5.2.3 Visual Inspection of Liner 65
5.2.4 Locations of Soil Samples 66
5.2.5 Analysis of Soil Samples 66
5.2.5.1 Particle Size Distribution 66
5.2.5.2 Soil Specific Gravity and Absorption 67
5.2.5.3 Soil Moisture Content 68
5.2.6 Measurement of Acidity and Alkalinity, pH 68
5.2.7 Wastewater Analysis 69
5.2.8 Annular Gap 69
5.2.9 Liner Thickness 70
5.2.10 Specific Gravity and Porosity 71
5.2.11 Ovality 71
5.2.12 Flexural Testing 73
5.2.13 Tensile Testing 76
5.2.14 Comparison of Measured Values and QC Sample/Design Values 78
5.2.15 Buckling Test 79
5.2.16 Shore D Hardness 81
5.2.17 Barcol Hardness 81
5.2.18 Raman Spectroscopy 84
5.3 Site 2: 36-in. Brick Sewer 84
5.3.1 Host Pipe and Liner Information 84
5.3.2 Sample Recovery 84
5.3.3 Visual Inspection of Liner 85
5.3.4 Wastewater Analysis 86
5.3.5 Annular Gap 86
5.3.6 Liner Thickness 86
5.3.6.1 Ultrasound Testing 86
5.3.6.2 Field Measurements 86
5.3.6.3 Laboratory Measurements 88
5.3.7 Specific Gravity and Porosity 88
5.3.8 Flexural Testing 88
5.3.9 Tensile Testing 90
5.3.10 Shore D Hardness 90
5.3.11 Barcol Hardness 91
5.3.12 Raman Spectroscopy 92
6.0: REVIEW AND COMPARISON ACROSS THE FOUR SITES 93
6.1 Introduction 93
6.2 Summary for City of Denver Evaluations 93
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6.3 Summary for City of Columbus Evaluations 94
6.4 Summary of Data and Observations for All Sites 95
6.4.1 Visual Observations 95
6.4.2 Annular Gap 95
6.4.3 Liner Thickness 95
6.4.4 Specific Gravity and Porosity 96
6.4.5 Strength and Flexural Modulus 98
6.4.6 Buckling Tests 100
6.4.7 Surface Hardness Tests 100
6.4.8 Raman Spectroscopy and Other Polymer Testing 101
6.5 Current Findings 101
6.5.1 Material Degradation 101
6.5.2 Conformance of Sampled Liners to Original Specifications 101
6.5.3 Prognosis for Remaining Life 102
6.5.4 Testing Issues 102
7.0: RECOMMENDED TEST PROTOCOL FOR FUTURE USE 103
7.1 Overview of Protocol Implications 103
7.2 Fieldwork Costs 103
7.2.1 City of Denver Costs 103
7.2.2 City of Columbus Costs 104
7.3 Developing an Extended Program for Retrospective Evaluation 104
7.4 Aggregating National Data on Liner Performance 105
8.0: REPORT ON INTERNATIONAL SCAN ACTIVITIES AND FINDINGS 108
8.1 Introduction 108
8.2 Rehabilitation Experience 108
8.3 Specifications and Design 110
8.4 Preparation and Supervision Ill
8.5 Verification and Testing 112
8.6 Utilities' Views on Effectiveness of Sewer Rehabilitation 114
8.6.1 Based on Long-Term Samples 114
8.6.2 Based on CCTV Inspections 115
8.6.3 Based on General Experience 115
8.7 CIPP Use and Testing in Japan 117
8.8 Approach to Retrospective Evaluation in Quebec 123
9.0: SUMMARY AND RECOMMENDATIONS 126
9.1 Summary 126
9.1.1 Tasks to Date 126
9.1.2 CIPP Liner Condition Findings to Date 126
9.1.3 Initial Findings on Value of Various Physical Testing Approaches 127
9.1.3.1 Soil Conditions 127
9.1.3.2 Visual Inspection 127
9.1.3.3 Thickness and Annular Gap 127
9.1.3.4 Flexural and Tensile Testing 128
9.1.3.5 Surface Hardness Testing 128
9.1.3.6 Material Composition Testing 128
9.1.4 Recommendations for National Data Compilation and Management 128
9.2 Recommendations for Future Work 129
9.2.1 Recommendations for Continued Retrospective Evaluations on Retrieved Samples . 129
XI
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9.2.2 Recommendations for Development and Calibration of NDT Protocols 129
10.0: REFERENCES 130
APPENDICES
APPENDIX A: List of Test Standards Referenced
APPENDIX B: Investigation of Ultrasonic Measurements for CIPP Thickness
APPENDIX C: International Study Interview Reports
APPENDIX D: Mercury Penetration Porosity Test Reports
FIGURES
Figure 2-1. Rehabilitation Approaches for Sewer Mainlines 4
Figure 2-2. CIPP Installation Options: Liner Pull-in (Left) and Liner Inversion (Right) 8
Figure 2-3. Summary of Common CIPP Technologies 9
Figure 2-4. UV Light Curing Train 12
Figure 4-1. Images of the Recovered Specimen 25
Figure 4-2. Images of the Inner Surface of the 25-year Old, 6-ft Long CIPP Liner Section 25
Figure 4-3. Location of Soil Sample Collection Place (Denver 8-in Site) 26
Figure 4-4. Soil Grain Size Distribution (Denver 8-in. Site) 27
Figure 4-5. Measurement of pH Using a pH Meter 28
Figure 4-6. Average Thickness at Different Locations on the Liner 29
Figure 4-7. Profile Plotter Setup 30
Figure 4-8. Ovality of the Denver 8-in. Liner 31
Figure 4-9. Liner Specimens - Bending (Left) and Tensile (Right) (Denver 8-in. Liner) 32
Figure 4-10. Flexural Testing in Accordance with ASTM D790 32
Figure 4-11. Tensile Testing Specimens Before (Left) and After the Test (Right) 32
Figure 4-12. Stress-Strain Curves from Flexural Testing of Specimens (Denver 8-in. Liner) 34
Figure 4-13. Stress-Strain Curves from Tensile Testing of Specimens (Denver 8-in. Liner) 36
Figure 4-14. Machined Mechanical Tube (Left) and a Threaded Hole on the Tube (Right) 37
Figure 4-15. Liner Inside the Pipe and Beveling of the Liner 37
Figure 4-17. Experimental Setup Showing the Threaded Rod 37
Figure 4-16. Drawing of a Pressure Cap 38
Figure 4-18. Pressure Gage and Pressure Application Installed on the System 39
Figure 4-19. Nitrogen Gas Pressure Bladder System for Supplying the Test Pressure 39
Figure 4-20. Profile Plotting - LVDT Rotating on the Inner Circumference 39
Figure 4-21. Pressure on the Liner at Intervals During the Test 40
Figure 4-22. Localized Leak on the Liner - Green Spots Due to Green Food Color 40
Figure 4-23. Shore D Hardness Readings for the Liner's Inner and Outer Surfaces (Denver 8-in.
Liner) 42
Figure 4-24. Barcol Hardness Readings forthe Liner's Inner and Outer Surfaces 43
Figure 4-25. Raman Spectra (Denver 8-in. Liner) 44
Figure 4-26. Layout and 2010 Sample Locations forthe Denver 48-in. Liner 47
Figure 4-27. Images of the Recovered Samples from the Denver 48-in. Liner 48
Figure 4-28. Thickness for Denver 48-in. Downstream Sample 49
Figure 4-29. Thickness for Denver 48-in. Upstream Sample 49
Figure 4-30. Weighing Scale, Model Mettler PM200 50
Figure 4-31. Wire Basket and Thermometer 50
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Figure 4-32. ASTM D792 Setup 50
Figure 4-33. Flexural Test in Accordance with ASTM D790 51
Figure 4-34. Flexural Stress-Strain Curves for Denver 48-in. Downstream Sample 53
Figure 4-35. Flexural Stress-Strain Curves for the Denver 48-in. Upstream Liner (Set 1) 54
Figure 4-36. Flexural Stress-Strain Curves for Denver 48-in. Upstream Liner (Set 2) 55
Figure 4-37. Tensile Specimens for Denver 48-in. Upstream Sample: Before the Test (Left) and
Following the Test (Right) 56
Figure 4-38. Stress-Strain Curves from Tensile Testing for Denver 48-in. Downstream Sample 56
Figure 4-39. Stress-Strain Curves from Tensile Testing of Denver 48-in. Upstream Samples 57
Figure 4-40. Shore D Hardness for Denver 48-in. Downstream Sample 58
Figure 4-41. Shore D Hardness for Denver 48-in. Upstream Sample 58
Figure 4-42. Original Outer Surface (Denver 48-in. Downstream Sample) 59
Figure 4-43. Smoothed Outer Surface (Top Row) and Inner Surface (Bottom Row) (Denver 48-in.
Downstream Sample) 59
Figure 4-44. Barcol Hardness Tester, Taking a Measurement 59
Figure 4-45. Barcol Hardness Test Setup 59
Figure 4-46. Barcol Hardness of Denver 48-in. Downstream Sample 60
Figure 4-47. Barcol Hardness of Denver 48-in. Upstream Sample 60
Figure 4-48. Raman Spectroscopy Plots (Denver 48-in. Downstream) 61
Figure 4-49. Raman Spectroscopy Plots (Denver 48-in. Upstream) 61
Figure 5-1. Images of the Recovered Specimen (Columbus 8-in. Liner) 65
Figure 5-2. Images of the Inner Surface of the 5-year Old Columbus 8-in. Liner 65
Figure 5-3. Location of Soil Samples (Columbus 8-in. Site) 66
Figure 5-4. Collected In-Situ Soil Samples (Columbus 8-in. Site) 66
Figure 5-5. Grain Size Distribution of Soil Samples (Columbus 8-in. Liner Site) 67
Figure 5-6. Measurement of pH (Columbus 8-in. Soil Samples) 68
Figure 5-7. Histogram of Annular Gap Measurements (Columbus 8-in. Liner) 70
Figure 5-8. Average Thickness at Different Locations (Columbus 8-in. Liner) 71
Figure 5-9. Electronic Level Used to Position Horizontally the Pipe (Left) and the Profile Plotter
(Right) 71
Figure 5-10. Profile Plotting with LVDT Rotating on the Inner Circumference: Close Up (Left)
and Complete View (Right) 72
Figure 5-11. Profile Plot of Steel Host Pipe and Liner Before and After the Buckling Test
(Columbus 8-in. Liner) 72
Figure 5-12. Flexural Test Specimens (ASTM D790): Before Test (Left) and After Test (Right) 73
Figure 5-13. Flexural Testing in Accordance with ASTM D790 73
Figure 5-14. Flexural Stress-Strain Curves for Crown, Spring Line, and Invert Samples (Columbus
8-in. Liner) 75
Figure 5-15. Tensile Specimens for Columbus 8-in. Liner: Before the Test (Left) and Following
the Test (Right) 76
Figure 5-16. Tensile Stress-Strain Curves for Crown, Spring Line and Invert (Columbus 8-in.) 77
Figure 5-17. Drawing ofthe Pressure Cap Used 79
Figure 5-18. Placement of Liner Inside the Host Pipe 79
Figure 5-19. Experimental Setup 79
Figure 5-20. High Pressure Pump 80
Figure 5-21. Pressure Gauges Connected on the Tube 80
Figure 5-22. Pressure on the Liner During Buckling Test 80
Figure 5-23. Pressure Gauge Showing Pressure of 40 psi Applied on the Liner 80
Figure 5-24. Localized Leak on the Liner- Green Spots Due to Green Food Color 81
Figure 5-25. Shore D Hardness Readings on Inner and Outer Surfaces (Columbus 8-in. Liner) 82
Figure 5-26. Barcol Hardness Readings on Inner and Outer Surfaces (Columbus 8-in. Liner) 83
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Figure 5-27. Raman Spectra for the Columbus 8-in. Liner 84
Figure 5-28. Cutting Out the Columbus 36-in. Liner Sample 85
Figure 5-29. The Exhumed Sample (Columbus 36-in. Liner) 85
Figure 5-30. Images of the Recovered Columbus 36-in. Specimen 85
Figure 5-31. Annular Space Measurements Around the Sample Removal Area (Columbus 36-in.
Liner) 86
Figure 5-32. Ultrasonic Testing for Measuring Liner Thickness in the Field 87
Figure 5-33. Caliper Measurements of Columbus 36-in. Sample 87
Figure 5-34. Field Measurements of Thickness for Columbus 36-in. Liner 87
Figure 5-35. Laboratory Measurements of Thickness for the Columbus 36-in. Liner 88
Figure 5-36. Flexural Stress-Strain Curves (Columbus 8-in. Liner) 89
Figure 5-37. Tensile Stress-Strain Curves (Columbus 36-in. Liner) 90
Figure 5-38. Shore D Hardness of Columbus 36-in. Liner Sample 91
Figure 5-39. Barcol Hardness Readings on Inner and Outer Surfaces (Columbus 36-in. Liner) 91
Figure 5-40. Raman Spectroscopy Plots (Columbus 36-in. Liner) 92
Figure 8-1. Total Number of Sewer Collapses per Annum 119
Figure 8-2. Rate of Collapses by Pipe Age 119
Figure 8-3. Annual Rehabilitation Construction 1986-2009 121
Figure 8-4. Installations Categorized by Method and Diameter for 2009 122
TABLES
Table 2-1. CIPP Products Available in the U.S. in 1990 and Their Characteristics 6
Table 2-2. Key ASTM Standards Covering CIPP Installations 7
Table 3-1. Potential Evaluation Strategies for Liner Deterioration 15
Table 3-2. Field Measurement Plans 20
Table 3-3. Laboratory Evaluation and Measurement Plans 21
Table 3-4. Additional Testing/Evaluation Concepts Considered 22
Table 4-1. Designation of Collected Soil Samples for Denver 8-in. Site 26
Table 4-2. Soil Specific Gravity and Absorption (Denver 8-in. Site) 27
Table 4-3. Soil Moisture Content (Denver 8-in. Site) 27
Table 4-4. Soil pH at Designated Locations and Sewage pH (Denver 8-in. Site) 28
Table 4-5. Denver 8-in. Liner Annular Gap Measurements 29
Table 4-6. Marking of Specimens (Denver 8-in. Liner) 32
Table 4-7. Results from Flexural Testing (Denver 8-in. Liner) 33
Table 4-8. Results from Tensile Testing (Denver 8-in. Liner) 33
Table 4-9. Comparison of Test Data from TTC and Insituform 35
Table 4-10. Perkin Elmer Diamond DSC Testing Parameters 45
Table 4-11. Gravimetric Data for DSC Test (Denver 8-in. Liner) 45
Table 4-12. Sample Tg Determination (Denver 8-in. Liner) 46
Table 4-13. Historic Sampling Results for the CIPP Liner Tested in 1995 (Denver 48-in. Liner) 48
Table 4-14. Geometric Data for Flexural Test Specimens (Denver 48-in. Downstream Sample) 52
Table 4-15. Flexural Test Results for Denver 48-in. Downstream Sample 52
Table 4-16. Geometric Data for Flexural Test Specimens for Denver 48-in. Upstream Sample 53
Table 4-17. Flexural Test Results for Denver 48-in. Upstream Samples (Set 1) 54
Table 4-18. Flexural Test Results for Denver 48-in. Upstream Samples (Set 2) 55
Table 4-19. Tensile Test Results for Denver 48-in. Downstream Sample 56
Table 4-20. Tensile Test Results for Denver 48-in. Upstream Sample 57
Table 4-21. Comparison of 1995 and 2010 Test Results for the Denver 48-in. Liner 62
Table 5-1. Designation of Collected Soil Samples (Columbus 8-in. Site) 66
xiv
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Table 5-2. Soil Specific Gravity and Absorption Results (Columbus 8-in. Site) 67
Table 5-3. Soil Moisture Content Results (Columbus 8-in. Site) 68
Table 5-4. Soil pHat Designated Locations and Sewage pH (Columbus 8-in. Site) 69
Table 5-5. Results of Wastewater Analysis (Columbus 8-in. Site) 69
Table 5-6. Annular Gap Measurements (Columbus 8-in. Liner) 70
Table 5-7. Geometric Data for Flexural Test Specimens for Columbus 8-in. Liner 74
Table 5-8. Flexural Test Results for Columbus 8-in. Liner 74
Table 5-9. Summary of Results from Tensile Testing for Columbus 8-in. Liner 76
Table 5-10. Test Data from 2005 CIPP (as-installed) Sample (Columbus 8-in. Liner) 78
Table 5-11. Summary of 2010 Retrospective Data (Columbus 8-in. Liner) 78
Table 5-12. Results of Wastewater Analysis for Columbus 36-in. Liner 86
Table 5-13. Geometric Data for Flexural Test Specimens for Columbus 36-in. Liner 89
Table 5-14. Flexural Test Results for Columbus 36-in. Liner 89
Table 5-15. Tensile Test Results for Columbus 36-in. Liner 90
Table 6-1. Summary of Thickness Measurements for All Samples 95
Table 6-2. Compilation of Porosity Test Results 96
Table 6-3. Comparison of Density Data 97
Table 6-4. Comparison of Strength, Modulus and Elongation Values for All Liner Samples 98
Table 6-5. Summary of Hardness Values 100
Table 7-1. Field Work Costs for Sample Retrieval in Denver 104
Table 7-2. City of Columbus Costs 104
Table 7-3. Overall Structure for a National Retrospective Evaluation Database 106
Table 8-1. Utilities or Organizations Participating in this Review 108
Table 8-2. CIPP and Other Rehabilitation Methods 109
Table 8-3. Current Usage of Rehabilitation Methods 109
Table 8-4. Usage of Other CIPP Materials 110
Table 8-5. Rehabilitation Specifications Ill
Table 8-6. Type Testing Required in Specifications Ill
Table 8-7. Preparation and Supervision of CIPP Works 112
Table 8-8. Post-Works Inspection and In-Situ Testing 112
Table 8-9. Process Verification Testing Undertaken 113
Table 8-10. Warranty Periods on Rehabilitation Works 114
Table 8-11. Test Results from First CIPP Installation 114
Table 8-12. Findings from Retrospective Samples of CIPP in Singapore 115
Table 8-13. JSWA Condition Assessment Method 120
Table 8-14. JSWA Ranking System 120
xv
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ABBREVIATIONS AND ACRONYMS
AMP Asset Management Period
ASTEE Association Scientifique et Technique pour 1'Eau et 1'Environnement
ASTM American Society for Testing and Materials
ATH alumina trihydroxide
a.u. arbitrary units
ATV Abwassertechnische Vereinigung (German Wastewater Technical Association)
BW Brisbane Water
CAC Communaute dAgglomeration de Chartres
CAHB Communaute dAgglomeration Les Hauts-de-Bievre
CEN Comite Europeen de Normalisation (European Committee for Standardization)
CERIU Centre d'Expertise et de Recherche en Infrastructures Urbaines
CCTV closed-circuit television
CIPP cured-in-place pipe
DAQ data acquisition system
DEFRA Department of the Environment, Food and Rural Affairs
DRO diesel range organics
DSC differential scanning calorimetry
DVGW Deutscher Verein des Gas- und Wasserfaches e.V. - Technisch-wissenschaftlicher Verein
(German Technical and Scientific Association for Gas and Water)
DWI Drinking Water Inspectorate
EA U.K. Environment Agency
EPA U.S. Environmental Protection Agency
FTIR Fourier transform infrared
GIS geographic information system
GRO Gasoline Range Organics
GRP Glass Reinforced Plastic
GS Gottingen Stadtentwasserung
I/I infiltration and inflow
IKT Institut fur Unterirdische Infrastruktur gGmbH (Institute for Underground Infrastructure)
ISTT International Society for Trenchless Technology
JASCOMA Japan Sewer Collection Maintenance Association
JIWET Japan Institute of Wastewater Technology
JPRQAA Japan Pipe Rehabilitation Quality Assurance Association
JSWA Japan Sewerage Works Agency
LVDT linear variable displacement transducer
MLIT Ministry of Land, Infrastructure and Construction (Japan)
NASTT North American Society for Trenchless Technology
xvi
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NDT non-destructive testing
NRMRL National Risk Management Research Laboratory
OD oven dry
OFWAT Office of Water Services
PE polyethylene
psi pounds per square inch
psia pounds per square inch absolute
PUB Public Utilities Board (Singapore)
PUBC PUB Consultants Private Limited
PVC polyvinyl chloride
QA quality assurance
QAPP Quality Assurance Protocol Plan
QC quality control
QUU Queensland Urban Utilities
SgSTT Singapore Society for Trenchless Technology
SOP standard operating procedure
SPR spiral pipe renewal
SRM Sewer Rehabilitation Manual (U.K.)
SSD saturated surface dry
STW Severn Trent Water
SW Sydney Water
TBL Technische Betriebe der Stadt Leverkusen
TBPB tert-butyl peroxybenzoate peroxide
Tg glass transition temperature
TGA thermo-gravimetric analysis
TO task order
TPH total petroleum hydrocarbons
TTC Trenchless Technology Center
TW Thames Water
TWA Thames Water Authority
UTM Universal Testing Machine
UV ultraviolet
VCP vitrified clay pipe
VOC volatile organic compound
WEFTEC Water Environment Federation Technical Exhibition and Conference
WIS Water Industry Specifications (U.K.)
WRc Water Research Centre (U.K.)
XVII
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1.0: INTRODUCTION
This report forms part of a project funded by the U.S. Environmental Protection Agency (EPA) to study
and support technology development for the rehabilitation of water distribution and wastewater collection
systems. During the early stages of this project, the need for a quantitative, retrospective evaluation of the
performance of pipe rehabilitation systems emerged. Pipe rehabilitation and trenchless pipe replacement
technologies have seen a steadily increasing use over the past 30 to 40 years and represent an increasing
proportion of the approximately $25 billion annual expenditure on operations and maintenance of the
nation's water and wastewater infrastructure (EPA, 2002). Despite the massive public investment
represented by the use of these technologies, there has been little formal and quantitative evaluation of
whether they are performing as expected and whether rehabilitation is indeed cost-effective compared to
replacement. The need for such information was reinforced by the participants at an international
technology forum held as part of the project activities in September 2008. It was noted at the forum that
the City of Montreal and a number of cities in Germany have already engaged in efforts to revisit
previous rehabilitation projects to characterize their level of in-service performance to assess any
evidence of deterioration (Sterling et al., 2009). Information collected on these and other international
experiences with cured-in-place pipe (CIPP) liners are included in this report.
The major reasons for 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 some hard
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 nearly 30 years in the U.S. and 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.
The outcome of an effective evaluation would be to address one of the largest unknowns in terms of
decision-making for engineers carrying out life-cycle cost/benefit evaluations and to facilitate the sharing
of lining performance data among municipalities in a systematic and transferable manner. 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 could provide data that could be used immediately by other municipalities (e.g.,
what properties/defects are critical; what accelerates deterioration) and could establish benchmarks for
vendors against which they can improve their products (i.e., it could become a driver for achieving
excellence).
It is an opportune time for such a concerted push in terms of evaluation because there has been a
significant time in service for many technologies and there is a continued strong investment in the use of
the technologies across the U.S.
While the long-term goal of the retrospective evaluation effort is to provide significant and credible
feedback on performance to the system owners and the engineers who specify rehabilitation and
replacement, a few isolated evaluations of projects with a variety of existing and service conditions
-------
cannot provide statistically significant data. Thus, the goals for the effort within this project are: to draw
attention to the need for this type of evaluation and to develop evaluation protocols that are technically
and financially feasible for carrying out evaluations of the main rehabilitation and trenchless replacement
technologies. The protocol should produce useful results at a cost that municipalities will be willing to
pay to participate in the data collection. The subsequent drive will be to encourage municipalities and
other system owners to conduct their own evaluations and then to contribute their data to a common
database where the results can be aggregated on a national basis. The initial project focuses on CIPP
liners because they were the first trenchless liners (other than conventional slipliners) used in pipe
rehabilitation and because they hold the largest market share within relining technologies. It is intended
to use the experiences derived from the evaluation of CIPP liners described in this report to develop
similar technology-appropriate protocols for other rehabilitation systems.
1.1 Organization of Protocol Development and Field Studies
The research team for the retrospective evaluation effort was comprised of Battelle as Project Manager
with the Trenchless Technology Center (TTC) at Louisiana Tech University taking the lead in developing
the test protocol and carrying out the liner testing. Jason Consultants was responsible for carrying out a
review of what other cities around the world are doing with respect to long-term evaluations of their
lining programs. Jason Consultants also assisted with field inspections and evaluation of test results.
The project stages generally followed the progression of activities outlined below:
• A comprehensive list of field investigations and laboratory testing was developed that could
be used to evaluate the current condition of a CIPP liner and provide information on its
potential longevity.
• A written summary of the proposed liner evaluation protocol and its expected benefits was
prepared that could be used in discussions with interested municipalities.
• Municipalities were identified that would be interested in assisting with a retrospective
evaluation of previously installed CIPP liners and that had CIPP liners with as many years of
service as possible.
• Detailed discussions were entered into with the identified municipalities to discuss their
participation in the study and the division of responsibilities and costs for the field retrieval of
samples. To reduce project costs, it was planned to retrieve samples from two distinct sites at
each municipality.
• 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 tests carried out on the liners were evaluated as to the nature and extent that they provide
information regarding the liner's condition relative to its condition immediately following
installation and also for their cost-effectiveness in a more widespread liner evaluation
program.
• Conclusions from the initial testing were developed and recommendations were formed as to
a suitable retrospective evaluation protocol for wider use in the U.S.
This work was carried out in parallel with a broader set of interviews with municipalities and sewer
agencies internationally to determine whether any international efforts were underway in terms of
retrospective evaluations and, if so, what types of evaluation and testing were being used.
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1.2 Organization of the Report
Following the introduction to the concept and development of the retrospective evaluation effort provided
in this Section, the main body of the report focuses on CIPP liners which have been the initial target of
the retrospective study. Section 2 provides a review of the development and use of CIPP as a
rehabilitation technology. Section 3 discusses the development of the draft evaluation protocol that was
discussed with the two cities that participated in this initial study. Sections 4 and 5 provide the detailed
studies carried out on two separate liners in each city. Section 6 compares the results obtained across the
four liners and Section 7 discusses the implications of the sample retrieval process and testing used in
these pilot studies on a suitable protocol for wider implementation across the U.S. The results of the
international scan are reported in Section 8 and the overall summary and recommendations for further
work are provided in Section 9.
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2.0: CIPP TECHNOLOGY DEVELOPMENT
2.1
Introduction
CIPP technology is one of a family of trenchless rehabilitation methods that allows the renewal of a
buried pipe without the full excavation of the pipe from the ground surface. Such rehabilitation methods
applied to sewer mainlines include the use of CIPP, close-fit linings, grout in place, spiral-wound linings,
panel linings, spray-on/spin-cast linings, and chemical grouting as illustrated in Figure 2-1. Pipe repair
(e.g., repair sleeves) and replacement methods (e.g., sliplining and pipe bursting) may also be carried out
using trenchless technology approaches. Further information on these various repair, replacement, and
rehabilitation technologies can be found in a companion EPA report (Sterling et al., 2010).
1
C,PP ^|
Thermal Cure
-I UV Cure
Unreinforced
•4 Reinforced
Hybrid
1
Close Fit
•J Fold-and-Form
Symmetrical
Reduction
Symmetrical
Compression
Symmetrical
Expansion
1
Grout-in-Place 1
Preformed
Shapes
Spiral Wound
Spiral Wound 1
Circular
Non-circular
fc- 1
1
Panel Linings I
J Full Ring
Partial
1
Spray/Spincast 1
Applied
4 Cementitious
Epoxy
•1 Poly u ret hane
•1 Potyurea
i
Grouting
•1 Test and Seal
Flood Grouting 1
Figure 2-1. Rehabilitation Approaches for Sewer Mainlines
Some of these rehabilitation and trenchless replacement technologies vary significantly in their
applicability to various aspects of host pipe condition. Examples of typical issues are:
• Extent of cleaning required (e.g., high level of cleaning required for spray coatings and close-
fit lining systems; low level needed for pipe bursting)
• Sensitivity of method to minor variations in pipe's internal diameter
• Adaptability of the method to cope with pipe-diameter changes within a rehabilitation
segment.
Technologies also vary significantly in their requirements for sewage flow interruption or bypassing of
the sewer line. The significance of this requirement increases as the sewer diameter increases, reflecting
larger and more continuous sewage flows and more critical backup requirements for the bypass
operations.
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Some sections of a sewer system may be in good overall structural condition, but have leaking cracks or
joints that allow excessive infiltration and inflow (I/I) into the system. Other pipes may need partial or
complete upgrading of the structural condition of pipe to withstand internal pressures, or external soil and
groundwater pressures.
The focus of this initial retrospective evaluation 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. with
liners that have been in service for up to 30 years in the U.S. and nearly 40 years in the U.K. A more
detailed description of CIPP rehabilitation and related research and testing as related to its use for the
rehabilitation of gravity sewer mainlines follows in the rest of this section.
2.2 Cured-in-Place Pipe
2.2.1 Historical and Commercial Background. 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 x 2 ft (1,175 mm x 610
mm). The work was carried out by inventor Eric Wood supported by entrepreneurs Doug Chick and
Brian Chandler and following this successful trial, they registered the company Insituform Pipes and
Structures, Ltd., and proceeded to market the technology and make improvements in the materials,
preparation, and application of the technology (Downey, 2010). It should be noted that this first
installation was a pull-in-and-inflate liner - inversion was not possible until coated felt was used in 1973.
The name and structure of the Insituform family of companies have changed over the years and, over
time, other companies have entered the market with similar and competitive technologies.
Eric Wood applied for the first patent on the CIPP process on August 21, 1970 in the U.K. and was
granted his first U.S. Patent on the process (U.S. Patent No. 4009063) on February 22, 1977. After
granting licenses to British contractors to begin using this new process to rehabilitate sewers in England,
Insituform expanded its business in 1976 by granting licenses to contractors in mainland Europe and in
Australia. In 1976, Wood began licensing his process to contractors in North America. In 1994,
however, the patent for Insituform's inversion process expired and this resulted in new competition in the
trenchless rehabilitation industry (Rose and Jin, 2006). Another important patent related to the process
concerned vacuum impregnation. The U.S. version of this patent was granted on December 28, 1982
(U.S. Patent No. 4366012). The patent expired on February 5, 2001. U.S. patents on various aspects of
the CIPP process are still being sought and granted, e.g., U.S. Patent Nos. 5798013 and 6679966 issued in
1998 and 2004 related to the Brandenburger CIPP lining process and U.S. Patent No. 6942426 related to
control of the thermal curing process granted to Kampbell and Cuba in 2005. Insituform has continued to
file a variety of patents related to CIPP. These include U.S. Patent No. 4135958, granted on January 23,
1979, which includes a discussion of the light curing of liners and "Method for Remote Lining of Side
Connections" (U.S. Patent No. 4434115) issued on February 28, 1984.
In 1976, the first Insituform® liner was installed in the U.S. in a 12-in.-diameter line in Fresno, California.
Since then, approximately 19,000 miles (100 million ft) of CIPP liner have been installed by U.S.-based
Insituform contractors (Osborn, 2011). The original installations involved an inverted resin-felt
composite liner impregnated with polyester resin and cured with hot water. Other companies also started
installing CIPP liners in the U.S. through the 1980s and 1990s. These include the Inliner® system which
was first introduced in 1986 with over 9 million ft installed since then. Other longstanding liner suppliers
that are still operating include National Liner® and Masterliner®.
Other early municipal users of CIPP in the U.S. included the Washington Suburban Sanitary Commission
(from 1978) (Hannan, 1990) and the City and County of Denver (from 1984) (Barsoom, 1993). St. Louis,
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Houston, Baltimore, Little Rock, Memphis, and Indianapolis were among other cities that established
early CIPP rehabilitation programs (Iseley, 2011). By 1990, four liner systems were reported to be
available in the U.S. (see Table 2-1).
Table 2-1. CIPP Products Available in the U.S. in 1990 and Their Characteristics
(Hannan, 1990)
Liner
Parameter
Insertion
Materials
Curing
Process
Product
Insituform
Inversion using
water head
Non-woven tube
materials and
thermoset resin
Circulating hot
water
Paltem
Inversion using air
pressure
Woven and
non-woven
tube materials and
thermoset resin
Circulating hot
steam
In-Liner
Winched into
place
Non-woven tube
materials and
thermoset resin
Circulating hot
water
Insta-Pipe
Floated and winched
into place
Woven and non-woven
tube materials & epoxy
thermoset resin
Circulating hot air
As the original patents on key aspects of the CIPP process expired, the breadth of competition increased.
Overall, since 1971, it is estimated that about 40,000 miles (210 million ft) of CIPP liners have been
installed worldwide. It is by far the leading method for rehabilitating gravity sewers.
2.2.2 The CIPP Process. A CIPP project involves a variety of investigative, planning, and
execution phases. Once a line has been identified as needing rehabilitation or replacement, the
characteristics of the line and the problems experienced will determine if the CIPP process is a suitable
candidate for replacement. 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 a variety of published sources on rehabilitation technologies and in the
literature 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).
Prior to the relining work, the existing host pipe will be carefully examined (typically using a closed-
circuit television [CCTV] camera inspection) and any necessary additional measurements (such as pipe
diameter) are collected. Data on pipe depth, soil type, and groundwater conditions will also be gathered.
Based on this 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 is required.
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• 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 key American Society for Testing and Materials (ASTM) standards pertaining to different types of
CIPP liner installation are shown in Table 2-2. The structural requirements of the liner are designed in all
of the standards using the procedures specified in ASTM F1216. This is based primarily on 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 its short-term buckling resistance. This is accounted for in the
F1216 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. References to a selection of
these papers are provided within the text at the end of this section.
Table 2-2. Key ASTM Standards Covering CIPP Installations
ASTM F 12 16
ASTM F 1743
ASTMF2019
ASTMF2599
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 Thermo setting Resin Pipe
(CIPP)
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
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, as well as 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.
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 quality control (QC) procedures such as locally weak or
porous areas of the liner.
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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 (also known as "wet out")
in a factory setting. Typically, a vacuum impregnation process is 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 separate Insituform 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.
Small diameter liners (e.g., for sewer laterals) and very large liners can be wet out at the site. For small
liners, this can 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 2-2).
Figure 2-2. 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 ultraviolet (UV) light causing the liner resin to become a cross-linked and solid liner material.
The curing procedures (e.g., 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. Research into the magnitude
of this effect can be found, for example, in Hall and Matthews (2004), Bakeer et al. (2005), and Bakeer
and Sever(2008).
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Figure 2-3 highlights the main differences in CIPP technologies available today based on tube
construction, method of installation, curing method, and type of resin. The original CIPP product was a
needled felt tube, impregnated with polyester resin that was inverted into a sewer through a manhole and
cured using hot water. This product is still used for gravity sewers.
CIPP
LTube
Construction
Composite
^ Fiber-reinforced
Resin-felt
Composite
Resin-Glass
Fiber Composite
1 Reinforced
Hvhrirf
Installation
Method
1
-
Jcure Resin
Method Type
Inversion
Pull-in
and Inflate
Ambient
HT
Water
Steam
1 Ultraviolet
-
4
-
\
Polyester
Vinyl
Eater
Epoxy
Figure 2-3. Summary of Common CIPP Technologies
The following sections describe the major generic technology variants for CIPP rehabilitation in terms of
the tube construction, choice of resin, cure method, and insertion method. Appendix A in the companion
EPA report (Sterling et al., 2010) contains datasheets provided by some of the most established vendors
for specific products representing these variants. Due to the wide range of manufacturers and contractors
offering CIPP rehabilitation, it was not possible to represent all products with individual datasheets in that
report.
2.2.3 Installation Method: Inversion or Pull-In. From the first installation of CIPP in 1971 until
1973, the installation method involved a pull-in-and-inflate procedure. In this method, the uncured liner
is pulled into position directly as shown in Figure 2-2. An outer layer confines the resin during
impregnation and pull-in. This layer remains between the cured CIPP liner and the host pipe, which
reduces the potential for interlock between the resin and the host pipe, but fully confines the resin, thus
avoiding the potential for blocked laterals and washout of the resin by high groundwater inflows. Either
an internal hose (called a calibration hose) inflates the liner within the host pipe and holds it under
pressure until the liner is cured, or the ends are tied or plugged and the liner is simply inflated while
curing.
In 1973, coated felt was introduced allowing the liner inversion process to be used (see Figure 2-2). In
this process, the impregnated but uncured liner is forced by water or air pressure to turn itself inside out
along the host pipe section to be lined. Since there is a sealing layer outside the felt tube, this liner can be
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impregnated with resin and still handled easily prior to installation. When the liner is inverted, this
sealing layer becomes the inner surface of the CIPP liner. The uncured resin can then flow into cracks
and openings in the host pipe to lock the liner in place. For structural purposes, a small amount of excess
resin ensures that sufficient resin is available to give the required liner thickness. However, too much
resin can cause problems such as blocking sewer laterals. A second advantage of the inversion approach
is that the liner is not dragged, relative to the host pipe, as it is installed; rather, the liner unfurls itself
along the pipe, sealing off infiltration and displacing standing water in the pipe as it moves along the pipe
as well as reducing the potential for physical damage to the liner. In early CIPP installations, the coating
layer was a sacrificial polyurethane layer expected to hydrolyze over time. Today, more permanent
coating layers are used - either a different polyurethane (PU) layer or a polyethylene (PE) layer. A future
area of research could be the performance of the PU/PE layers during installation and over the long term.
Variations of each method (inversion or pull-in-and-inflate) are used, depending on the circumstances.
For example, a PE tube, or a separate layer of coated felt, can first be inverted into the host pipe as a
"preliner" and then the actual liner inverted inside the first tube. This will eliminate concern about resin
washout if high groundwater inflows are present.
2.2.4 Tube Construction. Initially the CIPP tube (also called "bag") construction was made of a
needled polyester felt and served only as a carrier for the resin. In this construction, the resin is the
dominant contributor to the mechanical properties of the system. Other forms of tube construction
entered the marketplace in the U.S. during the 1990s. These may involve the inclusion of reinforcing
materials such as fiberglass, aramid fibers or carbon fibers in some configuration. The reinforcement may
be positioned at selected points within the thickness of the tube wall or the wall may consist primarily of
braided reinforcing layer(s) (Rahaim, 2009).
Reinforced tube construction has been in use in Europe for longer than in the U.S. and allows the
designer/contractor to design a thinner CIPP liner and one with a wider range of application. The
reinforcing layers within the resin become a significant contributor to the mechanical properties of the
finished liner. This leads to a more complex mechanical behavior of the liner and the reduced thicknesses
are more susceptible to the effects of host pipe and liner imperfections on the structural analysis. Studies
of new composite tube materials can be found (e.g., Akinci et al. [2010]).
Liner thicknesses may vary from around 0.12 in. (3 mm) in small-diameter shallow pipes to over 2 in. (50
mm) in large-diameter deep pipes. In the construction planning for the CIPP project, consideration needs
to be given to the forces that will be exerted on the tube during the installation process. For the inversion
process, sufficient pressures must be exerted to allow the liner to "invert". For the pull-in process, the
liner tube construction must provide sufficient tensile strength for the pull-in and resistance to damage or
tearing during the insertion. Liners to be installed on steep-gradient pipes pose particular challenges for
water inversion and curing because sufficient pressure must be available at the upper end of the pipe to
allow the inversion to occur, but the pressure at the lower end of the pipe must not be so high as to cause
liner tearing or excessive thinning. In designing the tube thickness, consideration needs to be given to the
maximum pressure exerted on the liner as it cures so that the final thickness of the liner meets the project
specifications. The contractor or supplier calculates these parameters based on the site information and
planned installation procedures.
2.2.5 Choice of Resins for CIPP. The following discussion of resin chemistries is summarized
from a paper on "Resin Choices for Cured-in-Place Pipe Applications" by Rose and Jin (2006).
According to Rose and Jin (2006), there are three main chemistries of thermoset resins that are well-
suited for use in CIPP applications. These are polyester, vinyl ester, and epoxy resins.
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The most commonly used resins are isophthalic polyester resins (used in perhaps more than 80% percent
of the CIPP market worldwide [Downey, 2011]). These are usually medium reactivity, rigid, and
corrosion-grade resins with a high viscosity when compared to standard laminating resins. They typically
contain fumed silica to help prevent resin drainage from the upper portion of the pipe liner during the
curing process. They are a good choice for most municipal sewer applications due to their lower cost in
comparison with vinyl ester and epoxy resins and an adequate level of water and chemical resistance.
Iso-polyesters impregnate liner materials well and can be cured even when ambient temperatures drop to
near or below freezing.
Fillers can be used in the resin (especially in larger diameter liners) to increase the flexural modulus of the
cured liner which, in turn, reduces the required thickness of the liner - saving material and cost. Fillers
also improve the heat transfer characteristics of the resin. The filler is usually alumina trihydrate (ATH)
or more recently talc.
Three other types of polyester resins have been used in sewer line rehabilitation. One type involves
polyester resins based on terephthalic acid. These resins have greater tensile toughness and a higher heat
distortion temperature than standard polyester resins but require higher processing temperatures,
pressures, and cycle times which increase costs. Another polyester resin is based on orthophthalic
anhydride and has been used in Europe. This type of resin is not currently used in CIPP applications in
North America and is viewed as a low quality resin choice and it is not capable of meeting the chemical
resistance requirements of ASTM F1216. Polyester resins based on bisphenol fumarate offer outstanding
resistance to caustic and oxidizing environments making them an excellent choice for sewer lines
requiring a high degree of chemical and temperature resistance. However, this type of resin is highly
reactive and can suffer from blisters in the liner coatings or discoloration in the liner making their
appearance less desirable. Some manufacturers offer resin blends of isophthalic and terephthalic, but
blends with orthophthalic resin may not be capable of meeting the chemical resistance requirements of
ASTMF1216
Vinyl ester resins are typically used in applications where improved chemical and temperature resistance
is necessary. They also provide better initial and retained structural properties than the standard polyester
CIPP resins. The resins are styrenated, bisphenol A - extended epoxy polymers containing reactive
methacrylate end groups. Vinyl ester resins are substantially more expensive than the standard polyester
resins. A less-used variant of the vinyl ester resin is a urethane-modified vinyl ester resin.
Epoxy resins are also used in CIPP applications. The higher cost of epoxy resins means that they are
primarily used in pressure pipe and potable water applications. They can also be used where it is
important to avoid the release of styrene odors - such as in the relining of sewer laterals. The odor
release of epoxy resins depends on the use of volatile components in the formulation - and high solids
content epoxies release the least odor.
Rahaim (2009) also discusses recent developments in thermosetting resins to provide resins that are more
capable of handling corrosive environments, and higher pressure applications. Some products continue to
be styrene based whereas others have no styrene and some even have no hazardous air pollutants (HAPs)
and no volatile organic compounds (VOCs). Some resins are considerably more expensive than their
contemporary counterparts, some more economical. Rahaim (2009) suggests that care also needs to be
exercised to make sure that replacements for styrene offer tangible benefits in terms of odor reduction and
potential contamination concerns.
2.2.6 Thermal Curing Process. Thermal curing of CIPP liners is the most widely used curing
method in North America. Thermal curing includes supply of heat via contact with hot water, steam, or
hot air or by allowing the liner to cure by exposure to ambient temperatures.
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Ambient curing is typically only used for small diameter pipes (e.g., laterals) and is sensitive to climatic
conditions. The slow rate of curing reduces productivity and increases the sewer's out-of-service time
making its use in sewer mainlines uneconomical. Hot water curing is the original curing method for CIPP
and can be used in the curing of liners for the full range of host pipe diameters. Steam curing provides a
more rapid cure than hot water, and thus increasing job site efficiency. It involves less process water, but
increases safety issues. It is only used in the small to medium diameter range because the evenness of
curing conditions is harder to control in large diameter pipes and over long installation lengths. The
steam has less "thermal mass" which makes the curing more susceptible to circulation problems whereby
either insufficient heat is provided to allow a complete cure of the resin or excess heat from the resin
exotherm is not removed causing a resin boil. Also, the formation of condensate pools in the liner invert
needs to be avoided as this can also lead to inadequate curing of this region of the liner. In both cases,
temperature measurements are taken as the liner cures to track the exothermic reaction and to ensure
complete cure of the resin. The installation procedures and QA/QC requirements will change according
to the curing method chosen.
Figure 2-4. UV Light
Curing Train
Smaller mainline CIPP liners are typically prepared to the appropriate
diameters and impregnated ("wet out") with resin in the factory. They are
then shipped in a refrigerated truck to the job site for insertion and curing.
Lateral liners (3- to 4-in. diameter) are frequently impregnated by hand onsite.
Large-diameter liners are also wet out onsite using special wetout facilities.
Care needs to be taken that a liner does not begin to cure before or during the
installation process.
2.2.7 Ultraviolet Light Cured Liners. UV light cured liners were
developed and used in Europe by Inpipe from 1986 (Downey, 2011). A
German company, Brandenburger GmbH, later became a widespread provider
of resin pre-impregnated, UV-light-cured laminates for sewer rehabilitation.
In 1997, Brandenburger began promoting its technology outside Germany.
Its U.S. licensee, Reline America, Inc., was established in 2007 to distribute
this UV-cured, glass-reinforced CIPP liner to licensed contractors. In this
product, a seamless, spirally wound, glass-fiber tube is impregnated with
polyester or vinylester resins. The seamless liner has both an inner and outer film; the outer film blocks
UV light. The inner film is removed after curing. The shelf life of the impregnated liner is approximately
6 months. The liner is available in diameters from 6 in. to 48 in. and can be used in circular, oval, and
egg-shaped pipes. Reline America reports that up to 60-in. liners will be available in the near future and
that individual installation lengths of up to 1,000 ft are possible. The liner tube is winched into the
existing pipe and inflated with air pressure (6 to 8 pounds per square inch [psi]) and then cured using a
UV light train (see Figure 2-4). For QA/QC purposes, in addition to CCTV inspection of the line before
and after curing, a record of the liner's inner air pressure during curing, the curing speed (ft/min), and
resin reaction temperatures (infrared sensors) are all monitored. Other vendors of UV-cured CIPP include
BKP Berolina, LightStream, and Saertex.
2.2.8 Emerging and Novel CIPP Technologies. One of the latest glass-reinforced CIPP liners to
enter the U.S. market is Berolina Liner® from BKP Berolina Polyester GmbH in Germany. CIPP
Corporation is the U.S. licensee. The liner was first used in Europe in 1997 and outside Europe beginning
in 2001. At the time of this report, there have not been any U.S. installations, but the liner has been used
in Canada (Hamilton, Ontario). The liner is composed of glass fiber and/or polyester webs impregnated
with polyester or vinylester resin. Uniquely, the layers are overlapped and staggered giving the tube
variable stretching capability. After placement of a protective film sleeve covering the lower half of the
host pipe, the liner is installed by pulling it in place, which can be accommodated by the axial strength of
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the glass fiber. The tube, which is expanded by inflating it with compressed air, can be inspected with a
CCTV camera before polymerization. Once it is confirmed that the liner is correctly placed, it is then
UV-cured (Reeling, 2009). The liner has a protective inner film and a UV-resistant outer film. The inner
film is removed after installation. The outer film prevents resin from migrating into laterals, as well as
from entering cracks in the host pipe. The outer film also prevents significant styrene emissions. A
rehabilitated length of up to 1,200 ft is reportedly possible. The Berolina Liner is available in diameters
of 6 to 40 in., with thicknesses ranging from 0.08 to 0.47 in.
Insituform I-Plus Composite™ is a thermal curing liner developed to reduce the need for high liner
thicknesses in large-diameter pipes and/or with high external groundwater pressures. The liner cross
section includes fiber-reinforcing layers at the liner's top and bottom surfaces. These give the liner a very
high strength and stiffness, allowing the liner's overall thickness to be reduced (Hahn, 2007).
2.3 North American Experience with CIPP
2.3.1 Experiences and Case Histories. As indicated above, CIPP liners have been in use in the
U.S. since 1976. Judging by their continued and expanding level of use, system owners generally have
been happy with the installation and continued performance of CIPP liners. However, there is rather
sporadic documentation in the literature of the level of problems experienced, the nature of specific
defects that may occur and what steps need to be taken when defects do occur. Some papers that provide
information on significant or extensive experiences with CIPP include Driver and Olson (1983), Hannan
(1990), Barsoom (1993), Hudson (1993), Larsen et al. (1997), Hutchinson (1998), Llagas and Cook
(2004), Kahn (2005), Kahn and Dobson (2007), Lindsey (2007), Schwarz (2007), Kurz et al., (2009), and
Lehmannetal. (2009).
In addition, many project case history descriptions can be found in conference proceedings of the North
American Society for Trenchless Technology (NASTT), International Society for Trenchless Technology
(ISTT), the Pipeline Division of the American Society of Civil Engineers, the Water Environment
Federation Technical Exhibition and Conference (WEFTEC) and other specialty conferences of the Water
Environment Federation, and the Underground Construction Technology (UCT) conference. A few
examples include Bonanotte and Kampbell (2004), Hansen (2005), Nelson et al. (2005), Pennington et al.
(2005), Martin (2007), Dawson (2008), and Brand et al. (2009).
2.3.2 Testing and QA/QC. Since CIPP was introduced in the U.S. and has grown in popularity,
various standards and test procedures have been developed to govern its use. In addition to the ASTM
standards governing its use and testing (see Sterling et al., 2010, Appendix B), design guidelines and best
practices can be found in sources such as Bennett et al. (1995) and the NASTT best practices short course
for CIPP (www.nastt.org/training curedlnPlace.php).
Municipalities, consultants, and industry members have reported on their experiences in testing and
QA/QC practices. Such references include Pang et al. (1995), Yoshimura et al. (2006), and Herzog et al.
(2007). Recent work on QA/QC practices and testing procedures can be found in Lee and Ferry (2007),
Araujo et al. (2009), Gumbel (2009), Knight and Sarrami (2009), and Kampbell et al. (2011).
The need to develop adequate design procedures and to test products for CIPP application led to an
intensive series of research efforts focusing on pipe rehabilitation using thin, polymer liners within host
pipes subjected to external loads. This research includes the following papers: Guice et al. (1993), Guice
et al. (1994), Straughan et al. (1995), Li and Guice (1995), Falter (1996, 2004, 2008), Omara et al. (1997),
El-Sawy and Moore (1998), Straughan et al. (1998), Hall and Zhu (2000), Zhao et al. (2001), Zhu and
Hall (2001), Kapasi and Hall (2002), Thepot (2003), Zhao et al. (2005), and Zhao and Whittle (2008).
This is by no means a complete list, but should provide a good starting point for in-depth study. The list
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does not include work on the behavior of internally pressurized liners for water main or force main
renovation.
Research on the appropriate external loadings to be designed for CIPP installations has also been carried
out, including Spasojevic et al. (2004), Spasojevic et al. (2007), Law and Moore (2007), and Moore
(2008).
If the types or ratio of resins are an area of concern, QA/QC using nuclear magnetic resonance testing can
be carried out to make this determination. Research on the properties of resins used for CIPP includes
Kleweno (1994), Hayden (2004), and Bruzzone et al. (2008).
2.3.3 Environmental Issues. The principal issue rose about the environmental impacts of CIPP
materials and their installation has been the release of styrene into the process water (or other water
present in the host pipe) and into the air. This has been a significant issue in Europe encouraging changes
in the way that CIPP is manufactured and supplied and the switch to UV-cured liners for smaller diameter
CIPP rehabilitation. UV-cured liners (such as the German Brandenburger liner) use gas-tight membranes
to minimize the release of styrenes during storage and installation and the UV-cure process does not
require water or steam into which styrenes could leach before curing. Papers and reports discussing this
issue in the U.S. include Lee (2008), Donaldson (2009), and Kampbell (2009). In most areas of the U.S.,
styrene-based CIPP resins with thermal curing are still in use, but closer attention to reducing gaseous
styrene emissions and capturing water/condensate containing styrene is generally being practiced. The
smaller quantities of liquid water present during steam curing means that water contamination is more
easily handled in steam cures than in water cures (Kampbell, 2009).
There is very little information concerning the environmentally-caused degradation of CIPP. Two
references identified on this topic are Sever et al. (2005) and Potvin et al. (2008). In the evaluations of
the oldest CIPP liners from the current study (see Sections 4 and 5), it was noted that the coating layer on
the interior of the polyester resin was degraded or missing in the areas exposed to flow. This coating
layer was used to isolate the polyester resin from the environment during impregnation, installation, and
curing. Once cured, the layer had essentially served its purpose. Long-term exposure to water caused the
polyurethane film used in early installations to breakdown due to hydrolysis, a process of slow but
temperature-dependent dissolution. In newer liners, both improved formulations of polyether
polyurethane (which has good resistance to hydrolysis) and PE are used as a coating material. The
longevity of both coating materials is expected to be greatly improved over the original form of
polyurethane coating.
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3.0: DEVELOPMENT OF CIPP EVALUATION METHODOLOGY
3.1
Review of Potential Alternatives
A variety of approaches to evaluate the state of deterioration of previously installed liners were
considered in the initial stages of the project. Table 3-1 indicates the main alternatives considered and the
advantages and disadvantages of each approach. Through a detailed literature search and the specific
international scan effort described in Section 8, the research team was only able to find scattered efforts to
thoroughly evaluate the long-term performance of rehabilitated sewer sections. Most typically, the
rehabilitated sections were only evaluated using CCTV immediately following the installation and then
perhaps periodically using CCTV depending on the overall inspection strategy of the agency. In some
cases, this would mean a regular CCTV inspection at intervals of a number of years, while in other cases
it may mean no follow up since the rehabilitated section would be moved to the lowest priority for
inspection.
Table 3-1. Potential Evaluation Strategies for Liner Deterioration
Evaluation approach
Advantages
Disadvantages
Targeted or periodic CCTV
inspection
Relatively low cost
Familiar to agencies
Can uncover other operating
problems such as potential
blockages
Can provide broad coverage
of relined sections within an
agency leading to
statistically meaningful
results
Can only identify
deterioration or defects that
are easily identified by
CCTV inspection
No material properties
obtained
Liner distortion difficult to
identify
Not possible to evaluate
intermediate stages of
deterioration
Advanced scanning and non-
destructive testing (NOT)
methods
More detail on such aspects
as liner distortion,
development of external
voids, etc.
More expensive than CCTV
Data that can be gathered
still would not presently
allow evaluation of
intermediate stages of
deterioration
Recovery of destructive samples
from select locations
Physical samples of the liner
are available for a variety of
tests
Variation of material
properties from as-installed
requirements can be
determined
Comparison with NOT
methods possible to build
future NOT evaluation
procedures
Expense of retrieving
physical samples limits the
number of samples that can
be recovered and hence the
statistical validity of results
in terms of system-wide
performance
Expense can limit the wish
of agencies to participate in
a national evaluation
program
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3.2 Goals for a Specific Retrospective Evaluation Using the Draft Protocols
The goals of the retrospective evaluation of a rehabilitation technology in a specific municipality are:
• To gather quantitative data on the current condition of a specific rehabilitation system using a
draft protocol for the inspection, defect classification, sample collection, testing, analysis, and
storage of such data.
• To evaluate the protocol as to its appropriateness for use under field conditions in a
municipality. Will it produce the desired data? Is the terminology used universally accepted
and understood by the municipal engineering community? Is it excessively burdensome on
the utility? Can the data collected be used effectively to guide asset management decisions?
• To compile the evaluation results into a common database so that cities can understand how
the systems that they are investing in today have performed over their commercial life to
date.
3.3 Preliminary Outline of Anticipated Protocol for CIPP Evaluation
The project team initiated discussions early on with municipalities interested in participating in the project
in order to aid in the development of the data collection protocols. A preliminary outline was prepared
that was intended to give the municipality an idea of the anticipated scope of the evaluation and a chance
to make suggestions to improve the protocol or increase its feasibility for the municipality before it was
finalized. The utility owners were expected to collaborate on the project and provide in-kind
contributions associated with the following:
• Providing historic and current background data, maps, and drawings to the Battelle team;
• On-site support for field testing and sample collection for destructive testing, such as traffic
control, utility locating and designation, excavation and surface restoration at access points,
and CCTV inspection; and
• On-site support for non-destructive testing (NDT), such as pipeline cleaning, traffic control,
utility locating and designation, excavation of access points, and other relevant site work.
More detail on the anticipated protocols and municipal interactions are provided below.
3.3.1 Identification of Municipal Partners
• The municipality would have at least 10 years of experience with CIPP installations -
preferably more. Experience with more than one contractor and/or technology supplier
would be a plus.
• The evaluation protocol was intended to be initially applied to mainline gravity sewers in the
8 in. to 24 in. range, although the diameter range was open to adjustment if special
opportunities were presented themselves.
• The municipality would be willing to help to identify appropriate segments for quantitative
evaluation.
• The municipality would be willing and able to provide a reasonable level of design and
construction data for the rehabilitated segments - i.e., quantitative data that would establish
the as-installed condition and engineering parameters for the liner.
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• The municipality would be willing to provide the equipment and labor to retrieve field
samples of a lined pipe for evaluation or field support for NDT of other lined segments.
• Members of the EPA project team would be on site for the sample retrieval and liner
evaluation in the field. The project team would also be responsible for all liner testing and
analysis carried out off site and would provide a report of the data collected and its
interpretation to the municipality.
• The municipality will have the option to not have their name associated with specific data or
analyses conducted.
3.3.2 Identification of Segments for Evaluation
• Ideal segments for evaluation would be where a dig up and replacement of a rehabilitated
segment is planned for reasons other than problems in the rehabilitated line or where a dig up
and removal of a pipe segment can be scheduled prior to street repaying, etc.
• If a dig up and replacement of a segment was not possible, then an area where a physical
sample could be removed from within the line would be considered. This could be adjacent
to a manhole or in a pipe large enough for the removal of a sample with adequate dimensions
for physical property testing (e.g., 2 in. by 6 in. coupons).
• NDT measurements would also be applied to segments where physical samples are removed
to determine if the same conclusions concerning liner properties could be derived from the
non-destructive measurements (either within the line or where the liner was accessible at a
manhole).
• Mainline segments where lateral rehabilitation was planned could also provide an opportunity
to remove samples adjacent to the lateral and then covering the removed coupon areas with a
T-Liner type of lateral rehabilitation that included an integral mainline collar.
• In order to test the application of the protocols and monitor time and cost to perform the
evaluations, it was anticipated that two different line segments would be selected in each
cooperating utility.
3.3.3 Availability of Historical Data. The following historical data would preferably be available
for use in the retrospective evaluation (it was realized that not all the elements of the list below would be
available):
• Location and length of lined segment, slope of pipe
• Type and diameter of host pipe and condition of the host pipe prior to rehabilitation (partially
or fully deteriorated, any recorded ovality, etc.)
• Repair history prior to rehabilitation
• Estimated flow data, frequency of surcharging, and any substantial changes since
rehabilitation
• Soil conditions and/or backfill conditions at the time of pipe construction
• Any evidence of soil voids outside the pipe prior to rehabilitation
• Any special chemical aspects to the wastewater carried in the rehabilitated pipe
• CCTV data pre- and post-rehabilitation
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• Date of rehabilitation
• Rehabilitation technology used (including specific variations such as inverted vs. pull in, use
of a pre-liner, type of cure used [e.g., hot water, steam, ambient])
• Construction records for the selected rehabilitation location
• Inspection reports for the selected rehabilitation location
• Material test data for the materials used in the rehabilitation: manufacturer-provided data and
preferably actual test data on the installed materials
• Any samples retained in storage that were retrieved during the construction process
• Municipal employees familiar with the specific rehabilitation installation.
3.3.4 Retrieval of Field Samples (Dig up and Replace Sample). The type and dimensions of
field samples retrieved would be determined in conjunction with the preferred segments for evaluation.
In the case of an opportunity to dig up and replace a sample, the following protocol was envisaged:
• A pipe sample length of at least 18 in. (preferably at least 36 to 48 in. would be retrieved).
The lined pipe segment would be boxed and shipped to Louisiana Tech University for liner
evaluation and testing.
• The type and condition of the host pipe and the surrounding backfill would be noted during
excavation together with confirmation of pipe depth, pavement type and thickness, and other
factors relevant to pipe loading conditions.
• The orientation of the pipe sample would be marked on the pipe at the time of retrieval.
• Laboratory test samples would be retrieved from these full pipe samples in the laboratory.
• Various in-situ non-destructive evaluation methods would also be applied adjacent to the
removed section and at the manholes at either end of the segment.
3.3.5 In-Situ Evaluation. In the case that dig up and replacement of a segment would not be
possible, the evaluation would be carried out using non-destructive or minimally destructive evaluation
(e.g. coupon sampling) methods. The exact methods to be used were to be determined during the
continuing protocol development, but would ideally include most or all of the following:
• Cleaning of the line and temporary stoppage or bypassing of flow in the segment
• CCTV inspection of the line to carefully document any defects, discolorations, etc.
• Laser profiling for accurate internal dimensional checks of the finished liner (e.g., assessing
ovality).
• Ultrasonic thickness measurements (by hand close to manholes)
• Feeler gauge measurement of the annular gap adjacent to the manhole
• Surface hardness measurements (by hand close to manholes) - if the diameter of the host pipe
was sufficient to apply such measurements
• Physical sample retrieval (if feasible) for laboratory testing of constituent, material, and
structural properties of the liner, e.g., Barcol or Shore hardness, and laboratory glass
transition (Tg) testing to measure the degree of cure, tensile strength, and short-term modulus
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• Measurements and/or physical samples would be located in both the upper and lower portions
of the pipe. Locations would preferably be chosen to correspond with the locations of
samples taken at the time of installation.
• At least three samples or three of each type of measurement would be taken for the accessible
section of the liner. More measurements to define any differences around the perimeter of
the liner cross-section would be made where this was feasible.
In addition to the methods identified above which are in current practice, the project team would evaluate
other potential non-destructive or minimally-destructive methods to collect quantitative data on the liner
condition. These methods would not necessarily be available during initial trials of the protocol.
For the evaluations carried out in Denver and Columbus, described in the following two sections, physical
samples large enough for laboratory testing of properties were able to be retrieved and, hence only,
selected non-destructive inspections and/or measurements were made in the field to complement the
laboratory evaluations.
3.3.6 Evaluation of Results. The intent of this project is to explore the most appropriate protocols
for broad use in retrospective evaluations of CIPP liners in gravity sewer systems and to provide a
roadmap for how a consistent database of quantitative performance can be assembled by municipalities
and utility owners. The results from the initial application and testing of the protocol were not expected
to provide any definite results concerning the broad longevity of the liner system since there are not
enough sample locations to provide a statistical basis for conclusions about the rehabilitation
performance. However, the testing was expected to provide feedback about whether the test results
conform to the expectations of the municipality or show a significant deviation. In this regard, liners with
little deterioration in material or structural performance provide some reassurance about longevity
expectations, whereas liners that show greater than expected deterioration could raise a flag that this issue
should be evaluated more carefully.
Specific data sought from the retrospective evaluation trials include:
• Typical/dominant defects seen in the rehabilitation technology;
• Typical locations for such defects (i.e., near manhole, at crown of pipe, etc.); and
• Quantitative properties to assist in the evaluation of the current condition and expected
remaining life of the rehabilitation (e.g., thickness, flexural strength, stiffness modulus, and
creep properties).
The results collected from each individual utility eventually can be aggregated with those from other
utilities providing a broader statistical background for the performance of a particular rehabilitation
method.
3.4 Test Plans and Quality Assurance
Prior to conducting each of the Denver and Columbus retrospective evaluation programs, a Quality
Assurance Protocol Plan (QAPP) was developed to ensure the quality and validity of the field and
laboratory test data that would be used in further analysis. Each QAPP was approved by the Quality
Assurance Officer for the U.S. EPA National Risk Management Research Laboratory (NRMRL).
19
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Tables 3-2 and 3-3 provide a combined summary of the field and laboratory measurements for both sites
at each of the Denver and the Columbus evaluations. A few variations in the proposed plan were
necessary due to project and site circumstances and these changes are noted in the tables.
The critical measurements for this research were identified to be the tensile stress, flexural stress, and
modulus of elasticity of the retrieved samples. These laboratory measurements were conducted on all of
the samples retrieved from the Denver and Columbus evaluations described in the following two sections.
The results of the laboratory testing were compared with the material specifications for the original
relining work or directly with as-installed test results where available. The tensile strength was measured
with a minimum of three samples for each pipe segment. The flexural stress and modulus of elasticity
were measured with a minimum of five samples for each pipe segment. The standard operating procedure
(SOP) outlined in each of the relevant ASTM standards listed in Table 3-3 was followed.
Table 3-2. Field Measurement Plans
Field
Measurements
Soil conditions
+ bedding
Liner + host
pipe specimen
Liner only
specimen
Visual liner
inspection
Liner thickness
(Prior to
Sample
Retrieval)
Liner thickness
(After Sample
Retrieval)
Annular gap
No. of Measurements
Denver: 6 per site
Columbus: 6 per site
1 each
3 total
Continuous
Denver: mobile
equipment not available;
Columbus: 36 in. pipe 8
measurement; 8 in. pipe 5
x 2 = 10 measurements.
Panel samples: 4
8 in. pipe samples: 8x2
x2 = 32
Denver: 8 in. only 8 x 2 x
2 = 32 meas.
Columbus:
36 in. pipe: 4x2 = 8
measurements
8 in. pipe: 8 x 2 = 16
measurements
Sample
Grab samples
Denver 8 in.
clay pipe (6 ft
length);
Columbus 8
in. clay pipe
(6 ft length)
Denver 2
pieces each 2
ft x 2 ft;
Columbus 1
piece 2 ft x
4.3ft
N/A
N/A
N/A
N/A
Test Standard/
Instrument
See Table 3-3
N/A
N/A
N/A
ASTM E797-05
Ultrasonic
Thickness.
Measurement
(Olympus
Model 37DLP)
Caliper / ruler
Feeler gauge
Notes
Field visual inspection and
soil lab analysis
Shipped to TTC for further
testing
Shipped to TTC for further
testing
Digital photos as applicable
and possible.
36 in. pipe: 3 meas. within
panel ; 5 meas. in host pipe
(both spring lines, crown
and 45° on each side)
8 in. pipe: 5 meas. as above
on each cut face
Panels: 1 meas. on each
edge
8 in. pipes: Meas. at 45° for
each cut face at each end of
sample
8 in. pipes: meas. at 45°
both cut faces, both ends.
36 in. pipe sample: 2 meas.
on remaining liner at each
edge of removed panel.
N/A = Not Available
20
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Table 3-3. Laboratory Evaluation and Measurement Plans
Laboratory
Measurements
Density
Porosity
Tensile Strength and
Elongation at
Failure
Tensile Strength and
Elongation at
Failure
Flexural Strength
and Flexural
Modulus
Flexural Strength
and Flexural
Modulus
Short-term liner
bucking strength
Pipe Ovality
Duro meter (Shore)
Hardness
Barcol Hardness
Apparent Specific
Gravity
Glass Transition
Temperature
Visual Liner
Inspection
Soil Analysis
Raman
Spectroscopy
Samples
All
samples
All
samples
8 in. clay
Panel
samples
8 in. clay
Panel
samples
8 in. clay
8 in. clay
All
samples
All
samples
All
samples
All
samples
All
samples
Denver
and
Columbus
Excavated
samples
only (8
in.)
All
samples
No. of
Measurements
(each site)
Denver 7
Columbus 7
Denver 1
Columbus 1
Denver: 3
Columbus: 3
Denver: 3
Columbus: 3
Denver: 5
Columbus: 5
Denver: 5
Columbus: 5
Denver: 1
Columbus: 1
Denver and
Columbus: 1
each
5 each
5 each
3 each
2 each
Continuous
N/A
3 each
Sample
Size
N/A
N/A
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
4ft
sample
length
1ft
N/A
N/A
2 in. x 2
in.
3 in. x
0.5 in.
N/A
500 g
2 in. x 2
in.
Test Standard/
Instrument
ASTM D792
Mercury vapor
intrusion test
ASTMD638
ASTMD638
ASTM D790
ASTM D790
ASTM F 12 16
Profile plotter
ASTMD2240
ASTMD2583
ASTMD792
ASTME1356
Differential Scanning
Calorimetry (DSC)
N/A
ASTM C136 sieve
analysis; ASTM
C128 density;
ASTMD2216
moisture content;
and Thermo Orion
meter for soil pH
Raman Systems R-
3,000 Spectrometer
with a 785 nm diode
laser excitation
source
Notes
N/A
N/A
N/A
N/A
N/A
N/A
Modified according
to sample condition
Measurements
continuous in
buckling test sample
N/A
Added for
comparison with
other listed results
N/A
N/A
Surface film, leakage,
corrosion, bacterial
growth, etc.
N/A
Comparison with
similar virgin resins
made when feasible
N/A = Not Available
21
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3.4.1 Additional Testing Concepts. As the protocols were further developed in discussion with
the City of Denver and the City of Columbus, some additional avenues for testing or evaluation were
proposed either by the City or the research team. These are listed in Table 3-4 together with comments on
the potential value of the testing, expected difficulties in testing or interpretation, and the use of the
testing in the current pilot project. The main area of interest was to try to identify potentially useful new
approaches that could provide an indication of any liner deterioration - either NDT methods that could be
deployed within a pipeline or destructive methods that only required a small sample of liner material.
Such tests could then be correlated with the standard tests in this study to see if a relationship appeared to
resist. If so, then the promising tests could be evaluated further in future projects to fully establish the
validity of the approach.
Table 3-4. Additional Testing/Evaluation Concepts Considered
Test
Thermo -
Gravimetric
Analysis
(TGA)
Fourier-
Transform
Infrared
(FTIR)
Spectroscopy
Compression
Strength
Testing
Fractography
Rebound
(Schmidt)
Hammer
Chemical-
Resistance
Description
Measures the
weight loss of
the sample as it
is heated to show
the temperatures
at which
degradation
takes place.
Identifies the
nature of
chemical bonds
and the
crystalline
phases that
formed in the
material.
Provides a
material strength
parameter.
Examines
fracture surfaces
under a
microscope.
Data on surface
properties and
shallow
delaminations.
Used principally
for concrete
materials.
Measures the
strength loss of
samples that
have been
exposed to
chemicals.
Potential Value
This provides information
about the organic
components and could
identify degradation of the
CIPP material. Again,
comparison of surface
material versus core
material and/or control
samples would be useful.
If the resin is known, or if
samples of the resin are
available, spectra from the
field samples can be
compared to the resin. If
controls are not available,
spectra can be examined
for signs of degradation
such as oxidation products.
Would provide values for
comparison with flexural
and tensile test values.
Gain insight into what type
of failures are occurring in
liner materials.
Might provide insight into
surface deterioration of
liner materials and/or
evidence of delamination
in thin liners.
Would determine if the
specimens were still in
compliance with the
chemical-resistance
requirements of Table X2.1
ofASTMF1216.
Difficulties
The challenge is
developing a
testing protocol
that accounts for
the VOCs
common to many
resins used in
CIPP
installations.
None.
Liner thickness
and curved shape
not suitable for
compression test.
Complement to
other testing to
failure.
Current
equipment too
large to use in
small dia. pipes.
Value of
measurements
unclear.
None.
Application for pilot study
Preliminary tests during this
study did not yield
interpretable data,
potentially due to too high
temperature gap
Not used. One challenge for
a retrospective evaluation is
obtaining good control
samples for virgin materials
that may no longer be on the
market. Raman
spectroscopy was used for
the purposes of this study.
Not used.
Not used.
Not followed up at this time.
Shore and Barcol surface
hardness measurements
made instead.
Not used.
22
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4.0: CITY OF DENVER RETROSPECTIVE STUDY
4.1 Introduction
The initial discussions were held with the City of Denver during August 2009 about the City's
willingness to participate in the retrospective evaluation pilot studies. It was known that the City had
been one of the early adopters of CIPP lining in the U.S. The draft protocol outlined in Section 3 was
provided to the City so that they could understand the nature of the program and the requested role of the
City. After the City indicated its interest in participation on August 19, 2009, a face-to-face meeting was
organized and held in Denver on September 22, 2009.
At the meeting, the City identified a series of sewer mainlines in a residential area that had been relined
using CIPP in 1984. An additional advantage to the identified lines was that they were in alley locations
(low traffic) and that the alley pavement surface had areas that had been identified for replacement. The
City wished to complete the dig up of the 8-in. pipe and liner before winter and, hence, the field work was
organized for October 27, 2009. A CCTV inspection was made of several of the sewer lines that had
been relined in 1984 and the evaluations of liner defects seen from those inspections are given in
Section 4.2.17. However, the CCTV inspection was not used in this instance to pick a particular location
for the sample retrieval.
A second option for sample retrieval was identified as a brick sewer of 48-in. diameter that had a CIPP
liner installed in 1987. This liner had already had a physical sample removed for follow up testing in
1995 and, hence, another point of comparison for any degradation would be available. The retrieval work
and re-patching of the liner in this instance was carried out by one of the local CIPP contractors in the
Denver area (Wildcat Construction Co., Ltd.). The sample retrieval for this location was carried out on
May 20, 2010.
4.2 Site 1: 25-year Old CIPP Liner in an 8-in. Clay Pipe
4.2.1 Host Pipe and Liner Information
Location: City of Denver, CO: Monroe Street and 1st Street
Host pipe: Circular, 8 in. diameter, vitrified clay pipe (VCP)
Burial depth: 5 ft (above crown)
Liner dimensions: 8 in. diameter; 6 mm thick
Resin: Reichhold 33-060; an isophthalic, polyester, unfilled resin
Primary catalyst: Perkadox 16
Secondary catalyst: Trigonox C
Felt: Unwoven fabric (similar to products used today)
Seal: Polyurethane, 0.015 in. thick (today CIPP liners use polyethylene coating)
Year liner installed: 1984
Liner vendor: Insituform
Resin supplier: Reichhold
Tube manufacturer: Insituform
23
-------
4.2.2
Timeline for Fieldwork.
Tuesday, October 27, 2009
7:00 AM Contractor's (Brannan) crew began staging equipment and preparing the site for
the excavation.
7:30 AM Precut portion of the concrete paving slab in the alley was removed.
7:50AM After removal of the concrete slab, a soil sample was taken at the sub-grade level,
immediately beneath the concrete slab (sample No. 1 of 6).
8:00AM Excavation was halted and sample No. 2 of 6 collected from the bottom of the
trench, 2 ft below sub grade.
8:20AM Excavation was halted and sample No. 3 of 6 collected from the bottom of the
trench, 4 ft below sub grade and approximately 10 in. above the crown of the
pipe.
8:25 AM One of the Brannan crew members hand dug with a shovel and sample No. 4 of 6
was collected just above the crown of the pipe.
8:30AM Hand digging continued and sample No. 5 of 6 was collected along the spring line
of the pipe.
8:40AM Sample No. 6 of 6 was collected with continued hand digging at the invert of the
pipe. Work was suspended while waiting for the Hydrovac truck to arrive.
10:50AM Hydrovac truck arrived and removed the soil around the host pipe to minimize
disruption.
11:40AM Removal of the soil immediately surrounding the pipe was completed by hand
digging and a plastic shrink wrap material was applied in multiple layers to
support the pipe joints.
12:OON A support cribbing, constructed of two 2 in. x 12 in. wood planks was joined
together to form a "V" shaped support for the specimen. This was placed under
the specimen and the voids between the pipe and the support structure were filled
for added support with foam packing material. The 6 ft specimen was then lashed
to the wooden support structure with bungee cords, and additional layers of the
shrink wrap material were applied. Two lifting slings were then fitted to the pipe
specimen and the excavator. Support tension approximating the weight of the
specimen was applied to minimize stress and movement during the cutting and
extraction of the specimen.
12:10PM A gasoline powered cut off saw with a diamond dust embedded blade was used to
cut the specimen, and the specimen was lifted from the trench by the excavator
and held suspended for annular gap measurements.
12:15PM Measurements of the annular gap between the host pipe and liner were taken with
a feeler gauge at both ends of the specimen and at both ends of the remaining pipe
before the repair was made. The annular gap measurements were taken from the
crown and at 45 degree intervals along the circumference of the pipes, moving
clockwise while facing the end of the pipe being measured.
12:40PM Measurements were completed and Brannan crew finished wrapping the
specimen (lifting straps enclosed in wrapping) and loaded the specimen into the
bed of a truck for transport to Crating Technologies (see Figure 4-1).
Monday, November 2, 2009
Specimen was received at TTC.
24
-------
Figure 4-1. Images of the Recovered Specimen
4.2.3 Visual Inspection of the Liner. Overall the liner appeared to be in good shape. The
polyurethane coating seemed to be eroded away at the invert of the pipe. Upon discussion with the
vendor (Insituform), it was established that the polyurethane laminate coating was intended to serve as a
sacrificial layer and act as a barrier for preventing resin from entering the interior of the tube. It was
expected that this coating would hydrolyze over time (a chemical reaction causing the breakdown of
certain polymers). The vendor was surprised to find out that most of the polyurethane layer remained
intact (modern CIPP liners typically utilize a PE or a more durable polyurethane coating, which is
considered to be a permanent layer). In locations where the polyurethane coating hydrolyzed, the fibers
into which the polyurethane coating dissolved were exposed and somewhat loose. However, the resin-
impregnated felt beneath it was solid and intact. The stitched seam holding together the CIPP tube was
found to be in good condition. Signs of wear were restricted to the bottom third of the tube. A deposit
made up of silt and what appeared to be residue of an organic matter was found at the invert of the CIPP
liner (Figure 4-2).
Figure 4-2. Images of the Inner Surface of the 25-year Old, 6-ft Long CIPP Liner Section
25
-------
4.2.4 Locations of Soil Samples. The trench was divided into six regions (Figure 4-3) for soil
sampling. Soil samples collected from each region were placed in airtight bags to avoid foreign
contamination and/or loss of moisture. The samples were numbered as shown in Table 4-1.
CD
Ground
Table 4-1. Designation of Collected Soil Samples for
Denver 8-in. Site
Soil Sample Location
Sub-grade
2 ft below sub-grade
4 ft below sub-grade
Just above crown
Bedding along the spring line
Bedding under the invert
Sample ID
1
2
3
4
5
6
Figure 4-3. Location of
Soil Sample Collection
Place (Denver 8-in. Site)
4.2.5 Analysis of Soil Samples. Standard test methods ASTM C136 and ASTM C128 were
followed to classify the soil and determine its particle size distribution. In addition to those tests, the pH
of the soil samples was measured using a pH meter.
4.2.5.1 Particle Size Distribution. ASTM C136, a standard testing method used for performing sieve
analysis on geological material, was followed for the particle size distribution analysis. Based on visual
inspection, soil samples were categorized as fine aggregates. For this analysis, 500 g of soil material was
taken from each of the six soil samples and placed on a No. 4 sieve. For all samples, more than 90% of
the particles passed through a No. 4 (4.76 mm) sieve, suggesting that the analysis procedure for fine
aggregates should be followed. The resulting gradation curves are shown in Figure 4-4.
Based on grain size distribution, both the backfill and bedding soils can be considered to be sandy soils.
The steep slopes of the resulting gradation curves for the samples taken from the spring line and invert
elevations suggest that the bedding material consists of uniform (poorly-graded) soil. For the other
locations, the gradation of soil was determined to be a fair-graded material. Review of bore logs collected
as part of utility construction projects performed in nearby areas revealed that the native soil in the top 5
ft consist of sandy-silt underlying by gravelly sand (between 5 ft and 12 ft).
4.2.5.2 Soil Specific Gravity and Absorption. ASTM C128 standard method was used to calculate
the density, relative density, and absorption of fine aggregates. Soil material weighing 500 g was taken
from each of the six samples for the needed tests. The results are listed in Table 4-2.
4.2.5.3 Soil Moisture Content. ASTM D2216 is a test method used to determine the moisture
content in soils and rocks by mass. Samples weighing 1,000 g from each of the six locations were placed
in an oven for a period of 24 hr. After 24 hr, the soil samples were weighed and returned to the oven for
an additional 24 hr period. The process was repeated until the difference between two subsequent
measured weights was less than 1 g. At this point the soil was assumed to be moisture free. Moisture
content values for the six soil samples are listed in Table 4-3.
26
-------
-*-
-M-
100
90
80
70
f ..
5 50
S 40
V
a 30
20
10
0
0.0
-Subgrade -»-2' below subgrade — *— 4' below subgrade
•Just above crown — «— Bedding alongthe spring line • On the invert
Clay
• -•«
Silt
1 •*
301 0.001
•.•«.-
::( :•-
Sand
1 -*
,/
J
HMriH
/^
1
0.01 0.1
Diameterin(mm)
BMW
^
/
/
?
M.I.T
Class ' -.:•
*=
•1
*
s
\
1
i
n
10
Figure 4-4. Soil Grain Size Distribution (Denver 8-in. Site)
Table 4-2. Soil Specific Gravity and Absorption (Denver 8-in. Site)
Sample
ID
1
2
3
4
5
6
Soil
(g)
500
500
500
500
500
500
Bulk Specific
Gravity (OD)*
2.04
1.94
1.96
1.95
1.94
2.24
Bulk Specific
Gravity (SSD)**
2.25
2.14
2.17
2.09
2.07
2.36
Apparent
Specific
Gravity
2.59
2.41
2.48
2.27
2.22
2.56
Absorption
(%)
10.40
9.99
10.77
7.25
6.32
5.62
*OD: Oven dry.
** SSD: Saturated surface dry.
Table 4-3. Soil Moisture Content (Denver 8-in. Site)
Sample ID
1
2
3
4
5
6
% Moisture Content
9.59
8.99
9.51
6.85
6.37
5.59
27
-------
4.2.6 Measurement of Acidity, Alkalinity, and pH. The pH of the soil embedment and the solid
sediments collected from the pipe invert were measured using a Thermo Orion pH meter (Figure 4-5).
The soil samples were placed in a pan (which was rinsed using distilled water) and distilled water was
added to the samples. The soil sample was then stirred, and the pH probe was inserted into the soil-water
mixture. The process was repeated for the sediments collected from the bottom of the liner on the inside
of the pipe. The pH values of the bedding soil, backfill soil, and the sediments are listed in Table 4-4.
Table 4-4. Soil pH at Designated Locations and
Sewage pH (Denver 8-in. Site)
Designation
1
2
3
4
5
6
Soil, pH
7.46
7.23
6.53
4.20
3.84
4.03
Sample
1
2
3
-
-
-
Sediment, pH
6.59
6.35
6.14
-
-
-
Figure 4-5. Measurement of pH Using a
pH Meter
The soil samples collected from around the pipe (bedding material) were found to be rather acidic in
comparison to the upper backfill soil. The soil pH ranged from 3.8 to 7.5 with a corrosive soil defined as
having a pH less than 5.5. Therefore, the soil above the crown and in the bedding material adjacent to the
pipe (samples 4, 5, and 6) would be considered corrosive. The sediments inside the pipe were found to be
only slightly acidic with an average pH of 6.4, as expected from a residential wastewater stream. Thus, it
is not likely that the liner was subjected to a rigorous chemical attack during its service life.
4.2.7 Annular Gap. Measurements of the annular gap between the liner and the host pipe were
taken at 45 degree intervals around the circumference of the liner. The removal of the host pipe plus liner
allowed measurements to be taken on both sides of each cut face, resulting in a total of four measurement
locations for each of the 8 o'clock positions around the liner circumference. The measurement results are
provided in Table 4-5.
The maximum annular gap measurement was 3.3 mm, but the average annular gap value was only
approximately 0.9 mm compared to the nominal liner thickness of 6 mm. Annular gap is of interest in
liner performance for several reasons. Structurally, a tight liner with small annular gap will have a better
resistance to external buckling for the same thickness of liner. A tight liner is also more likely to be
locked into place within the host pipe by minor irregularities and joints in the host pipe, limiting the
potential longitudinal movement of the liner due to temperature changes or other forces that may act on
the liner. From an infiltration perspective, a tight liner limits the flow of water in the annular space that
may bypass the liner by entering the lined pipe at lateral reconnections or at the manholes (if these are not
sealed). The measurements taken on this liner indicate that it remains a tightly fitting liner.
28
-------
Table 4-5. Denver 8-in. Liner Annular Gap Measurements
Location
Crown
45 ° crown- Right SL
Right spring line
Right haunch
Invert
Left haunch
Left spring line
45° crown- Left SL
North End of
Specimens
(mm)
3.31
0.10
2.55
0.58
1.76
0.68
0.89
0.10
South End of
Specimens
(mm)
0.66
0.44
0.43
0.43
0.59
0.43
0.59
0.57
North End of
Remaining Pipe
(mm)
1.04
0.64
0.46
0.64
0.71
0.20
0.20
0.64
South End of
Remaining Pipe
(mm)
0.13
0.20
0.58
0.58
1.24
0.20
0.20
0.20
4.2.8 Liner Thickness. A total of 72 readings were taken to measure the thickness at different
locations around the pipe circumference. These readings were taken using a caliper with a resolution of
+0.0001 in. The average thickness of the liner is shown in Figure 4-6. The thickness of the liner was
found to vary slightly around the circumference of the liner with the maximum thickness at the crown
(5.98 mm ± 0.07 mm) and slightly lower values at the spring line (5.93 mm ±0.11 mm) and the invert
(5.91 mm ± 0.09 mm). This was attributed mostly to the erosion of the polyurethane coating layer
(approximately 0.38 mm thick), originally placed on the internal surface of the liner, at the invert zone.
The average measured thicknesses after 25 years in service were all slightly lower than the designed
thickness of the liner (6 mm) although some individual readings were higher. No ultrasonic field
measurements of liner thickness were possible in the field and when attempted in the laboratory the
measurements were not successful. A discussion of this issue is provided in Section 6.
E
e
O)
c
7.0
6.8
6.6
6.4
6.2
6.0
5.8
5.6
5.4
5.2
5.0
Denver 8-in.
Designed thickness 6mm
Weighted average (SL) 5.93 mm ±0.11 mm StDev 0.324
Weighted average (Crown) 5.93 mm ±0.07 mm StDev 0.264
Weighted average (Invert) 5.91 mm ±0.09 mm StDev 0.302
Cl C2 C3 C4 C5 C6 C7 C8 C9
Measured Samples
SLl SL2 SL3 SL4 SL5 SL6
II 12 13 14 15 16 17 18 19
Figure 4-6. Average Thickness at Different Locations on the Liner
29
-------
4.2.9 Specific Gravity and Porosity. For this liner, the specific gravity and porosity of the liner
were measured using a mercury penetration test carried out by Micrometrics Analytical Services. The test
data indicated that the bulk density (at 0.54 pounds per square in. absolute [psia]) was 1.0731 g/mL, the
apparent skeletal density was 1.2762 g/mL and the porosity was 15.915%. The specific gravity was also
measured by TTC with a higher value reported (1.159 ± 0.93 compared to the 1.0731 value measured in
the mercury penetration test). The TTC value is closer to the specific gravity of 1.19 measured by
Insituform on a sample sent to them for parallel testing (see Table 4-9). The full Micrometrics test reports
for all the liners tested are included in Appendix C and the results are discussed further in Section 6.
4.2.10 Ovality. A profile plotter (Figure 4-7) was used to accurately map any deformation inside
the 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 is taken.
Figure 4-7. Profile Plotter Setup
The liner was placed inside a circular polyvinyl chloride (PVC) tube, as if it was inside a host pipe, 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 1 in. apart and averaged. The liner was
found to be approximately circular with reference to its center (green line in Figure 4-8). On the spring
line to spring line plane, the liner had a slightly larger diameter than on the crown-invert plane, most
likely due to geometrical imperfections in the original host pipe. The percent ovality based on the ovality
definition in ASTM F1216 is 5.07%. The red and blue lines are shown in connection with the liner
buckling test that was carried out on this liner and which is described in Section 4.2.12. When a host
and/or liner are oval in shape, the larger radius of curvature in the flatter section of the oval liner reduces
the ability of the liner to resist external buckling pressures. This is taken into account in the design
equations for the liner in ASTM F1216. When pipe ovality exceeds 5%, the structural impact on liner
strength becomes more significant.
30
-------
Profile Plot
Red - Steel tube Green - Pre-buckling Blue - post-buckling
Figure 4-8. Ovality of the Denver 8-in. Liner (Average of Three Cross-Sections Spaced 1 in. Apart)
4.2.11 Flexural Testing and Tensile Testing. Flexural testing on specimens taken from the 8-in.
Denver liner was carried out both by TTC and Insituform (the supplier of the original CIPP liner). The
test preparations and results are described in detail for the TTC testing and these are then compared with
the results provided by Insituform from their testing.
At TTC, specimens as described in ASTM D790 and D638 were cut from the crown, spring line, and
invert of the retrieved CIPP liner using a router and a band saw. A total of nine specimens were prepared
and tested (three from each location). The sides of specimens were smoothed using a grinder. The water
jet cutter could not be used as the dimensions of the liner cutouts were too small to hold inside the cutting
board. The specimens were marked as shown in Figure 4-9 and Table 4-6. The laboratory set-ups for the
flexural and tensile testing are shown in Figures 4-10 and 4-11, respectively. The results of the flexural
and tensile testing for the Denver 8-in. liner are summarized in Tables 4-7 to 4-9 and Figures 4-12 to 4-
13.
31
-------
Figure 4-9. Liner Specimens - Bending (Left) and Tensile (Right) (Denver 8-in. Liner)
Table 4-6. Marking of Specimens (Denver 8-in. Liner)
Location
From the crown
From the spring line
From the invert
Sample ID
Crown 1; Crown 2; Crown 3
SL1;SL2;SL3
Invert 1; Invert 2; Invert 3
Figure 4-10. Flexural Testing in Accordance with ASTM D790
Figure 4-11. Tensile Testing Specimens Before (Left) and After the Test (Right)
-------
Table 4-7. Results from Flexural Testing (Denver 8-in. Liner)
Location
on pipe
Crown 1
Crown 2
Crown 3
Average
SL1
SL2
SL3
Average
Invert 1
Invert 2
Invert 3
Average
Overall
Average
Peak load
Ob)
36.63
39.24
36.95
-
29.00
33.62
31.29
-
33.29
32.06
36.73
-
-
Peak bending stress
(psi)
6,316
6,329
6,718
6,454±228
6,170
7,309
6,657
6,712±571
7,083
6,412
7,815
7,103±702
6,756±546
Peak shear stress
(psi)
251
254
271
259±11
243
275
264
260±16
283
256
308
282±26
267±20
Flexural
modulus
(psi)
331,269
310,634
347,401
329,768±18,429
322,611
359,245
338,276
340,044±18,381
319,351
325,894
363,382
336,209±23,759
335,340±18,186
Table 4-8. Results from Tensile Testing (Denver 8-in. Liner)
Location on Pipe
Crown 1
Crown 2
Crown 3
Average
SL1
SL2
SL3
Average
Invert 1
Invert 2
Invert 3
Average
Overall average
Area
(in.2)
0.1327
0.1344
0.1351
-
0.1607
0.1437
0.1462
-
0.1325
0.1452
0.1493
-
-
Peak Load
(lb)
430.47
417.85
376.52
447.55
459.14
437.34
407.38
465.17
428.88
-
-
Peak Stress
(psi)
3,244
3,109
2,787
3,047±235
2,785
3,195
2,991
2,990±205
3,075
3,204
2,873
3,051±167
3,029±179
Mod. E
(psi)
405,111
479,861
350,396
411,789±64,990
401,369
400,884
400,954
401,069±262
389,787
473,405
402,825
422,006±44,988
411,621±40,548
33
-------
Flexural Stress Vs Flexural Strain
8000
7000
6000
sooo
4000
0.01 0.02 0.03 0,04
Flexural Strain, in/in
0.01>
0.06
8000
7000
6000
5000
4000
3000
2000
1000
0
Flexural Stress Vs Flexural Strain
0.01 0.02 0.03 0.04
Flexural Strain, in/in
0.05
0.06
9000
8000
"-"300
6000
5000
4000
3000
2000
1000
0
Flexural Stress Vs Flexural Strain
zz
0.01 0.02 0.03 0.0^
Flexural Strain, in/in
Invert 1
In vert 2
Inverts
o.OS
0.06
Figure 4-12. Stress-Strain Curves from Flexural Testing of Specimens (Denver 8-in. Liner)
34
-------
Table 4-9. Comparison of Test Data from TTC and Insituform
Mean
Std. Dev
Tensile Break
Strength
(psi)
TTC*
3,244
3,109
2,787
2,785
3,195
2,991
3,075
3,204
2,873
3,029
179
Insitu
Form
2,500
2,400
2,100
-
-
-
-
-
-
2,333
208
Tensile Modulus
E
(psi)
TTC
405,111
479,861
350,396
401,369
400,884
400,954
389,787
473,405
402,825
411,621
40,548
Insitu
Form
-
-
-
-
-
-
-
-
-
-
-
Tensile Elong.
at Break
(%)
TTC
2.0
3.5
4.5
1.5
3.3
3.4
2.0
3.5
4.5
3.1
1.1
Insitu
Form
2
1
1
-
-
-
-
-
-
1.3
0.6
Flexural Break
Strength
(psi)
TTC
6,316
6,329
6,718
6,170
7,309
6,657
7,083
6,412
7,815
6,757
546
Insitu
Form
7,400
7,000
6,500
6,400
7,300
-
-
-
-
6,920
455
Flexural
Modulus E
(psi)
TTC
331,269
310,634
347,401
322,611
359,245
338,276
319,351
325,894
363,382
335,340
18,186
Insitu
Form
520,000
530,000
470,000
430,000
520,000
-
-
-
-
494,000
42,778
Barcol
Hardness (Inner)
Type D 934-1
TTC
43
39
39
-
-
-
-
-
-
40
4
Insitu
Form
40
35
35
41
39
-
-
-
-
38
3
Specific
Gravity
TTC
1.16
-
-
-
-
-
-
-
-
1.16
-
Insitu
Form
1.19
1.18
1.19
1.19
1.19
-
-
-
-
1.19
0
* The sample that was sent to Insituform was a piece of the host pipe with the liner inside. The liner extended a few inches on each of the host
pipe joint.
-------
3500
3000
2500
2000
1500
1000
500
Tensile Modulus of Elasticity
o.oi
0.02 0.03
Strain, in/in
0.04
0.05
Tensile Modulus of Elasticity
3500
3000
2500
2000
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04
3500
Tensile Modulus of Elasticity
o.oi
0.02 0.03
Strain, in/in
0.04
0.05
Figure 4-13. Stress-Strain Curves from Tensile Testing of Specimens (Denver 8-in. Liner)
36
-------
4.2.12 Buckling Test. A steel mechanical tube was prepared for the test to act as a host pipe for the
liner. The tube was 2 ft long and machined to accommodate the slight ovality of the liner (the tube
thickness was reduced 1/16 in.). Two 3/8 in. threaded holes were made on the opposite sides of the
mechanical tube. Quick connectors were fixed to the pipe through the holes to allow attaching the
pressure system (see Figure 4-14).
The liner was inserted into the tube by manually pushing it into place. IPEX™ pipe joint lubricant was
applied to the inside of the tube to ease the sliding of the liner. The liner was beveled on both ends using
an air operated disk sander, and finished flush with the end of the pipe (Figure 4-15).
Threaded Hole
Figure 4-14. Machined Mechanical Tube (Left) and a Threaded Hole on the Tube (Right)
Figure 4-15. Liner Inside the Pipe and Beveling of the Liner
37
-------
Two specially designed, open-ended, conical steel caps filled with high temperature silicon and polyurea
were prepared and used to maintain the seal at the ends of the test specimens (Figures 4-16 and 4-17).
The caps were pressed against each end of the pipe specimen using threaded rods and were designed to
ensure that the annular space between the inner wall of the pipe and outer wall of the liner was sealed.
This high level of effort and precision was considered paramount to allow effective sealing of the annulus
under elevated internal pressure, while allowing free access to the interior of the pipe for conducting
frequent deformation measurements of the liner.
A pressure gage was connected to one of the threaded holes and the other was fitted with a quick
connector for applying water pressure (Figure 4-18). A nitrogen gas pressure bladder system was used to
convert normal water supply pressure to a high water pressure for the testing (4-19).
Outer
Flange
Inner
Flange
Front View
Outer
Flange
Liner
Inner
Flange
Polyurea
Figure 4-16. Drawing of a Pressure Cap
Figure 4-17. Experimental Setup Showing the Threaded Rod
38
-------
Figure 4-18. Pressure Gage and Pressure Application Installed on the System
Figure 4-19. Nitrogen Gas Pressure Bladder System for Supplying the Test Pressure
A profile plotter developed at TTC was used to monitor the
profile of the interior of the liner both before and after
testing (see Figure 4-20). This system is equipped with an
LVDT rotating a full circle in one and one-half minutes.
The voltage reading changes as the tip of the LVDT moves
and those readings were collected using a HP 3479A data
acquisition system (DAQ). Later, the readings were
processed to obtain the actual profile of the inside of the
liner. It was difficult to use the profile plotter during the
test itself due to the probability of water splash inside the
liner and a rapid liner buckling at failure. However, a post
buckling profile was obtained and is shown in Figure 4-8.
Figure 4-20. Profile Plotting -
LVDT Rotating on the Inner
Circumference
39
-------
Although there were some leaks during the test, the liner held 40 to 45 psi (equivalent to 92 to 104 ft of
water head) for approximately 1 hour in total. The applied pressure spiked during the test to a value of
200 psi, but was quickly reduced again to the 40 to 45 psi range (Figure 4-21).
Even with the brief peak at 200 psi pressure, visible evidence did not show a buckling failure of the liner
although there was evidence of water leaks through the liner that indicated some localized failures
(Figure 4-22).
Figure 4-21. Pressure on the Liner at Intervals During the Test
Figure 4-22. Localized Leak on the Liner - Green Spots Due to Green Food Color
40
-------
4.2.13 Shore D Hardness. Durometer (Shore) hardness (ASTM D2240) is used to determine the
relative hardness of soft materials, such as thermoplastic and thermosetting materials. This test measures
the penetration of a specified indenter into the subject material under specified conditions offeree and
time.
Specimens measuring approximately 1 in. x 1 in. were cut from the crown, spring line, and invert of the
retrieved CIPP liner using a band saw. All Shore tests were performed using the Shore D hardness scale,
which utilizes a weight of 10 Ib (4,536 g) and a tip diameter of 0.1 mm. A total of 144 readings were
performed on samples taken from the crown, spring line, and invert. Tests were conducted on the inner
and outer surfaces. The average recorded values are shown in Figure 4-23 and the recorded values are
rounded to integer values in the discussion below. It can be seen that there is a progression of increased
hardness from the inner invert surface of the liner (56), through the inner spring line surface (59) to the
inner crown surface of the liner (63). The outer side of the liner enclosed by the host pipe was neither in
contact with the soil nor with the waste stream, and provided hardness values of between 74 and 80 with
an average of 77. This is approximately 38% higher than the inner invert surface and still significantly
(22%) higher than the inner crown surface. This could suggest that the constant contact with the waste
stream might result in progressive softening of the liner material (although some differences in hardness
may be caused by the presence or eroded condition of the polyurethane layer). It is also not clear at the
moment as to how a rougher surface that has been subjected to erosion may compare with a previously
smooth surface even if there are no chemical changes involved. The hardness results are compared with
the other liner tests and across all the retrospective sites in Section 6.
4.2.14 Barcol Hardness. In addition to the Shore hardness tests, tests were conducted using the
Barcol hardness test (ASTM D2583) which uses a spherical-ended indenter. This allowed comparison
with the hardness testing conducted by Insituform and the results and comparison are shown in Table 4-9.
The TTC Barcol hardness results are shown in Figure 4-24. The results for the inner surface of the liner
showed less differences between the crown, spring line, and invert (average values of 43, 39 and 39,
respectively [rounded to integer values]) than the Shore D hardness testing. The outer surface results for
the crown, spring line, and invert were 46, 39 and 42, respectively. The differences between the inner and
outer surface values at the crown, spring line, and invert were 6%, 2% and 9%, respectively, with the
outer surface always having the higher value. In the Barcol testing, the average outer surface value of 42
is 8% higher than the inner invert surface value of 39. Overall, the TTC results involving 972
measurements gave a mean Barcol hardness of 41 ±5 and the Insituform testing of five measurements
gave a mean Barcol hardness of 38±3. The average of all the TTC inner surface readings gave a mean
Barcol hardness of 40±4. Interpretation of the hardness results across all of the sites is provided in
Section 6.
Since a surface hardness test is simple and quick to perform, and it might serve as a basis for a non-
destructive in-situ test for CIPP liners, the TTC is planning to conduct additional Shore and/or Barcol
hardness tests on a number of recently cured CIPP specimens that employ different types of resins to
explore possible relationships.
41
-------
HI
c
-o
0
-------
Denver 8-in.
Crown
D Inner surface (left) Weighted average 43.211.5
Q Outer surface (right) Weighted average 45.9 1 1.2
60
50
is 4°
c
•a
ra 30
1 -
CO
10
0 -
Specimen
ra
.c
Denver 8-in.
Spring Line
D Inner surface (left) Weighted average 3S.5 ± 0.9
• Outer surface (right) Weighted average 39.4 ±1.2
60
50
40
30
i5 20
m
10
o
Specimen
Denver 8-in.
Invert
D Inner surface (left) Weighted average 38.9 ± 1.3
D Outer surface (right) Weighted average 42.310.8
60
50
| 40
Jj 30
-Q
h 20
m
10
Specimen
Figure 4-24. Barcol Hardness Readings for the Liner's Inner and Outer Surfaces
(Denver 8-in. Liner)
43
-------
4.2.15 Raman Spectroscopy. Raman spectroscopy was used to assess the liner material's degree of
aging. The specimens used were 1A in. x !/2 in. as only a very small surface area of the sample is required
for collecting Raman spectra. The specimens were polished using a mechanical polisher and cleaned with
distilled water.
Raman spectroscopy is a technique based on inelastic scattering of monochromatic light, usually from a
laser source. Inelastic scattering refers to change in the frequency of photons in the monochromatic light
upon interaction with a sample. Photons of the laser light are absorbed by the sample and then reemitted.
The frequency of the reemitted photons is shifted in comparison with the original monochromatic
frequency, a phenomenon called the "Raman Effect". This shift provides information about vibrational,
rotational, and other low frequency transitions in the molecules, which are indicators of degradation and
breakdown of the resin at its most fundamental (molecular) level.
Spectra from 200 to 2100 cm"1 were collected using an R-3000 HR Raman spectrometer utilizing a 785
nm diode laser operating at 290 mW via a fiber optic probe. Integration time was 30 seconds. As shown
in Figure 4-25, the measured intensity of the Raman signal in arbitrary units (a.u.) is plotted on the y-axis,
while the wave length in cm1 is plotted on the x-axis.
The plots are nearly identical for the base resin and liner used for 25 years, with no significant change in
the intensity of the peaks or region shift, indicating high chemical stability. Additional tests were carried
out on the exterior surface of the liner, but no significant changes from the spectra shown in Figure 4-25
were detected.
Denver 8-in.
-2-
^
0)
-------
increases and the heat of cure decreases. These changes can be used to characterize and quantify the
degree of cure of the resin system (Perkins-Elmer, 2000).
Four samples of the CIPP liner labeled crown, spring line, invert, and virgin resin material were tested.
The Tg determination followed ASTM E1356-08 "Standard Test Method for Assignment of the Glass
Transition Temperatures by Differential Scanning Calorimetry." The mass of each sample was measured
with a Mettler AT261 Delta Range balance and calorimetry was conducted with a Perkin Elmer Diamond
DSC that includes an Intracooler cooling accessory. The DSC was calibrated per manufacturer's
specifications using indium and zinc standards. The DSC testing is summarized in Table 4-10.
Table 4-10. Perkin Elmer Diamond DSC Testing Parameters
Sample Pans
Aluminum Pans
Testing Environment
Nitrogen
Temperature Program
1. Heat from -40° C to 225° Cat 10°
C/min
2. Hold for 10 minutes at 225° C
3. Cool from 225° C to -40° C at 20°
C/min
4. Hold for 5 minutes at -40°C
5. Heat from -40° C to 225° Cat 10°
C/min
Glass transition, Tg, values were calculated based on the methodology described in ASTM E1356-08
using the midpoint temperature, Tm, of the extrapolated onset and end temperatures of the transition
range. The midpoint temperature is the most commonly used as the glass transition temperature as it has
been found to have higher precision and is more likely to agree with the Tg measured by other methods.
Minimal gravimetric loss was observed (approximately 3.5% of weight or less) as a result of the imposed
thermal cycle indicating, that the samples were thermally stable over the range of temperatures evaluated.
The gravimetric data is summarized in Table 4-11.
Table 4-11. Gravimetric Data for DSC Test (Denver 8-in. Liner)
Sample
Invert
Invert
Crown
Crown
Spring line
Spring line
Virgin Resin
Virgin Resin
Run
1
2
1
2
1
2
1
2
Sample Weight
(mg)
7.19
8.89
10.45
13.89
12.05
10.86
6.68
14.88
Post Analysis Weight
(mg)
7.11
8.65
10.21
13.8
11.7
10.48
6.63
14.82
Weight
loss (%)
1.1
2.7
2.3
0.6
2.9
3.5
0.7
0.4
45
-------
As summarized in Table 4-10, the initial thermal program (steps 1-4) was performed to remove any
previous thermal history. The final heat scan step (step 5) of the temperature program was used for
quantification as this scan contains a known thermal history. The calculated Tg values are summarized in
Table 4-12.
Table 4-12. Sample Tg Determination (Denver 8-in. Liner)
Sample
Invert
Invert
Crown
Crown
Spring line
Spring line
Virgin Resin
Virgin Resin
Run
1
2
1
2
1
2
1
2
Tg (°C)
122.65
117.52
122.31
119.11
134.63
129.76
123.57
124.59
The average Tg for the control samples was 124.08°C (+/- 0.72°C) and the average Tg for the field
samples was 124.33°C (+/- 6.57°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 (Perkins-Elmer, 2000). The Tg results suggest a similar level of curing between the virgin resin
(control sample) and the aged material samples, with the field samples exhibiting slightly higher
variability in Tg values from the spring line to invert.
4.2.17 CCTV Inspection of Area Sewers for Denver 8-in. Site. The City of Denver ordered
CCTV scans of the lines in the area from which the sample was retrieved. Also, historical maintenance
reports of these lines were requested. A total of nearly 5,800 ft of sewer line was imaged in the period
September 24-28, 2009. A preliminary review of the CCTV reports suggested that the liner is in good
condition overall. Several tap break-in defects were noted as well as lining failure at undercut
connections, which could allow for root intrusion between the lateral outer wall and the liner covering the
interior of the main pipe. This could be attributed to the robotic cutters used by the industry 25 years ago,
which were far less sophisticated and accurate than the units used today. Some of the images reveal root
intrusion via tap connections, resulting in a partial blockage of the sewer line, but the liner itself appears
to be intact in these images. On the line stretch in the alley between Garfield Street and Jackson Street
(between 3rd and 4th Avenues), at chainage 212.6 ft, there is what appears to be a liner failure in the
vicinity of a tap break in. Another liner failure was found at the alley between Jackson Street and
Garfield Street, from the first manhole north to the first manhole south to 1st Avenue. At chainage 20.8 ft,
a bulge was found at the invert of the liner that prevented further advancement of the CCTV equipment.
A third liner failure location was identified in the line running in the alley between Jackson and Harrison
Streets, as it crosses 3rd Avenue, at chainage 239.8 ft. This liner failure appears to be attributed to
improper restoration of a nearby lateral connection. A significant portion of the polyurethane coating was
hydrolyzed along this line. A lining failure attributed to a connection cut shift was noted at 2nd Avenue
and Jackson Street. Similar occurrences of a liner connection cut shift were noted on a couple of other
lines. A location where the liner appears to be detached from the host pipe was located at chainage 39 ft,
in the alley between 3rd Avenue and Garfield Street.
46
-------
In summary, CCTV inspection of three parallel 8-in. VCP sewer lines lined using the CIPP lining method
in the mid to late 1980s, was completed. All sewer lines run in the allies between Monroe and Garfield
Streets (Line 'A'), Garfield and Jackson Streets (Line 'B'), and Jackson and Harrison Streets (Line 'C').
The survey area was bound at the south end by Ellsworth Avenue and at the north end by 5th Avenue. In
total, 5,797 linear feet of CIPP lined pipe were imaged. A number of defects in the liner were noted by
the operator. With the exception of three locations, all defects appear to be related to poor restoration of
the lateral connections following lining of the mainline, which in some cases allowed for root intrusion
between the outer wall of the lateral and the liner. Another liner defect which was noted on multiple
occurrences was a connection tap shift, potentially due to relative movement of the lateral with respect to
the mainline or movement of the liner within the host pipe. Three liner defect events were identified that
are not related to the restoration of a lateral connection: (1) a bulge in the liner, (2) a detachment of the
liner from the host pipe wall, and (3) what appears to be a tear in the liner, possibly due to inaccurate
lateral restoration attempt (cut is located approximately 1.5 in. from the edge of a lateral connection).
4.3
Site 2: 48 in. Equivalent Diameter Egg-Shaped Brick Sewer
4.3.1 Host Pipe and Liner Information. A 48-in. diameter brick sewer pipe, originally installed
in the early 1900s near Union Station in Denver, CO, was relined with a CIPP liner in 1987 under Denver
Project PCO-609 Union Station. The CIPP-repaired section lies under 19th Street (see Figure 4-26).
Manhole MH B-3 located at the crossing of the 19th Street and Wynkoop Street divides the rehabilitated
section into two parts: the lining thickness was 18 mm upstream (270 ft length between manholes B-l and
B-3) and 13.5 mm downstream (186 ft length between manholes B-3 and B-5).
KH- B7«.m».K! NOT « U.-
MH-BKBtgln Lin* *B*>
' .00
-w
/a i
Upstream 5
sample (18 mm) *
Downstream
sample (13.5 mm)
Figure 4-26. Layout and 2010 Sample Locations for the Denver 48-in. Liner
4.3.2 Sample Removed and Tested in 1995. Insituform Technologies removed one sample from
the installed CIPP liner and tested it in 1995 (at the time the liner was eight years old). The sample was
taken from adjacent to manhole B3 and the liner thickness was measured to be 18 mm. Test methods for
tensile testing were based on ASTM D638 and for flexural testing based on ASTM D790. The results are
shown in Table 4-13. It should be noted that there was some confusion about the data recorded for the
sample in that the 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 flexural strength
47
-------
(average of 6,900 psi) and flexural modulus of elasticity (average of 490,000 psi) were both well above
the specified values at the time of installation (4,500 psi and 250,000 psi, respectively). Overall
comparisons can be found in Section 6.
Table 4-13. Historic Sampling Results for the CIPP Liner Tested in 1995 (Denver 48-in. Liner)
Sample
1
2
o
3
4
5
Mean
Std Dev
Tensile
Break
Strength
(psi)
2,500
2,400
2,100
-
-
2,300
170
Tensile
Elongation
at Break
(%)
1.8
1.3
1.3
-
-
1.5
0.2
Flexural
Break
Strength
(psi)
7,400
7,000
6,500
6,400
7,300
6,900
400
Flexural
Modulus of
Elasticity
(psi)
520,000
530,000
470,000
430,000
520,000
490,000
40,000
4.3.3 Sample Retrieval in 2010. Two samples, each approximately 2 ft * 2 ft, were exhumed
from the installed liner on May 20, 2010, by Wildcat Civil Services of Kiowa, CO with Jack Row, the
General Superintendent, on site. (The liner age at this time was 23 years.) Both samples were taken from
the crown of the pipe at a distance about 4 ft from manhole B-3 (one upstream and the other downstream
of the manhole). The samples were sent to TTC for testing. Figure 4-27 shows images of the recovered
specimens.
4.3.4
Figure 4-27. Images of the Recovered Samples from the Denver 48-in. Liner
Annular Gap. Annular space measurements were not collected for this sample due to the
;es of sanmle retrieval.
circumstances of sample retrieval
4.3.5 Liner Thickness
4.3.5.1 Downstream Sample. For determining the liner thickness of the downstream sample, 10
readings were taken at six different locations around the sample (a total of 60 readings) using a
micrometer with a resolution of ±0.0001 in. The average calculated values and their standard deviations
are shown in Figure 4-28. The weighted average for the sample thickness measurements was calculated
to be 13.9 mm and the weighted error ±0.3 mm.
48
-------
Denver48-in. Downstream
16.0
Designedthickness 13.5 mm
Weighted average 12.50 mm ± 0.28 mm
10.0
SI S2
Measured specimens
S5
S6
Figure 4-28. Thickness for Denver 48-in. Downstream Sample
4.3.5.2 Upstream Sample. For determining the liner thickness of the upstream sample, an 18 in. x
18 in. panel was cut into nine squares (6 in. x 6 in.) and thickness was measured along the edges. Three
'inner' squares were next cut into four squares each, and again thickness was measured along the edges.
In summary, a total of 18 sets of readings were taken, where each set contained 10 readings, amounting to
a total of 180 readings. The average calculated values and their standard deviations are shown in Figure
4-29. The weighted average for the sample thickness measurements was calculated to be 14.2 mm and
the weighted error ±0.2 mm.
Denver 48-in. Upstream
E
E
O)
c
_~
22.0
21.0
20.0
19.0
18.0
17.0
16.0
15.0
14.0
13.0
12.0
Designed thickness 18 mm
Weighted average 14.16 mm ±0.27 mm
rrm i i i
Mil i i i i
SI S2 S3 S4 S5 S6 S7 S8 S9 S10 Sll S12 S13 S14 SIS S16 S17 SIS
Measured specimens
Figure 4-29. Thickness for Denver 48-in. Upstream Sample
49
-------
4.3.6
Specific Gravity and Porosity
4.3.6.1 Introduction. Specific gravity was measured by the displacement method in accordance with
ASTM D792. The standard specifies that any convenient size specimen can be used for this testing. A
weighing scale (Figure 4-30) fitted with a hook at the bottom was placed on a bench having a circular
hole in the middle. A small wire basket was hung from the hook (Figure 4-31). A thermometer to
measure the water temperature was hung from the bottom of the bench.
Figure 4-30. Weighing Scale, Model
Mettler PM200
Figure 4-31. Wire Basket and Thermometer
A bucket full of water was placed on top of a screw jack. The screw jack helped in elevating the bucket
and immersing the specimen in water. A sinker was also used to sink the specimens. Details of the
instrumentation are shown in Figure 4-32.
Figure 4-32. ASTM D792 Setup
The weight of each specimen was measured in air and water. The weight of the wire basket was also
measured in water. Each time the immersed depth for the wire basket was kept identical. Specific gravity
was calculated for each specimen using the equation provided in ASTM D792.
The bulk specific gravity of the liner comprises a mixture of resin, fabric, coating, and air. It is a useful
measure to check whether the liner meets the theoretical specific gravity based on the weighted
contribution of its components. Low specific gravities typically indicate higher porosities in the liner.
The results of the specific gravity measurements across all of the liners tested are discussed in Section 6.
50
-------
4.3.6.2 Downstream Sample. Seven specimens from the downstream sample were used in this test.
The average specific gravity for the sample was calculated to be 1.07 and standard deviation 0.04.
In addition to the TTC laboratory measurements of specific gravity, measurements of density and porosity
of a sample from this liner specimen were made by Micrometrics Analytical Services. In its testing
(using mercury penetration for the porosity determination), the bulk density (at 0.54 psia) was
1.1645 g/mL, the apparent (skeletal) density was 1.3123 g/mL, and the porosity was 11.262%. The full
test report is provided in Appendix C.
4.3.6.3 Upstream Sample. Seven specimens from the upstream sample were used in the TTC testing
for specific gravity. The average specific gravity for the sample was calculated to be 1.08 and standard
deviation 0.03.
In addition to the TTC laboratory measurements of specific gravity, measurements of density and porosity
of a sample from this liner specimen were made by Micrometrics Analytical Services. In its testing
(using mercury penetration for the porosity determination), the bulk density (at 0.54 psia) was
1.1618 g/mL, the apparent (skeletal) density was 1.2933 g/mL, and the porosity was 10.171%. The full
test report is provided in Appendix C.
4.3.7
Flexural Testing
4.3.7.1 Downstream Sample. Specimens were cut from the retrieved downstream CIPP liner sample
in accordance with ASTM D790 for measuring the liner's flexural strength and flexural modulus of
elasticity. A total of five specimens were prepared and tested. The sides of the specimens were smoothed
using a grinder and a table router. The water jet cutter could not be used due to curvature of the liner.
Testing was performed using an ADMET eXpert 2611 Universal Testing Machine (UTM) as shown in
Figure 4-33. Table 4-14 lists the dimensions and moment of inertia for all specimens. Table 4-15 and
Figure 4-34 summarize the flexural test results for the Denver 48-in. downstream sample.
Figure 4-33. Flexural Test in Accordance with ASTM D790
51
-------
Table 4-14. Geometric Data for Flexural Test Specimens (Denver 48-in. Downstream Sample)
Sample
ID
1
2
3
4
5
Span
(in.)
4
4
4
4
4
Dimension
W (in.)
0.495
0.512
0.500
0.496
0.517
D (in.)
0.523
0.500
0.500
0.532
0.513
Moment of Inertia
(in.4)
0.005901
0.005333
0.005208
0.006224
0.005816
Using the information in Table 4-14, the following figures were drawn:
• Load data and deflection data at mid-point for all samples.
• Flexural stress and strain graphs for all samples.
Peak load, peak shear stress, and flexural modulus were obtained from the software 'MtestW that
operates the ADMET eXpert 2611 UTM. Peak bending stress is calculated from the peak load value
achieved using the following formula.
where
= Bending stress
P = Peak load
L = Span length
D = Depth of the specimen
/ = Moment of inertia of area
Table 4-15. Flexural Test Results for Denver 48-in. Downstream Sample
Location on
Pipe
1
2
3
4
5
Average and
Std. Dev.
Peak Load
(Ib)
155
158
154
161
150
-
Peak Bending
Stress
(psi)
6,873
7,418
7,371
6,867
6,628
7,031±346
Peak Shear
Stress
(psi)
599
618
614
609
567
601±21
Flexural
Modulus
(psi)
340,145
290,124
314,932
282,343
287,254
302,960±24,303
52
-------
Flexural Stress Vs Flexural Strain
8000
7000
6000
5000
V
I
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09
Flexural Strain, in/in
Figure 4-34. Flexural Stress-Strain Curves for Denver 48-in. Downstream Sample
4.3.7.2 Upstream Sample. Specimens were cut from the retrieved upstream CIPP liner and tested for
flexural strength and flexural modulus of elasticity in the same manner as specimens from the
downstream sample (Table 4-16). The results of testing are provided in Tables 4-17 and 4-18 and Figures
4-35 and 4-36.
For this particular set of samples, the flexural test results, particularly the flexural modulus, were
unusually low compared to the other samples tested in this project. It was decided to repeat a new set of
five samples to see if an error in the testing procedures or a localized weak spot in the liner might have
caused the low values. The original test results are termed "Set 1" and the repeated tests are termed "Set
2". It can be seen that there is a significant difference between the two sets of results with the second set
meeting all of the ASTM minimum values for a new liner and the first set meeting the peak bending stress
value, but falling significantly below on the flexural modulus. It appears most likely that the area of the
liner used for the first set of tests was of poorer quality than for the second set of tests. The interpretation
of these results in comparison with the test results for all the retrospective sites is discussed in Section 6.
Table 4-16. Geometric Data for Flexural Test Specimens for Denver 48-in. Upstream Sample
Sample
ID
1
2
3
4
5
Span
(in.)
4
4
4
4
4
Dimension
W (in.)
0.490
0.470
0.478
0.534
0.518
D (in.)
0.540
0.540
0.558
0.556
0.568
Moment of Inertia
(in.4)
0.0064298
0.0061673
0.0069207
0.0076486
0.0079103
53
-------
Table 4-17. Flexural Test Results for Denver 48-in. Upstream Samples (Set 1)
Location on
Pipe
1
2
3
4
5
Average and
Std. Dev.
Peak Load
(Ib)
107.56
105.26
112.76
156.45
161.59
-
Peak Bending
Stress
(psi)
4,517
4,608
4,546
5,686
5,801
5,032±652
Peak Shear
Stress
(psi)
407
415
423
527
549
464±68
Flexural
Modulus
(psi)
169,445
168,437
167,678
221,749
185,801
182,622±23,126
Q.
«-
a
&
a
1
7000
Flexural Stress Vs Flexural Strain
o.oi
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
Flexural Strain, in/in
Figure 4-35. Flexural Stress-Strain Curves for the Denver 48-in. Upstream Liner (Set 1)
54
-------
Table 4-18. Flexural Test Results for Denver 48-in. Upstream Samples (Set 2)
Location on
Pipe
1
2
3
4
5
Average and
Std. Dev.
Peak Load
(Ib)
139
156
149
162
167
-
Peak Bending
Stress
(psi)
5,012
6,027
7,486
6,159
5,900
6,117±888
Peak Shear
Stress
(psi)
476
559
589
541
540
541±41
Flexural
Modulus
(psi)
276,920
187,218
369,998
270,265
214,134
263,707±70,398
~
Q.
Flexural Stress Vs Flexural Strain
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
0.01 0.02 0.03 0.04 0.05 0.06
Flexural Strain, in/in
0.07
0.08
0.09
4.3.8
Figure 4-36. Flexural Stress-Strain Curves for Denver 48-in. Upstream Liner (Set 2)
Tensile Testing
4.3.8.1 Downstream Sample. Specimens were cut from the retrieved downstream CIPP liner sample
in accordance with ASTM D638 (see Figure 4-37) for measuring the liner's tensile strength. A total of
five specimens were prepared and tested. The results of testing are shown in Table 4-19.
Using the information given in Table 4-19, the stress-strain curves for all samples were drawn, as shown
in Figure 4-38.
55
-------
Figure 4-37. Tensile Specimens for Denver 48-in. Downstream Sample: Before the Test (Left) and
Following the Test (Right)
Table 4-19. Tensile Test Results for Denver 48-in. Downstream Sample
Location on
Pipe
1
2
3
4
5
Average and
Std. Dev.
Area
(in.2)
0.2733
0.2611
0.3203
0.2888
0.3467
-
Peak Load
db)
785.36
813.76
862.47
867.73
1139.19
-
Peak Stress
(psi)
2,874
3,117
2,693
3,005
3,286
2,995±227
Tensile Modulus
(psi)
405,345
364,283
405,639
288,786
448,047
382,420±60,141
3500
3000
2500
2000
Tensile Modulus of Elasticity
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
0.02
0.04 0.06
Strain, in/in
0.08
0.1
Figure 4-38. Stress-Strain Curves from Tensile Testing for Denver 48-in. Downstream Sample
56
-------
4.3.8.2 Upstream Sample. Specimens were cut from the retrieved upstream CIPP liner and tested for
tensile strength in the same manner as specimens from the downstream sample. The results of testing are
provided in Table 4-20 and shown in Figure 4-39.
Table 4-20. Tensile Test Results for Denver 48-in. Upstream Sample
Location
on Pipe
1
2
o
3
4
5
Average
Area
(in.2)
0.3052
0.2641
0.2822
0.2991
0.2846
-
Peak Load
(Ib)
923
858
904
1064
856
-
Peak Stress
(psi)
3,023
3,250
3,203
3,557
3,009
3,208±222
Tensile Modulus
(psi)
451,779
431,712
324,920
466,379
459,145
426,787±58,396
,t
s
Tensile Modulus of Elasticity
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
0.01
0.02
0.03
Strain,in/in
0.04
0.05
0.06
Figure 4-39. Stress-Strain Curves from Tensile Testing of Denver 48-in. Upstream Samples
4.3.9
Shore D Hardness
4.3.9.1 Introduction. The Durometer (Shore D) hardness test (ASTM D2240) is used to determine
the relative hardness of soft materials, such as thermoplastic and thermosetting materials. This test
measures the penetration of a specified indenter into the subject material under predetermined force and
time. The Shore D hardness scale utilizes a weight of 10 Ib (4,536 g) and a tip diameter of 0.1 mm. For
the purpose of interpreting the results, a Shore D hardness scale value of 50 represents the hardness of a
solid tire (e.g., similar to those used by forklifts), while a value of 80 represents the hardness of paper-
making rollers.
57
-------
4.3.9.2 Downstream Sample. Specimens measuring approximately 1 in. x 1 in. were cut from the
retrieved downstream sample of the CIPP liner using a band saw. A total of 10 specimens were prepared
and tested. A total of 36 tests were conducted on each sample: 18 tests on the inner surfaces and 18 tests
on the outer surfaces. The average calculated values and their standard deviations are shown in Figure 4-
40. The average and standard deviation of the Shore D hardness for the sample inner surface was
calculated to be 65±3 and for the outer surface 79±2. The differences between the inner and outer
surfaces of the liner follow the same pattern as the reading for the Denver 8-in. liner. The outer side of
the liner enclosed by the host pipe was neither in contact with the soil nor with the waste stream. The
significance of this result is explored in Section 6.
Denver 48-in. Downstream
mr™* surface
6 outer surface
Weighted average 65.213.4
Weighted average 78.9 ±1.6
90
Figure 4-40. Shore D Hardness for Denver 48-in. Downstream Sample
4.3.9.3 Upstream Sample. A total of seven specimens were prepared and tested. A total of 50 tests
were conducted on each sample: 25 tests on the inner surfaces and 25 tests on the outer surfaces. The
average calculated values and their standard deviations are shown in Figure 4-41. An average of 25
readings at both the inner and outer surface of each of seven specimens is shown. The weighted average
and standard deviation of the Shore D hardness for the sample inner surface was calculated to be 47±2
and for the outer surface 63±3.
Denver 48-in. Upstream
D inner surface Weighted average 46.59 ± 2.3
• outer surface Weighted average 62.7 + 3.1
100
Figure 4-41. Shore D Hardness for Denver 48-in. Upstream Sample
58
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4.3.10
Barcol Hardness
4.3.10.1 Downstream Sample. Seven specimens from the exhumed downstream sample were
subjected to the Barcol test (ASTM D2583). Due to the presence of dust and debris on the outer wall of
the exhumed CIPP slabs (Figure 4-42), a belt sander was used to achieve a smooth surface. The inner
surface of each sample was kept unaltered (Figure 4-43). A wooden base was prepared to match the
thickness of the specimens, and the Barcol hardness tester (Figure 4-44) was placed on that platform to
conduct the test (Figure 4-45).
Figure 4-42. Original Outer Surface
(Denver 48-in. Downstream Sample)
Figure 4-43. Smoothed Outer Surface (Top Row) and
Inner Surface (Bottom Row)
(Denver 48-in. Downstream Sample)
Figure 4-44. Barcol Hardness Tester, Taking a
Measurement
Figure 4-45. Barcol Hardness Test Setup
For each specimen a total of 30 readings were taken: 15 on the outer surface and 15 on the inner surface.
Similarly to the durometer (Shore D) hardness test, it was found that the measured inner surface hardness
values were lower than those measured on the outer surface.
The average calculated values and their standard deviations are shown in Figure 4-46. The weighted
average of Barcol hardness for the sample inner surface was calculated to be 16.5 and the weighted error
±1.5, and forthe outer surface 29.3 ±1.3.
59
-------
-ln.
Inner surface (left) Weighted average 16.5± 1.5
Outer surface (right) Weighted average 29.3 ±1.3
Specimen
Figure 4-46. Barcol Hardness of Denver 48-in. Downstream Sample
4.3.10.2 Upstream Sample. Twenty-five hardness readings on the inner and outer side of seven
samples were taken. The average calculated values and their standard deviations are shown in Figure 4-
47. An average of 25 readings at both the inner and outer surface of each of seven specimens is shown.
The weighted average and standard deviation of the Barcol hardness for the sample inner surface was
calculated to be 14.9±1.8 and for the outer surface 18.4 ±2.4.
Denver 48-in. Upstream
D inner surface Weighted average 14.9 ± 1.8
• outer surface Weighted average 1S.4±2.4
SI
S3
S4
Specimen
S5
S6
S7
Figure 4-47. Barcol Hardness of Denver 48-in. Upstream Sample
4.3.11 Raman Spectroscopy
4.3.11.1 Introduction. The general Raman spectroscopy procedures as described for the Denver 8-in.
liner were repeated for each of the Denver 48-in. downstream and upstream samples. Samples of the
resin type used for the original CIPP installations were obtained from the manufacturer for comparison.
60
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4.3.11.2 Downstream Sample. The Raman spectroscopy plots for the Denver 48-in. downstream
sample are shown in Figure 4-48. Four plots are shown for each of the virgin resin, inside liner surface,
and exterior liner surface. The location of peaks is generally the same for the plots for each location with
the exterior surface exhibiting the most variability. A discussion of the possibilities for using Raman
spectroscopy for liner evaluation is given in Section 6.
Denver 48-in. Downstream
Resin 01
Resin 02
Resin 03
Resin 04
nsideOI
n side 02
nside 03
nside 04
Outside 01
Outside 02
Outside 03
Outside 04
700
850
1000
1150
1300
1450
1600
1750
1900
Raman Shift, cm1
Figure 4-48. Raman Spectroscopy Plots (Denver 48-in. Downstream)
4.3.11.3 Upstream Sample. The Raman spectroscopy plots for the Denver 48-in. upstream sample are
shown in Figure 4-49. Four plots are shown for each of the virgin resin, inside liner surface, and exterior
liner surface. The location of peaks is generally the same for the plots for each location with the exterior
surface exhibiting the most variability. A discussion of the possibilities for using Raman spectroscopy for
liner evaluation is given in Section 6.
Denver 48-in. Upstream
850
1000
1150
1300
1450
1600
1750
1900
Raman Shift, cm-1
Figure 4-49. Raman Spectroscopy Plots (Denver 48-in. Upstream)
61
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4.3.12 Comparison of 1995 and 2010 Test Results. Table 4-21 provides a tabulated comparison of
the 1995 and 2010 test results for the Denver 48-in. liner. In comparing the results, it should be known
that the 1995 sample was retrieved only from the upstream side of the manhole (a separate installation
from the downstream with a different liner thickness). A summary of the combined results for all four
sites evaluated is given in Section 6 where the significance of the various results is explored.
The average thickness (14.2 mm) of the TTC-tested upstream sample (taken from the crown area of the
liner) was less than the liner thickness specified for this liner (18 mm). The specific gravity of both the
upstream and downstream liners as measured by TTC according to ASTM D792 (1.07 and 1.08,
respectively) were lower than the results reported in the mercury penetrometer testing (1.16) and lower
than the results reported by Insituform from its testing (1.19).
All of the Denver 48-in. liner samples exceed the specified flexural strength for the liner and all of the
samples, except for one set of tests on the TTC-tested upstream sample, exceed the specified flexural
modulus for the liner. The average flexural modulus value measured for the initial set of coupons from
the TTC-tested upstream sample (182,622 psi) is much lower than any of the other flexural modulus
values reported in this study. The correlation of low values of flexural modulus with other liner
properties such as tensile elongation at break, tensile strength, specific gravity, and porosity is explored in
Section 6. Whether lower than specified values can be attributed to liner aging, to original installation
issues, or to testing variability is also discussed in Section 6.
Table 4-21. Comparison of 1995 and 2010 Test Results for the Denver 48-in. Liner
Property
Sample location
Age, years
Design Thickness,
mm
Thickness, mm
Shore D Hardness
(inner surface)
Shore D Hardness
(outer surface)
Barcol Hardness
(inner surface)
Barcol Hardness
(outer surface)
Specific Gravity
Flexural Strength,
psi
Flexural Modulus
of Elasticity, psi
Tensile Strength,
psi
No. of
Samples
-
-
-
-
18 or 26
each
15 or 25
each
7
1
5
5
3
Test
Standard
-
-
-
-
ASTM
D2240
ASTM
D2583
ASTM D792
Mercury
Penetrometer
ASTM D790
ASTM D790
ASTMD638
Minimum
Specification
-
-
-
-
-
-
-
-
4,500
250,000
-
Insituform
(1995)
MHB3
8
18
18
-
-
1.19
-
6,900
±400
490,000
± 40,000
2,300 ±
170
TTC
(2010)
Upstream
MHB3
23
18
14.2 ±0.2
47 ±2
63 ±3
14.9 ±1.8
18.4 ±2.4
1.08 ±0.03
1.16
5,032±652
6,117±888
182,622±23,126
263,707±70,398
3, 2081222
TTC
(2010)
Downstream
MHB3
23
13.5
13.9 ±0.3
65 ±3
79 ±2
16.5 ±1.5
29.3 ± 1.3
1.07 ±0.04
1.16
7,031 ±346
302,960 ±
24,303
2,995 ± 227
62
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5.0: CITY OF COLUMBUS RETROSPECTIVE STUDY
5.1
Introduction
The initial discussions were held with the City of Columbus, OH in January 2010 about the City's
willingness to participate in the retrospective evaluation pilot studies. The draft protocol outlined in
Section 3 was provided to the City so that they could understand the nature of the program and the
requested role of the City. After the City indicated its interest in participation, a face-to-face meeting was
organized and held in Columbus on February 16, 2010. The City offered two sites for sample retrieval.
The first site was located in the suburb of Clintonville, OH and was offered due to a future project to
upsize the sewer on this street. This site involved retrieval of a 6-ft section of CIPP from a 5-year old, 8-
in. CIPP of a VCP installed in 2005. The second site was a 21-year old, 36-in. CIPP installed in 1989 in a
brick sewer near downtown Columbus at Pearl and Gay Streets. The City of Columbus collaborated on
this project and provided in-kind support for sample collection and on-site support for field testing and
destructive testing (traffic control, utility locating and designation, excavation, and surface restoration at
access points, and CCTV inspection).
5.2
Site 1: 5-year Old CIPP Liner in 8-in. Clay Pipe
This section describes the retrospective evaluation of a CIPP liner installed in Clintonville, OH in 2005.
Although relatively new, the pipe was found suitable for destructive testing because it was already
scheduled for upsizing due to insufficient hydraulic capacity. A short (6-ft) section of the pipe with the
CIPP liner was carefully exhumed and sent to TTC, where comprehensive laboratory testing was
performed.
5.2.1
Host Pipe and Liner Information
Location:
Host pipe:
Burial depth:
Liner dimensions:
Resin:
Primary catalyst:
Secondary catalyst:
Felt:
Seal:
Year liner installed:
Liner vendor:
Resin supplier:
Tube manufacturer:
Richards Road and Foster Street in Clintonville, OH
Circular, 8 in. diameter, VCP, installed in 1924
6 ft (above crown)
8 in. diameter; 6 mm thick
ARPOLMR12018
Perkadox 16
Tert-Butyl Peroxybenzoate Peroxide (TBPB)
Unwoven fabric
Polyethylene coating, 0.015 in. thick
2005
Reynolds Inliner
Ashland
Liner Products of Paoli, IN.
63
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5.2.2 Timeline for Fieldwork
Tuesday, April 13, 2010
7:30 AM Contractor's (Bale) crew began staging equipment and preparing the site for the
excavation.
8:00 AM Excavation began on asphalt roadway. The asphalt layer was approximately 4 in. thick
with 4 in. of road base material compacted beneath. The excavation was carried out
between manholes 0233S0013 and 0233S0010, from 254 ft to 264 ft west of manhole
0233S0013.
After removal of the asphalt pavement, a soil sample was taken at the sub-grade level.
Sample No. 1 was collected and placed in a 1 gallon plastic bag. All samples were
collected with a spade shovel and hand loaded into sample containers.
8:30 AM Excavation was halted and sample No. 2 was collected from the bottom of the trench at a
depth of 3 ft.
9:45 AM In-service, 4 in. diameter, vitrified clay lateral was encountered. The lateral entered the
main line from the south with a 90° bend. At the connection, concrete was poured to assist
in keeping the lateral in place at the main line. No noticeable leaking was detected in this
area. There was also a second, inactive lateral on the north side of the excavation.
10:00 AM Excavation encountered crown of pipe. Excavation was halted and sample No. 3 was
collected from 6 ft below grade and immediately above the crown of the pipe. Sample No.
4 was collected from the side of the trench at elevation 5 ft below grade.
10:05 AM Excavation activity entered the area surrounding and below the pipe. Formation 1 consisted
predominantly of native shale. Visual observation suggested good compaction around the
pipeline. The bedding material was undisturbed with a solid beam support and good
support at the spring lines. Normal condensation was observed around the outside of the
clay host pipe. The clay host pipe was installed with 2 ft joints.
10:55 AM Sample No. 5 was collected with continued hand digging at the spring line level of the
pipe.
11:10 AM Sample No. 6 was collected with continued hand digging at the invert of the pipe.
Bedding beneath the invert consisted mainly of native shale. Traces of excess resin from
the installation were observed and a resin sample collected for future consideration.
11:30 AM Once the line was 90% exposed, shims and bracing were used to support the host pipe.
The pipe was lashed to a wooden support structure and layers of the shrink wrap material
were applied. Two lifting slings were then fitted to the pipe specimen and the excavator. It
should be noted that the host pipe with CIPP was not fully supported several times during
the excavation and removal process, acting as a simple supported beam. One section of
lateral was damaged during excavation and was removed so that the excavation around the
pipe could be completed.
14:00 AM One wastewater sample (Richards-8) was collected for pH and total petroleum
hydrocarbons (TPH) including gasoline range organics (GRO) and diesel range organics
(DRO).
14:05 PM Another wastewater sample (Richards-8D) was collected for pH and TPH GRO/DRO.
14:15 PM The shoring box was set and a temporary line was put in place for the lateral that was
removed. Steel plates were placed over the excavation and cold patch around the edges.
15:15 PM Measurements of the annular gap between the host pipe and liner were taken using a feeler
gauge at both ends of the specimen and at both ends of the remaining pipe before the repair
is made.
15:30 PM The construction crew finished wrapping the specimen and loaded the specimen into the
bed of a truck.
64
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April 16, 2010
The specimen was received at TTC (see Figure 5-1).
Figure 5-1. Images of the Recovered Specimen (Columbus 8-in. Liner)
5.2.3 Visual Inspection of Liner. The visual inspection in the field was documented by Ed
Kampbell of Jason Consultants. The liner appeared to be in good shape overall (see Figure 5-2). The
polymeric film on the CIPP appeared to be intact with no evidence of hydrolysis. In-situ measurements
indicated that the CIPP was at least 6.0 mm thick around the circumference, with the greatest thickness
observed being approximately 6.5 mm. The annular space was very small, including that at the branch
connection. A large amount of resin was formed around the circumference of the liner at each branch
connection location. There was no evidence of external hydrostatic loading (no visible signs of a seasonal
water table). The resin-impregnated felt was solid and intact. The stitch holding together the CIPP tube
was found to be in good condition. Signs of wear were restricted to the bottom third of the tube. The
liner varied significantly in external diameter as it accommodated the short pipe segments between the
four branches.
Figure 5-2. Images of the Inner Surface of the 5-year Old Columbus 8-in. Liner
65
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5.2.4 Locations of Soil Samples. The trench was divided into six regions (Figure 5-3). Soil
samples collected from each region were placed in airtight bags to avoid foreign contamination and/or
loss of moisture. The samples were numbered as shown in Table 5-1.
CD
(3}
Ground
Figure 5-3. Location of Soil Samples
(Columbus 8-in. Site)
Table 5-1. Designation of Collected Soil Samples
(Columbus 8-in. Site)
Soil Sample Location
Subgrade 2 + 63
3 ft below subgrade
5 ft below subgrade
6 ft below subgrade -just above
crown
Bedding along the spring line
On the invert
Sample ID
1
2
o
3
4
5
6
5.2.5 Analysis of Soil Samples. Standard test methods ASTM C136 and ASTM C128 were
followed to classify the soil and determine its particle size distribution. In addition to these tests, the pH
of the soil samples was measured using a pH meter.
5.2.5.1 Particle Size Distribution. The soil gradation analysis followed ASTM C136. Based on
visual inspection, the soil samples were categorized as fine aggregates. Some large particles (e.g.,
asphalt, rocks) (see Figure 5-4) were also present, but were considered a foreign material and were
excluded from the sieve analysis. For the analysis, 500 g of soil material was taken from each of the six
soil samples and placed on a No. 4 sieve (4.76 mm). For all samples (excluding the large foreign
material), 85 to 95% of the particles passed through the No. 4 sieve.
Figure 5-4. Collected In-Situ Soil Samples (Columbus 8-in. Site)
66
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The resulting gradation curves are shown in Figure 5-5.
0)
c
0)
CL
0.01 0.1 1 10
Sieve Opening (mm)
Figure 5-5. Grain Size Distribution of Soil Samples (Columbus 8-in. Liner Site)
Based on the grain size distribution, both the backfill and bedding soils can be considered to be sandy
soils. The flatter slopes of the resulting gradation curves suggest that the bedding and surrounding soil
are well-graded.
5.2.5.2 Soil Specific Gravity and Absorption. This standard testing method is used to calculate the
density, relative density, and absorption of fine aggregates. Soil material weighing 500 g was taken from
each of the six samples for performing the needed tests. The results are listed in Table 5-2.
Table 5-2. Soil Specific Gravity and Absorption Results (Columbus 8-in. Site)
Sample ID
1
2
3
4
5
6
Soil
GO
500
500
500
500
500
500
Bulk Specific
Gravity (OD)*
2.28
1.73
1.57
1.52
1.18
1.56
Bulk Specific
Gravity (SSD)**
2.42
2.07
1.98
1.97
1.59
1.96
Apparent Specific
Gravity
2.65
2.61
2.63
2.78
1.99
2.60
Absorption
(%)
6.04
19.59
25.53
29.77
34.41
25.44
*OD: Oven dry.
** SSD: Saturated surface dry.
67
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5.2.5.3 Soil Moisture Content. ASTM D2216 is a test method used to determine the moisture
content in soils and rocks by mass. Samples weighing 1,000 g from each of the six locations were placed
in an oven for a period of 24 hr. After 24 hr, the soil samples were weighed and returned to the oven for
an additional 24-hr period. The process was repeated until the difference between two subsequent
measured weights was less than 1 g. At this point, the soil was assumed to be moisture free. Moisture
content values for the six soil samples are listed in Table 5-3.
Table 5-3. Soil Moisture Content Results (Columbus 8-in. Site)
Sample ID
1
2
3
4
5
6
Moisture Content (%)
5.65
16.47
19.77
17.34
22.54
23.83
5.2.6 Measurement of Acidity, Alkalinity, and pH. The pH of the soil embedment and the solid
sediments collected from the pipe invert were measured using a Thermo Orion and a sympHony SP70P
pH meter (see Figure 5-6). The soil samples were placed in a pan (which was rinsed using distilled water)
and distilled water was added to the samples. The soil sample was then stirred, and the pH probe was
inserted into the soil-water mixture. The process was repeated for the sediments collected from the
bottom of the liner on the inside of the pipe. The pH values of the bedding soil, backfill soil, and the
sediments are listed in Table 5-4.
Figure 5-6. Measurement of pH (Columbus 8-in. Soil Samples)
The pH of soil samples collected from around the pipe (bedding material) and the backfill soil were found
to be somewhat alkaline ranging from 7.3 to 8.9. The sediments inside the pipe were also found to be
slightly alkaline (with an average pH of 7.6) as expected from a residential wastewater stream. These
measurements do not provide any indication of a severe service environment for the liner.
68
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Table 5-4. Soil pH at Designated Locations and Sewage pH (Columbus 8-in. Site)
Designation
1
2
3
4
5
6
Soil, pH
7.89
8.74
7.92
8.85
7.87
7.30
Sample
1
2
o
J
-
-
-
Sewage, pH
8.01
7.46
7.29
-
-
-
5.2.7 Wastewater Analysis. Retrieved wastewater samples were tested by American Analytical
Laboratories, Inc., on April 14, 2010, in accordance with EPA Test Methods. EPA Method 150.1 was
used to determine pH of samples. EPA Method 8015 was used to determine DRO and GRO to test for the
presence of petroleum hydrocarbons. The results are shown in Table 5-5.
Table 5-5. Results of Wastewater Analysis (Columbus 8-in. Site)
Sample ID
Richards-8
Richards-8D
PH
7.49
7.44
DRO
(mg/L)
1.55
1.81
GRO
(mg/L)
36.8
31.3
Note: Richards-8 and Richards-SD are two samples taken from the same location and tested for QA
purposes.
This data was selected to gauge the chemical characteristics of the wastewater in order to compare it to
the chemical resistance test solution specified under ASTM D5813. Under ASTM D5813, CIPP
materials are subjected to very low pH solutions (1% nitric acid and 5% sulfuric acid) and a petroleum
hydrocarbon fuel. The pH of the wastewater was slightly basic at 7.44 to 7.49. The TPH content (DRO
plus GRO) at 33 to 38 mg/L was within the range expected for normal sewage, which is less than 100
mg/L for total oil and grease (from synthetic sources such as petroleum products and animal/vegetable
sources combined). Under ASTM D5813, CIPP is exposed to 100% Fuel C. The "C" refers to the vapor
pressure and distillation class under ASTM D4814. ASTM Fuel C represents a typical gasoline with high
aromatic content (50% toluene/50% iso-octane).
5.2.8 Annular Gap. The gap between the CIPP liner and the host pipe was measured at 45 degree
increments around the circumference of the liner at both ends of the exhumed sample, as well as exposed
ends of the remaining pipe sections. In the laboratory, nine separate measurements were made at each of
the eight circumferential locations and averaged for the value at that location. The CIPP liner was found
to tightly fit with the inner wall of the host pipe, with the average and standard deviation for the gap being
0.35±0.26 mm. The measurements are summarized in Table 5-6 and Figure 5-7.
69
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Table 5-6. Annular Gap Measurements (Columbus 8-in. Liner)
Location
Crown
45° between crown and right
spring line
Right spring line
Right haunch
Invert
Left haunch
Left spring line
45° between crown and left
spring line
North End of
Specimens
(mm)
0.30
0.16
1.27
0.10
0.12
0.39
0.34
0.37
South End of
Specimens
(mm)
0.39
0.27
0.30
0.49
0.36
0.10
0.30
0.18
North End of
Remaining
Pipe (mm)
0.41
0.23
1.14
0.20
0.18
0.43
0.28
0.41
South End of
Remaining
Pipe (mm)
0.51
0.53
0.33
0.43
0.10
0.13
0.20
0.36
Columbus 8-in.
1.40
1.20
1.00
0.80
0.60
0.40
0.20
0.00
Measured Locations
Figure 5-7. Histogram of Annular Gap Measurements (Columbus 8-in. Liner)
5.2.9 Liner Thickness. A total of 320 readings were taken to measure the liner thickness at
different locations around the pipe circumference. These readings were taken using a micrometer with a
resolution of ±0.0001 in.
The average thickness of the liner at different locations is shown in Figure 5-8. The thickness at the
crown (5.7 mm) was found to be similar in thickness to the other locations (invert and spring line) around
the circumference of the liner. The average liner thickness for each location is slightly less than the as-
specified liner thickness of 6.0 mm. Additional discussion of the data measured at the time of installation
with the current data is given in Section 5.2.14.
70
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Columbus 8-in.
I
6.30
6.20
6.10
6.00
5.90
5.80
Designed Thickness 6.Omm
Weighted average (Crown) 5.72 mm ±0.12 mm . St Dev 0.299
Weighted average (SL- Right) 5.72 mm ± 0.09 mm St Dev 0.255
Weighted average (SL-Left) 5.73 mm ±0.09 mm StDev 0.277
Weighted average (lnvert)5.70mm± 0.10 mm StDev 0.284
Measured Samples
Figure 5-8. Average Thickness at Different Locations (Columbus 8-in. Liner)
5.2.10 Specific Gravity and Porosity. Measurements of density and porosity of a sample from this
liner specimen were made by TTC and by Micrometrics Analytical Services. The TTC result for specific
gravity (based on testing of 7 samples) was 1.11 ± 0.94. In the Micrometrics testing (using mercury
penetration for the porosity determination), the bulk density (at 0.54 psia) was 1.1739 g/mL, the apparent
(skeletal) density was 1.2782 g/mL, and the porosity was 8.163%. The full test report is provided in
Appendix C and the specific gravity results across all samples are compared and discussed in Section 6.
5.2.11 Ovality. A profile plotter (Figure 5-9) developed at TTC was used to obtain a profile of the
interior of the liner to be tested for buckling under external pressure. This profiling system is equipped
with an LVDT rotating a full circle in one and one-half minutes. The voltage reading changes as the tip
of the LVDT moves axially and those readings were collected using an HP 34970A DAQ. Later, the data
was processed to obtain the actual profile of the liner's inside circumference. Before profiling, the pipe
and profile plotter were positioned horizontally (Figure 5-10) and aligned. Figure 5-11 shows the plotted
circumferential profile of the liner.
Figure 5-9. Electronic Level Used to Position Horizontally the Pipe (Left) and the
Profile Plotter (Right)
71
-------
Figure 5-10. Profile Plotting with LVDT Rotating on the Inner Circumference:
Close Up (Left) and Complete View (Right)
Profiling was performed before and after the buckling test. The profile plotter was not used during the
test due to the risk of water leakage and/or sudden failure that might damage the LVDT.
Figure 5-11 compares the pre-buckling and post-buckling profile plots. From the pre-buckling profile
plot, it can be seen that the liner did not follow a perfect circular shape. The liner had several
irregularities that probably matched irregularities in the original host pipe with the largest excursion
(nearly a quarter inch outwards) from a circular shape occurring at the invert of the liner. The ovality of
the liner calculated in accordance with ASTM F1216 was 7.4%. It should be noted that for the buckling
test (described in Section 5.1.15), the liner was inserted and sealed within a circular steel pipe.
Profile Plot
-
7
\
H(
x
y\
i
i
V
\
V
\
st-Pipe(St
/
^
I
^
X
Post-Buckling
!55s,
^
X
^
^^
X
\
^
/
£_
/
\
\
\
I
I
/
/
^
\
1
/
Figure 5-11. Profile Plot of Steel Host Pipe and Liner Before and After the Buckling
Test (Columbus 8-in. Liner)
72
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5.2.12 Flexural Testing. Specimens with a geometry described in ASTM D790 were cut from the
crown, spring line, and invert of the retrieved CIPP liner for measuring the liner's flexural strength and
flexural modulus elasticity. A total of 15 specimens were prepared and tested (five from each location).
The sides of specimens were smoothed using a grinder and a table router. The water jet cutter normally
used for specimen preparation could not be used in this case as the dimensions of the liner cutouts were
too small to hold inside the cutting board. The specimens were marked as shown in Figure 5-12. Testing
was performed using an ADMET eXpart 2611 machine (Figure 5-13). Table 5-7 lists the dimensions and
moment of inertia for each of the 15 specimens.
Using the information in Table 5-7, the following flexural stress and strain graphs for crown samples,
spring line samples, and invert samples were drawn and are shown in Figure 5-14.
Peak load, bending stresses, and deflections were obtained from the calculated data while the software
'MtestW was used to calculate the peak shear stress and bending modulus of elasticity values for the
different specimens. These values are given in Table 5-8.
Figure 5-12. Flexural Test Specimens (ASTM D790): Before Test (Left) and After Test (Right)
Figure 5-13. Flexural Testing in Accordance with ASTM D790
73
-------
Table 5-7. Geometric Data for Flexural Test Specimens for Columbus 8-in. Liner
Location on
Pipe
Crown 1
Crown 2
Crown 3
Crown 4
Crown 5
Spring line 1
Spring line 2
Spring line 3
Spring line 4
Spring line 5
Invert 1
Invert 2
Invert 3
Invert 4
Invert 5
Span
(in.)
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Dimension
W (in.)
0.429
0.5043
0.525
0.4777
0.4337
0.506
0.527
0.5147
0.4933
0.5057
0.4723
0.441
0.462
0.4437
0.4747
D (in.)
0.244
0.2117
0.222
0.2147
0.2067
0.2117
0.2763
0.27
0.219
0.212
0.2177
0.2173
0.2167
0.2197
0.224
Moment of Inertia
(in.4)
0.0005193
0.0003987
0.0004787
0.0003940
0.0003192
0.0004001
0.0009263
0.0008442
0.0004318
0.0004015
0.0004061
0.0003771
0.0003918
0.0003921
0.0004446
Table 5-8. Flexural Test Results for Columbus 8-in. Liner
Location
on Pipe
Crown 1
Crown 2
Crown 3
Crown 4
Crown 5
Average
SL 1
SL2
SL3
SL4
SL5
Average
Invert 1
Invert 2
Invert 3
Invert 4
Invert 5
Average
Overall
average
Peak load
Ob)
23.69
22.41
26.89
23.2
18.5
-
21.63
38.93
36.01
22.18
23.22
-
23.93
21.17
18.78
20.45
23.49
-
-
Peak Bending
Stress
(psi)
9,019
8,815
8,432
5,509
4,218
7,199±2190
7,284
8,224
8,769
3,759
4,074
6,422±2351
6,702
6,575
7,106
4,273
3,478
5,627±1635
6,416±2038
Peak Shear
Stress
(psi)
213
207
247
222
180
214±24
122
251
247
205
217
208±52
220
168
190
199
235
202±26
208±34
Flexural Modulus
(psi)
403,627
388,943
397,758
331,615
310,870
366,563±42,340
311,381
345,226
417,900
266,013
300,069
328,118±57,614
355,290
375,527
403,380
304,084
279,070
343,470±51,125
346,050±49,748
74
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Flexural Stress Vs Flexural Strain
0.01 0.02 0.03 0.04
Flexural Strain, in/in
0.05
0.06
Flexural Stress Vs Flexural Strain
£
i
0.01 0.02 0.03 0.04
Flexural Strain, in/in
0.05
0.06
Flexural Stress Vs Flexural Strain
jj
0.01 0.02 0.03 0.04
Flexural Strain, in/in
0.05
0.06
Figure 5-14. Flexural Stress-Strain Curves for Crown, Spring Line, and Invert Samples
(Columbus 8-in. Liner)
75
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5.2.13 Tensile Testing. Specimens with dimensions consistent with the values provided by ASTM
D638 were cut from the crown, spring line, and invert of the exhumed CIPP liner as shown in Figure 5-
15. A total of 15 specimens were prepared and tested (five from each location).
Figure 5-15. Tensile Specimens for Columbus 8-in. Liner: Before the Test (Left)
and Following the Test (Right)
Using the information given in Table 5-9, the following figures were drawn: Stress-strain curves for
crown samples, spring line samples, and invert samples (Figure 5-16).
Table 5-9. Summary of Results from Tensile Testing for Columbus 8-in. Liner
Location on Pipe
Crown 1
Crown 2
Crown 3
Crown 4
Crown 5
Average
Spring Line 1
Spring Line 2
Spring Line 3
Spring Line 4
Spring Line 5
Average
Invert 1
Invert 2
Invert 3
Invert 4
Invert 5
Average
Overall average
Area
(in.2)
0.1309
0.1462
0.1258
0.1346
0.1338
-
0.1401
0.1720
0.1651
0.1612
0.1753
-
0.1273
0.1318
0.1352
0.1346
0.1318
-
-
Peak Load
0b)
580
545
544
497
525
-
459
644
763
581
567
-
516
474
556
455
563
-
-
Peak Stress
(psi)
4,430
3,730
4,325
3,694
3,920
4,020±340
3,274
3,747
4,619
3,607
3,233
3,696±560
4,051
3,597
4,114
3,383
4,265
3,882±374
3,866±426
Mod. E
(psi)
414,243
341,317
432,060
465,690
369,896
404,641±49,467
327,792
348,035
362,158
328,744
327,516
338,849±15,656
341,223
301,994
353,743
359,622
364,794
344,275±25,215
362,588±43,629
76
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Tensile Modulus of Elasticity
0.02
0.04
0.06
Strain, in/in
0.08
0.1
0.12
Tensile Modulus of Elasticity
0.02
0.04 0.06
Strain, in/in
0.08
0.1
4500
4000
3500
3000
2500
2000
1500
1000
500
0
Tensile Modulus of Elasticity
X
-Invert 1
-Invert 2
Inverts
-Invert 4
-Inverts
0.01 0.02 0.03
0.04 0.05
Strain, in/in
0.06 0.07 0.08 0.09
Figure 5-16. Tensile Stress-Strain Curves for Crown, Spring Line and Invert (Columbus 8-in.)
77
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5.2.14 Comparison of Measured Values and QC Sample/Design Values. Table 5-10 presents the
results for ASTM D790 and ASTM 638 testing of the 8 in. Columbus CIPP liner performed immediately
following the installation (5 years earlier) by DLZ Ohio, Inc. The QA sample showed a finished
thickness of 7.5 mm, compared with an average of 5.72 mm measured in this study and a design value of
6.0 mm. One possible explanation for the difference between the two measurements is that the original
QA sample was taken at the upstream end of a long CIPP run, while the exhumed section came from the
downstream end on a relatively steep slope (approximately 8%), which could result in stretching and
subsequent thinning of the liner. Another potential explanation is that the QA sample is typically
prepared by curing an extension of the liner within the manhole. This does not have the same installation
and curing conditions as within the sewer line itself and such samples are generally expected to have
higher test results than coupons cut from within the sewer.
Table 5-11 presents the results for ASTM D790 and ASTM D638 testing of the exhumed section of the
same liner measured by TTC. The overall flexural strength of the liner (6,416 ± 2,038 psi) was found to
be well above the design value of 4,500 psi, but lower than the value reported by DLZ in 2005 (7,264 ±
500 psi). The modulus of elasticity of the specimens taken from the exhumed liner was found in all cases
to exceed the design value of 250,000 psi by a significant margin (see Table 5-11) with an average
modulus of 346,050 ± 49,748 psi. The flexural strength and the flexural modulus of the specimens taken
from the spring line and invert of the liner were found to be below the respective values at the crown.
The flexural strength of the exhumed liner is 12% below the value reported for the as-installed liner.
Likewise, the flexural modulus of the exhumed liner is 25% below the value reported for the as-installed
liner. These values may be expected to have some differences because the as-installed samples are not
taken from the liner run itself, but rather from an extended portion of the liner within a manhole. The
variation of data across all the retrospective specimens is examined further in Section 6.
Table 5-10. Test Data from 2005 CIPP (as-installed) Sample (Columbus 8-in. Liner)
Property
Flexural Strength
Flexural Modulus of
Elasticity
No. of
Samples
5
5
Test Standard
ASTM D790
ASTMD638
Test Value
Mean +/- Std Dev.
7,264+/- 500 psi
464,652 +/- 30,000 psi
Minimum
Specification
4,500 psi
250,000 psi
Table 5-11. Summary of 2010 Retrospective Data (Columbus 8-in. Liner)
Location
Crown
Spring line
Invert
Overall
average
Property
Flexural strength
Modulus of elasticity
Flexural strength
Modulus of elasticity
Flexural strength
Modulus of elasticity
Flexural strength
Modulus of elasticity
No. of
Samples
5
5
5
5
5
5
15
15
Test Standard
ASTM D790
ASTMD638
ASTM D790
ASTMD638
ASTM D790
ASTMD638
ASTMD790
ASTMD638
Test Value
Mean +/- Std Dev.
7,199 ±2,190
366,563 ± 42,340
6,422 ±2,351
328,118 ±57,614
5,627 ± 1,635
343,470 ±51, 125
6,416 ±2,038
346,050 ± 49,748
78
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5.2.15 Buckling Test. A mechanical steel tube served as the host pipe for the exhumed liner. The
tube was 2 ft long and 9.0 in. inner diameter (ID), to accommodate the ovality and curvature of the liner.
Two 3/8 in. threaded holes were made on the opposite sides of the mechanical tube, and quick connectors
were fixed to the pipe through the holes to allow attaching the pressure system. Two specially designed,
open-ended, conical steel caps (Figure 5-17) were fabricated to keep the annular space between the inner
wall of the pipe and the outer wall of the liner uniform and 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.
Outer
Flange
Polyurea
Inner
Flange
Front View
Liner
Inner
Flange
Figure 5-17. Drawing of the Pressure Cap Used
The liner was centered inside the tube and a special sealant was poured between the host pipe and cap
(Figure 5-18). The caps were pressed against each end of the pipe specimen using three threaded rods
(Figure 5-19).
Figure 5-18. Placement of Liner Inside the
Host Pipe
Figure 5-19. Experimental Setup
A high pressure pump system (Figure 5-20) was used to generate the needed water pressure, which was
applied through a quick connector. A second quick connector was used as an access port for the gauges
utilized for monitoring the pressure in the annulus during the test (Figure 5-21).
79
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Once the setup was completed, the buckling test commenced (Figure 5-22). The liner held a pressure of
over 50 psi (corresponding to around 115 ft depth of immersion in water) for nearly 15 minutes (Figure 5-
23). Leakage of water was observed through the liner material on the inner wall of the CIPP liner. These
leaks suggest the presence of some migration paths though the resin matrix (Figure 5-24) at this elevated
pressure. The cross-sectional profile of the liner before and after buckling is shown in Figure 5-11.
Figure 5-20. High Pressure Pump
Figure 5-21. Pressure Gauges Connected on the
Tube
Figure 5-22. Pressure on the Liner During
Buckling Test
Figure 5-23. Pressure Gauge Showing Pressure
of 40 psi Applied on the Liner
80
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Figure 5-24. Localized Leak on the Liner - Green Spots Due to Green Food Color
5.2.16 Shore D Hardness. The Durometer (Shore D) hardness test (ASTM D2240) is used to
determine the relative hardness of soft materials, such as thermoplastic and thermosetting materials. This
test measures the penetration of a specified indenter into the subject material under predetermined force
and time. Specimens measuring approximately 1 in. x 1 in. were cut from the crown, spring line, and
invert of the retrieved CIPP liner using a band saw. A total of 24 specimens were prepared and tested
(eight from each location).
All tests were performed using the Shore D hardness scale, which utilizes a weight of 10 Ib (4,536 g) and
a tip diameter of 0.1 mm. Tests were conducted on the inner and outer surfaces and a total of 1,440
readings were performed on samples taken from all of the locations. The recorded values are shown in
Figure 5-25. As was noted in the Denver studies, it can be seen that the inner surface readings are
approximately 23% softer (63.3, 62.3, and 62.4) compared with outer surfaces of the liner (79.5, 81.7, and
83.0). However, it is difficult to separate any effects of exposure to the waste stream from differences
due to the presence of the interior surface coating.
5.2.17 Barcol Hardness. Specimens were also subjected to the Barcol hardness test (ASTM
D2583) as described for the Denver samples in Section 4. The results of the Barcol hardness testing for
this liner are shown in Figure 5-26. The values (average of 6.77 forthe inner surface and 13.76 for the
outer surface) are much lower than for the equivalent testing for the Denver samples. For the inner
surface, this may be a result of the different coating material used in recent liners than was used in the
earlier liners retrieved from the Denver sites. Differences of similar magnitude are not seen in the Shore
D hardness values between the Columbus and Denver 8-in. liners. While there is no correlation between
these two hardness measurements methods, Barcol hardness is the more commonly utilized method in the
CIPP industry. The Barcol hardness values forthe 5-year old Columbus 8-in. liner show little difference
between the inner and outer surfaces or between the invert readings and the crown readings. This may be
due to the relatively short exposure of the liner to service conditions.
81
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OJ
c
•o
i5
j=
Q
0!
b
100
90
80
70
60
50
40
30
20
10
0
Columbus 8-in.
Crown
nlnnersurface Weighted average 63.3 ±0.3 St Dev 2.61
• Outer surface Weighted average 83.0 ±1.S St Dev 5.63
HI
c
-o
fe
O
V
b
Columbus 8-in.
Spring Line
Dlnnersurface Weighted average 62.3 ±0.8 StDev 2.61
H Outer surface Weighted average S1.7± 1.8 StDev 5.63
Columbus 8-in.
Invert
Dlnnersurface Weighted average 62.4+2.2 StDev 2.61
• Outer surface Weighted average 79.5 ± 0.9 StDev 5.63
Figure 5-25. Shore D Hardness Readings on Inner and Outer Surfaces
(Columbus 8-in. Liner)
82
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Columbus 8-in.
Crown
n Inner surface (left) Weighted average 7.0± 0.8
• Outer Surface (right) Weighted average 14.3 ± 1.7
25
20
15
10
5
11
12
Col urn bus 8-in.
Spring Line
D Inner surface (left) Weighted average 6.5 ± 0.8
D Outer surface (right) Weighted average 14.011.6
ro
CD
25
20
15
10
5 -
567
Specimen
10
11
12
Columbus 8-in.
Invert
D Inner surface (left) Weighted average 6.S± 0.8
• Outer surface (right) Weighted average 13.0 ±1.7
10 11 12
Figure 5-26. Barcol Hardness Readings on Inner and Outer Surfaces (Columbus 8-in. Liner)
83
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5.2.18 Raman Spectroscopy. The Raman spectroscopy plots for the Columbus 8-in. liner sample
are shown in Figure 5-27. Plots are shown for the virgin resin, and several locations on the inside and
outside liner surfaces. There is one clear difference in the presence of peaks between the base resin
samples and the exhumed specimens, which was not seen in the Denver samples. A discussion of the
possibilities for using Raman spectroscopy for liner evaluation is given in Section 6.
Columbus 8-in.
—Base Sample 1
—Base Sample 2
Base Sample 3
Base Sample 4
—Inside 1
—Inside 2
Inside 3
Inside 4
700
850
1000
1150
1300
1450
1600
1750
1900
Raman Shift, cnr1
Figure 5-27. Raman Spectra for the Columbus 8-in. Liner
5.3
Site 2: 36-in. Brick Sewer
5.3.1 Host Pipe and Liner Information. The CIPP liner sample tested was exhumed from a 36-
in. brick sewer pipe in Columbus, OH, which was installed in 1868 and re lined with a CIPP liner in 1989
under an emergency modification to Project No. 710404.2 carried out by the City of Columbus,
Department of Public Utilities, Division of Sewerage and Drainage. The original contract work involved
227 ft of CIPP lining of an adjacent 24 in. diameter pipeline 14.5 ft deep with 15 mm thick Insitutube.
The emergency modification included the installation of 98 ft of inversion-installed polyester resin lining
in the sewer at Gay Street. The liner thickness was unknown, but it was assumed to be similar to the
adjacent 24 in. project. The CIPP-repaired section lies under a two-way, two lane road; it is a curved
section that extends from the south side of Gay Street and turns north on Pearl Street. The contractor for
the CIPP repair was Insituform East. No material testing was specified in the original contract or in the
emergency modification.
5.3.2 Sample Recovery. On-site personnel were present from the City of Columbus, Battelle,
Jason Consulting, and Reynolds Inliner, Inc. The Reynolds personnel entered the pipeline, cut out a 52
in. x 24 in. rectangular sample (Figure 5-28) and prepared it for shipment. The sample was collected
from approximately 2 ft upstream (south) of the access manhole (MH 0003C0008) at the 1 to 4 o'clock
position approximately 2 in. above the flow line.
84
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5.3.3 Visual Inspection of Liner. Images of the recovered specimen are shown in Figures 5-29
and 5-30. A visual inspection found the CIPP liner to be in good condition. The polymeric film
(polyurethane) was essentially hydrolyzed except for the area where the seam was sealed. This is
expected as the polyurethane was added as a sacrificial layer for confining the resin during the installation
and curing process. The surface when rubbed clean of debris had a "fibrous finish". This also is to be
expected as the polyester fibers that were formerly embedded in the polyurethane are now exposed.
Figure 5-28. Cutting Out the Columbus 36-in. Liner
Sample
Figure 5-29. The Exhumed Sample, 24-
in. x 52-in. (Columbus 36-in. Liner)
Figure 5-30. Images of the Recovered Columbus 36-in. Specimen
The outer surface of extracted sample mirrored the surface of the brick sewer in which it was installed.
After removing the sample, some evidence of resin migration into the mortar joints was noticed. The
CIPP did not appear to be chemically bonded to the sewer wall; in fact, a portion of the sample area had a
compressed "clay-like" material on its surface, which would have prevented any such bonding. The
mechanical bonding, however, was very good. The liner appeared to be positioned tight against the host
pipe up to approximately the 11:00 o'clock position where an annulus began forming. Sounding the top
of the CIPP indicated that this annulus continued around to the 1:00 o'clock position. This could be
possibly attributable to an inadequate amount of head applied during the inversion process or inadequate
cooling of the liner.
85
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5.3.4 Wastewater Analysis. Retrieved wastewater samples were tested by American Analytical
Laboratories, Inc., on April 14, 2010, in accordance with EPA Test Methods. EPA Method 150.1 was
used to determine the pH of the samples. EPA Method 8015 was used to determine the DRO and GRO
concentrations to test for the presence of petroleum hydrocarbons. The results are listed in Table 5-12.
The pH value measured (7.54) is indicative of typical residential sewage. The wastewater analysis
suggests that the wastewater stream has characteristics typical to residential areas, and no abnormal pH
value or hydrocarbon concentrations were measured.
Table 5-12. Results of Wastewater Analysis for Columbus 36-in. Liner
Sample ID
Pearl 36
pH
7.54
DRO
(mg/L)
1.99
GRO
(mg/L)
34.3
5.3.5 Annular Gap. A feeler gauge was used to measure the annular space around the perimeter
where the sample was removed. The liner appeared to be very tight along the sides and bottom of the
sample and a spacing greater than 0.127 mm was measured at only three locations (see Figure 5-31) - all
along the top side of the sample removal area (see note on crown annulus gap in Section 5.3.3). The end
measurements shown in Figure 5-31 were taken at approximately 4 in. from each end of the cutout and
the middle measurement was taken at its center. Since the liner sample was removed from the host pipe,
no laboratory annular space measurements were possible.
1.64mm
0.86mm
0.87mm
5.3.6
Gap determined to be < .127 on sides and bottom. Feeler
Gauge minimum is .127
Figure 5-31. Annular Space Measurements Around the Sample Removal Area
(Columbus 36-in. Liner)
Liner Thickness
5.3.6.1 Ultrasound Testing. An ultrasonic meter (Olympus 37DL Plus) with a 2.25 MHz contact
transducer was utilized in the field in an attempt to measure the thickness of the CIPP liner (Figure 5-32).
However, the ultrasound testing for thickness did not produce any readings (apparently due to the
thickness of this liner). This issue is discussed further in Section 6.
5.3.6.2 Field Measurements. Caliper measurements of the exhumed liner thickness were recorded
around the edges of the extracted sample in the field as shown in Figure 5-33. The liner thickness
measurements taken in the field are shown in Figure 5-34. The average thickness for the sample was
calculated to be 14.2 mm and standard deviation was 1.5 mm. The original design thickness was not
known, but it was assumed to be 15 mm (i.e., the same as the liner used for the adjacent line).
86
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Figure 5-32. Ultrasonic Testing for Measuring Liner Thickness in the Field
15.60mm
15.59mm
13.69mm
13.50mm
15.57mm
SAMPLE
seam
15.57mm
14.55mm
11.45mm 11.61mm 14.53mm
Figure 5-33. Caliper Measurements of Columbus 36-in. Sample
18
16
14
I 12
01
c
10
8
6
4
2
0
Columbus 36-in. - Field Measurements
i • • • •
! n
Designed thickness 15 mm
Average 14.2 mm ± 1.5 mm
123456789 10
Measurement locations
Figure 5-34. Field Measurements of Thickness for Columbus 36-in. Liner
87
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5.3.6.3 Laboratory Measurements. For determining the liner thickness in the laboratory, specimens
cut out from the liner sample for the ASTM tensile and flexural tests were used. Six specimens were used
and five readings were taken for each of the specimens using a micrometer. The average calculated
values and their standard deviations are shown in Figure 5-35. The original design thickness stated in the
figure was not known, but it was assumed to be 15 mm based on the thickness used for the adjacent liner.
The weighted average for the sample thickness measurements was calculated to be 11.9 mm and the
weighted error ±0.3 mm. The laboratory measured values were 16% lower than the field measured
values.
Columbus 36-in. - Laboratory Measurements
c
o
i
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
Designed thickness 15 mm
Weighted average 11.89 mm ± 0.29 mm
I I I I I I
SI S2 S3
Measured specimens
S4
55
S6
Figure 5-35. Laboratory Measurements of Thickness for the Columbus 36-in. Liner
5.3.7 Specific Gravity and Porosity. Seven specimens from the downstream sample were used to
determine the specific gravity of the liner. The average specific gravity for the sample was calculated to
be 1.17 with a standard deviation of 0.06.
Measurements of density and porosity of a sample from this liner specimen were made by Micrometrics
Analytical Services. In their testing (using mercury penetration for the porosity determination), the bulk
density (at 0.54 psia) was 1.0884 g/mL, the apparent (skeletal) density was 1.3233 g/mL, and the porosity
was 17.752%. The full test report is provided in Appendix C and a discussion of the specific gravity
across all the retrospective site samples is provided in Section 6.
5.3.8 Flexural Testing. Specimen cutting and preparation for testing in accordance with ASTM
D790 follows the procedures described for the other liner specimens. Table 5-13 shows the dimensions
and moment of inertia for the specimens.
Using the information in Table 5-13, the flexural stress and strain data for all samples was drawn (Figure
5-36). Peak load, peak shear stress, and flexural modulus values for each specimen, obtained using the
software 'MtestW, are listed in Table 5-14.
-------
Table 5-13. Geometric Data for Flexural Test Specimens for Columbus 36-in. Liner
Sample
ID
1
2
3
4
5
Span
(in.)
4
4
4
4
4
Dimension
W (in.)
0.542
0.527
0.506
0.489
0.486
D (in.)
0.504
0.518
0.518
0.519
0.530
Moment of inertia of
Area
(in.4)
0.005782
0.005262
0.005861
0.005697
0.006030
Table 5-14. Flexural Test Results for Columbus 36-in. Liner
Sample
1
2
3
4
5
Average
Peak load
Ob)
136.59
127.88
124.63
133.84
151.07
-
Peak bending stress
(psi)
5,965
6,004
5,515
6,084
6,626
6,039±396
Peak shear stress
(psi)
500
492
475
527
587
516±43
Flexural
modulus
(psi)
204,315
202,844
169,527
206,182
251,159
206,805±29,065
7000
Flexural Stress Vs Flexural Strain
Sample 1
Sample 2
— SampleS
Sample 4
Samples
0.02
0.1
0.04 0.06 0.08
Flexural Strain, in/in
Figure 5-36. Flexural Stress-Strain Curves (Columbus 8-in. Liner)
0.12
89
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5.3.9 Tensile Testing. Specimen cutting and preparation for testing in accordance with ASTM
D638 followed the procedures described earlier for the other retrospective samples. Table 5-15 provides
the results from tensile testing. Using the information given in Table 5-15, the tensile stress-strain curves
for all samples were developed and are presented in Figure 5-37.
Table 5-15. Tensile Test Results for Columbus 36-in. Liner
Location on Pipe
1
2
3
4
5
Average
Area
(in.2)
0.3001
0.3043
0.3745
0.2808
0.3198
-
Peak Load
Ob)
971.06
948.33
964.13
814.85
946.61
-
Peak Stress
(psi)
3,236
3,116
2,574
2,902
2,960
2,958±251
MocLE
(psi)
324,878
301,645
293,714
375,324
280734
315,259±42,504
3500
Tensile Modulus of Elasticity
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
0.01
0.02
0.05
0.06
0.03 0.04
Strain, in/in
Figure 5-37. Tensile Stress-Strain Curves (Columbus 36-in. Liner)
0.07
5.3.10 Shore D Hardness. A total of six specimens measuring approximately 1 in. x 1 in. were
prepared and tested using the Shore D hardness test. A total of 36 tests were conducted on each sample:
18 tests on the inner surfaces and 18 tests on the outer surfaces. The average calculated values and their
standard deviations are shown in Figure 5-38. The weighted average of Shore D hardness for the sample
inner surface was calculated to be 66±4, and for the outer surface 79±2.
90
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Columbus 36-in.
D Inner surface (left) Weighted average 65.7± 3.6
• Outer surface (right) Weighted average 7S.9± 2.3
c
ro
.c
Q
01
b
.c
to
Figure 5-38. Shore D Hardness of Columbus 36-in. Liner Sample
The liner hardness was found to be medium to high on the Shore D hardness scale. For the Shore D test
on this sample, the inner surface has an average hardness approximately 17% less than the outer liner
surface.
5.3.11 Barcol Hardness. For each of 10 specimens, atotal of 36 readings of Barcol hardness were
taken: 18 on the outer surface and 18 on the inner surface. The average calculated values and their
standard deviations are shown in Figure 5-39. The weighted average of Barcol hardness for the sample
inner surface was calculated to be 18.9±2.2 and for the outer surface 22.3 ±2.0. As for most of the liners
tested, the outer surface hardness is higher than for the inner surface. For the Barcol test on this sample,
the inner surface has an average harness approximately 15% less than the outer surface.
-Jn. Dinner Surface Weighted average of inner surface 18.9 ±2.2
• Outer surface Weighted average of outer surface 22.3 ± 2.0
15
Figure 5-39. Barcol Hardness Readings on Inner and Outer Surfaces (Columbus 36-in. Liner)
91
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5.3.12 Raman Spectroscopy. The Raman spectroscopy plots for the Columbus 36-in. liner sample
are shown in Figure 5-40. Plots are shown for the virgin resin, and several locations on the inside and
outside liner surfaces. There are no clear differences in the shapes of the curves or the presence of peaks
between the base resin samples and the exhumed specimens. This is similar to the results from most of
the retrospective liner samples. A discussion of the possibilities for using Raman spectroscopy for liner
evaluation is given in Section 6.
Columbus 36-in.
S-
~in
Base Resin 01
—Base Resin 02
Base Resin 03
Base Resin 04
—Liner Inside 01
—Liner Inside 02
Liner Inside 03
Liner Inside 04
—Liner Outside 01
Liner Outside 02
Liner Outside 03
Liner Outside 04
700
850
1000
1150
1300
1450
1600
1750
1900
Raman Shift, cm-1
Figure 5-40. Raman Spectroscopy Plots (Columbus 36-in. Liner)
92
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6.0: REVIEW AND COMPARISON ACROSS THE FOUR SITES
6.1 Introduction
This section reviews the series of tests that were carried out on the CIPP liners retrieved from the City of
Denver and City of Columbus and compares the results across all four sites. This comparison allows
observations to be made regarding the relative usefulness of the data in assessing the CIPP liner
condition.
6.2 Summary for City of Denver Evaluations
Two significantly different CIPP liner installations were reviewed as part of this initial retrospective
evaluation effort for the City of Denver. The sites were chosen for the detailed study on the basis of the
age of the respective liners and to minimize the cost and disruption that would be incurred in retrieving
physical samples.
For the 8-in. clay pipe in a residential area, the location was chosen to be able to sample a 25-year old
CIPP liner and also to coincide with an alley pavement slab that needed to be replaced. The condition of
the CIPP liner was found to be excellent with a minimal annular gap and excellent visual condition. The
type of polyurethane inner layer used in early CIPP installations was found to have been hydrolyzed and
eroded away in the invert and spring line areas of the liner but no significant additional erosion of the
resin layer appeared to have occurred. CCTV inspection of the neighboring sewer lines that had been
CIPP-lined during the same original project also revealed an overall excellent condition of the lining after
25 years in service. A modest number of defects were noted in the nearly 5,800 ft of sewer that was
inspected. Most of the defects appeared to relate to poor restoration of lateral services or partial
misalignment of the lateral opening with the lateral itself. Only two local defects were clearly not
connected to lateral connection issues: a local liner bulge and a detachment of the liner from the wall of
the host pipe.
The flexural and tensile test results on the 8-in. liner yielded values higher than the minimum values
required at the time of installation 25 years earlier. In the TTC testing, the average flexural modulus was
335,340±18,186 psi, the average flexural strength 6,756±546 psi, and the average tensile strength
3,029±179 psi. These results are compared in Table 4-9 with similar testing carried out on the 2010
samples by Insituform, installer of the original liner. Some variations in measured values were presented,
but all of the test results were satisfactory.
Although the short-term buckling test on a section of the retrieved liner had to be placed inside a
surrogate host pipe for testing purposes and was shorter than desired to minimize end restraint effects
during the testing, it did provide an excellent result. Despite some obvious distress to the liner at the high
test pressures, the liner resisted 45 psi external pressure without buckling failure despite having a much
larger annular space during the buckling test than existed in the field.
For the 48-in. brick sewer in a more commercial neighborhood, the retrieved samples were also in
excellent condition. Samples had previously been retrieved from this same location in 1995 after 8 years
of service and were tested again in this project after 23 years of service. The comparison was
complicated by the fact that the two samples retrieved in 2010 came from each side of the manhole, in
separate liner installations, whereas the single 1995 sample came only from one side of the manhole.
Table 4-20 presented the comparison of test results for the three samples. The 1995 results show a
flexural strength of 6,900±400 psi and tensile strength of 2,300±170 psi. The tests performed by TTC on
the 2010 specimens reveal differences in the flexural strength (5,032±652, 6,117±888, and 7,031± 346
93
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psi) and tensile strength (2,995±227psi and 3,208±222 psi) but quite acceptable values. The flexural
strength in all three samples was above the ASTM value of 4,500 psi and the tensile strengths measured
in 2010 were higher than those measured in 1995. However, the modulus of elasticity showed a wide
variation among the three samples: 490,000±40,000 psi in 2005, 182,622±23,126 psi and 263,707±70,398
in the two sets of tests for one sample in 2010, and 302,960±24,303 psi from the other 2010 sample. All
except the one set of tests are above the ASTM F1216 specified minimum value of 250,000 psi. Further
discussion and comparisons among the different tested parameters are explored in Section 6.3.5.
For both CIPP liners, surface hardness measurements made on the internal and external surfaces of the
CIPP liner did show some significant differences between the inner surfaces exposed to sewage flow (the
invert and spring line areas) and the inner surface at the crown of the pipe and all the external locations
tested. The differences were more noticeable in the Shore D hardness testing. It is difficult at this point
to separate the effects of the loss of the sealing layer from any changes in the base resin but it is hoped
that such surface hardness testing may represent a useful non-destructive means of assessing material
changes in a CIPP liner. A next step would be to investigate changes in hardness with depth on the inner
surface of CIPP liners of different ages and condition of exposure.
Overall, the liner samples tested from the City of Denver indicated that the liners are holding up well.
One set of tests for one sample provided a low test value for the flexural modulus but the overall
condition of the sample did not indicate that any particular distress was occurring and a repeated set of
tests using different coupons cut from the same sample gave significantly higher results. Further
interpretation of the liner test results across all the retrospective sites follows in Sections 6.3 and 6.4.
6.3 Summary for City of Columbus Evaluations
The City of Columbus also provided a large contrast in rehabilitation projects for evaluation. One site
provided a 5-year old, 8-in. diameter CIPP liner for which a section of liner and host pipe could be
retrieved easily due to existing plans for upsizing the line. The other site provided the opportunity to
sample a 21-year old, 36-in. liner installed in a brick sewer dating from 1868.
The visual evaluations of both liners were excellent. For the older 36-in. liner, the inner coating layer was
mostly hydrolyzed as in the Denver liners of similar age. For the 5-year old, 8-in. liner, the coating layer
of PE was still intact and in good condition. The annular gaps measured were mostly very small but the
36-in. liner was found to have a larger annular gap at the crown although the width of this gap could not
be measured. For both liners, the average liner thickness measured during this study was less than the
design thickness. For the 8-in. liner, the liner thickness was found to vary slightly around the pipe cross-
section.
The porosity of the 5-year old, 8-in. liner was significantly lower than that of the 21-year old, 36-in. liner
and the variations of porosity and density across all sites is discussed in Section 6.4.4. The Raman
spectroscopy data did not show any particular evidence of resin deterioration for the liners. Similar to the
Denver liners, some differences in surface hardness between the inner and outer surface of both liners
were noted, but it is not possible yet to separate out what impact the presence and/or impact of the surface
layer has on this difference.
With regard to the flexural and tensile testing, the 8-in. liner met the original specifications for flexural
strength and modulus, whereas the 36-in. liner met the strength but not the flexural modulus value. The
correlations of liner properties among the various tests are explored in Section 6.3.5. Following similar
test procedures as for the Denver 8-in. liner, the Columbus 8-in. liner also stood up very well in the
buckling test carried out. It carried 50 psi (equivalent to 115 ft head of water) for 15 minutes without
buckling although some leakage through the liner was noted during the test.
94
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Overall, the liners appear to be holding up well despite the shortfall in thickness over the design
thickness. The flexural modulus value for the 36-in. liner after 21 years of service was below the ASTM
F1216 requirement for the original installation, but no visible signs of liner distress were observed.
6.4
Summary of Data and Observations for All Sites
6.4.1 Visual Observations. The observed visual condition of all of the liners retrieved was
excellent. In the older liners, the older type of polyurethane coating (sealing layer) for the felt was eroded
or missing in those areas regularly exposed to sewage flow. For the newer liner with a PE layer, this
coating layer was still intact. The older form of coating was considered a sacrificial layer, but it has now
been replaced by the major felt manufacturers with either a PE layer or a more durable form of
polyurethane layer.
6.4.2 Annular Gap. Annular gap measurements were made with a feeler gauge for the Denver 8-
in. liner, the Columbus 8-in. liner, and the Columbus 36-in. liner. Across all the sites, the annular gaps
measured ranged between less than 0.13 mm and a maximum of 3.31 mm. For the Denver 8-in. liner, the
average gap measurement was 0.9 mm. For the Columbus 8-in. liner, the gap measurements were well
distributed in value and varied from 0.10 mm to 3.31 mm with an average value of 0.35 mm. For the
Columbus 36-in. liner, the readings were mostly less than 0.127 mm, but with a maximum value of 1.64
mm. Sounding of the crown of the liner in situ in the Columbus 36-in. liner indicated that an annular gap
did exist in this liner from around the 11 o'clock position to the 1 o'clock position. In general, the liners
were still effectively tight against the host pipe. There was evidence of good mechanical interlock in the
large diameter liners installed in the brick sewers, but there was no evidence of significant adhesion of the
liner to the host pipe.
6.4.3 Liner Thickness. The liner thickness was measured at a large number of locations for all of
the liners sampled. Measurements were carried out using a caliper, micrometer, and an ultrasonic
thickness tester. The caliper and micrometer measurements are the main measurements discussed in this
section and are provided in Table 6-1. The ultrasonic testing equipment did not work well on the liner
field samples and testing into the cause of this issue is discussed in Appendix B.
Table 6-1. Summary of Thickness Measurements for All Samples
Measurement Set
Denver 8-in.
Denver 48-in. downstream
Denver 48-in. upstream
Columbus 8-in.
Columbus 36-in.
(field measurement)
Columbus 36-in.
(laboratory measurement)
Location
Crown
Spring line
Invert
Crown
Crown
Crown
Spring line
Invert
Upper
haunch
Caliper/
Micrometer
Values (mm)
5.98±0.07
5.93±0.11
5.91±0.09
13.9±0.3
14.2±0.2
5.72±0.12
5.73±0.09
5.70±0.10
14.2±1.5
11.9±0.3
Values
Measured
by Others
-
-
-
-
18
7.5
-
-
Design
Thickness
(mm)
6
13.5
18
6
15*
Original design thickness not known; assumed to be the same as the liner used for the adjacent line.
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For the 8-in. liners, a small difference in thickness (1.2% variation) was measured between the crown and
the invert in Denver and essentially no difference in thickness was measured in Columbus. The higher
liner thicknesses occurred in the crown of the liner. This difference was interpreted to be due in large part
to the loss of the polyurethane sealing layer (0.38 mm original thickness) in the lower portion of the
Denver 8-in. liner, which if present, would have made the invert of the liner thicker than the crown. The
average thickness value for the Denver 8-in. liner matched very closely to the design value even with the
partial loss of the sealing layer. For the Columbus 8-in. sample, the average liner thickness (5.72 mm)
measured during this study was approximately 4.6% less than the design thickness of 6.0 mm, but
significantly less than the QA value of 7.5 mm measured during installation at the other end of the liner.
In this case, since it was a relatively new liner, it had a PE inner layer that was still intact.
For the large diameter liners, the Denver 48-in. downstream sample exceeded the design thickness, but
the Denver 48-in. upstream sample and the Columbus 36-in. sample both had thickness less than the
recorded design value. There were also differences for the Columbus 36-in. liner between the values
measured in the field with a caliper and the values measured later in the laboratory with a micrometer. A
large number of separate readings were taken for each sample (see Sections 4 and 5 for the details).
The fact that 4 out of the 5 liners sampled did not meet the design thickness originally specified points to
the need for good QA/QC procedures in preparations for CIPP lining and in the field procedures. A liner
can become thinner than intended as a result of insufficient fabric thickness, insufficient resin, and
inaccurate calibration of thickness during impregnation, higher than intended pressures during installation
prior to curing, and/or stretching of the fabric at steep downhill sections of the host pipe.
6.4.4 Specific Gravity and Porosity. Table 6-2 compiles the density/specific gravity and porosity
measurements carried out on the retrospective samples at the Micrometrics Laboratory using mercury
vapor penetration for the porosity measurements.
Table 6-2. Compilation of Porosity Test Results (Micrometrics Data)
Location
Denver
Denver
Denver
Columbus
Columbus
CIPP
Identification
8-in.
Downstream
48-in.
Upstream
48-in.
8-in.
36-in.
Resin
Type
Reichhold
33060
Reichhold
33060
Reichhold
33060
ARPOL
MR
12018*
Reichhold
33420
Felt
Unwoven
Unwoven
Unwoven
Unwoven
Unwoven
Exhumed
Year
2009
2010
2010
2010
2010
Installed
Year
1984
1987
1987
2005
1989
Age
Year
25
23
23
5
21
Porosity
(%)
15.9149
11.262
10.1707
8.1629
17.7519
Bulk
Density
at
0.54psia
(g/mL)
1.0731
1.1645
1.1618
1.1739
1.0884
Apparent
Density
(g/mL)
1.2762
1.3123
1.2933
1.2782
1.3233
* Aropol MR 12018 (unsaturated polyester orthophthalic resin), Ashland Chemicals.
In both Denver and Columbus, the older liners have a higher porosity and lower bulk density than the
younger liners. The 8-in. liner and both of the 48-in. liners in Denver used the same resin and felt, but the
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age difference between the liners is quite small (23 years versus 26 years). The Columbus 8-in. liner at
only 5 years old has a significantly lower porosity and higher bulk density than all of the other liners
which are over 20 years old. Such a change in density and porosity could be due to aging of the resin in
the presence of various environmental conditions, but may also result from installation differences.
As shown in Table 6-3, for bulk density/specific gravity values, a variation of 1 to 8% was found between
the TTC measured values and the values that were measured during the mercury penetration porosity
testing. The values obtained during the mercury penetration testing resulted from the intrusion of
mercury vapor under very high vapor pressures. The differences in values obtained by different testing
methods, though relatively small; do point out the difficulty in measuring performance trends over time
that may also result in only small differences in the parameters used to track the deterioration. These
issues will be discussed further in Section 6.5.4.
Table 6-3. Comparison of Density Data
Identification/Measurements/Values
Sample or
Theoretical
Field
Samples
Theoretical
Porosities
Location
Denver
8-in.
Denver
US 48-in.
Denver
DS 48-in.
Columbus
8-in.
Columbus
36-in.
Bulk
Density
M-metrics*
(g/mL)
1.073
1.165
1.162
1.174
1.088
Bulk
Density
TTC**
(g/mL)
1.160
1.098
1.078
1.114
1.073
Deviation
(%)
8.1
5.7
7.2
5.1
1.4
Porosity
(%)
15.915
11.262
10.171
8.163
17.752
0.000
5.000
10.000
15.000
20.000
Theoretical Calculations
With
Talc
Filler
(g/mL)
1.144
1.207
1.222
1.249
1.119
1.360
1.292
1.224
1.157
1.089
With
ATH
Filler
(g/mL)
1.112
1.173
1.187
1.214
1.088
1.321
1.255
1.190
1.124
1.059
With
No
Filler
(g/mL)
1.006
1.060
1.073
1.096
0.985
1.191
1.133
1.075
1.017
0.959
* Internal Micrometrics standard procedure
** As per ASTM D792
It is also worthwhile to compare the measured densities with theoretical calculations of bulk density when
the densities of the component materials are combined in typical proportions. These calculations are also
shown in Table 6-3 using information on proportions and component densities provided by Insituform.
The calculations assume 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). The amount of
filler within the resin is assumed to be 12% by volume. The component densities used in the calculations
are neat resin density 1.16 g/mL, fibers 1.38 g/mL, talc filler 2.80 g/mL, and ATH filler 2.42 g/mL. Both
the Micrometrics and the TTC bulk densities fall within the ranges calculated depending on the type and
extent of any filler used in the actual liners. Close attention to the bulk density of the final CIPP liner
could provide a worthwhile quality control parameter - but only if the constituent materials and
proportions are accurately known.
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6.4.5 Strength and Flexural Modulus. The flexural strength and flexural modulus are the most
often tested structural parameters for a CIPP lining, not least because minimum values are given for only
these two structural parameters in the ASTM F1216 standard. A compilation and comparison of the
available data from this study on these flexural test parameters and tensile test parameters is provided in
Table 6-4.
For flexural strength, no values measured fall below the ASTM minimum of 4,500 psi. The measured
values range from 5,032 psi to 7,264 psi with quite small standard deviations for each set of measured
values. Excluding one of the 2010 Denver 48-in. sample set values of 5,032 psi, the remaining tensile
strength values fall into quite a narrow range of 5,808 psi to 7,264 psi.
Table 6-4. Comparison of Strength, Modulus and Elongation Values for All Liner Samples
Liner
ASTMF1216
min. value
Denver 8-in.
Denver 48-in.
DS
Denver 48-in.
US (Set 1)
Denver 48-in.
US (Set 2)
Denver 48-in.
(Insituform)
Columbus
8-in.
Columbus
8-in. (QA)
Columbus
36-in.
Age
0
25
23
23
8
5
0
21
Location
N/A
Crown
Spring
line
Invert
Crown
Crown
Crown
Crown
Spring
line
Invert
N/A
Upper
haunch
Flexural
Strength
(psi)
4,500
6,454
±228
6,712
±571
7,103
±702
7,031
±346
5,032
±652
6,117
±888
6,900
±400
7,199
±2190
6,422
±2351
5,627
±1635
7,264
±500
6,039
±396
Flexural
Modulus
(psi)
250,000
329,768
±18,429
340,044
±18,381
336,209
±23,759
302,960
±24,303
182,622
±23,126
263,707
±70,398
490,000
±40,000
366,563
±42,340
328,118
±57,614
343,470
±51,125
464,652
±30,000
206,805
±29,065
Tensile
Strength
(psi)
N/A
3,047
±235
2,990
±205
3,051
±167
2,995
±227
3,208
±222
2,300
±170
4,020
±340
3,696
±560
3,882
±374
N/A
2,958
±251
Tensile
Modulus
(psi)
N/A
411,789
±64,990
401,069
±262
422,006
±44,988
382,420
±60,141
426,787
±58,396
N/A
404,641
±49,467
338,849
±15,656
344,275
±25,215
N/A
315,259
±42,504
Tensile
Elongation at
Peak Stress (%)
N/A
1.2-2.5
1.45-1.65
2.25-2.4
1.5-2.5
1.9-2.5
N/A
1.5-2.5
1.75-2.4
1.0-1.5
N/A
1.0-1.2
Tensile
Elongation at
Break (%)a
N/A
2.0-4.5
1.5-3.5
1.5-4.5
2.5-9.0
1.5-5.5
1.5-2.0
1.0-11.0
2.5-9.0
5.0-8.0
N/A
2.5-6.0
Note: (a) Tensile elongation at break is not a standardized test; no claims are made herein regarding the repeatability
of these measurements or their exact engineering meaning. It is a performance indicator which is believed by some
to be linked to the uniformity of the resin saturation within the felt.
For flexural modulus, only two average values fall below the minimum of 250,000 psi given in the ASTM
F1216 standard. These are for the 2010 Denver 48-in. upstream liner sample with an average flexural
modulus of 182,622±23,126 (Set 1) and for the Columbus 36-in. liner sample with an average flexural
modulus of 206,805±29,065. Retesting with five new coupons cut from the Denver 48-in. upstream liner
sample (Set 2) gave higher results that exceeded the ASTM minimum modulus value.
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Looking for correlations to the low modulus value, it can be noted that the flexural strength recorded for
Set 1 of the Denver 48-in. upstream liner was also the lowest value measured. However, the tensile test
data (representing different coupons from the same sample) were at the upper end of the range of the
remaining results. For the Columbus 36-in. liner with the low flexural modulus value (which was
installed as an emergency change order to an existing contract), the flexural strength and tensile strength
were all near the bottom of the range for all the liner samples, but were not the lowest values. However,
the tensile modulus for the Columbus 36-in. liner was the lowest value recorded.
The 1995 sample of the Denver 48-in. liner was measured with an average flexural modulus of 490,000
psi, which was the highest value recorded in the data included in this study. The remaining modulus
values measured in this study (excluding the Denver 48-in. upstream liner and the Columbus 36-in. liner)
range from 263,707 psi to 366,563 psi. An additional flexural modulus value of 464,652 psi was a
recorded value from the QA/QC testing during installation of the Columbus 8-in. liner.
Hence, the two flexural modulus values measured by other laboratories (464,652 and 490,000 psi) are
significantly higher than the TTC measured values (182,622 to 340,044 psi). This introduces the
possibility that some differences in modulus may occur through variations in sample creation,
preparation, testing procedures, and/or interpretation. In particular, for the Columbus 8-in. QA/QC
sample, the sample is usually prepared by curing an extension of the liner within the manhole. This does
not have the same installation and curing conditions as within the sewer line itself and such samples are
generally expected to have higher test results than coupons cut from within the sewer.
For tensile strength, the average values range between 2,300 psi and 4,020 psi. The Columbus 8-in. liner
tended to exhibit high tensile strengths (3,696 psi to 4,020 psi) and the Denver 48-in. liner tested by
Insituform had a low tensile strength of 2,300 psi. The remaining tensile strengths were all grouped in a
close range between 2,990 psi and 3,208 psi. There is no minimum value for tensile strength provided in
the ASTM F1216 standard.
For tensile modulus, the average values range between 315,259 psi and 426,787 psi. There is no
minimum value for tensile modulus provided in the ASTM F1216 standard and it does not appear to be a
commonly recorded test value.
Tensile elongation at break is sometimes used within the industry to help identify issues relating to liner
composition, but it is reported to be an imprecise measure due to the effect of surface irregularities in the
sample on the elongation at break. A high elongation at break may point to a lower degree of resin
saturation in the liner, but good records of liner wet out and examination of specific gravity data are
considered more reliable. For the test results reported in this study, the tensile elongation (strain) at break
ranges from 1% to around 11%. In this study, the high elongations at break were observed for the
Columbus 8-in. liner samples, but this did not appear to correlate well with poor performance in the other
test values. The most common range for tensile elongation at break for the samples tested ranged from
around 1.5% to around 6%.
The flexural and tensile testing results raise issues about the variability of samples within the same liner
and potential variability in test results among different laboratories. However, some level of correlation
between test results is observed for some of the parameters measured. As the research progresses to other
sites, it will be important to find out which of the parameters are the most sensitive to deterioration of the
liner structural condition and performance, as well as which are the most cost-effective and reliable to
measure.
Most of the liner samples met the original specifications for structural performance in flexure. Even the
two samples that were below the originally specified flexural modulus values appeared to be in good
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condition with no signs of structural distress. For one of these samples, retesting five additional coupons
provided results that did meet the ASTM minimum value. It is considered likely that poorer liners will
have more spatial variability in structural parameters and hence the test results may depend on the chance
of where the coupons are taken. Higher quality liners are more likely to have full resin impregnation and
even curing and should provide more consistent test results.
6.4.6 Buckling Tests. Sections of the two 8-in. liners that were recovered together with the host
pipe were removed from the existing clay pipe and installed in a surrogate steel host pipe for external
pressure testing. The 2-ft length that was available for testing was shorter than would be necessary to
avoid end effects that tend to provide higher buckling pressures. However, the annular gap around the
liner in the surrogate pipe was much higher than that in the site condition, which would tend to lower the
buckling resistance. The Denver liner held 40 to 45 psi (equivalent to 96 to 102 ft head of water) for
nearly an hour without buckling. The Columbus liner held 50 psi (equivalent to 115 ft head of water) for
15 minutes without buckling. In both cases, the level of applied external pressure did cause some leakage
through the liner.
The depth (from the surface to the crown of the pipe) of the Denver pipe was 5 ft and the depth of the
Columbus pipe was 6 ft. Thus, the short-term buckling pressures applied to the specimens were 15 to 20
times the maximum water pressure that would be applied if the groundwater table was at the ground
surface.
6.4.7 Surface Hardness Tests. Surface hardness tests were performed following ASTM D2240
(Durometer Shore D) and ASTM D2583 (Barcol hardness) and the results are tabulated in Table 6-5.
Table 6-5. Summary of Hardness Values
Measurement Set
Denver 8-in.
Denver 48-in.
downstream (20 10)
Denver 48-in.
upstream (20 10)
Columbus 8-in.
Columbus 36-in.
Age of
Liner
25
23
23
5
21
Location
Crown
Spring line
Invert
Crown
Crown
Crown
Spring line
Invert
Upper haunch
TTC Shore D Values
Interior
62.8±3.3
58.9±3.0
56.4±2.3
65.2±3.4
46.6±2.3
63.3±0.8
62.3±0.8
62.4±2.2
65.7±3.6
Exterior
77.5±3.1
79.6±1.4
74.3±1.7
78.9±1.6
62.7±3.1
83.0±1.8
81.7±1.8
79.5±0.9
78.9±2.3
TTC Barcol Values
Interior
43.2±1.5
38.5±0.9
38.9±1.3
16.5±1.5
14.9±1.8
7.0±0.8
6.5±0.8
6.8±0.8
18.9±2.2
Exterior
45.9±1.2
39.4±1.2
42.3±0.8
29.3±1.3
18.5±2.4
14.3±1.7
14.0±1.6
13.0±1.7
22.3±2.0
Insituform
Barcol
Values
38±3
-
-
-
-
-
-
-
-
The measurements for the exterior surface of the liner gave significantly higher readings than those for
the inner surface of the liner when using the Shore D hardness test. On the Shore D scale, average inner
surface values ranged from 46.6 to 65.7 and exterior surface values ranged from 62.7 to just over 83. In
the Barcol hardness measurements, the differences in hardness of the inner surface compared to the
exterior surface values varied significantly. In some cases, the values were quite similar and in others the
exterior values were around double the interior values. It is not clear at present how much of these
differences are due to the presence of and/or degradation of the inner surface layer and how much they
may represent deterioration due to exposure to the waste stream.
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A significantly lower range of Shore D hardness values (less than 50) were measured for the inner surface
of the Denver 8-in. liner where the original surface coating had partly or fully degraded and for the
interior of the 2010 Denver 48-in. upstream liner sample - perhaps correlating to the lower flexural
modulus seen for this sample. All of the exterior Shore D hardness values were very close to 80 except
for the 2010 Denver 48-in. upstream sample which measured 62.7 (over 20 percent less). This low
exterior value may also be connected to the low flexural test results.
The surface hardness tests are easy to carry out, could be adapted to provide an in-situ non-destructive test
and may offer promise for being able to track aspects of liner performance such as variability within a
liner or changes of a liner over time. However, it is believed that testing of a wider range of liners using
different surface preparation protocols would be needed to develop the most consistent test results for
field installed liners.
6.4.8 Raman Spectroscopy and Other Polymer Testing. Raman spectroscopy tests were run on
all the liner samples and these results compared to tests conducted on newly prepared samples of the base
resin. With minor differences, the results for the field samples were quite similar to those for the base
resins. These similar results in terms of the shape of the curves and the locations and magnitude of the
peaks suggested that little chemical deterioration of the resin material had occurred. The applicability of
this test to monitoring subtle issues of deterioration depends on scanning many different points on a resin
surface to provide representative results. Thus, the few scans provided for each sample in this project can
only be considered as indicative of a lack of significant changes in the resin properties.
DSC was also used on some samples to explore the potential of the method to track liner deterioration.
No significant difference was noted in the Tg values between the virgin resin material and aged CIPP
samples from the field, suggesting a similar level of curing and little to no measurable material
degradation.
6.5 Current Findings
The specific findings of the current pilot study with reference to the expected service life of CIPP liners
are necessarily limited by the small number of samples and the various possibilities for low physical test
measurements that can be postulated. However, the study does provide an important starting point for a
broader study of the performance of CIPP liners and other pipe rehabilitation technologies. An important
aspect of the pilot study has been to identify where performance issues or questions exist and to suggest
what forms of testing are the most useful, cost-effective, and reliable in tracking liner performance over
time.
6.5.1 Material Degradation. The liners all appeared to be aging well and most of the liners'
physical test properties appeared quite satisfactory after years in service ranging up to 25 years - half the
originally expected service life. One sample out of five had a flexural modulus value that was lower than
the originally specified value. Another had two sets of test results - one that was higher and one lower
than the ASTM specified value. These results, however, cannot be tied directly to deterioration of the
liner over time. In the case of the Denver 48-in. upstream liner, it appears likely that the poor physical
test properties may have resulted from variability within the liner rather than a change over time.
6.5.2 Conformance of Sampled Liners to Original Specifications. The retrospective evaluation
has also pointed to the fact that some aspects of the liners probably did not fully meet the original
specifications at the time of installation. This is most clear in the case of the liner thickness
measurements, but also is suspected in the case of the Denver 48-in. upstream liner in terms of a local
variation in liner properties. For liner thickness, only one of the five samples retrieved had a thickness
higher than the value specified at the time of its installation.
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6.5.3 Prognosis for Remaining Life. At the end of the initial phase of the retrospective testing
program, the inspection of the condition of the retrieved liners and the physical testing results do provide
an expectation that all of the liners sampled would reach their planned 50-year lifetime under similar
continued service conditions. The lower than specified physical properties (principally thickness and
elastic modulus) measured in some samples did not appear to be causing distress to those liners and may
have been present in the liner at the time of installation. None of the service conditions for the liners
examined in the pilot study would be considered at all severe. The water tables appeared to be low for the
excavated liners and the service conditions in terms of pH and chemical exposure were mild. The
expansion of this pilot study to a wider range of service conditions would help answer the broad issues
concerning expected service life of CIPP liners and its potential variability in connection with issues such
as service conditions and QA/QC during installation.
6.5.4 Testing Issues. A variety of test methodologies were tried in this pilot study, ranging from
the basic data for the thickness of the liner, its specific gravity and its annular gap to structural material
properties such as strength, modulus, and surface hardness. It was noted that significant differences
existed in data reported from QA/QC testing at the time of installation and data from tests conducted by
different laboratories. This suggests that more attention needs to be placed on documenting and reducing
the variability of test results derived from sample recovery procedures and in tests from different
laboratories.
The shortfall in thickness measured for most of the liners coupled with the differences in results from
QA/QC samples taken within a manhole points to the urgent need to develop better non-destructive
means of assessing the acceptability of a newly installed CIPP liner and then tracking its deterioration
over time. It was disappointing to find that commercially available ultrasonic thickness gauges did not
work adequately on field CIPP samples even though they gave good results on laboratory prepared
samples of moderate thickness. Appendix B describes the issue encountered with the use of the ultrasonic
thickness probe with the field samples. The inability of commercially available tools to measure the
thickness of large diameter CIPP liners from the inner surface only (an important QA issue because large
diameters are prone to thickness variation around the circumference) is a clear call for the need for the
development of new technologies for accomplishing this task in a cost-effective and reliable manner.
Raman spectroscopy and DSC tests did not produce any evidence of significant material degradation in
the pilot study. This may be due to the fact that little deterioration was seen in the CIPP liners (a good
finding), but the effort to find or use appropriate chemical testing to monitor liner deterioration is
important to continue.
So far, from the variety of tests conducted, the conventional structural testing (especially flexural
modulus) seems to clearly identify liners with suspected poorer quality with surface hardness and specific
gravity also providing interesting insights. The potential non-destructive nature of surface hardness
testing deployed within lined sewers makes this an interesting avenue to explore. Minimally destructive
sampling and testing might also be reasonably acceptable. For instance, a small diameter core of a liner
might be retrieved and used for thickness measurements, specific gravity measurements, chemical
scanning, and some form of structural testing while allowing a simple robotically applied sealing of the
sample location.
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7.0: RECOMMENDED TEST PROTOCOL FOR FUTURE USE
7.1 Overview of Protocol Implications
The experience in working with the cities of Denver and Columbus on the pilot studies in terms of
retrospective evaluation of CIPP liners was very useful. The research team found that there was strong
interest by the city engineers to participate, especially when sample retrieval could be combined with
other activities that the city needed to undertake. In this section, the cost implications of the study for the
utility participants are discussed. The field and laboratory experiences and the usefulness of the test
results in terms of understanding the expected life of CIPP pipe rehabilitation are summarized. This
information is then used to discuss the technical feasibility of a broader national program for the
retrospective evaluation of CIPP liners, as well as similar programs for other rehabilitation technologies.
7.2 Fieldwork Costs
Each of the cities that participated in the pilot program contributed much or all of the costs for the
fieldwork in retrieving either CIPP liner samples alone (from larger diameter pipes) or a full sample of
CIPP liner including the host pipe (in both cases these were from 8-in. diameter pipes). The costs
incurred for the fieldwork are provided below. These costs do not include the planning and coordination
costs for the city engineers and other staff that were involved in the discussions regarding participation in
the study and the set up of the field tests.
Based on the experiences to date, the direct costs to a municipality to retrieve an approximately 6-ft long
sample of 8-in. diameter lined pipe in a relatively low traffic area can be in the range of $10,000 to
$25,000 when combined with other activities at the same site (e.g., sewer line replacement or pavement
replacement at the site). Costs for person entry into a larger diameter sewer and retrieval of a sample of
the liner only were much less expensive in terms of direct cost, amounting to approximately $1,600 to
$3,500 in the pilot studies. These are preliminary estimates since actual costs will vary with many factors
including: cost profile of city and of location within the city (e.g., downtown, suburban, etc.), depth and
diameter of line evaluated, ease of access, and combination of evaluation with other planned work.
7.2.1 City of Denver Costs. The City of Denver was the first city that the research team
approached. In order to explain what was being proposed, a preliminary draft of the expected evaluation
activities and protocol was prepared for use in the discussion with the city engineers (see Section 2).
After exchanging information by phone and e-mail, a one-half day meeting was held in Denver with the
city engineering team (Wayne Querry and Randy Schnicker) after a suitable site for a retrieval of a liner
plus host pipe segment had been identified. The main determinants for site selection for the sample
retrieval were that the CIPP liner should be one of the oldest liners in the City and that the pavement
above the pipe should be in need of replacement (so that it could be paid for by agreement with the City
department responsible for paving). Following the meeting, the City collected the background
information on the proposed site and made arrangements for field work for the 8-in. host pipe and liner
retrieval. Since the sample to be retrieved was in an alley, there were no special costs for traffic control.
The second sample location was chosen because it was an old CIPP liner and because a sample had
previously been removed from the same site for an evaluation in 1995. Dig-up was not considered
feasible for the evaluation because of the cost and disruption in a busy city location and because of the
need for bypassing of the line. Instead, an active local CIPP contractor was identified that would enter the
sewer line to retrieve the liner sample. Because of their interest in the findings, the contractor did the
work at a below-market rate.
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The direct costs for the city preparation activities and the contractor site work for the two retrospective
evaluations in Denver are approximately identified as indicated in Table 7-1.
Table 7-1. Field Work Costs for Sample Retrieval in Denver
Site/Cost Item
Cost for Excavation and Removal of 8-in. Clay
1st Ave. and Monroe Alley
Sewer Pipe at
Cost for Sample Retrieval and Patching for 48 in. brick sewer
Total Cost
Cost
$ 22,800
$ 1,600
$ 24,400
7.2.2 City of Columbus Costs. The discussions with the City of Columbus began with an
expression of interest by the City at the TTC Industry Advisory Board meeting in October 2009. Follow-
up discussions were held by phone and email in the winter 2009-2010 and a planning meeting was held in
Columbus on February 16, 2010. The sites were chosen to select a 36-in. diameter, 21-year old lined pipe
for CIPP sample retrieval only and to retrieve a host pipe plus CIPP liner from a 5-year old, 8-in. sewer
line that was being replaced because the line needed to be upsized. The principal reason for selecting a
relatively newly relined pipe for inclusion was that the city could not absorb the cost of a separate dig-up
and replace just for the retrospective study. The direct costs for the city for the two retrospective
evaluations in Columbus are shown in Table 7-2.
Table 7-2. City of Columbus Costs
Site / Cost Item
Pay item for Richards Rd - Open Cut Open Cut Point
Repair, 8 in. -12 in. Depth <12 ft, up to length <10 ft
Gay St. - Reynolds Miner force account for Gay St.
Total Cost
Cost
$9,680
$3,520
$13,200
7.3
Developing an Extended Program for Retrospective Evaluation
The purpose of this section is to evaluate the mix of retrospective evaluation activities that might be
employed in a broader program.
For individual cities, it is probably unrealistic to expect a large number of excavations to retrieve samples
for evaluation even though checking on the continued performance of relining work is a very worthy goal.
The purpose of the destructive sample retrieval is to build a detailed evaluation of selected liner sites.
These are not likely to be selected at random for cost and accessibility reasons and hence with a small
number of non-random sites within a city. Therefore, the value of the destructive liner sample retrieval is
in the detailed evaluation of liner properties that can be carried out and in the correlation of those
properties with other parameters concerning liner/site characteristics, liner age, etc., together with the
information that can be gained from CCTV inspections and other NDT evaluations.
Many cities are already doing periodic CCTV inspections and also have mechanisms for keeping track of
specific problems that occur in lined and unlined pipe. Thus, significant value can be added by
104
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combining this broadly available information with additional detailed evaluations of selected liners. It
should be noted in this regard that selecting liners with more severe exposure conditions or other
circumstances likely to cause an accelerated deterioration may provide a greater understanding about
deterioration mechanisms, but may not be representative of the deterioration of liners in general use.
To get the best value from retrospective evaluation activities, it is recommended that a dual track be
followed in which aggregated experiential and condition assessment information on lined pipes be
collected from cities that are willing to participate together with continued intensive evaluation of liners
that have seen a variety of service conditions.
Municipalities have shown great interest in having better nationwide information on the experience with
the rehabilitation technologies that they are using or considering. It also appears from the discussions
with municipalities regarding the pilot studies described here that municipalities would be willing to
participate in providing data about their own experiences in return for being able to access the nationally
aggregated information. Some municipalities may have limited resources to assist in the dig up and
retrieval of host pipe samples or even liner coupons (from larger diameter pipes). As mentioned earlier,
being able to combine the sample retrieval with other needed work - either on the sewer, on neighboring
utilities, or on the pavement above the sewer - significantly eases the decision of the municipality to
participate.
7.4 Aggregating National Data on Liner Performance
Since the ultimate goal of carrying out retrospective evaluations is to be able to provide better guidance to
municipalities on the long-term performance of the various rehabilitation technologies available to them,
it is worth looking ahead as to how that data might be collected into a national database.
Table 7-3 provides a summary of an overall structure that could be used for such a database. The agency
or municipality will be the key provider of the information and the agency name, contact information for
the person providing the data, system size, and current extent of rehabilitation should be recorded.
Various agencies would have differences in the types of technologies used and the specifics of those
technology applications. It is suggested that the categorization of the city experiences be able to be as
detailed as the city data would allow, but would also allow information capture at a broader level when
only that level of information was available. For example, Agency A may be able to break down their
experiences with CIPP installations by whether they were hot-water or steam-cured, which type of resin
was used, etc. Agency B may only have retained sufficient records to be able to provide information on
the length of lines rehabilitated with CIPP and their general experiences with CIPP. The database should
be able to focus on or exclude specific variants if desired or to analyze all of the CIPP data in aggregate.
As discussed in Section 7.3, broad interpreted data from agency records, CCTV inspections, and
condition assessment databases needs to be able to be accessed in the database in addition to well
characterized, quantitative data from retrospective liner testing or the use of specific NDT approaches to
liner evaluation.
It is not intended that the database proposed would attempt to include all of the individual CCTV or
condition assessment data that cities are collecting. Rather, the database proposed would contain the
interpreted results from agencies of the performance of rehabilitation technologies plus specific physical
or NDT that addresses liner performance or degradation. The aggregation of all inspection and condition
assessment information would provide additional opportunities for understanding liner performance, but
is an effort that would require a larger level of resources to accomplish.
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Table 7-3. Overall Structure for a National Retrospective Evaluation Database
Utility Information
Agency
Primary Contact
System Type
System Size
Rehabilitation Program
Overview
Technology Used
Name, City, State (Province)
Name, Position, Phone, Email
Wastewater, Storm, Combined, Water (for future retrospectives)
Miles of Mains, Miles of Laterals, Number of Manholes
Miles per Year Rehabilitated, Miles per Year Replaced
Sliplining
CIPP
Close-fit linings
Grout-in-place linings
Spiral-wound linings
Panel linings
Spray/spin-cast linings
Grouting
Other [user specified]
CIPP Experience Overview
CIPP Usage Data
CIPP Technology Type
CIPP Installation Methods
CIPP Curing Methods
Year CIPP First Used; Total CIPP Length Installed, CIPP Miles per
Year
Full length [ft]; Patch repairs [ft]; Lateral lining [ft]; Tees/top hats
[no]
Air inversion [%]; Water inversion [%]; Pull-in and inflate [%]
Ambient [%]; Steam [%]; Hot Water [%]; UV Light [%]
CIPP Retrospective Case Study - Pipe Data Table
Host Pipe Location
Host Pipe Installation Date
Host Pipe Material
Host Pipe Shape
Host Pipe Diameter
Host Pipe Rehab Length
Host Pipe Burial Depth
Water Table Depth
Soil Conditions
Condition Assessment of Host
Pipe
Problem in the Host Pipe
Street Name, City, State
Year
Ductile iron; Cast iron; Steel; Reinforced Concrete Pipe; Prestressed
Concrete Cylinder Pipe; Brick; VCP; PVC; PE, Other
Circle; Egg-Shaped; Box-Shaped; Other [User-Specified]
in.
ft
ft below ground surface
ft below ground surface
Soft Clay; Firm Clay; Stiff Hard Clay; Loose Sand; Medium Sand;
Dense Sand; Cobble/Boulder; Bedrock; Gravel; Other
Infiltration/Exfiltration Testing [Dates/Results]
CCTV [Dates/Results]
Visual [Dates/Results]
NOT Evaluation [Dates/Results]
Coupons [Dates/Results]
Structural Failure, Insufficient Hydraulic Capacity, Inflow &
Infiltration, etc.
CIPP Retrospective Case Study - Technology Background Data Table
CIPP Type
Date Installed
Liner Design Diameter
Liner Design Thickness
Length Rehabilitated
Installation Method
Curing Method
Liner Installer
Tube Manufacturer
Full length; Patch repair; Lateral lining; Tee/top hat
Year
in.
mm
ft
Air inversion; Water inversion; Pull-in and inflate
Ambient; Steam; Hot Water; UV-Light; Electricity
Name, City, State (Province)
Name, City, State (Province)
106
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Table 7-3. Overall Structure for a National Retrospective Evaluation Database (Continued)
CIPP Retrospective Case Study - Technology Background Data Table (Continued)
Tube Material Type
Tube Material Construction
Sealing Layer Type
Sealing Layer Thickness
Resin Supplier
Resin Type
Resin Trade Name
Primary Catalyst
Secondary Catalyst
Polyester; fiberglass; other
Needled; woven; fiber-reinforced
Polyethylene; polyurethane; other
mm
Name, City, State (Province)
Polyester; Vinyl Ester; Epoxy; Other [User Specified]
User-Specified
User-Specified
User-Specified
CIPP Retrospective Case Study - Technology Post-Installation Data Table
Design Spec: Tensile Strength
Design Spec: Flexural Strength
Design Spec: Ovality
Post-Install: Tensile Strength
Post-Install: Flexural Strength
Post-Install: Ovality
Post-Install: Liner Thickness
Defects Noted via Visual
Inspection
QA/QC Inspection of
Rehabilitated Pipe
Other QA/QC Data Collected
psi
psi
%
psi
psi
%
mm
Wrinkling; Buckling; Blisters; Lateral Opening Issues;
Discoloration; Other [User-Specified]
Infiltration/Exfiltration Testing [Dates/Results]
CCTV [Dates/Results]
Visual Assessment [Dates/Results]
NOT Evaluation [Dates/Results]
Coupons [Dates/Results]
User-Specified
CIPP Retrospective Case Study - Technology Retrospective Data Table
Date of Testing
Performance Study Duration
Soil Classification
Soil Specific Gravity
Soil Moisture Content
Soil pH
Annular Gap
Liner Thickness
Liner bulk density
Liner porosity
Retrospective: Tensile Strength
Retrospective: Flexural Strength
Retrospective: Ovality
Hardness
Raman Spectroscopy
Visual Inspection
Year
Years [Date of Testing - Date Installed]
Gravel; Fine Gravel; Coarse Gravel; Sand; Fine Sand; Medium Sand
Coarse Sand; Clay; Silt
Dimensionless
%
Dimensionless
Measure at 8 locations (mm)
Measure at 8 locations (mm)
g/mL
%
psi
psi
%
Shore D Hardness scale; Barcol Hardness scale
User-Specified; Comparison of Aged to Virgin Resin
User-Specified
CIPP Lessons Learned
Construction Problems
Technology Performance
Problems
Adjustments Made
Continued Use of the Technology
User-Specified
User-Specified
User-Specified
Yes/No plus User-Specified Explanation
107
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8.1
8.0: REPORT ON INTERNATIONAL SCAN ACTIVITIES AND FINDINGS
Introduction
An international review was undertaken to better understand 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 to document
any efforts to evaluate and/or monitor the installed quality of their CIPP installations over the long term.
Face-to-face interviews were held with nine wastewater utilities located in the U.K., France, Germany,
Singapore, and Australia as shown in Table 8-1. The interviews were conducted between March and
October 2010. Appendix C contains a detailed interview report for each utility based upon their
experience with the performance of CIPP installations. In addition, the research team collected
information on CIPP use and quality control in Japan and contacted the Centre d'Expertise et de
Recherche en Infrastructures Urbaines (CERIU) in Montreal regarding a retrospective evaluation effort
that was underway for prior rehabilitation efforts in the Montreal region. These are discussed separately
in Sections 8.7 and 8.8.
Table 8-1. Utilities or Organizations Participating in this Review
Utility /Organization
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
Japan Pipe Rehabilitation Quality
Assurance Association
CERIU
Country
U.K.
U.K.
France
France
Germany
Germany
Singapore
Australia
Australia
Japan
Canada
First use of
CIPP
1971
1975
2000
1996
1992
1994
1997
1979
1986
1986
N/A
Total Network
Length (km)
69,600
54,045
325
450
375
660
3,660
6,844
22,000
380,000
N/A
8.2
Rehabilitation Experience
Three of the participants first used CIPP in the 1970s, and may be considered early adopters of the
technology. The first CIPP was installed in London in 1971 for the Greater London Council's
Metropolitan Water Board, now Thames Water Utilities, Ltd. A 70-m (230 ft) length of the Brick Lane
Sewer, a century old brick 1,170 x 850 mm (46 x 33 in.) egg shaped sewer located at Riverside Close,
Hackney, was lined with a 6 mm (0.24 in.) thick liner. Many of the first CIPP contracts in the U.K. were
undertaken for Thames Water and its agent authorities and by 1981 over a hundred successful
installations had been undertaken in the U.K. in sizes from 4 to 108 in. (200 to 2,740 mm). Much of the
early experience with CIPP was in Europe as Insituform, then the only player in the market, expanded its
coverage from the U.K. by licensing the technology to independent contractors. The Public Utilities
Board (PUB) Singapore did not use CIPP until 1994, but since then has been the biggest user among the
participants. Most of the participants also use other rehabilitation methods. Table 8-2 shows the relative
use of different methods at each utility.
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Table 8-2. CIPP and Other Rehabilitation Methods
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwa' sserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
City
London & region
Midlands region
Chartres
SW Paris
Gottingen
Leverkusen
Singapore
Brisbane
Sydney
Total CIPP
Installed (km)
4-500
700
4
30
42
50
900
45
200
Total Other
Rehabilitation
Methods (km)
Not known
<50
0
<5
24
1
180
64
800
The data in this table reflect the different markets in different regions of the world. Europe is dominated
by CIPP, and Singapore has adopted this as its main method too. Australia, by contrast, developed its
own method, spiral winding with PVC and PE and makes substantial use of fold-and-form pipe lining,
and, as a result, CIPP has never been the dominant method there. Nevertheless, CIPP is the most widely
used method of sewer rehabilitation worldwide and has the longest track record of the currently used
methods. It represents approximately 68% of the rehabilitation work undertaken by the participating
utilities.
Current usage of the range of rehabilitation methods is similar to the historical pattern. This is shown in
Table 8-3. The exception is Gottingen, which has switched recently to greater usage of PE-based
methods.
Table 8-3. Current Usage of Rehabilitation Methods
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
CIPP Installed
last year (km)
20
9
0.5
3
1
5
-200
1.7
20
Other Rehabilitation
Methods installed last
year (km)
Not known
Not known
0
1
7
0
-20
4.7
50
The utilities report a clear trend in the quality of CIPP work. 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.
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The French and German utilities interviewed have switched in recent years to almost exclusive use of
UV-cured CIPP methods. These are considered to be better controlled and to benefit from factory
impregnation, which is more readily supervised than site impregnation. Monitoring of the installation is
also considered to be easier and more thorough. They also tend to let term contracts to single contractors
who can meet specific experience criteria, rather than going to open competitive tender for each project.
The UV-cured methods have taken a dominant share of the CIPP market in Germany, which are both the
largest market in Europe and the technology leader.
The U.K. utilities interviewed also place contracts for a five-year Asset Management Period (AMP) with
a single or small number of selected contractors. This is intended to ensure that better quality installation
is achieved.
In Singapore, there has been relatively little usage of UV-cured methods; air inversion and steam curing
appears to dominate. Epoxy resins are also used for all rehabilitation at diameters up to and including 225
mm (9 in.) despite its contractors experiencing difficulties in controlling the mixed resin in a tropical
climate. Thames Water is the other utility that has selectively specified epoxy resin systems, with
polyester resin continuing to be the dominant resin used. Brisbane Water (now Queensland Urban
Utilities) is the only other utility surveyed in a tropical or semi-tropical region, and makes only limited
use of CIPP because of the difficulty of controlling the curing of the resins used.
Experience of using short liners, top hats or similar for connections, and lateral lining is shown in
Table 8-4.
Table 8-4. Usage of Other CIPP Materials
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
Short Liners
Some
Not known
No
Tried, no longer
used
Tried, no longer
used
Tried, no longer
used
No
660km
200km
Top Hats or
Similar
Few
Not known
No
Tried, no longer
used
Tried, no longer
used
Tried, no longer
used
9,000 km
120km
No
Lateral Lining
Little
Not known
No
4 -5km
6km
No
No
330km
No
Many utilities state that they no longer use either short liners or top hats, based on negative experience
with them. Short liners need to adhere to the host pipe and not shrink, so epoxy resins are used.
Nevertheless utilities have experienced problems with the short liners being damaged by high pressure
water jetting.
8.3 Specifications and Design
The use of specifications by the participating utilities is shown in Table 8-5.
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Table 8-5. Rehabilitation Specifications
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-
Bievre
Gottingen Stadtentwa' sserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
Specification
BS13566Part4
Not known. Design to Water Industry Specifications (WIS) 4-34-04
and Water Research Centre (WRc) Sewer Rehabilitation Manual
(SRM)
Own performance specification
None. Design to Association Scientifique et Technique pour 1'Eau et
1'Environnement (ASTEE) method.
Own specification
Own specification
Own specification based on WIS 4-34-04
EN13566Part4
EPS 01 - Small sewers based on AS 2566 and ASTM F1216
EPS 03 - Large sewers based on AS 2566 and ASTM F1216F
EPS 09 - Oviform sewers based on WRc Manual
Among the utilities with their own specifications, there are significant differences in the characteristics
specified for type testing. Table 8-6 shows the type tests specified.
Table 8-6. Type Testing Required in Specifications
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
Characteristics for Type Testing
Per BS EN 13566. 10,000 hour creep, strain corrosion, Thames' own
infiltration test
Not known.
Not known
None. Design verification only
Creep resistance, tensile modulus, bending modulus. Minimum wall
thickness is 6mm irrespective of design requirements
Creep resistance, tensile modulus, bending modulus. Minimum wall
thickness is 5mm irrespective of design requirements
Flexural strength, tensile strength, compressive strength, shear strength,
density, Barcol hardness
ISO 175; Darmstadt Abrasion Test; DIN 19253; Jetting Resistance Test;
EN 1542; EN1055.
Long term flexural modulus -manufacturers' data
Structural design of CIPP liners is most commonly undertaken by the contractor. Thames Water performs
random in-house design checks, as does Sydney Water. Queensland Urban Utilities and PUB Singapore
do some design in house and have some done by the contractors, and Gottingen has all design done by an
independent consulting engineer. All the others have design undertaken by the installing contractor.
8.4
Preparation and Supervision
All of the utilities interviewed agreed that preparation and supervision are critical elements in achieving a
successful installation. Their importance had generally been learned through bad experiences when either
or both had been inadequate. Table 8-7 shows the different approaches to preparation and supervision.
Ill
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Table 8-7. Preparation and Supervision of CIPP Works
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
Preparation
Jetting
Not known
Jetting and root cutting
Jetting and joint sealing
Jetting
Jetting
Jetting and joint sealing
Not known
Jetting, joint sealing, and
rebar trimming
Supervision
Contractor self-certifies to own
method statement
Contractor self-certifies to
specification. Some audit by
Severn Trent Water.
Third party project manager
Contractor self-certifies under own
QA scheme
Third party consulting engineer
Third party consulting engineer
and Leverkusen
PUB supervisor
Contractor self-certifies under own
QA scheme
Sydney Water supervisor
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.
8.5
Verification and Testing
Table 8-8 shows the required frequency of post-installation CCTV surveys, as well as those utilities
utilizing an III test for in-situ performance testing. The performance test is generally an in-situ
watertightness test to look for exfiltration. However, only two utilities appear to have established a clear
pass/fail criterion for this characteristic. Table 8-9 sets out the mechanical characteristics of the
installation that are tested. Most, but not all of the utilities, take samples from the installed liners for
testing to verify that the installation meets the specification requirements.
Table 8-8. Post-Works Inspection and In-Situ Testing
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
CCTV Survey
S
-
S & after 1 year
•/
-
S & after 4 years
S & after 2 and 5 years
•/
S & after 1 year
I/I Test
Own test
-
-
-------
Table 8-9. Process Verification Testing Undertaken
Utility
Thames Water
Severn Trent Water0 )
Agglomeration de Chartres(2)
Agglomeration des Hauts-de-
Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt
Leverkusen(3)
Public Utilities Board
Singapore
Queensland Urban Utilities
Sydney Water
Third party
Laboratory
•/
-
-
S
S
s
s
s
s
Flexural
Strength
•/
-
-
-
-
•/
S
-
•/
Flexural
Modulus
•/
-
-
S
S
-
s
-
-
Tensile
Strength
-
-
-
-
-
-
S
-
•/
Tensile
Modulus
-
-
-
-
^
^
^
^
^
Watertightness
-
-
-
-
-
•/
-
S
-
Hardness'4'
-
-
-
-
-
-
^
-
•/
Thickness
•/
-
-
S
S
S
S
S
S
(1) No information on Severn Trent
(2) Chartres does not undertake process verification, but is considering adding it to the specification.
(3) Leverkusen also has creep resistance measured.
(4) Public Utilities Board Singapore uses Barcol, Sydney Water uses Shore method.
-------
In addition to the process verification and post-works inspections, there is generally a contractual
requirement that the contractor provide a warranty for the works. The term of the warranty varies by
utility, and, in France and Germany, there are legal limits on warranty periods enshrined in national law.
Table 8-10 shows the warranty periods of the utilities interviewed.
Table 8-10. Warranty Periods on Rehabilitation Works
Utility
Thames Water
Severn Trent Water
Agglomeration de Chartres
Agglomeration des Hauts-de-Bievre
Gottingen Stadtentwasserung
Technische Betriebe der Stadt
Leverkusen
Public Utilities Board Singapore
Queensland Urban Utilities
Sydney Water
Warranty Period
Framework contractor does all remediation under his
contract during its term
Framework contractor does all remediation under his
contract during and after its term
1 year (statutory in French law)
1 year (statutory in French law)
4 years (statutory in German VOB contract law)
4 years (statutory in German VOB contract law)
2 years
1 year. Approx. 3% of installation needs remediation
2 years. Approx. 1% of installation needs remediation
8.6
Utilities' Views on Effectiveness of Sewer Rehabilitation
8.6.1 Based on Long-Term Samples. Of the utilities interviewed, four have taken samples for
testing from CIPP installations after a period in service: Thames Water; Gottingen, Public Utilities Board
Singapore; and Queensland Urban Utilities/Brisbane. In addition, Leverkusen has undertaken CCTV
surveys after 10 and 15 years in service and Sydney Water has done so after 12 years of service in one
line.
Thames Water: The original Insituform liner installed in the Brick Lane Sewer was examined in June
1991. Two panels were cut from the sidewall of liner along the spring line of the sewer about 3 ft from an
access manhole. The location was revisited in October 2001 and two sample panels about 1 foot square
were removed from an area of the sidewall about 4 ft into the sewer. In each instance, test pieces were
machined from the test panels and tested in accordance with the relevant testing specifications: BS2782
Part 3 Method 335A:1978 in 1991 and U.K.WIS 4-34-04/BS EN ISO 178 in 2001. The results are
provided in Table 8-11.
Table 8-11. Test Results from First CIPP Installation
Flexural Property
Modulus MPa
Modulus psi
Strength MPa
Strength psi
Sample Mean
20 Year
2900
420,000
46
6,700
30 Year
3300
480,000
43
6,200
Industry Standard
WIS4-34-04
2200
25
ASTM F1216
250,000
4,500
It is anticipated that Insituform Technologies Ltd. will seek the agreement of Thames Water to sample
this unique installation again in 2011.
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Gottingen Stadtentwdsserung: Gottingen has taken samples of CIPP lining after 5 and 10 years in
service, and some after 12 years. Pieces roughly the size of a sheet of letter paper were removed in
sewers 250 to 600 mm (10 to 24 in.) in diameter. A total of 50 samples were tested by the Institute for
Underground Infrastructure (Institut fur Unterirdische Infrastruktur gGmbH [IKT]) for: elastic modulus;
bending stiffness; thickness; and watertightness. No results were made available but, on the basis of the
results, Gottingen considers CIPP to have an effective service life of 50 years.
Public Utilities Board Singapore: They have carried out inspections of historic rehabilitation projects,
typically after about 10 years in service. The findings are shown in Table 8-12.
Table 8-12. Findings from Retrospective Samples of CIPP in Singapore
Location and Date
Installed
Upper Paya Lebar Rd
(1998)
Kim Seng Rd (2000)
Bishan Street 13 ( 1998)
Ubi Ave 1 btw blk
338/339 (1999)
GeylangRd(1999)
Date
Inspected
10/30/2008
08/26/2009
05/29/2009
02/09/2009
05/30/2009
Diameter
225 mm
225 mm
300mm
150mm
300mm
Thickness
NA
NA
NA
NA
NA
Length
15.4m
34.3m
43.5m
64m
37.8m
Data Collected
Good condition (no
defect)
Good condition (no
defect)
Good condition (no
defect)
Bulging liner
Longitudinal wrinkle
NA = not available
Queensland Urban Utilities - Brisbane: An installation from 1985 comprising 1.9 km of 12 mm thick
750 mm and 825 mm diameter lining was inspected in 2002, i.e., after 17 years of service. The inspection
was by CCTV only and no defects were noted. Since then several further inspections by CCTV and man
entry have been undertaken of this same line, and coupons taken. No defects were noted in the
inspection. Coupons have been retrieved from certain pipes when pieces have been dislodged by high
pressure jetting done for cleaning purposes, but have not been tested to establish their properties. This
has raised concerns over jetting for cleaning in CIPP-lined pipes.
8.6.2 Based on CCTV Inspections. Sydney undertook CCTV inspection of approximately 100 m
of 990 x 660 mm ovoid CIPP lining after 15 years of service. No significant defects were noted.
Leverkusen has undertaken CCTV inspections after 10 and 15 years in pipes from 250 to 1,200 mm
diameter and has not identified any specific problems that raise concern over the general performance of
CIPP liners. They also inspect liners as part of routine maintenance of their network. They plan to start
taking coupons and testing them in the future now that they have a larger program of CIPP works.
In general, the findings from these investigations after a period in service indicate that there is no serious
deterioration in performance of the CIPP linings. None of the findings has raised concerns over the
service life, and those defects found are often considered to be installation issues rather than inherent
weaknesses of the products themselves. The only exception to this is QUU's concern over resistance to
jetting. This was also raised in Germany, where jetting is considered to be the reason for the general
failure of short liners.
8.6.3 Based on General Experience. Two of the utilities interviewed, Gottingen and PUB
Singapore, have a policy of trying to achieve a watertight sewerage system. Gottingen is more concerned
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with infiltration, whereas the driver in Singapore is to eliminate exfiltration. Whereas both use CIPP,
they have different views on its application and effectiveness.
Singapore makes extensive use of CIPP, alongside PVC spiral lining and PE fold and form lining. It has
stipulated epoxy-based CIPP for its smaller sewers and for laterals. More than 80% of the lining
undertaken to date is CIPP and this is 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 PUB. As a result, PUB considers CIPP to be a viable, long-lasting
means of achieving a watertight sewerage system.
Gottingen's city council decided in 1990 to make serious investments in the wastewater system with the
aim of achieving a watertight and maintenance-free system by 2035, including the privately-owned
laterals. Gottingen's aim is a watertight system and, after 15 years of using CIPP, and some 15,000
watertightness tests, they consider that it is an excellent long-term repair method but will not provide a
permanent watertight system. This is due to problems of sealing ends at manholes and of sealing the
openings at lateral connections. CIPP can give a watertight pipe but not a watertight system. Gottingen
has switched its strategy to achieve complete system watertightness to aiming for a 100% PE system, with
welded joints throughout. When installing new pipe, only materials approved by the German Technical
and Scientific Association for Gas and Water (Deutscher Verein des Gas- und Wasserfaches e.V. -
Technisch-wissenschaftlicher Verein [DVGW]) for gas use are allowed to be installed. This is the reason
that since 2006, PE rehabilitation technologies have replaced CIPP at Gottingen.
Of the 36 km (22 mi) of CIPP installed in main sewers in Gottingen, 7 km (4.4 mi) has already been
replaced with PE and eventually all but approximately 10 km (6.2 mi) will be replaced. Taking the
DVGW approach means that the system is effectively being redesigned as a pressure-capable system
based on zero infiltration or exfiltration. As stated above, Gottingen now considers CIPP to be an
excellent long-term repair technology with a service life of 50 years and that can make individual pipes
watertight. But it does not meet their requirement of achieving a permanent, watertight network.
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. Thames Water believes that in its geology the use of leaktight
systems is important to minimizing infiltration and accordingly epoxy resin linings may be required for
small diameters prone to leakage. It does not plan to change its policy on the use of CIPP.
The experience of Severn Trent Water has been generally good. They report some problems with liner
stretch, missed connections, and some wrinkling. They have also experienced problems in re-rounding
severely deteriorated pipe prior to lining. As with Thames Water, they do not plan to change their policy
on the use of CIPP.
The Agglomeration de Chartres uses CIPP to reinforce sewers where there is high risk of root penetration.
For structural problems, and even I/I, open cut replacement with ductile iron pipe is preferred. The
condition of lateral connections and frequent displaced pipes means that CIPP is considered ineffective in
combating I/I. CIPP is considered a maintenance activity rather than capital expenditure/asset renewal.
Nevertheless, Chartres expects to increase its usage of CIPP in the coming years, and to increase
rehabilitation at the expense of replacement in order to improve the network within its limited budget.
The Agglomeration des Hauts-de-Bievre considers CIPP to be a reliable method that will remain the main
one used for sewer rehabilitation works. Good planning and pipe preparation are essential and nothing
should be left to chance. Experienced and knowledgeable consultants and contractors are also necessary
for successful installations. They now enter into annual contracts with one contractor only to ensure
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experience and quality, and do not use a competitive tender for each project. While recognizing that they
could save money, they consider the risk of problems due to inexperience and insufficient money to be
too high. 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 represents approximately 2% of the total
length installed to date.
Leverkusen has concerns over the resistance of CIPP to water jetting used for cleaning. Their cleaning
uses water jetting at 20 bar (290 psi) pressure, and they report some damage to liners from cleaning.
Nevertheless they continue to use CIPP. Their view is 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. They believe that the owner needs to take
responsibility for QA/QC and for supervision and monitoring during installation. Even with experienced
and trusted contractors the correct procedures are not always followed. For example, Leverkusen is
considering introducing infrared spectroscopy to its type testing to ensure that the correct resins are used.
This suggests that the level of trust between owner and installer remains low.
In Australia, the situation is different because of the predominance of PE and PVC fold-and-form and
spirally-wound linings. Sydney Water has used such plastic liners for rehabilitation for over 25 years. In
its reticulation sewers, fold-and-form and spirally-wound liners account for the great majority of work
undertaken. 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 PE-based lining systems than
of CIPP. It shares the concerns of the other utilities over jetting for cleaning in CIPP-lined pipes.
Queensland Urban Utilities has addressed this through changing its operational procedures for jetting by
limiting pressure and using specific designs of nozzle. They consider 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. The nature of sub-tropical regions is such that it may not be well suited to work in such
locations. Also the experience, capability, and commitment of the installer are considered paramount.
The combination of an inexperienced client and an inexperienced installer will lead to problems.
8.7 CIPP Use and Testing in Japan
Japan has a land area of 145,883 square miles, extending about 2,000 miles north to south on four main
islands; Honshu, Hokkaido, Shikoku, and Kyushu. Its population of 128 million is 79% urban, living on
just 3% of the land area. The capital and largest city is Tokyo with a population of about 8.5 million
(25% of the nation lives in Greater Tokyo). There are 11 other cities with populations ranging from 1 to
3.6 million. Japan is subject to extensive tropical storms and some 1,500 earthquakes each year with a
significant impact on pipeline performance issues. Climate varies from temperate in the north to
subtropical in the south with implications for H2S attack in concrete sewers.
Through the last three decades, the government has pumped significant amount of money into the
economy by investment in public projects including provision of water and sewerage services, roads, rail,
airports, and other urban infrastructure. However, in difficult economic times, the government has
embarked on restructuring programs and has begun to cut back on investment in infrastructure projects.
In 2001, the government announced a cut in expenditure of $10.3 billion, targeting areas such as social
security, public works, defense, and education. The impact fell heavily on the construction sector where a
3 to 6% cut in public works has been experienced each year since 2001.
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The water and sewer utilities are managed on a municipality basis, i.e., the local town or city government
takes responsibility for the sewers and water mains. It has recourse to the prefecture and to the central
government to obtain funds to supplement locally raised revenue for capital expenditure, but it funds
maintenance work from its own budgets. With the economy at a low ebb, tax revenues which fund this
expenditure are stressed, and this is in part responsible for the downturn in pipeline construction and
maintenance.
The development of a piped sewer system in Japan commenced in the latter half of the 19th century -
prompted by major cholera outbreaks in Nagasaki and Yokohama in 1877. Piped sewers were
constructed in the foreigners' settlements in Yokohama and Kobe. Tokyo Metropolitan Government
began public sewer construction in 1884. Thereafter, other major cities began sewer construction, but the
pace of development lagged somewhat behind Europe and the United States. Sewerage was generally
managed with an efficient system of collection and transportation of night soil for disposal as agricultural
fertilizer. The system collapsed during World War II due to fuel shortages caused by the Allied blockade
of shipping. The development of a modern sewerage system was a priority in post-war recovery and
sewer construction became an important source of employment for unskilled labor.
However, network growth was slow and sewerage services were only available to 7% of the population in
1963, until it was accelerated by a series of Five Year Plans for Sewerage Construction. Thereafter, a
network of public sewers was rapidly developed to collect and deliver sewage to treatment facilities.
Sewer pipe construction peaked at 68,000 km per annum in 1986. As of 2007, 72% of the population had
connected to the public sewer system and construction continues at about 10,000 km per annum. The
traditional night soil collection system was progressively abandoned, but is still practiced for about 25
million people living in small towns and in country districts. In those communities with fewer than
50,000 population, the connection rate to a public sewer is still only about 29%. Over time, the night soil
collectors have evolved into small local sewer construction and maintenance contractors and some have
entered the growing rehabilitation business to exploit their important connections with local government.
The Japanese sewer network currently comprises about 380,000 km of pipeline. It is funded by a
combination of local and central government support in equal measure at a cost of about ¥ 2,392 billion
(U.S. $29.17 billion) per annum. The Tokyo Metropolitan budget is ¥ 120 billion (U.S. $1.46 billion) to
provide for repair, rehabilitation, and new construction of its 15,000 km network and treatment facilities.
At the present time, this work involves rehabilitation of about 80 km of sewer per annum.
In common with many countries, the life of a sewer pipe in Japan is designated as 50 years. However, in
contrast to other countries where the actual life is often substantially longer, the life cycle of pipes
installed in Japan is often compromised by a combination of aggressive corrosion and frequent
earthquakes. Whilst European and U.S. cities benefit from a legacy of soundly built 19th century
underground infrastructure, much of Japan's sewer network was built in a post-war boom by day labor
using basic pipe products. Much of the network is reinforced concrete pipeline constructed until the mid
1980s from plain ended (Type A) centrifugally spun concrete pipe with cement mortar joints.
According to the Japan Sewerage Works Agency (JSWA), sewer pipe reconstruction commenced around
1946 and continued through the 1970s by open cut methods at a rate of 15 to 40 km per annum. From
about 1975, the rate of replacement increased steadily from 40 to 90 km per annum. The Agency has
analyzed the age of pipe at reconstruction finding two peaks of activity, 10 to 20 and 50 to 60 years after
installation. The Agency has concluded that the first major peak (at 10 to 20 years) is associated with
construction faults and that the latter peak is associated with aging of the fabric of the pipe. JSWA
estimates that 6,000 km of the network is more than 50 years old and 50,000 km is over 30 years old. For
these reasons, Japan experiences an unusually high and increasing level of sewer collapse. In 2005, there
were 6,600 collapses (see Figure 8-1). Thirty-year-old pipes are exhibiting about 40 collapses per 1,000
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km of pipe and 50-year-old pipes are collapsing at the rate of about 130 collapses per annum per 1,000
km of pipe (see Figure 8-2).
8,000
8 6,000
CL
JD
^ 4,000
o
-------
Condition assessment using CCTV was established in the 13 major cities in 1988, examining 1 to 2% of
the pipe stock per annum. The condition is assessed in accordance with the Ministry of Land,
Infrastructure and Construction (MLIT) Manual for Construction and Repair of Sewerage Facilities.
The manual prescribes a formal assessment system based on points assigned to defects which is outlined
in Tables 8-13 and 8-14, providing a means of ranking the urgency of rehabilitation. In analyzing various
sewer lengths, the total points score per span gives rise to a ranking from C to AAA, which determines
the action to be taken. Recommended action may require point repair or rehabilitation of the full span. It
is usual to rehabilitate the whole span in the event of more than four defects in a single span. Short length
rehabilitation or repair may be considered for one to four defects per span.
Table 8-13. JSWA Condition Assessment Method
Type
1
1
1
1
1
2
2
2
3
3
Symptom
Corrosion
Pipe Broken
Joint Displacement
Root intrusion
Mortar Adhesion
Cracks
Protruding laterals
Infiltration
Settlement
Displaced Seals
Fat
Sediment
Severity
Exposed Rebar
Fracture Collapse
Withdrawn offset
40% block
>33%dia.
> 5mm
50%ofdia.
Running
75% dia.
> 50% Circ
>33%dia
20xDepth ratio
Pts
20
20
18
20
20
15
15
12
10
4
20
Severity
Exposed Aggregate
Thru-wall crack
Partial withdrawal
10-40% block
10-33% dia
2-5mm
25-50% dia.
Trickling
50-75% dia.
> 25%Circ
10-33% dia
Pts
15
16
15
10
15
10
5
2
8
o
J
15
Severity
Other
Corrosion
Other
breakage
Joint gap
<10% block
< 10%
<2mm
<25% dia.
Soaking
<50%
<25% Circ
<10% dia
Pts
8
10
3
5
8
5
1
1
5
2
8
rype 1 - seriously affects pipe function, Type 2 - affects pipe function, Type 3 - slightly affects pipe function.
Table 8-14. JSWA Ranking System
Rank
AAA
AA
A
BBB
BB
B
CCC
CC
C
Points per span
70+
40-69
20-39
15-19
10-14
5-9
3-4
2
0-1
Priority
Extremely Urgent
Urgent
Urgent
Repair needed
Repair needed
Repair needed
No action required
No action required
No action required
Rehabilitation methods are classified as standalone, two layered, or complex pipe. The standalone pipe
(similar to the ASTM fully deteriorated category) presumes no residual strength in the existing pipe and
the liner is designed for soil, hydrostatic, and traffic loads. The two layered structure contemplates a
degree of support from the existing pipe (similar to the ASTM partially deteriorated category) and the
liner is designed to support the hydrostatic load only. The complex pipe is that in which the liner is
integrated into the fabric of the pipe (similar to the Water Research Centre [WRc] Type 1). The design
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methods are detailed in the Guide to Pipeline Rehabilitation developed by the Japan Institute of
Wastewater Technology (JIWET), published by JSWA in English and Japanese in June 2001. The guide
has just been revised and expanded by JIWET to include site management and quality assurance
measures. It was published in Japanese only by JSWA in June 2007.
In the period 1988-2006, renovation by repair using resin injection and rehabilitation using hose lining,
fold-and-form, and spiral pipe renewal (SPR) methods grew rapidly (see Figure 8-3). Sewer maintenance
is funded solely from local government funds. Network rehabilitation has been growing steadily since
1986 and is currently undertaken at a rate of almost 500 km per annum. Information obtained from the
Japan Pipe Rehabilitation Quality Assurance Association (JPRQAA) is indicated below for the period
1986 to 2009. Almost 4,800 km of sewer have been renovated by inversion (1,994 km), pull-in-and-
inflate (2,051 km), and spiral wound methods (745 km). The figures for the pull-in-and-inflate method
include both UV and steam cured CIPP and fold-and-form methods (ExPipe and Omega Pipe).
Annual Rehabilitation Construction Record 1 986-2009 (m)
V
o
u
m
600,000
500,000 -
400,000 -
300,000
200,000
100,000
111111111111112222222222
999999999999990000000000
888899999999990000000000
678901 2345678901 23456789
Year
Figure 8-3. Annual Rehabilitation Construction 1986-2009
CIPP was introduced into Japan by Insituform under license to line H2S corroded sewers under the New
Tokyo International Airport in 1986. Hose lining systems, Paltem and Phoenix developed in Japan for
gas pipe rehabilitation were applied to sewer rehabilitation in 1988 and spiral wound pipe was imported
from Australia and adopted by Sekisui in 1989. The Omega fold-and-form system developed by Sekisui
was launched in 2009 and the InPipe UV light curing CIPP was adopted in 1991. The annual
rehabilitation volume grew rapidly from 50 km/year in 1991 to 200 km/year in 1999. In the early years,
the preferred method was CIPP installed by inversion but, by 2005, installation by pull-in-and-inflate
methods (both CIPP and fold-and-form) took 50% of the market and these are now being used for 60% of
rehabilitation works. Currently, spiral wound pipe takes 20% of the market with 60% of that volume in
diameters over 800 mm. In 2009, the methods used were broken down by method and diameter as shown
in Figure 8-4.
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2009 Installations
categorised by method
Spiral
Wound
98.4km
, 20.0°'
Other
0.2km
0%
Inversion
108.2km,
22.0%
Pull in &
Inflate
285.8km,
58.0%
2009 Installations
categorised by diameter
>800mm
63.4km,
12.9%
301-800m
m,
136.0km,
27.6%
< 300mm,
293.2km,
59.5%
Figure 8-4. Installations Categorized by Method and Diameter for 2009
The rehabilitation systems available in Japan are licensed to contractors by domestic and international
system developers. Groups of licensees, installers, and companies in the materials supply chain for given
systems are usually organized together as rehabilitation system associations. Such associations in Japan
may have as many as 500 members and contractors may belong to a number of associations depending on
the systems they offer. The associations provide a platform for technical and commercial activity for the
members who may be relatively small local companies providing sewer maintenance capability to their
municipalities.
The JIWET was established by the Ministry of Construction in 1992 to undertake the research and
development for new sewer construction and rehabilitation technologies and sewage treatment. It has had
a particularly important role in evaluating and certifying technologies in the rehabilitation field. JIWET
provides teams of engineers to undertake the investigative work and organizes committees for evaluation
of new construction and rehabilitation under the chairmanship of leading academics. Activity has grown
substantially. In 2009, JIWET certified or renewed 52 new or improved technologies, including eight for
pipe and manhole rehabilitation and three for pipe repair methods. Products and processes are re-
evaluated and certified after five years, subject to performance in use.
The JPRQAA was launched in August 2006 and represents the interest of the system providers and
associations in connection with a variety of government agencies to have rehabilitation recognized as
equivalent to replacement. The organization collects data on the activities of the system associations and
is a technical resource for monitoring industry quality and performance
The Japan Sewer Collection Maintenance Association (JASCOMA) was set up in 1987 as an organization
of 467 firms and 24 associations involved in sewer cleaning, assessment, and rehabilitation. It has
provided examination and certification for technicians involved in pipe maintenance since 1998 and, in
2003, it set up a scheme to inspect and certify contractors.
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The business of pipeline rehabilitation in Japan is rigorously organized by these and other organizations
such as the Japan Sewage Works Association, which regulates the design process and works closely with
the Japan Industrial Standards Organization. Japan currently provides the Chairman and Secretariat for
the International Standards Organization Technical Committees and Working Groups in the field of water
and wastewater pipe rehabilitation. At a site level, CCTV examination, measurement and sampling, and
testing are required on all installations in accordance with JSWA 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. In the case
of Osaka City, they require all installers to conduct a QC test of each span of the project. However,
conduct of the testing is not limited to authorized laboratories and a test by the supplier is acceptable. In
other cities, such as Tokyo, the independent laboratory is utilized, but one sample from each project is
sufficient.
8.8 Approach to Retrospective Evaluation in Quebec
As a complement to the international scan information collected and described above, the research team
also contacted the Centre de Recherche des Infrastructures Urbains (CERIU) in Montreal, Canada
(www.ceriu.qc.ca) to gather information about a retrospective evaluation study that was underway in the
Province of Quebec. This summary has been prepared on the basis of discussions with Isabel Tardiff,
Technologies Director at CERIU on January 5, 2010. The purpose of the discussions was to establish the
type of retrospective evaluation that was underway in Quebec, how far it had progressed, and to share
information on the types of evaluation procedures that were being used in Quebec and in the EPA study.
The Quebec study is looking at the entire spectrum of rehabilitation efforts in the province including
water main rehabilitation (which has been active since 2001) and sewer main rehabilitation (which has
been active for significantly longer). The purpose of the study is to see how the prior rehabilitation work
is holding up now and to see if the information will allow the rate of degradation to be assessed. The
project is being managed through the municipal entities in the Province with CERIU as a consultant to the
study. A study group involving the interested cities, CERIU, and others was formed, but does not involve
many small cities since they are not much involved in rehabilitation efforts yet. Target cities for the
retrospective evaluation effort were identified. The management of the project has a "Director"
committee composed only of municipal members plus two other committees covering potable water and
sewers/manholes. Contractors and consultants are not involved in the Director committee, but are
involved as appropriate on the other committees. The universities of Concordia (sewer rehabilitation) and
Ecole Polytechnique (water) are supporting the study.
The City of Montreal has been doing water rehabilitation since 2001. In total, 10 municipalities were
named for the study and key participants and volunteers had been identified at the time of the conference
call. It had been important to orient everyone as to the goals and scope of the study and to clarify the
types of deliverables anticipated. Risks affecting the outcome of the study were considered to include:
non-participation by cities and inadequate administrative support or manpower to collect and analyze the
required data. Senior city administrators were called if necessary to bolster support for the study and a
communication plan was prepared - laying out when data would be released, etc. Budget aspects of the
study were further explored to establish the practical extent of in-service testing and the costs of specific
tests that might be used. Milestones for the project were established and the specific team members that
would do the analyses had been identified. The Directors committee was active in encouraging the
participating municipalities to contribute in-kind help to the data collection and study efforts.
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The benefits of the Quebec study were seen to be that rumors about rehabilitation performance can be
addressed and that information critical to life cycle analysis of rehabilitation efforts could be collected.
A strategic decision was made in the study to cover as much of the rehabilitation work as possible so that
the general condition of rehabilitated lines and any visible defects could be identified. This led to the
broad use of CCTV for the assessment work. Specific samples were to be collected for quantitative
analysis based on a review of the CCTV data and the available budget. A survey was sent out to the
municipal participants to establish how many meters of rehabilitation had been accomplished in each
municipality. The survey was also sent to contractors with the promise to keep the data as confidential as
possible.
On the water rehabilitation side, the collection of data on rehabilitated lines had been relatively simple
since there were only two contractors doing the water rehabilitation work. On the sewer side, the
situation was more complex. The contractors had changed over time and there was a need to provide
even representation in the study.
Some cities had already conducted a 10-year evaluation of their own rehabilitation program, e.g., Quebec
City for CIPP relining. CERIU had conducted a review of 12 techniques for manhole rehabilitation in
1999 and had followed up with further evaluation in 2004 and 2009. The evaluation techniques used
were visual inspection plus hammer tapping to identify liner defects. The results of the inspection were
good and a report was to be released soon.
The universities participating in the current retrospective evaluation were focused on physical sampling
for CIPP and pull-in-place liners, etc., but the budget was very limited. The committees for the project
were making decisions about what should take precedence: inspection, sampling, or testing.
Many cities have done prior CCTV inspection. Montreal has 20-year old grouting rehabilitation of
manholes and mainlines that was recently been reinspected by CCTV in October 2009.
Physical samples for sewer lines were planned to be retrieved principally from person-accessible
locations (adjacent to manholes, person-entry diameter pipes, etc.). Concordia University was to do the
testing and analysis. Both destructive and NDT methods were to be used. Some of the test parameters
were to include: Manning's coefficient, liner/sample dimensions, ease of repair, permeability at
connections, flow, and pressure. Most municipalities have before and after CCTV scans for the
rehabilitation. Some municipalities have follow-up CCTV one and five years later.
Some of the municipalities involved in the Province study have mostly done grouting work and some
mostly CIPP. Two pipe groups were anticipated for sample retrieval for water mains: 6 in. diameter and
less and greater than 6 in. diameter. One meter long samples were expected in a full pipe sample
retrieval. Studies of grouting effectiveness were planned to be done by internal pressure testing. Where
the section would not pass, excavation was planned to see if a grout ball exists outside the pipe at this
location.
Testing specifics anticipated were:
• Evidence of water leakage
• General state
• Hazen-Williams coefficient data (static and dynamic testing)
• Water connection integrity
• Pressure and flow data
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• Destructive testing (but will not carry out toxicity testing)
• Thickness of liner
• Internal pressure testing
• Verification of resin penetration at connections
• Three-point bending tests to rupture
• Live loading assessment
• Peel resistance for coatings
• Conformance of liner fracture to pipe fracture
In summary, the Province of Quebec is undertaking a broad retrospective evaluation of rehabilitation
technologies used for sewer collection pipes, manholes, and water distribution pipes with activities that
are very complementary to the work described in this report.
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9.0: SUMMARY AND RECOMMENDATIONS
9.1 Summary
9.1.1 Tasks to Date. This retrospective evaluation pilot study grew out of discussions among the
research team during the early stages of the overall project, Rehabilitation of Wastewater Collection and
Water Distribution Systems, which was to perform a comprehensive review and evaluation of existing
and emerging rehabilitation/ repair technologies for wastewater collection and water distribution systems
and to conduct demonstrations of innovative sewer and water rehabilitation technologies. The need for
such information was reinforced by the participants at an international technology forum held as part of
the project activities in September 2008.
The initial effort in terms of retrospective evaluation was planned as a pilot study. It targeted CIPP
installations only, concentrated on quantitative testing of the CIPP liners, and used samples from both
large and small diameter sewers in two cities, Denver and Columbus. For the small diameter (8 in.)
sewers in each city, a 6-ft section of pipe and liner was exhumed from a convenient site. For the larger
diameter sewers (36 to 48 in. diameter), CIPP liner samples were cut out from the interior of the pipe and
the liner patched in-situ.
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 was gathered as appropriate to
each retrieval process including: external soil conditions and pH, and internal waste stream pH. The
findings from the testing conducted so far are summarized in the following subsections.
As a companion to the pilot studies in Denver and Columbus, an international scan was made of the
approaches used by sewer agencies overseas to oversee their CIPP rehabilitation activities and to track the
subsequent performance of installed liners. A variety of approaches are used - more in the area of
QA/QC at the time of installation than a planned program of follow up to track deterioration of
rehabilitation technologies over time.
Given the insights provided by the pilot studies in Denver and Columbus and the international scan,
recommendations are made for an expansion of the retrospective evaluation study to create a broader
national database that would help to define the expected life of sewer rehabilitation technologies.
9.1.2 CIPP Liner Condition Findings to Date. All of the samples retrieved from the four
locations (five individual liners) involved in the pilot study testing were in excellent condition after being
in use for 25 years, 23 years, 21 years, and 5 years. Four of these liners had already been in service for
approximately half of their originally expected service life of 50 years. Two sets of coupons out of six
sets from five sites had a flexural modulus value that was lower than the originally specified value, but
this cannot be tied directly to deterioration of the liner over time. In the case of the Denver 48-in.
upstream liner, in particular, it appears likely that the poor physical test properties may have resulted from
variability within the liner rather than a change over time since the second set of coupons tested produced
much higher test values. Some indication of a softening of the interior surface of the liner that 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 much of the 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 present on the inside surface of the CIPP liner. For newer CIPP liners, a different
handling/inner layer is used with greater durability.
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In Denver, in CCTV inspections of nearly 5,800 ft of CIPP liners installed at the same time as the
retrieved sample, a few specific defects were noted at different locations. Most of these appeared to relate
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 is no reason to anticipate that the liners evaluated in this pilot study will not last for their
intended lifetime of 50 years and perhaps well beyond.
9.1.3 Initial Findings on Value of Various Physical Testing Approaches. The testing carried
out on the CIPP liners and the data collected about the site and environment in which they were used was
intended to try to capture any evidence of liner deterioration and possible reasons for such deterioration.
The potential value of each type of testing to broader retrospective evaluation studies is briefly identified
below.
9.1.3.1 Soil Conditions. Soil testing, including soil type, gradation, density, moisture content, pH,
etc., would only be available during a dig-up of a pipe or liner sample. The data could help to identify if
the host pipe had uniform soil support or was developing external voids due to leakage into the pipe. The
data also can provide a background on external conditions that may relate to corrosion/deterioration of the
liner and/or the host pipe. For example, for steel, cast iron, and ductile iron pipes, a number of tests (e.g.,
soil resistivity, pH, redox potential, presence of sulphates and chlorides, etc.) have been proposed for
determining the expected rate of external corrosion of uncoated pipelines. The data is not difficult to
collect when an excavation is made and provides a basis to answer questions about external pipe
conditions if such questions arise. Soil samples taken during excavation, but not tested unless needed
could also provide important backup for later testing as needed, but moisture content and pH at a
minimum should be determined when soil sampling is conducted.
9.1.3.2 Visual Inspection. A thorough visual inspection is important to provide the overall
appearance of the liner and any evidence of surface changes such as the deterioration or loss of the
internal sealing layer, evidence of leakage (e.g., discoloration), or porosity. As with any visual condition
assessment using a standard protocol for recording the findings is important to create useful results in a
broad database.
9.1.3.3 Thickness and Annular Gap. The thickness of the liner is a critical parameter for the
resistance of the liner against a variety of potential failure modes. In particular, it indicates (in
conjunction with other physical liner properties) whether the liner currently meets the requirements of
ASTM F1216 in terms of its resistance to external buckling. Annular gap measurements provide
information about potential shrinkage or displacement of the liner away from the host pipe. A significant
annular gap may allow longitudinal movement of the liner in the pipe and increase the possibility of liner
buckling under external pressure. A significant annular gap also increases the potential for water
migration between the host pipe and the liner. If lateral connections and/or liner terminations at manholes
are not sealed, then infiltration into the sewer system can occur.
Annular gap can be measured easily and effectively with feeler gauges. Thickness can be measured using
calipers within the area of a sample or a ruler at the edge of the sample. Ultrasonic measurements can
also be made when only one side of the sample is available and are potentially very useful both for
retrospective evaluations and for QA/QC of new installations. In this pilot study, poor success was
experienced with the ultrasonic measurements. They correlated with physical measurements on
laboratory-prepared thinner liner samples, but did not return useful results on the field-installed or thicker
liners. The problem is thought to be related to the dissipation of the acoustic signal in the resin-fiber
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composite. More research on identifying or developing a better NDT method or equipment for in-situ
liner thickness measurement is recommended.
9.1.3.4 Flexural and Tensile Testing. The testing of flexural specimens for the structural
performance represented by the flexural strength and flexural modulus is often carried out since it can be
compared with the specified values in the ASTM F1216 standard. Tensile strength and tensile elongation
at break also have been measured values when structural liner performance is investigated. In this study,
other parameters such as the tensile modulus were also recorded. From the testing conducted so far, the
flexural modulus tests provided the most useful values for interpretation but, of course, that may not be
the case for all types of liner issues. The tensile elongation at break varied over a wide range in the tests
conducted. Typically, when flexural and tensile testing is carried out, all the parameters mentioned above
are easily measured and recorded and could prove useful in a larger data set for establishing correlations
among types of liner defects and the test values for each parameter.
9.1.3.5 Surface Hardness Testing. Surface hardness testing was found to reveal differences between
the hardness of the inner surface of a CIPP liner and its external surface and to reflect the low flexural
modulus value and the variability of the tensile elongation at break value of the Denver 48-in. upstream
liner sample. While few conclusions can be drawn from the surface hardness data collected to date, this
type of testing appears to hold promise for evaluation of liner properties - either as-installed or their
degradation over time. As a non-destructive test that could potentially be deployed in pipelines of 8-in.
diameter (and larger), such a test could provide a quantitative non-destructive measure of great value and
it is recommended that further investigations of data correlations and test adaptations to in-pipe
measurements should be pursued.
9.1.3.6 Material Composition Testing. It is considered very important in the assessment of liner
deterioration to find a test or set of tests that will shed light on chemical or physical changes occurring in
the liner material over time. Tracking the rate of such deterioration (in conjunction with other liner and
site characteristics) would provide important information in projecting the lifetime of a liner. In the pilot
study, no evidence of liner deterioration was seen in the Raman spectroscopy and differential DSC testing
that was carried out. This is either due to the lack of deterioration in the samples tested compared to the
virgin resins tested or because the test is not sensitive to any type of deterioration that may, in fact, be
occurring. It is recommended that these tests and/or similar forms of material testing be applied to
deliberately aged liner specimens to establish the signatures of particular forms of deterioration before
they be applied in a wider context for tracking liner performance in the field.
9.1.4 Recommendations for National Data Compilation and Management. The ultimate goal
of carrying out retrospective evaluations is to be able to provide better guidance to municipalities on the
long-term performance of the various rehabilitation technologies available to them. Table 7-3 provided a
summary of an overall structure that could be used for a database to accommodate the differences in the
types of technologies used and the specifics of those technology applications. It is suggested that the
categorization of the city experiences be able to be as detailed as the city data would allow, but would
also allow information capture at a broader level when only that level of information was available. As
discussed in Section 7.3, broad interpreted data from agency records, CCTV inspections, and condition
assessment databases need to be accessed in addition to well characterized, quantitative data from
retrospective liner testing or the use of specific NDT approaches to liner evaluation. However, it is not
intended that the database would attempt to include all of the individual CCTV or condition assessment
data that cities are collecting. Rather, the database proposed would contain the interpreted results from
agencies of the performance of rehabilitation technologies plus specific physical or NDT that addresses
liner performance or degradation.
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9.2 Recommendations for Future Work
9.2.1 Recommendations for Continued Retrospective Evaluations on Retrieved Samples. The
expected life of rehabilitated sewers is critical to the effective asset management of sewer systems and yet
very little quantitative study has been made to determine the performance and/or degradation of
rehabilitation technologies with time. This pilot project examined five CIPP liners at four sites in two
cities. The results are very promising for a life of CIPP liners that will meet or exceed the 50 years which
has been taken as the nominal life expectancy for such liners. The results, however, cannot be taken as
representative of the tens of thousands of miles of rehabilitated sewers that have already been installed
using many variations of CIPP and other rehabilitation technologies. It is 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 survey to capture the locally interpreted data from a wide range of cities 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.
• Additional research on root cause analysis of CIPP failures.
9.2.2 Recommendations for Development and Calibration of NOT Protocols. The alternative
to obtaining large physical samples for quantitative testing is to use NDT to obtain meaningful data,
which was also recommended by the utilities participating in this study, and/or to test small physical
samples that are easily retrieved robotically from inside the pipe and easily repaired. This project has
tested several quantitative liner characterization tests that could be expected to be developed for robotic
deployment within sewer mainlines of 8-in. diameter and larger. It is recommended that additional
research be carried out to develop and characterize the most promising NDT protocols.
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APPENDIX A
LIST OF TEST STANDARDS REFERENCED
-------
The following table lists ASTM standards that are referenced in this report.
Standard
ASTM C 128
ASTMC136
ASTM D638
ASTM D790
ASTM D792
ASTMD2216
ASTM D2240
ASTMD2583
ASTMD5813
ASTM E96
ASTM E797
ASTME1356
ASTM E2602
ASTMF1216
ASTM F 1743
ASTMF2019
ASTM F2599
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 Test Method for Tensile Properties of Plastics
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 Methods for Laboratory Determination of Water (Moisture)
Content of Soil and Rock by Mass
Standard Test Method for Rubber Property — Durometer Hardness
Standard Test Method for Indentation Hardness of Rigid Plastics by Means of
a Barcol Impressor
Standard Specification for Cured-in-Place Thermosetting Resin Sewer Piping
Systems
Standard Test Methods for Water Vapor Transmission of Materials
Standard Practice for Measuring Thickness by Manual Ultrasonic Pulse-Echo
Contact Method
Standard Test Method for Assignment of the Glass Transition Temperatures
by Differential Scanning Calorimetry
Standard Test Method for the Assignment of the Glass Transition
Temperature by Modulated Temperature Differential Scanning Calorimetry
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 (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
A-l
-------
The following table lists the non-ASTM standards, guidelines, and manual of practice listed in this report.
Contact information is provided for the organization.
ASTEE - Association Scientifique et Technique pour 1'Eau et
1 ' Environnement
Council of the Standards Association of Australia
• AS2566 Plastics Pipelaying Design
British Standards Institute
• BS 2782-10 Methods of testing plastics. Glass reinforced plastics.
Measurement of hardness by means of a Barcol impressor.
• BS EN 1055: 1996 Plastics piping systems. Thermoplastics piping
systems for soil and waste discharge inside buildings. Test method
for resistance to elevated temperature cycling.
• BS EN 1542: 1999 Products and systems for the protection and
repair of concrete structures. Test methods. Measurement of bond
strength by pull-off
• BS EN 13566-4:2002 Plastics piping systems for renovation of
underground non-pressure drainage and sewerage networks.
Darmstad Rocker Test Method (abrasion)
• See DIN 19565
DIN (Deutsches Institut fur Normung e.V.)
• DIN 19565 (PI) Centrifugally cast and filled polyester resin glass
fibre reinforced (up-gf) pipes and fittings for buried drains and
sewers.
EN Standards (CEN - European Committee for Standardization)
• BS EN 1055: 1996 Plastics piping systems. Thermoplastics piping
systems for soil and waste discharge inside buildings. Test method
for resistance to elevated temperature cycling.
• BS EN 1542: 1999 Products and systems for the protection and
repair of concrete structures. Test methods. Measurement of bond
strength by pull-off
• BS EN 13566-4:2002 Plastics piping systems for renovation of
underground non-pressure drainage and sewerage networks. Lining
with cured-in-place pipes
ISO (International Standards Organization)
• ISO 175: 1999 Plastics ~ Methods of test for the determination of
the effects of immersion in liquid chemicals
• ISO 178:2010 Plastics ~ Determination of flexural properties
WIS (Water Industry Standard)
• WIS 4-34-04 Specification for renovation of gravity sewers by
lining with cured-in-place pipes.
WRc (Water Research Center UK)
• WRc SRM (Sewer Rehabilitation Manual)
www.astee.org/
www. standards .org .au/
www . standardsuk. com/shop/
www.normas.com/DIN/pages/
Translations .html
or
http : //global . ihs . com/
www.standardsdirect.org/
standards/
www.iso.org/
www.water.org.uk/
www.wrcplc.co.uk/
A-2
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APPENDIX B
INVESTIGATION OF ULTRASONIC MEASUREMENTS FOR CIPP THICKNESS
-------
B.I Introduction
This study was conducted using an ultrasonic thickness gauge probe (Olympus 37DL utilizing a 5.0 MHz
transducer). The research team was unable to obtain any reading when attempting to obtain thickness
measurements on the five CIPP liners recovered during the retrospective study (from both Columbus and
Denver). In order to determine the cause for this inability of the equipment to perform as expected, the
TTC undertook a study utilizing homogenous materials and CIPP liners with a range of resin types and
resin saturation levels. A list of the materials used in the evaluation program of the Olympus 37DL is
given in Table B-l. The results of this study are discussed here for future consideration of the utility of
ultrasonic measurements in similar field studies.
Table B-l. List of the Material Used for Measuring Thickness
Material
CIPP made with Quik POX resin
CIPP made with Quik PE resin
CIPP made with Reichhold resin
CIPP sample
(Marked as Ultra Sonic 1)
CIPP Sample
(Marked as Ultra Sonic 2)
CIPP Sample
(Marked as Ultra Sonic 3)
PVC Pipe SDR 3 5
Polyurea/polyurethane hybrid
CIPP felt
Steel
Sound Velocity
(in./jusec)
0.1043
0.1043
0.1043
0.05-0.15
0.101
0.101
0.0945
0.001-0.15
0.2643
Remarks
Approximately 6.5 mm (0.25-in.) thick control
specimens with a known range of resin content
(0.5, 1.0., 1.5, 2.0, and 2.5, Ib/l.f. for a 7.5-in.
dia. liner)
Approx. 6.5mm (0.25-in.) liner; this sample
was not properly impregnated. The instrument
was ineligible to read thickness for a sound
velocity ranging from 0.05 to 0. 15 in. / //sec.
Approx. 6.5 mm (0.25-in.) thick, well
impregnated and cured CIPP sample
Approx. 6.5 mm (0.25-in.) thick, well
impregnated and cured CIPP sample
N/A
3.5 mm (0.14-in.) coupon; the instrument was
unable to provide a reading for sound velocity
ranging from 0.05 to 0. 15 in. / //sec.
No readings
N/A
Note: N/A = not available
B.2 Preparation of Controlled Specimens
The TTC developed control specimens using three different resin types and five resin concentrations
(specified as Ib of resin per linear foot of 7.5-in. diameter felt). These samples were prepared in a
controlled lab setting. A 6-in. x 6-in. felt panel was impregnated with resin using a roller system and
cured in the microprocessor controlled oven as shown in Figure B-l. The resins used for preparing the
samples were QuikPOX, Quik PE and Reichhold. Following the curing process the 6-in. square panels
were cut to prepare 1-in. x 1-in. specimens, as shown in Figure B-2. The thickness of each specimen was
B-l
-------
measured using a slide caliper. Next, the ultrasonic device (Olympus 37DL fitted with a 5.0 MHz
transducer) was used to measure the thickness of each specimen, as shown in Figure B-3.
Figure B-l. CIPP Roller System (left), Oven (middle), and a Batch of Controlled Specimen after
Curing (right)
M m u b
a-o 3-5% ^ ,.0
a • • • •
1-0 1'5
Quik POX Quik PE Reichhold
Figure B-2. Three Different Types of Resin Used for CIPP Saturation
Figure B-3. Measuring with Slide Calipers (left) and Olympus 37DL (right)
B-2
-------
Mean thickness values for each control specimen are shown in Table B-2. From the data, it can be seen
that the ultrasonic gauge works well when the specimen is well impregnated in resin (2.0 Ib/ft or higher
resin content), but does not provide a reading when the resin content falls to 1.5 Ib/ft.
Table B-2: Measured Thickness of the Controlled Specimens
Resin
Content
Ib/ft
2.50
2.00
1.50
QuikPOX
Slide
Calipers
(in.)
0.234
0.242
0.217
Ultrasonic
(in.)
0.234
0.241
N/A
QuikPE
Slide
Calipers
(in.)
0.269
0.240
0.239
Ultrasonic
(in.)
0.268
0.237
N/A
Reichhold
Slide
Calipers
(in.)
0.228
0.201
0.196
Ultrasonic
(in.)
0.229
0.198
N/A
N/A = Reading not available
B.3 Other Specimens
The ultrasonic gauge did not provide readings when used on a felt sample. This is attributed to the
absorption of acoustic energy by the material. The device also did not provide a reading when used on an
improperly cured liner, as shown in Figure B-4.
Figure B-4. Ultrasonic Thickness Measurements on Improperly Cured Liner
The device worked well in the case of a PVC liner. A SDR35 PVC pipe was used. When measured with
a slide calipers, average thickness value was 0.187". Using the ultrasonic device, the thickness found was
0.182-in. to 0.183-in., as shown in Figure B-5.
Figure B-5. Ultrasonic Instrument Used to Measure Thickness of PVC Pipe
B-3
-------
When utilized for measuring the thickness of a 6.5 mm, well-impregnated and cured CIPP liner, the
discrepancy between thickness values measured using slide calipers and the ultrasonic probe were on the
order of 1% (see Figure B-6).
Figure B-6. Ultrasonic Instrument Used to Measure Well Cured Liner - MTC (left) and Insituform
(right)
A summary of the measured average thicknesses for all sample specimens is given in Table B-3.
Table B-3. Comparison of Thickness Measured using the Slide Calipers and the Ultrasonic
Device
Sample Specimens
Improperly cured CIPP liner
(Ultra Sonic 1)
Properly cured CIPP liner
(Ultra Sonic 2)
Properly cured CIPP liner
(Ultra Sonic 3)
Properly cured CIPP Liner
Ultra Sonic 4)
PVC Pipe SDR 35
Polyurea/polyurethane hybrid
White Felt
Steel
Measured Thickness
Slide Calipers
(in.)
0.203
0.280
0.270
0.268
0.187
0.127
0.112
0.187
Ultrasonic Device
(in.)
N.A.
0.281
0.271
0.267
0.183
N/A
N/A
0.188
Remarks
Improperly impregnated
sample
None.
None.
None.
None.
None.
None.
None.
N/A = Reading not available
B.4 References
01. http://www.bamr.co.za/velocity%20of%20materials.shtml
02. Olympus 37DL - Manual
B-4
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APPENDIX C
INTERNATIONAL STUDY INTERVIEW REPORTS
-------
INTERNATIONAL STUDY INTERVIEW REPORTS
The interview reports from international utilities are provided in this appendix including: Thames Water
(TW), Severn Trent Water (STW), Communaute d'Agglomeration de Chartres (CAC), Communaute
d'Agglomeration Les Hauts-de-Bievre (CAHB), Gottingen Stadtentwasserung (GS), Technische Betriebe
der Stadt Leverkusen (TBL), Public Utilities Board (PUB) Singapore, Brisbane Water (BW), and Sydney
Water (SW).
C.I Thames Water (TW)
In 1973, the U.K. Department of the Environment established 10 regional water authorities including
Thames Water Authority (TWA) to manage water resources and the supply of water and sewerage
services on a fully integrated basis. Prior to this reorganization, there were more than 1,000 bodies
involved in the supply of water and around 1,400 bodies responsible for sewerage and sewage disposal.
In 1989, under the terms of the Water Act, these authorities were privatized as water and wastewater
service companies and TWA became Thames Water Utilities, Ltd., the largest water and wastewater
service company in the U.K. Within the southeast region of the U.K., there are also a number of small
water service only providers.
TW has an extraordinary heritage including the construction of the New River in 1613, an artificial water
course built by Sir Hugh Myddleton that brings fresh water from the River Lee and Amwell Springs to
the City of London. TW also inherited the vast interceptor sewers commissioned by Prime Minister
Disraeli's government in the 1860s and built by Sir Joseph Bazalgette to restore the Thames River. TW
was acquired in 2001 by RWE, a German Utility Company and is presently owned by Kemble Water,
Ltd., a consortium owned by Macquarie Group, Ltd., an Australian investment bank.
TW employs 5,000 staff and spends U.S. $1.5 billion a year to maintain its water and sewer network,
which includes over 20,000 miles of water mains (about 30% of which is over 150 years old), 100 water
treatment plants, 288 pumping stations, 265 reservoirs, 43,500 miles (70,000 km) of sewer, 800,000
manholes, 2,530 pumping stations and 349 sewage treatment plants (STPs) including Beckton, Europe's
largest sewage treatment plant. It is the utility responsible for water supply, wastewater collection, and
treatment in parts of Greater London, Surrey, Gloucestershire, Wiltshire, Kent and the Thames Valley in
the U.K. Each day, it supplies 686 million gallons of tap water to 8.5 million customers across London
and the Thames Valley and collects and treats 740 million gallons of sewage for an area of South England
covering 13.6 million customers. Standards of service are set for TW by three regulatory bodies
responsible to the Department of the Environment, Food and Rural Affairs (DEFRA). These are the
Office of Water Services (OFWAT) responsible for service quality and efficiency; the Environment
Agency (EA) responsible for rivers and other water sources, pollution and flooding; and the Drinking
Water Inspectorate (DWI) responsible for drinking water quality.
TW has for many years been at the center of the development and usage of techniques for sewer
rehabilitation. The first CIPP was installed in the Brick Lane Sewer, a century old brick, egg-shaped
sewer located at Riverside Close, Hackney in 1971 and many of the first CIPP contracts in the U.K. were
undertaken for TW and its agent authorities. TW Manager, Graham Cox, made the case for trenchless
rehabilitation at the Institution of Civil Engineers Conference 'Restoration of Sewerage Systems' held in
London in 1981, emphasizing that inversion lining was established as a well tried and proven method of
making full use of the cross-sectional area of the existing pipe. Cox identified that by 1981 over a
hundred successful installations had been undertaken in the U.K. in sizes from 4 to 108 in. (100 to 2,740
mm).
C-l
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The original Insituform liner installed in the Brick Lane Sewer was examined in June 1991 and two
sample panels were removed from the lining by Insituform Permaline, Ltd., and placed in the custody of
MTS Pendar, Ltd., under the scrutiny of TW. The panels were cut from the sidewall of the liner along the
spring line of the sewer about 3 ft (900 mm) from the access manhole located in Riverside Close. The
location was revisited in October 2001 and two sample panels about 1 foot (300 mm) square were
removed from an area of the sidewall about 6 ft (1.83 m) into the sewer (Figure C-l). The second set of
samples was placed in the custody of Bodycote Materials Testing, Ltd. (owners of MTS Pendar). In each
instance, test pieces were machined from the test panels and tested for flexural strength and modulus in
accordance with the relevant testing specifications: BS 2782 Part 3 Method 335A: 1978 in 1991 and
U.K.WIS 4-34-04/BS EN ISO 178 in 2001. The results of this retrospective evaluation spanning 20 to 30
years after the original CIPP installation are summarized in Table C-l.
V
Figure C-l. Sample Retrieval at the Brick Lane Sewer CIPP Project in Hackney, U.K.
Table C-l. Results of Brick Lane Sewer CIPP Retrospective Testing
Flexural Property
Modulus, MPa
Modulus, psi
Strength, MPa
Strength, psi
Sample Mean
20 Year
2,900
420,000
46
6,700
30 Year
3,300
480,000
43
6,200
Industry Standard
WIS4-34-04
2,200
-
25
-
ASTM F1216
-
250,000
-
4,500
C-2
-------
It is anticipated that Insituform Technologies, Ltd., will seek the agreement of TW to sample this unique
installation again in 2011. There is no data from the original installation which predates the formation of
the Permaline Division of Edmund Nuttall, Ltd., (now Insituform Technologies, Ltd.), nor similar data
from other installations.
Today, TW is headquartered in Reading with operational centers based on major treatment plants at
Mogden, Cross Ness, Sandford and Beckton. These operations centers use preferred contractors to
undertake emergency works which investigate flooding incidents and other system failures, its crews
identify lining needs which are passed to a lining manager based at Reading and sanctioned for
implementation, mainly using the preferred contractor Onsite Central. Other specialist contractors such
as Waterflow and Insituform can be used. Larger projects classed as capital works will be undertaken by
any of four major framework contractors appointed for the current asset management period (AMP) 5.
These contractors are B&V, Optimise, MGJV, or GBM and they are expected to utilize the preferred
specialist subcontractors.
Lining volumes are not centrally recorded, so it is difficult to estimate how much CIPP and other lining
methods have been installed. TW and its antecedents, the city and municipalities of the region have been
undertaking this type of work since before formation of TWA in 1973 and it is thought that lining
volumes have fluctuated widely from 6 to 60 km/year. Policy changes in the four five-year AMPs since
privatization have ensured that there has been no continuity of lining work. According to TW, the work
currently undertaken is customer focused on solving problems and not asset focused. In England and
Wales, according to the U.K. Water Regulator OFWAT, over this asset management period, the
proportion of sewers in condition grade 3 to 5 (the poorest conditions) has increased from 20 to 30% of
the network.
According to OFWAT, TW has renovated 408 km (254 miles) and replaced 264 km (164 miles) of critical
sewer since 1990-91. Critical sewers, in the U.K. perspective, are sewers identified for proactive
maintenance. These may be located under major roads, highways, rail tracks or in other sensitive
locations and serve critical facilities such as hospitals, major business or population centers where the
consequences of failure are major. It is thought that critical sewers make up some 20% of the network.
OFWAT has published data on renovation and replacement for non-critical sewers since 2000-01;
nationwide annual rates of rehabilitation for non-critical sewers of 87 to 91 km (54 to 57 mi)/year are
marginally lower than for critical sewers 83 to 110 km (52 to 68 mi)/year. It seems reasonable to assume
that TW may have renovated about 800 to 900 km (500 to 560 mi) of all sewers, perhaps 45 km (28 mi)
per year since 1990. Table C-2 summarizes sewer renovation data from TW and for all U.K. utilities.
Table C-2. TW and U.K. Sewer Renovation Rates for 1990 to 2010
Asset
Management
Period
AMP1 90-95
AMP2 95-00
AMPS 00-05
AMP4 05-10
Subtotal
Proposed AMP5 10-05
Thames Water
Critical
Sewers
Renovated
km
113
36
47.1
231.7
427.8
79.5
Non-Critical
Sewers
Renovated
N/A
N/A
102
118.8
>220.8
184
All U.K. Water Companies
Critical
Sewers
Renovated
km
509
711
505.4
1,162.5
2,887.9
769.4
Non-Critical
Sewers
Renovated
N/A
N/A
350.5
1,356.7
>1,707.2
3,358.9
Water
Mains
Relined
km
10,639
9,670
9,255
6,238
35,802
1,126
C-3
-------
However, the figures published by OFWAT cannot be taken at face value in terms of total rehabilitation
effort since they refer to rehabilitation activity in terms of structural enhancement. For example, a length
of condition Grade 4 or 5 sewer lined to improve condition to Grade 3 or better is deemed a valid
rehabilitation output and may be included in the volume of activity, whereas a joint sealing by CIPP in a
Grade 1 or 2 sewer may improve serviceability, but not structure and accordingly will not be counted.
The length reported may also refer to the whole section of sewer, whereas the repair may be a simple
CIPP patch repair. So the volumes of work reported as undertaken by OFWAT may be at variance with
actual lengths of lining installed by preferred contractors. The CIPP contractors themselves were
contacted for estimates of work done for TW and, on this basis, from equally fragile data, it seems more
likely that the actual volumes of CIPP undertaken for TW annually may be only about 25 to 30 km (16 to
19 mi) over the period since privatization.
The bulk of TW's experience since 1971 has been with polyester resin and felt lining, inverted with water
and hot water cured. Currently, TW's preferred lining methods include traditional polyester resin and felt
for structural improvement, epoxy resin and felt for leak tight lining (mainly for pipes 150 mm in
diameter), woven hose lining (Brawoliner) for small diameter pipes with multiple bends and UV cured
glass reinforced polyester linings for critical locations such as adjacent to rail tracks where time pressures
require rapid installations.
TW confines its work to experienced contractors, particularly Onsite and Waterflow, having had
unsatisfactory work completed by small contractors. In its experience, construction defects, if present,
become apparent within 1 to 2 years of installation. Its experience overall has been good, though some
deficiencies in older works have been identified through routine and emergency CCTV surveys where
local municipalities acting as TW agents may not have been as informed on acceptance standards and
where acceptance criteria have been improved over the years in the transition from WRc IGN 4.34.04
Issue 1 (April 1986) to the current BS12566 Part 4:2002 (see Table C-3).
Table C-3. TW Sewer Renovation Acceptance Criteria and Relevant Standards
Criterion
Appearance
Thickness
Tensile
Strength/
Modulus/
Elongation
Flexural
Strength/
Modulus/
Elongation
WRc IGN 4-34-04
Issue 1 1986
Smooth, generally free
from wrinkles, degree
of wrinkles may be
agreed by purchaser
and manufacturer
Minimum specified
and up to 15%
thicker. May be
greater where felt
layers overlap
Not less than
25MPa
1,700 MPa
1.5%
Not less than
50 MPa
2, 600 MPa
1-2.5%
WRc IGN 4.34.04
Issue 2 1995
Surface irregularities less than
6mm or tabulated value, % of
diameter, normally
longitudinal 2% in the invert
and 5% above the flowline,
circumferential 2% anywhere
Minimum specified and up to
15% thicker
NA
Not less than
Declared value < 25 MPa
Declared value
Declared value < 0.75%
BS EN 13566
Part 4:2002
Surface irregularities not more
than 2% of diameter or 6 mm
Mean thickness not less than
design thickness and minimum
not less than 80% of design
thickness or 3 mm
Not less than
Declared value < 15 MPa
N/A
Declared value < 0.5%
Not less than
Declared value < 25 MPa
Declared value < 1,500 MPa
Declared value <0.75%
C-4
-------
The main defects noted during inspections after 1 to 2 years are bulges and deformations caused by
buckling failure of poorly impregnated or cured sections and delamination of coatings.
TW operates a Dynamic Asset Condition Model based on the performance of a group of sewers initially
inspected around 1989 and reinspected periodically. Most sewers in the model focus have been inspected
at least three times since inception. The rate of deterioration is described as not significantly different
from the rate of error in identification in the survey. Over the course of the exercise, terminologies and
classification software have changed. TW used an internal classification scheme SRS2 at the outset and
moved to Examiner software and is currently transitioning towards Infonet. It is hoped that some historic
data can be reclassified using the improved system. Generally, the financing method discourages capital
maintenance, concentrating on investment in new works which enhance profitability, pipe lining is
undertaken on an as-needed basis, particularly where assets are identified as at risk of collapse within five
years.
TW has proposed a type test for CIPP systems that is applied to demonstrate water tightness (see Figure
C-2). CIPP systems satisfying this test may be selected for small diameter sewers, up to 375 mm (14.8
in.) exhibiting serious infiltration. The test (developed by WRc as a collaborative project CP308 -
infiltration reduction properties of CIPP linings) involves setting up an array of five 1 m (3.28 ft) long,
plain ended clay pipes such that the gradient is not more than 50 mm (2 in.) over the length of the test
line. The central pipe is fitted with a lateral connection through which the line may be filled to test
infiltration through the liner wall. The pipes are jointed using mechanical couplings with joint gaps set at
3 and 25 mm (0.12 and 0.98 in.). Each coupling is fitted with top and horizontal ferrule connectors. The
top ferrule connectors are fed from a header tank so as to provide a 5 m (16.4 ft) water head, the test line
is plugged and restrained before pressure testing for leakage under the 5 m head for 15 minutes.
Figure C-2. Setup for CIPP Water Tightness Test Used by TW
The lining is installed under a 3 m (9.84 ft) inversion or inflation head and cured in accordance with
manufacturers recommendations. Mechanical or hydrophilic seals which are deemed part of the system
may be fitted. The lined pipe is subjected to an external head of 5 m (16.4 ft) for 30 minutes using the
horizontal and top ferrule connections as valves in combination to simulate various conditions of
C-5
-------
exfiltration and infiltration. Any water running through the annulus between liner and test line or through
the liner wall is captured and measured. The acceptance levels for various configurations are based upon
the acceptable infiltration in new pipelines (i.e., 500 ml/m diameter/m length [1.2 gal/ft diameter/100 ft
length] over a 30 minute period at 5 m (16.4 ft) hydrostatic pressure), which is based upon BS EN 1610
"Construction and testing of drains and sewers." Epoxy resin systems (such as Epros and Brawoliner)
exhibit lower volume shrinkage and are more successful in this battery of tests than traditional polyester
resins. The UV light cure system, BKP Berolina fitted with hydrophilic end seals, has also passed the
test.
Lining thicknesses are determined by the preferred contractor using the procedures outlined in the Water
Research Centre (WRc) Sewer Rehabilitation Manual (SRM), the German Wastewater Technical
Association (Abwassertechnische Vereinigung [ATV]) method, or the ASTM method for fully-
deteriorated pipe. Preferred contractors submit a table of thicknesses with their price schedule based on
these design methods taking into account ovality and the declared physical properties of their lining
systems. Contractors also provide a quality manual covering their system and are QA tracked for
compliance to check that they are following the due procedures. Their records may be checked at random
and, early in their relationship as suppliers, there are random site visits to monitor performance. There is
no formal training for site supervision but TW's Technical Consultant (Sewerage) Don Ridgers provides
an overview of supervision and inspection. Type testing and process verification in accordance with BS
EN 13566 Part 4 is mandatory. Leak testing according to the WRc CP308 protocol is included for the
leak tight resin systems. After lining, all installations are surveyed in accordance with BS EN 13508.
CCTV information is archived, but not yet recorded on geographic information system (GIS) records. It
is expected that the Infonet data system will facilitate enhanced data storage and recovery. Where patch
repair and top hats are employed, these are inspected by CCTV for leakage and may be subject to vacuum
or air testing.
TW is very active in the process of establishing standard specifications in the U.K. and Europe for new
construction and rehabilitation; Technical Consultant (Sewerage) Don Ridgers is active as the U.K.
representative in a number of European Committee for Standardization (Comite Europeen de
Normalisation [CEN]) working groups and mirror committees, (Working Groups 12, 13 and 22) and is at
the center of an initiative to revise design methods.
Overall, TW is satisfied that its time-established system, using preferred contractors, delivers value for
the money. TW believes that, in its geology, the use of leaktight systems is important to minimizing
infiltration and, accordingly, epoxy resin linings are used for small diameter pipes prone to leakage.
C.2 Severn Trent Water (STW)
The Severn Trent Water Authority along with Thames and the other catchment-based regional water
authorities was formed in 1974 under the Water Act to supply water and wastewater services to some
7.4 million customers distributed across a large geographical area of the U.K., known as the Midlands,
which includes major cities such as Birmingham, Gloucester, Coventry, Leicester, Nottingham, Stoke,
Stafford, Wolverhampton and parts of Wales. Its regional coverage includes two major river systems, the
Severn and the Trent from which it takes its name. It is believed to be the world's fourth largest privately
owned water company and the second largest in the U.K.
Privatized in 1989, STW employs 5,686 staff and generates a turnover of U.S. $2.2 billion to maintain its
facilities, which include 28,546 miles (45,940 km) of water mains, 20 water treament works, 33,778 miles
(54,360 km) of sewers, and 1,000 sewer treatment plants. Historically, STW has played an important role
in the development of the sewer rehabilitation business in the U.K. It took a pioneering role in the
assessment of sewer condition and its staff made numerous contributions to developing knowledge at
C-6
-------
water industry conferences. A senior STW manager, George Hedley, chaired the Department of the
Environment's Committee responsible for materials used in sewer and water mains networks. In 1980, it
conducted a survey of sewers in 240 locations distributed across its territory from Shrewsbury in the west
to Scunthorpe in the east and Cheltenham in the south. The resulting analysis relating age, size,
construction material, depth and condition led to a comprehensive estimate of rehabilitation needs and
costs which had an influence on the National Water Council and the Department of the Environment and
the direction of its Water Research Centre in developing sewer rehabilitation strategies.
The reputation developed by STW in the 1980s for its expertise in the practice of rehabilitation was such
that it became respected consultants providing engineers and managers to guide overseas water agencies
such as the Delhi Jal Board and the Bombay Municipal Corporation in sewer cleaning and maintenance,
condition assessment and rehabilitation. The expertise continued after privatization when STW
purchased Haswell and Partners, a specialist consultant firm, and transfered operations engineers and
managers into the consultancy firm during a period of reorganization. Haswell Consulting Engineers
ceased to trade in 2005 and residual staff were transfered back to Severn Trent, some finding
opportunities in Severn Trent Services, Severn Trent Water's sister company.
STW has experienced significant difficulties with flooding. In 2007, flooding cost the company U.S. $50
million and affected more than 140,000 customers in and around the Gloucestershire city of Tewkesbury.
It is involved in extensive network monitoring and drainage studies, which will have future network
maintenance implications.
In the period since privatization, AMP1 through AMP4 (1991-2010), Severn Trent undertook a
significant program of sewer renewal (Table C-4). According to OFWAT statistics, it renovated 630 km
(391 mi) of critical sewer and replaced 414 km (247 mi). OFWAT commenced reporting volumes of
renovation work on non-critical sewers in 2001. Recorded volumes of non-critical sewer work within
STW are surprisingly low, a little over 25 km (16 mi). Follow-up discussions with contractors suggest
that more work has been undertaken in this area and so, as discussed in the Thames Water report, the
under and over reporting to OFWAT may be misleading and it may be reasonable to suppose that the
overall volumes of non-critical sewers lined may be similar to the volumes of critical sewers lined.
Conflicting reports were received from STW about its rehabiliation and replacment volumes in AMP4,
which perhaps confirms the difficulties of classification and interpretation described earlier. According to
STW, in AMP4 it rehabilitated 31 km (19.3 mi) of critical sewer and 10 km (6.2 mi) of non-critical sewer;
it replaced 25 km (15.5 mi) of critical sewer and 97 km (60.3 mi) of non-critical sewer.
Table C-4. STW and U.K. Sewer Renovation Rates for 1990 to 2010
Asset
Management
Period
AMP1 90-95
AMP2 95-00
AMPS 00-05
AMP4 05-10
Sub Total
Proposed AMP5 10-05
Severn Trent Water
Critical
Sewers
Renovated
km
79
221
63
271
634
96.1
Non-Critical
Sewers
Renovated
NA
NA
13
11
>24
161
All U.K. Water Companies
Critical
Sewers
Renovated
km
509
711
505.4
1162.5
2887.9
769.4
Non-Critical
Sewers
Renovated
NA
NA
350.5
1356.7
>1707.2
3358.9
Water
Mains
Relined
km
10,639
9,670
9,255
6,238
35,802
1,126
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STW uses CIPP for virtually all of its sewer renovation works and more than 90% is undertaken by the
traditional water inversion and hot water cure method. There have been air inversion and steam curing
trial projects and demonstrations of the Omega fold-and-form lining method. Some Thermopipe inflated
hose has been used for raw water and force main renovation.
The company's design and procurement procedures have changed over time as the company has evolved
through privatization. Initially, work was scoped and managed by the 2,000 agencies under STW
direction; this work was later undertaken by wholly-owned consultants Haswells and, following the
closure of the consulting firm, the work was absorbed into the regional offices. In AMP4, the regional
offices undertook feasibility studies and let work out as design-and-build projects to nominated
contractors selected by the regional engineers. Much responsibilty is placed on the design-and-build
contractors who work from the CCTV tapes and design rehabilitation works according to WIS 4-34-04
and the WRc SRM. (STW carries out a considerable amount of CCTV work - in AMP4, 1,024 km [636
mi] of critical sewer and 5,947 km [3,695 mi] of non-critical sewer were surveyed).
In AMP4, STW staff functioned as resident engineers and provided oversight on contract execution and
installation works. This will change in AMP5 when the contractors take full responsibility for their
design-and-build works. The contractors will self certify their works for compliance with the STW
specifications and STW will audit a sample of works and supervise any remedial activities required.
Overall, STW staff report that their experience has been generally good. The company reports some
problems with liner stretch, missed connections, and some wrinkling. STW has also experienced
problems rerounding severely deteriorated pipe prior to lining. Works undertaken for STW are subject to
a one-year materials and installation warranty and, where necessary, defects may be cut out and replaced.
STW places great reliance on its contractors who are appointed for each AMP period. Performance is a
key factor in contract renewal, so STW is able to call on contractors to undertake remedial works long
after the notional warranty period. STW has reported increasing problems with complaints from the
public about styrene odors.
C.3 Communaute d'Agglomeration de Chartres (CAC)
CAC was interviewed in Chartres on October 29, 2010. The interview was conducted in French with the
head of the water and wastewater service. CAC provides municipal services to the cathedral city of
Chartres and six neighboring communities. The population served is approximately 90,000. The
collection system is both separate and combined, with a total mains length of 325 km (202 mi) and
approximately 29,500 lateral connections. Operation of the collection network is under a 10-year
concession contract from 2004 to 2014 with la Compagnie des Eaux et d'Ozone, a Veolia subsidiary.
CAC first used CIPP in 2000. Total installation since then is approximately 3 to 4 km (2 to 2.5 mi) in
diameters up to 400 mm (16 in.). Current installation is approximately 0.5 km (0.3 mi) per year, and this
level is expected to increase slightly in the coming years. Typically, just one or two projects are
undertaken each year. CAC has also used grout injection in the past, but this was not successful. All
renovation is now either open trench replacement or CIPP. All of the CIPP installed is full length from
manhole to manhole. CAC has not used short patch liners, lateral liners, or top hats at connections. CAC
inspects some 15 km (9.3 mi) of sewers per year with CCTV and finds lots of defects, but does not have
the budget to rehabilitate them all. Rehabilitation and replacement runs at approximately 2.7 km (1.7 mi)
per year, so open cut replacement is the dominant method. CAC considers this to be more cost-effective
over the long-term service life than relining. Current CIPP installation is exclusively with UV-cured
methods.
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CAC has not taken samples of CIPP lining after a period in service. It has undertaken just one inspection
after a period in service in response to a problem and found both III and blockage because of a partially
collapsed liner after 8 years in service. Further rehabilitation was undertaken to rectify the problem.
CAC has its own specification for CIPP works. This was developed in house based on one used by
another municipality and amended to suit the needs of CAC. This is a performance specification that sets
material and performance standards while leaving the method itself to the contractor to decide. Design is
undertaken by contractors to meet the specification. Data sheets and test certificates of materials used are
submitted by the contractor and must include all QA certification. These must show conformance with
the specification. Pipe preparation consists of cleaning by jetting, a CCTV survey, and root removal if
necessary. This is done by the contractor under the rehabilitation contract and is considered essential to
ensure a good quality installation. Site supervision consists of monitoring of installation, the
curing/cooling cycle and any reinstatement works and is undertaken by a third party project manager.
Copies of all control documents are obtained as part of the QA process. No process verification test
samples are taken. CAC is considering adding this to the specification so that mechanical testing is
undertaken. A post-installation CCTV survey is required and is required to be repeated after one year at
the end of the warranty period, but this second inspection is not often done.
Few problems are encountered. The main ones concern poor reopening of lateral connections.
Occasional partial collapse of liners has also occurred. Lack of adhesion to the host pipe, especially at
manholes is a common problem, and grout injection is used to rectify this.
CAC uses CIPP to reinforce sewers where there is high risk of root penetration. For structural problems,
and even I/I, open cut replacement with ductile iron pipe is preferred. The condition of lateral
connections and frequent displaced pipes means that CIPP is considered ineffective in combating I/I.
CIPP is considered a maintenance activity rather than capital expenditure/asset renewal. Nevertheless
CAC expects to increase its usage of CIPP in the coming years, and to increase rehabilitation at the
expense of replacement in order to improve the network within its limited budget.
C.4 Communaute d'Agglomeration Les Hauts-de-Bievre (CAHB)
CAHB was interviewed in Paris on October 19, 2010. The interview was conducted in French with the
head of the water and wastewater service. CAHB combines several local authorities in the southwestern
suburbs of Paris, including Versailles. The population served is approximately 100,000. The collection
system is both separate and combined, with a total mains length of 450 km (280 mi) and approximately
25,000 lateral connections.
CAHB first used CIPP in 1996 when Insituform was used. The total installation since then is
approximately 30 km (18.6 mi) in diameters from 200 to 500 mm (8 to 20 in.). Current installation is
approximately 3 km (1.9 mi) per year, and this level is expected to remain unchanged in the coming
years. Most projects are quite small, less than 200 m (656 ft) in length, and there are up to 20 such
installations per year. Other rehabilitation methods used are open cut replacement, pipe bursting and
replacement with PVC when upsizing is necessary, and robotic local repairs at junctions with lateral
connections. Almost all of the CIPP installed is full length from manhole to manhole. CAHB has used
short patch liners but experience was poor and they are no longer used. No specific technical reason was
given, but funding may be a reason. The Agences d'Eau (government water agencies) that are the source
of funds for local operators do not fund short liner works as they are considered to be repairs and not
renovation. For renovation, they will fund up to 40% of the cost.
Some 3 to 5 km (1.9 to 3.1 mi) of lateral lining has been used, all installed from man-entry size sewers
rather than remotely. This is considered successful and CAHB expects to increase its usage of this
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method. Top hat repairs to junctions were trialed, but are not used. CAHB finds robotic repair to be
more cost-effective.
Current CIPP installation is almost exclusively with UV-cured methods. In the past, CAHB used hot
water-cured methods, but experience has been that UV-cured methods provide better quality and cost-
effectiveness.
CAHB has not taken samples of CIPP lining after a period in service. It has undertaken approximately 4
km (2.5 mi) of CCTV inspections after 5 and 10 years in pipes from 250 to 500 mm (10 to 20 in.)
diameter and have not identified any specific problems that raise concern over the general performance of
CIPP liners. Any anomalies or defects found are considered to be due to installation problems rather than
indicative of systemic or materials problems. Nothing that indicated any deterioration over time was
identified in the inspections.
CAHB does not have its own specification for CIPP works. Design is undertaken by contractors to a
national design method developed by Association Scientifique et Technique pour 1'Eau et
I'Environnement (ASTEE). This defines the required thickness and is checked by the consulting engineer
and project manager for conformity to the ASTEE method. No specific type testing is required, merely
verification of the design.
Pipe preparation consists of cleaning by jetting and joint sealing where necessary. Good cleaning is
considered to be important in paving the way for a successful lining, since there are fewer wrinkles and
blisters in well-cleaned lines. Also, good measurement is essential. CAHB requires the surveyor,
engineer, and contractor all to inspect and measure the line independently in advance of the work to
ensure that the correct diameter liner is used.
Contractors are required to have QA systems that conform to ISO9001, and this is considered adequate to
ensure quality. Site supervision consists of monitoring of installation and the curing/cooling cycle.
Copies of all control documents are obtained as part of the QA process.
Process verification test samples are taken from all projects and tested by a third party laboratory. The
characteristics tested are thickness and flexural modulus. Failures are rare. A post-installation CCTV
survey is also required. Watertightness testing in situ is undertaken before laterals are reopened so that
the liner itself is tested.
Few problems are encountered. The main ones concern poor reopening of lateral connections. In early
installations it was not uncommon for cutting to be in the wrong places. Also, in the early installations,
wrinkling of the liner was a common problem. Both these have now been solved.
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 represents approximately 2% of the total length
installed.
CAHB considers CIPP to be a reliable method that will remain the main one used for sewer rehabilitation
works. Good planning and pipe preparation are essential and nothing should be left to chance.
Experienced and knowledgeable consultants and contractors are also necessary for successful
installations. CAHB now enters into annual contracts with one contractor only in order to ensure
experience and quality, and does not use competitive tender for each project. While recognizing that it
could save money, CAHB considers the risk of problems due to inexperience and insufficient money to
be too high.
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C.5
Gottingen Stadtentwasserung (GS)
GS was interviewed in Gottingen on November 3, 2010. The interview was conducted in German. GS is
the drainage and wastewater service of the City of Gottingen, Germany. The population served is
130,000. The collection system is a separate system with each of the sanitary and stormwater systems
having a mains length of 375 km (233 mi) and a publicly-owned length of laterals of 300 km (186 mi).
The laterals are owned by the city as far as the property boundary.
The city council decided in 1990 to make serious investments in the wastewater system with the aim of
achieving a watertight and maintenance-free system by 2035, including the privately-owned laterals. The
annual budget is € 25 million (U.S. $33 million), all from local taxes, and GS considers that it receives
this to do the job properly and solve the problem, and not to fiddle about with minor maintenance to keep
the system going. This 45-year timeframe is exceptional and was driven by political pressure. A national
newspaper article in 1988 had been critical of the city for the state of its underground infrastructure as a
result of several large collapses, and the council in 1990 had a strong Green Party representation. As a
result of this policy and its implementation, GS is seen as a leader in wastewater system rehabilitation in
Germany.
GS was an early user of CIPP. Its first use was in 1992. Total installation of all rehabilitation methods is
shown in Table C-5.
Table C-5. Use of Rehabilitation Methods in Gottingen Stadtentwasserung, Germany
Method
CIPP
Pipe bursting (replace with PE)
PE Sliplining
PE fold & form
First Use
1992
2006
2006
2006
Total Installed (km)
42
24 incl. methods below
Incl. in above
Incl. in above
Length in past year (km)
1
7 incl. methods below
Incl. in above
Incl. in above
The total of the CIPP above that is lateral lining is approximately 6 km (3.7 mi). Of the CIPP installed, 7
km (4.4 mi) has already been replaced. In the longer term, all but about 10 km (6.2 mi) is expected to be
replaced. GS trialed short liners, but experience was poor and all were removed. The main problem was
poor resistance to water jetting during routine cleaning operations. GS also tried steel short liners, but
considered them not to be cost-effective. Similarly, GS has trialed top hats for rehabilitation of the
junction between main sewers and laterals, but again had poor experience and has ceased their use.
GS has taken samples of CIPP lining after 5 and 10 years in service, and some after 12 years. Pieces
roughly the size of a sheet of letter paper were removed in sewers 250 to 600 mm (10 to 24 in.) in
diameter. A total of 50 samples were tested by the Institut fur Unterirdische Infrastruktur gGmbH
(Institute for Underground Infrastructure [IKT]) for: E modulus; bending stiffness; thickness; and
watertightness. No results were made available, but on the basis of the results, GS considers CIPP to
have an effective service life of 50 years. GS has not confirmed the methodology for reaching this
conclusion, and review of related published reports by IKT does not provide any information that might
indicate how it was calculated.
Current CIPP installation uses UV-cured methods only. GS had a major contractual disagreement with
the leading heat-cured system supplier and switched its specification to UV-cured and has found better
quality and fewer site problems with this technology. In its specification, GS requires type testing of
materials including creep resistance and tensile and bending modulus. Minimum wall thickness is 6 mm
(0.24 in.) irrespective of design requirements.
C-ll
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All design and construction supervision is undertaken by external consulting engineers. GS considers its
role to be one of owner and facilitator, with expertise - it directs and delegates, but doesn't do the work
itself. Supervisors are required to be certified PE welders and to monitor critical site activities at any time
of day or night. Monitoring of the cooling phase (of CIPP and fold-and-form) is considered especially
important as this is where contractors cut corners to save time.
The problems encountered relate to watertightness. OS's aim is a watertight system, and after 15 years of
using CIPP, and some 15,000 watertightness tests, determined that it is an excellent long-term repair
method, but will not provide a permanently watertight system. This is due to problems of sealing ends at
manholes and of sealing the openings at lateral connections. CIPP can give a watertight pipe, but not a
watertight system. GS has switched its strategy to achieve complete system watertightness to aiming for
a 100% PE system, with welded joints throughout. When installing new pipe, only materials approved by
DVGW for gas use are allowed to be installed. This is the reason that, since 2006, PE rehabilitation
technologies have replaced CIPP at GS.
Nevertheless, it continues to use CIPP where extension of service life until PE replacement or lining is
undertaken is needed. OS's view is 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 QA/QC
approach is now credible and CIPP is considered to be a reliable repair method. In order to ensure the
quality of CIPP installation, GS requires that installers have a QA manual covering all processes and
submit it to GS in advance of undertaking any work. The supervising engineer is expected to monitor
adherence to the QA procedures set out in the manual and to prevent the contractor from cutting corners
with curing cycles, etc., in order to work more quickly. GS has noticed a reduction in prices of CIPP in
recent years and considers that this represents increased risk as contractors have to work more quickly in
order to make money, and this leads to cutting corners. GS would prefer to pay more and take less risk of
poor installation.
GS also has a policy of not rehabilitating pipe in condition class 2 or worse (Germany has five condition
classes, 0 to 4, of which 4 is the best and 0 the worst). Any sewer in classes 0 to 2 is replaced with open
cut. Rehabilitation with CIPP is only used for class 3 and 4 pipes. This is despite CIPP costing typically
one sixth to one quarter of the open cut price. Also, when CIPP is used in collectors with few lateral
connections, the lateral connections are diverted to manholes and old openings are lined over to avoid
problems of watertightness around the lateral connection junction. Manhole rehabilitation is also
undertaken, under a separate contract.
GS is a special case because of its watertight network policy. However, it was a leading adopter of CIPP
in Germany and is considered by its peers to be an expert client at a technical level, despite any
misgivings about the underlying policy. Therefore, its adoption of CIPP and its switch to PE is of
interest. As stated above, it now considers CIPP to be an excellent long-term repair technology with a
service life of 50 years and that can make individual pipes watertight. But it does not meet its
requirement of achieving a permanent, watertight network.
C.6 Technische Betriebe der Stadt Leverkusen (TBL)
TBL was interviewed in Leverkusen on November 2, 2010. The interview was conducted in German.
TBL is the technical service of the City of Leverkusen, Germany. The population served is 150,000. The
collection system is both separate and combined, with a total mains length of 660 km (410 mi) and
approximately 90,000 lateral connections.
C-12
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TBL first used CIPP in 1994. The total installation of all rehabilitation methods is shown in Table C-6.
The diameter range of CIPP undertaken is 250 to 1,200 mm (10 to 48 in.). Since 2005, its emphasis has
been on rehabilitation instead of replacement.
Table C-6. Use of Rehabilitation Methods in Technische Betriebe der Stadt Leverkusen, Germany
Method
CIPP
PE fold-and-form
First Use
1994
1998
Total Installed (km)
50
1
Length in past year (km)
5
0
All of the CIPP installed is full length from manhole to manhole. TBL trialed short liners, but they were
easily damaged by water jetting during routine cleaning operations. TBL also trialed top hats for
rehabilitation of the junction between main sewers and laterals, but again had poor experience and has
ceased their use. The problem was inability to install consistently, leaving wrinkles in the top hat, which
led to blockages in the lateral. Where repair of the junction is necessary, TBL uses grouting and Ka-Te
robotic repair methods. Where there is severe localized pipe damage, it uses mortar grouting and then
lines over the repair. Any lateral lining has been in the private part of the lateral and undertaken by the
property owners.
CIPP is now the only rehabilitation method used by TBL. The experience with PE fold-and-form was
poor. In the second project undertaken, all of the lateral re-openings were found after some months to
have moved longitudinally by approximately 150 mm (6 in.) and all laterals were blocked. This is
thought to be due to overheating in the reversion stage of the process resulting in stress relaxation over a
long period and movement of the liner. As a result, the method is no longer used.
Current CIPP installation uses UV-cured methods only. In the past, TBL used hot water curing, but has
concerns over the styrenes in the resin so it has switched its specification to UV-cured and has found
better quality and fewer site problems with this technology.
TBL has not taken samples of CIPP lining after a period in service. It has undertaken CCTV inspections
after 10 and 15 years in pipes from 250 to 1,200 mm (10 to 48 in.) diameter and has not identified any
specific problems that raise concern over the general performance of CIPP liners. It also inspects liners as
part of routine maintenance of its network. It plans to start taking coupons and testing them in the future
now that it has a larger program of CIPP works.
In its specification, TBL requires type testing of materials including creep resistance and tensile and
bending modulus. Minimum wall thickness is 5 mm (0.2 in.), irrespective of design requirements. It is
considering adding chemical resistance testing because of the large volume of industrial effluent in the
system. The largest industrial installation feeding into the system is Bayer, the pharmaceutical company
and inventor of aspirin. Structural design of liners is undertaken by the contractor and submitted for
approval to TBL. Construction supervision is undertaken partly by TBL and partly by external consulting
engineers. TBL consider this to be a critical aspect - all contractors need close supervision to ensure that
they do indeed follow the correct and agreed procedures. It has experienced contractors leaving the site
before curing is complete. All materials used must have approval from DIBt (Deutsches Institut fur
Bautechnik), but installation remains the weak area for CIPP. TBL considers that UV-cured systems have
less scope for installation errors, which is one reason for switching to this method.
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Process verification test samples are taken from all projects and sent to IKT for testing. The
characteristics tested are: watertightness; elastic modulus; bending strength; creep resistance; and
thickness. Failures of watertightness are not uncommon, whereas failures of the other properties are rare.
The problems encountered relate to watertightness. Re-survey by CCTV is undertaken after 4 years,
which is the limit of the warranty period under the German standard construction contract conditions.
TBL has undertaken watertightness tests in lined pipes up to 4 years after installation, as part of this
inspection, and several have failed. Therefore, it considers CIPP to be an adequate technology for
reduction of I/I, but that it does not lead to a watertight system. TBL also has concerns over its resistance
to water jetting used for cleaning. Its cleaning uses water jetting at 20 bar (290 psi) pressure, and TBL
reports some damage to liners from cleaning.
Nevertheless TBL continues to use CIPP. Its view is 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. TBL believes that the owner needs to take
responsibility for QA/QC and for supervision and monitoring during installation. Even with experienced
and trusted contractors the correct procedures are not always followed. For example, TBL is considering
introducing spectroscopy to its type testing to ensure that the correct resins are used. This suggests that
the level of trust between owner and installer remains low.
C.7 Public Utilities Board (PUB) Singapore
Singapore is a small (272 km2 [105 mi2]), but densely populated (5 million population) city state located
off the southernmost tip of Malaysia just 137 miles (220 km) north of the equator. PUB Singapore is the
National Water Agency responsible for collection, production, distribution, and reclamation of water.
PUB relies heavily on Malaysia for water, importing around 50% of its water demand and overtime has
been developing infrastructure to reduce reliance on its neighbor. Under its 'Four Taps Strategy,' PUB
operates 15 reservoirs for collection of rainwater, four NEWater (advanced membrane and UV
disinfection) plants, one desalination plant, and a number of undersea pipelines crossing the Straights. It
is understood that from 2011 Singapore will not seek a new water supply arrangement with Malaysia.
The drive to self-sufficiency has shaped water policy since independence and this has also impacted the
collection and processing of wastewater. Singapore invests heavily in its water industry (approximately
U.S. $3 billion since 1996).
PUB operates a very modern sewerage system, comprising six wastewater treatment plants, 130 pumping
stations, 3,400 km (2,113 mi) of gravity sewers, and 260 km (162 mi) offeree mains. It has recently
constructed a world-class Deep Tunnel Sewerage System and has taken significant steps to limit
infiltration and exfiltration, so as to improve the efficiency of its wastewater collection, treatment, and re-
use processes. Construction of the sewer network in Singapore commenced around 1910 with the
building of three sewers; anetwork of around 700 km (435 mi) existed in 1970 and thereafterthe network
was expanded at a rate of about 70 km (43 mi) per annum to its present size.
In 1993, PUB dispatched a team of its engineers to the U.K. to meet with WRc and study emerging
rehabilitation methods. It appointed Montgomery Watson (now MWH) as its rehabilitation consultant
and embarked on a major rehabilitation project (U.S. $6 million) to upgrade one of the older catchments
at Paya Lebar. The work was undertaken by a local contractor using the Formapipe CIPP system. In
1995, MOE embarked its second project (U.S. $7 million) at Pulau Saigon, lining approximately 4 km
(2.5 mi) of 150 to 600 mm (6 to 24 in.) sewer; the project again planned to used Formapipe, but the
system was acquired by Insituform and the project handed over to local licensee IPCO Insituform SE Asia
Pte (IPCO).
C-14
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Encouraged by its success in these two pilot schemes, PUB put out to tender the first of its two major
schemes to renovate the bulk of Singapore's older sewers in six subsidiary projects. Phase 1 (valued at
U.S. $105 million) involved 420 km (261 mi) of sewer and was shared by three contractors: IPCO,
Johnson Pacific using InLiner, and L&M using Permaline.
The scale of the Phase 1 project established the three companies and encouraged new competitors to
target the Phase 2 released for tender from 2001. Phase 2, nearing completion and valued at U.S. $73
million involved 350 km (217 mi) of sewer and was shared by the three contractors from Phase 1 together
with new players PRS (now Sekisui) and Jetscan, who utilized the Multiliner system. The PUB sewer
renovation program from 1993 to 2005 involved an investment of almost U.S. $200 million and addressed
problems in 800 km (497 mi) of sewers. It commenced with two small-scale projects, initially managed
with outside expert experience and concluded with two substantial schemes that established a pool of
expert contractors. The issue of contracts on this scale had a major impact on unit length pricing. The
average pricing fell from S $550/m to S $205/m (U.S. $128 to U.S. $48 per ft) in the 10-year period since
1993. There were many technical developments employed in the period, including the use of pressure
inversion vessels, resin extenders, fast cure catalysts, fiber reinforcements, and innovative scheduling to
achieve product quality and cost reduction.
In 2006, Phase 3 was released and will continue until 2012. It involves sewers and private drain lines in
the Marina Barrage Catchment. As part of the Four Taps strategy, PUB has constructed a barrage across
the mouth of the Singapore River. This U.S. $226 million dam constructed across the mouth of the river
created Singapore's 15th reservoir in 2008. It took the top prize awarded in 2009 by the American
Academy of Environmental Engineers. The Marina Reservoir is used for flood control, water storage and
recreational facilities such as boating. It is important that is not polluted by sewage and PUB has
conducted a major investigation to identify sources of exfiltration and groundwater pollution. Phase 3
will address issues identified in 600 km (373 mi) of the public sewer and private drain line network in the
Marina area. Investment is expected to be in excess of U.S. $100 million.
Phase 4, which involves 1130 km (702 mi) of sewer, is also now under way and is expected to cost a
further U.S. $100 million. It is hoped that Phase 4 will be completed in 2012. The PUB Web site
currently lists 1,264 individual projects scheduled for 2010 to 2012 and the majority involve sewer
rehabilitation. In addition to gravity sewers, PUB has relined a significant amount of sewer force mains
using Sekisui's Nordipipe product, and products from Insituform including the Kevlar reinforced liners,
InsituMain® Pressure Liner and InsituMain® Reinforced Pressure Pipe.
At the present time, PUB estimates that it has lined in excess of 1,100 km (684 mi) of the 3,400 km
(2,113 mi) network, i.e., about 30% of the wastewater collection system. In addition to CIPP (900 km
(560 mi), it has used some 120 km (75 mi) of spiral wound pipe and about 60 km (37 mi) of fold-and-
form (mainly Ex-Pipe from Australian contractor Kembla Construction). About 150 km (93 mi) of
private sewers have been lined and some 9,000 top hats installed at private sewer connections.
PUB has carried out inspections of historic rehabilitation projects, typically after about 10 years in
service. Early installations at Paya Lebar, Kim Seng Road, and Bishan Street were found to be in
generally good condition with no major defects. However, some defects have been identified, for
example, a collapsed liner in Ubi Avenue and serious longitudinal wrinkling in Geylang Road.
Much of the early work tendered by PUB was water inversion and hot water cure; however, in recent
years, some steam curing has been undertaken and it is estimated that this method amounts to about 50%
of current work. Much of the air inversion steam curing is carried out on the private drain lines in the
Marina Catchment. UV curing has also been undertaken on one project to date. Design work is
undertaken by PUB staff and by independent consultants - particularly CPG Consultants, a local
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consultant born out of the corporatization of the Public Works Department and acquired by the Australian
Downer group in 2003. Designs make reference to the tender documents and a PUB Sewerage
Rehabilitation Manual, which draws heavily on U.K. and U.S. practice and references the WRc, WIS, and
ASTM standards. PUB is rigorous on sampling and testing from installed liners and uses its engineering
staff to supervise works. However, the scale of current works is so substantial that staff are very stretched
to cover all the installation activities. Works are routinely CCTV surveyed after two years in service (i.e.,
on completion of the warranty period), and problems encountered include wrinkling, coating defects such
as blistering, and poor quality lateral reinstatement. Contractors are required to remedy defects.
The emphasis in Phases 3 and 4 on private drain lines and exfiltration has encouraged the PUB to trial
various proprietary lateral lining and top hat connection systems and this has encouraged a number of
epoxy resin system developers such as Epros, RS Lining, and MC Bauchemie to concentrate on the
Singapore market. At the present time, PUB has specified that all sewers up to 225 mm (9 in.) shall be
lined with epoxy-resin-based systems. This practice, implemented to avoid shrinkage associated with
polyester use, is not without problems because of the tropical climate experienced in Singapore. Mixing
two-component epoxy systems can give rise to difficulties with premature curing in high ambient
temperatures and when large batches are mixed. Experienced contractors such as OLiner Pte Ltd. have
equipped themselves with static mixer equipment and limited batch sizes to minimize installation risks.
Other less experienced contractors have not always been so fortunate and there is an undercurrent of
rumors about site problems. Some system providers (Epros, MC) have established local depots providing
technical support, central mixing and impregnation facilities to service less experienced contractors and
this has helped to minimize difficulties. Some system providers have also introduced resins formulated
for warmer climates.
In a recent development, the principal CIPP contractors and PUB have established, in June 2009, a
Singapore Society for Trenchless Technology (SgSTT). This body will work with PUB to establish a
good practice consensus and revise the local Sewer Rehabilitation Manual. PUB is keen to work with its
contractors to establish training and certification schemes so that all parties involved in sewer
rehabilitation can attain minimum standards. SgSTT affiliated with ISTT in November 2010 prior to the
International No Dig Conference and Exhibition to improve access to international experience and raise
standards. Current initiatives are focused on provision of CCTV and CIPP training.
PUB Consultants Private Limited (PUBC) is the commercial arm of PUB and plays strategic and active
facilitative roles in assisting PUB to achieve its goal in developing the Singapore Water industry. PUBC
harnesses PUB's operational experience and resources to support the Singapore-based water companies in
their overseas ventures in projects relating to infrastructure development and operation and maintenance
of municipal systems in water supply, used water treatment and disposal in the key markets of the Middle
East, North Africa, China, Southeast Asia, Australia and India water reclamation and recycling. It can be
expected that PUB's substantial experience in managing sewer rehabilitation projects will play a role in
PUBC activities in Southeast Asia in future years.
C.8 Brisbane Water (BW)
BW was interviewed in Brisbane on April 19, 2010. BW distributes water and collects wastewater in the
City of Brisbane, Australia. It is Australia's second largest water and wastewater utility. In July 2010, it
merged with four adjacent utilities to form Queensland Urban Utilities (QUU). QUU is jointly owned by
the five local authorities and operates as a statutory authority. QUU is one of the largest water retail
distributors in Australia, providing service to more than 1.3 million residents. This report focuses on the
experience of BW rather than that of QUU as a whole, since the adjacent utilities have minimal
experience of sewer rehabilitation. BW operates a sewer network of 6,844 km (4,253 mi) with an
additional 740 km (460 mi) of laterals. BW was the first user of CIPP for sewer rehabilitation in
C-16
-------
Australia; its first installation was in 1979. BW had already used sliplining for some 10 years prior to the
first use of CIPP.
The technologies used for sewer rehabilitation by BW are shown in Table C-7.
Table C-7. Use of Rehabilitation Methods in Brisbane, Australia
Method
CIPP
Spiral lining
Sliplining
PVC fold & form
First Use
1979
1985
1968
1985
Total Installed (km)
45 (main sewers); 330 (laterals)
25.5
9.5
28.9
Length in past year (km)
1.7
2.5
Minimal
2.2
In addition to the main sewer and lateral lining, BW has installed 660 patch repairs and 120 tees/top hats
using CIPP technology. Between 1979 and 1985, it used CIPP almost exclusively for its sewer
rehabilitation requirements. At that time there was no viable alternative to CIPP, so BW continued to use
it despite several problems. The problems encountered were:
• Where there was a high head of groundwater over the pipe, there was leakage into the pipe
during the installation. This caused holidays and areas of uncured resin. At that time,
unsaturated polyester resin was exclusively used.
• Poor bond of resin to concrete pipe. This led to risk of collapse. Liners shrunk away from
the host pipe leaving an annular space. In deep sewers this was under high pressure. One
installation was undertaken at 116 ft (35 m) deep.
• Tendency of the ends of the CIPP to contract back into the pipe when cut, leaving a length of
unlined sewer adjacent to manholes.
• Operational risk. Brisbane has a sub-tropical climate and is subject to sudden and severe
rainfall events at certain times of the year. When one of these occurs, the sewer system
quickly becomes surcharged and it is necessary to stop all works in the system. If using
CIPP, this results in a major problem as the liner is left partially cured and has to be
painstakingly removed and the work repeated.
• Installation risk. BW had one experience where an installation of 100 m (328 ft) length of
675 mm (27 in.) diameter CIPP was lost. The end plug holding the curing water blew out and
all the curing water was lost. The sewer was 10 m (32.8 ft) deep and it was not possible to
retrieve the partially cured liner, so it continued to cure, but slowly and not sufficiently to
provide the necessary rehabilitation. It had to be cut into small pieces and extracted; this
work took several months.
As a result of these problems and also due to the problems of ensuring that the line was sufficiently dry
for CIPP to cure, BW considers CIPP to be risky in sub-tropical climates and was open to alternatives.
When spiral lining and PVC fold-and-form became available in 1985, BW tested them and switched to
spiral lining as its main rehabilitation method. The more recent use of CIPP has been mainly in laterals.
Spiral lining has two practical advantages for BW:
• It can be undertaken with some flow in the pipe.
• If there is a sudden rainfall event, it can easily be removed and the work repeated.
C-17
-------
BW continues to use CIPP, mainly in laterals. The current methods used are:
• Installation: air inversion 80%; water inversion 15%; and pull-in and inflate 5%
• Curing: steam 80%; hot water 15%; and UV 5%
Recently, BW experienced a problem with a UV-cured installation. A liner failed to cure properly for
unknown reasons, but BW suspects that it was due to contractor inexperience or equipment failure. The
liner was removed by cutting it into small pieces, and successfully replaced with a similar UV-cured liner.
However, BW considers that such failures are a rarity and that the systems are generally reliable; the
technology is adequate, but that the problems occur with installers. A committed and experienced
installing contractor is necessary.
In order to ensure the quality of CIPP installation, BW has developed a specification based around the
following standards:
• EN 13566-1:2002: plastics piping systems for renovation of underground non-pressure
drainage and sewerage networks - General.
• EN 13566-4:2002: plastics piping systems for renovation of underground non-pressure
drainage and sewerage networks - Lining with CIPP.
• ISO175:1999: plastics - methods of test for the determination of the effects of immersion in
liquid chemicals.
• EN1542:1999: products and systems for the protection and repair of concrete structures. Test
methods.
• A jetting resistance test developed by BW.
• The Darmstadt abrasion resistance test.
Type testing is required for all materials used. Tests stipulated are: strain corrosion, creep, and chemical
resistance. Samples from the installation are taken and tested in a third party laboratory for thickness,
tensile modulus and watertightness. Post-installation CCTV survey is also required; it is linked to GIS
data and the data is archived for future reference. Liners are also pressure tested where their location is
considered critical, for example under embankments where the consequence of failure is high.
The above items are QA/QC data required from the contractor, but BW is moving to a system of
performance specification and requiring a guarantee from the manufacturers of proprietary products that
this can be met. Products will be allowed based on such guarantees and the performance risk placed on
the vendor.
BW has undertaken inspection of CIPP installations after a period in service. An installation from 1985
comprising 1.9 km (1.18 mi) of 12 mm (0.47 in.) thick 750 mm (30 in.) and 825 mm (32.5 in.) diameter
lining was inspected in 2002, i.e., after 17 years of service. The inspection was by CCTV only and no
defects were noted. Since then, several further inspections by CCTV and man entry have been
undertaken of this same line, and coupons taken. No defects were noted in the inspection.
Coupons have been retrieved from certain pipes when pieces have been dislodged by high pressure jetting
done for cleaning purposes, but have not been tested to establish their properties. This has raised
concerns over jetting for cleaning in CIPP-lined pipes. BW has addressed this through changing its
operational procedures for jetting by limiting pressure and using specific designs of nozzle.
C-18
-------
BW 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. The nature of sub-tropical regions is such
that it may not be well suited to work in such locations. Also the experience, capability and commitment
of the installer are considered paramount. The combination of an inexperienced client and an
inexperienced installer will lead to problems. The move to requiring guarantees from system vendors is
intended to overcome this risk.
C.9 Sydney Water (SW)
Sydney was declared the first city in Australia in 1842. By 1857, the City Council had commissioned
five sewer outfalls discharging into the harbor. A Board of Water Supply and Sewerage was established
in 1880 and Botany Sewage treatment farm was opened in 1888. Sewer collection systems were built to
serve the north, west and south of the city starting in 1898. Four major sea outfalls were built between
1916 and 1936. Inland treatment facilities were built at Fairfield and Campbelltown in 1938 and
collection systems were built at Cronulla and Port Kembla starting in 1958. The Metropolitan Water
Supply and Sewerage Board became the Sydney Water Board in 1987 and Sydney Water Corporation in
1994.
SW serves the city and suburbs, an area of some 12,700 km2 (4,900 mi2) housing a population of 4.5
million. It collects and treats 1.2 billion liters of wastewater daily. The three largest of 29 plants, located
at Malabar, North Head and Bondi, treat about 75% of the volume collected. Recycling and desalination
are major initiatives to improve water provision and it is hoped to recycle about 12% of wastewater by
2015. The wastewater collection system involves about 24,000 km (14,900 mi) of pipes, 5,500 km (3,418
mi) of laterals and 674 pumping stations. In addition, there are 443 km (275 mi) of stormwater channels
and pipes. As expected in a city of such history, the system is mature and maintenance and restoration
programs are ongoing.
SW operates a number of major pipe maintenance programs. These include: the A $560 million (U.S.
$552 million) four-year Sewerfix plan due for completion in 2012; the Northern Suburbs Ocean Outfall
System project, to clean and repair large diameter tunnels and pipes; and the targeted A$80 million (U.S.
$79 million) Wastewater System Rehabilitation Project.
SW has had a long involvement in the development and use of sewer rehabilitation methods. Rocla
Monier was among the first overseas companies to adopt the Insituform system in 1978. Sydney is
thought to be the first city in Australia to use the Insituform method. In 1992, the Insituform license was
taken over by East Coast Underground, a company which also offered the Nupipe PVC fold-and-form
system. The license was withdrawn after 3 to 4 years and Insituform contracted works directly from the
U.K. from time to time until a local operation (Insituform Pacific Pty) was established in 2007. Some 200
km (124 mi) of CIPP has been installed by SW since 1978 and currently a number of contractors
including Insituform, Kembla and Veolia offer CIPP. Water inversion and hot water cure is the preferred
installation method but air inversion and steam are in the process of introduction and some UV light
curing has been used. The Berolina and Brandenburger systems have been tried. Overall, approximately
20 km (12.5 mi) of sewer was lined with CIPP in 2009.
SW also supported the development of local technology and has been a major user of the Ribloc Spiral
Wound PVC method. It is estimated that 800 km (497 mi) of spiral wound (Ribloc and Danby) and fold-
and-form (EX Pipe) systems have been used in Sydney. Spiral wound pipes are popular in Australia.
The principal system installer is InterFlow Pty, Ltd., which holds the Ribloc license from Sekisui SPR.
This technology was developed in Australia in 1983 as a means of casting pipe in remote locations. By
1986, it had been employed for sewer lining and was taken up by Sekisui and developed in joint venture
with the Tokyo Metropolitan Government in Japan. The technology has been well utilized in the Middle
C-19
-------
East, but has not yet had marked success in Europe or North America. Since the worldwide licensed
business was acquired by Sekisui Corporation, significant marketing effort has been applied and a range
of new spiral wound products including Rib Steel and Rib Line are making some headway. In addition to
Ribloc, the Danby system was also invented in Australia and its Panel Lok is available for man-entry
sewers.
Since 1992, some 1,200 km (746 mi) of fold-and-form pipe has been installed throughout Australia; the
folded pipe material is manufactured by Vinidex. In 2009, SW lined approximately 50 km (31 mi) of
sewer with spiral wound and fold-and-form products.
For some years, SW's rehabilitation programs have been driven by inflow and infiltration reduction and
the organization has focused on both sewer mains and laterals. Generally, the private lateral is considered
as the pipe from the boundary trap to the household. In the 1990s, there was a considerable focus on
lateral lining and grouting with the Logiball system and a number of lateral lining systems have been
employed. The current policy on laterals is to line the connection with the main and some 300 to 400 mm
(12 to!6 in.) of the sewer lateral using a top hat system such as Kembla's Tiger T or Interflow's Interfit
connection seal. From 1997, SW trialed a number of different lining systems and now concentrates its
programs around CIPP, fold-and-form systems and EX Pipe for lines up to 300 mm (12 in.). SW has
recently moved away from its focus on III due to a prolonged drought affecting its catchments.
Currently, SW aims to undertake 400-500 km (250-310 mi) of CCTV work and anticipates that this will
yield a lining program covering 10-15% of pipe surveyed. The reasons for remedial work are
predominantly associated with workmanship issues arising from original construction and root intrusion.
Liner designs are undertaken as partially or fully deteriorated using ASTM F1216 for partially
deteriorated pipe and AS2566 Plastic Pipe-laying Design for fully deteriorated pipe. In this latter local
standard, the liner is designed as a new pipe. Egg shapes are designed in accordance with the WRc Sewer
Rehabilitation Manual.
The long-term flexural modulus values selected for design adopted by SW are generally those provided
by the local manufacturer or overseas system provider. Liners are predominantly resin and felt and there
is little experience of strain corrosion or chemical resistance testing. For process verification of installed
liners, restrained samples are generally taken from the liner in the manholes; one from each four to five
installations is transferred into safe custody and tested by a third-party laboratory. Usually parallel plate
testing of pipe samples is preferred to flat plate or prepared coupon samples. SW also specifies that Shore
hardness testing is undertaken for CIPP installations as a simple indicator of satisfactory curing and
impregnation. A Shore D hardness value of 60-70 is considered acceptable. The Shore hardness
durometer with its round tipped indentor is preferred to the flat tipped Barcol device and can deal with
curved surfaces.
SW inspects installed liners at the end of two years in service; problems are rarely experienced because its
shortlisted framework contractors, Interflow, Kembla Watertech and Insituform Pacific are all
substantially experienced. The main defect experienced with CIPP liners are reported to be poorly
reinstated connections. Wrinkling greater than 1% and ovality greater than 5% are regarded as defects.
SW's construction supervisors are trained in house and on the job; construction activity is monitored, but
resin mixing and impregnation are deemed to be the contractor's competency.
SW has more than 30 years of experience with CIPP and other rehabilitation methods and is involved in a
wide range of rehabilitation activity from service connections to large outfall sewers. Major programs are
ongoing.
C-20
-------
APPENDIX D
MERCURY PENETRATION POROSITY TEST REPORTS
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Page 1
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Summary Report
Penetrometer parameters
Penetrorneter: 374 - (01) 15 Bulb, 0.392 Stem, Solid
Pen. Constant: 11.007|jL/pF Pen. Weight:
Stem Volume: 0.3920 mL Max. Head Pressure:
Pen. Volume: 15.1835 mL Assembly Weight:
Hg Parameters
Adv. Contact Angle: 130.000 degrees Rec. Contact Angle:
Hg Surface Tension: 485.000 dynes/cm Hg Density:
Low Pressure:
71.1760 g
4.4500 psia
245.1800 g
130.000 degrees
13.5335 g/mL
Evacuation Pressure:
Evacuation Time:
Mercury Filling Pressure:
Equilibration Time:
Equilibration Time:
High Pressure:
50 |jmHg
5 mins
0.54 psia
10 sees
10 sees
No Blank Correction
Intrusion Data Summary
Total Intrusion Volume = 0.0967 mL/g
Total Pore Area = 31.968 m2/g
Median Pore Diameter (Volume) = 0.0286 jjm
Median Pore Diameter (Area) = 0.0048 |jm
Average Pore Diameter (4V/A) = 0.0121 jjm
Bulk Density at 0.54 psia = 1.1645 g/mL
Apparent (skeletal) Density = 1.3123 g/mL
Porosity = 11.2620 %
Stem Volume Used = 73 %
D-l
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
Page 2
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
0.54
0.77
1.01
2.02
3.01
4.01
5.50
7.00
8.50
10.50
12.99
15.98
19.96
22.95
25.02
29.99
36.75
46.64
55.91
71.26
86.40
112.35
136.89
172.00
216.55
266.75
326.80
416.49
516.92
637.69
697.19
797.45
987.87
1197.43
1297.67
1396.71
1497.27
1596.95
1696.21
1895.77
2045.35
Pore Diameter
(urn)
332.8265
236.3104
178.7894
89.5715
60.1294
45.1181
32.8603
25.8231
21.2743
17.2325
13.9282
11.3175
9.0632
7.8802
7.2287
6.0314
4.9218
3.8781
3.2348
2.5382
2.0934
1 .6098
1.3212
1.0516
0.8352
0.6780
0.5534
0.4343
0.3499
0.2836
0.2594
0.2268
0.1831
0.1510
0.1394
0.1295
0.1208
0.1133
0.1066
0.0954
0.0884
Cumulative
Pore Volume
(mL/g)
0.0000
0.0042
0.0061
0.0201
0.0287
0.0308
0.0327
0.0333
0.0339
0.0342
0.0345
0.0348
0.0352
0.0354
0.0355
0.0359
0.0360
0.0361
0.0362
0.0363
0.0364
0.0379
0.0383
0.0385
0.0386
0.0388
0.0390
0.0393
0.0395
0.0398
0.0399
0.0403
0.0406
0.0409
0.0411
0.0413
0.0414
0.0416
0.0417
0.0420
0.0422
Incremental
Pore Volume
(mL/g)
0.0000
0.0042
0.0019
0.0140
0.0086
0.0021
0.0019
0.0006
0.0006
0.0003
0.0003
0.0003
0.0003
0.0002
0.0002
0.0003
0.0001
0.0001
0.0001
0.0001
0.0001
0.0015
0.0004
0.0002
0.0001
0.0002
0.0002
0.0003
0.0003
0.0003
0.0002
0.0004
0.0003
0.0003
0.0002
0.0002
0.0002
0.0001
0.0002
0.0003
0.0002
Cumulative
Pore Area
(m2/g)
0.000
0.000
0.000
0.001
0.001
0.001
0.001
0.001
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.003
0.003
0.003
0.006
0.007
0.008
0.008
0.009
0.011
0.013
0.015
0.018
0.021
0.027
0.033
0.041
0.046
0.050
0.055
0.060
0.066
0.077
0.086
Incremental
Pore Area
(m2/g)
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.003
0.001
0.001
0.001
0.001
0.001
0.002
0.003
0.003
0.002
0.006
0.007
0.008
0.005
0.005
0.005
0.005
0.006
0.011
0.009
D-2
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
PageS
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
2195.38
2345.25
2494.90
2644.26
2694.72
2843.76
2994.37
3242.63
3492.02
3741.92
3991.68
4241.14
4486.29
4725.91
4984.93
5282.52
5481.05
5731.50
5978.42
6224.62
6474.14
6723.87
6972.33
7475.55
7974.62
8476.29
8975.63
9271.17
9569.83
10024.73
10470.36
10972.28
11472.64
11969.80
12575.52
13075.16
13623.25
13969.03
14308.11
14564.80
14969.20
Pore Diameter
(urn)
0.0824
0.0771
0.0725
0.0684
0.0671
0.0636
0.0604
0.0558
0.0518
0.0483
0.0453
0.0426
0.0403
0.0383
0.0363
0.0342
0.0330
0.0316
0.0303
0.0291
0.0279
0.0269
0.0259
0.0242
0.0227
0.0213
0.0202
0.0195
0.0189
0.0180
0.0173
0.0165
0.0158
0.0151
0.0144
0.0138
0.0133
0.0129
0.0126
0.0124
0.0121
Cumulative
Pore Volume
(mL/g)
0.0424
0.0426
0.0428
0.0430
0.0431
0.0433
0.0435
0.0439
0.0442
0.0445
0.0449
0.0454
0.0457
0.0461
0.0466
0.0471
0.0474
0.0477
0.0480
0.0483
0.0485
0.0488
0.0491
0.0497
0.0502
0.0507
0.0513
0.0516
0.0520
0.0525
0.0531
0.0537
0.0543
0.0548
0.0556
0.0562
0.0567
0.0571
0.0575
0.0578
0.0582
Incremental
Pore Volume
(mL/g)
0.0002
0.0002
0.0002
0.0002
0.0001
0.0002
0.0002
0.0003
0.0003
0.0003
0.0003
0.0006
0.0003
0.0004
0.0005
0.0005
0.0003
0.0003
0.0003
0.0003
0.0003
0.0003
0.0003
0.0005
0.0005
0.0005
0.0005
0.0003
0.0004
0.0005
0.0006
0.0006
0.0005
0.0005
0.0008
0.0005
0.0006
0.0004
0.0004
0.0003
0.0004
Cumulative
Pore Area
(m2/g)
0.095
0.106
0.117
0.129
0.135
0.147
0.161
0.182
0.208
0.234
0.262
0.314
0.344
0.383
0.433
0.488
0.525
0.562
0.600
0.639
0.678
0.721
0.764
0.851
0.943
1.040
1.143
1.208
1.296
1.411
1.545
1.684
1.817
1.958
2.182
2.332
2.501
2.616
2.734
2.832
2.976
Incremental
Pore Area
(m2/g)
0.010
0.011
0.011
0.012
0.006
0.013
0.013
0.022
0.025
0.026
0.029
0.052
0.030
0.039
0.050
0.055
0.037
0.037
0.038
0.039
0.039
0.043
0.044
0.087
0.092
0.096
0.103
0.065
0.088
0.115
0.135
0.138
0.134
0.141
0.224
0.150
0.169
0.115
0.119
0.098
0.144
D-3
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
Page 4
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
15420.78
15766.99
16171.48
16620.37
16969.08
17313.23
17668.07
18069.68
18418.26
18765.49
19164.20
19771.59
20272.19
20778.76
21181.29
21633.64
22031.44
22637.16
23187.58
23738.37
24089.02
24639.09
25040.53
25440.46
25891.56
26441.46
26941.94
27391.92
27792.81
28242.91
28993.84
29493.05
29994.09
30444.07
30893.78
31294.74
31794.42
32344.31
32894.51
33495.02
33994.86
Pore Diameter
(urn)
0.0117
0.0115
0.0112
0.0109
0.0107
0.0104
0.0102
0.0100
0.0098
0.0096
0.0094
0.0091
0.0089
0.0087
0.0085
0.0084
0.0082
0.0080
0.0078
0.0076
0.0075
0.0073
0.0072
0.0071
0.0070
0.0068
0.0067
0.0066
0.0065
0.0064
0.0062
0.0061
0.0060
0.0059
0.0059
0.0058
0.0057
0.0056
0.0055
0.0054
0.0053
Cumulative
Pore Volume
(mL/g)
0.0588
0.0592
0.0597
0.0602
0.0605
0.0609
0.0613
0.0618
0.0622
0.0626
0.0631
0.0637
0.0644
0.0651
0.0657
0.0662
0.0675
0.0681
0.0686
0.0691
0.0695
0.0700
0.0704
0.0708
0.0716
0.0722
0.0727
0.0732
0.0736
0.0740
0.0746
0.0751
0.0755
0.0759
0.0764
0.0767
0.0771
0.0776
0.0781
0.0786
0.0790
Incremental
Pore Volume
(mL/g)
0.0006
0.0004
0.0005
0.0005
0.0004
0.0004
0.0004
0.0005
0.0004
0.0004
0.0004
0.0007
0.0007
0.0006
0.0007
0.0005
0.0012
0.0006
0.0005
0.0005
0.0004
0.0005
0.0004
0.0004
0.0008
0.0006
0.0005
0.0005
0.0004
0.0004
0.0006
0.0004
0.0004
0.0004
0.0005
0.0004
0.0004
0.0005
0.0005
0.0005
0.0004
Cumulative
Pore Area
(m2/g)
3.176
3.314
3.476
3.649
3.788
3.932
4.086
4.287
4.457
4.620
4.796
5.079
5.397
5.682
5.988
6.230
6.820
7.118
7.380
7.657
7.845
8.121
8.334
8.551
9.026
9.361
9.653
9.974
10.212
10.470
10.860
11.147
1 1 .435
1 1 .700
12.010
12.254
12.560
12.894
13.225
13.591
13.909
Incremental
Pore Area
(m2/g)
0.200
0.138
0.162
0.174
0.139
0.143
0.155
0.200
0.171
0.163
0.176
0.283
0.318
0.285
0.306
0.242
0.590
0.298
0.263
0.277
0.189
0.276
0.213
0.217
0.476
0.335
0.292
0.321
0.238
0.258
0.391
0.287
0.288
0.265
0.310
0.244
0.306
0.334
0.331
0.365
0.318
D-4
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
PageS
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
34644.05
35495.53
36194.58
36993.98
37645.64
38444.59
39194.91
39993.93
40494.13
40994.47
42494.84
43342.89
43991.40
44992.86
46493.57
47990.06
49486.39
50182.66
52972.13
54469.81
55968.54
57966.30
59964.98
Pore Diameter
(urn)
0.0052
0.0051
0.0050
0.0049
0.0048
0.0047
0.0046
0.0045
0.0045
0.0044
0.0043
0.0042
0.0041
0.0040
0.0039
0.0038
0.0037
0.0036
0.0034
0.0033
0.0032
0.0031
0.0030
Cumulative
Pore Volume
(mL/g)
0.0795
0.0803
0.0808
0.0814
0.0819
0.0825
0.0831
0.0837
0.0841
0.0845
0.0856
0.0862
0.0868
0.0875
0.0885
0.0894
0.0904
0.0909
0.0925
0.0935
0.0944
0.0955
0.0967
Incremental
Pore Volume
(mL/g)
0.0005
0.0008
0.0005
0.0006
0.0005
0.0006
0.0006
0.0006
0.0004
0.0004
0.0011
0.0006
0.0005
0.0007
0.0010
0.0010
0.0010
0.0005
0.0017
0.0009
0.0009
0.0012
0.0012
Cumulative
Pore Area
(m2/g)
14.306
14.890
15.268
15.769
16.205
16.737
17.234
17.761
18.127
18.493
19.501
20.083
20.584
21.313
22.304
23.304
24.344
24.872
26.757
27.851
28.950
30.447
31.968
Incremental
Pore Area
(m2/g)
0.397
0.585
0.378
0.500
0.436
0.532
0.498
0.527
0.366
0.366
1.008
0.583
0.501
0.728
0.991
1.000
1.040
0.528
1.886
1.094
1.099
1.497
1.521
D-5
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Page 6
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Cumulative Intrusion vs Pore size
Intrusion for Cycle 1
0.09
0.00
100
1 0.1
Pore size Diameter (urn)
0. 1
D-6
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Page 7
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Incremental Intrusion vs Pore size
Intrusion for Cycle 1
0.014-
t
0.012-
0.010-
.2 0.008-
0.006-
0.004-
0.002-
0.000-
100
10
1 0.1
Pore size Diameter (|jm)
0.01
D-7
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
PageS
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Cumulative Pore Area vs Pore size
Intrusion for Cycle 1
30-
25-
20-
I
15-
10-
100
10
1
Pore size Diameter (|jm)
0.01
D-8
-------
LiLUICROMERITICS
ANALYTICAL
AutoPorelV9500V1.09
The Particle
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
Page 9
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Differential Intrusion vs Pore size
Intrusion for Cycle 1
10-
i
-£ 5-
"5
1
Q
3-
100
10
1
Pore size Diameter (|jm)
0.1
0.01
D-9
-------
LiLUICROMERITICS
ANALYTICAL
AutoPorelV9500V1.09
The Particle
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/1
Page 10
Sample: Denver Upstream-48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007920.SMP
LP Analysis Time: 1/7/2011 3:26:05PM
HP Analysis Time: 1/7/2011 4:39:09PM
Report Time: 1/14/2011 2:35:46PM
Sample Weight: 2.9639 g
Correction Type: None
Show Neg. Int: No
Log Differential Intrusion vs Pore size
0.07
Intrusion for Cycle 1
0.00
10
1 0.1
Pore size Diameter (urn)
D-10
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Page 1
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Summary Report
Penetrometer parameters
Penetrorneter: 705 - (02) 15 Bulb, 0.392 Stem, Powder
Pen. Constant: 11.117 \i\Jpf Pen. Weight:
Stem Volume: 0.3920 mL Max. Head Pressure:
Pen. Volume: 14.2463 mL Assembly Weight:
Hg Parameters
Adv. Contact Angle: 130.000 degrees Rec. Contact Angle:
Hg Surface Tension: 485.000 dynes/cm Hg Density:
Low Pressure:
73.2081 g
4.4500 psia
239.8797 g
130.000 degrees
13.5335 g/mL
Evacuation Pressure:
Evacuation Time:
Mercury Filling Pressure:
Equilibration Time:
Equilibration Time:
High Pressure:
50 |jmHg
5 mins
0.54 psia
10 sees
10 sees
No Blank Correction
Intrusion Data Summary
Total Intrusion Volume = 0.1483 mL/g
Total Pore Area = 39.720 m2/g
Median Pore Diameter (Volume) = 0.2983 jjm
Median Pore Diameter (Area) = 0.0051 ^m
Average Pore Diameter (4V/A) = 0.0149 |jm
Bulk Density at 0.54 psia = 1.0731 g/mL
Apparent (skeletal) Density = 1.2762 g/mL
Porosity = 15.9149 %
Stem Volume Used = 85 %
D-ll
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
Page 2
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
0.54
0.76
1.01
2.02
3.01
4.01
5.51
7.00
8.50
10.49
12.99
15.98
19.96
23.01
25.02
29.99
36.82
46.29
55.80
71.57
86.75
1 1 1 .45
136.04
171.86
216.81
266.99
326.85
417.10
516.99
636.72
697.38
797.94
987.62
1198.11
1297.40
1397.88
1497.41
1596.22
1696.00
1896.12
2046.05
Pore Diameter
(urn)
335.7452
237.9319
179.6617
89.5844
60.1207
45.1217
32.8460
25.8338
21.2717
17.2375
13.9219
11.3189
9.0628
7.8594
7.2288
6.0317
4.9123
3.9072
3.2411
2.5271
2.0850
1 .6228
1 .3295
1 .0524
0.8342
0.6774
0.5534
0.4336
0.3498
0.2841
0.2593
0.2267
0.1831
0.1510
0.1394
0.1294
0.1208
0.1133
0.1066
0.0954
0.0884
Cumulative
Pore Volume
(mL/g)
0.0000
0.0020
0.0038
0.0295
0.0446
0.0478
0.0499
0.0514
0.0537
0.0558
0.0586
0.0608
0.0627
0.0639
0.0644
0.0658
0.0663
0.0669
0.0673
0.0682
0.0685
0.0690
0.0693
0.0701
0.0710
0.0721
0.0727
0.0732
0.0737
0.0743
0.0745
0.0748
0.0753
0.0758
0.0760
0.0763
0.0765
0.0768
0.0770
0.0774
0.0777
Incremental
Pore Volume
(mL/g)
0.0000
0.0020
0.0019
0.0257
0.0152
0.0032
0.0021
0.0015
0.0024
0.0021
0.0028
0.0021
0.0019
0.0012
0.0005
0.0013
0.0005
0.0006
0.0005
0.0008
0.0004
0.0005
0.0003
0.0007
0.0009
0.0011
0.0005
0.0006
0.0005
0.0006
0.0002
0.0003
0.0005
0.0005
0.0002
0.0003
0.0002
0.0002
0.0002
0.0004
0.0003
Cumulative
Pore Area
(rrrVgj)
0.000
0.000
0.000
0.001
0.002
0.002
0.002
0.002
0.003
0.003
0.004
0.005
0.005
0.006
0.006
0.007
0.007
0.008
0.008
0.009
0.010
0.011
0.012
0.014
0.018
0.024
0.028
0.032
0.038
0.045
0.048
0.053
0.063
0.074
0.081
0.089
0.096
0.104
0.112
0.128
0.142
Incremental
Pore Area
(m2/g)
0.000
0.000
0.000
0.001
0.001
0.000
0.000
0.000
0.000
0.000
0.001
0.001
0.001
0.001
0.000
0.001
0.000
0.001
0.001
0.001
0.001
0.001
0.001
0.002
0.004
0.006
0.004
0.005
0.005
0.007
0.003
0.005
0.010
0.011
0.007
0.008
0.008
0.007
0.009
0.016
0.014
D-12
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
2195.52
2345.47
2494.76
2645.49
2694.23
2844.00
2994.37
3243.83
3492.37
3742.71
3991.99
4240.43
4484.77
4724.61
4982.60
5283.24
5482.35
5730.31
5976.53
6225.27
6472.55
6725.79
6971.92
7474.30
7974.95
8476.51
8975.22
9269.96
9568.27
10023.06
10468.24
10972.38
11472.17
11972.62
12576.36
13070.78
13622.13
13969.93
14308.38
14567.04
14971.25
Pore Diameter
(urn)
0.0824
0.0771
0.0725
0.0684
0.0671
0.0636
0.0604
0.0558
0.0518
0.0483
0.0453
0.0427
0.0403
0.0383
0.0363
0.0342
0.0330
0.0316
0.0303
0.0291
0.0279
0.0269
0.0259
0.0242
0.0227
0.0213
0.0202
0.0195
0.0189
0.0180
0.0173
0.0165
0.0158
0.0151
0.0144
0.0138
0.0133
0.0129
0.0126
0.0124
0.0121
Cumulative
Pore Volume
(mL/g)
0.0781
0.0784
0.0789
0.0792
0.0793
0.0796
0.0798
0.0802
0.0807
0.0811
0.0815
0.0820
0.0824
0.0828
0.0833
0.0840
0.0844
0.0848
0.0853
0.0856
0.0860
0.0865
0.0871
0.0880
0.0887
0.0894
0.0902
0.0906
0.0910
0.0916
0.0922
0.0929
0.0938
0.0948
0.0958
0.0967
0.0979
0.0985
0.0990
0.0996
0.1003
Incremental
Pore Volume
(mL/g)
0.0004
0.0003
0.0005
0.0003
0.0001
0.0003
0.0003
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
0.0005
0.0007
0.0003
0.0005
0.0005
0.0004
0.0003
0.0005
0.0006
0.0008
0.0007
0.0007
0.0008
0.0004
0.0004
0.0006
0.0006
0.0007
0.0008
0.0010
0.0011
0.0009
0.0012
0.0006
0.0006
0.0005
0.0007
Cumulative
Pore Area
(m2/g)
0.160
0.173
0.202
0.218
0.226
0.242
0.259
0.287
0.320
0.353
0.389
0.430
0.467
0.513
0.562
0.647
0.687
0.745
0.804
0.854
0.902
0.979
1.074
1.208
1.334
1.457
1.604
1.691
1.773
1.902
2.043
2.220
2.427
2.680
2.966
3.218
3.561
3.747
3.924
4.099
4.328
Incremental
Pore Area
(m2/g)
0.018
0.013
0.028
0.017
0.007
0.016
0.017
0.028
0.033
0.033
0.036
0.041
0.038
0.046
0.049
0.085
0.040
0.057
0.059
0.051
0.047
0.078
0.094
0.134
0.126
0.123
0.147
0.087
0.082
0.129
0.141
0.177
0.207
0.253
0.286
0.251
0.343
0.185
0.177
0.176
0.229
D-13
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
Page 4
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
15420.59
15768.42
16166.40
16617.40
16963.14
17319.47
17667.82
18067.91
18416.13
18765.64
19164.96
19764.62
20273.28
20777.43
21179.38
21631.86
22033.96
22636.97
23186.88
23738.84
24088.76
24640.45
25039.78
25440.51
25891.81
26441.73
26942.16
27391.61
27792.91
28242.99
28993.45
29493.95
29993.17
30443.60
30893.57
31293.66
31793.27
32344.46
32895.03
33495.38
33995.14
Pore Diameter
(urn)
0.0117
0.0115
0.0112
0.0109
0.0107
0.0104
0.0102
0.0100
0.0098
0.0096
0.0094
0.0092
0.0089
0.0087
0.0085
0.0084
0.0082
0.0080
0.0078
0.0076
0.0075
0.0073
0.0072
0.0071
0.0070
0.0068
0.0067
0.0066
0.0065
0.0064
0.0062
0.0061
0.0060
0.0059
0.0059
0.0058
0.0057
0.0056
0.0055
0.0054
0.0053
Cumulative
Pore Volume
(mL/g)
0.1009
0.1015
0.1023
0.1030
0.1035
0.1042
0.1047
0.1053
0.1059
0.1064
0.1070
0.1082
0.1090
0.1097
0.1104
0.1111
0.1122
0.1130
0.1138
0.1146
0.1151
0.1159
0.1164
0.1169
0.1175
0.1183
0.1191
0.1197
0.1202
0.1210
0.1219
0.1225
0.1230
0.1235
0.1241
0.1246
0.1252
0.1257
0.1263
0.1270
0.1275
Incremental
Pore Volume
(mL/g)
0.0006
0.0005
0.0009
0.0006
0.0005
0.0007
0.0006
0.0006
0.0006
0.0005
0.0006
0.0012
0.0008
0.0007
0.0007
0.0007
0.0011
0.0008
0.0008
0.0008
0.0005
0.0008
0.0005
0.0005
0.0006
0.0007
0.0008
0.0006
0.0005
0.0008
0.0009
0.0006
0.0005
0.0005
0.0006
0.0005
0.0006
0.0006
0.0006
0.0006
0.0005
Cumulative
Pore Area
(m2/g)
4.541
4.724
5.040
5.271
5.472
5.719
5.937
6.157
6.385
6.611
6.877
7.385
7.745
8.063
8.369
8.695
9.231
9.609
10.035
10.430
10.711
11.122
1 1 .395
1 1 .699
12.051
12.485
12.951
13.331
13.654
14.127
14.678
15.062
15.410
15.773
16.165
16.488
16.892
17.308
17.739
18.203
18.611
Incremental
Pore Area
(m2/g)
0.213
0.183
0.316
0.231
0.201
0.248
0.218
0.220
0.228
0.226
0.265
0.509
0.359
0.318
0.305
0.326
0.537
0.377
0.427
0.395
0.281
0.411
0.272
0.304
0.352
0.433
0.466
0.380
0.323
0.473
0.551
0.384
0.349
0.363
0.391
0.323
0.404
0.416
0.431
0.463
0.409
D-14
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
34644. 78
35495.32
36195.81
36994.26
37645.13
38444.51
39194.77
39994.93
40493.52
40994.74
42493.72
43344.34
43993.54
44991.98
46493.72
47988.28
49483.07
50183.38
52971.26
54469.30
55967.23
57967.82
59964.80
Pore Diameter
(urn)
0.0052
0.0051
0.0050
0.0049
0.0048
0.0047
0.0046
0.0045
0.0045
0.0044
0.0043
0.0042
0.0041
0.0040
0.0039
0.0038
0.0037
0.0036
0.0034
0.0033
0.0032
0.0031
0.0030
Cumulative
Pore Volume
(mL/g)
0.1282
0.1289
0.1296
0.1304
0.1311
0.1318
0.1325
0.1333
0.1338
0.1344
0.1356
0.1363
0.1368
0.1378
0.1389
0.1400
0.1411
0.1418
0.1436
0.1446
0.1457
0.1470
0.1483
Incremental
Pore Volume
(mL/g)
0.0006
0.0008
0.0007
0.0007
0.0007
0.0008
0.0007
0.0007
0.0006
0.0005
0.0012
0.0007
0.0006
0.0009
0.0011
0.0012
0.0011
0.0006
0.0018
0.0010
0.0010
0.0013
0.0013
Cumulative
Pore Area
(m2/g)
19.104
19.702
20.247
20.849
21 .425
22.081
22.683
23.317
23.830
24.295
25.405
26.082
26.625
27.524
28.643
29.877
31.050
31 .740
33.837
35.081
36.340
37.995
39.720
Incremental
Pore Area
(m2/g)
0.493
0.598
0.545
0.601
0.576
0.656
0.602
0.634
0.513
0.465
1.110
0.678
0.543
0.898
1.119
1.234
1.174
0.689
2.097
1.244
1.259
1.656
1.725
D-15
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Page 6
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Cumulative Intrusion vs Pore size
Intrusion for Cycle 1
0.14
0.00
100
10 1 0.1
Pore size Diameter (urn)
0.01
D-16
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Page 7
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Incremental Intrusion vs Pore size
Intrusion for Cycle 1
0.025
0.000
100
1
Pore size Diameter (|jm)
0.1
0.01
D-17
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
PageS
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Cumulative Pore Area vs Pore size
40-
Intrusion for Cycle 1
35-
30-
25-
I 20-
Q_
i
1 15-
10-
100
10
1
Pore size Diameter (|jm)
0.01
D-18
-------
LiLUICROMERITICS
ANALYTICAL
AutoPorelV9500V1.09
The Particle
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
Page 9
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Differential Intrusion vs Pore size
Intrusion for Cycle 1
12-
10-
8-
g
c
o
'«
•fc 6-
1
O
100
10
1
Pore size Diameter (|jm)
0.01
D-19
-------
LiLUICROMERITICS
ANALYTICAL
AutoPorelV9500V1.09
The Particle
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 1/1
Sample: Denver 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007921.SMP
Page 10
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 2.2503 g
Correction Type: None
Show Neg. Int: No
Log Differential Intrusion vs Pore size
Intrusion for Cycle 1
0.09-
ft-
0.08-
0.07-
0.06-
0.05-
£ 0.04-
f
Q
O
o
0.03-
0.02-
0.01-
0.00-
10
1 0.1
Pore size Diameter (urn)
D-20
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Page 1
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Summary Report
Penetrometer parameters
Penetrorneter: 640 - (03) 15 Bulb, 1.131 Stem, Solid
Pen. Constant: 21.416|jL/pF Pen. Weight:
Stem Volume: 1.1310mL Max. Head Pressure:
Pen. Volume: 15.8168 mL Assembly Weight:
Hg Parameters
Adv. Contact Angle: 130.000 degrees Rec. Contact Angle:
Hg Surface Tension: 485.000 dynes/cm Hg Density:
Low Pressure:
69.1016 g
4.4500 psia
225.4733 g
130.000 degrees
13.5335 g/mL
Evacuation Pressure:
Evacuation Time:
Mercury Filling Pressure:
Equilibration Time:
Equilibration Time:
High Pressure:
50 |jmHg
5 mins
0.54 psia
10 sees
10 sees
No Blank Correction
Intrusion Data Summary
Total Intrusion Volume = 0.0875 mL/g
Total Pore Area = 27.578 m2/g
Median Pore Diameter (Volume) = 0.0357 \xn
Median Pore Diameter (Area) = 0.0048 |jm
Average Pore Diameter (4V/A) = 0.0127 |jm
Bulk Density at 0.54psia= 1.1618 g/mL
Apparent (skeletal) Density = 1.2933 g/mL
Porosity = 10.1707 %
Stem Volume Used = 42 %
D-21
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
Page 2
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
0.54
0.76
1.01
2.02
3.01
4.01
5.51
7.00
8.50
10.49
12.99
15.98
19.96
23.01
25.02
29.99
38.00
47.48
57.00
72.78
87.96
112.67
137.26
173.09
218.06
268.26
328.13
418.31
517.92
637.92
698.59
799.15
988.83
1199.32
1298.56
1399.04
1498.57
1597.38
1697.16
1897.28
2047.22
Pore Diameter
(urn)
335.7452
237.9319
179.6617
89.5844
60.1207
45.1217
32.8460
25.8338
21.2717
17.2375
13.9219
11.3189
9.0628
7.8594
7.2288
6.0317
4.7599
3.8093
3.1732
2.4852
2.0563
1 .6053
1.3177
1 .0449
0.8294
0.6742
0.5512
0.4324
0.3492
0.2835
0.2589
0.2263
0.1829
0.1508
0.1393
0.1293
0.1207
0.1132
0.1066
0.0953
0.0883
Cumulative
Pore Volume
(mL/g)
0.0000
0.0037
0.0051
0.0104
0.0152
0.0167
0.0198
0.0205
0.0211
0.0216
0.0222
0.0226
0.0231
0.0234
0.0235
0.0239
0.0241
0.0243
0.0247
0.0251
0.0254
0.0258
0.0260
0.0263
0.0265
0.0267
0.0270
0.0309
0.0315
0.0326
0.0327
0.0330
0.0334
0.0340
0.0368
0.0373
0.0375
0.0377
0.0378
0.0382
0.0385
Incremental
Pore Volume
(mL/g)
0.0000
0.0037
0.0014
0.0053
0.0048
0.0014
0.0031
0.0007
0.0006
0.0005
0.0006
0.0005
0.0005
0.0003
0.0001
0.0004
0.0002
0.0002
0.0004
0.0004
0.0003
0.0005
0.0002
0.0003
0.0002
0.0002
0.0003
0.0039
0.0006
0.0010
0.0002
0.0003
0.0004
0.0007
0.0028
0.0005
0.0002
0.0002
0.0002
0.0004
0.0002
Cumulative
Pore Area
(rrrVgj)
0.000
0.000
0.000
0.000
0.000
0.001
0.001
0.001
0.001
0.001
0.001
0.002
0.002
0.002
0.002
0.002
0.002
0.003
0.003
0.003
0.004
0.005
0.006
0.006
0.007
0.008
0.010
0.042
0.048
0.062
0.064
0.069
0.076
0.092
0.168
0.183
0.188
0.194
0.200
0.217
0.227
Incremental
Pore Area
(m2/g)
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.001
0.000
0.001
0.001
0.001
0.001
0.001
0.002
0.032
0.006
0.013
0.003
0.005
0.007
0.016
0.077
0.014
0.006
0.006
0.006
0.017
0.010
D-22
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
2196.69
2346.64
2495.94
2646.66
2695.41
2845.17
2995.55
3245.01
3493.56
3743.89
3993.18
4241.62
4486.05
4725.81
4983.80
5284.45
5483.55
5731.52
5977.74
6226.48
6473.77
6727.02
6973.15
7475.54
7976.19
8477.75
8976.47
9271.21
9569.52
10024.32
10469.51
10973.66
11473.45
11973.92
12577.67
13072.10
13623.47
13971.28
14309.74
14568.40
14972.62
Pore Diameter
(urn)
0.0823
0.0771
0.0725
0.0683
0.0671
0.0636
0.0604
0.0557
0.0518
0.0483
0.0453
0.0426
0.0403
0.0383
0.0363
0.0342
0.0330
0.0316
0.0303
0.0290
0.0279
0.0269
0.0259
0.0242
0.0227
0.0213
0.0201
0.0195
0.0189
0.0180
0.0173
0.0165
0.0158
0.0151
0.0144
0.0138
0.0133
0.0129
0.0126
0.0124
0.0121
Cumulative
Pore Volume
(mL/g)
0.0387
0.0392
0.0395
0.0397
0.0399
0.0402
0.0404
0.0407
0.0411
0.0415
0.0421
0.0425
0.0429
0.0433
0.0437
0.0441
0.0445
0.0448
0.0451
0.0456
0.0459
0.0463
0.0467
0.0474
0.0482
0.0489
0.0495
0.0499
0.0502
0.0507
0.0512
0.0517
0.0522
0.0527
0.0533
0.0538
0.0544
0.0548
0.0551
0.0554
0.0558
Incremental
Pore Volume
(mL/g)
0.0003
0.0005
0.0002
0.0003
0.0001
0.0003
0.0002
0.0004
0.0004
0.0004
0.0006
0.0004
0.0005
0.0003
0.0004
0.0004
0.0004
0.0003
0.0004
0.0005
0.0003
0.0003
0.0004
0.0007
0.0008
0.0007
0.0006
0.0003
0.0003
0.0005
0.0005
0.0005
0.0005
0.0005
0.0006
0.0005
0.0006
0.0004
0.0004
0.0003
0.0004
Cumulative
Pore Area
(m2/g)
0.240
0.263
0.276
0.293
0.301
0.317
0.332
0.356
0.387
0.417
0.466
0.499
0.545
0.579
0.621
0.671
0.714
0.753
0.799
0.866
0.911
0.962
1.017
1.132
1.275
1.399
1.522
1.592
1.662
1.763
1.868
1.994
2.124
2.255
2.419
2.564
2.731
2.849
2.961
3.048
3.180
Incremental
Pore Area
(m2/g)
0.013
0.023
0.013
0.017
0.008
0.016
0.015
0.024
0.031
0.030
0.049
0.032
0.047
0.034
0.042
0.050
0.043
0.040
0.045
0.067
0.045
0.051
0.055
0.115
0.143
0.124
0.123
0.070
0.070
0.101
0.105
0.126
0.130
0.131
0.164
0.144
0.167
0.118
0.113
0.087
0.132
D-23
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
Page 4
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
15421.97
15769.81
16167.80
16618.81
16964.56
17320.89
17669.25
18069.34
18417.56
18767.09
19166.42
19766.10
20274.77
20778.93
21180.88
21633.37
22035.49
22638.51
23188.43
23740.40
24090.33
24642.03
25041.36
25442.10
25893.41
26443.34
26943.78
27393.24
27794.54
28244.64
28995.11
29495.62
29994.83
30445.28
30895.25
31295.34
31794.96
32346.16
32896.73
33497.09
33996.86
Pore Diameter
(urn)
0.0117
0.0115
0.0112
0.0109
0.0107
0.0104
0.0102
0.0100
0.0098
0.0096
0.0094
0.0092
0.0089
0.0087
0.0085
0.0084
0.0082
0.0080
0.0078
0.0076
0.0075
0.0073
0.0072
0.0071
0.0070
0.0068
0.0067
0.0066
0.0065
0.0064
0.0062
0.0061
0.0060
0.0059
0.0059
0.0058
0.0057
0.0056
0.0055
0.0054
0.0053
Cumulative
Pore Volume
(mL/g)
0.0563
0.0566
0.0570
0.0574
0.0579
0.0583
0.0586
0.0590
0.0594
0.0597
0.0601
0.0606
0.0611
0.0615
0.0619
0.0623
0.0626
0.0631
0.0636
0.0640
0.0644
0.0648
0.0652
0.0655
0.0659
0.0663
0.0667
0.0671
0.0674
0.0678
0.0684
0.0688
0.0691
0.0695
0.0698
0.0702
0.0705
0.0709
0.0713
0.0718
0.0721
Incremental
Pore Volume
(mL/g)
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
0.0003
0.0004
0.0005
0.0005
0.0004
0.0004
0.0004
0.0003
0.0005
0.0005
0.0005
0.0003
0.0005
0.0004
0.0003
0.0004
0.0004
0.0004
0.0004
0.0003
0.0004
0.0006
0.0004
0.0004
0.0004
0.0003
0.0003
0.0004
0.0004
0.0004
0.0004
0.0004
Cumulative
Pore Area
(m2/g)
3.326
3.448
3.588
3.749
3.909
4.056
4.200
4.349
4.491
4.628
4.793
5.016
5.217
5.419
5.593
5.776
5.945
6.193
6.422
6.662
6.835
7.083
7.286
7.477
7.696
7.942
8.173
8.386
8.598
8.830
9.178
9.431
9.684
9.929
10.160
10.379
10.636
10.919
11.210
1 1 .529
11.801
Incremental
Pore Area
(m2/g)
0.146
0.122
0.140
0.161
0.160
0.148
0.143
0.149
0.142
0.137
0.166
0.223
0.201
0.201
0.174
0.184
0.168
0.248
0.229
0.240
0.173
0.248
0.203
0.191
0.219
0.246
0.231
0.213
0.211
0.232
0.348
0.253
0.253
0.246
0.230
0.219
0.257
0.283
0.291
0.319
0.273
D-24
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
34646.50
35497.05
36197.55
36996.01
37646.89
38446.28
39196.54
39996.71
40495.30
40996.54
42495.53
43346.16
43995.36
44993.81
46495.56
47990.13
49484.93
50185.25
52973.14
54471.19
55969.13
57969.73
59966.72
Pore Diameter
(urn)
0.0052
0.0051
0.0050
0.0049
0.0048
0.0047
0.0046
0.0045
0.0045
0.0044
0.0043
0.0042
0.0041
0.0040
0.0039
0.0038
0.0037
0.0036
0.0034
0.0033
0.0032
0.0031
0.0030
Cumulative
Pore Volume
(mL/g)
0.0726
0.0732
0.0736
0.0742
0.0746
0.0751
0.0756
0.0762
0.0765
0.0769
0.0778
0.0783
0.0787
0.0793
0.0802
0.0810
0.0819
0.0823
0.0838
0.0846
0.0854
0.0865
0.0875
Incremental
Pore Volume
(mL/g)
0.0005
0.0006
0.0005
0.0005
0.0004
0.0005
0.0005
0.0005
0.0004
0.0003
0.0009
0.0005
0.0004
0.0006
0.0009
0.0008
0.0008
0.0004
0.0015
0.0008
0.0008
0.0010
0.0011
Cumulative
Pore Area
(m2/g)
12.150
12.595
12.965
13.397
13.767
14.210
14.633
15.088
15.403
15.708
16.542
1 7.044
17.453
18.053
18.925
19.801
20.706
21.187
22.897
23.868
24.878
26.193
27.578
Incremental
Pore Area
(m2/g)
0.349
0.444
0.371
0.432
0.369
0.443
0.424
0.455
0.315
0.306
0.834
0.502
0.408
0.601
0.872
0.877
0.904
0.481
1.710
0.971
1.010
1.315
1.386
D-25
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Page 6
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Cumulative Intrusion vs Pore size
Intrusion for Cycle 1
0.08
0.07
0.06
f
0.05
0.04
0.03
0.02
0.01
0.00
100
10 1 0.1
Pore size Diameter (urn)
0.01
D-26
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Page 7
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Incremental Intrusion vs Pore size
Intrusion for Cycle 1
0.0050
0.0045
0.0040
0.0035
0.0030
0.0025
0.0020
0.0015
0.0010
0.0005
0.0000
100
0.1
0.01
Pore size Diameter (|jm)
D-27
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
PageS
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Cumulative Pore Area vs Pore size
Intrusion for Cycle 1
25-
20-
I
I
10-
100
10
1
Pore size Diameter (|jm)
0.01
D-28
-------
LiLUICROMERITICS
ANALYTICAL
AutoPorelV9500V1.09
The Particle
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
Page 9
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Differential Intrusion vs Pore size
Intrusion for Cycle 1
1
Pore size Diameter (|jm)
0.1
0.01
D-29
-------
LiLUICROMERITICS
ANALYTICAL
AutoPorelV9500V1.09
The Particle
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011 Port: 2/2
Sample: Denver Downstream 48"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007922.SMP
Page 10
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:21:30PM
Report Time: 1/13/2011 1:21:31PM
Sample Weight: 5.4169 g
Correction Type: None
Show Neg. Int: No
Log Differential Intrusion vs Pore size
0.07-
0.06
Intrusion for Cycle 1
0.05
t
° 0.04
0.03
Q
o
o
0.02
0.01
0.00
10 1 0.1
Pore size Diameter (urn)
D-30
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Page 1
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Summary Report
Penetrometer parameters
Penetrorneter: 707 - (02) 15 Bulb, 0.392 Stem, Powder
Pen. Constant: 11.007|jL/pF Pen. Weight:
Stem Volume: 0.3920 mL Max. Head Pressure:
Pen. Volume: 14.1733 mL Assembly Weight:
Hg Parameters
Adv. Contact Angle: 130.000 degrees Rec. Contact Angle:
Hg Surface Tension: 485.000 dynes/cm Hg Density:
Low Pressure:
73.8245 g
4.4500 psia
238.0465 g
130.000 degrees
13.5335 g/mL
Evacuation Pressure:
Evacuation Time:
Mercury Filling Pressure:
Equilibration Time:
Equilibration Time:
High Pressure:
50 |jmHg
5 mins
0.54 psia
10 sees
10 sees
No Blank Correction
Intrusion Data Summary
Total Intrusion Volume = 0.0695 mL/g
Total Pore Area = 27.968 m2/g
Median Pore Diameter (Volume) = 0.0138 jjm
Median Pore Diameter (Area) = 0.0047 |jm
Average Pore Diameter (4V/A) = 0.0099 jjm
Bulk Density at 0.54 psia = 1.1739 g/mL
Apparent (skeletal) Density = 1.2782 g/mL
Porosity = 8.1629 %
Stem Volume Used = 46 %
D-31
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
Page 2
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
0.54
0.76
1.01
2.02
3.01
4.01
5.51
7.00
8.50
10.49
12.99
15.98
19.96
23.01
25.02
29.99
36.64
46.53
56.57
71.07
86.14
1 1 1 .66
136.49
171.07
216.87
267.27
326.24
416.96
516.59
636.23
697.57
798.04
987.61
1195.62
1297.35
1396.17
1493.66
1594.81
1696.41
1893.81
2045.53
Pore Diameter
(Mm)
335.7452
237.9319
179.6617
89.5844
60.1207
45.1217
32.8460
25.8338
21.2717
17.2375
13.9219
11.3189
9.0628
7.8594
7.2288
6.0317
4.9368
3.8866
3.1970
2.5448
2.0996
1.6198
1.3251
1 .0572
0.8340
0.6767
0.5544
0.4338
0.3501
0.2843
0.2593
0.2266
0.1831
0.1513
0.1394
0.1295
0.1211
0.1134
0.1066
0.0955
0.0884
Cumulative
Pore Volume
(mL/g)
0.0000
0.0016
0.0025
0.0068
0.0089
0.0094
0.0100
0.0106
0.0111
0.0118
0.0126
0.0143
0.0165
0.0175
0.0179
0.0186
0.0188
0.0191
0.0194
0.0197
0.0199
0.0202
0.0203
0.0205
0.0206
0.0208
0.0209
0.0211
0.0212
0.0214
0.0216
0.0217
0.0220
0.0223
0.0224
0.0225
0.0227
0.0228
0.0229
0.0232
0.0233
Incremental
Pore Volume
(mL/g)
0.0000
0.0016
0.0009
0.0043
0.0021
0.0006
0.0006
0.0006
0.0005
0.0007
0.0008
0.0017
0.0023
0.0010
0.0004
0.0007
0.0002
0.0004
0.0003
0.0003
0.0002
0.0002
0.0002
0.0001
0.0002
0.0001
0.0001
0.0002
0.0002
0.0002
0.0001
0.0002
0.0003
0.0003
0.0001
0.0001
0.0001
0.0001
0.0001
0.0002
0.0002
Cumulative
Pore Area
(m2/g)
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.001
0.001
0.001
0.001
0.002
0.003
0.003
0.003
0.004
0.004
0.004
0.005
0.005
0.005
0.006
0.006
0.007
0.008
0.009
0.010
0.012
0.014
0.016
0.018
0.024
0.030
0.034
0.038
0.042
0.047
0.052
0.061
0.068
Incremental
Pore Area
(m2/g)
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.001
0.001
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.001
0.000
0.000
0.001
0.001
0.001
0.001
0.002
0.002
0.002
0.003
0.005
0.007
0.004
0.004
0.004
0.004
0.005
0.009
0.008
D-32
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
2195.55
2344.40
2493.66
2644.42
2693.29
2844.32
2995.52
3244.44
3493.68
3743.33
3992.11
4240.83
4486.94
4726.09
4984.19
5283.58
5481.82
5733.11
5978.96
6229.66
6479.13
6727.29
6977.00
7477.26
7974.45
8474.48
8974.24
9270.13
9570.45
10020.53
10473.12
10970.08
11472.44
11969.78
12571.86
13066.47
13618.66
13968.93
14303.98
14562.73
14958.84
Pore Diameter
(urn)
0.0824
0.0771
0.0725
0.0684
0.0672
0.0636
0.0604
0.0557
0.0518
0.0483
0.0453
0.0426
0.0403
0.0383
0.0363
0.0342
0.0330
0.0315
0.0302
0.0290
0.0279
0.0269
0.0259
0.0242
0.0227
0.0213
0.0202
0.0195
0.0189
0.0180
0.0173
0.0165
0.0158
0.0151
0.0144
0.0138
0.0133
0.0129
0.0126
0.0124
0.0121
Cumulative
Pore Volume
(mL/g)
0.0235
0.0236
0.0238
0.0240
0.0241
0.0243
0.0244
0.0247
0.0249
0.0252
0.0255
0.0257
0.0261
0.0263
0.0266
0.0269
0.0272
0.0274
0.0277
0.0280
0.0282
0.0285
0.0288
0.0292
0.0297
0.0302
0.0307
0.0310
0.0313
0.0318
0.0322
0.0327
0.0332
0.0337
0.0343
0.0348
0.0353
0.0357
0.0361
0.0362
0.0367
Incremental
Pore Volume
(mL/g)
0.0002
0.0002
0.0002
0.0002
0.0001
0.0002
0.0002
0.0003
0.0003
0.0003
0.0003
0.0003
0.0003
0.0003
0.0003
0.0003
0.0002
0.0003
0.0003
0.0003
0.0003
0.0003
0.0003
0.0005
0.0005
0.0005
0.0005
0.0003
0.0003
0.0005
0.0005
0.0004
0.0005
0.0005
0.0006
0.0005
0.0005
0.0004
0.0004
0.0002
0.0005
Cumulative
Pore Area
(m2/g)
0.076
0.084
0.094
0.104
0.108
0.118
0.130
0.148
0.167
0.188
0.210
0.233
0.266
0.292
0.323
0.359
0.386
0.420
0.453
0.491
0.528
0.567
0.609
0.684
0.771
0.859
0.953
1.010
1.076
1.173
1.279
1.380
1.510
1.637
1.795
1.941
2.098
2.212
2.329
2.382
2.536
Incremental
Pore Area
(m2/g)
0.008
0.008
0.010
0.010
0.004
0.011
0.011
0.018
0.019
0.021
0.022
0.023
0.033
0.026
0.031
0.036
0.027
0.034
0.033
0.038
0.037
0.039
0.041
0.075
0.087
0.088
0.095
0.056
0.066
0.098
0.106
0.101
0.130
0.127
0.158
0.146
0.156
0.114
0.118
0.053
0.154
D-33
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
Page 4
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
15413.88
15766.83
16165.42
16614.87
16965.68
17314.12
17654.82
18067.87
18414.94
18760.10
19161.77
19765.62
20266.23
20772.99
21174.21
21628.20
22031.46
22633.96
23184.30
23735.30
24085.35
24636.08
25037.47
25437.17
25887.75
26438.43
26938.92
27388.66
27789.53
28239.83
28989.15
29488.39
29977.85
30439.00
30887.07
31282.47
31786.99
32330.73
32867.55
33457.40
33947.88
Pore Diameter
(urn)
0.0117
0.0115
0.0112
0.0109
0.0107
0.0104
0.0102
0.0100
0.0098
0.0096
0.0094
0.0092
0.0089
0.0087
0.0085
0.0084
0.0082
0.0080
0.0078
0.0076
0.0075
0.0073
0.0072
0.0071
0.0070
0.0068
0.0067
0.0066
0.0065
0.0064
0.0062
0.0061
0.0060
0.0059
0.0059
0.0058
0.0057
0.0056
0.0055
0.0054
0.0053
Cumulative
Pore Volume
(mL/g)
0.0371
0.0375
0.0379
0.0383
0.0387
0.0391
0.0394
0.0398
0.0402
0.0404
0.0408
0.0414
0.0419
0.0423
0.0427
0.0431
0.0435
0.0440
0.0445
0.0451
0.0451
0.0457
0.0461
0.0464
0.0468
0.0473
0.0477
0.0480
0.0484
0.0487
0.0493
0.0497
0.0501
0.0505
0.0508
0.0512
0.0516
0.0520
0.0524
0.0528
0.0532
Incremental
Pore Volume
(mL/g)
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
0.0003
0.0004
0.0004
0.0002
0.0005
0.0006
0.0004
0.0005
0.0003
0.0004
0.0004
0.0005
0.0005
0.0006
0.0000
0.0006
0.0004
0.0004
0.0004
0.0004
0.0004
0.0003
0.0003
0.0004
0.0006
0.0004
0.0004
0.0004
0.0003
0.0003
0.0004
0.0004
0.0004
0.0004
0.0004
Cumulative
Pore Area
(m2/g)
2.683
2.810
2.952
3.113
3.247
3.386
3.521
3.675
3.839
3.908
4.102
4.359
4.551
4.763
4.924
5.134
5.306
5.564
5.812
6.118
6.118
6.449
6.644
6.839
7.060
7.318
7.569
7.778
7.991
8.220
8.569
8.827
9.100
9.370
9.584
9.808
10.088
10.385
10.697
1 1 .020
11.313
Incremental
Pore Area
(m2/g)
0.147
0.127
0.142
0.161
0.134
0.139
0.135
0.154
0.163
0.070
0.193
0.257
0.192
0.212
0.161
0.210
0.172
0.258
0.248
0.306
0.000
0.331
0.194
0.196
0.221
0.257
0.252
0.209
0.213
0.229
0.350
0.258
0.273
0.270
0.214
0.224
0.280
0.297
0.313
0.323
0.293
D-34
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
34598.98
35444.09
36143.39
36942.55
37593.96
38396.88
39145.35
39943.96
40446.18
40944.14
42445.48
43295.18
43942.78
44944.67
46446.68
47947.35
49448.08
50146.62
52949.35
54446.35
55945.20
57941.40
59925.91
Pore Diameter
(urn)
0.0052
0.0051
0.0050
0.0049
0.0048
0.0047
0.0046
0.0045
0.0045
0.0044
0.0043
0.0042
0.0041
0.0040
0.0039
0.0038
0.0037
0.0036
0.0034
0.0033
0.0032
0.0031
0.0030
Cumulative
Pore Volume
(mL/g)
0.0537
0.0543
0.0549
0.0554
0.0559
0.0564
0.0569
0.0575
0.0579
0.0583
0.0592
0.0598
0.0602
0.0609
0.0618
0.0627
0.0636
0.0641
0.0656
0.0665
0.0673
0.0685
0.0695
Incremental
Pore Volume
(mL/g)
0.0004
0.0006
0.0005
0.0006
0.0004
0.0006
0.0005
0.0006
0.0004
0.0004
0.0010
0.0006
0.0004
0.0006
0.0009
0.0009
0.0009
0.0005
0.0016
0.0009
0.0009
0.0011
0.0011
Cumulative
Pore Area
(m2/g)
1 1 .653
12.154
12.568
13.040
13.393
13.866
14.298
14.787
15.125
15.461
16.340
16.877
17.309
17.947
18.866
19.821
20.800
21.311
23.078
24.089
25.139
26.577
27.968
Incremental
Pore Area
(m2/g)
0.340
0.500
0.415
0.472
0.353
0.473
0.432
0.488
0.338
0.336
0.879
0.538
0.431
0.639
0.919
0.955
0.979
0.511
1.767
1.011
1.050
1.438
1.390
D-35
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Page 6
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Cumulative Intrusion vs Pore size
0.07-
0.06
0.05
Intrusion for Cycle 1
f
0.04
.>
0.03
E
=j
O
0.02
0.01
0.00
100
10 1 0.1
Pore size Diameter (jjm)
0.01
D-36
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Page 7
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Incremental Intrusion vs Pore size
0.0040
0.0005
0.0000
Intrusion for Cycle 1
100
1 0.1
Pore size Diameter (|jm)
0.01
D-37
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
PageS
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Cumulative Pore Area vs Pore size
Intrusion for Cycle 1
25-
20-
I
I
10-
100
10
1
Pore size Diameter (|jm)
0.01
D-38
-------
AutoPorelV9500V1.09
Li^jICROMERITICS
ANALYTICAL TT^nagrticle
CERVICES Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007923.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Differential Intrusion vs Pore size
Intrusion for Cycle 1
10-
E. '
I
0
5 5-
3
100
10
1
Pore size Diameter (|jm)
0.01
D-39
-------
LiLUICROMERITICS
ANALYTICAL
AutoPorelV9500V1.09
The Particle
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 3/1
Page 10
Sample: Columbus 8"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007923.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/14/2011 2:36:35PM
Sample Weight: 2.6206 g
Correction Type: None
Show Neg. Int: No
Log Differential Intrusion vs Pore size
Intrusion for Cycle 1
0.07
0.00
Pore size Diameter (um)
D-40
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Page 1
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Summary Report
Penetrometer parameters
Penetrorneter: 751 - (03) 15 Bulb, 1.131 Stem, Solid
Pen. Constant: 22.065 ^L/pF Pen. Weight:
Stem Volume: 1.1310mL Max. Head Pressure:
Pen. Volume: 16.3057 mL Assembly Weight:
Hg Parameters
Adv. Contact Angle: 130.000 degrees Rec. Contact Angle:
Hg Surface Tension: 485.000 dynes/cm Hg Density:
Low Pressure:
68.5930 g
4.4500 psia
236.1535 g
130.000 degrees
13.5335 g/mL
Evacuation Pressure:
Evacuation Time:
Mercury Filling Pressure:
Equilibration Time:
Equilibration Time:
High Pressure:
50 |jmHg
5 mins
0.54 psia
10 sees
10 sees
No Blank Correction
Intrusion Data Summary
Total Intrusion Volume = 0.1631 mL/g
Total Pore Area = 31.836 mz/g
Median Pore Diameter (Volume) = 6.4576 jjm
Median Pore Diameter (Area) = 0.0049 |jm
Average Pore Diameter (4V/A) = 0.0205 jjm
Bulk Density at 0.54 psia = 1.0884 g/mL
Apparent (skeletal) Density = 1.3233 g/mL
Porosity = 17.7519 %
Stem Volume Used = 67 %
D-41
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
Page 2
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
0.54
0.76
1.01
2.02
3.01
4.01
5.51
7.00
8.50
10.49
12.99
15.98
19.96
23.01
25.02
29.99
35.68
45.55
55.57
70.03
85.06
110.53
135.34
169.90
215.68
266.06
325.02
415.73
515.35
634.97
696.29
796.77
986.33
1193.98
1296.08
1394.89
1492.38
1593.53
1695.13
1892.53
2044.26
Pore Diameter
(Mm)
335.7452
237.9319
179.6617
89.5844
60.1207
45.1217
32.8460
25.8338
21.2717
17.2375
13.9219
11.3189
9.0628
7.8594
7.2288
6.0317
5.0695
3.9709
3.2549
2.5827
2.1262
1 .6363
1 .3364
1 .0645
0.8386
0.6798
0.5565
0.4350
0.3510
0.2848
0.2598
0.2270
0.1834
0.1515
0.1395
0.1297
0.1212
0.1135
0.1067
0.0956
0.0885
Cumulative
Pore Volume
(mL/g)
0.0000
0.0026
0.0053
0.0222
0.0355
0.0474
0.0567
0.0607
0.0628
0.0681
0.0706
0.0751
0.0770
0.0791
0.0798
0.0825
0.0831
0.0852
0.0867
0.0892
0.0914
0.0945
0.0961
0.0973
0.0987
0.0999
0.1008
0.1018
0.1023
0.1043
0.1047
0.1052
0.1057
0.1061
0.1063
0.1065
0.1067
0.1070
0.1072
0.1076
0.1079
Incremental
Pore Volume
(mL/g)
0.0000
0.0026
0.0027
0.0169
0.0134
0.0119
0.0093
0.0040
0.0022
0.0053
0.0025
0.0045
0.0019
0.0021
0.0007
0.0027
0.0006
0.0021
0.0015
0.0024
0.0022
0.0031
0.0017
0.0011
0.0014
0.0012
0.0010
0.0009
0.0005
0.0019
0.0004
0.0005
0.0005
0.0004
0.0002
0.0002
0.0002
0.0002
0.0002
0.0004
0.0003
Cumulative
Pore Area
(m2/g)
0.000
0.000
0.000
0.001
0.001
0.002
0.003
0.004
0.004
0.005
0.006
0.007
0.008
0.009
0.009
0.011
0.011
0.013
0.015
0.018
0.022
0.029
0.033
0.037
0.043
0.049
0.055
0.063
0.068
0.093
0.099
0.107
0.117
0.127
0.133
0.139
0.146
0.153
0.162
0.177
0.189
Incremental
Pore Area
(m2/g)
0.000
0.000
0.000
0.001
0.001
0.001
0.001
0.001
0.000
0.001
0.001
0.001
0.001
0.001
0.000
0.002
0.000
0.002
0.002
0.003
0.004
0.007
0.004
0.004
0.006
0.007
0.006
0.008
0.005
0.024
0.006
0.008
0.010
0.010
0.006
0.006
0.007
0.008
0.008
0.015
0.013
D-42
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
2194.28
2343.12
2492.38
2643.14
2692.02
2843.04
2994.25
3243.17
3492.41
3742.06
3990.84
4239.57
4485.68
4724.82
4982.93
5282.32
5480.57
5731.86
5977.71
6228.41
6477.88
6726.03
6975.75
7476.01
7973.21
8473.23
8973.00
9268.90
9569.22
10019.30
10471.89
10968.85
11471.22
11968.56
12570.65
13065.27
13617.45
13967.73
14302.79
14561.53
14957.65
Pore Diameter
(urn)
0.0824
0.0772
0.0726
0.0684
0.0672
0.0636
0.0604
0.0558
0.0518
0.0483
0.0453
0.0427
0.0403
0.0383
0.0363
0.0342
0.0330
0.0316
0.0303
0.0290
0.0279
0.0269
0.0259
0.0242
0.0227
0.0213
0.0202
0.0195
0.0189
0.0181
0.0173
0.0165
0.0158
0.0151
0.0144
0.0138
0.0133
0.0129
0.0126
0.0124
0.0121
Cumulative
Pore Volume
(mL/g)
0.1081
0.1084
0.1087
0.1090
0.1091
0.1093
0.1095
0.1099
0.1101
0.1104
0.1107
0.1111
0.1115
0.1118
0.1122
0.1126
0.1129
0.1132
0.1137
0.1142
0.1148
0.1152
0.1155
0.1161
0.1167
0.1172
0.1178
0.1181
0.1184
0.1190
0.1197
0.1203
0.1208
0.1214
0.1220
0.1226
0.1233
0.1238
0.1242
0.1246
0.1251
Incremental
Pore Volume
(mL/g)
0.0002
0.0003
0.0003
0.0003
0.0001
0.0002
0.0002
0.0003
0.0003
0.0003
0.0003
0.0004
0.0004
0.0004
0.0003
0.0004
0.0003
0.0004
0.0005
0.0005
0.0006
0.0004
0.0003
0.0006
0.0005
0.0005
0.0006
0.0003
0.0003
0.0005
0.0008
0.0005
0.0006
0.0005
0.0007
0.0005
0.0008
0.0004
0.0005
0.0003
0.0005
Cumulative
Pore Area
(m2/g)
0.201
0.214
0.230
0.248
0.257
0.269
0.283
0.305
0.327
0.349
0.376
0.408
0.445
0.481
0.515
0.566
0.599
0.643
0.707
0.773
0.855
0.914
0.963
1.062
1.152
1.249
1.356
1.421
1.493
1.607
1.784
1.912
2.049
2.183
2.364
2.516
2.748
2.877
3.022
3.132
3.301
Incremental
Pore Area
(m2/g)
0.011
0.013
0.016
0.018
0.009
0.013
0.014
0.021
0.022
0.023
0.027
0.032
0.037
0.036
0.034
0.051
0.033
0.044
0.064
0.066
0.082
0.059
0.050
0.098
0.090
0.097
0.107
0.065
0.072
0.114
0.177
0.129
0.137
0.134
0.181
0.152
0.232
0.129
0.145
0.110
0.169
D-43
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
Page 4
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
15412.68
15765.63
16164.22
16613.68
16964.49
17312.93
17653.64
18066.69
18413.77
18758.92
19160.60
19764.46
20265.07
20771.84
21173.05
21627.05
22030.31
22632.82
23183.16
23734.17
24084.21
24634.95
25036.34
25436.04
25886.63
26437.31
26937.80
27387.54
27788.41
28238.72
28988.04
29487.28
29976.75
30437.91
30885.98
31281.38
31785.90
32329.64
32866.47
33456.32
33946.80
Pore Diameter
(urn)
0.0117
0.0115
0.0112
0.0109
0.0107
0.0104
0.0102
0.0100
0.0098
0.0096
0.0094
0.0092
0.0089
0.0087
0.0085
0.0084
0.0082
0.0080
0.0078
0.0076
0.0075
0.0073
0.0072
0.0071
0.0070
0.0068
0.0067
0.0066
0.0065
0.0064
0.0062
0.0061
0.0060
0.0059
0.0059
0.0058
0.0057
0.0056
0.0055
0.0054
0.0053
Cumulative
Pore Volume
(mL/g)
0.1258
0.1264
0.1270
0.1276
0.1280
0.1284
0.1288
0.1292
0.1296
0.1300
0.1304
0.1310
0.1315
0.1321
0.1327
0.1331
0.1336
0.1343
0.1348
0.1354
0.1359
0.1364
0.1369
0.1373
0.1378
0.1383
0.1389
0.1394
0.1399
0.1403
0.1409
0.1414
0.1419
0.1423
0.1427
0.1431
0.1436
0.1441
0.1446
0.1451
0.1456
Incremental
Pore Volume
(mL/g)
0.0007
0.0006
0.0007
0.0006
0.0004
0.0005
0.0004
0.0004
0.0004
0.0004
0.0004
0.0006
0.0006
0.0006
0.0005
0.0005
0.0004
0.0007
0.0006
0.0006
0.0004
0.0005
0.0005
0.0004
0.0005
0.0006
0.0006
0.0005
0.0004
0.0004
0.0006
0.0005
0.0005
0.0004
0.0004
0.0004
0.0005
0.0005
0.0005
0.0005
0.0005
Cumulative
Pore Area
(m2/g)
3.535
3.732
3.963
4.163
4.311
4.484
4.631
4.807
4.959
5.105
5.275
5.531
5.781
6.034
6.288
6.518
6.730
7.064
7.366
7.677
7.898
8.193
8.449
8.683
8.966
9.285
9.620
9.924
10.188
10.451
10.857
11.167
1 1 .470
1 1 .750
12.052
12.316
12.639
13.012
13.380
13.766
14.147
Incremental
Pore Area
(m2/g)
0.234
0.197
0.231
0.200
0.147
0.174
0.146
0.177
0.152
0.146
0.170
0.256
0.250
0.253
0.253
0.230
0.213
0.333
0.302
0.311
0.221
0.296
0.255
0.235
0.283
0.319
0.335
0.304
0.264
0.263
0.406
0.310
0.303
0.280
0.302
0.264
0.324
0.372
0.368
0.386
0.381
D-44
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
PageS
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Tabular Report
Pressure
(psia)
34597.91
35443.03
36142.33
36941.50
37592.91
38395.83
39144.31
39942.93
40445.14
40943.10
42444.46
43294.16
43941.76
44943.66
46445.68
47946.36
49447.10
50145.64
52948.39
54445.40
55944.26
57940.48
59925.00
Pore Diameter
(urn)
0.0052
0.0051
0.0050
0.0049
0.0048
0.0047
0.0046
0.0045
0.0045
0.0044
0.0043
0.0042
0.0041
0.0040
0.0039
0.0038
0.0037
0.0036
0.0034
0.0033
0.0032
0.0031
0.0030
Cumulative
Pore Volume
(mL/g)
0.1462
0.1469
0.1474
0.1481
0.1486
0.1493
0.1499
0.1505
0.1510
0.1514
0.1525
0.1531
0.1536
0.1543
0.1552
0.1561
0.1571
0.1576
0.1592
0.1601
0.1609
0.1620
0.1631
Incremental
Pore Volume
(mL/g)
0.0006
0.0007
0.0006
0.0006
0.0006
0.0006
0.0006
0.0007
0.0004
0.0005
0.0011
0.0006
0.0005
0.0007
0.0010
0.0009
0.0009
0.0005
0.0016
0.0010
0.0008
0.0011
0.0011
Cumulative
Pore Area
(m2/g)
14.567
15.071
15.538
16.046
16.511
17.044
17.573
18.143
18.510
18.939
19.925
20.489
20.946
21.618
22.591
23.553
24.552
25.099
26.921
28.075
29.035
30.433
31.836
Incremental
Pore Area
(m2/g)
0.421
0.504
0.466
0.508
0.465
0.534
0.529
0.570
0.368
0.429
0.986
0.564
0.457
0.672
0.973
0.962
1.000
0.547
1.823
1.153
0.960
1.398
1.403
D-45
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Page 6
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Cumulative Intrusion vs Pore size
0.16
0.00
Intrusion for Cycle 1
100
10 1 0.1
Pore size Diameter (jjm)
0.01
D-46
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Page 7
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Incremental Intrusion vs Pore size
0.016
0.000
Intrusion for Cycle 1
100
1 0.1
Pore size Diameter (|jm)
0.01
D-47
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
PageS
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Cumulative Pore Area vs Pore size
Intrusion for Cycle 1
30-
25-
20-
I
15-
10-
100
10
1
Pore size Diameter (|jm)
0.01
D-48
-------
AutoPorelV9500V1.09
Li^jICROMERITICS
ANALYTICAL TT^nagrticle
CERVICES Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011\01JAN\1007924.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Differential Intrusion vs Pore size
Intrusion for Cycle 1
10-
E. '
I
0
5 5-
100
10
1
Pore size Diameter (|jm)
0.01
D-49
-------
U!UICROMERITICS
t^sNALYTICAL
AutoPore IV 9500 V1.09
Testing
Authority
Micromeritics Instrument Corporation
Serial: 1011/886 Port: 4/2
Page 10
Sample: Columbus 36"
Operator: CB
Submitter: Louisiana Tech University
File: C:\9500\DATA\2011 \01JAN\1007924.SMP
LP Analysis Time: 1/7/2011 5:32:42PM
HP Analysis Time: 1/13/2011 1:34:06PM
Report Time: 1/13/2011 1:34:07PM
Sample Weight: 4.6449 g
Correction Type: None
Show Neg. Int: No
Log Differential Intrusion vs Pore size
0.09-
Intrusion for Cycle 1
0.00
100
10 1 0.1
Pore size Diameter (jjm)
0.01
D-50
------- |