Testing and Performance Evaluation of an Innovative ...

EPA/600/R-15/326 | w ww2.epa.gov/water-research

TESTING AND PERFORMANCE EVALUATION OF AN INNOVATIVE INTERNAL PIPE SEALING SYSTEM FOR WASTEWATER MAIN REHABILITATION

Office of Research and Developemnt Water Supply and Water Resources Division

TESTING AND PERFORMANCE EVALUATION OF AN INNOVATIVE INTERNAL PIPE SEALING SYSTEM FOR WASTEWATER MAIN REHABILITATION

by

John C. Matthews, Ph.D., Wendy Condit, P.E., and Ryan Stowe Battelle Memorial Institute Shaurav Alam, Ph.D. Louisiana Tech Trenchless Technology Center

EPA Contract No. EP-C-11-038 Task Order No. 01

Ariamalar Selvakumar, Ph.D., P.E. Task Order Manager

U.S. Environmental Protection Agency National Risk Management Research Laboratory Water Supply and Water Resources Division Urban Watershed Management Branch 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

January 2016

DISCLAIMER

The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development, funded and managed the research described herein under Task Order (TO) 01 of Contract No. EP-C-11038 to Battelle. It has been subjected to the Agency’s peer and administrative review and has been approved for publication. Any opinions expressed in this report are those of the 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. The quality of secondary data referenced in this document was not independently evaluated by EPA and Battelle.

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ABSTRACT

Many utilities are seeking emerging and innovative rehabilitation technologies to extend the service life of their infrastructure systems. This report describes the testing and performance evaluation of an internal pipe sealing system, which provides a permanent physical seal for the spot rehabilitation of cracks, leaks, corrosion, and other defects. The system tested was Pipe-Seal-Fix® from Pipe-Robo-Tec USA. The PipeSeal-Fix® system consists of a stainless steel sleeve and an ethylene propylene diene monomer (EPDM) rubber seal or gasket that span over a damaged spot in a sewer main. The sleeve and seal are installed together via a robotic closed circuit television (CCTV) camera and packer arrangement. The Pipe-SealFix® system is designed for use in storm and sanitary sewer pipe rehabilitation applications in diameter ranges of 8 to 24 inches (200 to 610 mm). Field demonstrations were attempted on a 10-inch sewer main in Santa Fe, Texas and an 8-inch sewer main in Baltimore, Maryland. Both locations had previously been lined with cured-in-place pipe (CIPP), but had significant defects allowing infiltration or exfiltration of the sewer flow. The system could not be installed at the Santa Fe, Texas location due to sagging and the ovality of the defective CIPP liner that prevented the system from reaching the repair site. The repair sleeve was successfully installed in Baltimore, Maryland. However, the repair was performed manually due to access issues that prevented the installation packer from moving through the pipe to the repair site. The post-lining inspection via CCTV showed the repaired section to be sealed, with no signs of exfiltration. The system was also tested via external hydraulic testing in the laboratory on three 8-inch steel pipes. The laboratory testing showed the seals were leak free for 2.5 hours above 15 pounds per square inch (psi), which is approximately twice the external hydraulic design pressure of 7.25 psi (0.5 bar). The material cost for the Baltimore, Maryland spot repair of an 8-inch sewer main was $756 and the installation occurred over approximately three hours. The project had a negligible carbon footprint as the equipment required for the installation was minimal. The technology shows promise as a low-cost and rapid trenchless repair approach. Access requirements should be assessed based upon site-specific conditions to ensure feasibility of the robotic-assisted installation, especially in previously lined pipes.

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ACKNOWLEDGMENTS

This report has been prepared with input from the research team, which includes Battelle and the Trenchless Technology Center (TTC) at Louisiana Tech University, and Dr. Ray Sterling. The technical direction and coordination for this project were 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 demonstration would not have been possible without the cooperation of the City of Baltimore. Cooperation from Pipe-Robo-Tec USA and others was crucial for this project and the authors would like to thank Luke Keenan and others from PipeRobo-Tec USA and the Savin Engineers field crew for their assistance on this project. Key contributors from the TTC included Ben Curry, Lane Elien, and Urso Adrian Campos for the experimental work.

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EXECUTIVE SUMMARY

Many utilities are seeking emerging and innovative rehabilitation technologies to extend the service life of their infrastructure systems. However, information on new technologies is not always readily available and not easy to obtain. To help to provide this information, the U.S. Environmental Protection Agency (EPA) developed an innovative technology demonstration program to evaluate technologies that have the potential to reduce costs and increase the effectiveness of the operation, maintenance, and renewal of aging water distribution and wastewater collection systems. The intent of this program is to make the technologies’ capabilities better known to the water and wastewater industries. This report describes the testing and performance evaluation of an internal pipe sealing system, which provides a permanent physical seal for the spot rehabilitation of cracks, leaks, corrosion, and other defects. The system tested was Pipe-Seal-Fix® from Pipe-Robo-Tec USA. This method is most applicable when only one or two defective areas require repair, while the remaining host pipe is in acceptable condition. The Pipe-Seal-Fix® system consists of a stainless steel sleeve and an ethylene propylene diene monomer (EPDM) rubber seal or gasket that span over a damaged spot in a sewer main. The sleeve and seal are installed together via a robotic closed circuit television (CCTV) camera and packer arrangement. The packer inflation forces the seal against the pipe wall and permanently locks the sleeve in place. The Pipe-Seal-Fix® system is designed for use in storm and sanitary sewer pipe rehabilitation applications in diameter ranges of 8 to 24 inches (200 to 610 mm). Field demonstrations were attempted on a 10-inch sewer main in Santa Fe, Texas and an 8-inch sewer main in Baltimore, Maryland. Both locations had previously been lined with cured-in-place pipe (CIPP), but had significant defects allowing infiltration or exfiltration of the sewer flow. The system was also tested in the laboratory on three 8-inch steel pipes to determine the maximum external water pressure it could withstand. The system could not be installed at the Santa Fe, Texas site due to sagging and the ovality of the defective CIPP liner. The system was successfully installed manually in the field at the Baltimore, Maryland site, but the robotic installation feature was not able to be fully demonstrated. The challenging pipe conditions leading to a manual installation included the pipe entering the manhole at eye level (i.e., a drop connection), plus the manhole was not a standard 48-inch diameter (i.e., it was only 28-inches in diameter). Despite these conditions, the post-lining inspection via CCTV showed the spot repaired section to be sealed, with no signs of exfiltration. These installations can only be confirmed visually, so laboratory testing was also conducted. The laboratory testing of three 8-inch steel pipes showed the seals were leak free for 2.5 hours above 15 pounds per square inch (psi), which is approximately twice the external hydraulic design pressure of 7.25 psi (0.5 bar). In terms of quality assurance/quality control (QA/QC) procedures, two post-installation checks were conducted including confirmation that the required inflation pressure was used on the packer and then a visual check with the CCTV camera of the overall position and fit. It is recommended that additional QA/QC measures be developed to ensure that the seal is properly installed. It would be advantageous to develop a field test for QA/QC to ensure that each seal is set and water tight. The material cost for the Baltimore installation was $756 for the spot repair of an 8-inch sewer main. The installation was completed in approximately three hours from site preparation to final CCTV inspection. The project had a negligible carbon footprint as the equipment required for the installation was minimal. The technology shows promise as a low-cost and rapid trenchless repair approach. However, access requirements should be assessed based upon site-specific conditions to ensure feasibility of the roboticassisted installation, especially in previously lined pipes. If possible, the initial CCTV inspection should be completed with the packer assembly and/or a simulated pig of similar dimensions to ensure that bends and offsets can be successfully navigated.

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TABLE OF CONTENTS

DISCLAIMER ............................................................................................................................................... i ABSTRACT.................................................................................................................................................. ii ACKNOWLEDGMENTS ........................................................................................................................... iii EXECUTIVE SUMMARY ......................................................................................................................... iv TABLE OF CONTENTS .............................................................................................................................. v ABBREVIATIONS AND ACRONYMS ................................................................................................... vii Section 1.0: INTRODUCTION .................................................................................................................... 1 1.1 Project Background............................................................................................................. 1 1.2 Project Objectives ............................................................................................................... 2 1.3 Report Outline..................................................................................................................... 2 Section 2.0: DEMONSTRATION APPROACH .......................................................................................... 3 2.1 General Approach ............................................................................................................... 3 2.2 Technology Selection Approach ......................................................................................... 5 2.2.1 Overview of Innovative Sewer Main Repair Approaches ..................................... 6 2.2.2 Overview of Internal Pipe Sealing System ............................................................ 6 2.2.3 Design of Internal Pipe Sealing System................................................................. 9 2.2.4 Installation of Internal Pipe Sealing System .......................................................... 9 2.2.5 QA/QC of Internal Pipe Sealing System ............................................................. 10 2.3 Site Selection Approach.................................................................................................... 11 2.3.1 Site Selection Factors........................................................................................... 11 2.3.2 Site Descriptions .................................................................................................. 12 Section 3.0: INTERNAL SEALING DEMONSTRATION AND TESTING ............................................ 13 3.1 Site 1: Santa Fe, Texas ...................................................................................................... 13 3.2 Site 2: Baltimore, Maryland.............................................................................................. 15 Section 4.0: DEMONSTRATION RESULTS ............................................................................................ 19 4.1 Technology Maturity ........................................................................................................ 19 4.2 Technology Feasibility ..................................................................................................... 19 4.3 Technology Complexity ................................................................................................... 19 4.4 Technology Performance .................................................................................................. 19 4.5 Technology Cost ............................................................................................................... 24 4.6 Technology Environmental Impact................................................................................... 25 Section 5.0: CONCLUSIONS AND RECOMMENDATIONS ................................................................. 27 Section 6.0: REFERENCES ....................................................................................................................... 29

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FIGURES Figure 2-1. Stainless Steel Sleeve and Rubber Gasket ................................................................................. 7 Figure 2-2. Schematic of Overall Locking Mechanism ................................................................................ 7 Figure 2-3. Detailed Photos of the Teeth, Locking Mechanism, and Hold-Down Plate............................... 8 Figure 2-4. Installation via a Robotic CCTV Camera and Installation Packer Assembly ........................... 9 Figure 2-5. CIPP Liner Failure at Santa Fe, Texas Site .............................................................................. 12 Figure 3-1. Site Preparation and CCTV Inspection .................................................................................... 13 Figure 3-2. Seal Preparation ....................................................................................................................... 13 Figure 3-3. Pipe-Seal-Fix® Placed on the Packer........................................................................................ 14 Figure 3-4. Robotic Camera ........................................................................................................................ 14 Figure 3-5. Upstream Manhole ................................................................................................................... 15 Figure 3-6. Initial CCTV Inspection ........................................................................................................... 16 Figure 3-7. Downstream Manhole .............................................................................................................. 17 Figure 3-8. Manual Inflation ....................................................................................................................... 17 Figure 3-9. Final CCTV Inspection of Seal Placement............................................................................... 18 Figure 4-1. Measurement Orientation (left) and Measurement (right) ....................................................... 20 Figure 4-2. Pipe-Seal-Fix® Sleeve with and without Elastomer Seal and Bladder System ........................ 20 Figure 4-3. Positioning of the Seal on the Sleeve (left) and Sleeve on the Bladder (right) ........................ 21 Figure 4-4. Positioning of the Bladder System Inside the Tube (left) and Rubber Seal from the Outside Prior to Inflation (right) ........................................................................................................... 21 Figure 4-5. Finished Sealing System from Inside (left) and from Outside (right) ...................................... 21 Figure 4-6. Test Setup – Positioning the Sample and Tube Inside a Larger Diameter Pipe ....................... 22 Figure 4-7. Testing of the Specimen ........................................................................................................... 22 Figure 4-8. Sample Prepared for the Capacity Test .................................................................................... 22 Figure 4-9. Change of Pressure Over Time during External Hydraulic Testing......................................... 23 Figure 4-10. Burst Pressure of the Specimen #2 ......................................................................................... 24 Figure 4-11. Capacity Testing of the Specimen (left) and Seal Broke at around 65 psi (right) .................. 24 Figure 4-12. Inputs for e-Calc for the Pipe Sealing Project in Baltimore ................................................... 25

TABLES Table 2-1. Framework of Technology Metrics to be Evaluated ................................................................... 4 Table 2-2. Selected Innovative Rehabilitation Technologies ....................................................................... 5 Table 2-3. Material Properties of Pipe-Seal-Fix® ......................................................................................... 6 Table 4-1. Measurement of the Annular Gaps ............................................................................................ 20 Table 4-2. Results from e-Calc for the Pipe Sealing Project ...................................................................... 26 Table 5-1. Technology Evaluation Metrics Conclusion ............................................................................. 27

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ABBREVIATIONS AND ACRONYMS

CCTV CIP CIPP

closed circuit television cast iron pipe cured-in-place pipe

DIP DIN

ductile iron pipe Deutsches Institut Für Normung (German National Standards)

EPA EPDM

United States Environmental Protection Agency ethylene propylene diene monomer

GFRP

glass fiber reinforced plastic

HDPE

high density polyethylene

NRMRL

National Risk Management Research Laboratory

psi PVC

pounds per square inch polyvinyl chloride

QA/QC QAPP

quality assurance/quality control Quality Assurance Project Plan

RCP

reinforced concrete pipe

SOT STREAMS

state-of-technology Scientific, Technical, Research, Engineering, and Modeling Support

TO TTC

task order Trenchless Technology Center

VCP

vitrified clay pipe

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Section 1.0: INTRODUCTION

1.1

Project Background

Many utilities are seeking emerging and innovative rehabilitation technologies to extend the service life of their infrastructure systems. However, information on new technologies is not always readily available and easy to obtain. To help to provide this information, research is being conducted as part of the U.S. Environmental Protection Agency’s (EPA’s) Innovation and Research for Water Infrastructure for the 21st Century research program to evaluate promising innovative technologies that can reduce costs and improve the effectiveness of the operation, maintenance, and renewal of aging drinking water distribution and wastewater collection systems. This research includes field demonstration studies of emerging and innovative rehabilitation technologies, which is intended to make the capability of these technologies better known to the water and wastewater industries. The specific technology metrics evaluated under this program include technology maturity, feasibility, complexity, performance, cost, and environmental impact. Several emerging and innovative technologies were identified by EPA based upon industry experience and extensive state-of-technology (SOT) reports (EPA, 2010a; 2010b; 2013). A successful demonstration project provides substantial value to utilities, manufacturers, technology developers, consultants, service providers, and contractors. The benefits of a technology demonstration program to these various groups are summarized below: Benefits to Utilities • Reduced risk of experimenting with new technologies and new materials on their own • Increased awareness of innovative and emerging technologies and their capabilities • Assistance in setting up strategic and tactical rehabilitation plans • Understanding of technology environmental impact and social cost • Identification of design and quality assurance/quality control (QA/QC) issues Benefits to Manufacturers/Technology Developers • Opportunity to advance technology development and commercialization • Opportunity to accelerate the adoption of new technologies in the U.S. • Opportunity to better understand the needs of utilities Benefits to Consultants • Opportunity to compare performance and cost of similar products in a consistent manner • Access to standards and specifications for new technologies • Education of best practices on pre- and post-installation procedures and testing Benefits to Contractors and Service Providers • Identification of successfully implemented QA/QC protocols • Identification of successfully implemented installation procedures including surface preparations • Understanding of regulations related to the use of new renewal technologies This report provides an assessment of the effectiveness, expected range of applications, and cost of the demonstrated technology to assist utilities in better decision-making on whether rehabilitation or replacement is more cost-effective in selecting rehabilitation technologies for use. The field demonstration described in this report resulted in the installation of an internal pipe sealing system for spot repair of an 8-inch wastewater collection main that had been previously lined with cured-in-place

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pipe (CIPP) in Baltimore, Maryland. The system was also pressure tested in the laboratory on three unlined, steel pipe test segments and all three held well above 15 pounds per square inch (psi). The activities involved with sealing system installation, which included pipe inspection, installation activities, and post-installation activities such as visual inspection and laboratory testing, are presented in this report. This report conducts a preliminary evaluation based upon both field and laboratory demonstration results. 1.2

Project Objectives

The project objectives are to: •

Evaluate, under laboratory and field conditions, the performance and cost of an innovative internal pipe sealing system used for spot repair of wastewater collection mains.

•

Document the results of the demonstration and testing, and provide recommendations related to product installation and QA/QC measures.

This research was conducted for the EPA National Risk Management Research Laboratory (NRMRL) under Task Order (TO) No. 01 titled Field Demonstration and Retrospective Evaluation of Rehabilitation Technologies for Wastewater Collection and Water Distribution Systems of the Scientific, Technical, Research, Engineering, and Modeling Support II (STREAMS II) Contract No. EP-C-11-038. The report describes data collection, analyses, and project documentation in accordance with EPA NRMRL’s Quality Assurance Project Plan (QAPP) Requirements for Measured Projects (EPA, 2008) and the project-specific QAPPs (Battelle, 2012) and QAPP Amendment (Battelle, 2015). 1.3

Report Outline

The report is organized into the following sections: •

Section 2.0 Demonstration Approach. Discussion of the demonstration program approach including an overview of the innovative rehabilitation technology.

•

Section 3.0 Internal Sealing Demonstration and Testing. Documentation of the field demonstration including site preparation, installation, and QA/QC procedures, as well as laboratory testing.

•

Section 4.0 Demonstration Results. Discussion of the demonstration results and assessment of the technology based on comparison with the outlined evaluation metrics.

•

Section 5.0 Conclusions and Recommendations. Summary of the demonstration including effectiveness of the demonstrated technology and recommendations for areas needing further examination.

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Section 2.0: DEMONSTRATION APPROACH

This section outlines the overall approach to the field demonstration and provides an overview of the innovative rehabilitation technology and site selection for this task. General Approach

2.1

The demonstration of innovative technologies requires clear and repeatable testing criteria if the technologies are to be understood and accepted. A protocol was developed to provide a consistent approach and a guide for conducting field demonstrations in a manner that encourages acceptance of the outcomes and results by wastewater utilities. The demonstration protocol addressed issues involved in gaining the approval for the use of innovative technologies by: • • •

Providing for independent verification of the claims of technology developers Sharing information about new technologies among peer user groups Supporting utilities and technology developers in bringing new products to a geographically and organizationally diverse market.

A QAPP was developed to outline the approach to plan, coordinate, and execute the field demonstration protocol with the specific objectives of evaluating, under field and laboratory conditions, the performance and cost of an innovative internal pipe sealing system for wastewater main rehabilitation. The QAPP described the overall objectives and approach to the EPA’s field demonstration program, the technology and site selection factors considered, and the features, capabilities, and limitations of the selected technology, which are summarized below (Battelle, 2012). The demonstration protocol was executed by completing the following steps: •

Prepared and obtained EPA approval for the QAPP;

•

Gathered relevant data for demonstration opportunities meeting the selection criteria;

•

Secured a commitment from the technology developer and contractor to use one of their projects as the demonstration study;

•

Documented and conducted the field demonstration as outlined in the demonstration protocol;

•

Processed and analyzed the results of the field demonstration and laboratory testing; and

•

Prepared a report and peer reviewed article summarizing the results.

This demonstration report not only records the use of the internal pipe sealing system technology, but also provides a documented case study of the technology selection process, QA/QC procedures, and the preparation for life-cycle management of the asset. In performing the field demonstration, the technical and QA/QC procedures specified in the QAPP were followed unless otherwise stated. Special aspects of the EPA demonstration program which were aimed at adding value to the wastewater rehabilitation industry are described below. •

Consistent Design Methodology. An important role of this task is to identify design parameters and specifications for the selected technologies and to document the application of a consistent design methodology based on the vendor recommendations or industry defined standards.

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•

QA/QC Procedures. The success of a rehabilitation project depends largely on proper installation controls and post-installation inspection and assessment. The level of qualification testing and QA requirements typically vary by technology without a clear quality standard. This task provided an opportunity to examine current QA practices and identify areas for improvement. For technologies lacking an industry quality standard, QA/QC procedures recommended by the vendor and utility should be reviewed and adopted (as appropriate).

•

Technology Range of Applications. The demonstration provides an assessment of the shortterm effectiveness and cost of the selected technologies in comparison with the respective vendor specifications and identifies conditions under which each technology can be best applied. This effort also provides suggestions on necessary improvements for the technology itself, the installation procedures, and QA/QC procedures. Several metrics that can be used to evaluate and document rehabilitation technology application, performance, and cost are identified (Table 2-1).

•

Life-Cycle Performance. Long-term performance data for rehabilitation systems is needed. These data will enable decision makers to make better cost-benefit decisions. This report will assist utilities in developing life-cycle plans for the ongoing evaluation of rehabilitation technology performance.

Table 2-1. Framework of Technology Metrics to be Evaluated Technology Maturity Metrics • • • • • • • • • • • • • • • • • • • •

Maturity is innovative (recently commercialized), emerging (not widely used in the U.S.), or conventional. Availability of supporting performance data and patent citation (if applicable). Comments and feedback from utility owners and consultants with experience from previous pilot studies. Technology Feasibility Metrics Applicability of the technology in meeting the rehabilitation requirements. Suitability of the technology to the operating conditions of the host pipe. Consideration of failure modes and documentation of design procedures. Technology Complexity Metrics Adaptability to and widespread benefit for small- to medium-sized utilities. Level of training required, pre- and post-installation requirements, and maintenance requirements. Time and labor requirements for the overall rehabilitation project. Evaluation of the installation process, procedures, and problems encountered. Documentation of the efficiency of the reinstatement of laterals, etc. Technology Performance Metrics Evaluation of manufacturer-stated performance versus actual performance. Expected visual appearance and geometric uniformity after installation. Ability to achieve design specifications. Ability to withstand typical sewer cleaning operations. Technology Cost Metrics Document costs including design, capital, operation and maintenance, traffic and surface footprint, and calculate a unit cost. Estimate an average level of social disruption (although social cost calculation is beyond the project scope). Technology Environmental and Social Metrics Assess utilization of chemicals or waste byproducts that have an unintended impact on the environment. Assess quantity of waste byproducts produced (e.g., wastewater volume, soil requiring off-site disposal). Evaluate the overall “carbon footprint” of the technology compared to open cut.

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2.2

Technology Selection Approach

Several emerging and innovative technologies were identified by EPA based upon industry experience and extensive SOT reports (EPA, 2010a; 2010b; 2013). From these resources, the Battelle team identified innovative technologies that have the potential to be demonstrated and that would provide a benefit to advance the SOT (see Table 2-2). This report focuses on the field demonstration of one of these technologies, Pipe-Seal-Fix®, which is an innovative robotic internal pipe sealing system for wastewater pipes. Table 2-2. Selected Innovative Rehabilitation Technologies Technology (Vendor) 3S Panels (National Liner)

GeoSpray™ (Milliken)

Pipe-Seal-Fix® (Pipe-Robo-Tec USA )

Melt-in-place pipe (Aqualiner)

Automated Leak Repair (Curapipe)

PipeArmor (Quest Inspar)

Technology Description Wastewater Rehabilitation Composite pipe consists of 3S segmental panels, host pipe, and 3S grout. Panels are made of transparent polyvinyl chloride, allowing visual confirmation of uniform grouting. Fiber reinforced geopolymer mortar designed for spray applications. Designed to adhere to the surface to build thickness. Internal pipe sealing system comprised of a stainless steel sleeve with a unique locking system and rubber gasket, which are described in Section 2.2.2. Water Main Rehabilitation Thin thermoplastic polymer composite liner for 6 inch to 12 inch diameters. Glass fiber reinforced polypropylene and a woven tube. Heated with a pig that melts the thermoplastic. Pig train contains curing substances under pressure that plug leaks as the pigs travel down the main. The substances harden to plug leaks. High build polyurea lining material that can be spray applied. Fast curing can potentially allow for fast return to service.

Rationale for Demonstration Circular or noncircular; visual confirmation of uniform grouting; used where bypassing is not feasible, large diameter.

Fast return to service; high durability; near-zero porosity; high resistance to acid; green material. Innovative internal pipe sealing system for spot repair. Includes robotic installation feature, which is described in Section 2.2.4. Performs as a Class IV liner capable of independently handling internal pressure and external loads.

Innovative technique for leak repair; can be deployed through hydrants.

Can be applied to a Class IV lining level capable of independently handling internal pressure and external loads.

The technology selection criteria identified by the project team follow the general guidelines below: •

Maturity. Novel and emerging technologies that are commercially available are desired. Technologies should be truly novel and more than an incremental improvement over conventional methods (EPA, 2009).

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•

Feasibility. The potential of the proposed technology as a compliance strategy for the sitespecific conditions should be identified. The nature of the problem faced in the pipe will ultimately drive technology selection.

•

Complexity. Technology adaptability to and widespread benefit for small- to medium-sized utilities is desired (EPA, 2009). The complexity refers to the level of training required for the installer, pre- and post-installation requirements, and maintenance requirements.

•

Performance. This criterion is evaluated based on the capabilities and limitations of the technology and investigation of potential advances over existing and competing technologies. Vendor performance claims will be compared to actual performance in the field.

•

Cost. The direct installation cost on a per-unit basis will be provided. Additional costs are sitespecific and may include pre-installation setup, pre-and post-installation inspection, cleaning, traffic control, and sewage bypass. Warranties or guarantees on performance should be provided.

•

Environmental. Technologies may use chemicals or produce waste byproducts that have an unintended impact on the environment or water quality. Technologies that reduce the overall carbon footprint of the project compared to open cut are desired (EPA, 2009).

2.2.1 Overview of Innovative Sewer Main Repair Approaches. Sewer main repairs are carried out to restore the sewer to an operating condition and to deal with localized deterioration. Typically, spot repairs will be made if there are only one or two sections requiring repair within a mainline segment, otherwise it may be advisable to replace or reline the entire segment from manhole to manhole. Open cut repair is the conventional approach used for spot repair of sewer mains where it is feasible and costeffective. Other repair approaches include external repair clamps and joint sleeves, cured-in-place pipe (CIPP) spot repair with short liners, and internal joint seals and mechanical spot repairs (EPA, 2010b). Battelle received an agreement from Pipe-Robo-Tec USA, which developed Pipe-Seal-Fix® (see Table 22), to participate in the EPA demonstration opportunity under this project. This repair technology, which is designed for gravity sanitary and storm sewers, is described below. 2.2.2 Overview of Internal Pipe Sealing System. Pipe-Robo-Tec USA’s Pipe-Seal-Fix® system is composed of a stainless steel sleeve and an ethylene propylene diene monomer (EPDM) rubber seal or gasket that span over a damaged spot in a sewer main (see Figure 2-1). The Pipe-Seal-Fix® system is designed for use in storm and sanitary sewer pipe repair applications in diameter ranges of 8 to 24 inches (200 to 610 mm). The physical properties for Pipe-Seal-Fix® are shown in Table 2-3. The materials used (i.e., stainless steel and rubber) have been verified to be corrosion resistant under sewer conditions (see Section 2.2.5). The stainless steel sleeve and elastomer seal are installed via a robotic closed circuit television (CCTV) camera and packer arrangement as described in Section 2.2.4. These seals can be installed quickly in low flow conditions, eliminating the need to bypass pump. The seals are also relatively easy to install and do not require highly specialized knowledge or equipment (Pipe-Robo-Tec, 2015). Table 2-3. Material Properties of Pipe-Seal-Fix® Property

Value 7.25 psi (0.5 bar) Stability up to 266oF

External Design Pressure Temperature Range

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Figure 2-1. Stainless Steel Sleeve and Rubber Gasket The AISI 316 L or 316 Ti stainless steel sleeve is used for its resistance to sewage conditions (see Section 2.2.5). The corrosion-resistant sleeve has a unique locking system that cannot unlock once expanded into place inside the pipe (see Figure 2-2 for an illustration and photo of the overall locking system). PipeSeal-Fix® does not require any curing; instead the packer used to expand the sleeve in place just needs to be pressurized to 40 psi to ensure the locks are fully expanded. The locking mechanism is described here briefly and in more detail in the Pipe-Seal-Fix® manual for additional information. There are two rows of teeth punched into each sleeve, which provide for two locks to hold the repair in place. The teeth help to guide the pinions (i.e., gears) of the locking mechanism. Detailed photos of the teeth, locking mechanism, and hold-down plate are shown in Figure 2-3. The locking mechanism consists of a pinion for guiding and a spring-loaded pinion for locking. The interlocking pinions are arranged so that the sleeve can only move in one direction for a forward expansion. After expansion of the seal, the spring element loses its function. The hold-down plate is there to uniformly press the expanding sleeve sheet and fixes the pinons in place (Pipe-Robo-Tec, 2015). The locking mechanism is made of titanium which had a high resistance to corrosion. The Pipe-Seal-Fix® system has been tested for corrosion resistance and high pressure flushing resistance as summarized in Section 2.2.5 below.

Figure 2-2.

Schematic of Overall Locking Mechanism (Courtesy of Pipe-Robo-Tec)

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Figure 2-3. Detailed Photos of the Teeth, Locking Mechanism, and Hold-Down Plate (From top to bottom; Courtesy of Pipe-Robo-Tec)

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Main Benefits Claimed • Addresses longitudinal and other cracks •

Reinforces pipe joints

•

Installed in non-accessible pipes

•

Adapts to nearly all pipe materials including reinforced concrete pipe (RCP), vitrified clay pipe (VCP), ductile iron pipe (DIP), cast iron pipe (CIP), glass fiber reinforced plastic (GFRP), polyvinyl chloride (PVC), and high density polyethylene (HDPE)

•

Installed quickly with minimal equipment

•

Trenchless process with minimal access requirements

Main Limitations Cited • Bends and offsets above 10% can cause difficulty as the sleeves are rigid •

Manholes must be large enough (> 30-inch diameter) to insert camera and packer equipment (typical manholes are 48-inches in diameter)

•

Temporary stoppage of flow or bypass may be required in high flow pipes

•

Proper access within the pipe is required and obstructions must be removed such as root penetrations

•

Temporary stoppage of flow or bypass may be required in high flow pipes

•

Not applicable to corrugated pipe and appropriate precautions must be taken to avoid cracking VCP.

Design of Internal Pipe Sealing System. There is no design standard for this technology. 2.2.3 The seals come in standard diameter ranges depending on the internal diameter of the host pipe to be repaired. Installation of Internal Pipe Sealing System. The Pipe-Seal-Fix® system is installed via a 2.2.4 robotic CCTV camera and installation packer assembly as shown in Figure 2-4. The robotic CCTV camera unit is outfitted with an adapter that connects it to a coupling rod that both moves and supplies compressed air to the installation packer unit.

Figure 2-4. Installation via a Robotic CCTV Camera (Left) and Installation Packer Assembly (Right) (Courtesy of Pipe-Robo-Tec)

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The following is a brief overview of the major steps involved in the application of the internal pipe seal: •

Conduct a pre-installation CCTV to assess that pipe conditions and access requirements are met

•

Remove any obstructions from the host pipe

•

Block and/or divert upstream flow in pipe (low flow allowable)

•

Inspect stainless steel sleeve for damage and remove all adhesive strips

•

Apply talcum powder to the inside of the EPDM rubber seal and slide seal over the sleeve

•

Cut rubber seal on each end with a sharp knife so the seal is 0.2 to 0.4 inches shorter than the sleeve

•

Adhere EPDM rubber seal to stainless steel sleeve using superglue applied to a maximum of four points at each end

•

Attach the installation packer to the robotic CCTV camera via a coupling rod

•

Position the Pipe-Seal-Fix® sleeve with the EPDM seal onto the installation packer

•

Rotate the sleeve on the installation packer so that the locking mechanism is at 12 o’clock and open the air valve just enough to hold the sleeve in position on the packer

•

Close the air valve and disconnect the coupling rod from the packer

•

Move the packer to the pipe entrance and then reattach the coupling rod and open the air valve. If the sleeve is flanged, the flanging must be installed in the direction opposite of the flow

•

Use the robotic CCTV camera to push the installation packer to the damaged section of the pipe

•

The sleeve and EPDM rubber seal should be positioned in the center of the damage

•

Build up pressure in the packer to the prescribed final contact pressure (40 psi for 8-inch sleeve)

•

Inspect installation using CCTV to determine if a re-tightening of the sleeve is needed

•

If the post-installation CCTV inspection reveals a misfit sleeve or other issues, the internal pipe sealing system can be removed, but it will be permanently destroyed in the process. The locking mechanism must be cut in order to remove the sleeve. This is accomplished with a milling robot equipped with a common flex disc for metals. Each lock is cut, which allows the EPDM rubber seal to contract and become loose so that the entire sealing system can be removed from the pipe (Pipe-Robo-Tec, 2015).

2.2.5 QA/QC of Internal Pipe Sealing System. The Pipe-Seal-Fix® system has been subjected to several laboratory-based QA/QC testing procedures as summarized below. The 50-year estimated design life is based upon the stainless steel and EPDM material testing. These tests are based on ASTM and German National Standards (or Deutsches Institut Für Normung [DIN]) and include: •

Testing the material identity of the elastomer sealants according to ASTM D5576;

•

Proving the steel quality as to its resistance to sewage water according to DIN 1986-3;

•

Testing high pressure flushing resistance according to DIN 19523;

•

Testing the water tightness for external pressure of 7.25 psi (0.5 bar);

10

•

Testing the water tightness under heavy load, deformation and bending according to DIN 4060

•

Drinking water test according to DIN DVGW W270; and

•

Elastomer directive of the German Federal Environment Agency (Pipe-Robo-Tec, 2015).

The field QA/QC regimen is less involved. Only a few visual QA/QC procedures are recommended by the manufacturer. First, the seal should be centered on the defect, which is confirmed visually with the CCTV camera. After full pressure has been applied (40 psi is recommend for an 8-inch sleeve), the sleeve is inspected via CCTV to ensure the locks have been expanded. However, this procedure is not optimal because the locks may not be able to open as wide on each end and it is difficult to see visually whether or not the sleeve can expand any more. This is why the minimum expansion pressure must be met. The main conclusion of this study is the need to improve field QA/QC procedures to ensure that a good seal is obtained, especially for CIPP lined pipes, pipes with significant ovality, and/or pipes with rough surfaces. In addition to the visual examination, it would be advisable to develop a means to inspect the seals to determine if there is a good fit (especially at either end of the seal). In addition, the ability of the packer to force the sleeve outward to make a tight seal between the sleeve and CIPP liner or between CIPP liner and pipe wall may need to be further studied. This would involve tests on various types of CIPP with various types of defects that are beyond the scope of this preliminary field demonstration. Site Selection Approach

2.3

To ensure that the field demonstration results are acceptable and useful to the user community, the field demonstration site and the condition of the selected test pipe had to be representative of typical applications for the internal seals. Therefore, the operational conditions (e.g., pipe type, structural integrity, etc.) and environmental conditions (i.e., subsurface conditions) of potential host sites had to be appropriate for the technology. Another important consideration in site selection was the wastewater utilities’ willingness to participate in the study. Site Selection Factors. Site selection was largely dependent on the utilities’ rehabilitation 2.3.1 needs, the availability of time and resources to contribute to the study, and a strong motivation to advance the state of emerging and innovative technologies. The following factors were considered in the site selection process for the demonstration program: •

Utility Commitment. Is the utility willing to use an emerging rehabilitation technology and to provide the required time and resource commitments to the project?

•

Perceived Value. What is the number of interested utility participants? Is the technology and/or test pipe rehabilitation need of national-scale versus regional-scale interest?

•

Regulatory/Stakeholder Climate. Are local/state officials willing to work with the utility concerning requirements to permit use of an emerging technique?

•

Test Pipe and Site Conditions. Are the test pipe operating and environmental site conditions suitable when compared to the technology’s application limitations?

•

Site Access and Safety. Are site conditions (i.e., site access, space requirements, etc.) suitable for a safe and secure field demonstration?

The site selection process for this demonstration involved employing a collaborative approach with the technology developer and installer in an effort to identify candidate sites for the planned demonstration study. As part of this process, a dialogue with Pipe-Robo-Tec USA was initiated and they indicated

11

multiple sites being planned for projects including Santa Fe, Texas and Baltimore, Maryland. The overall responsibilities of the technology vendor (Pipe-Robo-Tec USA) were defined as follows: • • • •

Provide vendor specifications, design, and installation information for the technology Provide the technology for evaluation during the field demonstration Provide equipment and labor needed for the duration of the demonstration Provide data from the field demonstration to verify performance and cost of the technology

2.3.2 Site Descriptions. Two field installation events of Pipe-Seal-Fix® were observed including a 10-inch pipe in the City of Santa Fe, Texas and an 8-inch VCP in Baltimore, Maryland. Both field sites had pipes that had been previously lined with CIPP that had defects requiring repair. The Santa Fe, Texas pipe was located 10 ft below ground surface and had a liner failure at the joint allowing a large volume of groundwater to infiltrate the pipe (see Figure 2-5). The Baltimore, Maryland pipe was an 8-inch VCP lined with 290 ft of CIPP, which had a defect near a downstream manhole that was allowing sanitary flow to exfiltrate the pipe. A CCTV scan of the defect was not available for the Baltimore site.

Figure 2-5. CIPP Liner Failure at Santa Fe, Texas Site (Courtesy of Pipe-Robo-Tec)

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Section 3.0: INTERNAL SEALING DEMONSTRATION AND TESTING This section outlines the activities involved with the Pipe-Seal-Fix® field demonstrations in Santa Fe, Texas and Baltimore, Maryland, including site preparation, technology application, and postdemonstration field verifications. 3.1

Site 1: Santa Fe, Texas

The first demonstration took place on April 22, 2015, in Santa Fe, Texas, on a 10-inch pipe that had previously been lined with CIPP, but ruptured at one location. Site preparation included placing a plug to minimize flow and the initial CCTV inspection. Battelle had one staff member in the field. Personal protective equipment included hard hats, safety glasses, steel-toed shoes, and safety vests. After arriving on site, the contractor placed the plug to allow for the CCTV inspection (Figure 3-1).

Figure 3-1. Site Preparation and CCTV Inspection Next, dye tests were conducted to determine if infiltration was taking place from any of the nearby laterals. No lateral defects were noted that required repair. The location of the liner failure was observed at 223 ft from the upstream manhole. However, the contractor subsequently decided to approach the repair of the CIPP liner defect from the downstream manhole due to jagged pieces of the failed liner near the upstream manhole. All equipment was moved to the next downstream manhole located at the intersection of 11th Street and Main Street. The rubber seal was slid on the metal locking sleeve and blue hydrophilic tape was put on the Pipe-Seal-Fix® to add increased sealing ability due to a slight misalignment in the pipe observed by the robotic camera (Figure 3-2).

Figure 3-2. Seal Preparation

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Next, the vacuum truck arrived and was prepared to water jet the line. After cleaning, the camera was lowered into the line and the liner failure was located at 223 ft upstream of the manhole. Next, the PipeSeal-Fix® was placed on the packer and secured by inflating the packer just enough to hold the seal in place. The packer was accidentally over-inflated causing the seal to expand to a diameter larger than the inner diameter of the pipe. A new seal was assembled and placed on the packer (Figure 3-3).

Figure 3-3. Pipe-Seal-Fix® Placed on the Packer The robotic camera was outfitted with an adapter that connected it to the push rod, which was connected to the packer (Figure 3-4). The packer with the seal was lowered into the manhole to be placed into the line. Due to the size of the original wheels on the packer, the seal would not fit into the pipe. The packer was raised up and smaller wheels were put on. The packer with the seal was then lowered back into the manhole and still did not fit. The pipe coming into the manhole was found to be non-circular, which prevented the seal from fitting into the pipe. The decision was made to try the repair from the next upstream manhole.

Figure 3-4. Robotic Camera

14

Pipe-Robo-Tec decided to try the same size (i.e., 10-inch) Pipe-Seal-Fix® without the hydrophilic tape and to also try a size smaller (i.e., 8-inch) Pipe-Seal-Fix®. Both sizes had to be picked up from their warehouse approximately 30 minutes from the site. Pipe-Robo-Tec returned to the site with an 8-inch and a 10-inch Pipe-Seal-Fix®. Prior to returning, the plug was removed. The backed-up water in the line caused the water level in the manhole to rise above the top of the pipe. Pumping upstream of the current location was started to lower the water level. Once the water level was low enough to allow entry into the manhole by personnel wearing hip waders, the 10-inch Pipe-Seal-Fix® without the hydrophilic tape was tried first. They were unable to fit the 10-inch Pipe-Seal-Fix® into the pipe due to a slight sag in the pipe that was not originally observed by the robotic camera. Next, the contractor attempted to insert the 8-inch Pipe-Seal-Fix®, but it was too small even when fully expanded. Finally, it was determined that due to the presence of the sagging CIPP liner and the contour/geometry of the pipe that Pipe-Seal-Fix® was not able to be used in this situation. The leak would have to be dug up and repaired at a later date. 3.2

Site 2: Baltimore, Maryland

The second demonstration took place on May 20, 2015 in Baltimore, Maryland on an 8-inch pipe that had previously been lined with CIPP, but failed at one location. The defect was approximately 4 inches in length and a 16.5-inch sleeve was installed for the repair. Site preparation included a CCTV inspection to locate the defect. Bypass pumping was not required as there was little flow in the main during installation. Traffic control was not required as the manholes were located in backyards. The demonstration took place over the course of approximately three hours from initial CCTV inspection to final CCTV check of the installation. Battelle had one staff member in the field. Personal protective equipment included hard hats, safety glasses, steel-toed shoes, and safety vests. A local crew from Savin Engineers was hired by the City to facilitate the sewer main inspection and repair process. Pipe-Robo-Tec supplied the Pipe-Seal-Fix® for Savin Engineers to install. The twoperson crew from Savin Engineers arrived on site at 8:00 am on May 20, 2015. Savin began by CCTV videoing from the upstream manhole (Figure 3-5) located in an open field in a backyard. The CCTV showed that the flow was not significant enough to require an upstream plug or bypass (Figure 3-6). From this initial location, the contractor videoed downstream 90 ft before encountering an offset in the pipe, which did not allow inspection to the defect that was located nearly 290 ft downstream. The contractor determined that an 8-inch camera and packer system would not fit through the offset to inspect the pipe and install the seal, which prevented the installation of the technology from the upstream manhole.

Figure 3-5. Upstream Manhole

15

Figure 3-6. Initial CCTV Inspection Savin moved to the downstream manhole, which was also located in a backyard (Figure 3-7, left). The manhole was 28 inches in diameter, which is smaller than a typical manhole (i.e., 48 inches in diameter) and the pipe was a drop connection (i.e., the pipe was not at the manhole bench, but approximately 4 ft above the bench). This made it difficult to launch the equipment from the surface since the installation packer was longer than 28 inches. Since the packer would not fit in the manhole, a tripod was set up above the manhole, which allowed the seal to be inserted manually and installed using a typical 4-inch plug (instead of the normal packer). This was only possible because the defect was within arm’s reach of the manhole (approximately 5 ft inside of the pipe). The vendor said this was the first time they had tried this type of install, but they were comfortable with the idea since the plug could expand the seal similar to the packer. There were two other small piped drop connections in the manhole, which made it difficult to maneuver while in the manhole. One was cutout and reattached after the installation. Since the plug expands like a balloon (round), it had to first expand on one end and then on the other end of the seal. The plug was manually placed at the downstream end of the seal (Figure 3-7, right) and slowly inflated to 20 psi from the surface with a portable air compressor. Then the installer from Savin got out of the manhole and the pressure was increased to 40 psi, which is the required pressure to expand the seal locks (Figure 3-8). The plug was repositioned at the upstream end of the seal and again slowly inflated to 20 psi. Again the laborer got out of the manhole and the pressure was increased to 43 psi, which is beyond the required pressure to expand the seal locks and the maximum pressure recommended for the plug being used. This entire installation took less than 30 minutes. After the seal was installed and the plug was removed, the flow coming out of the main increased significantly as the flow had previously been exiting the pipe through the defect.

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Figure 3-7. Downstream Manhole

Figure 3-8. Manual Inflation

17

The CCTV camera was re-launched to inspect the installation, which was deemed successful by the City representative and the installer based on visual evidence of stoppage of the exfiltration (Figure 3-9). A CCTV scan of the original defect was not available for the Baltimore site for comparison. Upon examination of the post-installation CCTV, it appeared as if the upstream end of the seal expanded slightly more than the downstream end. This could be due to the 3 psi difference in pressure used or a slight change in diameter in the host pipe. The installation took approximately three hours from site preparation through the final CCTV inspection.

Figure 3-9. Final CCTV Inspection of Seal Placement

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Section 4.0: DEMONSTRATION RESULTS

This section presents the results of the field demonstration and laboratory testing including an assessment of the technology based on the evaluation metrics defined in Section 2.1 and Table 2-1. The specific metrics that were used to evaluate and document the application of the Pipe-Seal-Fix® product for spot repair are described below. 4.1

Technology Maturity

While internal pipe seals are classified as conventional, the Pipe-Seal-Fix® system is classified as emerging in terms of maturity based on its design and use of the robotic installation method. The product was released on the U.S. market in January 2015 and has been applied at more than 10 sites. However, the results of those additional installations are not published. Representatives from the City of Baltimore were expected to use the product more in the future. 4.2

Technology Feasibility

The Pipe-Seal-Fix® system was designed to provide a permanent physical seal for the spot rehabilitation of cracks, leaks, corrosion, etc. While the robotic portion of the installation process could not be fully evaluated due to site-specific challenges, the system was found to be a viable option when remote access to the host pipe and defect is possible. Significant offsets that limit access of the CCTV camera and packer installation system can prevent the robotic installation of the pipe seal, but if the packer can fit, the installation can be completed. Other limitations include the need for flow bypass and removal of obstructions such as root penetrations. However, flow control was not required for the Baltimore demonstration due to low flow conditions, but typically some form of bypass or diversion would be required. 4.3

Technology Complexity

The internal pipe sealing process is not a complex procedure; therefore, it is conceivable that contractors or wastewater utility personnel could be trained to install this product. A typical two-person CCTV inspection crew could be trained to install the seals. The packer easily connects to a CCTV camera and the seal is loaded on the packer. If for some reason the seal was to be locked in place and needed to be removed, it would have to be cut out using a milling robot equipped with a common flex disc for metals. In terms of QA/QC, the only checks performed are that the required pressure is used on the packer and then a visual check is conducted with the CCTV camera to confirm position and fit. 4.4

Technology Performance

The technology performance was assessed in the laboratory through the ability of the seal to resist external hydrostatic pressure on three test pipes consisting of 8-inch diameter, unlined steel. The tests conducted did not simulate applying the sleeve over a defect in CIPP lined pipe, which could be a consideration for further study. Steel mechanical tubes were cut into 12-inch by 8-inch pieces. Later, the steel tubes were tack welded simulating a crack or defect that spanned the circumference of the pipe. The resulting gaps were measured around the circumference of the pipe using a Vernier Caliper (see Figure 41). The measured gaps are presented in Table 4-1. The annular gaps in the simulated defects were 0.25, 0.32, and 0.34 inches for pipes 1, 2, and 3, respectively. The Pipe-Seal-Flex® repair was then performed on each of the three pipes and subjected to external hydraulic testing up to 15 psi. In addition, one specimen was taken to failure to observe the maximum external pressure that could be withstood.

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Figure 4-1. Measurement Orientation (left) and Measurement (right) Table 4-1. Measurement of the Annular Gaps Specimen ID 1

(Pieces 1&2) 2 (Pieces 3&4) 3 (Pieces 5&6)

Gap at Different Clock Position (inch) 4 5 6 7 8 9

10

11

12

Average (inch)

0.27

0.20

0.23

0.21

0.25

0.34

0.34

0.33

0.33

0.32

0.32

0.33

0.40

0.41

0.31

0.35

0.34

1

2

3

0.19

0.22

0.27

0.29

0.29

0.29

0.23

0.25

0.30

0.29

0.29

0.30

0.32

0.33

0.33

0.31

0.37

0.34

0.38

0.29

0.30

0.31

Next, the annular gaps in each sample were sealed using the Pipe-Seal-Fix®. The Pipe-Seal-Fix® is a rolled stainless steel sleeve, containing an elastomer seal on the outer surface, which can be pressed and spanned over a damaged spot. The sleeve is expanded using a bladder system against the inside of the damaged pipe and locked in place (see Figure 4-2). The sleeve is manufactured in a way that the seal will permanently interlock within the defected pipe wall (see Section 2.2.2 for an explanation of the locking mechanism).

Figure 4-2. Pipe-Seal-Fix® Sleeve with and without Elastomer Seal and Bladder System

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The samples first were checked for any uneven sharp weld spots and removed where found using a handheld grinder or a file. This was necessary to protect the EPDM rubber seal surrounding the stainless steel sleeve. Next, the sleeve was outfitted with the rubber seal and positioned on the bladder system, which was then pushed inside the steel tubes and inflated at 43 psi (see Figures 4-3 through 4-5).

Figure 4-3. Positioning of the Seal on the Sleeve (left) and Sleeve on the Bladder (right)

Figure 4-4. Positioning of the Bladder System Inside the Tube (left) and Rubber Seal from the Outside Prior to Inflation (right)

Figure 4-5. Finished Sealing System from Inside (left) and from Outside (right) The tests were performed by applying external pressure on the outer surface of the samples. First, the samples were positioned inside a larger diameter pipe and both ends along the annular space were sealed 21

using circular inflatable tubes encapsulated using two steel plates (see Figures 4-6 and 4-7). Next, the annular space was filled with water and pressurized at 5 psi, 10 psi, and 15 psi for 30 minutes (see Figure 4-7) for each of the three specimens. In another test, one of the specimens was taken to failure. First, the specimen was positioned inside a steel pipe and two prepared steel washers were welded at both ends. The sample was then pressurized to reach its highest capacity (see Figure 4-8).

Figure 4-6. Test Setup – Positioning the Sample and Tube Inside a Larger Diameter Pipe

Figure 4-7. Testing of the Specimen

Figure 4-8. Sample Prepared for the Capacity Test Water pressure was applied on the specimens using the main supply line. The Pipe-Seal-Fix® specimens were found to hold 15 psi pressure (which is twice the design pressure) for approximately 150 minutes 22

each with no leaks observed. For Specimens #1 and #2, minor leaks were found around the inflatable tubes that were part of the testing apparatus, which were regulated by increasing the water supply pressure. No leaks were observed in the inflatable tubes for the Specimen #3 trial indicating optimization of the test setup (see the constant pressure achieved in Specimen 3 in Figure 4-9). Next, Specimen #2 was prepared for an external hydraulic test that would take the seal to failure conditions in order to determine the maximum external hydraulic pressure. The seal broke at approximately 65 psi, although they were designed for 7.25 psi (see Figures 4-10 and 4-11).

Figure 4-9. Change of Pressure Over Time during External Hydraulic Testing

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Figure 4-10. Burst Pressure of the Specimen #2

Figure 4-11. Capacity Testing of the Specimen (left) and Seal Broke at around 65 psi (right) 4.5

Technology Cost

The material cost was $756 for the 8-inch VCP spot repair in Baltimore, Maryland. This excludes equipment and labor. The cost to conduct a spot repair is dependent on a wide variety of variables. These common variables include: pipe diameter, length of pipe/number of repairs, the amount of cleaning and/or bypass required, and location of access points. Remote sites that require equipment and personnel to travel long distances can also impact pricing.

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4.6

Technology Environmental Impact

To estimate the carbon footprint, the tool known as e-Calc was used (Sihabbudin and Ariaratnam, 2009). The e-Calc inputs for the air compressor and CCTV truck are shown in Figure 4-12. The primary equipment was the air compressor which was used for less than one hour. The contractor also had the CCTV trucks mobilized for the day. Additional carbon impacts would be realized if cleaning and/or bypass pumping are required. However, in this field demonstration, an upstream plug or bypass pumping was not required due to the low flow conditions in the sewer main. The e-Calc outputs are shown in Table 4-2. The Baltimore project resulted in a carbon footprint of approximately 0.03 short tons (or 60 lbs) of CO2 equivalents from the use of the air compressor and CCTV truck. Because open cut repair is the conventional approach when feasible, the Pipe-Seal-Fix® footprint is compared to an equivalent open cut repair project, which would generate 2,000 lbs of CO2 equivalents per day based on previous studies (EPA, 2012).

Figure 4-12. Inputs for e-Calc for the Pipe Sealing Project in Baltimore

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Table 4-2. Results from e-Calc for the Pipe Sealing Project Category Equipment Porter Cable Air Compressor Transport CCTV Truck Total

HC (lbs) 0 HC (lbs) 0.03 0.03

CO (lbs) 0.01 CO (lbs) 0.13 0.14

Note: S/T is short ton, 2,000 lbs

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Emissions NOx PM (lbs) (lbs) 0.01 0 NOx PM (lbs) (lbs) 0.45 0.01 0.46 0.01

CO2 (S/T) 0 CO2 (S/T) 0.03 0.03

SOx (lbs) 0 SOx (lbs) 0.02 0.02

Section 5.0: CONCLUSIONS AND RECOMMENDATIONS

The laboratory evaluation of the internal pipe sealing system verified an external pressure of 15 psi was withstood with no leaks (approximately twice the design pressure of 7.25 psi) over 2.5 hours. The field demonstrations of the internal pipe sealing system encountered challenges associated with the robotic pipe installation methodology, which prevented the robotic installation aspect of the technology from being fully observed. The issues were primarily related to access issues for the packer system in CIPP lined pipes. In Santa Fe, Texas, the seal was not able to be installed due to access restrictions from a noncircular pipe due to sagging and/or ovality of the CIPP liner. In Baltimore, both an offset in the CIPPlined host pipe downstream and the limited size of the manhole upstream resulted in the need for the seal to be manually placed. Table 5-1 summarizes the overall conclusions for each metric used to evaluate the technology. In terms of QA/QC procedures, two post-installation checks are available including confirming that the required pressure is used on the packer and then a visual check with the CCTV camera of the overall position and fit. It is recommended that additional QA/QC measures be developed to ensure that the seal is properly installed. The field QA/QC measures should be improved to be more quantitative in nature and not rely solely upon visual observation. It would be advantageous to develop a field test to ensure that each seal is set and water tight. The technology shows promise as a low-cost and rapid trenchless repair approach. However, access requirements should be assessed based upon site-specific conditions to ensure feasibility of the robotic-assisted installation, especially in previously lined pipes. It is possible that the initial CCTV inspection should be completed with a packer or simulated pig of similar dimensions to ensure that bends and offsets can be successfully navigated. Table 5-1. Technology Evaluation Metrics Conclusion • • • • • • •

• •

Technology Maturity Metrics Emerging technology installed using robotic installation methodology. Corrosive resistance was not validated, but stainless steel has been proven. Some third-party data are available, but long-term testing is needed. Technology Feasibility Metrics One demonstration met the owner's expectation to eliminate exfiltration from the damaged area, while the other installation was not successfully installed. The seal was manually installed in one difficult to access pipe, but it could not be installed in the other difficult to access pipe. In both situations, installation via the robotic CCTV camera and packer arrangement was not achieved due to access issues in entering the pipe and/or within the pipe itself. The technology may face challenges in previously lined or rehabilitated pipes (e.g., CIPP) which reduce the inner diameter and may cause access issues. Careful review of design drawings, manhole sizes, and/or pre-installation CCTV may identify access issues ahead of time. However, some issues cannot be anticipated until the full CCTV and packer assembly is deployed in the field. Technology Complexity Metrics May be favorable in mainline segments with only one or two defects requiring repair, which would be more economical than a full-length liner depending on site-specific considerations. The process is not complex; therefore, contractors or utility personnel could be trained to install this product.

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Table 5-1. Technology Evaluation Metrics Conclusion (Continued) • • • •

• •

• • •

Technology Performance Metrics The post-lining inspection via CCTV showed the seal to be secure in place. Laboratory results showed the seals can withstand 15 psi for over two hours (approximately twice the design pressure of 7.25 psi). Ability to withstand typical sewer cleaning operations was not evaluated in this study, but has been addressed by the vendor through testing the seal’s high pressure flushing resistance according to DIN 19523 The durability of the individual repair versus a full length line is a factor to be considered, but has not been addressed in this preliminary technology evaluation. The technology is estimated to have a design life of 50 years based on manufacturer’s testing. Technology Cost Metrics The material cost was $756 for the Pipe-Seal-Fix® repair of the 8-inch VCP project. This includes cost for the sleeve and excludes costs for labor and equipment including site mobilization and pre- and postinstallation CCTV inspection. Specific costs for comparison to other spot repair technologies are not readily available (EPA, 2010b). It is likely to be faster and less expensive than a CIPP sleeve or carbon fiber–reinforced polymer (CFRP) wrap. Other mechanical joint seals are available on the market that may be comparable in terms of speed and costs. Technology Environmental and Social Metrics Social disruption was minimal since traffic control was not required. An estimated 60 lbs of CO2 equivalents were emitted from on-site operations. An open cut repair project, considered the conventional repair approach where feasible, would emit approximately 2,000 lbs of CO2 equivalents.

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Section 6.0: REFERENCES

Battelle. 2012. Quality Assurance Project Plan for the Demonstration of GeoTree Technologies GeoSpray™ Fiber Reinforced Geopolymer Spray Applied Mortar. October. Battelle. 2015. Quality Assurance Project Plan Amendment for Pipe-Robo-Tec Pipe-Seal-Fix®. May. Environmental Protection Agency (EPA). 2008. EPA NRMRL QAPP Requirements for Measurement Projects, U.S. EPA, Office of Environmental Information, Washington, D.C. Environmental Protection Agency (EPA). 2009. Rehabilitation of Wastewater Collection and Water Distribution Systems: White Paper. EPA/600/R-09/048, U.S. EPA, Office of Research and Development, Cincinnati, OH, May, 91 pp., http://nepis.epa.gov/Adobe/PDF/P10044GX.pdf. Environmental Protection Agency (EPA). 2010a. State of Technology Report for Force Main Rehabilitation. EPA/600/R-10/044, U.S. EPA, Office of Research and Development, Cincinnati, OH, Mar., 175 pp., http://nepis.epa.gov/Adobe/PDF/P100785F.pdf. Environmental Protection Agency (EPA). 2010b. State of Technology for Rehabilitation of Wastewater Collection Systems. EPA/600/R-10/078, U.S. EPA, Office of Research and Development, Cincinnati, OH, Jul., 325 pp., http://nepis.epa.gov/Adobe/PDF/P1008C45.pdf. Environmental Protection Agency (EPA). 2013. State of Technology for Rehabilitation of Water Distribution Systems. EPA/600/R-13/036. U.S. EPA, Office of Research and Development, Cincinnati, OH, Mar., 212 pp. http://nepis.epa.gov/Adobe/PDF/P100GDZH.pdf. Pipe-Robo-Tec USA. 2015. Pipe-Seal-Fix and Pipe-Seal-Flex Installation Manual. Available at http://www.piperobotecusa.com/assets/fix-flex_installation_manual_final.pdf. June. Sihabbudin, S. and S. Ariaratnam. 2009. “Methodology for estimating emissions in underground utility construction projects.” Journal of Engineering Design and Technology, 7(1), 37-64.

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