State of Technology Report for Force Main Rehabilitation, Final ...

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Failure Records Structural Emergency Costs Structural Defects Material Defects 3 rd Party Damage Repair maintenance Direct Cost Repair Size Location Predicted Risk of Structural Failure Installation Defects Age Wire Design Cylinder Material 51 Pressure Mortar Operational Location Figure 4-3. Belief Network for Risk of Failure in PCCP Diversion Soil Consequences Health/Environment Health Flooding Traffic Damage claims Inspection Data Socio-Economic Figure 4-4. Belief Network for Consequences of Failure in PCCP 3 rd Party Claims
5.0 DESIGN AND QA/QC This section will review the existing design concepts that pertain to the renewal of a force main. The design methods currently employed are for either interactive or independent liners and depend upon the condition of the existing (host) pipe. A complete review of most applicable ASTM standards is included. These standards are broken down by material type and functionality including product/material, design, and installation practices. The section also covers the QA/QC aspects of renewal by looking at short-term factory and field requirements, as well as long-term qualification requirements. The latter are notably lacking for many products offered for both a pressurized and corrosive environment. 5.1 System Design 5.1.1 Redundancy in System Design. Force mains are often located at critical points in a utility’s sewerage system. They typically carry a large percentage of a utility’s untreated wastewater and in a few cases all of the flow to the wastewater treatment plant is conveyed through force mains. Despite the critical nature of sewer force mains, less than 5% have any redundancy built into the system (WERF, 2009). The use of redundancy in system design appears to be a more frequent practice in Europe than the US. If a line is taken out of service due to a failure, by-pass pumping or the use of honey trucks is necessary. Those that do have a redundant line can use it during a failure to maintain a minimal level of flow, avoiding overflowing wetwells, and surcharging upstream sewers. The other advantage to having a redundant line is the ability to take a force main out of service for an extended period of time to allow for either an intrusive (internal) inspection or for extended repairs or rehabilitation. With redundancy very limited, most utilities have not been in a position to carry out in-depth inspections and assessments of their force main systems. Consequently, many utilities in the past have merely reacted to problems, such as failures, when they occur rather than being proactive in attempting to assess the force main’s in situ condition. Little is known about the condition of sewer force mains in US utilities, but that is gradually changing, primarily as a result of EPA consent decrees requiring municipalities to carry out condition assessment of their force mains. Heretofore, there has been very little rehabilitation of sewer force mains due to lack of redundancy and the availability of reconstruction products for pressure sewers. The redundancy issue isn’t going to change overnight, although more utilities are considering investing in redundancy with new projects. Any attempt to rehabilitate a sewer force main, aside from outright replacement while the main remains in service, is going to either require by-pass pumping or a renovation technology that can be installed very quickly during a limited outage. The latter doesn’t exist at the moment so by-pass pumping is the norm. As a result of vendor success in the gravity field with CIPP and reformable thermoplastic pipe products, adaptations of these products are now starting to find their way into the pressure sewer field. 5.1.2 Pig Launchers/Retrieval for Cleaning and Inspection. Like redundancy, pig launchers and retrieval systems are not commonly designed into sewer force mains. Some utilities, like St. Petersburg, FL, have installed pig launchers and retrievals on most of their sewer force mains and use them on a regularly scheduled basis to clean each main. Keeping the mains clean maintains capacity and reduces pumping (energy) requirements. It is only within the past few years that some leak detection tools have become available to allow for limited assessment of a force main with little interruption in service. These tools can be introduced into the flow stream and are either tethered (Sahara ® ) or free swimming (SmartBall ® ) and will locate leaks and gas pockets in a force main. These tools can be launched through 2 inches (50 mm) (Sahara ® ) or 4 inches 52
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EPA/600/R-10/044| March 2010 | www.
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DISCLAIMER The work reported in thi
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Introduction EXECUTIVE SUMMARY Forc
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The use of close-fit liners is ofte
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A whole host of ASTM specifications
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CONTENTS DISCLAIMER ...............
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6.0: OPERATION AND MAINTENANCE.....
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DEFINITIONS Cured-in-place pipe (CI
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3-D three-dimensional AASHTO ACP AR
Page 19 and 20: UV ultraviolet WERF Water Environme
Page 21 and 22: wastewater conveyance systems (EPA,
Page 23 and 24: • Section 8: Findings and Recomme
Page 25 and 26: Figure 2-2. Diameter Distribution o
Page 27 and 28: Figure 2-4. Location of Force Mains
Page 29 and 30: Proper inspection of force mains wo
Page 31 and 32: 0.03% of the overall length. There
Page 33 and 34: Table 3-1. Summary of Renewal Techn
Page 35 and 36: 3.3.3 Joint Repair 3.3.3.1 Internal
Page 37 and 38: more appropriate to a water main wh
Page 39 and 40: are, however, several communities (
Page 41 and 42: Table 3-3. Properties of Hunting Po
Page 43 and 44: 3.4.3.1 Symmetrical Reduction Close
Page 45 and 46: Rolldown Rolldown was developed in
Page 47 and 48: Subline Subline, offered by Subterr
Page 49 and 50: On-Site Expandable PVC Close-Fit Li
Page 51 and 52: 3.4.4.2 Semi-Structural CIPP Liners
Page 53 and 54: inch (150 mm) liner down to 60 psi
Page 55 and 56: 3.4.5.1 Adhesive-Backed Woven Hose
Page 57 and 58: US. Primus Line is a seamless, wove
Page 59 and 60: Figure 3-21. Summary of Replacement
Page 61 and 62: favorable to stringing out a long l
Page 63 and 64: 3.5.1.3 Pipe Slitting. Pipe slittin
Page 65 and 66: 4.1 4.0 TECHNOLOGY SELECTION CONSID
Page 67 and 68: head loss to maintain flow capacity
Page 69: ferrous main, this can be an intern
Page 73 and 74: thickness? It can still support the
Page 75 and 76: pipe’s design life. Once again, i
Page 77 and 78: ASTM F1533 The renewal process invo
Page 79 and 80: AWWA M55 PE Pipe - Design and Insta
Page 81 and 82: Most of the controversy over the ap
Page 83 and 84: up to each individual manufacturer.
Page 85 and 86: For pressure applications, a hydros
Page 87 and 88: Dimensional checks on the pipe diam
Page 89 and 90: 5.6.2.3 CIPP Long-Term QA/QC Requir
Page 91 and 92: Figure 6-1. Polyurethane Pipeline C
Page 93 and 94: in currents or potentials indicate
Page 95 and 96: could also be used in force mains.
Page 97 and 98: 7.0 GAPS BETWEEN NEEDS AND AVAILABL
Page 99 and 100: 80 Table 7-1. Technology Gaps and C
Page 101 and 102: 82 Table 8-1. Parameters for Evalua
Page 103 and 104: 8.5 Sound, Risk-Based, Decision-Mak
Page 105 and 106: 9.0 REFERENCES Aggarwal, S.C. and M
Page 107 and 108: Technology/Method Spray - On Lining
Page 109 and 110: Technology/Method Spray - On Lining
Page 111 and 112: Technology/Method Spray - on Lining
Page 113 and 114: Technology/Method Close Fit/Tension
Page 115 and 116: Technology/Method Close Fit PE/Symm
Page 117 and 118: Technology/Method Symmetrical Reduc
Page 119 and 120: Technology/Method Rolldown/Close Fi
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Technology/Method Subcoil/Close Fit
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Technology/Method PE Liner/ Cement
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Technology/Method Subline/Close Fit
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Technology/Method Fold and Form PE
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Technology/Method Fold -and - Form/
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Technology/Method Fold -and - Form/
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Technology/Method Fold -and - Form
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Technology/Method Fold -and - Form
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Technology/Method Close - Fit Linin
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Technology/Method CIPP/Pull In Plac
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Technology/Method CIPP/Inversion wi
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Technology/Method CIPP/Direct Inver
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Technology/Method CIPP/ Inversion a
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Technology/Method CIPP/Glass Fiber
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Technology/Method CIPP/Pull in Plac
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Technology/Method CIPP/UV Light Cur
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Technology/Method CIPP/Glass Reinfo
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Technology/Method CIPP with Carbon
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for Rehabilitated Sections V. Costs
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Technology/Method Woven Hose Lining
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Technology/Method Saertex - Liner®
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Technology/Method Hose Liner/Pulled
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Technology/Method Glass Reinforced
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Technology/Method Sliplining/HDD/Pi
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