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

8.0 FINDINGS AND RECOMMENDATIONS
Partly because of the difficulty in assessing the condition of sewer force mains, leaving a lot of
owners with questions about the integrity of these critical assets, and the limited amount of
rehabilitation technologies available for renewing a deteriorated main, there has not been a significant
amount of renewal work in the past. Most of the renewal activity has been outright replacement of the
force main, either by open cut or trenchless means. As the nation’s force mains age further, greater
emphasis will be placed on finding cost-effective ways to renew these critical assets. Fortunately,
new products and technologies are now emerging for carrying out a direct condition assessment on a
buried force main, as well as rehabilitation methods for those found in distress. Many of these
rehabilitation methods originated in the gravity sewer market or water market, but have been adapted
to meet the special needs of sewer force mains.
One method of assisting owners in their efforts to apply some of these emerging technologies will be
in the publication of demonstration projects and case studies. Also, setting up a decision support
system that helps a utility ask the right questions so that a viable rehabilitation solution emerges is
paramount. Utilities also need to consider implementing maintenance programs that can
demonstratively extend the useful life of their current mains, deferring the cost of renewal or
replacement to a future date.
This section reviews a number of these subjects and offers suggestions for technologies that might be
considered in some demonstration projects.
8.1 What Systems Would Benefit Most from Being Demonstrated in Field Settings?
Systems that would benefit from demonstration in field settings fall into two categories: data
collection (inspection) systems and rehabilitation systems. The scope of this review is rehabilitation
rather than inspection. Nevertheless, the demonstration of certain inspection systems was considered
to be valuable because they can provide data that drive rehabilitation decisions. Referring to Table 7­
1, the technologies for which field demonstration would yield greatest benefit would be the following:
• External data collection: Screening method to identify high risk locations. Potentially
LPR or over line potential surveys.
• Internal data collection: Live insertion and retrieval of inspection tool. Pipe Diver (PPIC,
Canada) for PCCP and See Snake for ferrous mains.
• Internal data collection: Acoustic technologies for leak detection and location of air
pockets. Sahara ® (PPIC, Canada) and SmartBall ® (Pure Technologies, Canada).
• Internal lining: CIPP (nonwoven felt/polyester resin and woven fiberglass/UV-cured);
sliplining (PVC and HDPE); and close-fit lining (PVC and HDPE).
• Structural spray-on lining with fast cure: polyurea-based material.
8.2 Key Parameters for Evaluation in Demonstration Projects
Table 8-1 identifies the key parameters to be evaluated in demonstration projects.
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