Getting Smarter About Your Force Mains - What You Don’t Know Could Scare You


  • William (Bill) Orne PE - Hazen and Sawyer
  • Mike Jacobson - Pure Technologies

There is an ever growing problem with aging and failing infrastructure that leads to unexpected capital cost, environmental impacts, regulatory issues and customer service interruptions to name a few. As new pipeline assessment technologies become available, utilities have more useful tools and processes to proactively assess asset condition and plan for renewal and replacement before it becomes an emergency. ReWa has hired Hazen and Sawyer to develop a force main condition assessment program and effectively analyze force main condition with appropriate technology. The force main condition assessment was divided into two phases with the first phase being the risk analysis for all force mains. The second phase was the implementation of the inspection technologies to assess force main conditions.

The risk based analysis was developed with key criteria and associated weighting to identify “at-risk” areas of the force main. The result of the analysis ranked each force main segment and individual piping components based on risk. This method allowed us to identify the most critical force main segments within the system for further inspection and assessment.

A review of currently available condition assessment techniques was made to determine what technology would be most beneficial for each of the critical force main segments. The initial assessment for two of the force mains was made with Pure Technologies’ SmartBall Pipe Wall Assessment (PWA) inspection technology. SmartBall is a free-flowing, in-line inspection platform that can be inserted into pressure pipelines under operating conditions. The tool is inserted into a pipeline and travels with the flow for up to twelve hours while collecting acoustic and PWA data. SmartBall requires only two access points for insertion and extraction, and is tracked throughout the inspection at predetermined fixed locations on the pipeline.

The SmartBall tool is able to acoustically detect the presence and location of leaks and gas pockets. For force mains, gas pockets are of particular concern because they can result in internal hydrogen sulfide corrosion of pipe surface. PWA technology collects data by measuring changes in the self-generated magnetic field produced by ferromagnetic materials in stress. SmartBall PWA is a detailed screening technology used for assessing the condition of metallic pipelines by identifying pipe sections (joint-to-joint) which exhibit increased levels of stress.

The project required planning, coordination, and communication between the Utility Engineering and Operations Staff, Consultant, and technology provider. The presentation will focus on the analysis needed to identify the force mains for inspection; the selection of inspection technologies; the level of planning required to implement the testing; and the results of the completed testing.

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