WERF Releases Force Main Inspection Study

By Jeff Griffin, Senior Editor | April 2012, Vol. 67 No. 4
Walter Graf.

Pressurized force mains represent a relatively small percentage of the nation’s wastewater collection infrastructure, but are essential in many systems to move waste where gravity isn’t sufficient to sustain flow. Failure in a force main segment can cause major disruptions in service with costly operational and environmental consequences.

Historically, wastewater system operators have found it difficult to take a pro-active approach to force main maintenance because accessing buried pipes is difficult and costly and the use of conventional closed circuit television (CCTV) inspection equipment usually means the system must be shut down which requires a bypass system.

WERF -- the Water Environment Research Foundation -- has developed a study, Inspection Guidelines for Wastewater Force Mains that covers the latest methods and technologies for inspecting force mains and provides practical guidance for system operators in addressing this important task.

“A part of any asset management program is knowing the current state of your assets,” observes Walter Graf, WERF program director for asset management. “Condition assessment is one part of determining the remaining life of an asset and this report is the first effort to examine inspection methods particular to these pipes. Although representing a small percentage of buried wastewater infrastructure, force main failure can have greater consequences than those of gravity lines.”

Graf said information in the Inspection Guidelines for Wastewater Force Mains report supplements the extensive information in WERF’s web-based asset management knowledge base SIMPLE (Sustainable Infrastructure Management Program Learning Environment).

The force main report is available free of charge to WERF subscribers. It is available to the public in pdf format for $50.

Report specifics
The report was prepared for WERF by Jason Consultants. Principal investigator was James C. Thomson, C.Eng (chartered engineer). Authors are Thomson, Robert S. Morrison, P.E. and Tom Sangster, C. Eng., MBA.

Authors of the 370-page report note that it is well established from surveys, questionnaires and direct experience that very little or no assessment and inspection of force mains is being undertaken.