C-Factor Testing as a Condition Assessment Tool for Wastewater Force Mains

This paper presents the key findings of the use of C-factor testing as a condition assessment tool for more than 20 wastewater force mains in terms of existing condition and projected useful life. The efficient and effective operation of sanitary sewer lift and pump stations and force mains is critical in the overall operation of many sanitary districts in the United States. Many times, the actual operation of these hydraulic facilities is very different from the original design intent. C-factor testing is a quick, minimally invasive means of determining the actual flow rate, pressure, and friction loss through the station piping and force main system. If the operation of the system has been changed or the amount of flow has increased or decreased, this may have a dramatic impact on the operation of the facility from an efficiency point of view. This paper presents the results of more than 20 actual field measurements of C factors on existing sanitary sewer system force mains and the findings in terms of pump efficiency, amount of debris in the force mains, and the general operating conditions of the stations. The paper presents how this tool can assist owners in managing their systems for longer operational service lives.