Practical Application of Force Main Condition Assessment Methodologies for Long Term Asset Management Needs

Condition assessment is a foundation of a long term asset management program. However, it can also be logistically difficult, inherently subjective, and at times, even cost prohibitive. This is especially true when dealing with pressurized infrastructure including wastewater force mains. In order to be successful, each project requires a thorough understanding of available methods and technologies; the physical attributes of the collection and conveyance system; its operating parameters; and close coordination with the Owner's engineering and operations staff. One proposed, and cost-effective condition assessment program approach includes a strategic combination of traditional and innovative inspection methods. Operations include field corrosion evaluations such as soil corrosion studies, discrete pipe wall thickness inspections, and corrosion pitting analyses. Other non-destructive methods include the internal deployment of Remote Field Eddy Current (RFEC) and/or Acoustic Leak Detection (ALD) inspection technologies to determine continuous pipe wall thicknesses or to detect the presence of active leaks and air pockets of potentially corrosive gases. This paper will describe the practical development of a wastewater force main evaluation program including the approach; selection and implementation of inspection methodologies; identification of specific challenges and alternatives; and the presentation of a case study from an on-going evaluation program including inspection results, data analysis, and lessons learned.