Optimizing Pipeline Rehabilitation Programs
In 2014, New Jersey American Water embarked on a pilot project that would soon transform its methodology for pipeline rehabilitation. The utility, which serves a population of nearly 3 million, tested an acoustic-based technology that enabled it to perform a non-intrusive condition assessment of several stretches of its pit cast-iron mains. The results of that pilot project were profound and changed the way the utility reviewed and determined its strategies for cleaning and lining (C&L) rehabilitation.
Pilot Project Outcomes
With more than half of New Jersey American Water’s distribution system installed before the 1960s, it was imperative for the utility to collect accurate data about the true condition of its pipes in order to determine the best course of action for rehabilitation. The impetus for piloting the new technology was a disruptive and costly break of one particular rehabilitated water main, which had recently been cleaned and lined. Prior to the use of ePulse® acoustic-based testing, New Jersey American Water would determine which mains to rehab by looking at typical fire flows, the number of breaks recorded, type of pipe, and other historic data. It would then clean and line the targeted pipes without a complete understanding of the remaining service life (RSL).
“What we had found was that many times when you rehab the pipe, the tuberculation inside the pipe is primarily what’s holding it together,” said Michael Wolan, Engineering Manager for New Jersey American Water. “The graphitization of the pipe was not something that we were able to determine by our other methods, so the pipe may have been past its useful life or getting near to it when we went in to clean and line it.”
In order to better accurately determine the structural integrity of its aging pipelines and the methods for addressing them, New Jersey American Water has since integrated ePulse® to its methodology toolbox and now uses it annually. This has improved how the utility estimates the number of useful years left in its pipe segments, enabling Wolan and his team to make more educated decisions about its pipeline rehabilitation programming. “It’s giving us more data and more data is always good for making effective decisions,” Wolan said.
Integrating into the Program
Developed by us, ePulse® is a non-intrusive, non-disruptive method for assessing the conditions of water mains through the use of acoustic sensors. Without taking pipelines out of service, ePulse® can collect data that indicates the average minimum wall thickness of targeted pipe segments, as well as check for leaks in the distribution system. This information is then used by utilities for addressing water distribution problems through rehabilitation or replacement methods. Rehabilitation is the most ideal, as it minimizes disruption to customers and extends the life of existing pipe assets while improving water quality and flows.
Since the initial 2014 pilot project, which tested pit cast iron pipeline segments between 4 to 12 inches in diameter in the state’s Millburn and Maplewood areas, New Jersey American Water has deployed the acoustic-based testing in the West Orange, Westfield, Clark, Maplewood, Chatham, North Plainfield, and Hillside communities. The utility now mandates that any pipeline marked for rehabilitation be tested with ePulse® prior to determining the lining methods for the project. New Jersey American Water does two types of lining for its cast-iron mains, polyurea-based and cement mortar.
“We primarily try to have the acoustic condition assessment testing performed either in the fall of the previous year or in the early months of the year,” Wolan said. “For example, if you look at the 2017 season for rehabilitation; cleaning and lining generally starts around April and ends by the end of October.”
New Jersey American Water periodically verifies its acoustic testing results by also sending out metallurgical samples for testing. During the pilot project in 2014, the utility had wanted to verify that the areas ePulse® identified as structurally deficient were indeed such. The physical pipe samples proved to align with the data collected by us, and the utility continues to find similar results today.
A Valuable Program Tool
Currently, New Jersey American Water employs acoustic-based testing for its cast-iron pipes, and recently performed a first pilot of transite (asbestos cement, or AC) pipe testing in its coastal north section district. Similar to the cast iron validation testing, coupons will be taken to verify our results. The technology has performed well with AC pipelines in other cities, according to John Marciszewski, Echologics® Director of Business Development, and its results have matched up with the results of phenolphthalein dye tests that reveal remaining structural thickness.
Since the 2014 pilot, which tested roughly about 20,000 feet of cast iron mains, the utility has tested a further 200,000 feet in New Jersey American Water’s North delivery area, and 100,000 feet in the South delivery area, said Marciszewski. The utility now tests generally between 50,000 and 80,000 feet of pipe segments in any given year.
Wolan said the utility still very much uses the RSL data gathered via other methods in its toolbox, but the integration of ePulse® acoustic-based testing has proven to be valuable. “We are using it broadly now in our rehabilitation methodology for determining the type of liner we use, and we’re very satisfied with the results we have been getting,” he said of our technology. “We do tend to put our toes in the water carefully, like with the pilot, but once we’re convinced that the technology has value to the company, our customers, and our stakeholders, then it’s a technology that we’re willing to embrace and use on a broad basis.”
NJAW now mandates that any pipeline marked for rehabilitation be tested with ePulse® prior to determining the lining methods for the product.