Baltimore City Department of Public Works (DPW) – Maryland, USA
City of Baltimore deploys acoustic optic fiber monitoring to avert potential pipe failure without the expense of excavating the entire line to find it.
Public utilities rarely make headline news unless an unexpected water main break shuts down a road or floods a neighborhood. Then the public swarms negatively all over the story.
In this instance, the opposite happened, and the public responded positively when the City of Baltimore Department of Public Works (DPW) announced that they had averted a “potentially disastrous water main break” in southwest Baltimore because of preemptive monitoring of the pipeline.
AFO hears “pings” on 16-foot segment
15 wire wrap breaks identified over 2-week period
$200,000 repair cost miniscule to the millions a catastrophic failure might have cost
The City of Baltimore Department of Public Works operates more than 7,000 miles of water and sewage mains.
In May 2017, analysts from Pure Technologies (Pure) notified DPW that something was wrong with a 16-foot segment of the Southwest Transmission Main that runs beneath Desoto Road (under the Interstate-95) and carries potable water for southwest portions of the City of Baltimore, Baltimore County, and portions of Anne Arundel and Howard Counties. Fortunately, this section of the 54-inch PCCP main was equipped with a SoundPrint® acoustic fiber optic (AFO) monitoring system, the outgrowth of a collaborative project between the city and Howard County in 2007.
The AFO system not only gave DPW an early warning of a distressed pipe section. It also offered them a cost-effective way to pinpoint a potential failure without the time and expense of excavating the entire line to find it.
Developed by Pure Technologies, the SoundPrint acoustic fiber optic monitoring technology is an industry leading system that tracks and records pipeline deterioration on prestressed concrete cylinder pipes (PCCP), the material of the pipe of which the Southwest Transmission Main was constructed.
Once installed in a pipeline, the SoundPrint AFO system remotely detects the acoustic signature of wire wrap breaks or “pings” and records their specific pipe location. If break activity increases, utility staff are alerted and can intervene on the deteriorating pipe in advance of a failure, much like DPW did with the Southwest Transmission Main.
Unlike electromagnetics, which identifies the number of wire breaks that exist at a point in time, acoustic monitoring identifies the number of wire breaks that occur during the monitoring period, effectively identifying the location of active deterioration for the lifespan of the asset.
In the case of Desoto Road, “our monitoring system reported an alarming 15 wire breaks over a two-week period, raising concerns of a failure and potentially catastrophic water main break,” DPW spokesman Jeffery Raymond said.
The “pings” from the snapped wire wraps, recorded by the acoustic monitors, set off alarm buttons at the Office of Asset Management formed by Public Works Director Rudy Chow.
“I created this office precisely to collect and utilize data that can help us stop problems before they happen,” explained Chow. “Our team moved quickly to prevent what could have been a disastrous water main break,”
The best option for fixing the pipe segment, it was determined, was to utilize high-strength tendon cables. The process called for excavating around the distressed section of pipe, then installing the tendon cables around the pipe’s circumference.
While the cost of repairs the Southwestern Transmission Main cost DPW $200,000, that amount is miniscule compared to the millions of dollars that unplanned emergency repairs can cost a utility. In this instance, an ongoing preventive maintenance program certainly did pay off for the agency.
As a footnote, repair of the Southwest Transmission Main project won the 2017 CEAM Small Project of the Year Award for the City of Baltimore.
“Our monitoring system reported an alarming 15 wire breaks over a two-week period, raising concerns of a failure and potentially catastrophic water main break.”Jeffery Raymond