Service: SmartBall Leak Detection
Client: Birmingham Water Works Board
Project Date: January 2012 - ongoing
Location: Birmingham, Ala
Type of Pipeline: Water Transmission Main
Diameter: 42-inch (1050mm)
Pipe Material: Reinforced Concrete Pipe
In early 2012, the Birmingham Water Works Board (BWWB) ran a successful leak detection program on 7.7 miles (12 km) of 42-inch (1050-mm) Reinforced Concrete Pipe (RCP). The inspected pipelines are part of BWW’s system that transports water from the Shades Mountain Filter Plant to different areas of the city. The inspected pipeline was constructed in 1927 and has a typical operating pressure between 60 and 90 psi. BWWB completed the inspection to proactively address water loss on its large-diameter water transmission mains.
Although leaks on small-diameter distribution pipelines are the most common form of leak a utility encounters, leaks on large-diameter transmission pipelines are of greater importance in maintaining safe and reliable service delivery. Because large-diameter leaks are less common, they often go undetected for long periods of time resulting is massive water losses.
A study completed by The American Water Works Association showed that while leaks on large-diameter pipelines make up less than 5 percent of the total number of leaks, they account for more than 50 percent of the total water lost from leaks. This is primarily because transmission mains carry water at a much higher capacity and operating pressure than distribution pipelines. By focusing leak detection programs on large pipes, a utility can achieve a large reduction in Non-Revenue Water by identifying and repairing even one leak on a major pipeline.
BWWB completed the inspections in order to proactively address leakage on its critical large-diameter pipelines, as well as identify and repair suspected leaks on the 42-inch (1050-mm) pipeline.
Results at a Glance
- SmartBall leak detection located 26 leaks in 7.7 miles of inspection
- 20 leaks have been verified and repaired by BWWB
- Leaks as small as ~1 gallon per minute idetified by SmartBall technology
What was the Solution?
In many cases, an infrastructure management program that addresses leaks on large-diameter water transmission mains is the first step to an overall infrastructure renewal plan. Early identification and repair of leaks allows utilities to reduce lost revenue and prevent pipeline failures, as leaks are often an early signal that a pipeline will eventually rupture. Completing regular leak detection surveys also provides important information about the baseline condition of a pipeline and can act as a prescreening function in determining a more comprehensive condition assessment plan.
In order to ensure a successful project, BWWB planned the project thoroughly in order to achieve optimal conditions for the technology. This included review of drawings and flow management, as well as strong communication with the consulting leak detection firm, Pure Technologies.
BWWB used SmartBall leak detection for the inspections. The tool is a free-flowing leak detection platform that operates while the pipeline remains in service. It is capable of completing long inspections in a single deployment and is equipped with an acoustic sensor that identifies acoustic anomalies associated with leaks; the acoustic signature is then analyzed to determine if it is a leak, air pocket, or an external noise.
The inspections were completed in three separate deployments to ensure the greatest accuracy. To track the tool as it traverses the pipeline, receivers are placed strategically throughout the planned inspection route. As the tool traverses, it makes a sound that is recorded by the receivers to determine its position on the pipeline; this system allows leak locations to be estimated typically within 10-feet (3-meters) of the actual leak location.
BWWB’s survey located 26 leaks of varying size with close location accuracy. Twenty of the leaks have since been verified and repaired by BWWB, while the remaining six leaks have been deferred due to their size or matched up with existing features.
The SmartBall tool was able to detect several leaks that were as small as ~1 gallon (~3.8 liters) per minute to as large as ~15 gallons (~57 liters) per minute. This allowed BWWB to make informed repair decisions for each identified leak, allowing for the short-term deferral of some small leaks in favor of the larger leaks.
Through the location of both small and large leaks in its 2012 survey, BWWB was able to repair high priority leaks, but also identify the small leaks that can be repaired to prevent long term water loss. The project has provided BWWB with valuable information moving forward with the management of its large-diameter pipeline system.
Birmingham Water Works Board operates the largest water system in Alabama serving approximately 600,000 customers over 33 municipalities. It includes 3,900 miles (6275 km) of pipe and pumps 102 million gallons (386 million liters) per Day. Locating and repairing leaks on critical large-diameter pipelines remains an important initiative for BWWB in order to provide quality service to its customers.