No silver bullet technology for pipeline condition assessment
For utilities with large-diameter networks, waiting for failures to occur before repairing or replacing highly critical mains is not an option.
With a large amount of buried water infrastructure reaching the end of its service life, operators have every incentive to take a proactive approach to asset management.
Nowhere is this more critical than in busy urban centres. The fallout from an unexpected failure can have major societal costs, and greatly diminish public confidence in the utility.
Asset management begins with condition assessment
Successful asset management begins with condition assessment, the point at which problems and challenges are understood and shaped into definitive plans from both an operational and financial perspective.
To proactively address their pipeline conditions, operators today have access to variety of tools, technologies and engineering analysis that allow for a comprehensive condition assessment of large-diameter pressure pipes, for both water and wastewater systems.
“Unfortunately there is no ‘silver bullet’ with regard to condition assessment technologies,” said Mike Wrigglesworth, Senior Vice President of Pure Technologies. “Each pipeline is unique, and no single technology is the fix for all situations. A combination of factors, from pipe material to soil conditions, operational challenges, age, installation and third party factors will all play a role in the likelihood of failure. Combined with the consequence of failure, a risk-based approach can then be used to select the best condition assessment tool or technologies.”
Matching assessment technology with the pipeline conditions and project goals
While operators can now deploy a number of data-based tools and techniques to assess pipeline conditions, each technology also comes with varying degrees of limitation. For instance, while magnetic flux leakage (MFL) tools provide the highest resolution data for steel pipe, MFL is of limited value for concrete pipe.
Medium resolution techniques such as electromagnetics can identify localized areas of wall loss on metallic pipes such as ductile iron and steel, but not on cast iron pipe as cylinder thickness is often too thick and material properties vary considerably, negatively affecting results. In both cases, it is often prudent to deploy leak detection technologies, as studies show joint defects lead to leaks, and leaks are precursors to failure.
“Often the best solution is to use different but complementary technologies to collect robust condition data that is then evaluated using engineering analysis against a comprehensive risk of failure versus a consequence of failure analysis.”
Sahara® Leak and Gas Pocket Detection
Pure’s proprietary Sahara® inspection platform is a tethered, multi-sensor tool that can identify acoustic-based leaks, gas pockets and visual anomalies in real time, with no disruption to service.
The Sahara tool features a small parachute that uses the product flow to draw the sensor through the pipeline while being controlled from the surface.
SmartBall® Leak and Gas Pocket Detection
SmartBall® is a multi-sensor tool used to identify a variety of conditions in pressurized pipelines. The tool is easy to deploy through existing pipeline features, and travels untethered with the product flow, collecting information.
The tool’s highly sensitive acoustic sensor can locate small leaks and gas pockets, with typical location accuracy within 6 feet (1.8 m).
PipeDiver® Condition Assessment
PipeDiver® is a free-swimming condition assessment tool that operates while the pipeline remains in service.
Originally designed for use in PCCP, the tool has electromagnetic sensors to identify and locate broken prestressing wire wraps. For metallic pipelines, the optimized PipeDiver has the ability to pinpoint localized areas of wall loss.
The tool is also able to deliver video images from inside the pipe.
PipeWalker™ Condition Assessment
The PipeWalker tool provides a viable option for pipeline condition assessment in situations where the pipe is dewatered or where the option to dewater is available.
The tool is equipped with electromagnetic sensors for detecting wire wrap breaks on PCCP pipes and for detecting corrosion on metallic pipes.
PureRobotics® Pipeline Inspection
PureRobotics® is a depth-rated robotic pipeline inspection system that can be configured to inspect pipe applications 24-inches and larger.
Tethered by a high-strength fiber optic cable, the crawler is capable of performing multi-sensor inspections in dewatered pipes or while submerged in depressurized pipes.
The crawler features HD digital CCTV, and can be equipped with electromagnetic sensors, Inertial Mapping, 3-D LIDAR, LASER, SONAR and other tools upon request.
Matching the level of resolution to the risk of the line
While there are a variety of approaches available for assessing a pipeline’s condition, much of an operator’s effort must go into matching the level of resolution of the approach to the overall risk of the line.
The idea is to put the highest resolution technologies on the most critical lines. In the end, the goal of deploying a particular technology (or complementary technologies) is to identify and locate the areas that need rehabilitation or repair as opposed to wholesale replacement of those lines.
Armed with the right information, operators can determine remaining useful life, and confidently move forward to prioritize and target capital spending, while avoiding failures.