Article

Calgary Proactive Condition Assessment Bar Wrapped Pipe Bwp

Inspection methods for BWP and steel pipe that locate cylinder corrosion have only recently been developed and commercialized. Specifically for BWP inspection, tools that can identify both bar breaks – which are an indication of corrosion – and corrosion on the steel cylinder are the best for completing a thorough condition assessment.

The City of Calgary provides water and wastewater services for over 1 million people in the Greater Calgary area; many of its large-diameter transmission and sewer force mains are made of PCCP and BWP.

In an annual proactive condition assessment program, the City of Calgary inspects its PCCP and BWP for signs of deterioration using electromagnetic (EM) technology.

In May 2013, the City inspected 1.6 miles (2.2 km) of the 30-inch (750-mm) BWP Memorial Feedermain using PureRobotics™, which is a powerful robotic system equipped with PureEM™ technology that can be configured to inspect a variety of pipelines and materials with different operational conditions. In BWP, it is capable of locating both bar breaks and cylinder corrosion.

In August 2013, the City verified the results with Pure Technologies by excavating a pipe section that was identified as distressed during data analysis.

The results from the inspection identified only 3 of 232 BWP pipe sections with evidence of bar breaks, as well as 3 additional pipe sections with evidence of cylinder anomalies.

Pure Technologies’ data from over 8,000 miles of pressure pipe condition assessment indicates that only a small percentage of pipes (less than 5 percent) are in need of repair and therefore have a significant remaining useful life. Condition assessment data also suggests that pipe distress is localized and a significant ROI can be achieved by locating and addressing isolated problems through structural inspection.

In August 2013, the most distressed pipe section was excavated for verification. The results had predicted bar breaks and cylinder corrosion, which can eventually lead to pipe failure if not repaired or replaced. The validation confirmed the broken bars and a large area of cylinder corrosion.

Staff verify the pipe condition

Pure Technologies staff verify the pipe condition

Pipe verification

Verification of one pipe revealed bar breaks and corrosion.

The City of Calgary was pleased with the results, and through condition assessment, has been able to identify and address individual distressed pipe sections on an otherwise serviceable transmission main. This has allowed the City to avoid a potential rupture of the main in a high consequence area while increasing service reliability and the useful life of the Memorial Feedermain.

The other sections identified in the inspection have been prioritized and will be verified in a future repair cycle.

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Case Study

Case Study: City of Calgary Memorial Feedermain

In August 2013, the City of Calgary and Pure Technologies verified bar breaks and cylinder corrosion on a 30-inch Bar-Wrapped Pipe section on the Memorial Feedermain. The distressed pipe was identified in an annual inspection completed in May 2013.

Pipeline Inspection and Condition Assessment Services

Pipeline Inspection and Condition Assessment Services

We provide water and wastewater organizations a comprehensive suite of technologies that provide actionable pipeline information to better understand the condition of their pipe.

Technical Paper

Failure Risk of Bar-Wrapped Pipe with Broken Bars and Corroded Cylinder

This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.