repaired joint leak

How Proactive Pipeline Management Improves Outcomes for Two Alberta Communities

Over the last five years, The Economist has consistently ranked Calgary among the world’s top 10 most livable cities. The City of Calgary’s water infrastructure plays a vital role in livability both in the city and across the region, as Calgary supplies drinking water to several neighboring communities including the City of Airdrie.

Airdrie, located directly north of Calgary, is one of the fastest growing cities in Canada. At the same time, drought and aging infrastructure are increasing concerns for the region. To secure its water supplies and maintain vibrant, livable communities, the cities of Calgary and Airdrie are leveraging data to proactively manage their buried infrastructure.

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In 2023, the two cities partnered to inspect the jointly owned Airdrie Feeder Main. This critical pipeline supplies the majority of clean water to Airdrie’s approximately 80,650 residents. The team used Xylem’s SmartBall platform to screen the pipeline’s health and search for leaks.

Leak Detection as Condition Assessment

In 2004, the City of Calgary committed to continuous improvement of its condition assessment program for concrete feeder mains. Concrete pipelines, like the Airdrie Feeder Main, make up 64 per cent of the city’s feeder main network by length. The city has performed extensive risk analysis to prioritize these pipelines for inspection.

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The Airdrie Feeder Main is a 900-mm pipeline constructed in 1981 from prestressed concrete cylinder pipe (PCCP). The pipeline moves water about 13 km from a metering chamber in Calgary to the Airdrie Pumping Station. This pipeline is considered highly critical because it services most of Airdrie, has limited redundancy, and has a high consequence of failure.

The Airdrie Feeder Main has an impressive condition assessment record dating back to 2007, including three prior leak detection inspections. A pipe wall assessment completed between 2017 and 2019 showed the pipeline was in good condition with distress rates well below the average of 3 to 4 per cent for PCCP pipelines.

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Leak detection is an important part of the City of Calgary’s condition assessment program. The city has dedicated field staff for conducting external leak detection surveys using acoustic microphones, geophones, and correlators. These tools are effective for identifying leaks in the distribution system. However, they are less effective for large-diameter pipelines. Inline leak detection fills this gap in the feeder main network and provides an added layer of condition data.

Inline leak detection is an economic way to screen pipelines for problem areas and look after their condition on a more routine basis. Inline leak detection is also an effective complement to electromagnetic pipe wall inspection because it can identify issues related to joint movement, cylinder defects, and sheer failures. There is a blind spot at the pipe joints when using electromagnetic inspection technology. However, issues at the joints often result in leaks, so tools like SmartBall provide an effective indication of joint health.

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joint leak on the Airdrie feeder main

Partnering for Success

The cities of Calgary and Airdrie were planning a leak inspection in 2023 as a follow up to the 2019 pipe wall assessment. During planning, they discovered abnormally high chloroform levels in a valve chamber on the Airdrie Feeder Main. This elevated the need to find the source of chlorinated water.
The cities of Calgary and Airdrie worked collaboratively with Xylem to plan the inspection. Site visits and extensive coordination helped ensure there were no surprises on the day of the inspection in August 2023.

A free-swimming inspection tool, SmartBall was able to cover the long distance between Calgary and Airdrie in a single deployment and meet the cities’ need to keep the pipeline in service during the inspection. SmartBall is also actively tracked during inspections, enabling the City of Airdrie to minimize disruption by performing just-in-time closures of their service connections.

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The team inserted the tool under pressure through a 150-mm drain gate valve at the City of Calgary’s metering chamber. SmartBall traveled through the pipeline recording acoustic data for just over seven hours. Once the tool arrived at the Airdrie Pumping Station, the City of Airdrie isolated the main and retrieved the tool using a strainer basket.

Inspection Results

Reviewing acoustic data from the inspection, Xylem analysts identified one leak at a pipe joint. They determined the leak location based on known features and information from the tool’s internal accelerometer and gyroscope. The leak wasn’t surfacing, but a dig sheet and onsite support helped guide the team to the leak location.

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The City of Calgary excavated the pipe and determined the leak was caused by a rolled rubber gasket at the joint. A welded repair addressed the issue, and the city refilled and returned the line to service within a week.

Corrosion and eventual breakage of steel prestressing wires is one of the leading causes of PCCP failure in Calgary. However, it is not uncommon to see failure caused by other factors. The joint leak was not located on or adjacent to pipes identified with wire breaks in the 2019 pipe wall assessment. This emphasizes the importance of combining leak detection and pipe wall assessment to capture a wide range of failure modes.

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PureTech Smart Ball

Regional Outcomes

As droughts become more frequent and severe, water loss is under growing scrutiny in Alberta. It’s important for cities like Calgary and Airdrie — which rely on the Bow and Elbow Rivers for their water supply — to find and address as many leaks as possible. This will help ensure long-term sustainability for the area’s water users.

Proactive inspection and repair are a powerful way to maintain reliability of the water supply network and costs a fraction of the price of an emergency repair following a failure. Repairing this leak reduced water loss, protects the regionally important Airdrie Feeder Main, and provides additional data for managing this asset into the future.

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The Airdrie Feeder Main is a critical pipeline in a transmission network spanning more than 460 km across Calgary and the region. The City of Calgary launched a proactive feeder main condition assessment program in 2004 and has since inspected just over 25 per cent of their transmission network.

Justin Hebner is regional sales manager at Xylem; Kyle Hentschel, is an infrastructure engineer at City of Calgary; Rita Zhang, is a water utilities planning engineer at City of Calgary; and Terry Parks, is facilities coordinator at City of Airdrie.

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