Concordia researchers analyze alternative factors for water main breaks

Water main break researchers
The new paper published in the journal, Environmental Systems Research, includes data from 13 utilities in seven provinces. From left, Sadaf Gharaati with Rebecca Dziedzic. Photo Credit: Concordia University

While age, material and diameter are most often the culprits when it comes to water main breaks, a pair of Concordia University researchers has analyzed more than 62,000 breaks and found that the types of surrounding soil, or the type of pipe lining, coating or joint, are also notable factors.

The new paper published in the journal, Environmental Systems Research, includes data from 13 utilities in seven provinces, including inventories and histories of main breaks that covers almost 26,000 kilometres worth of pipes.

 “It is very rare to find a study that includes so many cities,” explained study co-author Rebecca Dziedzic, an assistant professor in the Department of Building, Civil and Environmental Engineering at Concordia in Montreal, Quebec. “Having access to this kind of data allows us to see different perspectives and ways of collecting data, as well as each utility’s different goals and results.”

Dziedzic co-authored the study with Sadaf Gharaati, MSc 22.

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A recent Utah State University study created from utility survey data estimates that some 20% of water pipes across the U.S. and Canada are in need of replacement and contribute to some 260,000 water main breaks each year. 

The utilities’ data for the Concordia study also has information on pipe diameter, material, length, installation year and failure year, among other variables, but the researchers were focused on lesser-known variables.

For instance, seasons play a role in determining the risks of a water main break, the study found. Summer breaks can often be accidental due to Canada’s short but intense construction season. However, more failures are experienced in January and February, during freezing winters.

“The utilities can use the data to implement better practices, such as improving communication with construction crews about the location and types of water mains in a particular area,” Dziedzic explains.

When it comes to soil conditions, pipes in clay and sandy soils are more likely to break than pipes in damper environments, the study found. Clay soil breaks are usually related to bedding issues, while those in sandy soil are linked to the way the structures settle.

Universal joints were more likely to fail than collared ones, the researchers noted, particularly for circumferential failures. Joints and fitting failures were most likely in pipes less than 20 years old, and usually the result of poor installation rather than pipe quality.

The majority of historical breaks recorded by the utilities occurred on older cast iron pipes. Because most of the PVC pipes were installed in the 1980s, or more recently, they have not yet reached the end of their expected service lives, the study found. 

“The hope is that we continue to work together with the utilities to create better predictions of future breaks,” Dziedzic concludes. “This way, they can maintain and manage their systems better within their budgets. Hopefully, we will be able to create better models that look at more factors and can help reduce the potential of restricting people’s access to clean water.”

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