Canada’s asbestos cement water pipe research — a brief history

Deteriorated asbestos cement pipes can shed fibres into the water and pose a hazard of cancer. A national / provincial / municipal research facility was established in Regina in 2003. The Centre for Sustainable Infrastructure Research (CSIR) was located there because Regina had the unenviable distinction of having a preponderance of asbestos cement water supply pipes, offering the opportunity of being a “real life lab.”

Scientists produced many studies of asbestos cement (AC) water pipes, and refer to asbestos fibres in water as a “health concern.” The Centre for Sustainable Infrastructure Research has since vanished, but its archived studies and other documents pay testament to its existence.

Bibliography of NRC/CSIR Studies, 2003 – 2012

The following are the studies and extracts from the Regina Centre that we have identified to date.

Failure conditions of asbestos cement water mains in Regina. Hu, Y, Hubble, D.W. (2005)

Canadian Society of Civil Engineering (CSCE) 33rd Annual Conference [Proceedings], pp. 1-10, 2005-06-01
https://nrc-publications.canada.ca/eng/view/accepted/?id=c34d0b6b-fd9c-4592-b14a-b5661387492e

Approximately two thirds of the water mains in the City of Regina are asbestos cement (AC) pipes. These pipes are experiencing more and more failures in recent years and account for almost all of the water main breaks in the city. Climate and soil conditions are the two critical factors, along with pipe age, diameter, and construction and repair methods that all influence the condition and breakage of the AC water mains in Regina.

Factors contributing to the failure of asbestos cement water mains. Hu, Y, Hubble, D.W. (2007)

Canadian Journal of Civil Engineering, 34, May 5, pp. 608-621, 2007-05-01
https://doi.org/10.1139/L06-162
https://nrc-publications.canada.ca/eng/view/accepted/?id=a9b16786-8e97-4eef-b022-a9957672c4f6

Pipe age, diameter, climate, clay soil, and construction and maintenance methods all influence the failure of AC water mains in the city of Regina, with climate and clay soil conditions being the two critical factors. Some chemical attack from the conveyed water and soil pore water may have occurred and detrimentally affected the structural integrity of the AC water mains.

Instrumentation of asbestos cement pipe in expansive soil. Hu, Y Vi, HQ, Loftian, K. (2008)

American Society of Civil Engineering International Pipelines Conference. Atlanta, GA., U.S.A. pp. 1-10
https://nrc-publications.canada.ca/eng/view/object/?id=1a490706-a461-40b7-89da-bf28e8f60749

The City of Regina, SK, Canada, was developed on a post-glacial lake deposit that is highly plastic, unsaturated, expansive clay. The water distribution system has about 530 km of asbestos cement (AC) water mains, and the rate of water main breakage has increased recently in old areas. A study was conducted by the National Research Council Canada, Center for Sustainable Infrastructure Research in Regina to investigate the causes of failures of the water mains.

Field instrumentation was successfully installed to monitor the performance of a replacement section of an AC water main in south Regina, where failures are frequent, to learn about soil behaviour and its interaction with this type of pipe. The instrumentation included sensors to measure pipe wall strains, in situ soil water content, soil movement, soil stress and temperature. Measurements were made in the pipe trench backfill and in the native soil around the backfill. This paper presents the first year monitoring data of the test section.

Asbestos cement water mains: history, current state, and future planning. Hu, Y; Wang, D.L.; Cossitt, K (2008)

60th Annual Western Canada Water and Wastewater Association Conference [Proceedings], pp. 1-13, 2008-09-23
https://nrc-publications.canada.ca/eng/view/object/?id=3b76bd1e-8f6c-49cc-a77d-8298f2481d6d

A review of available AC pipe information, including manufacturing methods, chemical composition, and the environmental factors that affect their deterioration and failure. The use of AC pipe was largely discontinued in North America in the late 1970s due to health concerns associated with the manufacturing process of AC pipes and the possible release of asbestos fibres from deteriorated pipes. However, AC pipe is still a significant portion of the water distribution system of many cities. Current efforts and methods for assessing present pipe condition and forecasting future pipe performance will form the basis for developing management strategies to plan and implement optimal rehabilitation and replacement programs for AC pipes in drinking water distribution systems.

AC pipe in North America: rehabilitation/replacement methods and current practices. Hu, Y; Wang, D.L; Baker, S; Cossitt, K (2009)

https://nrc-publications.canada.ca/eng/view/accepted/?id=fa9decd0-8bb2-486d-b6b9-46b75753fe37

Trenching is the main method to repair, rehabilitate, and replace AC pipes. Of many factors utilities chose to address AC pipes was coordination with other capital projects, followed by pipe breakage rate and pipe age. Cost was the main reason utilities chose a particular method; they generally did not consider environmental effects of possible release of asbestos fibres as their highest priority when selecting methods to renew AC pipes.

Safety and waste management of asbestos cement pipes. Wang, D.L.; Hu, Y; Chowdury, R. (2010)

https://nrc-publications.canada.ca/eng/view/accepted/?id=de94066d-dc98-4a4e-baaa-8de831da21d2

Utilities in Canada and the U.S. were surveyed regarding replacement of AC pipes and waste disposal – either abandonment in situ or waste disposal.

Although there are fewer health concerns about waterborne asbestos fibres, there are still concerns about the inhalation of airborne asbestos fibres from showers, humidifiers, etc. There are also some concerns about the ingestion of fibres from drinking water as well as the clogging of filter systems.

Recommendations are summarized for AC pipes projects and waste disposal.

Bacteriological challenges to asbestos cement water distribution pipelines. Wang, D.L.; Cullimore, D.R. (2010)

Journal of Environmental Sciences, 22, (8), pp. 1203-1208, August 01, 2010
https://nrc-publications.canada.ca/eng/view/accepted/?id=490173b5-8ba7-4559-8a1e-7e08403e1c9d

In recent years, increased water main breaks have occurred in the AC portions of some pipe networks. This can be partially attributed to the corrosion of the aged pipes by acid producing bacteria, slime forming bacteria and heterotrophic aerobic bacteria.

Severely deteriorated AC pipes also release asbestos fiber into the drinking water and could pose a hazard of malignant tumours of the gastrointestinal tract and other organs in consumers (WHO, 1991; Andersen, et al., 1993; Cherubini, et al., 1998; Browne, et al., 2005).

AC pipe in North America: inventory, breakage and working environments. Hu, Y; Wang, D. L.; Cossitt, K; Chowdury, R. (2010)

https://doi.org/10.1061/(ASCE)PS.1949-1204.0000064
https://nrc-publications.canada.ca/eng/view/accepted/?id=fa9decd0-8bb2-486d-b6b9-46b75753fe37

Utility managers’ perceptions of water and soil environments were not always consistent with water and soil test results. Pipe age, water quality, and pipe size are important factors contributing to the failure of AC pipes in North America.

Biodeterioration of asbestos cement (AC) pipe in drinking water distribution systems. Wang, D.L.; Cullimore, R.; Hu, Y.; Chowdhury, R. (2011)

International Biodeterioration & Biodegradation. 65(6), 810-817, 2011
https://nrc-publications.canada.ca/eng/view/object/?id=084f0596-f366-44d0-b75f-028fc56a71a0

The recalcitrant asbestos fibers within the deteriorated cement matrix become an interwork of asbestos fibers and quartz particles. At this stage, the AC pipe loses its structural strength and becomes fragile. A minor disturbance, such as pressure changes from water hammer, can result in a release of biofilms and asbestos fibers into the drinking water, causing a health concern.

Condition evaluation of asbestos cement water mains. Chowdury, Rudaba; Hu, Yafei; Wang, Dunling. (2012)

Pipelines 2012, pp. 288-297, 2012-08-22
https://nrc-publications.canada.ca/eng/view/object/?id=c1f24ea1-3593-4796-93e2-3745fa48dfbf
https://ascelibrary.org/doi/10.1061/9780784412480.026

Visual inspection, hardness and crush tests, and phenolphthalein [acidity/alkalinity] tests were carried out on pipe samples collected from three utilities to assess the current condition of their AC pipes. AC pipes were vulnerable where soils have high water tables with high sulphate contents, and when the carried water is aggressive [e.g., soft water]. 
Note: 2011 research above attributed “aggressiveness” to anaerobic bacteria.