Got Deteriorating Asbestos Cement Water Mains?
Proven CIPP technology can solve the problem
Asbestos has come to be one of the most feared words and materials in the world. Yet, in the 1940s, 50s and 60s, more than 600,000 miles of asbestos cement (AC) pipe, used for its light weight, corrosion resistance, rigidity, ease of handling and installation, was installed to handle water throughout Canada and the United States. Applications included potable water mains, storm drains and sanitary sewers.
Projected to have a 50- to 70-year life expectancy, decaying AC pipes today are a major source of asbestos in drinking water and pose even greater threats when they are removed or repaired. It is the 12 to 15 percent of chrysotile asbestos fibres added to the Portland cement for strength and corrosion resistance that causes the health hazards. So what are municipalities and public works entities to do?
Most provinces and states do not require public or private utilities or municipalities to remove and replace AC pipe. But the increasing incidence of decaying pipes in residential areas that should be considered for removal or rehabilitation by pipe bursting or pipe reaming are subject to strict and costly U.S. EPA or provincial bodies and regulations. Major downsides to this are both the high costs and naturally, safety concerns.
Health hazards associated with asbestos cement pipes, when asbestos fibres are inhaled, can be caused by breaking, cutting, drilling, filing, scraping, surface cleaning, sanding or even dismantling. Thus, the reasons for national agencies to step in when using the above ways to replace or repair this type of pipe.
But the good news is that solutions exist today – and that is CIPP (curedin- place-pipe lining). It has been found that this trenchless rehabilitation process presents a low-cost solution in situations where AC pipe can be rehabilitated. To date, several projects have demonstrated that CIPP is a viable alternative to other methods, and, as compared to the proven method of structurally relining cast iron piping, offers even greater savings.
Are there any options?
Alternative solutions to rehabilitate asbestos cement pipe to control dust and fibre-release require wet methods. These include water with surfactants, thickened substances, wet sponges, material softening agents, liquid adhesives or wet wiping, plus the proper handling of nearby water, piping and soil.
To accomplish this safely and cost effectively, current CIPP processes renovate water mains by lining the walls of existing mains with a hardened synthetic polymer tube and this is then cured using hot water. The method has been successfully applied to thousands of miles of cast iron and other metal water mains with a 99.99 percent degree of success. Recently there has been a growing number of projects and interest concerning rehabilitation of AC pipes. Such interest is especially prompted by the fact that it presents a solution to a huge problem, as well as a major cost saver.
The pros of CIPP With a growing number of projects in the works across Canada and the U.S., structural CIPP relining is being viewed as an optimum “interim” solution as the CIPP process can extend the life of the water main by 50 years or more. Obvious drawbacks of other removal or rehabilitation methods, other than huge potential costs, include meeting regulatory requirements.
Ongoing studies have shown that the possible health risks in AC drinking water pipes are technically difficult to measure. These studies have concluded, however, that there might be potential exposure to asbestos in the water through inhalation of aerosol fibres that might become trapped on clothes when washed and then emitted into the atmosphere.
Here is the bottom line why there is great potential for rehabilitating the 600,000 miles of AC water mains in the U.S. and Canada: the Aqua-Pipe CIPP process exposes to the environment far less asbestos than legislation requires. For instance, the EPA requires that no more than 260 linear feet of asbestos cement can be exposed or removed. In terms of CIPP, this means as much as 8,000 feet of AC pipe can be relined in any given location. Explained in other terms, since small pits and no trenches have to be dug at each end of the section to be repaired in a single rehabilitation project, as many as 40 pits or shafts can be dug without deep regulatory involvement or costs. While regulatory bodies have to be notified, the CIPP process can be accomplished without incurring huge costs while also conforming to strict constraints.
The major difference between working with AC pipe versus cast iron pipes is in the way it is cut. By scoring AC pipes, thus causing minimal, if any, asbestos emissions, rather than cutting them, the small amount of water, material and soil in the area possibly contaminated by asbestos may be carefully removed, filtered and disposed of according to regulatory guidelines. Personnel from one or more trenchless technology firms are currently engaged with laboratories conducting airborne fibre testing to determine what, if any, additional steps or procedures need to be taken to ensure the safety of asbestos cement water main pipe rehabilitation and repair.
Reasons to procrastinate may be over
Thus, it is no longer necessary for municipalities or utilities to avoid or prolong rehabilitating AC pipes but rather they can embrace current technology that is successfully being applied to cast iron pipes, to restore residual breaks and leaks and to renew structural capacity.
As noted previously, costs as compared to other methods are far less; trenchless technologies offer faster and less disruptive solutions (the time factor from start to finish may be as little as five weeks); post-lining reinstatements of service connections are all done from within the pipe; and the linings not only give an additional 50+ years of life to the water mains, but are also certified by NSF to NSF/ANSI Standard 61.
Regulatory bodies strongly encourage customers of municipal and private water companies to learn more about their drinking water. But prior to inevitable growing ranks of citizen complaints or further regulatory constraints or strictures, it would be advisable for those responsible for drinking water installations and repair to not only take steps to repair or rehabilitate deteriorating AC piping, but look into proven technologies now being successfully and cost-effectively applied to cast iron pipes.
To summarize, miles and miles of asbestos cement pipe either has or will reach the end of their useful lives. Most repair or replacement techniques are not truly an option and those responsible should not only be aware of the situation but also act to resolve it.