Asbestos Cement Pipe: Why It's a Problem and How Trenchless Can Fix It
Traditional trenching and replacing asbestos-infused pipes is costly and hazardous. Trenchless pipe bursting allows replacement of the pipes without exposing asbestos to the air.
Asbestos is a dangerous fiber that has been in use for decades. As a natural substance, ancient civilizations used asbestos because of its ability to burn without damage; Egyptians used asbestos to wrap the bodies of the dead to protect them from deterioration, and the Greeks also used cloths made from this mineral to wrap their dead before putting them into the funeral pyre to keep the body’s ashes from being mixed with that of the fire itself.
In addition to protecting the bodies of the recently deceased, asbestos continued to grow in popularity throughout the centuries. The Romans and Greeks used the mineral fibers in tablecloths, napkins and clothes. As modernization emerged and industrialization took place, fibers found their way into everyday items such as roof coverings, pottery and pipes.
Problems with Asbestos in Pipes
Asbestos was first used in plumbing in 1931 when the fibers were mixed with concrete to make the tube more structurally sound; this material was called asbestos cement. By the early 1950’s, these concrete tubes were commonly used by cities as they were designed to last for around 70 years. Since then, around 400,00 miles of asbestos pipe resides in the United States.
There are problems with using asbestos in everyday construction. Since the late 1800s, scientist found links to the utilization of this fibrous mineral to pulmonary diseases including mesothelioma, a deadly form of lung cancer. Workers who were exposed to working with this material decades ago began to experience cancers and other health issues. While this material is no longer acceptably used in the US for construction, it still poses health hazards to today's society. Air exposure is especially hazardous for workers who are attempting to replace asbestos pipes, as the fibers become airborne during the extraction process. Workers then inhale the fibers causing respiratory issues.
Asbestos affects today's communities through their plumbing infrastructure. Despite their longevity, these pipes are beginning to break down. This crumbling of concrete is allowing the fibers to enter the water flow. Asbestos fibers become attached to clothing washed in water from these lines, enabling them to become airborne. Also, fibers loosened from the concrete clog pipes.
Solution Options to Fix Asbestos-Laced Pipes
Digging up and replacing asbestos-infused pipes is just one solution to the problem. This solution, while optimal, does pose risks of its own. Not only is it costly, but the traditional process of digging up the plumbing lines sets the fibers free in the air. Workers could potentially inhale these fibers causing pulmonary irritation and possible respiratory diseases.
There is an alternative to exposing the pipes. Pipe bursting allows replacement of the pipes with new lines without exposing the asbestos fibers to the air. Studies show that city workers replacing asbestos-infused plumbing with this method’s exposure levels were well below the permissible exposure level of 0.1 fiber structures per cubic centimeter of air.
Another very feasible option is the installation of a cured-in-place lining. This lining, which does have fibers infused within, does not use asbestos. Insertion into the existing pipe occurs without having to expose the plumbing and workers do not have to worry about accidentally inhaling fibers. Once inside, the lining hardens and offers a smooth, clean interior for water to travel through. Asbestos from the existing pipe cannot penetrate the lining.
Similar to the cure-in-place (CIPP) option is the spray-in-place (SIPP). Like CIPP, SIPP installs a coating on the interior of the existing pipe. This process uses polymeric materials pumped through a hose with a rotating spray head. The tube allows the polymeric material to coat the pipe in a thick layer. Once in place, the line is inspected, disinfected, and flushed before being put back into use. While CIPP is common in the United States, SIPP is also gaining popularity.
Some municipalities, however, opt to leave the asbestos lines where they are. Instead, they run new water mains parallel to the existing ones. This method of abandon-in-place is an option so long as the city fills the no longer in-service lines in with grout per EPA suggested guidelines.
How Trenchless Technology Plays a Role
The most common solutions to resolve asbestos in water lines utilize trenchless technology. Pipe bursting only requires two small wells dug at the beginning and end of the line. One hole allows insertion of the breaking tool and new line. The other allows for retrieval of the device and any old pipe pieces it pushes out. Of course, this helps to limit the number of asbestos fibers released into the air.
When using cured-in-place pipe (CIPP), insertion of the liner into the pipe occurs at the connection point. No other areas must be exposed. The liner is rolled into the existing pipe and allowed to harden over several hours.
In a similar method, spray-in-place (SIPP) coatings are sprayed on by a hose inserted into the plumbing. The hose may be on the back of a robot that allows the workers to navigate the pipe going up to several thousand feet. Like CIPP, only the connector area is unearthed so that the hose is inserted.
The use of trenchless technology allows the replacement or resurfacing of the pipes to be completed quicker than traditional digging methods. Trenchless solutions also help to limit the exposure of workers to harmful asbestos fibers.
Asbestos is a strong, resilient mineral naturally occurring in the ground, which is potentially hazardous if inhaled. Replacing or resurfacing water mains infused with asbestos fibers helps to limit the amount of exposure. Through the use of trenchless solutions such as pipe bursting and CIPP, workers can eliminate contamination for water lines while limiting their exposure to the harmful materials as well.