Fresh, running water is a concern that plagued civilization for centuries. As early as 1692, the City of Boston used bore logs to aid in firefighting efforts. At the beginning of the 1800s, using wood as the construction material for main water lines became obsolete. Cities turned to iron to transport fresh water to the denizens. Iron mains allowed municipalities to run water at a higher pressure. In addition to using cast iron plumbing, eventually, some areas used iron permeated with asbestos fibers to transport water to their residential properties; this material would later be known as asbestos cement. (Learn more in "Asbestos Cement Pipe, Why It's a Problem and How Trenchless Can Fix It.")
While these cast iron and permeated pipes work well in most situations, there are growing concerns about how well maintained these lines are. Age and ground conditions affect the plumbing running underground. However, there is a way to repair any damage without lengthy repair time using trenchless construction.
Water Main Lines Are Deteriorating
While cast iron pipes do have a life span of approximately 120 years, newer metal tubes have thinner walls and are only rated to last 100 years. Even the relatively recent invention of polyvinyl chloride (PVC) has a life expectancy of only 75 years. As we move into the 21st century, these pipes are beginning to deteriorate. Previous statistics for water main repair showed an annual replacement rate of just 0.3 percent. However, as the cast iron plumbing starts to wear out, repair and replacement rates rise to around two percent.
While two percent does not sound like a lot, repairs come at a significant cost. In the United States, to repair or replace two percent of the water distribution network costs local and federal governments between $4.2 and $6.3 billion annually; other reports put the total cost close to $1 trillion. Additionally, water main breaks cause issues not just for the residential consumer, but for services such as fire departments who need access to these services to protect the public.
There are several solutions to this massive problem. One solution is Cured-in-place pipe (CIPP) as a repair and replacement technique. (Learn more in "Why CIPP is Growing Rapidly for Drinking Water Mains.")
What is CIPP?
Cured-in-place pipe, better known as CIPP, is essentially a pipe within a pipe. The new plumbing is a textile liner permeated with liquid resin. Before the lining hardens, it is flexible, allowing technicians to insert it into the existing pipe. Once in place, it cures or hardens to form a new, seamless pipe.
The benefit to using CIPP is two-fold. First, CIPP is a trenchless plumbing solution. Instead of digging up the entire pipe and replacing it with a new one, workers only dig small trenches to access points in the plumbing network. The lining is inserted here and run through the existing line.
An additional benefit comes from dealing with the complexity of the existing water pathway. There may be many twists and turns to the existing plumbing that makes replacing each section difficult. Before curing, CIPP is flexible enough to accommodate many bends.
How Does CIPP Compare to Other Methods?
Traditionally, repair of damaged or deteriorating pipes requires much digging. In the past, workers expose the entire line, cut the damaged area out, and replace it with new plumbing. The costs for this method was around $250 per foot of pipe, making it the more expensive and lengthier option. Structures built on easements can make traditional methods difficult to perform.
When compared to traditional trenching methods, trenchless options are more cost efficient and take less time. CIPP, while one of the most modern methods, is not the sole trenchless method used to repair and replace deteriorating water lines. Some municipalities turn to pipe bursting techniques to replace badly damaged lines. With this approach, technicians dig two trenches at either end of the work area. The new line with a bursting tool attached is running through the line, breaking apart the old line and allowing the new one to take its place. This method does have many benefits and may be ideal for pipes too damaged for CIPP to work efficiently, however, it does cost between $60 and $200 per foot. But, it is still less than conventional trenching takes less time, leaving behind less soil disruption as well. (Read on in "An Introduction to Pipe Bursting.")
Of all of the available options, CIPP is the most cost effective, averaging $160 per foot. Unlike pipe-bursting, technicians only dig one small hole to access the pipe. Then, they run the lining through the existing pipe and allow it to cure. Pipe lining is less invasive than all other methods.
Where Has CIPP Been Used?
Cured-in-place pipe originated in London in 1971. While the new technique took off in Europe and Japan in the 1970s, it was not until the 1980’s that the United States got on board with the process. Since then, several major cities have incorporated CIPP as one of their pipe repair and replacement techniques.
The city of Atlanta, Georgia uses CIPP in their water main repairs as one of their trenchless maintenance options. To date, the city has restored over 8,000 feet of their water lines with CIPP.
In the city of Wausau, Wisconsin, workers had to contend with a particular section of line breaking. Between 1980 and 2015, the municipality had repaired the over 1,000-foot section of line running underneath Sunset Drive eight different times. The iron pipe continually broke due to surrounding conditions. To avoid constant replacements, workers employed CIPP techniques to repair the problem.
While Wausau had a breaking problem, Appleton, Wisconsin had the issue of a slow leak. Conditions at the site made other trenchless methods, such as pipe-bursting, unfeasible. The city decided to use CIPP on the 280-foot pipe to fix the leaking problem they experienced.
Cured-in-place pipe is a solution that corrects many water main problems. Across the country and around the globe, municipalities use CIPP as their top choice to successfully correct deterioration issues. By choosing CIPP, these governments save the cities using this technique both time and money in their rehabilitation projects.