The American Society of Civil Engineers states in their 2021 Report Card for America’s Infrastructure that there are over 800,000 miles of public sewer lines and 500,000 miles of private lateral sewers. The report further notes that utilities spent over $3 billion in 2019 to replace just 4,700 miles of pipeline. While many utilities are replacing sewer pipes, more and more are using sewer pipe epoxy lining rather than repiping them. This article defines epoxy lining and examines the pros and cons of repiping versus epoxy-lining sewer pipes. It also documents the process used to obtain the best sewer pipe epoxy lining results.
What Is Sewer Pipe Epoxy Lining?
There are two types of sewer pipe epoxy lining: cured-in-place linings and spray-in-place lining. With a cured-in-place lining, a flexible tube is inserted through an existing pipe. That tubing is then bonded to the inside pipe surface. With a spray-in-place lining, an epoxy coating is sprayed inside the pipe using high-tech machinery. It bonds in a few hours, sealing the existing pipe from leaks.
With cured-in-place linings, the bonding process involves inflating and heating the sleeve to cure the liner’s polyester or vinyl resin. Unfortunately, that lengthy heating and curing process can cause health-threatening noxious fumes that spread throughout the sewer lines, exposing people to hazardous air pollutants such as styrene, methylene chloride, and dibutyl phthalate.
With spray-in-place linings, the resin heating happens only when the epoxy is sprayed onto the pipe surface. That also allows curing within 2 to 3 hours rather than the two- to three-day requirement for cured-in-place epoxy coatings for sewer lines.
What Are the Pros and Cons of Epoxy Coating for Sewer Lining Plumbing?
Spray-in-place epoxy pipe lining offers several advantages over digging and repiping sewer lines.
- Minimal Digging. There’s no need to dig up the entire pipe. Often only a 6×6 foot access pit is needed every 650 feet. In some cases, access through existing manholes is the only requirement. It requires only 5% of the trenching and excavating time needed for repiping.
- Limited Disruption. Spray-in-place epoxy pipe lining plumbing takes roughly 15% of the time required to dig up and replace pipes. It avoids shutting down facilities as the repairs are underway, which can take a considerable time for an entire repiping project.
- Safe and Durable. Epoxy spray systems provide a protective barrier between the pipe and wastewater. This prevents any leaks from the pipes and environmental hazards. The life expectancy is roughly 75 years.
- Cost-Effective. Repiping is 50% to 75% more expensive than spray-in-place epoxy coating for sewer lines. The cost of digging, removing, replacing, and shutting down the digging locations is substantially reduced.
There are a few potential downsides or differences with sewer line epoxy linings compared to repiping.
- New Pipes. Of course, with repiping, after considerable digging, expense, and disruption, you do end up with all new pipes.
- Pipe Capacity. An epoxy lining does reduce the pipe capacity by the thickness of the lining. This is usually relatively minimal, but it is a factor.
- Tuberculation and Corrosion. Tuberculation can be removed from the pipe’s interior, but it is still there. It can re-emerge, but not typically before the expected lifetime of 50 to 75 years for epoxy-coated sewer lines. Likewise, internal epoxy coating for sewer lines will not address exterior corrosion.
- Pipe Surface Preparation and Application. If the pipe surface is not prepared correctly, it can lead to insufficient epoxy bonding. Our visual inspection process by robotic closed-circuit television identifies this problem before the epoxy lining is applied. Similarly, uneven distribution of epoxy can happen when a blown-in application process is used. Therefore, it’s best to use a spray-in-place system followed by a robotic video inspection.
The challenges from pipe surface preparation and application are primarily based on the experience and expertise of the epoxy pipe lining companies. The best companies use the best technology coupled with world-class processes.
What Is the Spray In Place Solutions (SIPS) Process?
There are lots of epoxy pipe lining companies. The key to selecting the right one is to examine closely the process they use. It must follow detailed procedures to ensure the lining corrects the problem and lasts for the estimated 75-year lifespan. Here’s the process we use.
- Pipe Mapping. We map the pipe to verify project details. A robotic closed-circuit television camera examines the entire length of the pipe and identifies all issues.
- Drag Scraping. A drag scraper, pulled in both directions, removes rust and debris. That also helps return the pipe to its original diameter.
- High-Pressure Water Jetting. Water jetting is then used to remove any remaining scaling, dirt, and film.
- Surface Prep Verification. At this point, our robotic closed-circuit camera is used to verify that the pipe has been cleaned sufficiently for the epoxy application.
- Spin Casting Epoxy Application. A state-of-the-art robotic spin cast system applies the epoxy to the pipe. During the application, the epoxy mix ratio, temperature, and speed of the spray head are continuously monitored to ensure the correct thickness is obtained.
- Curing and Final Inspection. The pipe is fully submersible after a brief two to three-hour cure time. Then we conduct a full inspection using the robotic closed-circuit television to verify full coverage.
Note that this process is used for all our epoxy spray-in-place solutions, whether that is sewer pipes as described here or for water mains as described in our article How Trenchless Pipe Lining Can Fix Potable Water Systems and in our recent project for the City of Houston’s 24-inch cast iron potable water main.
Why Choose Spray In Place Solutions (SIPS) for Epoxy Lining for Sewer Pipes?
Plenty of epoxy pipe lining companies exist, but Spray In Place Solutions (SIPS) offers a state-of-the-art, technologically advanced method that far outperforms the competition. So don’t just take our word for it. You can explore our many projects, including our 8” sewer pipe restoration project in North Carolina that restored 2,653 feet of a sewer line.
Spray In Place Solutions (SIPS) is certified compliant with ASTM 729. Therefore, you will not need to worry about wildlife being harmed by our materials or processes. We are also certified compliant with NSF/ANSI 61. This means rigorous testing has been done to ensure our epoxy coating is safe for drinking water.
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Ready to Get Started with Trenchless Pipe Lining to Fix Your Sewer Pipe Problems?
Are you ready to discuss how Spray In Place Solutions’ (SIPS) innovative process can help you enjoy the advantages of trenchless technology? Then, fill out our Pipe Lining Questionnaire today to get a quote for your project.