It’s now 5 decades since pipeline repair was revolutionized by the Cured-in-Place Pipe (CIPP) solutions. The technology has many advantages, chief of which is the ability to do repairs without digging up the soil. This reduces repair costs and time, as well as poses minimal effect on the environment.
However, like many other construction technologies, CIPP has some limitations. Before discussing the limitations, a brief description of what the CIPP technology entails will be good enough.
What Is CIPP?
This is a trenchless repair method used to rectify damaged existing pipelines. Instead of excavating the overburden to access the damaged section, a resin-saturated polyester felt tube is inserted into the damaged section of the pipe through a clean-out access point by the use of air pressure.
Once the liner is fully in place, it’s inflated to press against the inside walls of the pipe and then cured using either hot water, steam, or UV light. The result is a perfect pipe within a damaged pipe. This purportedly extends the life of the pipe by more than 50 years.
Though the process is this straightforward, you can come across the following limitations when doing pipelining:
- Curing Technicalities
For the CIPP lining to cure properly, you need to maintain constant high temperatures within the pipe for the resin to be properly set. If the resin doesn’t cure properly, the damaged part may not be properly sealed and may continue leaking.
The very first curing agent to be used when the technology was invented was hot water. And it’s still a reliable curing technique, though other companies have branched into steam and UV curing.
As such, for hot water curing, a mobile hot water curing system can increase your team’s productivity. When shopping for one, consider features like:
- Combined heating system and recirculating pump in one unit: This makes it easily portable and usable in areas with working space limitations
- Tankless water heater: You don’t need to carry an entire tank everywhere when you have a CIPP repair contract. As long as there’s a water supply in that area, you only need a hose to supply water to the heater and thereafter direct the heated water into the pipe under repair.
- Propane-powered: This is a great option since propane burns clean and is environmentally friendly.
- Pipe Run Complexity
CIPP works best for straight sections of pipe with no fittings, bends, and tees. When these are in plenty at the section being repaired, it may be difficult to achieve a consistent lining. You see, the lining has to be cut before a tee and start again after the tee. This leaves a gap in the pipe, which may expose the damaged section to further deterioration.
Furthermore, you may end up with lips and pits where the lining stops, and these may act as clogging points for waste and debris flowing within the pipe.
In such instances, it’s best to replace the pipe rather than line it internally. But if CIPP is the most viable solution, you may have to line the entire pipe and then cut out holes where there are connections. Just ensure that the cutouts are even and not over-cut or under-cut, as such inconsistencies can cause clogging.
And for pipes with bends, you may want to use liners made of woven fabric so that they navigate the bends without significant wrinkling.
- Smaller Diameter Pipes
Design standards expressly state that CIPP can be used for pipes with diameters between 2 inches and 110 inches. That’s theoretically true, but it may be technically difficult to repair pipes with diameters smaller than four inches. Pulling the resin-filled lining through a small diameter pipe requires exceptional technical know-how.
Also, the lining might significantly reduce the internal diameter of the pipe if it’s already very small and therefore interfere with the flow capacity. In such instances, you may want to consider other repair techniques such as cut out and replace, bypass, weld deposition, metallic sleeves, and reinforcement by rope.
- Environmental Pollution
For buildings constructed more than 40 years ago, you may need to do extensive testing to determine whether there is any lead or asbestos-containing materials before disturbing any materials. If these are detected, you’ll need to hire the services of a professional asbestos handler to reduce the risk of poisoning.
Also, it’s in your best interest to check with the manufacturer how toxic or safe the CIPP resins are before use. There have been cases where the washing of such resins downstream has killed thousands of fishes.
There’s also a possibility of the emission of volatile organic compounds during CIPP installations. Inquiring about all these issues with your CIPP contractor will help a lot in realizing your workforce wellness and consumer safety.
CIPP is very useful in pipe repairs, but there are some few limitations you may experience when doing pipelining with this method. Fortunately, there are proven workarounds to these limitations. Where there are no viable solutions, you can opt for other methods of pipe rehabilitation.