Pipe Lining Systems: CIPP, Trenchless, Pull-In-Place, Air Inversion, Spray-On Epoxy, Pipe Bursting Explained
What Pipe Lining Systems Are Available?
It depends on the diameter of the pipe, the nature of fluid/gas being conveyed, pressure and heat inside the pipe.
Cured In Place Pipe (CIPP)
The vast majority of pipe rehabilitation in the United States uses cured in place pipe (CIPP) lining. Cured in place pipe lining involves inserting into the old pipe a long fabric tube or sleeve (typically fiberglass or polyester) that has been thoroughly saturated or wet out with a resin. Once the sleeve (or “liner”) is inside the pipe, it is inflated with water or air, and the resin is hardened using heat.
There Are 2 Ways The Resin Is Hardened (“cured”)
Exothermic chemical reaction – the resin may contain a catalyst that heats up the resin within 1-6 hours of installation. Supplying heat to liner – either steam or hot water may be pumped into the liner to harden the resin
What Kind Of Pipes Can Be Re-Lined Using CIPP?
Any pipes, vertical or horizontal, in the range of 0.5″ – 48″ can be lined using cured in place pipe lining. The limitations are diameter and the type of fluid in the pipe. For pipes larger than 48″, a spray-on epoxy pipe lining process is used. Various liner manufacturers have been approved for different kinds of pipes, based on the fluid the pipes convey. Some liners for example are not approved for potable drinking water pipes. Other liners may not be approved for pressurized pipes. Be sure to get written verification that the liner being installed is approved for your application. For example, just because a liner is approved by the National Sanitary Foundation (NSF), IAPMO and EPA, does not mean it can be used in fire suppression pipe lining.
Spray-On Epoxy Pipe Lining
First the pipes are sandblasted from the inside to remove all the old oxidation deposits. This is done by blowing air with entrained silica particles through the pipes. There is some “blowing” equipment upstream and “receiving” equipment downstream to capture the debris. Once the pipes are clean, air is again blown down the same pipe but this time along with an epoxy liquid that hardens in a few hours.
The epoxy used is the same food grade epoxy that you have seen on the inside of food cans, so it’s perfectly safe for consumption. This epoxy pipe lining is ideal for drinking water pipe lining, as it is very thin and very hard. But hard doesn’t necessarily make it strong, as it can crack under load-bearing applications, like under roads or wall footers. Generally epoxy pipe lining is used mainly in apartment, hotel and residential walls and floors, but not for sewer pipe relining.
But for situations where the pipe to be lined needs extra strength, regular drain lining pipe lining materials have to be used, such as the polyester and fiberglass felt impregnated with epoxy resin. These pipes are also usually of larger diameter, so the thickness of the liner has minimal effect on internal diameter reduction. This is called structural pipe lining (or just pipe lining).
Epoxy pipe lining is a pipe coating process that seals leaking pipes permanently. It prevents the need for repiping as it seals all copper pipe pinhole leaks from within the pipe. It also prevents lead from contaminating drinking water pipes from soldered pipe connections. Epoxy pipe rehabilitation is much less expensive than repiping and involves virtually no demolition in comparison. This type of pipe lining is usually used for water pipe leaks in pipes with 3/8”-4” in diameter.
Pull In Place Pipe Lining – Installation Method
First the pipe liner is wet out or saturated with the resin, and then the liner with its internal bladder is pulled into the host pipe using a winch or rope. Once in the correct position, the bladder is filled with air or hot water or steam, to harden the resin. This takes 1-4 hours, then he bladder is removed.
Air-Inversion Installation Method
Imagine taking a air-tight long sock and turning it inside-out inside the pipe, by blowing air or water into it. This method only requires only one access point, a huge benefit in some cases, such as under railways, highways etc.
Pipe Bursting Pipe Replacement
On some occasions pipes have to be rehabilitated by pipe bursting. Examples would be when the pipe is in too bad of a shape to be re-lined by CIPP or if the pipe diameter needs to be increased for more flow.
Concrete storm drains may be collapsing, corrugated culverts may be rusted and sagging, or clay sewer pipes may have off-set joints or partially collapsed sections.
Pipe Bursting – How It Works
First a strong cable is strung from one end of the pipe to another. Usually a watter jetter or pipe video inspection camera is used to pull the cable through the pipe.
Next a “pipe bursting head” is attached to the cable. A pipe bursting head is conical in shape, with the pointed end pointing towards the pipe. Behind the pointed end the new pipe is attached. On the other end of the pipe a very strong winch is attached to the cable, and the winch pulls the conical head and the new pipe into the old pipe.
Since the conical head is of larger diameter than the old pipe, the pipe bursting head breaks up and pushes apart the pieces of the old pipe for the new pipe to take its place.
What Happens To The Pipe Connections That Were Destroyed?
If there were connecting pipes, those connections have to be re-plumbed. This involves excavating where every connection was and manually reconnecting the old plumbing to the new plumbing.
Does The Pipe Bursting Destroy Part Of The Manhole?
Yes but the manhole is professionally repaired after the new pipe is in place.
Benefits Of Pipe Bursting Over Pipe Lining
First of all, the host pipe condition is not important. Any pipe can be pipe bursted. Secondly, the new pipe can be made to have a larger diameter than the old pipe, so flow can be increased. Thirdly, the new HDPE pipe is stronger than pipe lining. And last of all, the pipe does not have to be clean to be pipe bursted.