Which is the best option, Pull-in-Place or Inversion?
Pull-in-Place or Inversion?
While I was overseas, someone said to me: it sounds like you ran into salespeople excited about selling their systems to you without educating you about their processes, as well as what other systems that are out there and how they work.
Let’s start with the basics: both inversion and Pull-in-Place systems are approved for using CIPP lining to rehabilitate pipe here in Australia.
The Inversion and Pull-in-Place methods found in the Australian WaterMark Standards describes the means and methods to install CIPP. Either method can meet the standard to give the customer a 50-year design life, chemical resistance, and durability to provide a new pipe inside the old pipe, the old pipe serves as little more than a host for the new pipe.
To be clear, the effectiveness of either method to deliver a liner inside the pipe, which is strong or to prevent roots growing back into the pipelines are exactly the same. To dismiss one method over the other is simply a personal preference, which is not based on the WaterMark standard for effectiveness. Relying on one method over the other will result in you not being able to compete on all jobs competitively.
Here are some pros and cons of both systems:
The Inversion Method:
The investment in equipment to install it can be very expensive.
It is performed by saturating the tube with resin inserting it into a device (Inversion Drum or Extruder) that turns the material inside out as it is installed into the pipe or inverted.
It may be installed through only one opening, usually but not always an excavated point, shooting to a stopping point without digging up or accessing the other end.
This method is used as installation lengths may be longer than the pull-in-place method, but not always. The reason is that the friction found in the pull-in-place method is higher, with inversion if you have enough air capacity, you can install virtually any length you need.
Lining over any junctions will require them being reinstated which takes time.
The Pull-in-Place Method:
The investment in equipment to install it is much less expensive as there are only a few parts needed to install.
It is performed by saturating the tube with resin inserting it onto a bladder system and pulling it into place.
You usually need to have two ends open but not always, it can be pushed into place with one access if required.
While it can be said that long lengths 25 metres or more are the forte of inversion, the precise pinpoint placement of a liner with pull in place is its forte.
You will usually get better results on more complicated pipelines (traps and multiple tight bends) more consistently with pull in place.
In summary, both methods have been used for years and are both proven to be acceptable. While I have mentioned some of the attributes of both systems, it is not a comprehensive review of either system – there will be many areas where one system will excel in preference to the other. The purpose of this overview is simply to point out the advantages of using both systems and many times they can be used together on the same relining job to give you a competitive edge.
So, here’s the important thing: we supply contractors who use both methods. Sometimes pull-in-place makes sense, especially with shorter lines where more complicated pipes are installed. Sometimes inversion works better when the lines are longer and need the ability to go further. If you have an inversion system, we can train you to employ pull-in-place so you can use it when you need it. If you have a pull-in place system and you want to own an inversion system, we will train you how to use an inversion system.