Don’t go CHEAP!

Ripped Material

I grabbed this picture from a video that was sent to me by an installer who was trying to find out why our lining material was ripping. This is the 3rd job that he’s had this problem and in each case the area was not the entire length of the liner but isolated to random sections. This one was in a 6” pipe. Of course the material is the first thing to blame but investigating causes usually identifies the issue causing the problem.

We capture samples of the materials we supply and can test materials shipped to any customer. But the first research is customer complaints from other installers to see if we have a material problem. As we’ve shipped thousands of feet of the same lot number of liner and thousands of pounds of the same lot numbers for the resin, we began to look at other factors.

The installer maintains that nothing changed in the past years since he’s been performing lining and is mixing resin properly per our instructions. In talking with the installer, we did uncover some differences in the process used in the field. The customer began using Kanneflex hose tubes to shoot the liner instead of his previous tank system he’d purchased from another supplier. You just attach a nozzle to the one end of the hose, stuff the material inside the hose and invert it through the nozzle. You attach the inverted piece of liner to the nozzle and place a rubber band on the other end of the liner. After it’s packed into the hose, place a cap with an air port and shoot the liner into the old pipe. The 6” Kanneflex hoses may not be able to store enough air that you would find in the tank nor have big enough hoses to provide volume if using a larger air compressor especially if you pack the tubes full of liner material. When filling too much liner and unregulated air volume/pressure, you set yourself up for inverting the liner at a pressure too great for the lining material to resist ripping. In this case the liner inverted due to high pressure and the speed at which it went in but didn’t remain a solid tube. The calibration tube followed, curing the liner over the ripped section and leaving a nasty gap in the pipe. 

We see many folks using this system as it’s cheap to accumulate parts and make an inversion device but the trade-off is the risk you take in doing it. Especially if the liner stops and the operator builds pressure higher and higher to get the material to move again. If your air compressor has a top setting of 130psi, then building this much pressure puts the liner right up to that pressure as it finally moves due to the extra pressure and ripping the material as it does so. The second risk is the danger of running too much pressure through Kanneflex hose. It’s rated at about 80psi and if the nozzle isn’t properly maintained it can fly apart striking a worker causing severe injury or death. While tempting to opt into a cheap method to invert liner the risk may outrun the reward.

Quik-Shot™

Most inversion machine manufacturers set a “not to exceed” limit as placarded on the device. We set our “not to exceed” limit on our Quik-Shot™ at 30psi. So the lesson here is reduce pressure and if your homemade device won’t work within the safe limits there are several suppliers that can get you devices that will work. For more information contact us at 888-354-6464 or info@pipeliningsupply.com.

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