Advanced Construction Products
We have not seen any indication that our rerounders reduce the pipe integrity. We have seen testing that indicates that if the deflection is greater than 30%, the initial deflection can cause permanent structural damage. In all of the rerounding projects that we have been directly involved with, the deflections encountered have been less than 30%.
The rule of thumb that we use for checking excessive deflection is to pull the next size smaller deflection gauge through the pipe. For example use a 6 inch gauge in an 8 inch pipe. If the 6 inch gauge does not go through, then the integrity of the pipe should be evaluated. In our experience, that much deflection would be rare.
In the rerounding jobs that we have done there was no damage to the pipe or fittings. We are not aware of our customers damaging pipe or fittings. If any of our customers have, they have not brought it to our attention.
We have encountered a number of jurisdictions that do not allow rerounding. In the cases that we have inquired about, the reason has been because of companies previously damaging pipe with some type of rerounding device. We have heard of damage ranging from shaving the inside of the pipe (the most common), to pipe breakage. This could be caused by the type of equipment they used, using excessive pulling force, or rerounding a pipe with debris in it. It is always important to make sure the pipe is clean before using any type of rerounding equipment. Some of these jurisdictions have allowed the use of our rerounders by submittals or demonstrations.
It can vary a lot. In most cases, the majority of time is spent getting set up. Usually there are just a few spots deflected and the line can be done in about 30 minutes after set up. We have seen cases where it goes hard all of the way and it could take 2 or 3 hours for one run, but these are uncommon. Occasionally difficult spots can be encountered that can take a considerable amount of time just to get through one area.
We are not aware of any jobs where the deflection has returned. Many of the jobs have been inspected a year later for warranty purposes without any problem.
Probably. It is unusual for the rerounder to not go through the line, if everything is set up and done properly. Often there is a reason if it doesn't go through. For instance, if there was a boulder setting directly on the deflected area, the rerounder would not go through. If there was a thick layer of granular material between the boulder and the deflection, the rerounder would likely go through.
You will need something to pull it through with that can pull 500 to 2000 pounds of force, a pull line, a return line and a pulley where the pull line enters the pipe. You will also need a 75 CFM or larger compressor, a 3/4 inch minimum diameter air hose (lightweight PVC hose works ok), and our whip hose assembly that includes an air swivel, air filter and oiler. The vibrator causes a rotational torque, so we recommend a pull line swivel. The rerounder uses a separate concentric pull back swivel. If you plan on doing a lot of rerounding, a hose reel will speed up the process, even if it doesn't have a live swivel.
The depth of the pipe does not appear to be a problem. The rerounder has been used successfully at depths exceeding 30 feet deep.