In-place pipe restoration?

[willis]

Hello all, I would like some feedback on the in-place pipe restoration from someone who has maintained a plumbing system after this has been done. I work at a California University, and maintain a 50 year old, 6-story library that is in dire need of a re-pipe, and management seems to be sold on this process. Here is a link to a similar contractor/process. Any feedback, positive and negative would be greatly appreciated.

 

[Metalguy]

Where's the link?

 

[willis]

http://www.ampipelining.com/process/process3.html

Sorry 'bout that.

 

[Metalguy]

I took a look-sounds reasonable. We had considered using a similar process at a large plant I worked at, but I left and don't know if it was used.

For what it's worth, clean and dry application is the secret of sucess with epoxy coatings, as is proper mixing. I have 2 exoxy fillings in my front teeth that have been there since 1952!

 

[pmover]

some thoughts:

the process described at posted link appears to be an internal coating to pipe to prevent further corrosion. It does not address pipe integrity matters (i.e. amount of pipe wall thickness after corrosion). If the pipe metal is corroded and the current pipe wall thickness does not meet current design pressure requirements, then pipe replacement may be warranted.

If the issue is preventable corrosion, then it appears to be worth pursuing. I've personally applied an expoxy coating to the internal side of exchanger heads (used in refrigeration units) to prevent further corrosion (within 2-years of service, there was corrosion and pitting present). I cannot expand on the long-term success, but short term (i.e. 2-years) it did prevent further corrosion.

The comment about reduced pumping power may be valid as the pipe resistance to flow is reduced. Request that actual numbers (i.e. pump inlet/outlet pressures, motor current, pump flow data-if available) be provided before and after application of internal coating at some location. The difference will provide some economical numbers regarding operational costs.

What should be addressed is how much of the metal wall thickness is left, as the wall thickness determines (plus pipe material) the allowable pressure. If less than design, then pipe replacement may be warranted.

Address the pipe integrity matter first (if the pipe is corroded with reduced wall thickness, then failure of whole system could be more costly than the taxpayes want to know about) and then the internal coating, with economics.

-pmover

 

[willis]

Thanks for the input so far. I firmly believe that a re-pipe is in order, because the pipe is so degraded system-wide, but I am having a real hard time of convincing management of this. I have asked about pinholes that have clamps on them, he said that those pieces will be replaced with copper, which will introduce a transition fitting that we'll have to deal with in the future. There are pinholes all over. I am not at all sold on this, maybe someone who has had a good experience can convince me otherwise. If someone has had a bad experience, it may help me sway managements opinion. Thanks again for the post's.

 

[Metalguy]

Hasn't anyone cut out a section or two of the leaking pipe and looked at the inside? You need to determine if you have a pitting problem (primarily) or general corrosion. If it's just localized pitting, the epoxy can do it. But perhaps not otherwise, as pmover points out.

Guess I has "ass-umed" this was simply a pitting problem.

 

[willis]

I re-piped the 1st floor restrooms over the summer, and the pipe that I removed was tuberculated badly on the hot and re-circ lines, pitted on the cold.

 

[Metalguy]

OK, so then I guess you don't have much of a leak problem except on the cold piping, right? I'd still cut a few sections of pipe up and measure the wall-loss in general.