Non-destructive testing of water and sewer force mains

[SWRGRL]

Frequent listener first time caller...

Does anyone know of any NDT technologies for inspecting ACP/PVC water or sewer force mains that don't require bypassing? I'm aware of acoustic methods for DI and CI but I can't seem to find anything for non-ferrous pipes.

All commments/suggestions are appreciated.

 

[rconner]

I was hoping someone more knowledgeable and with direct experience could help you, but I see this has not occurred in all these many days! Would it perhaps be possible, e.g. with existing valves, bypass piping or during a shut-down period etc. to bulkhead off and hydrostatically test the pipelines involved (e.g. at a high enough pressure to maybe at least give some sort of feel for the pipeline and future needs?) If the line does not blow up but leaks, perhaps leaks could be located as in new construction (though I understand leaks are generally much harder to find with non-metallic)? Of course, there would probably need to be some sort of repair or contingency plans in case line did blow up in high-pressure testing! There are also now specialty testing firms that advertise ability to find even quite small leakage (that might not be easily found from the surface particularly with pipes that don’t carry sound well) by various means including passing devices through the length of the pipelines, but I suspect this may not be cheap.
Finally, as various soil conditions and/or contamination can degrade both types of pipes you talk about e.g. from the outside, perhaps you could consider some physical potholing or other daylighting to examine/peck on? outside wall conditions in areas? I would however caution that these kinds of pipes can be hard to locate, and perhaps particularly even dangerous/vulnerable to excavate/work around for this and other reasons, and of course all utility and OSHA rules etc. should be complied with in this regard.

 

[dicksewerrat]

you have to have the flow of the pipe to inspect, pressuretest or use some type of laser profiling for the interior of the pipe. If you have xray vision, you don't have to dig up the pipe to inspect the outside. So the answer is no you cannot inspect the inside of a pipe without bypass pumping.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[SWRGRL]

rconner we're trying to find pipe defects without high pressure-testing to minimize property damage in densely-populated areas. While soil testing would be very helpful for water mains (I'll look into this), we're also interested in detecting hairline fractures, blockages, and internal corrosion in ACP forcemains.

dicksewerrat, we were looking into Sahara and Smartball, which can inspect pressure pipes while in service (w/out bypassing or dewatering) but the examples I've found only seem to refer to DI/CI pipe.

Thanks for your comments though. From my conversations with operators/utilities, no-one even bothers to inspect unless there's a major failure and that's what we're trying to avoid.

 

[rconner]

Sahara and other systems of PPIC are one of th ecompanies to which I referred (I had thought they had reported experience with many types of pipes?)

 

[dicksewerrat]

If these companies can look at wall profiles with flow in the pipe for ductile and cast, they should be able to look at AC ppipe. What kind of report do they generate? Pipe ovality? do they give a profile of the pipe through 360 degrees? Can they show where the pipe wall has corroded? Have them bring you an actaul report and then call the client. I haven't heard of either company.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[rconner]

It is my understanding Sahara and Smartball (that I'm sure can easily be Googled) are means of finding leaks in pipelines. While I'm not sure they can do much more with regard tothe other aspects you're talking about (perhaps other than help focus other investigation?), they would appear to be one of many tools available for pipeline assessment.