Measuring HDPE Pipe Thickness In-situ 1

[Brent Boisvenue]

We have just dug up a supply and return line feeding tailings from a mill to a hydraulic sandfill plant. Drawings indicated 20" steel rubber lined pipes, but after digging them up, we found they are actually HDPE. Of course, there is no documentation of the change from steel to HDPE. We need to tie into these lines as part of the plant upgrade, but we need to determine the thickness of the line to figure how to tie into it (preferably before we cut the flow and cut the lines). The line is still actively used.

We talked about using ultrasonic measurement, but we have nothing to use as a baseline to calibrate the instrument (we don't know what brand or specs for the HPE pipe). We figured we might be able to calibrate off of a known HDPE pipe spec and use it as an "estimate" to try and correlate the measurement to a nominal thickness. This would only produce an estimate, since we don't know the brand and; therefore, the density of the existing material. The other idea was to drill a small hole and physically measure the thickness, then tap and plug it (all while in service). Not sure about the latter.

Someone also suggested a bell and spigot connection for independence from the ID. However, I'm not sure that exists for 20" un-corrugated HDPE pipes.

Any recommendations?

 

[LittleInch]

HDPE pipe often has the data stamped or stencilled into the pipe. Try and expose a decent length and find out what the joint system is and see if there are any marking on a 12m section of pipe.

Hopefully it is fuse welded together. You might be able to remove a section of the weld bead if they didn't do it in the field to get you a sample to test for strength if nothing else.

But why do you need to know? You can fuse saddles or half shell tees onto the lines before you cut into them. Most external fuse work on the OD of the pipe and the thickness doesn't really matter.

Oh and measure your pipe to get the correct OD - PE pipe comes in different sizes from Iron or steel pipe. So measure the circumference accurately and divide by 3.14195

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Brent Boisvenue]

Thanks, we will be measuring OD. Never thought of looking for markings on pipe. I'll see if our client can check the excavation.

 

[1503-44]

3.14159

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[LittleInch]

Smart arse....

It might not be as clear as this but it is very common - you might need to wash the pipe to find it and it's more common at the ends of the pipe.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Have you been using 3.14195 for all these years?

A black swan to a turkey is a white swan to the butcher ... and to Boeing.