Old CPVC test

[phishfood]

I changed out a shower valve for a customer the other day. The CPVC on the hot side had a manufacture date of 1997.

So, with all of the mention of CPVC becoming brittle and failing over time, I think that it would be interesting to run a few admittedly unscientific tests on this pipe.

I am slammed with work right now, but I will update this thread as I go along.

 

[johnjh2o]

Were you able to cut it with CPVC cutters or did you use a hack saw?

John

 

[phishfood]

To be on the safe side, I used a hacksaw blade to make the inital cut. After that, I made a test cut with my ratchet cutters on the pipe that I had removed. It cut cleanly and without cracking.

 

[phishfood]

OK, I got a start on this project this afternoon.

Here is the torture subject. I called Dick Cheney, he said that this is definitely a bad guy, and cleared me to proceed with enhanced torture techniques.

Edit:OK, an invalid file on the upload. Let me see what I can do.

 

[phishfood]

Ok, here are a couple of pictures of the pipe showing the date.

 

[phishfood]

These are pictures of the solvent cement joints in the test section.I am not sure of the one, it almost appears to be clear PVC glue with purple primer. The other seems to be Orange CPVC glue with purple primer.

 

[phishfood]

Here it is with a test and fill rig on one end, and a ball valve on the other end.

 

[phishfood]

There it is with just under 300 psi on it.


And after half an hour.


The drop in pressureis more than likely due to the pipe stretching. The test system is so small, with no air trapped in it, any small change in volume will figure in the pressure. This is after half an hour.

 

[Makayla]

I appreciate it.

 

[phishfood]

What do you appreciate about it, Makayla in San Jose, California?

 

[Chris]

She appreciates the quality of the old CPVC Pipe.

 

[Otahyoni]

I'm curious how you got it to 300 psi...

 

[Chris]

A hydrostatic test pump?

 

[Chris]

Speaking of 300 psi, isn't cpvc glue only rated for 140 psi?

 

[Otahyoni]

Maybe for extended use.

It can handle 300 psi......once

 

[phishfood]

A properly made solvent cement joint on CPVC is stronger than the pipe itself.

I have seen videos where a CPVC assembly was pumped up until it failed. The pipe blew or a chunk blew out of a fitting, never was it the glue joint that failed.

 

[IFIXH20]

I changed out a shower valve for a customer the other day. The CPVC on the hot side had a manufacture date of 1997.

So, with all of the mention of CPVC becoming brittle and failing over time, I think that it would be interesting to run a few admittedly unscientific tests on this pipe.

I am slammed with work right now, but I will update this thread as I go along.

Was the piping in a interior or exterior wall -- just curious

 

[phishfood]

Outside wall, plywood and stucco.

 

[protech]

pressure testing brittle pipe proves nothing. Try bending it or freezing it.

Here is a more accurate test that simulates real world conditions:

pressurize, then apply pressure on the joints (mimics thermal expansion cycling).

Do the same with a new piece of pipe shaped the same way.

Increase the stresses placed on both pipes equally.

Impact testing would be another good one as a good portion of the cpvc repairs I do are from torsion or impact (think kid yanking on a hose bib, water hammer, cable guy stepping on pipes in an attic)

 

[phishfood]

Good point.

I will see if I can come up with a "under pressure" stress test for it.