Thread: cpvc tpr discharge pipe

When cpvc is used for the TPR discharge pipe, is it required to be labeled for that application?

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Originally Posted by John Arnold

When cpvc is used for the TPR discharge pipe, is it required to be labeled for that application?

Not that I'm aware of.

CPVC is an approved material for a discharge line. It does not need to be labeled '..approved for discharge line...' It only needs to be labeled 'CPVC'

Originally Posted by John Arnold

When cpvc is used for the TPR discharge pipe, is it required to be labeled for that application?

The other approved pipes are generally not labeled either, copper, galvanized, pex. There is however a discharge pipe sold at plumbing suppliers that is labeled for that use.

Originally Posted by Chris Weekly

CPVC is an approved material for a discharge line.

Whoa there! That's a blanket statement that is not completely correct. Our state, for one, requires the extension to be a metal pipe.

As Johns tag line says - There is no exception to the rule that every rule has an exception. - and in this case the exception is "local codes notwithstanding".

I didn't think about having to throw in exceptions, knowing that they loom behind darn near every statement.

Our State allows it, but larger cities do not.

CPVC is allowed under the IRC ( 2803.6.2 )and the UPC ( 608.5 ) - with the same materials that are allowed for water distribution eg. hard drawn copper, galv. and CPVC.
There is no requirement for any of the above materials to be labelled as discharge pipes for the TPRV.

Adapting to same from the relief valve itself can prove difficult. Threaded CPVC must be Sch. 80. Connections thereafter not allowed to be threaded. Transitions to other materials and for the Discharge piping itself (until transitioned to drainage and/or exposed to atmosphere for pressure equalization and release of energy) must be able to withstand both temperature AT pressure.

Originally Posted by Chris Weekly

I didn't think about having to throw in exceptions, knowing that they loom behind darn near every statement.

It's why you gotta be careful writing reports and talking with client's - for me it takes real concentration to avoid slip ups. Even so, people will often hear what they want to hear.

Originally Posted by H.G. Watson, Sr.

Adapting to same from the relief valve itself can prove difficult. Threaded CPVC must be Sch. 80....

So, I should be checking that the threaded adapter is Schedule 80?

Originally Posted by H.G. Watson, Sr.

Threaded CPVC must be Sch. 80.

Originally Posted by John Arnold

So, I should be checking that the threaded adapter is Schedule 80?

John,

I believe Watson was saying that CPVC pipe which is threaded must be Sch 80.

Ever look at the wall thickness for CPVC or PVC pipe? Can you imagine trying to cut threads into the much thinner wall of Sch 40? The die would probably cut all the way through the walls and about all you would succeed in doing is making the pipe shorter ...

Originally Posted by Jerry Peck

John,

I believe Watson was saying that CPVC pipe which is threaded must be Sch 80.

Ever look at the wall thickness for CPVC or PVC pipe? Can you imagine trying to cut threads into the much thinner wall of Sch 40? The die would probably cut all the way through the walls and about all you would succeed in doing is making the pipe shorter ...

Thanks. The way it was written made it sound like it was problematic that threaded cpvc had to be schedule 80.

Originally Posted by John Arnold

Thanks. The way it was written made it sound like it was problematic that threaded cpvc had to be schedule 80.

"threaded cpvc had to be schedule 80"

Threaded CPVC and PVC does need to be Sch 80.

Keep in mind that is referring to threaded "pipe". Fittings are another matter and fittings have to meet their own requirements.

Originally Posted by Jerry Peck

... Fittings are another matter and fittings have to meet their own requirements.

Ok, now I'm really confused. Let me start over.

Watson's wording seemed to me to be saying that adapting cpvc to the tpr valve, which is accomplished with a threaded fitting, can "prove difficult" because said fitting must be schedule 80, as if some installers used fittings that were not schedule 80. I guess I was wrong about that.

So, what, exactly, makes adapting cpvc to the tpr valve "difficult"? It seems pretty straightforward to me. You do it with a cpvc threaded fitting, which, by the way, happens to be schedule 80.

Originally Posted by Eric Barker

It's why you gotta be careful writing reports and talking with client's - for me it takes real concentration to avoid slip ups. Even so, people will often hear what they want to hear.

...and I agree.....and, that's why it takes me 4 hours (or more) to write up a report on a house that takes me 3 to 4 hours to inspect. I know the report writing takes longer than the inspection itself because I want to make sure of what is being reported is what I want to say....in so many words..... but in as few words as possible. I take my time to write a concise and compact report. I have had many favorable comments on my reports.
Something like when Mark Twain said "I would write a shorter letter if I had more time."

Originally Posted by John Arnold

So, what, exactly, makes adapting cpvc to the tpr valve "difficult"? It seems pretty straightforward to me. You do it with a cpvc threaded fitting, which, by the way, happens to be schedule 80.

Nothing makes it difficult - you pretty well covered.

I'm waiting for Watson to poke his head in here now and say 'The problem with CPVC is that CPVC is *smaller* than the opening in the T&P relief valve and the opening is not allowed to be reduced in size.' ... I *hope* he is smarter than that ...