# Pvc vent pipe



## paultheplumber1 (May 1, 2014)

Got these from my local inspector today. He says he can't stop me from using it yet but would rather I didnt. And that he's going to be pushing for the state to outlaw the use of pvc for flue gas.


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## ZL700 (Dec 8, 2009)

Good luck to your inspector. 
Never does it say don't use, it just states ASTM approvals don't cover combustion venting applications.
Many misinterpret this letter, its just a release of liability from Charlotte as the PVC used in venting is under approval as a vent from another agency (CSA)that is involved as venting as a system and not covered by ASTM. 

Follow the directions in the installation manual and use the appropriate materials in the correct situations and there ARE NO PROBLEMS. Unfortunately because installers can't do this there are those situations that causes PVC to come into question. One alternate is Polypropylene, and it can be installed improperly also. 

As it states:
"Equipment manufacturers are most knowledgeable about their own products and are best-equipped to determine how their gas-fired heating equipment should be vented. 
Accordingly, Charlotte Pipe recommends that inquiries about the suitability of plastic piping systems to vent combustion gasses be directed to the 
manufacturer of the water or space heating equipment being installed."


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## paultheplumber1 (May 1, 2014)

There are 2 towns in the state that allready do not allow us to use it. They do allow us to use CPVC for the flue gas and PVC for the fresh air intake. It's starting to become a major Pain in the butt. In my experience arguing with the inspector is usually not in my best interest. The man who handed me these papers is well respected in the state and has held a seat on the state Board for a long time. Basically this is going to happen here.


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## ZL700 (Dec 8, 2009)

Paul,
You didn't mention the application but there are certainly reasons not to use PVC Sch 40 as a vent material.
The problem usually lies in when its not allowed per manufacturer but its still used.
Perfect example is on a boiler operated at 180 degrees- def a nono. 
Banning its use would be an overreaction to understanding the difference or unable to enforce different uses and application allowances. 

But that would be along the same lines of ignorance inspectors show towards tankless for example. Requiring 18" of non plastic at the water connections. They don't seem to realize that there is no draft hood on the bottom of a tankless and be it 2" or 20" the pipe will always be the same temp (the outlet water temp setting).


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## paultheplumber1 (May 1, 2014)

Today there was no specific application. He was just making me aware of the possible changes coming. He's a good guy like that. He hand delivers all code updates to my office as soon as he gets them. However I have been told I cannot use it on an on demand water heater and the AC guy was told he cannot use it to vent his hot air furnace.


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## Plumbus (Aug 4, 2008)

This is a Catch 22. The appliance manufacturer says use PVC. The PVC pipe manufacturer says don't. If you have a pipe failure, you are on your own. I'd use CPVC or some other approved pipe.


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## ZL700 (Dec 8, 2009)

Plumbus said:


> This is a Catch 22. The appliance manufacturer says use PVC. The PVC pipe manufacturer says don't. If you have a pipe failure, you are on your own. I'd use CPVC or some other approved pipe.


Nowhere is it written "don't"
That continues to be the biggest misconception and misunderstanding.


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## ZL700 (Dec 8, 2009)

paultheplumber1 said:


> Today there was no specific application. He was just making me aware of the possible changes coming. He's a good guy like that. He hand delivers all code updates to my office as soon as he gets them. However I have been told I cannot use it on an on demand water heater and the AC guy was told he cannot use it to vent his hot air furnace.


 Sch 40 PVC has been used on condensing furnaces since 1982?

Fact is the poly pipe reps are the ones promoting the sale of their products through scare tactics yet there is no reported failure yet of properly installed PVC on an appliance that allows its use. And is one of or only at one time acceptable vent material by many manufacturers.


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## Plumbus (Aug 4, 2008)

I realize PVC has been used for a long time. I've been using it ever since we started to run into condensing appliances (and I'm still using it). However, I sat in on a code meeting called specifically to address this question. One guy from Charlotte and another from Spears who were in attendance both said they do not warranty their PVC pipe and fittings for flue applications.


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## ZL700 (Dec 8, 2009)

Plumbus said:


> I realize PVC has been used for a long time. I've been using it ever since we started to run into condensing appliances (and I'm still using it). However, I sat in on a code meeting called specifically to address this question. One guy from Charlotte and another from Spears who were in attendance both said they do not warranty their PVC pipe and fittings for flue applications.


Warranty?

What's the warranty on 26G galv vent pipe connectors and elbows? - none of course

Gas fired boilers and water heaters are required to be safety certified by a third party testing agency according to the American National Standards/CSA Standards. Boilers are design certified to ANSI Z21.13/CSA 4.9 and commercial water heaters are design certified to ANSI Z21.10.3/CSA 4.3. As a part of this certification, the appliance must undergo tests to assure the specified venting system is appropriate for use with the appliance. Each standard includes specific test procedures for Non-metallic venting like PVC/CPVC. The appliance is placed in a closet and the water temperatures are raised to the highest permissible level. This generates the highest flue gas temperatures. Under these conditions, data is collected to verify the vent material’s temperature limitations are not exceeded. The vent tests measure the actual pipe material temperature, not the flue gas temperature to determine the effect of hot flue gases on the vent material. ANSI test procedures are under constant review by the ANSI standards committees to assure the test conditions are appropriate and up to date.

Again inspectors only know what their told from parties that have an interest. If they knew and understood the full realm of the requirements of their jobs and the appliances they are charged with inspecting, which includes more than one or two agencies, they'd have a better grip on their authority.


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## Plumbus (Aug 4, 2008)

Nice boiler plate. But, code says, when in doubt, the installer and AHJ should consult the appropriate manufacturer's installation instructions. However, that is not the point I wish to make.
In our litigious society it's not inspectors who we plumbers need to be wary of. If a failure were to occur, everyone exposed would be abandoning ship, including our insurance carriers if the sharks can convince a judge or jury that we used a product of questionable approval. Maybe this is a black and white issue to an engineer, but there are no guaranties those colors would be found in a court of law.


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## plumbdrum (Nov 30, 2013)

ZL700 said:


> Warranty? What's the warranty on 26G galv vent pipe connectors and elbows? - none of course Gas fired boilers and water heaters are required to be safety certified by a third party testing agency according to the American National Standards/CSA Standards. Boilers are design certified to ANSI Z21.13/CSA 4.9 and commercial water heaters are design certified to ANSI Z21.10.3/CSA 4.3. As a part of this certification, the appliance must undergo tests to assure the specified venting system is appropriate for use with the appliance. Each standard includes specific test procedures for Non-metallic venting like PVC/CPVC. The appliance is placed in a closet and the water temperatures are raised to the highest permissible level. This generates the highest flue gas temperatures. Under these conditions, data is collected to verify the vent material’s temperature limitations are not exceeded. The vent tests measure the actual pipe material temperature, not the flue gas temperature to determine the effect of hot flue gases on the vent material. ANSI test procedures are under constant review by the ANSI standards committees to assure the test conditions are appropriate and up to date. Again inspectors only know what their told from parties that have an interest. If they knew and understood the full realm of the requirements of their jobs and the appliances they are charged with inspecting, which includes more than one or two agencies, they'd have a better grip on their authority.


I've got all the grip I need, I just approve what the manufacture put in their installation manual and I've got clear conscience on my decision That manufacture has to go through our state board for Product Acceptance if they want to have their appliances installed in this state. Installers just need to read the freakin installation instructions. That Charlotte letter has been around for years, they're just covering their azz . If the venting system should fail the blame lies on the installer or the inspector ( if it was inspected) for not installing it properly, not the pvc manufacture.


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## Plumbus (Aug 4, 2008)

Here's another engineer's take on this issue.
http://plumbingengineer.com/content/pvc-acceptable-vent-material-flue-gases


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## Plumbus (Aug 4, 2008)

plumbdrum said:


> If the venting system should fail the blame lies on the installer or the inspector ( if it was inspected) for not installing it properly, not the pvc manufacture.


Perhaps you are right, or not. 

Ron George is know for his dry copy, but he is nothing if not thorough.
http://plumbingengineer.com/content/pvc-acceptable-vent-material-flue-gases


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## plumbdrum (Nov 30, 2013)

Plumbus said:


> Perhaps you are right, or not. Ron George is know for his dry copy, but he is nothing if not thorough. http://plumbingengineer.com/content/pvc-acceptable-vent-material-flue-gases


I'll be sleeping just fine.


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## Plumbus (Aug 4, 2008)

plumbdrum said:


> I'll be sleeping just fine.


Like I said earlier, I still use PVC to flue condensing appliances and my sleep patterns are governed by my bladder and not concerns about failed flue pipe.


This issue has been hashed out on other forums.

From an installer's perspective
http://forum.heatinghelp.com/discussion/136409/is-pvc-an-acceptable-vent-material-for-flue-gases

and an engineer's perspective
http://www.eng-tips.com/viewthread.cfm?qid=331089


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## paultheplumber1 (May 1, 2014)

I just wish somebody would make a decision yes or no. I agree with the fact if properly installed the PVC will be fine. Has been for a long time now. It has started to become an issue when more and more code officials are outright refusing us from using it. The price jump to the next higher up material is significant enough to make or break a simple replacement job. And I have had to remove a job I did with the pvc and replace it with CPVC and the CO of the job was held up until the HVAC contractor and myself conformed to the code officials request. I only posted this to share that it does not matter what I think or what the man specs say. And one more town in my tiny little state is on the move trying to not allow the PVC to be used.


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## ZL700 (Dec 8, 2009)

Plumbus said:


> Here's another engineer's take on this issue.
> http://plumbingengineer.com/content/pvc-acceptable-vent-material-flue-gases


I know of Ron, more than most

What most don't know at the time of this writing both in May of 2013 & 2014, he was attempting to get a patent on a PVC vent combustion temp safety device with the intention of making it a mandatory item.
Which he was unaware, at the time tankless for instance already has this.

Purely money motivated, smart guy but shortsighted in his article.
Also if you didn't know the ULC-636 that he speaks of in Canada as a code, is just PVC and CPVC at 5X the cost to a contractor.


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## ZL700 (Dec 8, 2009)

Plumbus said:


> Nice boiler plate. But, code says, when in doubt, the installer and AHJ should consult the appropriate manufacturer's installation instructions. QUOTE]
> 
> Exactly what I stated in post #2 and mentioned in the Charlotte letter


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## Plumbus (Aug 4, 2008)

ZL700 said:


> Plumbus said:
> 
> 
> > Nice boiler plate. But, code says, when in doubt, the installer and AHJ should consult the appropriate manufacturer's installation instructions. QUOTE]
> ...


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## GAN (Jul 10, 2012)

As an inspector for going on 30 years, you learn that you "do learn" everyday.

I agree with Plumbus, It is not the Inspector who is qualified to judge what materials can be used. It is our job to assure a manufactures installation was followed. Ben down that route with engineers.

Of course keep an eye out for potential health or safety hazards and bring attention to them. Then let the higher payed, ones with degrees fight it out.

If you are an AHJ, best not use the "I want it that way" excuse. Either exempt it in a code adoption by your municipalities board. If not when and if you get challenged you will loose.


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## plumbdrum (Nov 30, 2013)

GAN said:


> As an inspector for going on 30 years, you learn that you "do learn" everyday. I agree with Plumbus, It is not the Inspector who is qualified to judge what materials can be used. It is our job to assure a manufactures installation was followed. Ben down that route with engineers. Of course keep an eye out for potential health or safety hazards and bring attention to them. Then let the higher payed, ones with degrees fight it out. If you are an AHJ, best not use the "I want it that way" excuse. Either exempt it in a code adoption by your municipalities board. If not when and if you get challenged you will loose.


Bingo


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