PVC Venting on boilers again!

HDE_2

<span style="font-size:12pt">Catching up on my past issues, I read an article written by Carol Fey in the April 2015 issue of </span>

<span style="font-size:12pt">Contractor Mag titled “Risk of using PVC for boiler venting”</span>

<span style="font-size:12pt"> </span>

<a href="http://viewer.zmags.com/publication/edffb9bc#/edffb9bc/19">[u][size=12]http://viewer.zmags.com/publication/edffb9bc#/edffb9bc/19[/size][/u]</a>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">Carol writes: </span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">“The manufacturer clearly states that their product is not for operating temperatures exceeding 140°F. What temperature could boiler exhaust be expected to be, even low temperature condensing boilers? It’s in the range of 250°F to 270°F. That’s exposing the PVC to operating temperatures much higher than the manufacturer specifies”</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">“When it comes to the risk of using PVC as venting is it worth it to save $3.00 a foot by installing PVC (about $1.50/ft.) instead of polypropylene (about $4.50/ft.)?”</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">I find this article not only misleading and confusing but downright incorrect. There were a lot of shots across the bow at about 90% of the boiler manufacturers that have products vented or have the capability of being vented with PVC/CPVC. First that 140°F pertains to a fluid temperature at 20 PSI, per PVC manufacturers. Since when does condensing boiler combustion venting have a significant vent pressure to be measured in PSI and a fluid? </span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">According to PVC Pipe and fitting manufacturers, PVC has the following ratings:</span>

<span style="font-size:12pt">Maximum Temperature: 158°F, 70°C</span>

<span style="font-size:12pt">Minimum Temperature: -13°F, -25°C</span>

<span style="font-size:12pt">Melting Point: 176°F, 80°C</span>

<span style="font-size:12pt">Tensile Strength: 6,500 psi</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">To my knowledge and please prove me wrong, the true PVC operating temperature limit on a combustion vent system is 149</span><span style="font-size:12pt">°F. And many boilers have the protection to not exceed that unless suitable venting materials are used. In addition it’s misleading in the article to state “PVC Manufacturers do not approve their material for venting”. The way I see it that falls under CSA and ETL as a venting system for approvals. The approvals that everyone wishes to cite when throwing sticks and stones at PVC for venting is ASTM. I got news folks, PVC manufacturers don’t write those standards, and it’s a plumbing product code approval. So how is CSA approval on PVC venting any different than ASTM approval on PVC plumbing?</span>

<span style="font-size:12pt"> </span>

<span style="font-size:12pt">The interesting part here as I have read Carol in this publication is a regional manager with Viessmann boiler. So we can see the purpose of the article but then there’s the more confusing aspect. She states that with flue temps of 250°F to 270°F, didn’t she just disqualify venting the boiler products she represents with the polypropylene materials they require? And lastly, where can you buy a section of 3” x 4’ polypropylene vent material for $18.00? </span>

ChrisJ

melting

Everything I've found states PVC melts @ 160C or 320F.



Where did you find 80C?

Steamhead

We've discussed this several times

and it usually comes down to the fact that most Codes require any material used for venting combustion products to be listed for that purpose, and the fact that PVC pipe manufacturers have not had their pipe listed for venting combustion products. And, given the high-profile lawsuits where PVC venting was involved, they probably never will.



We don't like the idea of paying lawyers, so we don't vent with PVC.

icesailor

Approved:

I was at a boiler venting class where the well known manufacturer stated to not use Sch 40 1094 pipe for exhaust venting but it was OK for air intake.  Sch. 80 CPVC was OK for condensing boilers that didn't have higher temperatures.  PP was approved in Canada at the time, and the boiler manufacturer sold a line of PP. But the compelling point was that no PVC pipe manufacturer listed their Sch 40 1094 PVC pipe for exhausting gas appliances, regardless what the manufacturer of the equipment said in the installation manual.

So I looked. No manufacturer stated that their pipe was approved by them for any product that was higher than 140 degrees.

ChrisJ

Interesting

The maximum service temperature for PVC is 140°F.



http://www.harvel.com/technical-support-center/product-specifications/pvc-pipe-schedule-40

icesailor

Reading Documents:

If you carefully read that PDF, they state that Sch. 40 PVC pipe is good for temperatures up to 140 degrees. Maybe that is for a drain, waste and vent.



No where in that pamphlet is there any mention of the pipe being used for exhaust vents of ANY appliance. Heating or otherwise. Charlotte doesn't.



The reason is that if the pipe manufacturers don't include that use, they don't approve it. If you use it and there is a problem, it will be between you and the appliance manufacturer that suggested using the PVC for venting. The PVC manufacturer is off the hook. They hope.

ChrisJ

Venting

However,



My Bradford White water heater specifically says for use with Sch 40 PVC.



http://s3.supplyhouse.com/manuals/1270752206645/28915_PROD_FILE.pdf

icesailor

Understand?????

Do you NOT understand???



The pipe manufacturers do NOT specifically approve of their product to be used as you want to us it. If there is any form of a problem, you are on your own. Just because the water heater manufacturer says that you can use it, only means that the water manufacturer approves it. Charlotte and others have no position. They do NOT specifically approve it.

If you use it, and the white plastic turns yellow or brown, and someone is injured, Charlotte will look at the pipe, see that it is yellow or brown, and tell you that you are on your own. Because regardless of whatever temperature you think it ran at, if the pipe turns yellow or brown, it has overheated and the chlorides were off gasses out.

Once the pipe and fittings leave the manufacturing facility, they don't much care what is done with it. As long as they were paid for it.They only cover what they have written in the approval.



Its like the Kerfuffle over Burnham oil boilers and replacing the oil burners with gas burners. Burnham doesn't approve it. It violates the UL listing. Will it work? Yes. Will Burnham warranty the boiler if the boiler starts leaking and the leak has absolutely nothing to do with the gas burner installation or operation, will Burnham honor the warranty? Not on your life. You used an unapproved product on their equipment, voiding any and all warranties.

Will PVC work on a condensing gas boiler or a gas direct vent water heater? Absolutely/ If the pipe fails, will Charlotte help you? Absolutely NOT. You used their product in a way that they didn't approve it to be used.



Its not the boiler manufacturers that are the issue. Its the PVC pipe and fittings manufacturers that are the problem. Use it at your own peril.

icesailor

140 degrees:

“The manufacturer clearly states that their product is not for operating temperatures exceeding 140°F. What temperature could boiler exhaust be expected to be, even low temperature condensing boilers? It’s in the range of 250°F to 270°F. That’s exposing the PVC to operating temperatures much higher than the manufacturer specifies”

 Notice in the article, she only mentions the 140degrees. No mention of what or how it is used. Look closely. As far as I know, that is the limit. The product isn't to be used with working temperatures over 140 degrees.

I did lots of Sch. 40 PVC venting. We all have. What is the exhaust temperature of HTP Munchkin boiler topping off an indirect where the high limit is at 170 degrees into an indirect? Its over 140 degrees. They all worked for years. Charlotte didn't approve the application.

KC_Jones

Read carefully

One thing I have learned in the corporate world is don't read between the lines.  That excerpt from your water heater manual is carefully worded.  It specifically says PVC AND vent pipe.  So here is the deal call up Charlotte (or any other PVC pipe manufacturer) and order some PVC boiler vent pipe and see what they say.  That product, according to them doesn't exist.  So the water heater manufacturer is basically telling you to use a non existent product, they way I read.  I think this is the same point that Icesailor is trying to make.  My car is powerful enough to burn the tires off to the point they would explode, if i do that and someone gets hurt is the car or tire manufacturer going to do anything for me?  No because I used the product "in a manner other than intended".  Not the greatest analogy, but I think you get the point.  To me the bottom line is use approved materials specifically designed for the application someones life could depend on it.  Over the course of your life you will end up making and spending 100's of thousands if not millions of dollars on "stuff" so what is a couple extra for proper venting?  Just my opinion.

Tim McElwain

I have written several

articles on this in the past in several different trade papers. If you are interested I can make them available for reading by you contacting me at gastc@cox.net.



You use PVC and CPVC at your own risk as an installer and you are fully liable for any failure. No one will show up in court to bail you out that is for sure.

icesailor

TV Game Shows:

To both KC & Tim:

DING-A-LING, DING-A Ling!!

Sound of a winner on a TV Game show.

You just correctly answered the big money question.

Congratulations.

The manufacturer will use a defense. "Not used in a manner approved or listed by the manufacturer."

With the Law, there are no guesses, no suppositions. Either Yes, or NO. No Maybe. Unless the "Maybe" is to one side. Then, the other side complains.

ChrisJ

Actually

What I see is "Properly sized PVC, CPVC or ABS* pipe must be used."



To me, that means if I use something other than those materials I would be liable.

icesailor

Turning Tires:

Great analogy about the tires.

Just imagine:

I have a friend who when before he was married, he had a 1959 Chevy. One day, Back in the Mid 1960's, he had a rear brake line rust out and leak. Being the ingenious Yankee that he was, he climbed under the car with a hammer and beat the brake line flat so it didn't leak fluid. He then discovered that if he held his foot on the brake pedal, he could stop the good rear side and the differential would allow all the power to go to the other side. "Lighting up" the other side tire. He discovered that he could lay down a rubber strip for as long as he wanted. Up to a 1/4 mile or more. The local police went nuts trying to figure out who was driving so dangerously and speeding so fast, with a car with so much power that it could leave a 1/4 mile rubber stripe in a road. He never went any faster than required. If he went too fast, the spinning would stop. He would put a brand new tire on the car on a Friday afternoon, and by Sunday afternoon, the cords were showing. He always carried a spare. Because he was one of those guys that a lot of his peers wanted to be seen riding in his car, he was never without someone to change the tire. Even if it was raining. If you were appointed as the tire changer, you changed the tire. Or you didn't ride again.

He told me that he sometimes blew through a tire in less than 50 miles. He never collected on a warranty replacement.

Back in the Good-L Days. Yout's havin' Fun in a small town.

ChrisJ

Hmm

Ice,



I'm sorry if I'm a bit slow but I'm not understanding the analogy?

Are saying not following the manufacturer's instructions would only void the warranty of the appliance?

HDE_2

Why is it always missunderstood?

Every time I hear someone say or quote that PVC is 140 degrees, the part they leave out is its a fluid with pressure rating. So let's just finally put that one to bed and stop that misinformation.



If your familiar with ULC-S636, basically they took PVC pipe and fittings and certified it to 149 degrees. This then is certified as type BH class II A rated to 149 degrees. This pipe is just our regular PVC Sch 40 DWV. Then you have the class II B which is CPVC.



I ask you gentlemen, would you be willing to pay 5x the cost for PVC sch 40 pipe, fittings, cleaner and cement to have this "certification" for appliance venting?



Here is a viessmann letter contradicting the recent editorial I referenced earlier stating PVC has a 149 degree rating and top limit of 158. There you have it letter is old but it's written true and correct.



http://www.rural-energy.net/docs/viessmann_Venting.pdf



My purpose here is not to state to everyone that PVC is the vent material for all applications. My point is the uninformed industry wishes to paint with a broad brush that PVC is dangerous as a vent material. And it's not, it has its uses with furnaces, water heaters, boilers and tankless water heaters if applied properly and instructions are followed. Here what I'm saying here? PVC in certain applications carries CSA B149.1 and B149.9 for water heaters and boilers as a venting system with specific manufacturers on specific equipment.



It's our job to read, understand and apply those specific installation instructions and perameters for a proper and safe install.



Let's not keep quoting the one death by PVC that occurred because of lack of proper joints, support and bad install practices.



One more thing for the naysayers, show me certification on 26g steel smoke pipe please? How many have died due to rusted, sagging, plugged venting and vent connectors and has that vent material ever been banned?

HDE_2

Chris

I believe that's the temp it goes soft, not a liquid melt temp

RobG

PVC

The way I see it is that for a long time we all used PVC for venting and it was the greatest thing since sliced bread (if installed properly). Since then, new materials that are approved for venting have come into the mix and we should move on to these materials until the PVC manufactures get their product approved. In these litigious days there is no room for skimping on venting. I still find it hard to believe that heating equipment manufacturers still approve PVC in their manuals.



JMHO,

Rob

icesailor

Using PVC:

I've used tons of PVC.



Does Charlotte say in writing that they approve of their pipe and fittings to be used in venting gas equipment that can possibly go above 140 degrees?



That's all I am saying. If the PVC has a failure because of some reason, will Veissmann  CMA if Charlotte won't?

If I was still doing it, I'd be using Centro Therm PP. Most PVC is improperly installed anyway. No cleaner etc.

RobG

Wow

Ice, you must have been typing at the same time as me!

Steamhead

Not misunderstood

Your quote: "PVC in certain applications carries CSA B149.1 and B149.9 for water heaters and boilers as a venting system with specific manufacturers on specific equipment"



You mean specific appliance/equipment manufacturers, right?



The equipment manufacturers can promote PVC all they want, but as long as the pipe itself is not listed for venting combustion products, it does not meet Code. There are apparently quite a few inspectors who will pass PVC venting, but from what we've seen they always get a pass if there is a lawsuit.



Again, the people who make PVC/CPVC/ABS pipe have not listed it for venting combustion products. And, given the liability involved, they never will. They can sell a lot of pipe while others incur the liability if something goes wrong, so why change things? So the industry has to get away from using this type of pipe for venting.



This reminds me of the debate over using Teflon tape on gas pipe joints. Like PVC/CPVC/ABS venting, it might work fine. But if Code in your area prohibits it, the inspector is within his/her rights to fail the job, and if it goes to court the lawyers will grind you to bits for using a non-approved material.



Remember, our Codes are mostly written in the blood of those who died from the unsafe conditions that prompted writing the Code in the first place. Sure, it's a PITA at times, and some inspectors do their best to make things difficult for contractors, but I'd rather have the Code and the enforcement that goes with it, to protect our industry's good name.

ChrisJ

Actually

This is in Charlotte's PDF for pipe and fittings.



Page 116

http://www.charlottepipe.com/Documents/PL_Tech_Man/Charlotte_Plastics_Tech_Manual.pdf



And as per code 503.4.1.1 Plastic vent joints. Plastic pipe and fittings used to vent appliances shall be installed in accordance with the appliance manufacturer's installation instructions. Where a primer is required, it shall be of a contrasting color.

icesailor

PVC Fittings:

What you posted covers PVC fittings. Maybe it covers pipe too. I haven't read the cited Code reference. However, if there is an overheat situation, and the combustion exhaust is yellow, tan or brown, and the incident is pointing to a vent failure, trust me. Charlotte has paid a lot of money to CTA. PP venting is rated higher. Its cheap insurance. And a lot easier to properly connect.



See that part about properly cleaning the pipes and fittings? 90-% of PVC joint connections I have seen are not properly done. That alone will screw your pooch. Most do not use solvent cleaner and most that do, don't use it properly. Then, there's the unseen issue of chamfering the end of the pipe so as to squeegee the cement out of the fitting.

Technically, from a good practice point of view, you shouldn't use Sch. 40 DWV fittings but Sch.  40 pressure fittings. But you should be using Long Sweep ells or two 45's to try to keep restricted flow down. A Street 45 and a regular 45 equal a long sweep.  Some spies got a giggle when they saw that.

There's no such thing as wrong, just varying degrees of right.

Some things are more right than other things.

ChrisJ

Charolette

The Charlotte PDF was for all of their products as far as I can tell. The code says plastic pipe and fittings so that covers both as well.





My concern is it sounds like all of this falls back on the appliance manufacturer and if you use something they did not tell you to, aren't you now in the wrong legally?

Bob Bona_4

its amusing

To hear about how badly pvc can be installed when its par for course seeing rotted, improperly pitched galvy smokepipe cobbed together with no screws etc etc. The easier it is to install a product is often the easiest to abuse that products intentions.

Zman

Again

It is really just a matter of time on this one. The pipe manufactures have not designed or priced their product for the additional risk associated with gas appliance venting.



I really like Carol Fey who wrote the article and whether you agree with her or not, she makes a very good point.

She does, by the way work for Viessman who has taken a fairly hard stand against PVC venting.http://www.rural-energy.net/docs/viessmann_Venting.pdf

Carl

HDE_2

Please explain further

"The equipment manufacturers can promote PVC all they want, but as long as the pipe itself is not listed for venting combustion products, it does not meet Code"



What national code do you refer to here that excludes PVC to be used as a low temp appliance vent material? I have never heard or seen one.



A local jurisdiction may have one but to state that there is a code preventing the use of PVC is the perpetuation of misformation I have been remarking about.

HDE_2

Exactly Chris

Persons keep spouting off about codes but there are really none as pertaining to PVC venting.



It all falls on the manufacturer, their recommendations and requirements. CSA tested the safety as a system so why does everyone have such a problem? Stop looking past the appliance and at the vent worried about its sole certification or not. Use the material the manufacturer allows and recommends under the specific application and install it right and why worry about the vent?

HDE_2

To reiterate

I posted that link earlier in thread to dispel myth PVC is rated for 140 degrees. Even viessmann admits it is 149 degrees.



So at least we can move on about that?



And of course she takes a stand, there is a financial motive

Bob Harper

talked to death

This has been talked to death but won't go away. The code puts the onus back on the appliance mfr. because GAMA pressured the ICC not to forbid unlisted venting systems. So, they used vague language and left a mess for us to deal with. Positive vent pressure venting should be listed. That means UL 1738 in the US. There are PP systems that are so listed but no PVC. The PP systems do not use cemented joints but rather sliding joints. The material is much higher temp. rated, not as brittle, handles hoop stress better and does not suffer the installation quirks Icesailor discussed about PVC. PVC has no room for error such as even slight overfire conditions or such as discussed in the Viessman's document during the listing process. Venting is not just about passing under bare minimum conditions but under harsh conditions, too. Solid fuel venting usually sees stack temps. around 600-850F but must endure repeated 2,100F chimney fire conditions without the enclosure surface temps. rising more than 90F above ambient. How many overfires above ~159F can a cemented PVC joint take? We declined the polymeric venting listing for PVC in the UL 103 Standards Technical Panel because we saw too many issues. So, if something bad happens, there is a transfer of liability from the PVC mfr. to the appliance mfr. and installer. Ex: you make a potato gun out of PVC and it blows up causing a serious injury. Who do you think carries the liability if it fails? The guy at the paintball park or the mfr. of the gun? Meanwhile, someone got hurt and someone's life is going to be hell during the litigation. PVC is NOT tested or listed as a combustion vent. Mfrs specifically state do NOT use positive air pressure to test it. Mfrs. state don't use it for combustion venting. I spoke with Fernco, who supplies those adapters on B/W power power vented WHs. They sell them with a disclaimer not to use them for combustion venting knowing that's what they are used for. If one fails, its on B/W--not Fernco. Use venting systems listed to UL1738---PP or AL29-4C ss.

Steamhead

"GAMA pressured the ICC not to forbid unlisted venting systems"

Still, when it goes to court, the contractor loses.



We don't use PVC/CPVC/ABS for venting. Ever. If the next guy does, so be it. He's liable, not us.

j a_2

Some manufactures

Some manufactures supply P V C fittings as well as some provide P V C primer and glue…I agree its worth discussing…I have seen some P V C slightly yellowed, but have also seen 24 gage smoke pipe with issues….My opinion is to read the installation manual and follow it…Most manufactures offer specific training on there products…

jonny88

pvc

I just use centrotherm.Easy to use and I know i have no issues.Not getting into the pvc right or wrong thing.

icesailor

Yellow to Brown:

I've seen it light brown, really brown on older Ruud PVP LP water heaters. Not so on the new ones with the different blower and restriction plate at the top.

Paul48

Sashimi

People eat sashimi made from pufferfish , all the time. MOST, don't die. Are you comforted by that fact? The emperor of Japan is forbidden from eating it. I'll pass.

ChrisJ

Huh

I think that's a pretty poor comparison.



Most people don't die in car accidents, yet many do. I still drive a car.





Does anyone have access to statistics that show how many power vent and direct vent systems have been installed with PVC and how many failures there have been?

HDE_2

UL-1738?

UL-1738 excerpt:



"This category covers special gas vents intended for venting certified Category II, III or IV gas-burning appliances as defined by ANSI Z223.1/NFPA 54, "National Fuel Gas Code."

The specific appliance categories that each special gas vent may be used with are indicated in the individual certifications and on the product.

These vents are intended to be installed in accordance with the installation instructions provided with the product. Minimum air-space clearance to combustible materials should be maintained as marked on the vent sections using the parts specified in the installation instructions."



So how does UL-1738 factor in?



Once again back to the manufacturer responsibility and its CSA safety approval as a system appliance and vent.

Paul48

No

The comparison is , dead-on. You see, yours is flawed, in that you are forcing the homeowners to drive the car 24 hours a day, 7 days a week. Ask for an auto insurance quote, under those guidelines.

ChrisJ

Fine

Some people die from eating peanuts.

I eat peanuts.

Paul48

There's Another!

What would you consider acceptable losses? "Mr. Smith, were you aware that there were safer alternatives to using pvc for venting,asked the lawyer?" Please confine your answers to yes, or no. See how this works?

HDE_2

But

Ah yes, people can also purchase and drive safer cars and choose not too.

That car that crushes like an accordion still passes inspection and gets them from point A to B.