Chimney "Continuous Operating Temp" Questions ( or, UL 103HT standard vs. ULC S629 standard)

[turbocruiser]

Wow my head is spinning! I have been trying to figure out the differences and the similarities between different Class A Chimney systems.

The typically specified system offered through my dealer is MetalFab and everything I've ever read really seems super good. It is rated as UL 103HT with an advertised "Continuous Operating Temperature" of 1000F.

But, I've also read thread after thread and THINK (trying to emphasize my extreme doubt in this newly known knowledge of mine!) average temperatures in these Class A Chimneys are around 600 to 750 degrees F (actual inside temps not temps from some surface thermometer). I've also read and THINK (same emphasis on overall doubt) highish temperatures in these chimneys are 800 to 1000 degrees F. Seems that some folks purposely push to 1000F when they are trying to "clean the creosote out".

If this is all halfway accurate I'd like to ask about the benefits (if any) of opting for a chimney system (such as Excell's) where they advertise "Continuous Operating Temperature" of 1200F and they are both UL 103HT as well as ULC S629. How should that factor towards making a product and purchase decision? I also see some specific manufacturers advertise additional tests that they seem to do themselves (such as Simpson's timed tests at various very high temps). How should those tests factor? As I may have mentioned in other threads our dealer is super sharp and although he really likes the line that MetalFab makes he's also agreeable to putting whatever we want (as long as its also listed as acceptable in Regency's info) in there so now's the time to think these things through. With a small sized steel stove like the Regency CS1200 is the 200F degree difference ever even going to matter much? If we ever wanted to put a super large stove in would it matter much then?

Thanks for all the advice; I'm trying to search out most of my own answers here (and I've absolutely learned so much stuff) but sometimes it helps to have another thread as long as I didn't miss one out there already addressing this specific thing? Thanks Again!

 

[gdk84]

All of the listed chimneys are good systems with many happy users. I decided to go with the excel system due to the fact of the highest rating in the U.S. with 30 minute chimney fires versus 10 minutes at 2100F. I do know i will never have the pleasure of testing these claims but I tend to go with the best specs whenever possible.

 

[turbocruiser]

All of the listed chimneys are good systems with many happy users. I decided to go with the excel system due to the fact of the highest rating in the U.S. with 30 minute chimney fires versus 10 minutes at 2100F. I do know i will never have the pleasure of testing these claims but I tend to go with the best specs whenever possible.

Right and if I understood it right in regards to Excel, the "continuous" temp is advertised at 1200F vs 1000F for the MetalFab. On the other hand while the Excel chimney with 6" ID is only 7" OD and requires 2" of clearance to combustibles, the MetalFab with 6" ID is actually 9" OD but has a 1.5" CTC (apparently the closest in the industry?). So within these standardized rating systems there seems to be standardized specs and then also extra tests each company uses to sell their product. I also wonder whether a US company like MetalFab simply opted out of getting the USC ratings whereas Industrial Chimney Co out of Quebec essentially has to have both?

In the end the real questions come down to how hot my stove will make my chimney? It seems that somewhere around 700F would be a big roaring fire for a smaller steel stove like the one that we got but I'm basically guessing on that temp. The other question obviously is how long lasting is the average chimney fire? I mean if the average chimney fire is 1 minute and the UL standard is 3 ten minute chimney fires that might mean more to me. Conversely if the average chimney fire is 2 hours then even the USC standard of 3 thirty minute chimney fires is somewhat sketchy! Arrggh, like I wrote already my head is spinning in information here, it is wonderful and slightly awful at the same time!

 

[pen]

With either of those chimney if you burn well seasoned wood you should never get creosote in that chimney which would be capable of producing a chimney fire. Even if it were, I have not personally seen a properly installed class A chimney fail.

Go with which ever suits your situation the best; make sure you wood has been seasoned at least a year, 2 for species like Oak; inspect / brush that chimney often the first year as you get to learn the nature of the beast; install to code and you'll have no problems.

Also, the "burn it out" thing is something I don't recommend. I recommend burning hot all the time. If you don't need a lot of heat that means a small hot fire. Smoldering is what causes problems. The "hot fire once a day" worked to show you what temperature the creosote you lined your chimney with while having the stove dampened down too far will light off at. If you tried it every day then you may have a small chimney fire often. The idea was a small fire was better than a big one. My point is with good preventative measure you shouldn't ever have to experience one.

pen

 

[Fsappo]

Its hard to go wrong with a class A chimney, if you burn properly, exactly like Pen described. That higher rating on the Excel is impressive though.

 

[turbocruiser]

Its hard to go wrong with a class A chimney, if you burn properly, exactly like Pen described. That higher rating on the Excel is impressive though.

Got It! Thanks for the responses Franks and Pen! Although both systems seem superb, I think I'm going to ask about switching my spec to the Excel for a few reasons.


1. Continuous Operating Temp of 1200F vs. 1000F for most of the other Class A Chimneys I've seen.
2. Tested with 3 Thirty Minute, 2100F fires vs. 3 Ten Minute, 2100F fires.
3. Has both the UL and the USC ratings and I read on several inspection sites that many municipalities are going to go towards a 629/650 chimney code which is what the USC CND/ USC US conversion code is if I understood it right (big IF on my understanding there as always).
4. The 7" OD will be a bit better in my application (although I already would have had 2 inches additional clearance all around the 9" OD MetalFab stuff) but in an enclosed area like a chimney chase any additional clearance is cool.


If for whatever reason its too late to alter the order then we'll put the MetalFab in and probably never think twice about it. As I already mentioned, I cannot find anything negative about it anywhere and it seems a safe, simple, strong product. And, who's to say that if this 629/650 code comes into norm in the future, they might simply take this same product and achieve that rating too without really modifying anything; I'm pretty convinced that there isn't currently much market motivation for them to pursue the USC specific standards.

Anyway as long as it isn't a PITA type of request for a customer to make of a dealer at this point (if it is please somebody say so and I'll avoid even asking) I think I'll ask about switching my spec and if I can't then no worries at all. Thanks again for all the advice I hope I'm not missing these specific questions somewhere else? Thanks.

 

[oconnor]

All of the listed chimneys are good systems with many happy users. I decided to go with the excel system due to the fact of the highest rating in the U.S. with 30 minute chimney fires versus 10 minutes at 2100F. I do know i will never have the pleasure of testing these claims but I tend to go with the best specs whenever possible.

Right and if I understood it right in regards to Excel, the "continuous" temp is advertised at 1200F vs 1000F for the MetalFab. On the other hand while the Excel chimney with 6" ID is only 7" OD and requires 2" of clearance to combustibles, the MetalFab with 6" ID is actually 9" OD but has a 1.5" CTC (apparently the closest in the industry?). So within these standardized rating systems there seems to be standardized specs and then also extra tests each company uses to sell their product. I also wonder whether a US company like MetalFab simply opted out of getting the USC ratings whereas Industrial Chimney Co out of Quebec essentially has to have both?

snip

The ULC spec S629 is a different spec than the UL 103HT. Canada ( hence the ULCS629 spec) requires longer exposure to chimney fire temps than the US does in it's testing regimes, and also requires the higher continuous use temp. Given that Industrial Chimney sells in both markets, they test to both.

As for the CTC differences, the specs (ULCS629 or UL103HT) don't state anything about clearances, they cover what the condition of surrounding combustibles must be after the exposure, when the product is installed according to manufacturer directions. So, if someone came up with a super insulating material that was an inch thick and didn't allow damage to combustibles at zero clearance to combustibles, they would get it tested, and if it passed, you would have a ULCs629 spec product that had a zero clearance instruction.

The reverse could also be true, that someone could build a product using crap insulation and specify 10 inches of clearance, and it would get ULCS629 approval (in theory) when installed at 10 inches from combustibles.

 

[oconnor]

Its hard to go wrong with a class A chimney, if you burn properly, exactly like Pen described. That higher rating on the Excel is impressive though.

Got It! Thanks for the responses Franks and Pen! Although both systems seem superb, I think I'm going to ask about switching my spec to the Excel for a few reasons.


1. Continuous Operating Temp of 1200F vs. 1000F for most of the other Class A Chimneys I've seen.
2. Tested with 3 Thirty Minute, 2100F fires vs. 3 Ten Minute, 2100F fires.
3. Has both the UL and the USC ratings and I read on several inspection sites that many municipalities are going to go towards a 629/650 chimney code which is what the USC CND/ USC US conversion code is if I understood it right (big IF on my understanding there as always).
4. The 7" OD will be a bit better in my application (although I already would have had 2 inches additional clearance all around the 9" OD MetalFab stuff) but in an enclosed area like a chimney chase any additional clearance is cool.


If for whatever reason its too late to alter the order then we'll put the MetalFab in and probably never think twice about it. As I already mentioned, I cannot find anything negative about it anywhere and it seems a safe, simple, strong product. And, who's to say that if this 629/650 code comes into norm in the future, they might simply take this same product and achieve that rating too without really modifying anything; I'm pretty convinced that there isn't currently much market motivation for them to pursue the USC specific standards.

Anyway as long as it isn't a PITA type of request for a customer to make of a dealer at this point (if it is please somebody say so and I'll avoid even asking) I think I'll ask about switching my spec and if I can't then no worries at all. Thanks again for all the advice I hope I'm not missing these specific questions somewhere else? Thanks.

Another point - the two specs mentioned aren't building codes, they are engineering specifications. When it comes to engineered chimney (i.e.prefab) installations, most building codes only specify that the product must be installed according to manufacturers instructions.

 

[turbocruiser]

Right, that was what I was understanding too. I tried to make it clear that ICC and their Excel product advertises such and such clearance and not that the USC S629 specifies any standard clearance. This is the same situation in fact for MetalFab and their TempGuard in the sense that their product is rated as UL 103HT but they advertise the 1.5" clearance. So the specific clearance isn't standardized in either the UL or the USC code. Sorry if my mixing of products and standards made a mess of that.

It is probably pretty different region by region but my Regional Inspector is actually looking at the UL 103HT rating as required componentry currently and they are also already considering the USC S629 rating as required although I think that will be written (conversion code) as "UL S650" with the same testing as USC S629. Anyways my point there is that my inspector is actually looking at that rating as required. The rule though is "current code applies at time of the permit process" so even if they indeed do decide to go to UL S650 (or whatever it will be called) later on, we will be alright as long as we pass the permit inspection presently.

There's no question in my mind that the MetalFab will work and will work wonderfully well, I was just attracted to the higher continuous operating temperature, the longer testing times and the smaller OD of the ICC product.

 

[turbocruiser]

Awesome Update! I spoke to the stove shop owner/operator and he was absolutely wonderful about humoring my request. He promptly provided pricing info on the Excel (which will only be $200 to $250 more than the TempGuard) for the same setup and told me that he would order it and use it for my install! I just can't comment enough on how professional, polite and knowledgeable this stove shop is. I'm sure that the TempGuard would have worked as well as the Excel but again for a few other reasons it will be better with my particular place to have the Excel in there. Thanks again for all the advice folks, I really appreciate it all.

 

[jimbom]

....

In the end the real questions come down to how hot my stove will make my chimney? It seems that somewhere around 700F would be a big roaring fire for a smaller steel stove like the one that we got but I'm basically guessing on that temp.

Great topic and your thought process is excellent.

The building is built for the extreme wind, the levee for the extreme flood, the armor plate for the greatest threat, etc. Likewise, the stove and chimney installation should always be thought of in terms of the chimney fire. You will not be responsible for the fire, but someday you may sell and move. The new family may not know how to maintain a chimney and will have a dangerous fire. So, we create a safe installation for all the families to follow.

Always design and build for the worst case and your mind will be at rest. It this case, you have done just that.

 

[FyreBug]

Another point on Chimney temps is while an EPA stove might use the same chimney brand as an inefficient one or ZC fireplace; the temp differential between these will be huge.

A large inefficient ZC could see spikes in temp as those you mentioned in your post, while an EPA one will pretty much remain steady in the 350 to 600 range.

 

[turbocruiser]

Another point on Chimney temps is while an EPA stove might use the same chimney brand as an inefficient one or ZC fireplace; the temp differential between these will be huge.

A large inefficient ZC could see spikes in temp as those you mentioned in your post, while an EPA one will pretty much remain steady in the 350 to 600 range.

Hmm, that is very interesting ... I would not have thought of that. Another thing I just found out from ICC is that among all the tests that they advertise for the UL and the USC ratings, they also test for a full 8 hours at 1200 F I thought that was pretty interesting info too; can you imagine how red hot the stove would be when baking the chimney at 1200F for a full 8 hours. Yikes! Anyways again thanks for this post I really wouldn't not have thought of that.

 

[FyreBug]

glad to oblige...