NFPA

[warbonnet]

Can someone point me to the scientific test and results that NFPA conducts on uninsulated chimney flues. I am a member of NFPA and get daily emails as well as snail mail ,but must have missed the part about chimney flue scientific testing.

 

[BrotherBart]

As far as I know, NFPA hasn't ever tested anything. They rely on UL test results.

 

[warbonnet]

Ok, so can someone post the source of these test? Mention of these test and codes are posted a great deal here. I think it would be beneficial to the membership in general to have the ability to see this testing info at its source first hand. I would like know what kind of controlled enviroment these test were conducted under. It would clear up any muddy waters. A link to where the experts obtain this info would be great.
Thanks in advance.

 

[begreen]

The National Bureau of Standards is referenced for chimney liner testing
http://www.csia.org/homeowner-resources/about_chimney_liners.aspx
http://fire.nist.gov/bfrlpubs/fire87/PDF/f87007.pdf

Perhaps also helpful, here is the reference book for UL Standard103
http://ulstandards.ul.com/standard/?id=103
NFPA Masonry Chimney standards
http://www2.iccsafe.org/states/seattle/seattle_residential/PDFs_residential/Chapter 10.pdf

 

[BrotherBart]

The NFPA and UL code books have to be purchased. Your local fire department and building inspector's office should have copies. Most localities adopt parts of the codes as they feel appropriate.

Some access to NFPA codes and standards are available here. Wanna why they are what they are? Ask NFPA.

http://www.nfpa.org/codes-and-standards/free-access

Some access to UL standards are available here. Wanna why they are what they are? Ask UL.

http://ulstandards.ul.com/access-standards

 

[warbonnet]

I have up to date NFPA books. I administer required testing on commercial sprinkler systems and fire alarm systems. I am looking specifically for the testing data where a liner inside terracotta inside concrete block was able to ignite wood placed against the block. I know this is repeatedly posted to be a code violation. I would like to see the test data. I find it hard to believe this information is not right at hand of those posting these things? Again just trying to get a clear understanding the circumstance that would cause such an inprobable thing to happen. I would think its near impossible.

Thanks again.

 

[begreen]

Contact CSIA, they report this testing was done by the National Bureau of Standards. (links provided above) Or wait for bholler to respond. He is the chimney safety expert.
"In the NBS tests, unlined chimneys allowed heat to move through the chimney so rapidly that the adjacent woodwork caught fire in only 3 1/2 hours."

Again just trying to get a clear understanding the circumstance that would cause such an inprobable thing to happen. I would think its near impossible.

Link to source thread please

 

[elmoleaf]

Quick google search found this: Thermal Performance of Masonry Chimneys and Fireplaces.
http://fire.nist.gov/bfrlpubs/fire87/PDF/f87007.pdf
Has quite a bit of info, and I'm sure there plenty more online. Also try googling "pyrolysis" and "chimney" together.

 

[jatoxico]

Quick google search found this: Thermal Performance of Masonry Chimneys and Fireplaces.
http://fire.nist.gov/bfrlpubs/fire87/PDF/f87007.pdf
Has quite a bit of info, and I'm sure there plenty more online. Also try googling "pyrolysis" and "chimney" together.

I believe that is the same one @begreen linked and has a lot of good info.

I am looking specifically for the testing data where a liner inside terracotta inside concrete block was able to ignite wood placed against the block.

I started reading the link above and though it could be clearer in the body of the report, according to the diagram on pg 34-35 the steel liner tests were conducted with the liner installed in a flue already lined w/ clay tile. Someone please correct me if I got it wrong, I'm skimming on XMas morning!

I think this is a good thread and topic.

 

[brenndatomu]

Or wait for bholler to respond. He is the chimney safety expert.

Give ole @bholler a holler...

 

[jatoxico]

The study linked (87-3515 pdf) has plenty of good info but is rather poorly written in many respects. Most stuff is nuisance but some info could/should be much clearer. So this is some of what I got from reading.

Section 4 on pg 17-18 states the relining techniques used were designed to "compare" different lining systems to clay yet the figures provided on pgs 34-35 indicate the steel was additional so no real comparison there. In Fig #1 (stove setup) they say steel liner was placed inside the clay and the poured masonry liner replaced the clay. No similar info is given for Fig #2 (insert testing). Guess reader assumes it was the same (?). In the end after reading I'm pretty sure that all tests with steel liners were done by inserting into clay tile but not 1000% sure.

In any case if I read it right when testing inserts with stainless liners they did record maximum temps higher than the recommended constant heat maximum for a combustible on the outside brick of the chimney. According to the article the max constant recommended temp is between 65-100 C (pg 14 Para #1) depending on reference source and they recorded 120 C with the large insert and full steel liner to the top.

They did not ignite any wood. Tests were not conducted for days and months on end and the chimneys were constructed in observation of all applicable clearances including an air space between the outer brick and wood. But, theoretically any combustible in contact with that (outer brick) surface could, over time be ignited.

Of course a transient maximum temp is not the same as constant heat source so the likelihood of an actual ignition would be highly variable depending on each individual circumstance and history of each setup. Tests were performed in normal and "overfire" conditions but chimney fire, which would be much hotter was not replicated so clearly keep it clean.

Sorry for geeking out.

 

[Smoked]

This one is not chimney related but really got my attention as I have hot water heat too (broken link removed to https://www.doctorfire.com/low_temp_wood1.pdf)
Someone else shared this on another thread a few weeks back but I can't remember which one. 170 F + ~ time = ignition, really scary

 

[begreen]

Pyrolysis is serious business. It's like hidden a time bomb in the structure of the house. No one can say how long it will take before ignition will happen. It's better to invest a little up front on the side of caution and safety than to wait for later results.

 

[jatoxico]

Pyrolysis is serious business. It's like hidden a time bomb in the structure of the house. No one can say how long it will take before ignition will happen. It's better to invest a little up front on the side of caution and safety than to wait for later results.

No doubt but still a worthwhile topic for discussion IMO. When attempting to apply the data collected in the linked study to any given install it would be critical to know at what height and for how long temps above the maximum recommended temp were present on the outer brick surface of the chimney. With that you might make some educated guesses regarding the real world potential for pyrolysis when assessing an individual install assuming improper clearances (i.e. combustible in contact) since that cannot easily be assessed once the walls are closed up.

Presumably the hottest points measured in the chimney would occur at the lowest measured points, which according to the diagram would be below ceiling height. For instance in my case I'd like to know what temps were recorded on the outer brick when the inserts were fired with a clay and steel liners at the closet point measured near around 2.5 m since that's the first place I have the possibility of framing contacting the outer brick of my chimney. Unfortunately only max temps recorded were given and even the raw data is indecipherable to me so far.

Of course its impossible to make blanket statements on the web considering that the condition of the existing flue and observation of clearances in any given install is unknown.

 

[2broke2ride]

I would like to know why, if this has been code for so long, are there so many chimneys in so many houses done blatantly wrong yet they where all inspected and signed off on when built...... We obviously are a somewhat educated lot here, imagine just being joe homeowner and having no idea that your house could go up in flames at any minute....... I know people around here, even people I know in the chimney business, have never even heard of clearance to combustibles for a masonry chimney and find the notion absolutely ridiculous. It is obvious that this doesn't make it right, just wondering why it's so unknown.

 

[jatoxico]

I would like to know why, if this has been code for so long, are there so many chimneys in so many houses done blatantly wrong yet they where all inspected and signed off on when built......

Nature of the beast I suppose. The same could be said for a lot of dangerously done, not to code construction work that is covered by existing building codes. Tons of poorly trained workers and inspectors out there, not to mention homeowner remodeling. A lot of people complain about gov't building codes but I always figured they were useful in making sure contractors were held to some minimum standard.

 

[begreen]

If the house is built from scratch and if the contractor built to code and if the mason did the chimney and liner properly then a text book example should give somewhat predictable results. Problem is people often take shortcuts or have the helper do some of the work or a subsequent remodel ignores code clearances. The only way I knew what wood was touching our chimneys was when I tore them out. What I saw definitely scared me. In one location there was wood right over a covered up take-off thimble. The other thing that is hard to predict is the actual wood used during construction and construction method. The smaller or thinner the piece of wood the faster it will pyrolyze. Think plaster lath here or a pipe going through a splintery hole.

 

[BrotherBart]

Heck when I had the inspector out to sign off on my install of the liner and stove into my masonry chimney for the basement I had to give the inspector a free course on SS liners. He had never seen one installed before.

 

[BrotherBart]

More reading on chimney inspecting than anybody will ever read:

http://inspectapedia.com/chimneys/Masonry_Chimney_Fire_Clearances.php

 

[2broke2ride]

Nature of the beast I suppose. The same could be said for a lot of dangerously done, not to code construction work that is covered by existing building codes. Tons of poorly trained workers and inspectors out there, not to mention homeowner remodeling. A lot of people complain about gov't building codes but I always figured they were useful in making sure contractors were held to some minimum standard.

I can believe this to some extent but I have heard it said here before that something like 95% of masonry chimneys have inadequate clearances. Surely that number is a bit high to be "slipping through the cracks". I know my chimneys do not have the clearance and never have, the house is as built in the early 50s. I also have a friend with a house built in the 80's, I helped him do new siding and his chimney has no clearance either and he told me I was insane when I said there should be clearance. It just seems crazy that this problem is so rampant yet it seems nobody knows or cares outside of these forums.

 

[jatoxico]

I know my chimneys do not have the clearance and never have

Mine either. I can see brick in my attic through an old electric box hole in the siding. Must have been for an outside light that was covered over when they put the chimney in. The brick is right up on the siding. I have shot it with an IR thermometer and its cold but I have no doubt the entire chimney above the first floor ceiling is in direct contact with the tar paper covering the tongue and groove siding.

 

[bholler]

Ok guys i have said it many times there is nothing saying that without insulation you will burn your house down. And i have never seen a fire caused by an uninsulated liner in a masonry chimney with inadequate clearances other than one where the chimney was not cleaned first and the old creosote caught between the old and new liners. But i have seen them in clay lined chimneys with inadequate clearances and due to the fact that that stainless does nothing to stop heat transfer i dont see much difference. I do not know of any links to the testing procedures but i have personally seen a ul test being done on a liner system and the one without insulation was absolutly hot enough to ignite pyrolised wood. And no i cant go into much detail due to nondisclosure agreements that i had to sign before being allowed in the facility.

 

[bholler]

But like others have posted there is allot of info available on the web about this if you search. And the fact is that it is required by code and the ul listing so that in and of itself should be enough to spend the little extra and do it right