NFPA's 18" Hearth Requirement

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It seems the new NFPA requirement for 18" of floor protection in front of wood stove loading doors might actually have zero impact on most installations. Any manufacturer who submits a given stove for testing can get tested for a shorter hearth, and, if the stove passes, list that shorter hearth requirement in the installation manual. At that point, the tested listing would supercede the NFPA's standard requirement.

Example: NFPA 211 calls for 36" stove clearance to a combustible backwall, reduceable with proper wall shielding. A manufacturer can include rear shielding on a given stove model, submit it for testing, and achieve a listing much closer than this (we carry wood stove models that can be installed as close as 4" to an unshielded combustible backwall). In cases where a stove is listed for closer clearances than the standard clearance specified by NFPA 211, the listing takes precedence.

Example 2, more to the point: NFPA has required 16" clearance in front of a wood stove loading door for many years, and that's the standard most manufacturers test to. Most, but not all: Pacific Energy tested their Pacific D1 wood insert with a 2" raised hearth that extended just 10-5/8" in front of the loading door (a total of 16" measured from the fireplace facia). The D1 passed the test, and achieved a listing for installation with the shorter hearth. Even in Canada, which has long had an 18" standard hearth extension requirement.

Example 3, bringing it current: Hearthstone's new Equinox wood stove is still in the lab, undergoing clearance testing. The floor protection test has been completed, however, and the Equinox got a 16" hearth extension listing. This ocurred after the NFPA's switch to the 18" standard hearth requirement.

I've checked with the code inspectors in all five code jurisdictions our installers work in, and all are in agreement: they will continue to measure the hearth according to the manufacturer's listing as it appears in the installation manual.

The bottom line, as I see it: if you're installing a homemade wood stove, it had better be at least 36" from an unshielded backwall, and have floor protection extending at least 18" in front of the loading door. If you're installing a UL listed wood stove, the clearances and floor protection requirements listed in the installation manual will pass inspection.
 

jtp10181

Minister of Fire
Feb 26, 2007
3,734
Madison, WI
That's the stance we were taking as well. Makes sense to me.
 
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elkimmeg

Guest
I looked far and wide used search functions but could not come up with code language the applies to codes being trumped But I did come up with language stating codes take presidence
The other factor is there is no language where I have to approve manufactures specs if I can hang my hat on code language Naturally a greater percentage of times manufactures specs will be adhered to In this case the actual listing contradicts its self Most stoves list being compliant to NFPA 211 or teste to NFPA 211 They already call in NFPA 211 into the inspection process.
Again If I adhere to NFPA 211 which is called in as a recognized code and Apply 18" I have grounds to do so My signature can't be trumped, unless you have a state inspector over rule me.

Here is the code language giving me my authority (when I am saying me here I mean all inspectors)

SECTION R102*

*APPLICABILITY*

*R102.1 General. *Where, in any specific case, different sections

of this code specify different materials, methods of construction

or other requirements, the most restrictive shall

govern.

*R102.4 Referenced codes and standards. *The codes and

standards referenced in this code shall be considered part of the

requirements of this code to the prescribed extent of each such

reference. Where differences occur between provisions of this

code and referenced codes and standards, the provisions of this

code shall apply.

*Exception: *Where enforcement of a code provision would

violate the conditions of the listing of the equipment or

appliance, the conditions of the listing and manufacturer’s

instructions shall apply.
 

Gooserider

Mod Emeritus
Nov 20, 2006
6,737
Northeastern MA (near Lowell)
elkimmeg said:
I looked far and wide used search functions but could not come up with code language the applies to codes being trumped But I did come up with language stating codes take presidence
The other factor is there is no language where I have to approve manufactures specs if I can hang my hat on code language Naturally a greater percentage of times manufactures specs will be adhered to In this case the actual listing contradicts its self Most stoves list being compliant to NFPA 211 or teste to NFPA 211 They already call in NFPA 211 into the inspection process.
Again If I adhere to NFPA 211 which is called in as a recognized code and Apply 18" I have grounds to do so My signature can't be trumped, unless you have a state inspector over rule me.

Here is the code language giving me my authority (when I am saying me here I mean all inspectors)

SECTION R102*

*APPLICABILITY*

*R102.1 General. *Where, in any specific case, different sections

of this code specify different materials, methods of construction

or other requirements, the most restrictive shall

govern.

*R102.4 Referenced codes and standards. *The codes and

standards referenced in this code shall be considered part of the

requirements of this code to the prescribed extent of each such

reference. Where differences occur between provisions of this

code and referenced codes and standards, the provisions of this

code shall apply.

*Exception: *Where enforcement of a code provision would

violate the conditions of the listing of the equipment or

appliance, the conditions of the listing and manufacturer’s

instructions shall apply.
I understand where you are coming from on wanting to stick with code Elk. To me the question occurs that NFPA calls for that 36" clearance to the rear wall, but as Tom has pointed out, many stoves are listed by their manufacturers as having a lot less of a requirement.

As I understand what you've said in the past, if the stove maker says you only have to have 2" of clearance, you only make them use 2". Yet here you seem to be saying that you won't accept a reduction in the 18" number for the front extension because in your opinion NFPA trumps the manufacturer. By that logic you should be insisting on the 36" number for rear clearance, so it looks like you are using a bit of a double standard.

I'm not trying to argue the point, but I'd like to understand why you accept the MFGR numbers in one case, but not the other - what is the difference? Does the NFPA rear clearance language say something to the effect of "36" or the stove manual, which ever is less"?

Gooserider
 

DriftWood

Minister of Fire
Apr 5, 2006
718
Bluewater Area, Great Lakes
Is 18 inches enough?
My stove called for 16 inches of Hearth from the front glass door, the inspector wanted to see 18 inches TWO years ago. So I compromised at 20 inches of Hearth From the front door glass . I still have burn marks on the floor at 26 inches and 36 inches from sparks and hot coals falling out.
 

Corie

Minister of Fire
Nov 18, 2005
2,430
Halifax, VA
The manufacturer's numbers that coming from testing trump the default code numbers. We've been told that and that's the stance we are taking. What's the point of doing clearence and floor protection testing if you just default to the NFPA 211 stuff anyway?
 

Gunner

New Member
Sep 20, 2006
851
Southern Ontario
18 inches, I thought it was 18 ft. :lol:

Maybe this is why alot of people tell the town to pound sand and forgo the permit.
 

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cbrodsky

Member
Jan 19, 2006
517
Millbrook, NY
elkimmeg said:
I looked far and wide used search functions but could not come up with code language the applies to codes being trumped But I did come up with language stating codes take presidence
The other factor is there is no language where I have to approve manufactures specs if I can hang my hat on code language Naturally a greater percentage of times manufactures specs will be adhered to In this case the actual listing contradicts its self Most stoves list being compliant to NFPA 211 or teste to NFPA 211 They already call in NFPA 211 into the inspection process.
Again If I adhere to NFPA 211 which is called in as a recognized code and Apply 18" I have grounds to do so My signature can't be trumped, unless you have a state inspector over rule me.

Here is the code language giving me my authority (when I am saying me here I mean all inspectors)
Elk, I'm sorry, but this attitude is exactly why many intelligent people do not ever get work inspected. Your position absolutely defies all scientific logic after manufacturers spend tens of thousands of dollars testing these stoves in certified labs to come up with appropriate recommendations.

Unfortunately, nobody knows what kind of inspector they will get in their township, so many don't take the risk. Yes, I said risk... because it is a tremendous financial risk to have an inspector make bad decisions while talking about how powerful they are and nobody can do anything about what they declare, etc... resulting in people tearing up perfectly good/safe work because someone is on a power trip.

As a result, you won't see a huge percentage of the work that homeowners perform. This kind of attitude just further encourages people to avoid permitting whenever possible, and you had better believe that is a lot. A more constructive approach would be to say "hey, yea, this is really silly and doesn't pass the common sense test - as code professionals, we should probably make sure this gets clarified ASAP so no crazy inspector tries to apply such absurd reasoning over a manufacturer's thorough testing."

-Colin
 
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elkimmeg

Guest
Naturally a greater percentage of times manufactures specs will be adhered to
That is a direct quote I made when discussing this issue. To me it is an honest statement and not a power trip.

Did you know there is also an appeal process, should you not like the decision of your local inspector? Again one has to have a certain Basis for applying for an appeal.
There has to be a valid discrepancy that can be documented. Same goes to the code official he can't make it up. He has to have code. manufacturer's listing documentation ,
to support his decision.

This issue is a safety issue that the decision is made. This is not bringing forward some outdated code and applying it. A lot of recent research went into the amendment. 90% of most inspections, the current inspector has not read the most recent code and will be accepting 16" Unfortunately NFPA has not posted a commentary giving background info and reasoning for the amendment yet. If I had it I would post it. You may want to jump on the band wagon here to pile it on. This forum is educational to me as well. When wrong I will admit it and move forward learning from past mis information.

Unlike the poster here If I make a mistake I can get sued. I'd rather error on the side of safety every time when it comes to life safety issues. You only have to live with your decisions or compromises. I think it unfair to ask me to do so for you, then if something happens, come after me and sue me

Again please insert inspector in place of me. IT's not meant to be that personal. Which I think a few people missed
 

webbie

Seasoned Moderator
Nov 17, 2005
12,184
Western Mass.
As stated long ago, (Jay Shelton), there is no measurement.....16". 20", 18" or even 24" which will avoid sparks.

I also would say that testing and listing trumps NFPA....NFPA is mostly for stuff that is not addressed in the manual/listing or "generic" situations in this case.

That said, I think it is a "he said, she said" - Chances are that stove manufacturers tested and passed to 16" BECAUSE they took their cue from NFPA. That is a guess.....but an educated one. Otherwise, they could have probably passed at 15" or 14".

If I were an inspector (and I am not), I would probably use discretion for a couple years....existing hearths, for instance, should not have to be extended. But taking some other situations:
1. I would use the NFPA for all masonry fireplaces right away
2. There is no reason not to tell homeowners and contractors to do this with stoves right away....even if the manual says otherwise.

Where the discretion comes in is when an inspector has to inspect a job that is already done, and other such stuff.....happens a lot. If the install matches the manual and listing, I would think it was OK......

As far as appeals....yes, anyone can do this. I did it once and won. I think a customer with backup from literature, a brochure and a fax from the manufacturer would probably win also. Of course, it is a PITA making an appeal.

If this was a serious safety issue, the testing labs would inform the manufacturers to change their manuals and place new labels on- and send a note to dealers and customers. But it is not a serious safety issue....it is one of thousands of normal changes in code which are made every cycle. That means compliance also comes into effect in the normal way.....slowly, but surely.

I will agree with BOTH sides. Testing "trumps" NFPA, but my guess is that the labs (UL, Omni, etc.) will update their own minimum standards to reflect NFPA in the future. As far as enforcement, that is up to Elk. It is like when a new law gets passed - a police officer has the right to enforce it....or, they can warn the person saying "hey, this new law was passed, and therefore make certain you wear your seat belt next time".

Bottom line - simple changes like this should not (in my opinion) cause either inspectors, manufacturers or customers to fret....and it would (again, IMHO) be overkill for anyone to have to reconstruct or rip out hearths made in accordance with the listing and label on the stove.
 

backpack09

Minister of Fire
Sep 10, 2007
554
Rochester, Mass
I recommend a test out of your stove.... Roll a log out of the front of it and see how far it goes...

I will be installing atleast an 18" pad infront of my stove. The manufacturer recommends 16" NFPA says 18". I don't want to have to cut tiles, so it will be around 19 or so... depending on where the stove ends up... I am doing it myself, so my measurements always end up a bit off.

But in the end, will an extra 2" of hearth infront of your stove cost you all too much in the end? That is only 1 extra brick or half a 4x4 tile.
 

webbie

Seasoned Moderator
Nov 17, 2005
12,184
Western Mass.
Ha Ha...... even those presto logs have one flat side so they don't roll out of the fireplace!

You are right - 2" extra isn't anything.....and for open fireplaces this is good practice anyway. I think the point is that we should not think that either existing hearths nor stoves installed by the "book" (manual) are "illegal" or anything like that. It is simply a matter of there being an update in the "agreement" (code), that is preferred. Once it is in the manual and on the label, it is clear that it is a MUST as opposed to a "might".
 

Gooserider

Mod Emeritus
Nov 20, 2006
6,737
Northeastern MA (near Lowell)
Webmaster said:
Ha Ha...... even those presto logs have one flat side so they don't roll out of the fireplace!

You are right - 2" extra isn't anything.....and for open fireplaces this is good practice anyway. I think the point is that we should not think that either existing hearths nor stoves installed by the "book" (manual) are "illegal" or anything like that. It is simply a matter of there being an update in the "agreement" (code), that is preferred. Once it is in the manual and on the label, it is clear that it is a MUST as opposed to a "might".
Well I've got lots of rounds that were NOT "manufactured" w/ a flat side, and which would roll quite nicely if given the chance. :bug:

I think we all agree that an existing by the book install is not made illegal by this change, though the question does arise about replacing an existing stove - If I swap out stoves on a legal hearth w/ one that keeps the same front clearance is the new stove "legal"?

More to the point I think is the question of why is it considered OK to ignore the NFPA 36" spec on side and rear clearances if the MFGR says it's OK, but not the NFPA 18" spec w/ the same MFGR OK? I'm not arguing the rule, as I think 18" is better also, but "Enquiring Minds Want to Know Why"

One thing that would make life somewhat easier is if there was more of a "mult-step" protection requirement so that one didn't necessarily have to meet the same R-values in an extension as they did under the main hearth - i.e something like "Under the stove R-2.0; w/in 6" of the stove R- 1.0; balance of distance "non-combustible construction"" An extension isn't to bad if it's just at the "Tile on Durock" level, but can get to be a pain if you start needing serious R-value numbers.

Gooserider
 

ChrisN

Feeling the Heat
Nov 19, 2005
272
Southeastern, Ct
I can understand how a manufacturer could perform tests of heat shields etc to reduce the 36 inch clearance requirement to combustables, but how would one be able to approve a shorter front clearance? Seems to me that the 18 inch distance must have been established after some sort of statistical survey of flying sparks, log roll-outs etc. A stove is a stove, with the front door open how can one manufacturer state that the sparks from their stove won't fly as far as the sparks from another?
 

BrotherBart

Modestorator
Staff member
Gunner said:
18 inches, I thought it was 18 ft. :lol:
With Canadians drinking all of that high octane beer, 18 feet is reasonable clearance in front of the stove.

"Hey hosers. Watch me chuck this split into the Summit from across the room, eh?"
 

cbrodsky

Member
Jan 19, 2006
517
Millbrook, NY
So I have an interesting question... I have about 17" in front of my door - after which I have a lumber framed wall capped with 1" of tile / cement board in place of drywall. (see profile photo)

Clearly a noncombustible surface and nowhere for sparks to fly onto the floor unless they go out 17" with enough force to ricochet laterally. But it's not an 18" hearth extension.

Wonder how that reads under new NFPA rules...

-Colin
 

BrotherBart

Modestorator
Staff member
NY Soapstone said:
So I have an interesting question... I have about 17" in front of my door - after which I have a lumber framed wall capped with 1" of tile / cement board in place of drywall. (see profile photo)

Clearly a noncombustible surface and nowhere for sparks to fly onto the floor unless they go out 17" with enough force to ricochet laterally. But it's not an 18" hearth extension.

Wonder how that reads under new NFPA rules...

-Colin
I don't think the guys that write that stuff ever saw a side loader without front doors in their life.
 

Gooserider

Mod Emeritus
Nov 20, 2006
6,737
Northeastern MA (near Lowell)
chrisN said:
I can understand how a manufacturer could perform tests of heat shields etc to reduce the 36 inch clearance requirement to combustables, but how would one be able to approve a shorter front clearance? Seems to me that the 18 inch distance must have been established after some sort of statistical survey of flying sparks, log roll-outs etc. A stove is a stove, with the front door open how can one manufacturer state that the sparks from their stove won't fly as far as the sparks from another?
Actually my understanding is the front clearance is supposed to be more to deal with the question of heat coming off the front of the stove - w/ only minor consideration of the sparks and such issue. This is why some stoves require high R-value hearth extensions. A lot of heat is radiated through the glass front doors on a stove or insert.

In some ways flying sparks or rolling logs would make things more of a challenge to figure out - Would you need more clearance on stoves with higher doors, or split level hearths since that would allow sparks a longer trajectory, and let rolling logs go further? OTOH, if merely trying to deal with an ignition source rather than heat, the only thing needed would be a non-combustible construction as opposed to some higher R-value.

Gooserider
 

cbrodsky

Member
Jan 19, 2006
517
Millbrook, NY
BrotherBart said:
NY Soapstone said:
So I have an interesting question... I have about 17" in front of my door - after which I have a lumber framed wall capped with 1" of tile / cement board in place of drywall. (see profile photo)

Clearly a noncombustible surface and nowhere for sparks to fly onto the floor unless they go out 17" with enough force to ricochet laterally. But it's not an 18" hearth extension.

Wonder how that reads under new NFPA rules...

-Colin
I don't think the guys that write that stuff ever saw a side loader without front doors in their life.
Which interestingly, was an important issue that got me looking at this stove... rather unusual in that regard. It was the only legal way I could install the stove the way I wanted without a hearth that extended way out into the middle of a floor where it would have looked silly.

Of course I like side loading and only wanted to use side or top loading, so I could have just welded a front door on another stove and it would have been safe for eternity. But who knows whether that would pass for inspection - again, depends on someone's personal weighting of code vs. common sense.

Would be nice if a stove manufacturer could provide an "approved" way of disabling undesired stove doors.

-Colin
 

cbrodsky

Member
Jan 19, 2006
517
Millbrook, NY
Gooserider said:
Actually my understanding is the front clearance is supposed to be more to deal with the question of heat coming off the front of the stove - w/ only minor consideration of the sparks and such issue. This is why some stoves require high R-value hearth extensions. A lot of heat is radiated through the glass front doors on a stove or insert.

Gooserider
Indeed - I think that is the one spec on the Woodstock that I'd view as more borderline than anything else on the install - when running full out, the floor in front of the stove definitely gets rather toasty - much warmer than anywhere underneath the stove where there is a bottom heat shield, or the other three sides of the stove.

But the manufacturer's test says that while I have to have 16" for the loading door, I only need 8" on all other sides, including the front of the stove. I suppose it passed tests like that, so I guess it has to get really darn hot on the floor before it's a problem. Go figure... maybe the NFPA will work on that next year. A case where common sense will probably lead me to put some type of extra floor protection in someday even code says I don't have to.

On a different subject, how many other manufacturers specify the approach of using a sheet metal sandwich to both reflect and help spread heat out over a larger area? This struck me as a good idea that would likely allow for thinner hearths in lots of applications if it could be reliably modeled for NFPA purposes.

-Colin
 

stoveguy2esw

Minister of Fire
according to this article as i read it, NPFA 211 is essentially a guideline for unlisted stove models, or units which the listing is unclear thus following the CYA method of installation. posts in this thread have identified that ; one, nfpa requirement to the opening side of a unit is to be 18 inches, per the article this has always been the case for unlisted units, two, the recommended clearances on the other sides is apparantly accepted as "manual is gospel" that being the case , why is it that the NFPA required clearance of 18 inches clearance on all sides is superceded by the manual. if the manual is correct in these areas then how is it incorrect in the clearance to the opening side? third, by establishing a clearance of 18 inches to the opening side, up from 16 inches, nfpa apparantly has tested and found that logs are capable of rolling at least 1.5 inches further now than they have been in previous years (bringing to my mind the flurry of home runs hit over the last couple years vs. the old days) it aint steroids , its livelier wood.<chuckle>

bottom line IMHO UL has determined the appropriate safety testing that all listed units must exceed, unlisted units, heck yeah , if someone wants to risk installing one, then nfpa 211 is a better guideline than "bubba's homemade heat" stoves hand written manual gives you. its not a trivial exercise to design a stove, make it safe, reliable, and efficient. the testing for UL approval is stringent, it isnt about emmissions in that test series, its pure safety, the stove , AND THE MANUAL both have to be approved, that means the clearances listed in the manual have to be approved as well.

here is the link https://www.hearth.com/econtent/index.php/articles/wood_stove_clearances_installing_it_safely?id=63_0_1_0_M1
 

BrotherBart

Modestorator
Staff member
Passing inspection is one part of it. Observation and common sense is another. With the 30-NC loading door sitting 11" behind the edge of an 8" raised hearth and an 18" two inch thick, can't burn it with a blow torch hearth extension in front of it that bad boy still throws some major heat down onto the carpet in front of the hearth pad from the big ass glass in that door. That is why until I get comfortable with it or change something there is a butt ugly Imperial stove board under the hearth extension that goes out four feet.

Code is one thing. Taking a look at how hot things get around the stove is another. And how comfortable you are with it. One fantastic square custom made oak coffee table may have to leave the area. Way past the clearance to combustibles but that sucker is getting too hot during deep season burns.
 

stoveguy2esw

Minister of Fire
good point, kinda like moving the leather couch to the other side of the room , not because its gonna burst into flames from 6 ft away from the stove , but the dry heat is gonna ruin the leather, the listed clearances take int account various floor surfaces , but they dont necessarily speak to the "non-combustion" issues that could come into play, like your table or the aforementioned leather furniture.
 
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elkimmeg

Guest
Bb there are code governing how close other combustible can be in relationship of that stove (IE That table furniture ect/ )

the distance is 48" you experience just confirmed the need for that code

Here is the situation you come in for a permit. In this discussion I inform you I will be enforcing the 18" distance to loading doors. I provide you a copy of that section of the code.

I do the inspection and there is 15.5" Should I pass that installation? You know from the beginning, I'm enforcing code your listing has referenced.NFPA 211
 

Gunner

New Member
Sep 20, 2006
851
Southern Ontario
He is the situation, I'll install my stove according to the mfg's tested clearances. If I get an inspector who wants to hang his hat on NFPA 211 I'll kick his ass outta the house before he has time to unholster his tape measure :lol:
 
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