NFPA 211 Hearth Requirements

[thechimneysweep]

I just posted this in another thread, but I think this issue needs its own space, because people come to the forum for the straight dope, and I see some misinformation being passed along about this subject.

While it is true that NFPA recently changed its generic woodstove hearth extension requirement from 16" to 18", this doesn't mean that the tens of thousands of woodstoves that have been tested, listed and installed with 16" hearth extensions are unsafe.

It also doesn't mean that new installations must disregard the specific hearth extension listing in a stove's manual in favor of the 18" spec.

A stove's listing supercede's NFPA's generic requirements, which are intended for unlisted stoves: if you're installing an unlisted stove (an antique, or homemade stove for example), you need to follow the NFPA 211 clearance and hearth extension guidelines. If you're installing a listed stove, you're entitled to any clearance and hearth extension reductions specified in the installation manual.

 

[webbie]

Tom, I must respectfully disagree.

In many states and locales, the AHJ (Authority having jurisdiction) has the freedom to make such decisions. While I agree that they cannot make folks change existing installations, when it comes to new ones they have the right to require 2006 NFPA.

That's the way I read it - and I really doubt that any appeals board (where you go if you and the inspector disagree) would hold up your side of the argument.

There may be some gray area if the inspector issued a permit based on plans with the 16"...and then LATER asked for the 18", but just as with the Police, city hall is going to give the AHJ the benefit of the doubt.

 

[webbie]

Another note - keep in mind that the testing does not always establish the hearth extension.....rather the manufacturers and the lab spec the 16" BASED ON WHAT THE CURRENT NFPA at the time was. The 16 and 18 are largely arbitrary - that is, they are for spark protection mostly as opposed to heat, and they could have picked 15, 17, 19, 20 or another number and tested to it (and passed).

 

[thechimneysweep]

Craig, I've had my share of run-ins with the AHJ over the years, and agree that each local code authority can excercise code interpretation privileges. We deal with five different code authorities in our service area, and sometimes need to alter an installation because of a given code authority's interpretation of a given code spec.

However, a code authority's interpretation must be consistent, and I have fought and won several cases where it could be shown that an inspector's call was arbitrary.

For example, NFPA 211 calls for 36" clearance from a wood stove to an unshielded combustible backwall. If an inspector accepts a manufacturer's reduced backwall clearance listing for a given installation, but refuses to accept the reduced hearth extension listing specified in the same manual, I would call that arbitrary, and get that ruling reversed.

Since NFPA's 18" generic hearth extension came to be, I've asked all 5 of the code authorities we deal directly with for their take: all said if the stove is listed, they'll continue to go by the manufacturer's listing. I've discussed this matter with several colleagues, and none has had a manufacturer's hearth extension listing questioned.

In fact, the only inspector I've heard of in the country that requires 18" of hearth extension for stoves that are listed to 16" is Elkimmeg.

 

[webbie]

In fact, the only inspector I've heard of in the country that requires 18" of hearth extension for stoves that are listed to 16" is Elkimmeg.

He's probably the only one who knows about it!
:coolgrin:

But now there are two (the guy who posted in the original thread).....

I do think it is a bit misleading to refer to NFPA 211 as "generic", because in this case it is often the initial basis for the stove manufacturer and test lab in establishing this particular requirement (hearth extension).

Most reasonable inspectors....or uneducated ones....are usually fine with the owners manual.

My points are two:
1. With every day that goes by, more inspectors will know about the 18", more manuals will reflect this (stoves that are newly tested, etc.).
2. I also have won appeals against Building Officials. However, personally I would not expect to win one like this. My thought is that the board would say "it's 2008, and the installer or stove shop should, by now, know about the 2006 NFPA".

I 100% agree this is not a safety or "recall" issue and should not be looked at like aluminum wire, etc. - these ratings, in this case, are fairly arbitrary and NFPA is using one size fits all - when we all know there are vast differenced in door size and other factors.

Lastly, the inverse of this point is also something to think about. MANY manuals require much heavier (R-value) floor protection for a stove with legs of "x" inches thick....than NFPA does. So in these cases, installing to NFPA - but not the manual - could also get you failed. We have all seen stoves with stove pipe and wall clearances greater than 18" or 36" generic NFPA.

I'm with you in that a reasonable inspector would accept 16" if on the label and in the manual......I just would not want to fight it myself since they have a fairly good leg to stand on (2006 NFPA).

 

[thechimneysweep]

You make a good point: what about cases where the test lab found a need for greater clearances or hearth specs than called for by NFPA 211? Underlines the need for inspectors to go by the stove's listing, not NFPA 211, I'm thinking.

 

[jtp10181]

We go by the manual, IMO that's how it was tested and Quad thinks it is safe that way. Works for me. No inspectors have questioned it yet, but I don't know if any around here actually own the NFPA 211 book. Usually when we go to get a permit sometimes they are like.. "You want a permit for... what? Ohhhh... well we will just check this water heater box. Its the closest thing."

 

[pinewoodburner]

It appears that the NFPA 211 also calls for 18" on the side. Am I reading that correctly. That is alot more than the 8" listed in my stove specs.

 

[begreen]

Same thing. If the manufacturer has tested the stove and can certify the closer clearances, then that should rule. Many double wall stoves get down to 12" this way. However, I am seeing 18" side clearance in the clearances table for the Fireview.

Wall Protection
The Fireview Stove has been tested to UL Standards for clearances to combustible walls.
The minimum clearances to unprotected walls are as follows:
Minimum Clearances to Unprotected Combustible Walls:
From the Back: 30”
From the Sides: 18”

 

[pinewoodburner]

My fault, I was talking about the floor protection, 8" in front and 8" on the side without the door, 16" min with the door. 18" in front would extend the hearth another 10". Sorry about that, I was not refering to the side wall clearance.