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CHIMNEY INSPECTION DIAGNOSIS REPAIR
BACKDRAFTING HEATING EQUIPMENT
CARBON MONOXIDE - CO
CHIMNEY HEIGHT & CLEARANCE
CHIMNEY INSPECTION DIAGNOSIS REPAIR
COAL STOVE OPERATION & SAFETY
CREOSOTE FIRE HAZARDS
ENERGY SAVINGS in buildings
FIRE CLEARANCES INDOORS
FIRE CLEARANCES, WOOD & COAL STOVE FLUES
FIRE & SMOKE ODOR REMOVAL
FIREPLACES & HEARTHS
FIREPLACE CHIMNEY ROOF CLEARANCE
FIREPLACE DAMAGE & UNSAFE HEARTHS
FIREPLACE & WOODSTOVE CONTAMINANTS
HEATING COST SAVINGS METHODS
WOOD-OIL COMBINATION HEATERS
WOOD STOVE OPERATION & SAFETY
Woodstove fire clearance distance specifications:
This article describes fire safety distances required between wood stoves and coal stoves and the nearest combustible surface. We discuss child safety zones around wood and pellet stoves, the fire clearances for listed and un-listed wood or pellet stoves, and the construction and installation of a heat shield to reduce the required fire clearance distances around wood heating appliances.
The article includes standards for wood or pellet stove installations for various countries and it concludes with photos and descriptions of unsafe wood stove installations.
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Our photo (above) shows an unsafe wood fireplace installation that lacks adequate clearance from combustibles. Notice also that the connection between the fireplace top and the flue is upside-down and that considerable leakage has occurred out of the flue onto the fireplace top.
Some basic rule of thumb fire clearances for woodstoves are shown in the sketch at left. (Click to enlarge the image).
Watch out: Check with your local fire marshall about local building code requirements for fire-clearance distances before installing and using a wood stove, coal stove, or other auxiliary heat source. Making a mistake can lead to a dangerous building fire.
Use whatever means necessary to create a 36-inch safety zone around any heating equipment that can get hot enough to burn a child. Keep small children out of this space.
In the U.S. certification is monitored by the U.S. EPA who provide a List of EPA Certified Wood Heaters given below. The Canadian Standards Association (CSA) and the U.S. Wood Heat Safety Organization also provide consistent recommendations for wood stoves that are not carry a certification label. Certifying agencies and standards for other countries are given below.
[Click to enlarge any image]
Fire safety clearance distances are measured from the closest point of the outer surface of the heating appliance to the closest point of nearby wall, floor or ceiling or to other combustible materials that might be nearby. The wall finish surface, such as drywall is not considered in evaluating the heat resistance or fire safety of the heating appliance.
At left is a free-standing wood-burning fireplace installed by the author in the 1970's. Installation was incomplete - no adequate fire shielding was yet provided for this heater. I (DF) lived with this stove as a sole heat source in a different home in the early 1970's and can tell you it is not a design I recommend. I would not install this fireplace today.
Watch out: the free-standing fireplace shown is not a safe installation. While it had a damper controlling the flue to slow burn rate the front of the stove was open except for a screen - a big heat loser for the building as combustion can only be controlled by intelligence: don't build a big fire. And the installation as shown does not meet required clearances to combustibles.
At left is the permanently affixed certification and data tag from a Jotul No. 118 wood stove that has been in service for more than 20 years in New York. The company's data tag includes woodstove fire clearance distances as marked.
[Click to enlarge any image]
Watch out: Check with your local fire marshall about local building code requirements for fire-clearance distances before installing and using a wood stove, coal stove, or other auxiliary heat source.
Also check the specific fire clearance distance recommendations provided by the manufacturer of your wood burning appliance. Making a mistake can lead to a dangerous building fire. In some jurisdictions for certified woodstoves clearance distances permitted may be as follows:
Clearance distances such as those cited above can in some circumstances be reduced by using proper heat shields of proper material and with proper air spacing and mounting hardware: subject to approval by your local building code official or fire marshall and described below.
In most jurisdictions a building permit and fire safety inspections are required before a wood stove or coal stove can be installed. But we often find that a permit was not obtained and no inspections performed.
Warning: even when a wood or coal stove has been properly installed there are other fire and burn hazards, such as placement of kindling, papers, or furnishings too close to the appliance, chimney fires, and combustion air or (with coal stoves) carbon monoxide hazards.
The following wall and ceiling clearances from woodstoves and similar heating appliances is described by Canada's CSA:
Above we illustrate what happens if a wood stove or fireplace does not include an adequately-sized hearth or floor protection. It is just about impossible to open the heater to inspect, add wood, or do anything else without risking setting the carpeting or floor on fire. More unsafe hearths and floor damage are shown at FIREPLACES & HEARTHS.
There are two approaches to heat shield protection to reduce wood heater fire clearance distances
Wall-mounted Heat Shield Protection: A proper non-combustible fire-protective barrier for a wall-mounted includes a 1" air space between the barrier and the combustible wall.
Mounting hardware for heat shields: The non-combustible wall protection must use insulating and non-combustible mounting hardware that can not conduct heat from the woodstove or its flue to the combustible wall through the barrier.
Air circulation behind heat shields: If air cannot circulate freely behind the noncombustible wall protection the installation is unsafe and not acceptable. Most standards specify one-inch or in some cases 7/8" of air space behind the heat shield.
Paul installed air-spaced heat shields of ceramic tile mounted on fireproof board behind the stove and he added a heat shield (the silver contraption) on the side of the stove facing a bed just to slow down the heat in that direction.
More about this wood stove is at WOODSTOVE DRAFT CONTROL
That wood-box on the left side of the stove is a bit close in my OPINION. And the heat shield, really intended as a heat reflector to avoid overheating Mr. Galow's leg (shown in the photo) is itself constructed using a melange of reflective metal and combustible wood as a spacer and as a foot stand.
Watch out: as I've warned Paul, Even if no immediate fire or smoking wall is observed, use of a wood or other heating appliance too close to combustibles can lower their combustion point so that years later during use of the same appliance under what seem to be the same conditions, a fire may occur. See PYROLYSIS EXPLAINED for details.
In my OPINION this is not a safe heat shield. Like many wood stove users, P.G., the owner has chosen to exercise caution and attention for more complete and effective heat shielding - an approach that we've seen successful until a new, less informed or less cautious occupant uses the installation.
According to Wood Heat Safety Woodheat.org Original source: http://www.woodheat.org/clearances.html
Watch out: when purchasing a woodstove or pellet stove be sure that the unit carries a permanently affixed label certifying that it has been tested for safety by an independent testing laboratory.
The US EPA sketch at above left illustrates where you should find the permanent wood stove certification tag and what it looks like. This "EPA Sticker" is not a stick-on label despite the use of that term by some agencies.
It is typically a non-combustible metallic label that gives the date of manufacture of the wood or pellet stove and includes this text: "U.S. Environmental Protection Agency, Certified to Comply with July, 1988 particulate emissions standards."
Note that nothing in this certification comments directly on the safety of the heating appliance nor its fire safety clearance distances. Those data will generally appear in the wood stove's or pellet stove's installation instructions as well as in your local building codes.
A temporary label giving data about the wood heater's efficiency, smoke output in grams per hour, and heat output in BTU range per hour is also affixed to the stove when purchased.
An example temporary data tag for a non-catalytic wood stove is shown at above-right These data tags are distinct from the wood stove certification tag and give different information.
Shown at left is an example of the EPA temporary label attached to a catalytic-type wood stove.
Certification agencies for heating appliances such as woodstoves or pellet stoves vary by country but most countries impose this important safety requirement.
Below we give sources for wood stove and pellet stove installation and safety standards for various countries.
Above we illustrate two egregious examples of wood stove installations. The Jotl type woodstove (above left) is installed half in a weird (and improperly constructed) fireplace and half standing on carpeting.
The odd shape of the fireplace was creative but we suspect that it may not have performed well - another reason for adding the woodstove. This is an unsafe installation.
Placing a woodstove in a living room next to the couch (above right) is asking for a fire.
The process and temperatures under which wood deteriorates and becomes more readily combustible is also discussed
Convert a Zero-Clearance Fireplace to a Woodstove Installation
I'd like your opinion as to what type of contractor I need, or if we need one at all.
We have a 1990's Lindal log home with a heatilator fireplace installed. I believe this is a zero clearance fireplace with no actual masonry except for the faux rock surrounding it.
We would like to have a wood burning stove instead. Either a stove on the hearth with the chimney going back inside the fireplace and up the existing flue/pipe, or remove the entire heatilator fireplace. This is my choice and my husband votes for the prior.
If we remove the entire heatilator, I don't think there is any actual masonry inside the rectangular "chimney".... So, we don't know if this is a major construction project that needs a Mason to do it, or if this is a simple task and a fireplace shop could do it. (Of course we'd have to buy their wood stove.
Can you tell me what kind of company I should be dealing with to take this on? - S.D. 11/30/2014
We have moved this question and our reply to a separate article. Please
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Frequently Asked Questions (FAQs)
(Sept 19, 2011) Sally said:
do you have to change them out for example if someone had an oil burner and you wanted to install a wood stove ?
Yes Sally, different fuels and heating appliances may require different chimney types and dimensions.
See METAL CHIMNEYS & FLUES - home, for a guide to all of these.
(Oct 22, 2011) josh said:
A non-combustible metal heat shield reflects heat rather well provided it has been properly installed including with a circulating air space behind it, with out using connectors that conduct heat to building framing or other combustibles, and that fire clearances are still respected. Basically a heat shield lets you reduce but not eliminate fire clearance distances.
(Sept 20, 2012) mike said:
while you should have reviewed your design with your fire inspector as part of the required building permit requirement for putting in a chimney, wood stove, etc, and with further weaseling on my part because you don't say if this is a wood stove, fireplace, or what, nevertheless I caution that stone conducts heat, and even at comparatively low temperatures like 200f pyrolysis occurs and so there can be a fire hazard.
(Sept 30, 2012) keith said:
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