Unsafe woodstove installation (C) Daniel Friedman Fire Clearances & Installation Standards & Codes for Coal Stoves, Pellet Stoves & Wood stoves
+ Fire clearance distance reduction using heat shields
     

  • FIRE CLEARANCES, WOOD & COAL STOVE FLUES - CONTENTS: What are the required Fire Clearances for Flues for Woodstoves & Coal stoves? Fire clearance distance specifications for wood stoves or coal stoves. Wood stove & pellet stove installation codes & standards, listings, labels, certifications. Wood stove or pellet stove heat shield construction & installation specifications. Examples of unsafe wood stove installations.
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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.

Green links show where you are. © Copyright 2015 InspectApedia.com, All Rights Reserved.

Fire Clearances for Flues for Woodstoves & Coal stoves

Unsafe woodstove installation (C) Daniel FriedmanOur 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.

Article Contents

Child safety: 36" safety zone around Wood Stoves & Pellet Stoves

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.

Specific Fire Safety Clearance Distances for Un-Certified Wood Stoves & Pellet Stoves

Free-standing fireplace installed by Daniel Friedman (C) Daniel Friedman 1975 - 2015In 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.

  • Un-certified woodstove clearance distances: 48" to combustibles at sides, rear, and corners as well as the "fueling" or or ash removal side of the the heater. This distance might be reduced to 36" with an approved heat shield.
  • Un-certified woodstove clearance distance: 60' above the stove top to the ceiling or any combustible above the heater.
  • Un-certified woodstove clearance distances when the stove has a sheet metal jacket or casing = 36" to combustibles

General Fire Safety Clearance Distances for Listed or Certified Wood Stoves & Pellet Stoves

Jotul No. 118 data tag showing fire clearance distances for this wood stove (C) Daniel FriedmanAt 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 from woodstove to unprotected surfaces or combustibles = 36" in any direction

    Typical clearance between a wood or coal fired heater and the nearest combustible surface is 36" unless approved heat shields have been installed.

    The free-standing fireplace (photo at page top) is less than 12" from wood paneling which is in turn installed on a wood-framed wall - this is an unsafe installation that should not be used.

    Note that drywall mounted on wood-framed walls is considered a "combustible wall" for clearance distance purposes.

    Note that some jurisdictions may require a greater distance between the wood or pellet stove and the ceiling.
  • Clearance from the woodstove vertical flue to unprotected wall surface = 18"

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:

The minimum clearance between any solid-fuel-burning appliance and combustible material (other than the floor), whether or not such material is covered with non- combustible material such as plaster, shall conform to Table 2: Clearances to Combustible Material for Appliances Using Solid-Fuel of CAN/CSA-B365-01, Installation Code for Solid-Fuel-Burning Appliances and Equipment , unless the appliance is certified for lesser clearances.

Certified appliances, accessories, components, and equipment, shall be installed in accordance with the manufacturer’s installation instructions. When a difference exists between the manufacturer’s installation instructions and the CAN/CSA-B365-01, Installation Code for Solid-Fuel-Burning Appliances standard, the manufacturer’s installation instructions shall govern.

And for non-certified appliances
Clearances for uncertified and certified appliances may be reduced in accordance with the clearance provisions of certified heat shields or if the requirements are satisfied as set out in Table 3: Reduction in Appliance and Ductwork Clearance from Combustible Material with Specified Forms of Protection of CAN/CSA- B365-01, Installation Code for Solid-Fuel-Burning Appliances and Equipment .
-
retrieved 11/18/2014, original source: http://www.municipalaffairs.alberta.ca/documents/ss/solidfuelpub-final.pdf

  • Flue or chimney clearance distances:

  • Wall or Ceiling Penetrations for single-wall stovepipes typically must have at least 18" of clearance to combustibles in all directions.

Wood stove with inadequate floor or hearth protection (C) Daniel Friedman Wood stove with inadequate floor or hearth protection (C) Daniel Friedman

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.

  • Floor Protection A non-combustible floor protector should extend at least
    • 18" on either side of the woodstove. Some codes permit 12" clearance from the side of the wood stove to the edge of the floor protection.
    • 18" in front of the woodstove
    • 6" of air space between woodstove bottom and floor protection system.
    • Canadian standards [cited below] recommend the following floor protection:

      Any combustible flooring or floor covering beneath a solid-fuel-burning appliance requires protection from hot embers that might fall during fire tending or ash removal.

      Combustible floors must be protected by a continuous, durable, non combustible pad made of a 0.38 mm (0.015 in) thick metal sheet , or a grouted ceramic floor-tile installed in accordance with the National Building Code of Canada shall be considered a durable pad. Floor protection pads must extend not less than 450 mm (18 in.) in front of the loading door and 200 mm (8 in.) beyond the other sides and back.

      And for non-tested heating appliances

      If acceptable to the authority having jurisdiction , non- tested appliances, must provide adequate floor protection which will depend on the height of the unit supported off the combustible floor structure. Necessary protection is based on the Mounting and Floor Protection section of CAN/CSA-B365-01, Installation Code for Solid-Fuel-Burning Appliances and Equipment .
      - retrieved 11/18/2014, original source: http://www.municipalaffairs.alberta.ca/documents/ss/solidfuelpub-final.pdf

Heat Shield Specifications for Wood Stoves & Pellet Stoves

There are two approaches to heat shield protection to reduce wood heater fire clearance distances

  1. A heat shield is attached to the wood heater itself: CSA Standard B365-1991 Table 3 p. 26 in discussing clearances for un-certified heaters specifies:

    Shielding consists of protection such as external jacketing or metal heat shield attached to the sides and rear of the appliance and spaced out at least 50 mm (2 inches) by non-combustible spacers, with a provision for air circulation at bottom and top.
  2. A heat shield is attached to nearby walls or ceilings.

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.

Watch out: providing an air space may be inadequate fire protection if air cannot circulate freely behind the heat shield. Avoid blocking the openings at the top or bottom a heat shield.

Percentage Woodstove Clearance Distance Reductions By Use of a Heat Shield

Jotul Woodstove installed by Paul Galow (C) Daniel FriedmanAt left is a Jotul woodstove that I (DF) traded to Paul Galow for a fancy wristwatch.

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

    1. Sheet metal heat shield, 29 gauge or heavier, with 7/8" (we recommend 1") air space (described below):
      • Reduce side & rear clearances by 67%
      • Reduce top clearance distance by 50%
    2. Non-combustible heat shield such as ceramic tile or equivalent, with 7/8" (we recommend 1") air space (described below):
      • Reduce side & rear clearances by 50%
      • Reduce top clearance distance by 33%
    3. Combined non-combustible heat shield as in #2 above, mounted on sheet metal backing as in #1 above. [You can see our combined sheet metal, noncombustible cement backer board and ceramic tile heat shield with air space in the photo at above left]
      • Reduce side & rear clearances by 67%
      • Reduce top clearance distance by 50%
    4. Brick heat shield at wall(s) with 7/8" air space between heat shield & wall
      • Reduce side & rear clearances by 50%
    5. Brick heat shield with metal backing (as above) with 7/8" air space as above
      • Reduce side & rear clearances by 67%

- Woodheat.org Ret: 11/16/2014 Original source: http://www.woodheat.org/clearances.html

Wood Stove or Pellet Stove Certification Labeling

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.

Wood stove permanent certification label Wood stove data tag, U.S. EPA

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.

EPA temporary wood stove label (C) InspectAPediaIt 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.

Wood stove / Pellet Stove Installation Standards & Fire Clearances

  • Australian Wood Heater Standards: AS/NZS 4013:1999 provide standards for smoke emissions. The Building Code for Australia also provides wood stove installation details and in Tasmania only wood stoves complying with the emissions standard above are permitted to be installed.
  • Canada Wood Stove Standards: contact CSA directly: Website: www.csa.ca or Tel: 800-463-6727. In Western Canada call 780-490-2007.

    Alberta's Municipal Affairs department has provided a helpful summary of Canadian standards for various types of heating appliances, heat shields, and related equipment from which we excerpt and expand below. - retrieved 11/18/2014, original source: http://www.municipalaffairs.alberta.ca/documents/ss/solidfuelpub-final.pdf
    • CAN/CSA B365-01, “Installation Code for Solid-Fuel-Burning Appliances and Equipment"
    • CAN/CSA-B366.1, central systems
    • CAN/ULC-S610, factory-built fireplaces
    • ULC-S627, space heaters;
    • ULC-S628, fireplace-inserts & hearth-mounted stoves
    • CAN/ULC-S629, factory-built chimneys
    • ULC-S632, heat shields
    • ULC-S635, lining systems for existing chimneys
    • CAN/ULC-S639, steel fireplace liners
    • CAN/ULC-S640, liners for new chimneys
    • ULC-S641, flue pipes
    • or the requirements of the authority having jurisdiction
  • New Zealand Wood Heater Standards: AS/NZS 4013:1999 provide standards for smoke emissions.
  • NFPA National Fire Protection Association, 1 Batterymarch Park, Quincy MA 02169, Website: http://www.nfpa.org/
    • NFPA Home Heating Safety Tips, [PDF] retrieved 11/17/2014, original source http://www.nfpa.org/~/media/Files/Safety%20information/
      Handouts%20in%20other%20languages/heatingsafetytips.pdf
    • NFPA Smoke Alarms at Home [PDF], retrieved 11/18/2014, original source
      http://www.nfpa.org/~/media/Files/Safety%20information/
      Safety%20tip%20sheets/SmokeAlarms.pdf
    • NFPA Alarmas de Incendio en el Hogar [PDF], retrieved 11/18/2014, original source
      http://www.nfpa.org/~/media/Files/Safety%20information/
      /Safety%20tip%20sheets/SmokeAlarmTipsSpanish.pdf
  • U.K. Wood Stove Certifications:
  • U.S. EPA,
    • CHIMNEY FIRES safety recommendations from the US CPSC concerning chimney fires
    • List of EPA-Certified Wood Heaters [PDF] meeting the 1988 Standards of Performance for New Residential Wood Heaters, November 2014, - retrieved 11/18/2014, original source: http://www.epa.gov/compliance/resources /publications/monitoring/caa/woodstoves/certifiedwood.pdf
  • Wood Heat Safety Woodheat.org Original source: http://www.woodheat.org/clearances.html

Examples of Unsafe Fire Clearances for woodstoves

Woodstove unsafe (C) Daniel Friedman Woodstove by couch (C) Daniel Friedman

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
at SOLAR COLLECTOR WOOD HOUSINGS.

Convert a Zero-Clearance Fireplace to a Woodstove Installation

Fireplace insert (C) Daniel FriedmanReader Question: who can install a woodstove where we have a zero clearance fireplace?

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

Reply:

We have moved this question and our reply to a separate article. Please
see WOOD STOVE INSTALL CONVERT

 

Continue reading at FIRE CLEARANCES INDOORS or select a topic from the More Reading links shown below.

Or see WOOD STOVE INSTALL CONVERT

Or see WOOD STOVE INSPECTION CHECKLIST [Document Image] for a safety checklist provided by State Farm® Insurance.

Suggested citation for this web page

FIRE CLEARANCES, WOOD & COAL STOVE FLUES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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