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Maine State LibraryDigital MaineFire Marshal Documents Public Safety2005Recommended Standards for the Installation ofWoodburning Stoves 2005Maine Office of the State Fire MarshalFollow this and additional works at: https://digitalmaine.com/fmo_docsThis Text is brought to you for free and open access by the Public Safety at Digital Maine. It has been accepted for inclusion in Fire Marshal Documentsby an authorized administrator of Digital Maine. For more information, please contact statedocs@maine.gov.Recommended CitationMaine Office of the State Fire Marshal, "Recommended Standards for the Installation of Woodburning Stoves 2005" (2005). FireMarshal Documents. 2.https://digitalmaine.com/fmo_docs/2RECOMMENDED STANDARDS for the INSTALLATION of WOODBURNING STOVES      Prepared By  Office of State Fire Marshal   Maine Office of Energy Resources 52 State House Station    55 Capital Street Augusta, ME 04333     Augusta, ME 04330   RECOMMENDED STANDARDS FOR THE INSTALLATION OF WOOD BURNING STOVES       This guide has been prepared to inform the people of the State of Maine of the recommended standards for the installation of wood burning stoves.  These standards have been approved by the Office of State Fire Marshal in accordance with the National Fire Protection Association’s standards.        These standards cover all wood burning appliances with the exception of on-site constructed masonry stoves and fireplaces; stoves with water jackets or coils; and wood fueled central heating systems utilizing pipes, ducts, or similar distribution systems.  Stoves for use in mobile homes should be specifically listed for such use.  All listed wood burning stoves should be installed according to the manufacturers’ recommendations.      DEFINITIONS      APPROVED:  Acceptable to the authority  DRAFT:  The natural force which conducts having jurisdiction.      smoke, hot air, and other gases to the outside ASBESTOS MILLBOARD:  A soft  atmosphere. insulating board made with compressed   FIRE RESISTANT INSULATING BOARD: asbestos fibers capable of being cut with knife Listed or approved materials suitable for  or hand saw.      protecting combustible surfaces. CHIMNEY:  A vertical shaft enclosing one or FLUE:  A tube, pipe, or shaft for passage of  more flues for conveying smoke, hot air, and  smoke, hot air, gas, etc., as in a chimney. other gases to the outside atmosphere.  FLUE COLLAR:  That portion of an appliance CHIMNEY CONNECTION:  The conduit  designed for attachment to the chimney connector. connecting the wood stove with the vertical  FLUE LINER:  A material which resists high flue (generally stovepipe).     temperatures and is designed specifically for lining CIRCULATING STOVE:  A wood burning chimneys or connectors.  appliance surrounded by an outer jacket with LISTED:  Equipment or materials which meet  openings at the top and bottom so that room   nationally recognized standards or tests which  air passes between the stove and the jacket.  determine suitability of usage in a specified COMBUSTIBLE WALL:  Any wall section manner. that has the potential to burn.  Only solid   RADIANT STOVE:  Any wood burning appliance masonry or corrugated steel walls are con-  not designed as a circulating stove.  sidered non-combustible.  Merely covering a THIMBLE:  Liner for the passageway where the  wood studded wall with a non-combustible  chimney connector enters the chimney flue. material does not constitute a non-combustible WOOD BURNING APPLIANCE:  Any free- wall.       standing unit which utilizes wood as a fuel to  COOK STOVE:  A wood burning stove used produce heat.  This includes stoves installed into for cooking which includes an oven and surface fireplace openings. heating areas.    1  TABLE OF CONTENTS     I. Clearances from wood burning stoves   a.  To walls and ceilings b.  To floors    II. Chimney connectors   a. Clearances from connectors b. Installation    III. Chimneys  a. Chimney draft b. Multiple connections c. Listed pre-fabricated metal chimneys           IV.       Organizations governing the installation of wood burning equipment                 2       I. CLEARANCES FROM WOOD BURNING STOVES   Stoves must be provided with adequate clearances from combustible materials.  The minimum clearances needed for safety are specified in National Fire   Protection Association Standard # 211, Chimneys, Fireplaces, Vents and   Solid Fuel Burning Appliances, 2003 Edition.  a. Clearances to Walls and Ceilings  Clearances indicated in Table 1 (below) are the minimum clearances from wood burning stoves to unprotected combustible wall and ceiling surfaces.      TABLE 1 Minimum Clearances from Wood Burning Stoves to Combustible Surfaces with No Added Protection     Radiant  Circulating       Cookstove Clay lined Firepot     Cookstove Unlined Firepot Stovepipe    Listed    Stoves  Ceiling        36”           36”              30”            30”       18”   Install According to  Manufacturers Recommendations  Front        36”           24”         18”  Side        36”           12” Firing side 24” Opposite side 18” Firing side 36” Opposite side 18”       18”  Rear        36”           12”              24”            36”        18”  NOTE Stoves may be installed with clearances less than those specified in Table 1 provided the combustible material is protected as described in Table 2 or Figure 1.    3  TABLE 2 Minimum Clearances from Wood Burning Stoves with Specified Forms of Protection ( See Footnotes )     Clearance reduction applied to and covering all combustible surfaces within the distance specified as required clearance with no protection   Maximum allowable reduction in clearance (%)   Where the required clearance with no protection is 36 in. the clearances below the minimum allowable clearances.  For other required clearances with no protection, calculate minimum allowable clearances from maximum allowable reduction.       As Wall Protector As Ceiling Protector    As Wall Protector (%)  As Ceiling Protector (%)           inches          inches    (a) 3 1/2 in. thick masonry wall without ventilated air space       33   -               24   -   (b)   ½  in. thick noncombustible insulation         board over 1-in. glass fiber or mineral wool         batts without ventilated air space      50   33              18   24   (c)    0.024-in., 24 gauge sheet metal over 1-in. glass          fiber or mineral wool batts reinforced with wire          or equivalent, on rear fact with ventilated air          space      66    50               12    18    (d)   3 ½ in. thick masonry wall with ventilated air         space      66  -             12  -  (e)   0.024-in., 24 gauge sheet metal with ventilated        air space      66  50             12  18     (f)   ½ in. thick noncombustible insulation board        with ventilated air space      66  50             12  18  (g)   0.024-in., 24 gauge sheet metal with ventilated         air space over 0.024-in. 24 gauge sheet metal         with ventilated air space      66   50              12   18   (h)   1-in. glass fiber or mineral wool batts sandwiched         between two sheets 0.024-in., 24 gauge metal with        ventilated air space       66    50               12    18                 Table 2 Guidelines and Details continued on next page:    4 Table 2 Guidelines and Details  Notes:  1.  Spacers and ties shall be of noncombustible material.  No spacers or ties shall be       directly behind appliance or conductor.    2.  With all clearance reduction systems using a ventilated air space, adequate air       circulation shall be provided as described in section 9-6.2.4 of NFPA # 211.  There       shall be a least 1 in. between the clearance reduction system and combustible walls       and ceilings for clearance reduction systems using a ventilated air space.    3.  Mineral wool batts (blanket or board) shall have a minimum density of 8 lb/ft³ and          have a minimum melting point of 1500˚F (816ºC).  4.  Insulation material used as part of clearance reduction system shall have a thermal      conductivity of 1.0 (Btu-in.)/(ft²-hr-ºF) or less.  Insulation board shall be formed of       noncombustible material.    5.  If a single-wall connector passes through a masonry wall used as a wall shield, there      shall be at least ½ in. (13mm) of open, ventilated air space between the connector and      the masonry.    6.  There shall be at least 1 in. (25.4 mm) between the appliance and the protector.  In no      case shall the clearance between the appliance and the wall surface be reduced below      that allowed in this table.    7.  Clearances in front of the loading door or ash removal door, or both, of the appliance      shall not be reduced from those in Section 9-5, NFPA 211.  8.  All clearances and thickness are minimums; larger clearances and thickness shall      be permitted.    9.  To calculate the minimum allowable clearance, the following formula can be used:      Cr = Cn x [1 – (R/100].  Cr is the minimum allowable clearance, Cn is the       required clearance with no protection, and R is the maximum allowable reduction in      clearance.   10. Refer to Figures 9-6.2.1(e) and 9-6.2.1 (f), NFPA 211, for other reduced clearances using materials found in (a) through (h) of this table.        5                                                             "A" equals the required clearance with no protection as specified in Table 1. b.  "B" equals the reduced clearance permitted in accordance with Table 2.   The protection, applied to the construction using combustible material, should extend far enough in each direction to make “C” equal to “A”. Clearances To Floors General Requirements Residential-type solid fuel-burning appliances that are tested and listed by a recognized testing laboratory for installation on floors constructed of combustible materials shall be placed on floors in accordance with the requirements of the listing and conditions of approval. Such appliances that are not listed by a recognized testing laboratory shall be provided with floor protection in accordance with the provisions of 9-5.1.2 or 9-5.1.3 of NFPA # 21 1. Exception: Residential-type solid fuel-burning appliances shall be permitted to be placed without floor protection in any one of the following manners: (a) On concrete bases adequately supported on compacted soil; crushed Rock, or gravel (b) On concrete slabs or masonry arches that do not have combustible materials attached to the underside. (c) On approved assemblies constructed of only noncombustible materials and having a fire resistance rating of not less than 2 hours, with floors constructed of noncombustible material (d) On properly stabilized ground that can support the load of the Appliance Any floor assembly, slab, or arch shall extend not less than 18 in. (457 mm) beyond the appliance on all sides. See Table Below for Standard Floor Clearances: 6  FLOOR CLEARANCES FOR LISTED AND UNLISTED APPLIANCES                                                 FLOOR CLEARANCES         Length of Stove Leg            Floor Clearance and Protection          Less than 2 inches                 Fire resistant floor              2 – 6 inches                    Combustible floor protection by               4 inches of hollow masonry, laid               to provide circulation through the               masonry layer, covered by                24-guage sheet metal.              Over 6 inches                   Combustible floor protected by                2 inch thick masonry, placed over               a sheet of 24-gauge sheet metal.      • Listed fire-resistant insulating board can be installed according to the  manufacturer’s recommendations.           7  II. CHIMNEY CONNECTORS   A chimney connector links a stove to the chimney flue.  Chimney connectors  should be made from steel of minimum 24 gage thickness.  Lower gage numbers  indicate thicker stovepipe.    a. Clearances from Connectors   The clearance from a chimney connector to a combustible material  should be not less than three times the diameter of the connector.   Where the combustible material is protected, the clearance may be reduced to that indicated in Figure 1.    There are three methods for passing a chimney connector through a combustible wall.  Figures 2, 3, & 4 illustrate these methods.  In Figure 2 sheet metal or metal lathe and plaster finish may be used.  When installing as illustrated in Figures 2 & 3, the distance from the connector to combustible materials must be equal to three times the diameter of the connector.                                    FIGURE 2                                                        FIGURE 3                       8         Try to avoid passing a connector pipe through an interior wall.  If this   must be done, use a ventilating thimble (See Figure 4).  The thimble    diameter must be at least 12 inches larger than that of the stovepipe, thus    giving at least 6 inches of metal-lined, ventilated clearance.  If you do not    use a thimble, the clearance must be three times the pipe diameter.    A 6 inch pipe would need a 42 inch diameter hole cut through a   combustible wall.   FIGURE 4            Listed solid fuel pre-fabricated metal chimneys can also be used to pass through  a combustible wall when installed according to manufacturers’ recommendations.       9  b. Connector Pipe Installation   *  Keep the connector pipe as short as possible.  It should be no longer      than 75% of the vertical chimney height above the thimble where the      connector pipe enters the chimney.   *  The stovepipe should be straight as well as short.  Use no more than       two right-angle bends in the stovepipe installation.  Additional bends       cause soot and creosote to collect in the stovepipe or chimney, block       flue gas flow, and increase the danger of fire.   *  The connector pipe’s horizontal runs should rise ¼” for each foot of       pipe, with the highest point being at the thimble.     *  When joining the pipe, overlap the joints at least two inches, with the       crimped end pointing down to prevent creosote drips or leaks.  Secure       each joint with three sheet metal screws.  A fireproof sealant may be        used in addition.     *  All connector pipe joints should fit snugly, including connections with       the stove and thimble.  The connector pipe must not stick into the        chimney flue itself because this would hamper the draft.     *  Connector pipe should not pass through ceilings.  Factory built,        listed, all-flue chimneys should be utilized when passing through       ceilings.  Follow manufacturers’ installation instructions for these       chimneys.     *  Connector pipe should not pass through closets.  A closet fire could       smolder and spread undiscovered.     III. CHIMNEYS   The condition of a chimney should always be carefully evaluated before   considering the installation of a wood-burning appliance.  Beware of cracks,   deteriorated mortar, and unsealed openings in any chimney before attaching a  wood burning unit to it.    a. Chimney Draft  For sufficient draft a chimney should extend at least two feet higher than any portion of the building within ten feet horizontally from it (See Figure 5).  The flue area should not be smaller than the largest  connector pipe plus 50% of the additional area of a second connector entering the same flue.                                                         10 FIGURE 5        b. Multiple Connections  More than one wood burning appliance should not be connected to a  common flue.  A chimney connector should not be connected to a flue serving a fireplace or an oil furnace.  They should have their own individual flues.    One reason for this is that the sparks can enter the house through a fireplace opening serving a woodstove elsewhere along the line.  Both a fireplace opening and an oil furnace’s barometric damper will furnish large quantities of air to their flues.  In the event of a chimney fire, this will hamper any attempts to extinguish the fire by restricting airflow to the flue.  Using a wood-burning stove on a flue serving an oil furnace may also reduce the efficiency of the oil furnace, due to the change in draft characteristics of the flue.  Multiple connections sometimes result in insufficient draft.  If two or more stoves are connected to the same chimney flue, despite the recommendations against doing so, the connectors must enter the chimney at different elevations.        11  c. Listed Solid Fuel Pre-Fabricated Metal Chimneys  The use of pre-fabricated metal chimneys listed for installation with solid fuel heaters (not furnaces) are within the guidelines of the State Standard.  Care should be taken, however, with the use of such chimneys to avoid creosote accumulation and the associated potential danger of a chimney fire.  Air-controlled wood burning appliances should be operated in accordance with manufacturers’ instructions to reduce the potential for creosote build up.  Pre-fabricated metal chimneys can break down under the intense heat of a chimney fire, resulting in possible structural fire damage.  They should always be installed in accordance with the manufacturers’ recommendations.     IV. ORGANIZATIONS GOVERNING THE INSTALLATION OF WOOD  BURNING EQUIPMENT   Certain Maine communities have ordinances governing the installation of wood  burning equipment. Always check with your local Fire Department or Building   Inspector before attempting installation.  It is also important to consult with your   insurance company regarding any restrictions they may have on wood burning   appliance installation.  All installations in public buildings must meet standards  set by the Office of State Fire Marshal.     The wood burning appliances listed below are not covered by this recommended   standard.  For information on their installation, refer to the appropriate agency.       When Installing:    Consult With:  Site Built Masonry Flues and Fireplaces   Office of State Fire Marshal  Wood Fueled Furnaces or Boilers   Oil and Solid Fuel Burner  Technicians Licensing Board  Wood Burning Units with Water Jackets or Coils  Plumbing Code Enforcement Officers  Listed Wood Fueled Mobile Home Heaters   State Manufactured Housing Board or Office of State Fire Marshal  Listed Wood Burning Stoves   The manufacturers’ installation recommendations    12 

Recommended Standards for the Installation of Woodburning Stoves 2005

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Recommended Standards for the Installation of Woodburning Stoves 2005

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