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Construction Tips and Standards

Before selecting or installing a hearth product, there are many things to consider.  First and foremost is the safe installation and venting of any fireplace, stove or gas log sets purchased.  The following information is provided as a “guideline only” to understanding the proper installation of any hearth product, but should not be considered instructions.  The HPBA recommends that all hearth products be installed by a National Fireplace Institute (NFI) Certified installer.  These trained professionals are versed in hearth installations and manufacturers specification.  To find an NFI installer, visit 

Best Practices for Woodburning Fireplace Installation

If installed properly and safely, there are few things as peaceful and relaxing as a woodburning fireplace.  Follow this link to the HPBA Best Practices for Woodburning Fireplace Installation.

Gas Log Set Installation

If your clients are tired of burning wood, but want to hold onto the ambience of their fireplace, a gas log set may be the answer.  Follow this link to the HPBA Gas Log Set Installation Guidelines.

Venting Your Hearth Product

Hearth products are vented in three ways: natural draft (vented through the roof), direct-vent, and vent-free. Below are the options for gas hearth appliances.  Follow this link to the HPBA Hearth Product Venting Guide.

A Guide Standard for Fireplaces, Chimneys, Vents

Because each jurisdiction is different, we cannot provide building and fire code information.  However, your local fireplace retailer will be able to provide you with that information.  If you would like to keep general information on hand, the National Fire Protection Association, developed the NFPA 211: Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances guide book that was developed through a consensus standards development process.  Chapter 4: General Requirements and Chapter 11: Fireplaces (excerpts only) follow and the entire publication can be purchased on

National Fire Protection Associatiion (NFPA) 211: Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances; 2006 Edition (EXCERPTS)

Reprinted with permission from NFPA 211- 2006, Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances, Copyright© 2005, National Fire Protection Association, Quincy, MA.  This reprinted material is not complete and official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety.


4.1* Sizing and Draft

4.2 Termination (Height)

4.3 Enclosure

4.4 Venting Systems in Ducts

4.5 Flue Lining

4.6 Caps and Spark Arresters for Chimneys and Vents



4.1* Sizing and Draft.

4.1.1 Minimum Performance. A chimney or vent shall be so designed and constructed to develop a flow sufficient to remove completely all flue or vent gases to the outside atmosphere.  Chimneys or vents shall be evaluated to ensure proper performance with respect to draft, creosote buildup, and condensation.  The venting system shall satisfy the draft requirements of the connected appliance(s) in accordance with the manufacturers' instructions or approved methods.

4.1.2 Mechanical Draft Systems. A listed mechanical draft system of either forced or induced draft design shall be permitted to be used to increase draft or capacity.  Where a mechanical draft system is installed, provision shall be made to prevent the flow of fuel to an automatically fired appliance(s) when that system is not operating.  The operation of a mechanical draft system shall not adversely affect the performance or safety of, or cause spillage of combustion products from, other combustion equipment operating within the same building.  Proper performance and safety of other combustion equipment shall be verified by testing prior to the mechanical draft system being put into service.  Such testing shall include operation of the mechanical draft system together with other exhaust equipment likely to operate simultaneously.  Mechanical draft systems of either forced or induced draft serving manually fired appliances shall be one of the following:

(1) A mechanical draft system that is an integral part of a listed appliance

(2) A solid fuel cooking appliance as addressed in NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations

(3)*An engineered mechanical draft system that includes the following provisions:

(a) The following detection and warning devices shall be installed and line voltage devices, when installed, shall be provided with a battery backup system:

i. A device that produces an audible and visible warning upon failure of the mechanical draft system. The device shall be activated by loss of electrical power supply or by operational failure of the mechanical draft system at any time while the mechanical draft system is switched on.

ii. A smoke detector and alarm installed and maintained in accordance with NFPA 72, National Fire Alarm Code. The detector shall be installed in the same room as the appliance served by the mechanical draft system.

iii. A listed carbon monoxide warning device installed in accordance with the manufacturer's instructions.

(b) The mechanical draft system shall be listed in accordance with UL 378, Standard for Draft Equipment, for use with the type of appliance and range of chimney service appropriate for the application. The mechanical draft system shall not cause or permit blockage of the flue or electrical hazard after exposure to a chimney fire or over fire conditions. The mechanical draft system shall be installed in accordance with the terms of the listing and the manufacturer's instructions.

(c) The mechanical draft system shall be sized to maintain draft within the range specified by the appliance manufacturer.

4.1.3 Natural Draft Sizing. Chimneys serving incinerators or other process equipment where the combustion process cannot be stopped completely by fuel shutoff alone shall be sized for natural draft conditions.  Where air pollution control devices or other devices in the chimney system require a mechanical draft system, the chimney system shall be so arranged that, upon a power failure, the natural draft chimney alone can satisfactorily remove the products of combustion until the combustible material is completely consumed.

4.1.4 Forced/Induced Draft Systems. Forced draft systems and all portions of induced draft systems under positive pressure during operation shall be designed and installed to be gastight or to prevent the leakage of combustion products into a building.

4.1.5 Natural Draft Vent Connectors. Vent connectors serving appliances vented by natural draft shall not be connected into any portion of mechanical draft systems operating under positive pressure.

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4.2 Termination (Height).

Chimneys and vents shall terminate above the roof level in accordance with the requirements of this standard and as illustrated in Figure 4.2(a) and Figure 4.2(b).

FIGURE 4.2(a)  Chimney or Vent Termination Less Than 10 ft (3.1 m) from Ridge, Wall, or Parapet.

FIGURE 4.2(b)  Chimney or Vent Termination More Than 10 ft (3.1 m) from Ridge, Wall, or Parapet.

4.2.1  Masonry chimneys shall extend above the highest point at which they pass through the roof of a building by at least the distance specified in Table 7.2, Column VI, and shall also extend at least the specified distance above any portion of any structure within the specified proximity (measured horizontally from the vertical chimney line) in Table 7.2, Column VII.

4.2.2  Natural draft chimneys and vents shall not terminate at an elevation less than 5 ft (1.53 m) above the flue collar or the highest connected draft hood outlet.

Exception: As provided in Section 10.7.

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4.3 Enclosure.

4.3.1 General. Interior residential chimneys shall be enclosed where they extend through closets, storage areas, or habitable spaces where the surface of the chimney could come into contact with persons or combustible materials.

4.3.2 Clearance. The space between the chimney and the enclosure shall be at least the minimum air space clearance specified in this standard (see Table 7.2) or the clearance specified in the manufacturer's instructions for listed chimneys.

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4.4 Venting Systems in Ducts.

4.4.1 Circulating Air Ducts and Plenums. No portion of a venting system shall extend into or pass through a dedicated circulating air duct or plenum.

4.4.2 Above-Ceiling Spaces. Where a venting system passes through a space above a ceiling used as a return air plenum, it shall be installed according to one of the following methods:

(1) With joints within the above-ceiling return air plenum sealed airtight in a manner approved by the manufacturer of the venting system

(2) As a listed positive-pressure venting system

(3) Non-airtight venting system installed with no joints or fittings located within the above-ceiling return air plenum

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4.5 Flue Lining.

4.5.1 Resistance Equivalency. Castable or plastic refractories used to line chimneys or connectors shall be the equivalent in resistance to heat and erosion by flue gases to that of the fireclay brick.

4.5.2 Lining Support. Lining made of castable or plastic refractories shall be secured to the supporting walls by anchors made of corrosion-resistant steel capable of supporting the refractory load at 1500°F (816°C).

4.5.3 Space Surrounding Liner or Vent. The remaining space surrounding a chimney liner, gas vent, special gas vent, or plastic piping installed within a chimney flue shall not be used to vent another appliance.

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4.6 Caps and Spark Arresters for Chimneys and Vents.

4.6.1 Design. Chimney or vent caps, where required for the termination of chimneys or vents, shall be designed to prevent the entry of rain, snow, birds, and other animals.

4.6.2 Screening. Screening material attached to chimney or vent caps to prevent the entry of animals and insects shall not adversely affect the chimney or vent draft.

4.6.3 Spark Arresters.  Spark arresters, where required by the AHJ for chimneys attached to solid fuel–burning equipment, shall meet the following requirements:

(1) The net free area of the arrester shall be not less than three times the net free area of the outlet of the chimney flue it serves.

(2) The arrester screen shall have heat and corrosion resistance equivalent to 19 gauge [0.041 in. (1.04 mm)] galvanized steel or 24 gauge [0.024 in. (0.61 mm)] stainless steel.

(3) Openings shall not allow the passage of spheres having a diameter larger than ½ in. (12.7 mm) or block the passage of spheres having a diameter of less than 3/8 in. (9.5 mm).

(4) The spark screen shall be accessible for cleaning, and the screen or chimney cap shall be removable to allow cleaning of the chimney flue.  Where part of a listed chimney termination system, spark arresters shall be constructed and installed in accordance with the listing.

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11.2* Masonry Fireplaces.

11.2.1 Construction.  Fireplaces shall be constructed of solid masonry units or of reinforced portland or refractory cement concrete.  Masonry fireplaces shall be supported on foundations of one of the following:

(1) Masonry

(2) Reinforced portland cement concrete

(3) Refractory cement concrete

(4) Other noncombustible constructions having a fire resistance rating of not less than 3 hours, provided such supports are adequate for the load  Footings for masonry fireplaces and their chimneys shall be constructed of concrete or solid masonry at least 12 in. (305 mm) thick and shall extend at least 6 in. (152 mm) beyond the face of the fireplace or foundation wall on all sides.  Footings shall be founded on natural undisturbed earth or engineered fill below frost depth.  In areas not subject to freezing, footings shall be at least 12 in. (305 mm) below finished grade.

11.2.4 Steel Fireplace Units.  All wood beams, joists, studs, and other combustible material shall have a clearance to masonry fireplaces as follows:

(1) Not less than 2 in. (51 mm) from the front faces and sides

(2) Not less than 4 in. (102 mm) from the back faces of masonry fireplaces (See Figure  

 FIGURE  Fireplace Clearance to Combustible Material.  Woodwork, such as wood trim, mantels, and other combustible material, shall not be placed within 6 in. (152 mm) of a fireplace opening.

11.3.1  Masonry fireplaces shall have hearth extensions of brick, concrete, stone, tile, or other approved noncombustible material wholly supported by and integral with the chimney structure, and a minimum 4 in. (102 mm) clearance shall be maintained directly below the underside.

 FIGURE 11.3.3  Fireplace Hearth Extension Requirements.

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