Fireplace / Chimney Code Requirements CABO One and Two Family Dwelling Code

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1 Q: How far does a chimney have to extend above a roof? Section 1001 Masonry Chimneys ermination. Chimneys shall extend at least 2 feet (610 mm) higher than any portion of the building within 10 feet (3048 mm), but shall not be less than 3 feet (914 mm) above the point where the chimney passes through the roof. 3'-0" min 10'-0" min 24" min 10'-0" min 24" min

2 Q: What are the requirements for clearances from combustible framing members to masonry fireplaces/chimneys? Section 1001 Masonry Chimneys Chimney clearances. A portion of a masonry chimney located in the interior of the building or within the exterior wall of the building shall have a minimum air space clearance to combustibles of 2 inches (51 mm). Chimneys located entirely outside the exterior walls of the building, including chimneys that pass through the soffit or cornice, shall have a minimum air space clearance of 1 inch (25 mm). he air space shall not be filled, except to provide firestopping in accordance with Section Exception: Masonry chimneys equipped with a chimney lining system listed and labeled for use in chimneys in contact with combustibles in accordance with UL 1777, and installed in accordance with the manufacturer s installation instructions, are permitted to have combustible material in contact with their exterior surfaces. However, this shall not eliminate the requirement for noncombustible firestopping in accordance with Section Section 1003 Masonry Fireplaces Fireplace clearance. Wood or combustible framing shall not be placed within 2 inches (51 mm) of the outside face of a masonry fireplace and not less than 6 inches (153 mm) from the inside surface of the nearest flue lining. Wood framing and other combustible material shall not be placed within 2 inches (51 mm) of the back surface of a masonry fireplace.

3 Q: What are the requirements for hearths and hearth s? Section 1003 Masonry Fireplaces material. s shall be of masonry or concrete at least 2 inches (51 mm) thick and supported by noncombustible materials and reinforced to carry its own weight and all imposed loads. he hearth shall be readily distinguishable from the surrounding floor. Combustible forms and centers used during the construction of the hearth shall be removed after the construction is complete. Exception: When the bottom of the firebox opening is raised at least 8 inches (203 mm) above the top of the hearth, a hearth of not less than 3/8 inch thick (9.5 mm) brick, concrete, stone, tile or other approved noncombustible material may be used he hearth and the hearth shall extend a minimum of 36 inches (914 mm) from the back of the firebox to the end of the hearth. s shall extend at least 16 inches (406 mm) in front of and at least 8 inches (203 mm) beyond each side of the fireplace opening. Where the fireplace opening is 6 square feet (0.557 m 2 ) or larger, the hearth shall extend at least 20 inches (508 mm) in front of and at least 12 inches (305 mm) beyond each side of the fireplace opening. Less than 6 sq. ft. 8" min 16" min 8" min slab thickness 20" min 36" min. Masonry or concrete 2" min. thickness (self supporting) 6 sq. ft. or more Brick Firebox Sectional Side View on Wood Floor 12" min 20" min 12" min

4 Q: What are the required clearances to combustible woodwork and mantels around a fireplace opening? Section 1003 Masonry Fireplaces Combustible materials. Woodwork or other combustible materials shall not be placed within 6 inches (153 mm) of a fireplace opening. Combustible material within 12 inches (305 mm) of the fireplace opening shall not project more than 1/8 inch (3.2 mm) for each 1 inch (25 mm) distance from such opening. CROSS SECION OF MANEL Also applies to mantel above fireplace opening. 2" clearance min. wallboard Masonry Wood studs wallboard Wood trim or other combustible material Fireplace opening Projection line Combustible trim shall not extend beyond projection line when it is within 6-12" of fireplace opening. 1/8" projection of combustible material permitted for each inch distance from fireplace opening. 3/4" max projection at 6" from fireplace opening progresses to: 1 1/2" max projection at 12" from fireplace opening Drawings are for illustrative purposes only. Do not scale. 6" min clearance from opening. No combustibles permitted Front of mantel 12" from opening Beyond 12 " combustible materials not regulated.

5 Q: Does a fireplace require an exterior air supply? Yes Section 1006 Exterior Air Supply Exterior air. Factory-built or masonry fireplaces covered in this chapter shall be equipped with an exterior air supply to assure proper fuel combustion Exterior air intake. he exterior air intake shall be capable of providing all combustion air from the exterior of the dwelling or from spaces within the dwelling ventilated with outside air, such as crawl or attic space. he exterior air intake shall not be located within the garage of the dwelling. he exterior air intake shall be covered with a corrosion-resistant screen of 1/4 inch (6.4 mm) mesh Passageway. he combustion air passageway shall be a minimum of 6 square inches (3870 mm 2 ) and not more than 55 square inches (0.035 m 2 ) Inlet. he exterior air inlet is permitted to be located in the sides of the firebox chamber, or within 24 inches (610 mm) of the firebox opening on or near the floor. he inlet shall be closable and designed to prevent burning material from dropping into concealed combustible spaces.

6 Q: What are the requirements for factory built fireplaces? Section 1004 Factory-Built Fireplaces Installation. Factory-built fireplaces that consist of a firechamber assembly, one or more chimney sections, a roof assembly and other parts as tested and listed as an assembly by an approved agency may be installed when complying with all the following provisions: 1. he fire chamber assembly is installed to provide clearance to combustible materials not less than set forth in the listing. 2. he chimney sections are installed to provide clearance to combustible material not less than specified in the listing and if the fireplace chimney extends through floors and ceilings, factory-furnished firestops or firestop spacers shall be installed. Portions of chimneys which extend through rooms or closets are to be enclosed to avoid personal contact, contact of combustible material, and damage to the chimney. 3. s shall not be less than 3/8-inch thick (9.5 mm) asbestos, hollow metal, stone, tile or other approved noncombustible material. Such hearth s may be placed on combustible subflooring or finish flooring. he hearth shall be readily distinguished from the surrounding floor. 4. s shall extend not less than 16 inches (406 mm) in front of and at least 8 inches (203 mm) beyond both sides of the fireplace opening. 5. Factory-built fireplaces shall be installed in accordance with their listing and the manufacturer's installation instructions. 6. he supporting structure for a hearth shall be at the same level as the supporting structure for the fireplace unit unless otherwise authorized by the listing. Section 1002 Factory-Built Chimneys General. Factory-built chimneys shall conform to the conditions of their listing and the manufacturer's instructions. Factory-built chimneys that are listed as part of an assembly with factory-built fireplaces shall conform to Section

7 Q: What are the requirements for factory built fireplace stoves (wood burning stoves)? Section 1005 Factory-Built Fireplace Stoves General. Factory-built fireplace stoves, consisting of a freestanding fire chamber assembly, that have been tested and are listed by a nationally recognized testing laboratory, shall be installed in accordance with the requirements of said listing and the manufacturer's instructions. he supporting structure for a hearth shall be at the same level as the supporting structure for the fireplace unit.

8 Q: What are the minimum requirements for corbeling of masonry chimney walls? Section Masonry Chimneys Re Section Corbeling. Corbeling of masonry chimney walls is permitted within certain limitations. When the corbel is used for the support of a chimney built into the wall, the maximum projection for each course is limited to the lesser of one-half the unit height or one-third the unit depth, as shown in Figures 604.3a and a. Masonry chimneys must not be corbeled more than 6 inches (153 mm) from a wall or foundation, nor be corbeled from a wall or foundation which is less than 12 inches (305 mm) in thickness, unless the corbel projects equally on both sides, as shown in Figure b. D H Max. corbel 1/3 D or 1/2 H of unit, whichever is less Fig a Masonry Corbeling Limitations Per Course D (depth) Fireclay liner Airspace 4" solid masonry units Fireclay liner Airspace 4" solid masonry units 1/2 H or 1/3 D, whichever is less H (height) 12" min. 6" max. corbel t 1/2 t max. corbel Fig a Individual Corbels Fig b Corbeling from Foundation Wall

9 Section 1003 Masonry Fireplaces See able on next page for dimensions and requirements Bond beam K Mortar cap 2'-0" min. Masonry cap Brick E Block P Effective flue area R Clearance 10'-0" min. L Bond beam K Flashing 8" Width of fireplace opening B Plan view Flue lining S Anchorage Mortar cap Bond beam K Bond beam K J Horizontal reinforcing ties S Detail for full masonry wall Anchorage 2'-0" min. Clearance R 10'-0" min. Flashing Horizontal reinforcing ties Vertical reinforcing 1 1/2" min. grout between 4" concrete masonry and clay flue lining J H Wall M thickness N Parge with mortar Veneer tie clearance R S Anchorage 2 1/2" bolts each strap Anchor strap Flue liner 6" min. G Smoke chamber H Vertical reinforcing E A Firebox wall thickness slab thickness Ash dump optional clean out Footing width 1/2" min. L Lintel 20" min firebrick 8" min. F C D slab reinforcing hermal distance 21" min. Fireplace opening height 18" min. grade Measure height of freestanding fireplace from top of footing R 1/2" min. Footing depth For SI: 1 inch = 25.4 mm Clearance Lintel C F 20" min. 8" min. Horizontal reinforcing ties 4" thick masonry units Vertical reinforcing 20" lap if spliced to footing dowels Firebox wall thickness Bars in concrete footing J H E Footing width 6" around free standing fireplace Natural grade Brick Firebox and Chimney Sectional Side View on Wood Floor Figure Fireplace and Chimney Details Brick Firebox and Block Chimney Sectional Side View on Concrete Slab Drawings are for illustrative purposes only. Do not scale or submit as plans for permit. 1

10 Section 1003 Masonry Fireplaces ABLE REQUIREMENS FOR MASONRY FIREPLACES AND CHIMNEYS IEM LEER 1 REQUIREMENS slab thickness A 4" B 8" fireplace opening < 6 sq. ft. (each side of opening) 12" fireplace opening 6 sq. ft. C 16" fireplace opening < 6 sq. ft. (front of opening) 20" fireplace opening 6 sq. ft. slab reinforcing D Reinforced to carry its own weight and all imposed loads. hickness of wall of firebox E 10" solid brick or 8" where a firebrick lining is used. Joints in firebrick 1/4" max. Distance from top of opening to throat F 8" Smoke chamber edge of shelf G Rear wall - thickness 6" Front and sidewall - thickness 8" Chimney H Four No. 4 full length bars for chimney up to 40" wide. Vertical reinforcing 2 Add two No. 4 bars for each additional 40" or fraction of width or each additional flue. Horizontal reinforcing 2 J 1/4" ties at 18" and two ties at each bend in vertical steel. Bond beams K No specified requirements. Fireplace lintel L Noncombustible material. Walls with flue lining M Brick with grout around lining or 1/2" airspace 4" min. from flue lining to outside face of chimney. Walls with unlined flue N 8" solid masonry. Distances between adjacent flues See Section Effective flue area (based on area P See Section of fireplace opening) Clearances R Wood frame See Sections and Combustible material See Section Above roof 2' at 10' Anchorage 2 S Strap 3/16" x 1" Number 2 Embedment into chimney 12" hooked around outer bar w/6" ext. Fasten to 4 joists Bolts wo 1/2" diameter. Footing hickness 12" min. Width 6" each side of fireplace wall. For SI: 1 inch = 25.4 mm, 1 foot = mm. 1 2 he letters refer to Figure Not required in Seismic Zone 0, 1 or 2. 2