Ohio Administrative Code › Title 4101:8 - Board of Building Standards: Residential Code of Ohio › Chapter 4101:8-10 - Chimneys and Fireplaces › Section 4101:8-10-01 - Chimneys and fireplaces

Current through all regulations passed and filed through July 1, 2024
[Comment: When a reference is made
	 within this rule to a federal statutory provision, an industry consensus
	 standard, or any other technical publication, the specific date and title of
	 the publication as well as the name and address of the promulgating agency are
	 listed in rule
	 4101:8-44-01
	 of the Administrative Code. The application of the referenced standards shall
	 be limited and as prescribed in section 102.5 of rule
	 4101:8-1-01 of the
	 Administrative Code.]
SECTION
  1001
MASONRY FIREPLACES
1001.1
General.
Masonry
  fireplaces shall be constructed in accordance with this section and the
  applicable provisions of Chapters 3 and 4.
TABLE 1001.1
SUMMARY OF REQUIREMENTS
	 FOR
MASONRY FIREPLACES AND
	 CHIMNEYS
ITEM
LETTERa
REQUIREMENTS
Hearth slab thickness
A
4"
Hearth extension (each side of
				opening)
B
8" fireplace opening < 6 square
				feet.
12" fireplace opening >= 6 square
				feet.
Hearth extension (front of
				opening)
C
16" fireplace opening < 6 square
				feet.
20" fireplace opening > 6 square
				feet.
Hearth slab reinforcing
D
Reinforced to carry its own weight and
				all imposed loads.
Thickness of wall of
				firebox
E
10" solid brick or 8" where a firebrick
				lining is used. Joints in firebrick1/4"
				maximum.
Distance from top of opening to
				throat
F
8"
Smoke chamber wall thickness Unlined
				walls
G
6"
8"
Chimney Vertical
				reinforcingb
H
Four No. 4 full-length bars for chimney
				up to 40" wide. Add two No. 4 bars for each additional 40" or fraction of width
				or each additional flue.
Horizontal reinforcing
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.
Chimney walls with flue
				lining
M
Solid masonry units or hollow masonry
				units grouted solid with not less than 4-inch nominal thickness.
Distances between adjacent
				flues
-
See Section 1003.13.
Effective flue area (based on area of
				fireplace opening)
P
See Section 1003.15.
Clearances:
Combustible material
Mantel and trim
Above roof
R
See Sections 1001.11 and
				1003.18.
See Section 1001.11, Exception
				4.
3' at roofline and 2' at
				10'.
Anchorageb
Strap
Number
Embedment into chimney
Fasten to
Bolts
S
3/16" × 1"
Two 12" hooked around outer bar with 6"
				extension.
4 joists
Two1/2"
				diameter.
Footing
Thickness
Width
T
12" min.
6" each side of fireplace
				wall.
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1
	 square foot = 0.0929 m2.
Note:
This
	 table provides a summary of major requirements for the construction of masonry
	 chimneys and fireplaces. Letter references are to Figure 1001.1, which shows
	 examples of typical construction. This table does not cover all requirements,
	 nor does it cover all aspects of the indicated requirements. For the actual
	 mandatory requirements of the code, see the indicated section of
	 text.
a.
										The letters
	 refer to Figure 1001.1.
b.
										Not required
	 in Seismic Design Category A, B or C.
Click to
	 view image
For SI: 1 inch = 25.4 mm, 1 foot = 304.8
	 mm.
FIGURE 1001.1
FIREPLACE AND CHIMNEY
	 DETAILS
1001.2
Footings and foundations.
Footings for masonry fireplaces and their chimneys
  shall be constructed of concrete or solid masonry not less than 12 inches (305
  mm) thick and shall extend not less than 6 inches (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
  subjected to freezing, footings shall be not less than 12 inches (305 mm) below
  finished grade.
1001.2.1
Ash dump cleanout.
Cleanout openings located within foundation walls below
  fireboxes, where provided, shall be equipped with ferrous metal or masonry
  doors and frames constructed to remain tightly closed except when in use.
  Cleanouts shall be located to allow access so that ash removal will not create
  a hazard to combustible materials.
1001.3
Seismic
  reinforcing.
Deleted.
1001.3.1
Vertical reinforcing.
Deleted.
1001.3.2
Horizontal
  reinforcing.
Deleted.
1001.4
Seismic
  anchorage.
Deleted.
1001.5
Firebox
  walls.
Masonry fireboxes shall be
  constructed of solid masonry units, hollow masonry units grouted solid, stone
  or concrete. Where a lining of firebrick not less than 2 inches (51 mm) thick
  or other approved lining is provided, the minimum thickness of back and
  sidewalls shall each be 8 inches (203 mm) of solid masonry, including the
  lining. The width of joints between firebricks shall not be greater
  than1/4 inch ( 6.4 mm). Where a lining is not
  provided, the total minimum thickness of back and side walls shall be 10 inches
  (254 mm) of solid masonry. Firebrick shall conform to ASTM C27 or C1261 and
  shall be laid with medium-duty refractory mortar conforming to ASTM C199.
1001.5.1
Steel
  fireplace units.
Installation of steel
  fireplace units with solid masonry to form a masonry fireplace is permitted
  where installed either in accordance with the requirements of their listing or
  the requirements of this section. Steel fireplace units incorporating a steel
  firebox lining shall be constructed with steel not less
  than1/4 inch ( 6.4 mm) thick, and an air-circulating
  chamber that is ducted to the interior of the building. The firebox lining
  shall be encased with solid masonry to provide a total thickness at the back
  and sides of not less than 8 inches (203 mm), of which not less than 4 inches
  (102 mm) shall be of solid masonry or concrete. Circulating air ducts used with
  steel fireplace units shall be constructed of metal or masonry.
1001.6
Firebox dimensions.
The
  firebox of a concrete or masonry fireplace shall have a depth of not less than
  20 inches (508 mm). The throat shall be not less than 8 inches (203 mm) above
  the fireplace opening. The throat opening shall be not less than 4 inches (102
  mm) deep. The cross-sectional area of the passageway above the firebox,
  including the throat, damper and smoke chamber, shall be not less than the
  cross-sectional area of the flue.
Exception:
Rumford fireplaces shall be permitted provided that the
	 depth of the fireplace is not less than 12 inches (305 mm) and not less than
	 one-third of the width of the fireplace opening, that the throat is not less
	 than 12 inches (305 mm) above the lintel and is not less than one-twentieth the
	 cross-sectional area of the fireplace opening.
1001.7
Lintel
  and throat.
Masonry over a fireplace
  opening shall be supported by a lintel of noncombustible material. The minimum
  required bearing length on each end of the fireplace opening shall be 4 inches
  (102 mm). The fireplace throat or damper shall be located not less than 8
  inches (203 mm) above the lintel.
1001.7.1
Damper.
Masonry
  fireplaces shall be equipped with a ferrous metal damper located not less than
  8 inches (203 mm) above the top of the fireplace opening. Dampers shall be
  installed in the fireplace or the chimney venting the fireplace, and shall be
  operable from the room containing the fireplace.
1001.8
Smoke
  chamber.
Smoke chamber walls shall be
  constructed of solid masonry units, hollow masonry units grouted solid, stone
  or concrete. The total minimum thickness of front, back and side walls shall be
  8 inches (203 mm) of solid masonry. The inside surface shall be parged smooth
  with refractory mortar conforming to ASTM C199. Where a lining of firebrick not
  less than 2 inches (51 mm) thick, or a lining of vitrified clay not less
  than5/8 -inch (16 mm) thick, is provided, the total
  minimum thickness of front, back and side walls shall be 6 inches (152 mm) of
  solid masonry, including the lining. Firebrick shall conform to ASTM C1261 and
  shall be laid with medium-duty refractory mortar conforming to ASTM C199.
  Vitrified clay linings shall conform to ASTM C315.
1001.8.1
Smoke
  chamber dimensions.
The inside height of
  the smoke chamber from the fireplace throat to the beginning of the flue shall
  not be greater than the inside width of the fireplace opening. The inside
  surface of the smoke chamber shall not be inclined more than 45 degrees ( 0.79
  rad) from vertical where prefabricated smoke chamber linings are used or where
  the smoke chamber walls are rolled or sloped rather than corbeled. Where the
  inside surface of the smoke chamber is formed by corbeled masonry, the walls
  shall not be corbeled more than 30 degrees ( 0.52 rad) from
  vertical.
1001.9
Hearth and hearth extension.
Masonry fireplace hearths and hearth extensions shall
  be constructed of concrete or masonry, supported by noncombustible materials,
  and reinforced to carry their own weight and all imposed loads. Combustible
  material shall not remain against the underside of hearths and hearth
  extensions after construction.
1001.9.1
Hearth thickness.
The minimum thickness of fireplace hearths shall be 4
  inches (102 mm).
1001.9.2
Hearth extension thickness.
The minimum thickness of hearth extensions shall be 2
  inches (51 mm).
Exception:
Where the bottom of the firebox opening is raised not
	 less than 8 inches (203 mm) above the top of the hearth extension, a hearth
	 extension of not less than3/8-inch-thick (10 mm)
	 brick, concrete, stone, tile or other approved noncombustible material is
	 permitted.
1001.10
Hearth
  extension dimensions.
Hearth extensions
  shall extend not less than 16 inches (406 mm) in front of and not less than 8
  inches (203 mm) beyond each side of the fireplace opening. Where the fireplace
  opening is 6 square feet ( 0.6 m2) or larger, the
  hearth extension shall extend not less than 20 inches (508 mm) in front of and
  not less than 12 inches (305 mm) beyond each side of the fireplace
  opening.
1001.11
Fireplace clearance.
Wood beams, joists, studs and other combustible material
  shall have a clearance of not less than 2 inches (51 mm) from the front faces
  and sides of masonry fireplaces and not less than 4 inches (102 mm) from the
  back faces of masonry fireplaces. The airspace shall not be filled, except to
  provide fireblocking in accordance with Section 1001.12.
Exceptions:
1.
										Masonry fireplaces
  listed and labeled for use in contact with combustibles in accordance with UL
  127 and installed in accordance with the manufacturer's instructions are
  permitted to have combustible material in contact with their exterior
  surfaces.
2.
										Where masonry fireplaces are part of masonry or
  concrete walls, combustible materials shall not be in contact with the masonry
  or concrete walls less than 12 inches (306 mm) from the inside surface of the
  nearest firebox lining.
3.
										Exposed combustible trim and the edges of sheathing
  materials such as wood siding, flooring and gypsum board shall be permitted to
  abut the masonry fireplace sidewalls and hearth extension in accordance with
  Figure 1001.11, provided such combustible trim or sheathing is not less than 12
  inches (305 mm) from the inside surface of the nearest firebox
  lining.
4.
										Exposed combustible mantels or trim is permitted to be
  placed directly on the masonry fireplace front surrounding the fireplace
  opening providing such combustible materials are not placed within 6 inches
  (152 mm) of a fireplace opening. Combustible material within 12 inches (306 mm)
  of the fireplace opening shall not project more
  than1/8 -inch (3 mm) for each 1-inch (25 mm)
  distance from such an opening.
Click to
	 view image
For SI: 1 inch = 25.4 mm.
FIGURE 1001.11
CLEARANCE FROM
	 COMBUSTIBLES
1001.12
Fireplace fireblocking.
Fireplace fireblocking shall comply with the provisions of
  Section 602.8.