Code change proposals for 2007-8 cycle are due August 20, 2007. See Schedule (PDF)
There may be no residential chimneys in Seismic Design Category E which is combination of seismic zone and building use, eg hostpital.
Check mantel cleaqrances and compare with NFPA 211
R1001.8 Smoke chamber. Where a lining of firebrick at least 2 inches (51 mm) thick, or a lining of vitrified clay at least 5/8 inch (16 mm) thick, is provided, smoke chamber walls shall be constructed of solid masonry units, hollow masonry units grouted solid, stone or concrete with not less than a 4-inch (102 mm) nominal thickness.
Corbelling of masonry units shall not leave unit cores exposed to the inside of the smoke chamber. When a lining of firebrick at least 2 inches (51 mm) thick, or a lining of vitrified clay at least 5/8 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 C 27 or C 1261 and shall be laid with medium duty refractory mortar conforming to ASTMC199. Vitrified clay linings shall conform to ASTM C315. Where no lining is provided, the total minimum thickness of front, back and side walls shall be 8 inches (203 mm) of solid masonry. When the inside surface of the smoke chamber is formed by corbeled masonry, the inside surface shall be parged smooth.
Reason: To make consistent with chimney wall construction - similar heat transfer.
R1003.1 Definition. A masonry chimney is a chimney constructed of
concrete or masonrysolid masonry units, hollow masonry units grouted solid, stone or concrete, hereinafter referred to as masonry. Masonry chimneys shall be constructed, anchored, supported and reinforced as required in this chapter.
Reason: To make language same as fireplaces and smoke chambers.
R1003.3 Seismic reinforcing. Masonry or concrete chimneys shall be constructed, anchored, supported and reinforced as required in this chapter. In Seismic Design Category D0, D1 or D2 or E masonry and concrete chimneys shall be reinforced and anchored as detailed in Section R1003.3.1, R1003.3.2 and R1003.4. In Seismic Design Category A,B or C, reinforcement and seismic anchorage is not required.
R1003.3.1 Vertical reinforcing. For chimneys up to 40 inches (1016 mm) wide in Seismic Design Category D0, D1 or D2, or up to 20 inches (508mm) wide in Seismic Design Category E, four No. 4 continuous vertical bars, anchored in the foundation, shall be placed in the concrete, or between wythes of solid masonry, or within the cells of hollow unit masonry, and grouted in accordance with Section R609.1.1. Grout shall be prevented from bonding with the flue liner so that the flue liner is free to move with thermal expansion. For chimneys more than 40 inches (1016 mm) wide in Seismic Design Category D0, D1 or D2, or more than 20 inches (508mm) wide in Seismic Design Category E, two additional No. 4 vertical bars shall be installed for each additional 40 inches (1016 mm) in width in Seismic Design Category D0, D1 or D2, or 20 inches (508mm) in Seismic Design Category E, or fraction thereof.R1003.4 Seismic anchorage. Masonry and concrete chimneys and foundations in Seismic Design Category D0, D1 or D2 or E shall be anchored at each floor, ceiling or roof line more than 6 feet (1829 mm) above grade, except where constructed completely within the exterior walls. Anchorage shall conform to the requirements in Section R1003.4.1.
R1003.3.2 Horizontal reinforcing. Vertical reinforcement shall be placed enclosed within 1/4-inch (6 mm) ties, or other reinforcing of equivalent net cross-sectional area, spaced not to exceed 18 inches (457 mm) in Seismic Design Category D0, D1 or D2, or 9 inches (228 mm) in Seismic Design Category E, on center in concrete, or placed in the bed joints of unit masonry, at a minimum of every 18 inches (457 mm) in Seismic Design Category D0, D1 or D2, or 9 inches (228 mm) in Seismic Design Category E, of vertical height. Two such ties shall be installed at each bend in the vertical bars.
R1003.4.1 Anchorage. Two 3/16-inch by 1-inch (5 mm by 25 mm) straps shall be embedded a minimum of 12 inches (305 mm) into the chimney. Straps shall be hooked around the outer bars and extend 6 inches (152 mm) beyond the bend. Each strap shall be fastened to a minimum of four floor joists with two 1/2-inch (13 mm) bolts. In Seismic Design Category E the anchorage straps shall be cut and bolted back together through 2" long slots with friction bolts designed to slip at 500 pounds tension and allow 2" of movement.Reason: To include chimneys in Seismic Design Category E - See http://www.rumford.com/code/seismicrepair.html
R1003.11.1 Residential-type appliances (general). Flue lining systems shall comply with one of the following:
1. Clay flue lining complying with the requirements of ASTM C 315
Reason: What's "equivalent"? Just meet the standard.
R1003.12 Clay flue lining (installation). Clay flue liners shall be installed in accordance with ASTMC 1283 and extend from a point not less than 8 inches (203 mm) below the lowest inlet or, in the case of fireplaces, from the top of the smoke chamber to
a point above the top of the enclosing walls. The lining shall be carried up vertically, with a maximum slope no greater than 30 degrees (0.52 rad) from the vertical.
Reason: Make consistent with change in ASTM C1283.
R1003.9.1 Chimney Caps. Masonry chimneys shall have a concrete, metal or stone cap, sloped to shed water, a drip edge and caulked bond break around any flue liners in accordance with ASTMC 1283.
12 Spark arrestors.
Reason: There is no provision for a chimney cap in the code and this language will reference and be consistent with ASTM C1283.
R1003.18 Chimney clearances. Any 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). The air space shall not be filled, except to provide fire blocking in accordance with Section R1003.19.
Exceptions:Reason: To be consistent and proportional to the 8" firebox walls and 4" chimneys wall requirements.
1. 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.
2. When masonry chimneys are constructed as part of masonry or concrete walls, combustible materials shall not be in contact with the masonry or concrete wall less than
12 inches (305 mm)8 inches (203 mm) from the inside surface of the nearest flue lining.
3. Exposed combustible trim and the edges of sheathing materials, such as wood siding and flooring, shall be permitted to abut the masonry chimney side walls, in accordance with Figure R1003.18, provided such combustible trim or sheathing is a minimum of
12 inches (305 mm)8 inches (203 mm) from the inside surface of the nearest flue lining. Combustible material and trim shall not overlap the corners of the chimney by more than 1 inch (25 mm).
- R1004.3 Decorative shrouds. Decorative shrouds shall not be installed at the termination of air-cooled chimneys for factory-built fireplaces listed to UL127 except where the shrouds are listed and labeled for use with the specific factory-built fireplace system and installed in accordance with the manufacturers installation instructions.
R1005.2 Decorative shrouds. Decorative shrouds shall not be installed at the termination of factory-built chimneys except where the shrouds are listed and labeled for use with the specific factory-built chimney system and installed in accordance with the manufacturers installation instructions.
Reason: Keep Section R1004.3 but add the words "air-cooled" and "listed to UL127" as non listed decorative shrouds can interfere with the air flow of air-cooled metal chimneys listed to UL 127 for factory-built fireplaces. There is no problem, however, adding decorative shrouds to insulated factory-built chimneys listed to UL 103 that are used for masonry fireplaces, stoves, furnaces and many other appliances. Section R1005.2 is unnecessary and should be eliminated.
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