Code Changes for "Next Time"
3/15/07

Code change proposals for 2007-8 cycle are due August 20, 2007. See Schedule (PDF)

Notes:

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

Shrouds

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 masonry solid 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.

R1003.4 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.

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 or equivalent.

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.

R1003.9.1 2 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.

Reason: To be consistent and proportional to the 8" firebox walls and 4" chimneys wall requirements.

- 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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