| 9.21.4. |
Masonry and Concrete Chimney Construction |
| 9.21.4.1. |
Unit Masonry
- Unit masonry shall conform to Section 9.20.
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| 9.21.4.2. |
Concrete
- Concrete shall conform to Section 9.3.
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| 9.21.4.3. |
Footings
- Footings for masonry chimneys and concrete chimneys shall conform to Section 9.15.
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| 9.21.4.4. |
Height of Chimney Flues
- A chimney flue shall extend not less than
- 900 mm above the highest point at which the chimney comes in contact with the roof, and
- 600 mm above the highest roof surface or structure within 3 m of the chimney. (See Note A-9.21.4.4.(1).)
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| 9.21.4.5. |
Lateral Stability
- Except as provided in Sentence (2), chimneys shall be braced in accordance with Subsection 4.3.2. to provide lateral stability under wind loads.
- A chimney need not be laterally braced provided
- no horizontal outside dimension is less than 400 mm, and
- the chimney extends not more than 3.6 m above a roof or the masonry wall of which it forms a part. (See Note A-9.21.4.5.(2).)
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| 9.21.4.6. |
Chimney Caps
- The top of a chimney shall have a waterproof cap of reinforced concrete, masonry or metal.
- The cap required in Sentence (1) shall slope from the lining and be provided with a drip not less than 25 mm from the chimney wall.
- Cast-in-place concrete caps shall be separated from the chimney liner by a bond break and be sealed at that location.
- Jointed precast concrete or masonry chimney caps shall have flashing installed beneath the cap extending from the liner to the drip edge.
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| 9.21.4.7. |
Cleanout
- A cleanout opening with a metal frame and a tight-fitting metal door shall be installed near the base of the chimney flue.
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| 9.21.4.8. |
Wall Thickness
- The walls of a masonry chimney shall be built of solid masonry units not less than 75 mm thick.
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| 9.21.4.9. |
Separation of Flue Liners
- Flue liners in the same chimney shall be separated by not less than 75 mm of masonry or concrete exclusive of liners where clay liners are used, or 90 mm of firebrick where firebrick liners are used.
- Flue liners referred to in Sentence (1) shall be installed to prevent significant lateral movement.
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| 9.21.4.10. |
Flashing
- 1) Junctions with adjacent materials shall be adequately flashed to shed water.
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