CodeChronicle

OBC 2006 Division B

9.21.

Version 0 — in force 31 December 2006

In force
Verified · covered Verified against the 2006-12-31–2007-04-01 consolidation, whose range covers the query date. How to read this

Provenance

OBC 1997 · continues from 9.21. — Pro

Base · O. Reg. 350/06 · ext← current

Original — base regulation

OBC 2012 · continues as 9.21. — Pro

9.21. — Masonry and Concrete Chimneys and Flues

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9.21.1. — General

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9.21.1.1. — Application

(1) This Section applies to,

(a) rectangular masonry or concrete chimneys not more than 12 m in height serving fireplaces or serving appliances having a combined total rated heat output of 120 kW or less, and

(b) flue pipes serving solid fuel-burning appliances.

(2) Chimneys and flue pipes other than those described in Sentence (1) shall conform to Section 6.3.

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9.21.1.2. — Factory-Built Chimneys

(1) Factory-built chimneys serving solid fuel-burning appliances, and their installation, shall conform to CAN/ULC-S629-M, “650°C Factory-Built Chimneys”.

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9.21.1.3. — Chimneys, Gas Vents or Flue Pipes

(1) Except as provided in Sentence (2), chimneys (other than those described in Sentences 9.21.1.1.(1) and 9.21.1.2.(1)), gas vents and flue pipes serving gas-, oil- or solid fuel-burning appliances and associated equipment shall conform to Section 6.3.

(2) Flue pipes serving solid fuel-burning stoves, ranges and space heaters shall conform to CAN/CSA-B365, “Installation Code for Solid-Fuel Burning Appliances and Equipment”.

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9.21.1.4. — Chimney or Flue Pipe Walls

(1) The walls of any chimney or flue pipe shall be constructed to be smoke- and flame-tight.

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9.21.2. — Chimney Flues

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9.21.2.1. — Chimney Flue Limitations

(1) A chimney flue that serves a fireplace or incinerator shall not serve any other appliance.

(2) A chimney flue that serves a solid fuel-burning appliance shall not be connected to a natural gas- or propane-fired appliance.

(3) A chimney flue that serves a solid-fuel burning appliance shall not be connected to an oil-burning appliance unless the solid-fuel burning appliance is listed for such installation and the installation of both appliances meets their respective installation requirements.

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9.21.2.2. — Connections of More Than One Appliance

(1) Except as required in Article 9.21.2.1.v1, two or more fuel-burning appliances are permitted to be connected to the same chimney flue provided adequate draft is maintained for the connected appliances and the connections are made as described in Sentences (2) and (3).

(2) Where 2 or more solid fuel-burning appliances are connected to the same chimney flue, the appliances must be located on the same storey.

(3) The connection referred to in Sentence (2) for a solid fuel-burning appliance shall be made below connections for appliances burning other fuels.

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9.21.2.3. — Inclined Chimney Flues

(1) Chimney flues shall not be inclined more than 45° to the vertical.

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9.21.2.4. — Size of Chimney Flues

(1) Except for chimneys serving fireplaces, the size of a chimney flue shall conform to the requirements of the solid fuel-burning appliance installation standard referenced in Sentence 6.2.1.4.(1) and Article 9.33.1.2.

(2) Where a chimney flue serves only one solid fuel-burning appliance, the flue area shall be at least equal to that of the flue pipe connected to it.

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9.21.2.5. — Fireplace Chimneys

(1) The size of a chimney flue serving a masonry fireplace shall be within the allowable range specified in Table 9.21.2.5.A. or Table 9.21.2.5.B.

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Table 9.21.2.5.A. Diameter of Round Flues for Fireplace Chimneys Forming Part of Sentence 9.21.2.5.(1)

Column 1

Column 2

Column 3

Column 4

Column 5

Column 6

Column 7

Column 8

Column 9

Fireplace Opening, m²

Chimney Height, m

3.0 to 4.5

> 4.5 to 5.9

> 5.9 to 8.9

> 8.9 to 12

Flue diameter, mm

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Up to 0.150

110

170

100

160

90

150

90

150

0.151 to 0.250

150

210

130

190

130

190

120

180

0.251 to 0.350

180

240

160

220

150

210

140

200

0.351 to 0.500

220

280

200

260

190

250

170

230

0.501 to 0.650

260

320

230

290

220

280

200

260

0.651 to 0.800

290

350

260

320

240

300

220

280

0.801 to 1.00

330

390

290

350

270

330

250

310

1.01 to 1.20

360

420

320

380

300

360

270

330

1.21 to 1.40

390

450

350

410

330

390

300

360

1.41 to 1.60

420

480

380

440

350

410

320

380

1.61 to 1.80

400

460

370

430

340

400

1.81 to 2.00

400

460

360

420

2.01 to 2.20

380

440

Table 9.21.2.5.B. Rectangular Flue Sizes for Fireplace Chimneys Forming Part of Sentence 9.21.2.5.(1)

Column 1

Column 2

Column 3

Column 4

Column 5

Column 6

Column 7

Column 8

Column 9

Fireplace Opening, m²

Chimney Height, m

3.0 to 4.5

> 4.5 to 5.9

> 5.9 to 8.9

> 8.9 to 12

Flue Size, mm

Min.

Max.

Min.

Max.

Min.

Max.

Min.

Max.

Up to 0.150

200 × 200

200 × 200

100 × 200

100 × 200

100 × 200

100 × 200

100 × 200

100 × 200

0.151 to 0.250

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

0.251 to 0.350

200 × 300

200 × 300

200 × 200

200 × 300

200 × 200

200 × 200

200 × 200

200 × 200

0.351 to 0.500

300 × 300

300 × 300

200 × 300

200 × 300

200 × 300

200 × 300

200 × 200

200 × 300

0.501 to 0.650

300 × 300

300 × 400

300 × 300

300 × 300

300 × 300

300 × 300

200 × 300

200 × 300

0.651 to 0.800

300 × 400

300 × 400

300 × 300

300 × 400

300 × 300

300 × 300

300 × 300

300 × 300

0.801 to 1.00

400 × 400

400 × 400

300 × 400

300 × 400

300 × 400

300 × 400

300 × 300

300 × 300

1.01 to 1.20

400 × 400

400 × 400

400 × 400

400 × 400

300 × 400

300 × 400

300 × 400

300 × 400

1.21 to 1.40

400 × 400

400 × 400

400 × 400

400 × 400

300 × 400

300 × 400

1.41 to 1.60

400 × 400

400 × 400

400 × 400

400 × 400

1.61 to 1.80

400 × 400

400 × 400

1.81 to 2.00

400 × 400

400 × 400

9.21.2.6. — Oval Chimney Flues

(1) The width of an oval chimney flue shall be not less than two-thirds its breadth.

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9.21.3. — Chimney Lining

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9.21.3.1. — Lining Materials

(1) Every masonry or concrete chimney shall have a lining of clay, concrete, firebrick or metal.

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9.21.3.2. — Joints in Chimney Liners

(1) Joints of chimney liners shall be sealed to provide a barrier to the passage of flue gases and condensate into the cavity between the liner and the surrounding masonry.

(2) Joints of clay, concrete or firebrick chimney liners shall be struck flush to provide a straight, smooth, aligned chimney flue.

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9.21.3.3. — Clay Liners

(1) Clay liners shall conform to CAN/CSA-A324-M, “Clay Flue Liners”.

(2) Liners referred to in Sentence (1) shall be not less than 15.9 mm thick and shall be capable of resisting, without softening or cracking, a temperature of 1100°C.

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9.21.3.4. — Firebrick Liners

(1) Firebrick liners shall conform to ASTM C27, “Classification of Fireclay and High Alumina Refractory Brick”.

(2) Firebrick liners shall be laid with high temperature cement mortar conforming to CAN/CGSB-10.3, “Air Setting Refractory Mortar”.

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9.21.3.5. — Concrete Liners

(1) Concrete flue liners shall conform to Clause 4.2.6.4. of CAN/CSA-A405-M, “Design and Construction of Masonry Chimneys and Fireplaces”.

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9.21.3.6. — Metal Liners

(1) Metal liners shall be constructed of at least 0.3 mm thick stainless steel.

(2) Except as permitted in Sentence 9.22.10.2.(3), metal liners referred to in Sentence (1) shall only be used in chimneys serving gas- or oil-burning appliances.

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9.21.3.7. — Installation of Chimney Liners

(1) Chimney liners shall be installed when the surrounding masonry or concrete is placed.

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9.21.3.8. — Spaces Between Liners and Surrounding Masonry

(1) A space not less than 10 mm wide shall be left between a chimney liner and the surrounding masonry.

(2) The space required in Sentence (1) shall not be filled with mortar.

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9.21.3.9. — Mortar for Chimney Liners

(1) Chimney liners used in chimneys for solid fuel-burning appliances shall be laid in a full bed of,

(a) high temperature cement mortar conforming to CAN/CGSB-10.3, “Air Setting Refractory Mortar”, or

(b) mortar consisting of 1 part Portland cement to 3 parts sand by volume.

(2) Chimney liners used in chimneys for oil- or gas-burning appliances shall be laid in a full bed of mortar consisting of 1 part Portland cement to 3 parts sand by volume.

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9.21.3.10. — Extension of Chimney Liners

(1) Chimney liners shall extend from a point not less than 200 mm below the lowest flue pipe connection to a point not less than 50 mm or more than 100 mm above the chimney cap.

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9.21.4. — Masonry and Concrete Chimney Construction

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9.21.4.1. — Unit Masonry

(1) Unit masonry shall conform to Section 9.20.

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9.21.4.2. — Concrete

(1) Concrete shall conform to Section 9.3.

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9.21.4.3. — Footings

(1) Footings for masonry chimneys and concrete chimneys shall conform to the requirements in Section 9.15.

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9.21.4.4. — Height of Chimney Flues

(1) A chimney flue shall extend not less than,

(a) 900 mm above the highest point at which the chimney comes in contact with the roof, and

(b) 600 mm above the highest roof surface or structure within 3 m of the chimney.

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9.21.4.5. — Lateral Stability

(1) Except as provided in Sentence (2), chimneys shall be braced in accordance with Subsection 4.3.2. to provide stability under wind loads.

(2) A chimney need not be laterally braced provided,

(a) no horizontal outside dimension is less than 400 mm, and

(b) the chimney extends not more than 3.6 m above a roof or the masonry wall of which it forms a part.

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9.21.4.6. — Chimney Caps

(1) The top of a chimney shall have a waterproof cap of reinforced concrete, masonry or metal.

(2) 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.

(3) Cast-in-place concrete caps shall be separated from the chimney liner by a bond break and be sealed at that location.

(4) 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

(1) Except for a chimney flue constructed to serve a masonry fireplace, a cleanout opening with a metal frame and tight-fitting metal door shall be installed near the base of the chimney flue.

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9.21.4.8. — Wall Thickness

(1) The walls of a masonry chimney shall be built of solid units not less than 70 mm thick.

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9.21.4.9. — Separation of Flue Liners

(1) Flue liners in the same chimney shall be separated by not less than 70 mm of masonry or concrete exclusive of liners where clay liners are used, or 90 mm of firebrick where firebrick liners are used.

(2) 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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9.21.5. — Clearance from Combustible Construction

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9.21.5.1. — Clearance from Combustible Materials

(1) The clearance between masonry or concrete chimneys and combustible framing material shall be not less than,

(a) 50 mm for interior chimneys, and

(b) 12 mm for exterior chimneys.

(2) A clearance of not less than 150 mm shall be provided between a cleanout opening and combustible material.

(3) Combustible flooring, subflooring and ceiling finishes shall have not less than a 12 mm clearance from masonry or concrete chimneys.

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9.21.5.2. — Sealing of Spaces

(1) All spaces between masonry or concrete chimneys and combustible material shall be sealed top or bottom with noncombustible material.

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9.21.5.3. — Support of Joists or Beams

(1) Joists or beams may be supported on masonry walls that enclose chimney flues provided the combustible members are separated from the flue by a minimum of 290 mm of solid masonry.

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