The Ontario Building Code | Fireplace Chimneys

9.21.2.5. fireplace Chimneys

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

Table 9.21.2.5.A.
Diameter of Round Flues for fireplace Chimneys

Forming Part of Sentence 9.21.2.5.(1)

Item

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.

1.

Up to 0.150

110

170

100

160

90

150

90

150

2.

0.151 to 0.250

150

210

130

190

130

190

120

180

3.

0.251 to 0.350

180

240

160

220

150

210

140

200

4.

0.351 to 0.500

220

280

200

260

190

250

170

230

5.

0.501 to 0.650

260

320

230

290

220

280

200

260

6.

0.651 to 0.800

290

350

260

320

240

300

220

280

7.

0.801 to 1.00

330

390

290

350

270

330

250

310

8.

1.01 to 1.20

360

420

320

380

300

360

270

330

9.

1.21 to 1.40

390

450

350

410

330

390

300

360

10.

1.41 to 1.60

420

480

380

440

350

410

320

380

11.

1.61 to 1.80

400

460

370

430

340

400

12.

1.81 to 2.00

400

460

360

420

13.

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)

Item

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.

1.

Up to 0.150

200 × 200

200 × 200

100 × 200

100 × 200

100 × 200

100 × 200

100 × 200

100 × 200

2.

0.151 to 0.250

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

200 × 200

3.

0.251 to 0.350

200 × 300

200 × 300

200 × 200

200 × 300

200 × 200

200 × 200

200 × 200

200 × 200

4.

0.351 to 0.500

300 × 300

300 × 300

200 × 300

200 × 300

200 × 300

200 × 300

200 × 200

200 × 300

5.

0.501 to 0.650

300 × 300

300 × 400

300 × 300

300 × 300

300 × 300

300 × 300

200 × 300

200 × 300

6.

0.651 to 0.800

300 × 400

300 × 400

300 × 300

300 × 400

300 × 300

300 × 300

300 × 300

300 × 300

7.

0.801 to 1.00

400 × 400

400 × 400

300 × 400

300 × 400

300 × 400

300 × 400

300 × 300

300 × 300

8.

1.01 to 1.20

400 × 400

400 × 400

400 × 400

400 × 400

300 × 400

300 × 400

300 × 400

300 × 400

9.

1.21 to 1.40

400 × 400

400 × 400

400 × 400

400 × 400

300 × 400

300 × 400

10

1.41 to 1.60

400 × 400

400 × 400

400 × 400

400 × 400

11.

1.61 to 1.80

400 × 400

400 × 400

12.

1.81 to 2.00

400 × 400

400 × 400