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

BuildingCode.Online

Navigate

The Ontario Building Code | Fireplace Chimneys