The Ontario Building Code | 90° Elbows

7.2.4.3. 90° Elbows

(1) Except as permitted in Sentences (2) and (3), 90° elbows of 4 in. size or less that have a centre-line radius that is less than the size of the pipe shall not be used to join two soil or waste pipes.

(2) 90° elbows of 4 in. size or less in sanitary drainage systems may be used,

(a) to change the direction of piping from horizontal to vertical, in the direction of flow,

(b) where a trap arm enters a wall, or

(c) to connect trap arms as permitted by Sentence 7.5.6.3.(2).

(3) A 90° elbow that is part of the pre-engineered wastewater heat recovery system is permitted to have a centre-line radius that is less than the sizeof the pipe.