I have a question of interpretation of Chicago building code.
I do not know if a building more than five stories or more is required horizontal stack offset.
I enclosed a portion of Chicago building code.
Thanks,
18-29-711 Offsets in Drainage Piping in Buildings of Five Stories or More.
18-29-711.1 Horizontal branch connections above or below vertical stack offsets
If a horizontal branch connects to the stack within 2 feet (610 mm) above or below a vertical stack offset, and the offset is located more than four branch intervals below the top of the stack, the offset shall be vented in accordance with Section $jumplink_md=target-id=JD_18-29-915']18-29-915.
18-29-711.1.1 Omission of vents for vertical stack offsets.
Vents for vertical offsets required by Section $jumplink_md=target-id=JD_18-29-711.1']18-29-711.1 shall not be required where the stack and its offset are sized as a building drain (see Table $jumplink_md=target-id=JD_Table18-29-710A']18-29-710A, Column 5).
18-29-711.2 Horizontal branch connections to horizontal stack offsets
When a horizontal stack offset is located more than four branch intervals below the top of the stack, a horizontal branch shall not connect within the horizontal stack offset or within 2 feet (610 mm) above or below such offset.
18-29-711.3 Horizontal stack offsets.
A stack with a horizontal offset located more than four branch intervals below the top of the stack shall be vented in accordance with Section $jumplink_md=target-id=JD_18-29-914']914 and sized as follows:
1. The portion of the stack above the offset shall be sized as for a vertical stack based on the total number of drainage fixture units above the offset.
2. The offset shall be sized in accordance with Section $jumplink_md=target-id=JD_18-29-710.1.1']18-29-710.1.1.
3. The portion of the stack below the offset shall be sized as for the offset or based on the total number of drainage fixture units on the entire stack, whichever is larger (see Table $jumplink_md=target-id=JD_Table18-29-710B']18-29-710B, Column 4).
I do not know if a building more than five stories or more is required horizontal stack offset.
I enclosed a portion of Chicago building code.
Thanks,
18-29-711 Offsets in Drainage Piping in Buildings of Five Stories or More.
18-29-711.1 Horizontal branch connections above or below vertical stack offsets
If a horizontal branch connects to the stack within 2 feet (610 mm) above or below a vertical stack offset, and the offset is located more than four branch intervals below the top of the stack, the offset shall be vented in accordance with Section $jumplink_md=target-id=JD_18-29-915']18-29-915.
18-29-711.1.1 Omission of vents for vertical stack offsets.
Vents for vertical offsets required by Section $jumplink_md=target-id=JD_18-29-711.1']18-29-711.1 shall not be required where the stack and its offset are sized as a building drain (see Table $jumplink_md=target-id=JD_Table18-29-710A']18-29-710A, Column 5).
18-29-711.2 Horizontal branch connections to horizontal stack offsets
When a horizontal stack offset is located more than four branch intervals below the top of the stack, a horizontal branch shall not connect within the horizontal stack offset or within 2 feet (610 mm) above or below such offset.
18-29-711.3 Horizontal stack offsets.
A stack with a horizontal offset located more than four branch intervals below the top of the stack shall be vented in accordance with Section $jumplink_md=target-id=JD_18-29-914']914 and sized as follows:
1. The portion of the stack above the offset shall be sized as for a vertical stack based on the total number of drainage fixture units above the offset.
2. The offset shall be sized in accordance with Section $jumplink_md=target-id=JD_18-29-710.1.1']18-29-710.1.1.
3. The portion of the stack below the offset shall be sized as for the offset or based on the total number of drainage fixture units on the entire stack, whichever is larger (see Table $jumplink_md=target-id=JD_Table18-29-710B']18-29-710B, Column 4).