Maximum height of vertical waste stack

[redeyedfly]

Where in the plumbing codes are waste stacks limited in height? A plumber was explaining why they used cast iron for the first X feet and then switched to PVC above to meet the limitation on PVC stack height but I can't find it. There was also something about 45deg offsets at some interval for roof drains to slow down the water.

Any help pointing me to the relevant code sections is appreciated. Thanks

 

[Joe.B]

I thought this was just a CA thing, but maybe other states have adopted similar?

2022 California Plumbing Code

701.2 Drainage Piping. Materials for drainage piping shall be in accordance with one of the referenced standards in Table 701.2 except that:

2. ABS and PVC DWV piping installations shall be installed in accordance with applicable standards referenced in Table 701.2 and he firestop protection requirements in the California Building Code. Except for individual single-family dwelling units, materials exposed within ducts or plenums shall have a flame-spread index of not more than 25 and a smoke-developed index of not more than 50, where tested in accordance with ASTM E84 or UL 723. Plastic piping installed in plenums shall be tested in accordance with all requirements of ASTM E84 or UL 723. Mounting methods, supports and sample sizes of materials for testing that are not specified in ASTM E84 or UL 723 shall be prohibited.
1. [HCD 1 & HCD 2] ABS and PVC installations are limited to not more than two stories of areas of residential accommodation.

 

[Joe.B]

The explanation I heard was that as the waste is traveling down the vertical stacks, it gets loud as it picks up speed. The cast iron is quiet.

 

[Paul Sweet]

I think there used to be a requirement to offset vertical stacks every 10 stories or so, but IPC 711 only says what to do if there is an offset and the building is 5 or more stories. I don't see where it says an offset is required in the 2021 IPC.

 

[ICE]

I had to go back to 2014 in order to find a code that I can copy and paste but the info is basically the same as today. I diod not find a restriction on height.

2013 CPC
907.1 Drainage Stack. Each drainage stack that extends 10 or more stories above the building drain or other horizontal drain, shall be served by a parallel vent stack, which shall extend undiminished in size from its upper terminal and connect to the drainage stack at or immediately below the lowest fixture drain. Each such vent stack shall also be connected to the drainage stack at each fifth floor, counting down from the uppermost fixture drain, by means of a yoke vent, the size of which shall be not less in diameter than either the drainage or the vent stack, whichever is smaller.