Understanding International Plumbing Code: Drainage Pipe Sizing

International Plumbing Code Chapter 7 is all about sanitary drainage systems. This video presentation covers IPC sections 709 to 710, which gives specific information about drainage pipe sizing. This includes an explanation of the tables used to size DWV pipe, as well as multiple examples of how to size drainage pipe.
This video is based on the 2021 International Plumbing Code, so chapter 7 might look a little different than previous or later versions of the code. Generally, the code requirements do not change much from one edition to the next.
To purchase a copy of Plumber-Tom's study companion published by Upstryve, click on this link: www.amazon.com/Journeyman-Plu...

[@seanmarron8423]

As a master plumber in Ohio & West Virginia, I am impressed by your presentations. Wish I had access to videos like these as a young plumber. You do an excellent job explaining in simple terms some very difficult code and meaning. Keep up the great work!

[@plumber-tom9470]

Thanks!

[@DontLookBehindYou1]

This channel is underrated...i hope it keeps on with this info ... It's great to have an ipc specific channel.

[@plumber-tom9470]

Thanks for watching.

[@zunairashahbaz7881]

Thank you so much for explaining these.

[@plumber-tom9470]

You're very welcome!

[@erniebrown5836]

Thanks Tom. Cleared up alot for me

[@plumber-tom9470]

Glad it helped

[@nickschneider6911]

Awesome video!

[@plumber-tom9470]

Thanks!

[@KurtDavis-y8c]

When determining pipe size on building drain with 48.5 DFUs i see it should be 4”. But if i move past two branch lines that have 9.5 DFUs do i move to a 3”? Also if no slope is given what slop size should i use?

[@abdulalsayid9014]

❤

[@plumber-tom9470]

Thanks. Hope it was helpful.

[@billsnyder6945]

Thanks for the video, very informative. I am remodeling a bathroom changing a tub to a shower. Most of the drains for pans etc are 2”, but existing line is 1 1/2”. Since the rules on showerheads are 2 gpm, do I need to change it to 2”?

[@plumber-tom9470]

No. 1 1/2” should be ok for a shower.

[@billsnyder6945]

@@plumber-tom9470 thanks, I think some local codes require 2”, but I just went for plan review and mine doesn’t

[@plumber-tom9470]

Sounds good. @@billsnyder6945

[@anabellasimbana6706]

HI Tom Thanks for your videos I learn many thing. Please this number I can found in a table 1 DFU = 7.48 GPM ?

[@plumber-tom9470]

That is not on the tables. But historically it is the basis for the tables

[@matthewhalford2650]

So let’s say I have two bathroom units on a second story draining down to the first floor on a 3” pipe, then that 3” runs to the main sewage line under the slab. Can I tie 7 more DFUs into the 3”?

[@plumber-tom9470]

On the tables in chapter 7 you will find then number of drainage fixture units for pipe sizes. It sounds like you should be fine if you have two bathroom groups and the other 7 DFUs. A bathroom group is 5 DFUs. And a 3" horizontal branch can handle 20 DFU. So it sounds like you have 17 DFU total and you should be fine.

[@waelKy]

1 DFU = 7.48 GPM , where that come from ? i think it's a huge number

[@plumber-tom9470]

1 cubic foot of water = 7.48 gallons DFUs were originally based on the movement of a cubic foot of water.