I want to add a bathroom upstairs and trying to figure out if I am within the maximum Drainage Fixture Units (DFU) allowed. I keep reading up on the subject and still confused so hoping someone can break it down for me in clear understandable terms.
I currently have 3 baths and I might be removing one of them, but for now let us assume I keep it. All 3 baths are on the 1st floor with a slab below. I am adding a forth bathroom upstairs. So from what I can find a bathroom group is 6 units so that is 24 units, plus washer 2 units, plus kitchen sink 2units. It says Kitchen sink with dishwasher, but it is not clear to me if the dishwasher is part of the sink or separate. But with that I have 28 units. All will be run into a 3” waste stack. Now this is where it gets confusing. I see one table that shows if I have a ¼” slope I can do 42 units and another that talks about 20 units. I think it might be tied to the way the system is branched. On the table that says 20 DFU max., it states total discharge into one branch interval.
Is each bathroom unit considered its own branch??
The 3” pipe I am tying into is under concrete, so I have no way to tell how things were branched but I do know all 3 bathrooms feed into that 3” pipe as well as the kitchen sink, dishwasher and washing machine.
I will tie into that 3” line run a stack upstairs and through the roof for venting.
I am looking for help in understand the Maximum DFU and if I am OK or have a problem.
Also a 2nd question. In order to run the 3” upstairs I will have to run it through the attic of the 1st floor and also in the floor joist above the garage. I am in Northern Florida but it can still freeze here. Is there an issue with doing that? I would have the insulation placed above the pipe in the attic and below the pipe in the garage.
I currently have 3 baths and I might be removing one of them, but for now let us assume I keep it. All 3 baths are on the 1st floor with a slab below. I am adding a forth bathroom upstairs. So from what I can find a bathroom group is 6 units so that is 24 units, plus washer 2 units, plus kitchen sink 2units. It says Kitchen sink with dishwasher, but it is not clear to me if the dishwasher is part of the sink or separate. But with that I have 28 units. All will be run into a 3” waste stack. Now this is where it gets confusing. I see one table that shows if I have a ¼” slope I can do 42 units and another that talks about 20 units. I think it might be tied to the way the system is branched. On the table that says 20 DFU max., it states total discharge into one branch interval.
Is each bathroom unit considered its own branch??
The 3” pipe I am tying into is under concrete, so I have no way to tell how things were branched but I do know all 3 bathrooms feed into that 3” pipe as well as the kitchen sink, dishwasher and washing machine.
I will tie into that 3” line run a stack upstairs and through the roof for venting.
I am looking for help in understand the Maximum DFU and if I am OK or have a problem.
Also a 2nd question. In order to run the 3” upstairs I will have to run it through the attic of the 1st floor and also in the floor joist above the garage. I am in Northern Florida but it can still freeze here. Is there an issue with doing that? I would have the insulation placed above the pipe in the attic and below the pipe in the garage.