Venting 4" floor drain under slab in middle of room..

[joeMack]

I am adding an addition to a building. I want a 4" trapped drain in middle of the room. My understanding is my trap needs to be within 6 feet of a vent. How does one maintain open floor space, while still venting. If, Horizontal venting needs to be 6" above highest fixture dump do I have to drop the whole design farther below grade to achieve horizontal venting below the slab, or am I missing some other options?

Thanks,
Jack of all trades, master of a couple.

 

[Sylvan]

I do not know which code your using but we were allowed to install a floor drain as long as it was with in 15 feet of a vent


Fixture traps had to be with in 2 feet of a vent and the fixture with in 2 feet of the trap

 

[Sponsor]

 

[wwhitney]

Sounds like the provisions on "Combination Waste and Vent" are intended for this condition.

Cheers, Wayne

 

[Reach4]

I am adding an addition to a building. I want a 4" trapped drain in middle of the room. My understanding is my trap needs to be within 6 feet of a vent. How does one maintain open floor space, while still venting. If, Horizontal venting needs to be 6" above highest fixture dump do I have to drop the whole design farther below grade to achieve horizontal venting below the slab, or am I missing some other options?

Thanks,
Jack of all trades, master of a couple.

Where do you see the 6 ft rule? I am not saying that does not exist. Are you saying that you will be running 4 inch pipe from the floor drain trap to the vent?

In trying to look this up, http://www.ilga.gov/commission/jcar/admincode/077/077008900D04100R.html had this surprise for me:

SECTION 890.410 FIXTURE TRAPS/CONTINUOUS WASTE

e) Drum Traps. Drum traps shall be 3 or 4 inches in diameter and provided with a fixed water seal of at least 2 inches. The trap cleanout shall be one size less than the trap diameter.​

A drum trap does not need a vent to work. I thought all codes had eliminated the drum trap, so that is why I was surprised. I think the drum trap should be permitted, at least in some cases. For example, it would be nice in some cases for a water softener drain standpipe I am not a pro, and my reading of the code doesn't hold any weight. But if you could legally put a 4 inch drum trap with a flush cover, I expect that would function well. The reason that drum traps are no longer permitted by most codes is that they are not "self cleaning".

Regarding putting a floor drain in the middle of a room, the size of the room would have a bearing.

 

[wwhitney]

The reason that drum traps are no longer permitted by most codes is that they are not "self cleaning".

FWIW, the commentary on the "Continuous Waste and Vent" also noted that it is not self cleaning, but is allowable as a solution for floor drains (and I saw a 15' foot limitation as Sylvan mentioned). So the same logic would allow a drum trap for a floor drain. If the plumbing code is logical. : - )

Cheers, Wayne

 

[joeMack]

I do not know which code your using but we were allowed to install a floor drain as long as it was with in 15 feet of a vent


Fixture traps had to be with in 2 feet of a vent and the fixture with in 2 feet of the trap

Illinois, food establishment