Vents for floor drains and similar situations

Chuck_17

I am having a midlife crises concerning venting and circuit venting floor drains.

I have always assumed: If the floor drain is in the middle of a room the vent can be connected (at a 45 deg or more above center) and then piped horizontally (below the floor) over to the wall where it can go up vertically. Same with circuit vent for multiple floor drains.

It has been recently pointed out that the dry vent needs to go up 6” above flood level which would put it coming up in the middle of the floor.

Any helpful input?

I can sketch this if it would be helpful.

mikedo

what code book are you working out of its legal in some code books

Lyle {pheloa} Carter

The 6 Inches above flood level is the height for connecting into another vent. So, trap vent does not become a drain when the drain becomes plugged.

hot_rod

in big open rooms , brew pubs, warehouses, etc you can have a combination waste/ vent system designed by an engineer

The one system I did had 3” drain lines reduces to 2” traps so there was air space in the piping for venting

It was in a brew pub with no inside walks to vent up

Intplm.

@Chuck_17 The above drawing that @hot_rod posts above is an excellent example of traps vented as floor drains.

I'm guessing you are thinking about the term "six inches above flood level rim." That requirement can be established when the trench is dug deep enough to accommodate that measurement. What does the code book say in your area?

Chuck_17

NY State which is basically the 2019 IPC.

The drawing above looks like a typical circuit vented.

The code for Comb Waste and Vent says vent vertically 6" above flood level before horizonal offset. (flood level for floor drains is the floor I assume) Does that mean no horizonatl offset to the wall, or a horizontal offset that other fixture vents may be connected to?

Side question - How do you vent a bank of floor mount water closets?

Chuck_17

BTW when ever I see example schematics of circuit venting, the vent always goes straight up like there is a wall there. There is never a wall right there.

Alan (California Radiant) Forbes

Side question - How do you vent a bank of floor mount water closets?

Conventional venting on toilets since there’s usually a wall close by. Each one gets its own vent and can be combined once you’re 6” above the flood rim of the fixture.

Intplm.

Here is one example of how to vent floor-mounted water closets.

Intplm.

Sorry about the blurry pic. but you get the idea.

hot_rod

Often in public restrooms, toilets that are back to back can share a single vent.

There are other "engineered" options. A SoVent is a single vent system that serves multiple fixtures.

Mad Dog_2

Its where those vents connect in to a branch vent, vent stack or stack vent. The "tie in" needs to be 6" Above Flood Level Rim of the tallest fixtures in that room. As long as you maintain minimum pitch back toward the drain it serves, and respect the sizing charts, you can run quite far before coming up in to a wall or chase. Mad Dog

Mad Dog_2

Back to back fixture venting is called Common or unit venting. Mad Dog

Mad Dog_2

Chuck, they do that to keep sketches very simple…Unfortunately, we do the real learnin' on the job and from our elder statement. Mad Dog

Mad Dog_2

Chuck...all codes that I am familiar with no longer require that a vent take off be at a 45 degree or great which is ideal. As long as the connection is skewed up greater than 95 degrees from the center of the drain, it is acceptable. Mad Dog

Mad Dog_2

hot_rod

It may vary from code to code

With a 3” toilet, the vent can be as far as 12’ from the fixture.

2” horizontal up to 40’, or more if you increase the pipe size

Mad Dog_2

Distances have gotten much more lenient. NYC up until about 12 yrs ago was each trap requires it's own vent and within in 2 feet...period. now it's 4 feet & they do allow some Wet Venting. Mad Dog