View Full Version : Stall Vent Question
http://www.imagestation.com/picture/sraid202/p5d1e5bc72c9325f79808a1dd2f8c7cf3/efea2a85.jpg
I found this example on one way to vent a shower stall drain.
I've read that a '...vent is supposed to rise vertically not less than 6" above the flood level rim of the fixture served before offsetting horizontally...'. In the example above, I would assume the flood level rim of the stall is the top of the curb (not shown in pic) yet the vent is running horizontally well below the curb-top. Could someone explain this seeming discrepancy?
Terry
03-08-2006, 10:50 AM
Most plumbing inspectors would turn down the plumbing on that drawing.
Below the flood level, every fitting should be a waste fitting.
The tee should be replaced by a wye, and the 90 el's should be at least a med 90.
We use 45's and long 90's when going from horizontal up to vertical.
If it were me, I would have used a wye and a 45, angled toward the wall, and a long 90 going up the wall.
I haven't bought a "vent" 90 in twenty years.
Most plumbing inspectors would turn down the plumbing on that drawing.
Below the flood level, every fitting should be a waste fitting.
The tee should be replaced by a wye, and the 90 el's should be at least a med 90.
We use 45's and long 90's when going from horizontal up to vertical.
If it were me, I would have used a wye and a 45, angled toward the wall, and a long 90 going up the wall...
Thank you Terry.
So if the fittings were as you describe--it would pass inspection?
I still don't understand (based on my original question) why this design is acceptible since the vent in the pic is not 6" above the floodline of the fixture? Can anyone explain this? Inquiring minds... :confused:
dubldare
03-08-2006, 05:18 PM
I was told something when I was an apprentice.
"Go to your vent first."
It took a few years to understand that phrase. So simple, but it is so very relevant to proper DWV piping.
Most people get to thinking, "I'm gonna run this waste line straight toward the drain/stack and bring my vent to it." That's how you get an installation like the one shown here.
The drawings below show the same install, but routing to the vent first. The santee/st 90 illustration requires a bit of depth, but even venting with a san tee on it's back or rolling a wye up towards the vent is another option. The key in both drawings is to go to the vent first, not 'bring the vent to your pipe'.
Flat vents in most all cases can be avoided. I tend to err on the side of trap protection. You are limited in offsets/length between a trap and it's vent, not in the piping downstream of the vent.
http://www.imagestation.com/picture/sraid202/p5d1e5bc72c9325f79808a1dd2f8c7cf3/efea2a85.jpg
I found this example on one way to vent a shower stall drain.
I've read that a '...vent is supposed to rise vertically not less than 6" above the flood level rim of the fixture served before offsetting horizontally...'. In the example above, I would assume the flood level rim of the stall is the top of the curb (not shown in pic) yet the vent is running horizontally well below the curb-top. Could someone explain this seeming discrepancy?
I have always known this as flat venting and no inspector would pass it.
The city I live in won't even let you come off a vent T with a 45. It has to rise straight until it is above the flood rim
I have always known this as flat venting and no inspector would pass it.
The city I live in won't even let you come off a vent T with a 45. It has to rise straight until it is above the flood rim
Thanks dubldare & Cass.