Vent for Island Sink? Rough Plumbing


Old 11-07-02, 09:15 AM
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Vent for Island Sink? Rough Plumbing

Ok.. the plumber I hired installed the drain line for the sink then he ran another line afterwards that will run to the second story to a vent. The inspector said that was no good so he failed me. he said the Vent had to come in front of the drain line. So we changed it. The plumber said he had never done it that way and he has been a plumber for many many years. Is the inspector giving me a hard time? Or is this the correct way to run the vent? Seems like to me. He is giving me a hard time. I want my plumbing right though. But I do hate paying reinspection fees!
Old 11-07-02, 11:11 AM
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See replies below

Last edited by Plumber2000; 11-11-02 at 03:45 PM.
Old 11-09-02, 10:25 AM
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There is a good picture of a loop vent at:

May be good to compare/contrast with plumber 2000 picture

Good Luck
Old 11-09-02, 10:57 AM
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UPC Code 97


Special Venting for Island Fixtures

Traps for island sinks and similar equipment shall be roughed in above the floor and may be vented by extending the vent as high as possible, but not less than the drainboard height and then returning it downward and connecting it to the horizontal sink drain immediately downstream from the vertical fixture drain.

The return vent shall be connected to the horizontal drain through a wye-branch fitting and shall, in addition, be provided with a foot vent taken off the vertical fixture vent by means of a wye-branch immediately below the floor and extending to the nearest partition and then through the roof to the open air or may be connected to other vents at a point not less than six (6) inches (152 mm) above the flood level rim of the fixtures served.

Drainage fittings shall be used on all parts of the vent below the floor level and a minimum slope of one-quarter (1/4) inch per
foot (20.9 mm/m) back to the drain shall be maintained.

The return bend used under the drainboard shall be a one (1) piece fitting or an assembly of a forty-five (45) degree (0.79 rad), a ninety (90) degree (1.6 rad) and a forty-five (45) degree (0.79
rad) elbow in the order named.

Pipe sizing shall be as elsewhere required in this Code.

The island sink drain, upstream of the returned vent, shall serve no other fixtures.

An accessible cleanout shall be installed in the vertical portion of the foot vent.

End of Code

Last edited by Plumber2000; 11-11-02 at 03:47 PM.
Old 11-10-02, 09:16 PM
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Well, while all this loop-venting stuff looks real neat on paper, I can't believe there are inspectors out there still enforcing that junk... I would say he is giving you a hard time, even if it IS the code... His job is to make sure the sink is functional and he has to power to bend the rules if in his opinion the system is still safe and functional... Here in Georgia, we use the Standard Plumbing Code, but it does not mention the foot vent, and in fact we are allowed to used air-admittance valves in the case of a bar sink... In fact, while code is sketchy on island fixtures, we are still allowed to trap an island fixture under the floor if it is impractical to do anything else... I guess we have it easy here... oh well...

The easiest thing for you to do is to just do as the inspector says... here in Atlanta, I dont know if they charge for coming out a second time, as I dont think I have ever been failed... but I dont think they do...

If you want to just keep this can of worms open, then INSIST that he show you in the codebook where Air-admittance valves arent allowed and where your existing vent system is not code, .... he has an obligation to show you IN THE CODEBOOK why he failed the job.... If he gives any trouble call his supervisor and ask him what has to be done to get the job passed.... he can override the Barney Fifes of the world that have the authority chip on their shoulder....
Old 11-11-02, 12:06 AM
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here is a good illistration of how to do an island vent according to the UPC:

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