Below are two wet vent diagrams. Code says the lavatories are okay but when I substitute the bidet, I'm told it's wrong. Why?

This is a follow up to [www.plbg.com] where bernabeu says "the toilet would be wet vented by the bidet - a no-no"






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Because the way you have it drawn, the bidet is an "S" trap.

Sorry, I didn't mean for my lousy sketchup drawing to be interpreted as an S-Trap. (The lav's also are 1-1/4" P-Traps.) The bidet has a 1-1/4" P-Trap. The drawing has been updated.



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substitute the bidet for the tub and add another lav. this is the way it should be.
vent for toilet is downstream, it doesn't come from behind it.
tub or bidet enters straight thru the "Y" and the branch of that "Y" as well as the toilet vent "Y" are rolled up.

But my plumber and bernabeu says this is wrong (see bernabeu [www.plbg.com]). Just to make sure, I revised your drawing. Is it still correct?

Either I'm not getting it or plumbers have differing opinions.

every time you flush the toilet some of the water and waste splashes back into the bidet drain.
why don't you just tie the bidet drain into where i have drawn a tub drain? no vent is needed as it is wet vented thru the double lav.
plumbers do have varying opinions about how to treat different circumstances. i prefer wet venting because the fixture being wet vented washes the vent as it drains. if the wet vent clogs you will know immediately as the fixture will not drain. a wet vent pipe must be increase by one pipe diameter to allow for proper draining and a free flow of air simultaneously.

to clarify my position:


best/good practice many times exceeds minimum code requirement


best/good practice = individual fixture (dry) venting


as opposed to code MINIMUM which often permits wet venting


if your walls are open, for a couple extra fittings, you CAN individually vent each fixture

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

packy - thanks for clarifying the toilet flush problem.
bernabeu - thanks for the best practice note.

My problem is I bought all this stuff because the inspector gave me a pre-approval nod. Then I found an MP who looked over the situation and raised the flags. Now I'm between the proverbial...

The bath is 8' x 5' plus a 3 x 3 shower so it's a small space.

What if I replaced the 3x3x2 wye with a 3x3x3 then immediately vented as the first thing out of the wye. Would this pass for a circuit vent? Then I could reduce down to 2" for the bidet and still vent it separately.

Here's a mock up although down and around a corner to the stack for that sanitary tee.




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good practice:





toilet is wet vented:




let your licensed bonded insured plumber decide - have HIM get the permit on your behalf - YOU call for the final 'roughing' inspection BEFORE payment in full

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

The problem with the second revised diagram is that the bidet is not washed by an upstream fixture. The vent starts out horizontal before going vertical and as such, must be washed. To make it legit, bring the bidet drain into a sweep and take off a vertical vent between the bidet and the toilet.

The first diagram is code because the lavs are washing the horizontal portion of the vent.



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code is the MINIMUM requirement for human occupancy


the OP will have open walls


why not go for best practice if only a few $$$ more ?


simply 'loop' the vent from the farthest fixture and tie in each fixture - a few extra fittings, but actually simpler

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



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geesh bernabeu, i don't think you understand the difference between exceeding minimum code and feeding one's family. when a plumbing contractor is in business and does competetive bidding he/she has two options. bid according to minimum code or apply for welfare.

The lavatory drain "washes" the flat vent, but there is nothing to wash the bidet's flat vent and keep it clean.



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There are cases, such as this one, where "minimum code" is ALL THAT IS NECESSARY, because that is adequate to protect life and limb. In fact, less than minimum is often still adequate because of the laws of physics.

the OP has a vendor

the OP has a permit

the OP has open walls (or will have)

the OP is free to pay a few bucks more for 'best practice'

best practice would, IMO, involve more material but less labor (that is not the point)


? why are we debating this issue ?

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Quote

.....when a plumbing contractor is in business and does competetive bidding he/she has two options. bid according to minimum code or apply for welfare.....

third option:

bid as per SPECIFICATIONS, while also ensuring minimum code compliance

eg. customer requires individual fixture venting as per good/best practice

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

quote; customer requires individual fixture venting as per good/best practice

Yes, IF you can do it for the same price as the competition who are NOT doing it that way.

but the customer is free to SPECIFY that individual vents are JOB REQUIRED as the BASIS for any bids


come on, y'all, we DO KNOW the difference between PROPOSALS and BIDS

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

to repeat:

Quote

let your licensed bonded insured plumber decide - have HIM get the permit on your behalf - YOU call for the final 'roughing' inspection BEFORE payment in full

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

You are implying that ONLY YOUR way will get a final inspection while the other "code approved" ways because they are to the "minimum code" will not be? Inspections do not work that way, and customers want the lowest priced BID they can get.

You miss my point.

Simply getting proposals to do a specific task (install x,y,z) is totally different than making a set of specifications for said installation and THEN getting bids for the EXACT SAME WORK.


Give me a price to install x,y,z leaves the issue open to the contractor's method.

Give me a price to install x,y,z including individual fixture vents would be more SPECIFIC (as in specifications).

Either way the work must comply with code.


IMO:

Get a few detailed proposals as to how and materials including price.

Pick and/or modify a method and put THAT EXACT THING out for bids.

else you are comparing the cost of apples to oranges


PROPOSAL DOES NOT EQUAL BID

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

MOst of the time all I get is a roll of blueprints and am asked to give them a price for the system.

EXACTLY

you are bidding on a set of actual specifications

others are bidding on the SAME specs



the builder may, or may not, have specified individual fixture vents


you are not making a proposal, you are making a bid



(obvious to you and me, not to the OP)

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638