DWV system planning help, NJ

[PlumbersPutty]

Our upstairs bathroom wall started to drop some tiles due to moisture getting to the drywall and since I was planning on redoing it soon anyway to get rid of the window in there, my hand has been forced.

While remodeling both bathrooms I also need to redo the DWV system as there is some galvanized pipe and the venting does not appear to be up to code.

I started to plan it out (See image here, I apologize for my terrible drawing skills in advance, the basement is a little crowded) and would greatly appreciate a check to see if I am on the right track here or am completely missing something.

 

[Cacher_Chick]

Every fixture trap must be vented within the maximum allowed distance for the size of pipe.
Your plumbing code can be found on the web for more specific guidelines.

 

[Sponsor]

 

[PlumbersPutty]

All traps and runs are 2" with none longer than 7' except for the kitchen sink which will have its own vent. It currently does not.

I have a few areas of concern:
Is the venting for the top floor toilet/tub valid?
Can I Wye the basement shower into the toilet drain as shown or must I do it some other way?
Are the 1/4 bends with the side inlets usable as dry-vents the way I have them shown?

 

[Cacher_Chick]

Vent take-offs on horizontal piping must be made with a wye or combo fitting & the vent must be vertical until it it at least 6" above the flood rim of the highest fixture served by the vent. Any fixture below the highest fixture drain on the stack must be re-vented back above that same point.
Re-read this. -- EVERY fixture's trap must have a vent.

The stack is only a vent stack above the highest drain connection.

 

[PlumbersPutty]

Every basement fixture is served by the 2 vents shown.
Kitchen sink has its own vent.
If I move the kitchen sink drain connection below the 1st floor Toilet/Tub Wye leaving only the lav above would it then be an acceptable wet vent setup?

I couldn't find anywhere in the NSPC that prohibits tee fittings from being used as dry vent connections in the middle of a horizontal run. Is there a section somewhere that lists required fitting types at these vent connections?

 

[Cacher_Chick]

The detail in your drawing does not show proper vent connections to most of the fixtures, which is why I suggested working on your drawing.
One example would be that the lower floor shower is not drawn with a proper vent. If it were plumbed that way, the trap will be siphoned every time the toilet is flushed. Another would be the laundry sink being siphoned every time the washer drains. One fixture drain cannot flow past another unless the trap is vented first.

The upper floor tub and toilet are not vented, as the use of a wye breaks the vent which would exist if there were no other drain connections above.

A vent tee is for use in dry vent piping, and is not allowed in any part of the drainage system.