Need Feedback on DWV Plan for Addition

[ebammann]

Hi everyone,
I'm adding a second story on my house; new master bath, second bath, and laundry on the new 2nd floor. Here are a couple simple sketches of my new plumbing plan. I'm planning on draining and venting the fixtures on the back wall and the side wall separately.

The first picture is for the shower and tub on the second floor which will be above the kitchen sink on the first floor. I'm planning on using 2" pipe for the drain lines and 1 1/2" for the vent lines. Does this look reasonable? Is there a better way to do this?

The second picture shows the fixtures along the side wall. I was planning to use 1 1/2" pipe for all the vents except for the main stack where I was going to use 3" for the vent. I tried to annotate the picture with the size of pipes. Is 1 1/2" ok for all the vent pipes? Is 3" overkill for the main stack vent?

Any other problems that anyone sees with this plan?

I'm in Los Angeles County.

Thanks so much for any help anyone can give.
Elizabeth

 

[hj]

dwv

Using a literal interpretation of your drawing, the right hand toilet is not vented and neither is the right hand lavatory of the side by side in the left hand room.

 

[Sponsor]

 

[ebammann]

hj,
Thanks for the response.

The right hand toilet is 3 ft from the main stack, and the right hand lavatory is 3.5 ft from the stack. Since these were within the critical distance (10 ft for a 3" vent, or 6 ft for a 2" vent), I thought that I would not need a separate vent for those two. Am I wrong here?

Thanks for your help.

 

[NHmaster]

Rule of thumb, every time you go down with drainage you need to go up with a vent, regardless of how far it is.

 

[hj]

distances

Those measurements only apply if the fixture is the only one on the line, and the drain does not drop downwards before the vent. The first applies to the toilet, the second to the lavatory. The 1 1/2" vent to the right of that toilet is strictly cosmetic and performs absolutely no function.

 

[RT]

Those measurements only apply if the fixture is the only one on the line, and the drain does not drop downwards before the vent. The first applies to the toilet, the second to the lavatory. The 1 1/2" vent to the right of that toilet is strictly cosmetic and performs absolutely no function.

hi HJ - sorry if I'm being a bit clueless here - I'm reading some of these threads to better understand venting requirements in my (small) project.

when you say "the first applies to the toilet" are you referring to the first rule (only 1 fixture on the line) or the first measurement as quoted by the OP (10 ft for a 3" vent)?

thanks for any sanity checks

 

[Terry]

I can't tell how your fixtures are being vented.
Like NHmaster mentioned, the pipe goes from ground to air (through roof)

 

[hj]

rules

The first rule, i.e., 10' from the vent, (and here it would be 6'), applies ONLy if the fixture is the only one on the line, and usually the vent is downstream of the fixture.

 

[ebammann]

Ok. I think I get it now.
I will need to add a vent above the toilet and lavatory where I don't have them now.

hj, the 1 1/2" vent to the right of the toilet that you mentioned is the vent for the shower, so I do believe it's performing a purpose, unless I'm really missing something.

On that wall, I believe I have 16 fixture units that will be vented thru the main stack thru the roof. What size should this pipe be? Would 2 1/2" be ok, or would I need 3"?

Thanks so much for all your help.