Shower drain - too much slope ?

[frank19991999]

Upgraded the drain to 2", I understand the min slope is 1/4" per foot, is there a max ? Read somewhere about a max of 3" per foot, not sure if is reliable information.

Currently the drain drops 4" in about 38", venting is done at 9" from the trap weir.

Thanks much,

 

[Reach4]

Upgraded the drain to 2", I understand the min slope is 1/4" per foot, is there a max ? Read somewhere about a max of 3" per foot, not sure if is reliable information.

Currently the drain drops 4" in about 38", venting is done at 9" from the trap weir.

Between the trap and the vent, that section is called the trap arm. There is a maximum for that.
If you are saying that your 2 inch trap arm drops 0.95 inches before the vent, it will work well. I don't know if that is a technical violation or not. I am not a plumber.

After the vent, the path is called a drain or a wet vent. No max for a drain, or a wet vent. The min for a drain is 1/4 per foot for a 2 inch drain, and I don't know what the minimum is for a wet vent.

 

[Sponsor]

 

[frank19991999]

Between the trap and the vent, that section is called the trap arm. There is a maximum for that.
If you are saying that your 2 inch trap arm drops 0.95 inches before the vent, it will work well. I don't know if that is a technical violation or not. I am not a plumber.

After the vent, the path is called a drain or a wet vent. No max for a drain, or a wet vent. The min for a drain is 1/4 per foot for a 2 inch drain, and I don't know what the minimum is for a wet vent.

Thanks for your reply, was asking about the maximum slope.

 

[Reach4]

Thanks for your reply, was asking about the maximum slope.

Maximum slope of what? Drain, or trap arm?

 

[frank19991999]

v

 

[frank19991999]

The pipe ends in a 3x3x2 wye.
Here is a picture:

And here is the reference to a maximum slope of 3" per foot: http://www.doityourself.com/stry/drain-pipe-slope-calculation

 

[Terry]

3" per foot is wrong. A handy man site huh?
Cut the line back and get the proper 1/4" per foot grade on it. If you need fittings, then that is what it takes.
Normally inspectors don't like to see flat venting unless it's washed by a lav. That you you can snake the line from the lav if needed in the future.
Why isn't the vent to the left? Normally that's where I would expect to see a vertical vent with a santee up into a wall.

 

[frank19991999]

3" per foot is wrong. A handy man site huh?
Cut the line back and get the proper 1/4" per foot grade on it. If you need fittings, then that is what it takes.
Normally inspectors don't like to see flat venting unless it's washed by a lav. That you you can snake the line from the lav if needed in the future.
Why isn't the vent to the left? Normally that's where I would expect to see a vertical vent with a santee up into a wall.

The trap is almost resting on the laundry room ceiling, cannot drop it anymore. The other end of the 2" pipe is tied into a 3" and is 1" away from a sistered joist

The original vent was thru the right I just used the same one. From the wye I go slightly up and towards the trap with a 90 fitting, then the 2" pipe. At this point I am not sure how would I make it right unless I add at least 2 more 90 fittings at the "wye side of the pipe" , if you can pls make some suggestions...

From what I read this situation might lead to 2 issues: siphoning and solids left behind. It seems to me that the plumbing masters dont quite agree on the solids left behind theory . Still reading about siphoning...
Here are 2 more pictures.

Thanks for helping

 

[Terry]

You start at the trap, as that has a small range of where it can be. You then work backwards to the 3" line at the proper grade, even if you add some fittings. those can be 22's or 45's.
On the vertical section of the vent, you can 90 over at six inches above the flood level of the highest fixture served. Normally we do that at 42" as the highest countertop is 36".
45's are considered vertical. I sometimes just use two 45's to offset if I'm below 42".
With venting, UPC wants it within five feet on a 2" line if it's run at a 2% grade to break the siphon. I'm not worried about solids being left behind on a shower, I do worry about venting.

 

[frank19991999]

You start at the trap, as that has a small range of where it can be. You then work backwards to the 3" line at the proper grade, even if you add some fittings. those can be 22's or 45's.
On the vertical section of the vent, you can 90 over at six inches above the flood level of the highest fixture served. Normally we do that at 42" as the highest countertop is 36".
45's are considered vertical. I sometimes just use two 45's to offset if I'm below 42".
With venting, UPC wants it within five feet on a 2" line if it's run at a 2% grade to break the siphon. I'm not worried about solids being left behind on a shower, I do worry about venting.

Terry, Is this the venting 90 that is wrong ?

 

[frank19991999]

Did a lot of reading today.
1. Pitch issue, I think I can fix it, if I understand correctly I am allowed 135 change of direction from the trap to the 3" pipe. Is that in the horizontal plane only? Can someone pls confirm. My plan is to go with 1/4 per foot pitch as close as possible to the 3x3x2 wye then drop vertically with some fittings. Does it sound right ?

2. Regarding the flat venting, I understand what it is and why is better to avoid it however I cant figure out how to change, I live in Toronto, Canada and I dont have an answer if is allowed.
My plan is to roll the 2x2x1.5 wye as much as I can and still have a min pitch of 1/4 per foot, if I can go with a higher pitch I will go for it. Here is a link that helped me understanding horizontal venting: http://www.plumbinghelp.ca/dwv_flat_vent/
Other suggestions are are welcomed.

Thanks much guys,

Frank