Waste line drop?

[tractordude]

Is it possible to have to much drop in a waste line? I'm no plumber but 1/2 in, in 12 inches of run is the standard correct?

I finally plumbed the urinal at the shop. The urinal make's a venting sound, after the water is done. It's not a issue, just wondering if the pipe after the P trap has to much slope.
I have about a 3 inch drop in 4 feet after the P trap, then it makes a 90, then a 90 to the main waste line in the basement.

(hope that makes sense)

 

[brownbagg]

1/8 per inch, too much drop and the water will out run the turd

 

[JJThrasher]

1/8 per inch, too much drop and the water will out run the turd

That shouldn't be in issue in a urinal.

 

[pstnbly]

1/4" p/ft standard, 1/8" p/ft minimum 2% and 1% respectively. To much drop is said to allow liquids to out run the solids although there is debate about that.

 

[tractordude]

I have a commercial building with a basement. The basement houses the utility lines and that's about it.
The waste line snakes around the entry room to the basement (this is were my drop concern is), drops 90*, 90* bend, then in to the main waste line that is on the top of the basement ceiling.

(am I making any sense?)

 

[rustyjames]

If it's just for a urinal the slope shouldn't matter.

 

[Norcal]

Depends on the pipe size, 1/4" per foot w/ 3" & smaller, 1/8" per foot is permitted for 4" & larger.

 

[Marctrees]

If you spend time Googling this, you will find the "too much slope and water outruns turds" is a total false old wives tale.

Ya, I read you don't have turds in your urinal (hopefully), but the thread went to that old story.

Further - I am not SURE about this part, but |I do not think any plumbing codes have a upper limit on slope, that supports what I said above.

The only exception to the above - Depending on your water input to drain, if the slope is TOO great,AND the pipe is like "small" for that volume, it MAY **** out your trap from the velocity "pull" of the water.

Don't trust me, Google it for yourself. Marc

 

[MagKarl]

Is this new line vented?

 

[mozda]

I think you have a venting issue

There used to be something in the code about too much slope, and yes it's based on the theory that if the slope is too much the water will outrun solids (no necessarily turds).
I've looked again recently and it seems to be deleted.

Your problem is most likely venting.

 

[Mike in Ohio]

Sounds like venting to me too, how far is the urinal from the vent stack?

 

[slip knot]

2ft/sec is the industry standard and IIRC it is 1/8/ft for pipe over 4in. The 90s will create additional friction so they must be included in the factors.

pipe scour and water hammer are 2 reasons for this in addition to the " water outrunning the turds"

 

[RVDan]

Slope is irrelevant, you have a vent problem.

 

[Marctrees]

Definately, you need proper vent.

Otherwise ---

If you spend time Googling this, you will find the "too much slope and water outruns turds" is a total false old wives tale.

Ya, I read you don't have turds in your urinal (hopefully), but the thread went to that old story.

Further - I am not SURE about this part, but |I do not think any plumbing codes have a upper limit on slope, that supports what I said above.

The only exception to the above - Depending on your water input to drain, if the slope is TOO great,AND the pipe is like "small" for that volume, it MAY **** out your trap from the velocity "pull" of the water.

Don't trust me, Google it for yourself. Marc

And corn in the drain is no exception to this.

 

[ishiboo]

How many toilets/etc. have a vertical drop under them? Let alone urinals, sinks, etc. mounted up higher that drain in the wall.

Clearly a venting issue.