Too Much Slope in Sanitary Drainage in Plumbing Codes?

[Diehard]

Results of my search of code requirements for maximum slope on Sanitary Drainage Pipe.(Some think 1/4" per foot is the max. by code.)
Reference is made to the IPC(International Plumbing Code)

The code includes a chart for MINIMUM slopes of sanitary Drainage pipe. It does not address MAXIMUM slope except under the Vent section.

It actually shows 1/2" per foot slopes in charts when referring to maximum fixture unit loads. So we know that definitely is an acceptable slope.

I found where others had made INCORRECT references to requirements stated under the Venting Section. One which applied to Circuit Vented Branches, 914.3., included below.


And another which applied to Combination Waste and Vent System, 915.2.1., included below

 

[frodo]

This PDF might help you in understanding why a pipe can not have screaming fall.
I have always said, If the fall is to extreme, the water will leave the solids behind.instead of washing the solids away

http://codes.iapmo.org/docs/2015/UPC/articles/The Evolution of Self-Cleaning Drainage in the Codes.pdf

 

[frodo]

The 1/2'' per foot is concerning a combination waste and vent system
does it mention a 1/2'' per foot in a sewer line? or building drain?

the 8/3 slope is in the vent section, which only drains rain water or condensation
no solids

 

[Diehard]

This PDF might help you in understanding why a pipe can not have screaming fall.
I have always said, If the fall is to extreme, the water will leave the solids behind.instead of washing the solids away

http://codes.iapmo.org/docs/2015/UPC/articles/The Evolution of Self-Cleaning Drainage in the Codes.pdf

1. Sorry but I see no reference to "too great of velocities"(extreme fall) in this referenced article.

2. My comments were only addressing the fact that there is no code restrictions on too great a slope.

3. The 1/2" per foot I mentioned was relative to Building Drains and Sewers in this chart. Not under the waste and vent section.

4. My reference to the Circuit Venting Section and the Combination Waste and Vent System was pointing out where people were incorrectly quoting these examples. When in fact these greater slopes have nothing to do with solids collecting but rather address venting concerns.

 

[Diehard]

The 1/2'' per foot is concerning a combination waste and vent system
does it mention a 1/2'' per foot in a sewer line? or building drain?

the 8/3 slope is in the vent section, which only drains rain water or condensation
no solids

???
The circuit vent is not for rain water. A circuit vent connects to a horizontal drainage branch and vents two traps to a maximum of eight traps or trapped fixtures connected into a battery.

 

[frodo]

A vent drains the condensation and rain water that drips down the pipe from the roof
it does not matter the slope, it has no solids

 

[Diehard]

A vent drains the condensation and rain water that drips down the pipe from the roof
it does not matter the slope, it has no solids


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Sorry I have no idea where this discussion has gone. Except on a tangent perhaps. Have a good evening.