Question about drainage slope

[jjgmorgan]

Is there a maximum vertical drop distance allowed for a drain pipe? I have a 2" drain pipe for my kitchen sink. Is runs 10 feet at 1/4 per foot slope. I now need to drop vertically to the 3" main drain line.

 

[hj]

If there were, the skyscraper office buildings would not be able to have plumbing installed.

 

[Sponsor]

 

[Asktom]

After the vent there is no limit on steepness of slope, before the vent (trap arm) is a different ballgame with different rules.

 

[Jim Mills]

Don't go over 90 degrees!

 

[jjgmorgan]

Lets say a drain pipe runs 8 feet, you have a 2" slope. The pipe then goes 90 and drops two feet. Another 90 puts it running horizontal again. What would be the slope at that point for another 8 foot run? It it going to be 2" or 4"?

 

[Jim Mills]

2" miinimum (1/4" per foot)

 

[Jadnashua]

Or, IOW, you need a MINIUMUM of 1/4" per foot on any horizontal run - essentially forget the verticals or diagonals, or whatever, as they ARE above the MINIMUM...the slope is for ALL parts of the system. Nowhere can it be without slope downwards, and should never try to go up again unless you have a pump there.

 

[hj]

quote; What would be the slope at that point for another 8 foot run? It it going to be 2" or 4"?

Every horizontal section is computed individually, therefore its "minimum" slope would be 1/4"/ft, or 2". The original 8' section has NOTHING to do with it, once it changed elevations.

 

[jjgmorgan]

Thank you, that was well put, I understand.