3" ABS toilet drain - height change - trap arm

Rousifier · 02-19-2011, 03:45 PM

Ever mindful of the need to avoid siphoning the p-trap under my new shower, I think the maximum developed trap arm for my upstream 3" toilet drain is 12'. If that is the case, I have a 3" height adjustment to do as the new location crosses over a 4" line that is that much higher. Does making a height adjustment with two 22 1/2" ells affect the allowable length? The toilet is now 6' from the 2" vent. So, it would go about 2' from the toilet at 1/4" per foot, drop about 3", then continue into the existing drain, again at the approved slope. Does that make sense? Is it allowable under Canadian or other codes? Does there need to be something placed between the ABS pipes or can they rest one on top of the other?

Thanks in advance for any assistance.

Alan · 02-19-2011, 11:11 PM

Not sure about your jurisdiction, but a 3" trap arm out here maxes out at 6', and your vent has to come off the top of the trap arm, meaning any offsets vertically between the vent and the trap are not allowed, and horizontal offsets up to 135* ARE allowed.

Rousifier · 02-19-2011, 11:41 PM

Thanks, Alan, I really appreciate the help.

R.