DWV Question

[Nate R]

My Tub and Lav drains will combine, and then have to go through 2 elbows before they drop vertically. When should I use long sweep elbows, and when are short ones OK? Or should I use long sweep whenever possible?

[jimbo]

All fittings on a drain line must be what code calls "drainage type fittings" which means long sweeps. "short sweeps" are only used in dry vents, and in water supply piping.

[Spaceman Spiff]

Short bend aka vent bend (Charolette #300-A) = vent only
Sanitary bend aka sanitary ell (Charolette #300) = drain and vent
Long sweep (Charolette #304) = drain and vent

http://www.charlottepipe.com/Documents/DimensionalCatalogs/Plastic_Pipe_Fittings.pdf

Around here the cheapest is the sanitary bends, then vent bends, then long sweeps. Sanitary bends are used for almost everything here...

[Nate R]

I was comparing # 300 and 304. I knew 304A was vent only, but I should've posted pics to be more clear.

That said, where would one use the 304 (long sweep)? Wherever possible to slow flow as little as possible?

[Nate R]

That said, where would one use the 304 (long sweep)? Wherever possible to slow flow as little as possible?

Anyone? ???

[hj]

The long radius 304 has nothing to do with slowing the flow. It is to give the least resistance to flow and is used for most drainage turn applications, and can be used for all turns anywhere in the system. The drainage ell 300 is for venting and any location where a horizontal drain line turns down into a vertical plane. That is the only "legal" use of a short radius elbow in the drain portion of a DWV system.