P-Trap to vent minimum, Weir to Vent question

Users who are viewing this thread

mahuska

New Member
Messages
26
Reaction score
0
Points
1
Location
iowa
When sizing the weir to vent minimum on a P-trap is it measured from liquid edge in trap to start of vent inner diameter (=> than 2X trap arm diameter)?
 

Asktom

Member
Messages
745
Reaction score
32
Points
18
Location
Victor, MT
It is measured from the liquid edge to the start of the vent, but it is impossible to not meet code requirements given the configuration of the fittings available. Set that quandary aside and move on to the next one.
 

mahuska

New Member
Messages
26
Reaction score
0
Points
1
Location
iowa
I have a tight shower location using a Kerdi line drain and if you use 2 pipe diameters as the minimum then the weir to vent distance is 5.75. If I just put the P-trap right on the 2" tee the distance is 3.75.
5.75.jpgtoo close.jpg
 

WJcandee

Wise One
Messages
3,182
Reaction score
170
Points
63
Location
New York, NY
I have a tight shower location using a Kerdi line drain and if you use 2 pipe diameters as the minimum then the weir to vent distance is 5.75. If I just put the P-trap right on the 2" tee the distance is 3.75.

I don't know what your pipe size is, but the minimum vent distance is never going to be 5.75. It's 2 pipe diameters -- inner diameter. 1-1/4" pipe will be 2.5" minimum. 1-1/2" pipe will be 3 inches. 2 inch pipe will be 4". 3 inch pipe will be 6 inches. See page 3 of this document: Plumbing-and-Trenching-for-Homeowners---2018 (klickitatcounty.org)
One thing that is slightly confusing about that document, however, is that it says the minimum "trap arm" distance is whatever, but it illustrates the measurement for meeting code the correct way, then illustrates the "trap arm" as a different distance. The measurement you want is the illustration that shows the distance as being from the inside of the weir to the outer wall of the vent. not the "trap arm" markings under the connection points.
 
Last edited by a moderator:

mahuska

New Member
Messages
26
Reaction score
0
Points
1
Location
iowa
Ok inner diameters make a lot of sense. 2 in pipe for a shower.
2013-08-24 09.32.34.jpg
 

hj

Master Plumber
Messages
33,600
Reaction score
1,037
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
Unless you have an "anal retentive" inspector with a ruler, no one will ever check it , at least none have ever turned my installations down even with a trap tight to the tee.
 

hj

Master Plumber
Messages
33,600
Reaction score
1,037
Points
113
Location
Cave Creek, Arizona
Website
www.terrylove.com
Don't you just love idiots who post a long gibberish filled post in a foreign language, and then repeat it several times to be sure we don't miss it?
 

Jamie Smith

New Member
Messages
1
Reaction score
0
Points
1
Location
Virginia
Unless you have an "anal retentive" inspector with a ruler, no one will ever check it , at least none have ever turned my installations down even with a trap tight to the tee.
Just had one today...
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks