Can I Avoid The Revent? - Plumbing - DIY Home Improvement | DIYChatroom

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Plumbing


Thread Tools Display Modes
Old 12-03-2010, 01:47 PM   #1
Join Date: Dec 2010
Posts: 1
Rewards Points: 10

Can I avoid the revent?

I'm in the process of redoing my kitchen, and the placement of the kitchen sink, which lies below a casement window, is giving me a hard time figuring out how to lay the plumbing for it. I would prefer not to cut into any studs around this area, since that would mean cutting into studs that are supporting the header of the window, which belongs to a load bearing exterior wall. I can't use AAV's in my area, nor can I use loop vents, which are meant for islands. So initially, I was stuck with doing a rather painful revent to the adjacent wall which contains the main soil stack, which would mean cutting into some joists, which I also would prefer not to do.

So I was reading the 2009 National Standard Plumbing Code from the PHCC which is what the NJ Uniform Construction Code Act follows, and that, in turn, applies to my town, and I found these sections under Chapter 12:

I bolded the areas which I think apply to my questions below.


12.8.1 Venting of Fixture Drains
Fixture drains shall have a vent so located that the vent connects above the top weir of the trap and the developed
length of the trap arm is within the limits set forth in Table 12.8.1.
(1) Water closets and similar siphonic  xtures.
(2) Combination waste and vent systems. (see Section 12.17)
(3) Vents may be connected below the top weir of the fixture trap if the following conditions are met:
a) The vertical section of the drain pipe shall be at least one pipe size larger than the trap inlet size.
b) The horizontal pipe connected to the trap outlet shall be at least two pipe diameters long.
c) The developed length of the trap arm shall not exceed the values in Table 12.8.1.

Table 12.8.1
Size of Trap Arm (Inches) Length Trap Arm to Vent Slope Inches per Foot
1- 1/4 - 3 6" - 1/4
1-1/2 - 5 - 1/4
2 - 8 - 1/4
3 - 10 - 1/8
4 - 12 - 1/8

This table has been expanded in the "length" requirements to reflect expanded application of the wet venting
principles. Slope shall not exceed 1/4" per foot.


12.12.2 Horizontal Branches
Three lavatories or one sink within 8 feet developed length of a main vented line my be installed on a 2" horizontal
waste branch without reventing, provided the branch is not less than 2 inches in diameter throughout it's length
and provided the wastes are connected into the side of the branch and the branch leads to its stack connection with a
grade of not more than 1/4 inch per foot.

The proximity of the kitchen sink to the main soil stack is way less than 8 feet. I also have two secondary vent/drain vertical stacks that are 2" diameter that lie on the same wall as the main stack line, not far from it.

So I have the following questions:

1) Does the above code imply that I may be able to simply connect the sink drain to the main soil stack or any of the secondary lines without creating a revent for the sink if I simply follow the size and diameter dimensions for the horizontal branch?

2) Would it also be possible to run this horizontal branch that connects the sink drain to any of the vertical stacks on the adjacent wall (main soil, or the 2 secondary 2" ones) below the kitchen floor? My basement lies directly below the kitchen floor. This way I won't need to alter any walls in the kitchen for this connection.

3) What size will the trap for the sink be required to be if this horizontal branch has to be 2"? In other words can the trap stay 1 1/2", but convert to 2" once you're at the top weir of the trap?

Thank You,


amadog is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Avoid T&G for squeaks? jconti Flooring 20 06-15-2010 02:16 PM
Is it possible to do an entire home interior in cement board & avoid flimsy drywall? jws3 Drywall & Plaster 30 09-13-2009 01:01 PM
best material to put on top of bare soil to avoid weed growth? KUIPORNG Landscaping & Lawn Care 10 09-03-2008 09:51 AM
How to avoid audible buzz with dimmer switch wkend3 Electrical 4 08-27-2008 09:44 PM
How to avoid getting waves when mudding my joints... yummy mummy Building & Construction 11 05-27-2008 09:46 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1