• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Find the violations for this water closet installation

jar546

jar546

Forum Coordinator
Joined
Oct 16, 2009
Messages
11,087
Location
Somewhere Too Hot & Humid
What you are looking at is a water closet install and vent on this horizontal run.

Closest to you is the cleanout cap with the WC vent going straight up from a sanitary T on its back (ok for a vent). Downstream you see the water closet coming down and into a Wye.

Let's here some opinions and more specific code references on this one.

pipe2.jpg
 
1. More pipe support

2. Developed length??

3. 6" above flood level before going horizontal?

4. Concealed cleanout.

Am I close?
 
In the UPC world, this would be called a "flat vent" (not a code word, but rather plumber slang). This vent would flood in the case of a back up, and therefore requires approved drainage fittings (no san tees on their back) where connecting below flood rim, and the vent must connect above the centerline of the drain (section 905). The '06 ushered in horizontal wet venting in dwellings only (in bathrooms only as well), but i don't see it often. There are official interps on the horizontal wet vent that would also not allow for this configuration.
 
Glennman--I was aware that the IRC allowed wet venting of a dwelling bath and agree there needs to be a sweep fitting rather than a san tee where the vent goes up. My question is: does the UPC allow a residential bath to be properly wet vented or only the IRC?
 
Robert, The UPC allows a horizontal wet vent in bathroom groups only, and only in dwellings. There was alot of stink about it. If I recall, Washington State came close to not adopting the UPC because it didn't allow the horizontal wet vent. They changed it in order to become more competitive with the IRC (from what I've heard). The vertical wet vent can be done in any group or condition as long as it is installed properly (same floor, upsize piping, etc).
 
I'm confused.

How is the horizontal pipe between the san tee and the wye for the WC a wet vent. It does not convey any waste.

To me it seems this is not a wet vent, in that no fixture is discharging into the pipe upstream of the WC. By the same logic, would not the vertical vent coming out of the san tee be considered a vertical wet vent?

I believe the piping between the WC and the vertical vent is a dry vent and therefore incorrect. As stated, there is no fixture discharging waste to wash the piping, such fixture being required (in my opinion) to make this vent "wet".

If that were a wet vent, I don't think we would need a provision for any vents to connect above the midline of the pipe per P3104.3 [2003]-- we could just call that portion of the connection a wet vent.

I had to struggle with learning venting by reading the books, so I will honestly admit this is not my strong point. I would fail this and cite P3104.4 [2003], unless you guys can convince me otherwise (always learning!)
 
It is not a horizontal wet vent, but I brought up the subject of horizontal wet venting because it has some of the characteristics of one. If the upper portion had a fixture dumping into it, it would be one. However, the rest of it would not comply based on official interps from IAPMO.

In this case, if the drain was to plug, it would flood the vent, and therefore would require all drainage fittings per the UPC. The way this is plumbed, the water from the toilet would flood the vent to a certain point even if there wasn't a plug in the line. The point here is that the vent cannot be in the same horizontal plane as the drain.

UPC 905 pretty much covers it. I don't know about the IPC.
 
Glenman is correct with regards to UPC below is an excerpt from the 2006 UPC training manual

905.2 Although vent piping may be installed in a horizontal position, vent connections may be hori­zontal. The `invert' (interior bottom surface of a pipe) of a vent must be above the centerline of the drainage piping to which it is connected. The centerline of a drainage pipe is considered to be the mid-point (1/2 the diameter) of the pipe; an eleva­tion within a drain line that would normally not be exceeded except during surge conditions. The objective is to prevent the flow through the drainage system from detouring into the vent piping. This is best achieved by ensuring that the elevation of each horizontal vent's invert is sufficiently above the drain line (trap arm) served so that the vent will remain 'dry' unless a drain line stoppage creates a generally flooded condition in the underfloor DWV system. Vent inverts, which are below the drain line trap arm centerline, are known in the plumbing industry as `flat' vents. Under no circumstances are such installations permissible. Except as otherwise provided by Code, the greater the differential between drain line and vent pipe inverts, the better. It is important to remember that water flows in the direction of least resistance. Elevation differentials create a natural resistance to flow in that water will never flow against gravity unless it is being pushed by a force greater than gravity. Every inch of rise between drain line and vent pipe inverts increases the amount of gravitational resistance to be over­come, thereby reducing the probability of vent pipe flooding.



 
You must log in or register to reply here.
Top