Vent support question

[Silversurfer7]

I'm getting ready to add two san tees to my existing, 35 yr old, steel vent - to allow a double lav to be installed. Wondering best way to support vent, when a portion of it is cut out for san tees? Is this even needed?

Prior to cutting the vent I'm, tentatively, thinking of attaching a two piece, clam shell, clamp/brace to the wet vent to facilitate the vent being supported by the adjacent studs. Perhaps there's a better or simpler way I'm overlooking? Any suggestions are appreciated.

Thanks in advance,

Robert

[hj]

Exactly what do you mean by "wet vent"? A normal wet vent would not be in a location where you could connect two sinks to it and still be within the permitted distance from the vent. Why are you using two tees instead of a double fixture fitting?

[Silversurfer7]

I should’ve omitted the "wet" out of the vent description. My existing drain & vent has one lav, about ~ 2 ft away, plumbed to it via trap arm. The vent, serving that lav, proceeds up to the roof - and has nothing else, up stream, plumbed to it. The drain proceeds down to the lower floors.

Two san tees would be better than a double fixture fitting, for my application, due to space limitation. Namely, on each side of my vent stack there are other, lower, units vent stacks. This is in a condo building.

Please forgive my inaccuracies. Any advice is appreciated. Thanks!

[dubldare]

http://www.terrylove.com/forums/show...7210#post27210


The wet vent is the vertical distance between the two tees.

Although the following images only refer to a single fixture installation, they do show why wye's are not acceptable for fixture venting, at least when vertical.

[dubldare]

As far as support for the vent, either a riser-clamp or a wrap or two of band iron should suffice.

[Silversurfer7]

dubldare,

I really appreciate all your help! Thanks for the insightful pictures & education.

[Silversurfer7]

Wondering if, per code, a vent stack for a multistoried building is to be supported at specified increments? Seems to me is has to? Perhaps every 10 feet or at the top of each floor? I'm asking, again, prior to cutting my lavs steel vent stack, in the middle of the third floor of my four story building.

I would imagine that for multi story buildings a number of pipes would need to be plumbed/fastened together to form the vent stack. Based on this assumption, I would tend to think that this piping would, at a minimum fasten, together at flanges which are supported by the buildings framing?

Please let me know if you you can help me by answering this support question.

Many Thanks,

Silver

[hj]

A double fixture fitting is neither a cross, which is not permitted, nor a double combination Y-1/8 bend, which is not permitted either. It is a fitting designed just for what you are doing.

[Silversurfer7]

Thanks to you HJ, dubldare & Terry of course, I've been trying to figure out how I can shoe horn in a dbl fxtr ftg, for my application, as recommended.

Pickle I'm in is that, inside the wall, my lavs Ø1.5”, steel vent is flanked by identical vents on each side. These other two vents are from units on lower floors of my building. A 2x4 wall stud is sandwiched between the vent farthest to the left & my lavs’ vent. Cutting anything other than my lav’s vent is something I'd like to avoid. Due to their close proximity to each other and my desire to minimize cutting existing vent stacks & studs - I believe one of my best prospects is to have the dbl fxtr ftg offset approx ~ 4” (using 45’s) out of the existing wall? What do you guys think? I'm unsure about code problems with this approach however? Actually I’m not too crazy about the offset prospect and am debating, what I believe to be, my only other option - stacking two san tee's & keeping everything inline and inside the existing wall?

Concern is if I have the dbl fxtr ftg offset as described, will the two SS banding clamps (to securing new PVC piping to the existing steel stack) be enough to handle the weight – from the existing, heavy steel, vent stack above it?

This all goes back to wondering about standard practices for vertical vent supports. Not to be confused with lateral support. I’d like to think the vent stack is supported at each walls’ sole plate or the top, double plate, of each framed wall? In other words – at each floor or every 8 to 10 feet.

Please let me know what you think, including and insights on the offset prospect or the plan of stacking two san tee's.

As always I appreciate all your help and admire your patience with someone possessing less than professional experience.

[Silversurfer7]

From what I've researched it appears that per IRC (T2424.1 & T2605.1) vertical spacing for threaded steel water pipe is 10 ft.

Additionally, per UPC (T3-2) supports should be every other story or every 25 ft.

Am I reading this correctly?

Please advise

[toolaholic]

There should be a riser clamp resting on the bottom plate of each floor.
In the real world you don't know that! Install your own clamp below your top plate and use additional hardware to attach to both side studs or leged into top plate . has to be SOLID good luck