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Large size wet-tap connection to force main

Large size wet-tap connection to force main

Large size wet-tap connection to force main

(OP)
I am currently in preliminary design for a new treated effluent discharge pipeline. The new pipeline will likely be in the 42" to 48" diameter, and the downstream terminus will be a connection to an existing 96" RCP outfall pipeline force main, operated by a joint powers agency. The force main owner agency would like the connection to be a 45-degree horizontal wye type connection.

I would prefer to make the connection without shutting down the 96" outfall pipeline. Does anyone know if a wet-tap type connection can be made at a 45-degree angle, at this size? I anticipate that we will have to spec some kind of custom tapping sleeve or concrete connection collar, but I'm not even sure that tapping equipment exists that can do what I want.

Thanks for your help.

RE: Large size wet-tap connection to force main

Comming from a "hands on" contractors background, I don't know of any type system to "wet tap" an RCP line of that size.

How much flow has it now? Can it be baffled or bypassed any at all?

If there is a way I would like to know but I suggest you speak with a local qualified contractor.

RE: Large size wet-tap connection to force main

(OP)
Thanks for the reply. I've been looking around since I made this post last month, and haven't been able to find any way to do a wet tap.

Our current thinking is to build a concrete pressure structure around the existing 96" RCP, and cast an angled flanged spool fitting into the top. Then at low-flow periods when the force main operates as a gravity line, cut into the RCP from inside the spool. If the work takes longer than one low-flow window, we can blind flange the spool fitting and come back the next day.

Now I've got to figure out how to keep pieces of the RCP from dropping into the 96" and possibly damaging the outfall works downstream.

RE: Large size wet-tap connection to force main

Your plan sounds like a winner to me.

How large pieces are acceptable? Wouldn't a good cut (by pros) make it clean for pulling out the tie in section?.. Followed by dowling 96" in the building of the junction structure?

RE: Large size wet-tap connection to force main

(OP)
You're right. I'm pretty sure that if we have a qualified contractor, we're unlikely to have problems. I've just never written a spec for this type of work before, and want to make sure I get it tight.

Thanks again for your input.

RE: Large size wet-tap connection to force main

Where is the project located?

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