Connecting 12" Main to Existing 12" Main
Connecting 12" Main to Existing 12" Main
(OP)
Have a project where they want to loop the water line from one street with a 12" line to a cul-de-sac with a 1o" line. The proposed water line will be 12". When tapping to the existing 12" line, is it easier/better to use a tapping sleeve and valve or shut the line down and install a 12"x12" tee?





RE: Connecting 12" Main to Existing 12" Main
If the service area includes businesses such as hospitals, schools, etc. then it may not be practical.
That is something that you have to evaluate with your project.
Note that procedures for disinfection of the water main may take some time.
RE: Connecting 12" Main to Existing 12" Main
If you can get away with shutting off the water it will be cheaper. Usually the utility company will decide if they will allow you to shut off the water.
RE: Connecting 12" Main to Existing 12" Main
RE: Connecting 12" Main to Existing 12" Main
RE: Connecting 12" Main to Existing 12" Main
It's not accurate to say that a 12" tap can't be done. Taps up to 16" are commonly performed, although I've never had occasion to wet tap anything bigger than 16". Mueller has the sleeves up to 36".
I do have to back off my earlier statement that you can't tap a 12" into a 12". I should have said it's not good practice and there is a high risk of splitting the pipe.
Also remember to consider joint restraint or thrust blocks.
RE: Connecting 12" Main to Existing 12" Main
Mike McCann, PE, SE (WA)
RE: Connecting 12" Main to Existing 12" Main
It's been a while, but if I remember correctly the 8" tap to 12" reducer only cost about 5 psi at 1500 gpm.
Two 8" taps and a tee could be almost as bad for head loss.
RE: Connecting 12" Main to Existing 12" Main
Mike McCann, PE, SE (WA)
RE: Connecting 12" Main to Existing 12" Main