Forcemain Tie in 3

[Kyle406]

I am a contractor that has to tie into an existing 12" sewer forcemain. The tie in is for a temporary bypass that needs to be installed while we build a new wet well lift station in the current location of the main. In order to tie on, I will need to cut the pipe, allow the effluent to drain, and make the connection for the temp bypass. My question is: How can I drain this forcemain without allowing effluent into my excavation? Further, I am being asked to keep our "down time" to 30 min or less as we make this bypass connection. Any suggestions?

 

[rconner]

Am curious why must contents 'drain" -- any chance for wet tap and linestop?

 

[bimr]

To meet the proposed schedule, you will need to use a wet tap and linestop.

 

[OneManWolfpack]

You could line the excavation and use a vac truck to pump it out.

 

[stanier]

Fit some clamp on tees, hot tap the line and effect the bypass. When built close the valves on the hot taps and blind flange. If you are not experienced in this type of work there are specialist hot tap comapnies around with all the gear.

We successfully did hundreds of such bypasses for Sydney Water.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[dicksewerrat]

Why do you have to build the new wet well on the location of the existing main? If the existing pipe is under pressure now, I would leave it alone and move the new pump station off to the side. Do you have a drawing to post?

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[johnwill65]

I agree with the other two posters--a wet tap is the only way to go--to maintain service keep the line under pressure and not 'lose' anything in the excavation. Draining a 12" sewer main (at full each running foot contains about 0.8 gallons) could mean a lot of draining depending on how much you can isolate around the proposed break--and then you have to dispose of the wastewater. A good wet-tap contractor will do this seemlessly and without any service interruption.