Tying a forced main into a sanitary line via a manhole
Tying a forced main into a sanitary line via a manhole
(OP)
I am installing a new forced main (10" polyethylene) of a water treatment's facility, which will tie into the municipality's 24" sanitary sewer line. The suggested tie in point is at precast concrete manhole. The manhole is 20 feet deep.
The municipality's water authority is worried that the forced main line who jet water to quickly into the manhole and wear away at its integrity. I am designing the pipe such that the discharge velocity of the fluid will be less than 5 ft/sec.
How could I make the tie in to this manhole? Does anyone know of any available detail drawings viewable on the web?
Any help would be appreciated.
The municipality's water authority is worried that the forced main line who jet water to quickly into the manhole and wear away at its integrity. I am designing the pipe such that the discharge velocity of the fluid will be less than 5 ft/sec.
How could I make the tie in to this manhole? Does anyone know of any available detail drawings viewable on the web?
Any help would be appreciated.





RE: Tying a forced main into a sanitary line via a manhole
Extend the downward portion of the tee/wye down. When at the invert elevation turn again horizontal and enter the wall of the manhole and continue through the MH into the shaped invert/outlet pipe, (assuming larger diameter like 18").
RE: Tying a forced main into a sanitary line via a manhole
If the discharge point is the control point, then every foot above the manhole invert is more head you'll have to pump and over the lifetime of the installation, it will cost more in electricity, etc. to pump the extra 10'-15' of head than it will to install the forcemain at the bottom of the manhole.
If the discharge point is not the control point, then you have gravity flow into the manhole and can design accordingly.
RE: Tying a forced main into a sanitary line via a manhole