Force Main Connection 1

[bank]

A business owner is in need of a place to discharge his wastewater. The local Utility District told him to tie into a force main owned by the school district that I represent. We have determined that the force main has capacity to handle the additional load. The question is, is it possible to tie directly into a force main? If so, can anyone offer suggestions on how, or point me towards any resources that can provide instructions on how to make it happen?

 

[francesca]

The forcemain is more than likely owned by the utility district, not the school district. Nevertheless, the answer to your question is "it depends, but probably not without at least a griner pump." If the forcemain is beyond all local high points and acts under gravity flow the entire path to the WWTP then you could probably connect directly to it, but that's a very unlikely scenario and just because it's downhill all the way it doesn't mean that the pipe isn't surcharged at the connecting point (or will be in the future) due to a high flow rate. I know of such a situation where the business owner was allowed to connect to a trunk forcemain with just a grinder pump as it was near to the end of the line and the surcharge was not too great.

 

[bimr]

You have not provided much information as to the requirements for your project. You should note that the state plumbing code typically requires separate service connections from each property into the utility sanitary sewers.

What you are talking about is a small plumbing project. Talk to a pump vendor such as Myers:

http://www.femyers.com/products/wastewater.html

Make sure that you buy a pump with adequate discharge head. The piping connection will probably be a Y fitting.

 

[SteveWag]

The easiest way (for the school district) would be to require the use a tapping sleeve and valve to connect to the force main. This can be installed while the main is in use and filled with sewerage, so the School District will see no inconvenience. A valve box should be installed over the valve operating nut. This valve will allow the School District to isolate the business in the event the business has a problem. As to the business, his Engineer needs to know the profile of the force main in order to size the pump(s). One more thing you may want to include is a check valve at the tap to control water hammer, but I normally don’t require one.

If you have contacts with either a water utility or utility contractor, find out where they buy pipe and fittings. These supply houses normally have a salesman that can offer advice on things like this. If you know the type of pipe used to construct the force main, a salesman could give you a manufacturer and number or name of the required fitting(s).
Steve

 

[redbridge]

The way I have always done this was to cut in a wye fitting and install a valve on the new line. You can drain the force main by turning off the pumps and opening the check valve. The wye fitting is incase you ever pig the force main. The business owner will need a pump.

 

[sjohns4]

Sounds like Steve hit the nail on the head. A pig will turn through a Tee, however, some folks dont like to do a full sized tap - for example you'll usually do a 16"X12" tapping sleeve & valve rather than a 16x16 for tieing two 16" pipes together.

Depending on the new business flow rate in relation to the schools you might be running a smaller force main connecting to a larger one anyway.

If your flow rate is low enough check out eOne pumps. If it's a bit more than an eOne can handle I too would turn to a Myers. If you go with eOne I'd recommend specifying the oil resistant stators.

 

[TBCEng07]

When you do your calculations, remember that your new pump will have to push the water in the utilities forcemain as well. Most grinder pumps have suffcient head capacities to overcome this type of condition, but check it.

Check Valves and Shutoff Valves are probably a good idea.