Lift Station with downhill forcemain

[cswimchic]

I am trying to determine if a pump currently being used in a lift station will provide sufficient head if the lift station is moved. I was reading through the design report for the original lift station and noticed that when determining the required head needed only 200 feet of the actual 2600 feet of force main was used to calculate the friction loss. The forcemain runs downhill so the only reason I could find for 200 feet was the fact that each time the pump turns on the maximum volume of sewage that it will push through the forcemain is 200 linear feet.

Is calculating friction loss for only the 200 feet versus the full 2600 feet since the force main runs downhill correct?

 

[francesca]

As long as the sewerage can gravity flow at the required rate in the pipe and there are no other pumps going to that pipe, then yes, that is correct.

 

[bimr]

Agree with francesca, that design scenario is appropriate if the force main transistions to a gravity sewer at the high point of the system.