Dear Y Choi, You asked a ...

Dear Y Choi,

You asked a good question - however there is no one answer for your question.  Whether the full flow or part flow is critical to your sewer network - depends on the design of your network.  I attached a small Excel file with some of the calculations I used for both partial and full flow in the circular pipes (developed it at the time I was self studying the advanced hydraulics). The hydraulics plays a serious part in the sewer network design as well as provisions for maintenance (hydraulics deals with water - but there are a lot of objects in the sewers..).  Regards, Iouri