Max Flow Through Water Main

NYplumber

Hi there wallies,

As with heating there are max flow rates for hot and cold water pipes in homes. Honestly I went off of feel and rules of thumb from years in the field when piping domestic water lines, haven't had an issue yet. I have a client with a specific sized water main and he wants a filter (most likely sand media filter) for all incoming water. With the size of this home and the MANY bathrooms its impossible to say lets take a worst case load (gpm) and use that. His fixtures can surely out draw his piping.

The water main is 1 1/4 in copper. With 60 psi street pressure, and max flow, what flow will this pipe support? I came up with a conservative number of 25gpm. Is there a size and gpm table somewhere on engineering toolbox? While I dont want to over engineer his filtration, I also dont want to under design.

Thanks in advance.

SWEI

Do you have a Cv (or pressure drop versus flow curve) for the filter? How much pressure drop is he willing to tolerate? That plus the equivalent pipe length should get you close.

uge

A 1-1/4" line can flow 20 gpm with minimal pressure drop. With 60 psi street pressure you should have no problem installing the filter.

NYplumber

Have 3m working on it for him. Seems like three filters in reverse return piping will suffice.