ECONOMICAL SIZING OF DISTRIBUTION PIPING.

An equation for the most economical pipe diameter for a distribution system for water is

D=0.215*(fbQ³_aS/aiH_a)^1/7

where

D= pipe diameter, ft (m)

f =Darcy–Weisbach friction factor

b =value of power, $/hp per year ($/kW per year)

Qa= average discharge, ft3/s (m3/s)

S =allowable unit stress in pipe, lb/in2 (MPa)

a= in-place cost of pipe, $/lb ($/kg)

i =yearly fixed charges for pipeline (expressed as a fraction of total capital cost)

Ha =average head on pipe, ft (m)