I'll let one of my "secrets" out of the bag.
There is a free software download for windows PC from Bell and Gosset call "System Sizer"
It is a software version of the old plastic wheel calculator I have been using for the past 30 years.
It is good for steel and copper pipe.
It also has a good design manual with it.http://completewatersystems.com/brand/b ... tem-syzer/
A little knowledge can be a dangerous thing, so read carefully.