The duct calculator
	This module replaces friction charts, 'slide rules', and round-to-rectangular equivalent charts for metal duct, vinyl flex, and duct board.  All inputs and outputs occur concurrently in IP and SI units, which you can turn off as you wish.

The screen controls are simple, and self-explanatory.  Each input text-box accepts both direct numeric entry, and well as 'dialing-in' values by scrolling up and down via the arrow keys on your keyboard.

All fields update concurrently in real-time as you input data.

Just like a slide-rule, you input CFM ( or metric M3H / L3S ), and any other factor ( friction, velocity, etc )   

You can at any time capture a segment, with a name if you choose, to the running cumulative report, for saving, printing, emailing, etc.

The report offers 'short form' and 'long form' formats.  The screenshot below is the 'long form' report for a duct segment.