ACCA Duct Calculation Slide Rule

This durable two-sided plastic sizing wheel (or "ductulator") comes with a complete instruction manual for residential and commercial duct sizing procedures. Designed by Hank Rutkowski. Uses: - Sizes metal ducts, lined metal ducts, duct board airways, and wire helix flexible ducts - Converts round shapes to equivalent rectangular shapes - Correlates available pressure with total effective length and friction rate (Manual D sizing calculations) - Converts velocity into velocity pressure and vice versa - Corrects for altitude and temperature.