One of our most popular catalog items! This durable two-sided plastic sizing wheel comes with a complete instruction manual for residential and commercial duct-sizing procedures. Designed by Hank Rutkowski.
Sizes metal ducts, lined metal ducts duct board airways, and wire helix ﬂexible ducts.
Converts round shapes to equivalent rectangles.
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