For the past 50 years, engineers have been “designing” duct systems. Quite often, they were not actually designing the systems, but were sizing duct the duct according to some rule of thumb. The rules ...

In 1948, research by R.G. Huebscher established flow resistance for different shapes of ductwork at equal velocities, which allowed the creation of the duct-sizing calculator or “Ductulator” for ...