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 ...

MANY YEARS AGO, I paid good money out of my own pocket to learn how to design a duct system. I won’t say to whom I paid this money, because I got ripped off. What I “learned” was how to find .1 on a ...