Hey Ed, What Is the Minimum Velocity in a Duct System?

In this edition of "Hey Ed", Ed discusses what the minimum velocity is in a duct system?

Hey Ed, what is the minimum velocity in a duct system? The minimum velocity in a duct system is there isn’t one, there is a conclusion in the back of manual D that states there are many things to worry about when designing a comfort system, but low velocity is not one of them. So essentially, what they are saying there is, there is no minimum velocity. What we’re always going to do is make sure that our branch runs have the proper CFM flowing through them, and the important part is when we select the grill, that we select a grill not based on appearance but performance, so we wanna make sure we get the proper throw and spread out of it if it’s being fed with the proper volume of air then we’ll get that predictable or anticipated spread and throw out of the register, and that’s the way I see it.