I'm just trying to get a general idea of how other people size their units, specifically the static pressure.
As a preface, I know Fluid Dynamics relatively well and understand what static pressure, velocity pressure and dynamic pressure are. What I'm wondering is how companies(building engineers, design build contractors and/or consultants) select their units and what kind of analysis is done.
What I think actually happens is people select units based on experience. They know the amount of ductwork involved and select a static pressure accordingly.
Does anyone actually calculate the pressure losses associated with the Reynolds Number, flow rate, friction factor, ductwork material, etc?
In general, how do you select your units static pressure?