ROT Can Cause Duct Issues - Short #160

HVAC School - For Techs, By Techs · Apr 18, 2023 · 6m

In this short podcast, Bryan explains how rules of thumb (ROT) can cause duct issues. He talks about the role of friction rate in duct design as well as its intent and limitations.

Friction rate is a value located on duct calculation tools, including Ductulators. We use friction rate to predict the operating static pressure of the system, but it is often misapplied when people design their ductwork around rules of thumb. The friction rate is expressed in inches of water column ("WC), which we also use to measure static pressure. However, the operational static pressure and friction rate are…