Fired Heater Learning Center

Ducting Pressure Drop Calculator

Ducting Pressure Drop Calculator

The following formulas and coefficients are from the American Petroleum Institute Practice API RP533.

Duct Piece Type: Shape:
Inlet Diameter, ft: Outlet Diameter, ft:
Inlet Width, ft: Inlet Height, ft:
Outlet Width, ft: Outlet Height, ft:
Radius Of Turn, ft: Incl'd Or Turn Angle, Deg:
Roughness Factor: Hght Of Col Or Lgth Of Run, ft:
No. Of Miter Pieces:
Gas Flow, lb/ft2: Viscosity Of Gas, cp:
Density Of Flue Gas, lb/ft3: Density Of Ambient Air, lb/ft3:
Velocity, ft/sec: Velocity Head, inH2O:
Coefficient: Pressure Drop, inH2O:


The formulas and correlations presented herein are all in the public domain and are to be used only as a learning tool. Note that any product, process, or technology in this document may be the subject of other intellectual property rights reserved by sponsors or contributors to this site. This publication is provided as is, without any warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of fitness for a particular purpose, or non-infringement.

The formulas, correlations, and methods presented herein should not be considered as being recommended by or used by the sponsors of this site. The purpose of this site is educational and the methods may or may not be suitable for actual design of equipment. Only a fired heater design engineer is qualified to decide if a calculation or procedure is correct for an application.