Understanding Pressure Loss in Ducts: A Comprehensive Guide

When it comes to ducts, pressure loss is an important factor to consider. Pressure loss is the amount of pressure that is lost due to friction as air passes through the duct. This loss is usually measured in inches of water gauge (Wg) for every 100 feet of duct length. The friction loss per unit length can range from 0.05 to 0.2 inches Wg, depending on the type of duct and the material it is made from.

Calculating the pressure drop due to friction for a straight length of duct requires taking into account several factors, such as the absolute roughness of the duct, the duct height, and the aspect ratio of the duct. Additionally, the size of the duct must be determined based on the allowable pressure drop. This can be done using Excel Solver or by tabulating large pressure loss samples with different duct sizes and then using interpolation to match the correct size. When designing a duct system, it is important to keep in mind that as airflow increases along the duct after each branch (or takeoff) closest to the unit, the size of the designed duct will increase so that the pressure loss per unit length remains constant at all times. This is why it is essential to use a duct size meter and pressure drop calculator when designing a duct system. The Medical Gas Pressure Drop Calculator, Rectangular Duct Aspect Ratio Calculator, Air to Volumetric Air Flow (CFM) Calculator, Cooling Tower Makeup Tank Calculator, Light Quantity Calculator (Lux), Linear Length Pipe Loss Calculator, and Duct Dimensioner and Pressure Drop Calculator are all useful tools for calculating pressure loss in ducts.

Additionally, there are premium versions of these calculators available that offer additional features such as the ability to switch between rounded values of common duct sizes or exact values, calculate losses for both rectangular and round ducts, show all working cells for troubleshooting, and hide them again later. By understanding pressure loss in ducts and using the right tools, you can ensure that your duct system is designed correctly and efficiently. With this comprehensive guide, you will have all the information you need to understand pressure loss in ducts and design an effective system.