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Ashrae Duct Fitting Database


`How to Use the ASHRAE Duct Fitting Database for HVAC Design`

`If you are a design engineer working with HVAC ducts, you may have heard of the ASHRAE Duct Fitting Database. This is a cloud-based tool that provides loss coefficient tables for more than 200 types of duct fittings in both I-P and SI units. In this article, we will explain what the ASHRAE Duct Fitting Database is, how it works, and how you can use it to optimize your duct design.`

`What is the ASHRAE Duct Fitting Database`

`The ASHRAE Duct Fitting Database (DFDB) is a product of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), a professional organization that sets standards and guidelines for the HVAC industry. The DFDB is based on ASHRAE Standard 120-2017, which establishes uniform methods of laboratory testing of HVAC ducts and fittings to determine their resistance to airflow.`

`The DFDB contains loss coefficient tables for more than 200 round, rectangular, and flat oval duct fittings, such as elbows, tees, reducers, dampers, and diffusers. Each fitting has a pictorial outline and a description of its dimensions and parameters. The loss coefficient is a dimensionless number that represents the pressure loss caused by the fitting per unit length of duct. The higher the loss coefficient, the more resistance the fitting offers to the airflow.`

`How does the ASHRAE Duct Fitting Database work`

`The ASHRAE Duct Fitting Database is accessible by annual subscription through a web browser or a mobile app. To use the DFDB, you need to enter the following information for each fitting:`


`The flow rate in cubic feet per minute (cfm) or cubic meters per hour (m3/h)`

`The duct size in inches (in) or millimeters (mm)`

`The fitting type and subtype`

`The fitting dimensions and parameters`


`Based on these inputs, the DFDB will calculate the loss coefficient and the pressure loss for the fitting. The pressure loss is expressed in inches of water column (in wc) or pascals (Pa). You can also view the calculation details and the table data for each fitting.`

`You can save your fittings into a project file, which can be stored and transferred. The project file contains all the input and output data for each fitting, as well as a summary of the total pressure loss for the entire duct system. You can also export your project file to Excel or PDF formats.`

`How can you use the ASHRAE Duct Fitting Database to optimize your duct design`

`The ASHRAE Duct Fitting Database can help you optimize your duct design by allowing you to compare different fittings and their effects on the pressure loss and energy consumption of your duct system. By minimizing the pressure loss, you can reduce the fan power required to maintain the desired airflow rate and improve the efficiency and performance of your HVAC system.`

`Some tips for using the DFDB to optimize your duct design are:`


`Choose fittings that have low loss coefficients and avoid fittings that have high loss coefficients.`

`Use round or flat oval ducts instead of rectangular ducts whenever possible, as they have lower friction losses.`

`Use smooth transitions between different duct sizes and shapes to avoid turbulence and flow separation.`

`Align fittings properly to reduce flow disturbances and pressure losses.`

`Use flexible ducts sparingly and only when necessary, as they have higher friction losses than rigid ducts.`



`The ASHRAE Duct Fitting Database is a valuable tool for design engineers who work with HVAC ducts. It provides accurate and reliable data on the pressure loss characteristics of various duct fittings in both I-P and SI units. By using the DFDB, you can optimize your duct design and improve the efficiency and performance of your HVAC system.` 061ffe29dd


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