In a tee or junction, the loss coefficient for the air going straight through ( C = 0.05 ) is drastically different from the air turning into the branch ( C = 1.2 ). The ASHRAE DB requires you to specify (which leg is which). Always double-check the database diagram before applying the number.
The ASHRAE Duct Fitting Database (DFDB) is an essential digital resource for HVAC professionals, providing standardized pressure loss data for over 240 types of duct fittings. Developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, this database helps engineers and designers accurately calculate the External Static Pressure (ESP) of duct systems, ensuring that air distribution is both efficient and energy-conscious. Ashrae Duct Fitting Database
The ASHRAE Duct Fitting Database offers numerous benefits to HVAC engineers, including: In a tee or junction, the loss coefficient
Let’s walk through a practical scenario. You are designing a 90-degree rectangular elbow with turning vanes. The ASHRAE Duct Fitting Database (DFDB) is an
The 2022 version of ASHRAE Standard 90.1 ("Energy Standard for Buildings Except Low-Rise Residential Buildings") has strict mandatory provisions regarding duct design. Section 6.5.3.2 requires that duct systems be designed to have static pressure no greater than the value used in fan energy calculations.