This paper is based on findings resulting from ASHRAE Research Project RP-1319.

Pressure loss coefficients were determined for the following types of flat oval elbows having various aspect ratios: 5- gore 90° easy bend, mitered 90° easy bend with and without vanes, and mitered 90° hard bend with and without vanes. The tests were performed in accordance with ANSI/ASHRAE Standard 120-1999. Data are presented graphically, and the loss coefficient for each fitting is tabulated. A linear correlation coefficient is calculated for each case.

Units: Dual