Since damper authority affects the installed characteristic curve of an ideal duct-damper path, which has a controlled differential static pressure between its two connected nodes, in order to obtain an approximate linear installed characteristic curve, a parallel-blade damper is preferred for the paths with high damper authority and an opposed-blade damper
is preferred for the paths with low damper authority (ASHRAE 2010c; Lizardos and Elovitz 2000).
(304 mm) opposed-blade damper. This section introduces the experimental setup and the test matrix for the determination of damper and housing characteristics.
Empirical Parameter for Primary Airflow Model with Opposed-Blade Damper Damper OB8 ([R.sup.2] = 0.990) OB12 ([R.sup.2] = 0.926) Angle [a.sub.1] [b.sub.1] [a.sub.1] [b.sub.1] 0[degrees] to -14.186 0.0141 -14.976 -0.0527 4.5[degrees] 4.5[degrees] to -14.187 0.0423 -14.815 0.0393 27[degrees] 27[degrees] to -14.989 0.0724 -15.817 0.0704 40.5[degrees] Table 5.