On-Line Catalog : Rectangular Silencers > SF > SF-94
Model SF-94 Standard Frequency Silencer
All acoustical performance and aerodynamic data is derived from laboratory tests in accordance with ASTM E477-99, the standard method for testing duct silencers. Published information originated from a 24" x 24" (610 x 610mm) production unit, tested in forward flow (+, air/noise in same direction) and reverse flow (-, air/noise in opposite directions). If silencers are installed immediately before or after elbows, transitions, at the intake or discharge of the system or without a duct, allowance for such conditions must be included and compensated for when calculating the operating pressure through the silencer. Failure to make allowances for these conditions can add several velocity heads to the pressure loss of the system.