BPH 280 WHEEL PERFORMANCE CURVE volume flow rate V [m³/h] FAN SIZE "K" factor correction for spectrum noise of BPH Octave band (Hz) 63 125 250 500 1K 2K 4K 8K inlet -4 -5 -2 -5 -8 -11 -15 -20 BPH 280 outlet -2 -3 0 -3 -4 -8 -11 -16 15