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A7. With the aid of the information given below, determine the pressure losses of the fitting outlet 2 (AP12) and outlet 3 (AP₁3) if density of air is 1.2 kg/m². (5 Marks) 2 Flow rate (m³/s) 4.8 Duct section 1: (1m (w) x 0.6m (H)) Dect section 2: (Im(w)x0.3m H)) Duct section 3: (0.5m (w) x 0.3m (H)) 3.3 1.5 C₂₂ 0.8 C₁ 1.3 A8. (a) The measured sound pressure level at 1 kHz of a concert hall is 45 dB. With the aid of Figure A8 and Table A8, determine the required in-duct attenuation at 1 kHz for meeting the lower limit of acceptable NC level (3 Marks) requirement. (b) Determine the overall sound power level produced by forward curved centrifugal fan with motor rating and fan static pressure of 1.5 kW and 350 Pa respectively. (2 Marks) Given: L=67 +10 Log P + 10 Log AP, L=40+10 Log V+ 20 Log AP, L-95 +20 Log P + 10 Log V where: P in kW, AP, in Pa and V in m'/s