Some issues in fan noise calculation

Points out some mistakes existing in the HVAC fan noise sound power calculation formulas and related datum tables. Explains the difference between specific sound power level and the specific A-weighted sound power level. Under the present conditions, proposes to adopt the measured values of sound power level of fans given by the fan manufacturer in noise elimination calculation for air conditioning. If the manufacturers could offer the measured values of sound power level of inlet, outlet and outside of the AHU in a reverberation chamber, the noise elimination calculation results would better meet the needs of practice.