Acoustics. Determination of sound power radiated into a duct by fans and other air-moving devices. In-duct method subscription-only BS IEC TR 62157 is

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Acoustics. Determination of sound power radiated into a duct by fans and other air-moving devices. In-duct method subscription-only BS IEC TR 62157 is1 Scope 1. 1 General This International Standard specifies a method for testing ducted fans and other air moving devices to determine the sound power radiated into an anechoically terminated duct on the inlet and or outlet side of the equipment. NOTE 1 For the sake of brevity, wherever the term fan occurs in the text, it means fan or other air moving device. The method is applicable to fans which emit steady, broad band, narrow band and discrete