IEC 60704-2-7:2020 pdf free.Household and similar electrical appliances – Test code for the determination of airborne acoustical noise -Part 2-7: Particular requirements for fans.
Ceiling fans may be hung from a special support instead of from the ceiling.In this case,careshall be taken to ensure that the means of suspension or clamping do not change the soundoutput of the appliance. In order not to restrict the airflow, the distance between the lowestedge of the appliance and the reflecting plane (usually the floor) shall be at least 1,5 m.
Alternatively,ceiling fans can be mounted in the reverse working position on the reflectingplane,providing this does not affect sound radiation.
Replacement:
Partition (wall and window) fans shall be mounted in an opening made either
– in a wall of the special reverberation test room; or
– on the second reflecting plane of the free field over a reflecting plane environment.The height between the centre of the appliance and the floor shall be 1,5 m ± 0,05 m.
ln all cases, care shall be taken to follow the instructions given by the manufacturer and toavoid any structure-borne noise.
Care shall be taken to avoid any restriction of the airflow.
Attention shall be paid to avoid any difference of pressure between the rooms concerned (or atmosphere), in order to avoid an unwanted load on the fan.
This measurement surface shall be used for table,pedestal, louver, tower,bladeless,ceiling bracket and ceiling fans.Table fans are placed on the floor.
This measurement surface shall not be used for wall bracket fans and window fans.
The use of a windscreen is mandatory.
For partition (wall and window) fans and wall-mounted table fans, the measurement surface is a hemisphere，with 10 microphone positions as specified in Figure 101, centred in the projection of the geometrical centre of the reference box on the vertical plane, the coordinate system describing the microphone positions being located with the x- and y-axes in the vertical reflecting plan and the z-axis horizontally perpendicular to it. The x-axis lies in the horizontal central plane of the reference box.The front of the fan is directed towards the z-axis.IEC 60704-2-7 pdf download.