IEC 60704-2-13:2011 pdf free download – Household and similar electrical appliances -Test code for the determination ofairborne acoustical noise
Air-extraction range hoods shall be loaded using a pipe connected to a muffler according toFigure 101.The pipe shall be rigid with smooth inner walls and shall have the widest diameteramong those specified by the manufacturer. lf not stated, a standard pipe with the best fittingdiameter shall be used.The muffler shall have an insertion loss as specified in the table ofFigure 101.lt shall have a circular section with the same internal diameter as that of the pipe,a length as specified in Figure 101 and shall not have parts protruding inside that may causeadditional pressure drops. The pipe and the muffler shall also comply with all thespecifications reported in Figure 101 and care shall be taken that they do not radiate noise.
Range hoods with external fan shall be connected to the fan with a pipe and a muffleraccording to Figure 103.The pipe shall be rigid with smooth inner walls and shall have thewidest diameter among those’specified by the manufacturer. If not stated, a standard pipewith the best fitting diameter shall be used.The muffler shall be provided with the appliance.lf the manufacturer did not provide a muffler, the appliance is tested without muffler.
In particular，when connecting the pipe and muffler system to the range hood, care shall betaken that this connection does not transfer any additional structure borne noise.For thispurpose, isolating connecting pieces can be used.
Static forces from the standard exhaust to the range hood shall also be avoided.
NOTE 101 The fastening of the muler should not influence the acoustical field in the test room; for example twowires could be fixed around the muffler and on the ceiling.
Whenever it is possible to choose among two or more exit holes for the pipe connection, theone on the upper side of the range hood, if any, shall be used.
Range hoods designed for connection with more than one pipe at the same time shall beconnected accordingly to the number of pipes required.
7.1.1 Replacement:
For range hoods not intended to be placed against a wall, including built-in appliances,themeasurement surface is a parallelepiped with nine microphone positions, as specified in 7.3.1of lSO 3744 and in Figure 1 of IEC 60704-1. Additional measurement positions may berequired according to 7.3.2 of lSO 3744.The number of microphone positions may also bereduced according to 7.4.2 of lso 3744.
While defining the reference box around the appliance, the loading pipe connected to a rangehood operating in exhausting mode should not be taken into account.
NOTE101 The front of the appliance is directed in the direction of the x-axis. The preferred value of themeasurement distance d is 1 m.
7.1.2 Replacement:
For range hoods intended to be placed against a wall，including built-in appliances，themeasurement surface is a parallelepiped with six microphone positions,as specified in 7.3.1of lSO 3744 and in Figure 2 of iEC 60704-1. Additional measurement positions may berequired according to 7.3.2 of lSO 3744.The number of microphone positions may also bereduced according to 7.4.2 of lSO 3744.
While defining the reference box around the appliance, the loading pipe connected to a rangehood operating in exhausting mode should not be taken into account.
NOTE 101 The x and y axes are located in the vertical reflecting plane, with the x-axis directed vertically upwardsand the front of the appliance directed in the direction of the z-axis. The preferred value of the measurementdistance d is 1 m.