EVS-EN 24869-3:1999

The Technical Report specifies a method for measuring the insertion loss of ear-muff type hearing protectors for quality inspection purposes. The method may also be used to investigate production spreads of performance as part of type approval or certification procedures and to investigate the change of performance with age.  A measurement of application force is specified because the force affects acoustic performance.  The method specified in this Technical Report is not intended to be used as the basic test for type approval purposes. Performance data obtained by this method are not to be quoted as representing the real-ear sound attenuation of an ear-muff, nor the protection provided by the ear-muff.  Note 1: A further application of the method is its use to ensure that ear-muff hearing protector samples submitted for subjective testing of attenuation according to ISO 4869-1 have performance typical of the type.  Note 2: For the testing of certain ear-muffs such as those attached to safety helmets, or those with contoured ear-cups or ear-cushions, the procedure described in this Technical Report may have to be slightly modified.