[Experimental measurement of the real reduction (PAR) of seven ear plugs]

The study aimed to evaluate, through the use of the EA-RfitTM Validation System, the real reduction (PAR) for the right ear (AuD), for the left ear (AuS) and biaural reduction related to each of the seven earplugs currently produced by 3M. In addition, we wanted to verify any difference between the aforementioned PARs in consideration of the tendency to predominantly use the right hand (right-handed) or the left hand (left-handed) and in relation to gender. Finally, for each insert and for each subject, an audiometric examination was conducted with the insert worn, to compare the average PAR value obtained by the EA-RfitTM system for each of the seven inserts and for all selected subjects, with the determined abatement curve through the audiometric measurement of the hearing threshold with the insert worn. The use of the E-ARfitTM system for the choice of the ear insert leads to important advantages in the protection of all workers. Moldable acoustic PPE generally proved to be more efficient than non-moldable, so much so that the higher SNRs (provided by the manufacturer), especially when referring to non-moldable inserts, were found to be misleading as to the real personal abatement capacity of the inserts. The average audiometric curves, obtained with the different inserts worn, confirmed that all of them guarantee a higher reduction for high frequencies than for "social" ones.