Protect your hearing so you can enjoy the sounds you love

Introduction

Do you know what level of protection your employees are receiving from their hearing protectors? Now you can with a field attenuation estimation system (FAES). FAES is a quantitative method for individual fit-testing hearing protection devices (l—lPDs). This white paper describes the 3M™ E-A-Rfit™ Dual-Ear Validation System and the value it can provide for your hearing loss hearing conservation program (HCP).

The Technology The 3M™ E-A-Rfit™ Dual-Ear Validation System is based on field microphone-in-real ear (F-MIRE) technology. The system consists of a specially designed loudspeaker equipped with a digital signal
processor that allows for a consistent presentation of the test signal and real-time communication
between the microphones, speaker and software. Specially designed, dual element microphones
make it possible to measure the sound level at 2 different locations and for both ears simultaneously.
The external microphones measure the level of the test signal outside the ear. The internal
microphones are connected to one of the specially modified SM“ probed hearing protectors to
allow measurement of the sound level inside the wearer’s ear canal while the hearing protector is
worn. The 3M™ E-A-Rfit™ Dual Ear Validation System also has earmuff testing capabilities. Both ears
are accurately measured simultaneously, and in less than 5 seconds, a personal attenuation rating
(PAR) is displayed.

It starts with Personal Attenuation Rating (PAR) 

The measurement of attenuation for a fit-tested hearing protector is displayed as a PAR. To be sure that your employees are getting the protection they need, you should to know the PAR of every employee. Hearing protector ratings such as the noise reduction rating (NRR), the single number rating (SNR) and the sound level conversion are derived from measurements gathered in a carefully controlled laboratory environment. Although the ratings are an accurate measurement of the capabilities of a particular hearing protector under the specific test conditions, they may not represent what an individual worker will achieve when the device is worn. l\/lost employees receive adequate protection, while some may not if they are not using the hearing protector correctly or have not chosen the correct size or style (Figure l). Note the wide range of PAR values tested on four (4) earplugs considered high attenuating according to their labeled values.