Effects of hearing protection field attenuation estimation systems and associated training on the level of noise attenuation in workers exposed to noise

Abstract Standardised measurements of sound attenuation of hearing protectors are performed in the frequency range from 125 Hz to 8 kHz. However, noise present at many workplaces contains significant components at higher audible frequency. Therefore, the knowledge about noise attenuation with earmuffs in the audible frequency range above 8 kHz is also necessary for proper hearing protection. The aim of this study was to obtain values of the noise attenuation with 27 commonly-used earmuffs models in the 1/3 octave bands of 10, 12.5 and 16 kHz. The measurements were conducted with a real ear at threshold (REAT) method with participation of subjects. The study showed that attenuation of earmuffs ranged from 24.7 to 42.8 dB, depending on model of earmuffs and frequency band. Furthermore, the measurements were performed with the use of acoustic test fixture which is designed especially for testing hearing protectors. Results obtained with the use of acoustic test fixture indicated that this measurement method can lead to values close to attenuation measured with participation of subjects. On the other hand, values obtained with the use of acoustic test fixture may differ average up to 14 dB from REAT method.

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The effect of hearing protection devices on speech intelligibility of Persian employees

BMC Research Notes ◽

10.1186/s13104-020-05374-x ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Mina Karami ◽

Mohsen Aliabadi ◽

Rostam Golmohammadi ◽

Morteza Hamidi Nahrani

Keyword(s):

Noise Reduction ◽

Speech Intelligibility ◽

Work Environments ◽

Hearing Protection ◽

Noise Attenuation ◽

Speech Discrimination ◽

Significant Difference ◽

Protection Devices ◽

Male Subjects ◽

Speech Interference

Abstract Objective This study aimed to investigate the effect of hearing protection devices (HPDs) on speech intelligibility in Persian work environments. Three current earmuffs and three earplugs and one of the prototypes of molded earplug were tested on 15 male subjects which were randomly selected. The noise reduction of HPDs was measured based on the Real Ear Attenuation at Threshold (REAT) method. Speech intelligibility during using HPDs was determined based on the speech discrimination score (SDS) at two signal to noise (S/N) ratios (0 and + 5). Data were analyzed using SPSS 22. Results The actual to nominal noise reduction rating values were from 47 to 84% for HPDs. At two S/N ratios, no significant differences were observed in speech intelligibility using HPDs (p > 0.05). At S/N ratio = 0, the speech intelligibility descriptively has been only improved by using common earmuffs up to 9.07%. There was a significant difference up to 21.27% in speech intelligibility for proposed molded earplugs at S/N ratio = 0 (p < 0.05). Increasing the HPDs' noise attenuation values led to an increase in speech interference (p < 0.05). The HPDs with the minimum required noise attenuation while maintaining acceptable speech intelligibility should be worn by employees exposed to medium noise levels.

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Protection by noise in quarrying activities: test methods comparison of the hearing protection devices efficiency

E3S Web of Conferences ◽

10.1051/e3sconf/201912808005 ◽

2019 ◽

Vol 128 ◽

pp. 08005

Author(s):

Guido Alfaro Degan ◽

Gianluca Coltrinari ◽

Dario Lippiello ◽

Pietro Nataletti ◽

Diego Annesi

Keyword(s):

Test Methods ◽

Hearing Protection ◽

Noise Attenuation ◽

Specific Procedure ◽

Negative Effects ◽

Relevant Role ◽

Measurement Methodology ◽

Protection Devices ◽

Maximum Protection

The work operations in the quarry activities are the source of many physical agents such as dust and vibrations but especially noise. This last can have relevant negative effects they cause serious problems for the worker’s health. In order to prevent the hearing loss, the employer must provide to the workers the HPD (Hearing Protection Devices). They are inserted inside the ear following a specific procedure to ensure the maximum protection by the noise. For this reason, the use training represents an essential aspect. Also the material, which the device is made of, can influence strongly the actual noise attenuation. The study is based on tests with different HPD, some made of polyurethane and others by silicone. Two experimental campaigns were carried out under different conditions with the same measurement methodology. The results highlight the importance of the methodology used in the test and the relevant role of the use training.

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