Development of a Unique Passive Hearing Protector with Level-Dependent and Flat Attenuation Characteristics

Allen, Clayton H.; Berger, Elliott H.

doi:10.3397/1.2827760

Cited by 18 publications

(13 citation statements)

References 2 publications

(2 reference statements)

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“…Unlike the foam earplug and electronic earmuff, the LD earplug contains a passive acoustic filter intended to create a level-dependent attenuation by responding nonlinearly to increasing sound pressure level (Hamery and Dancer, 1998). Therefore, the IPIL is expected to increase with increasing impulse level above a transition level of approximately 120 dB (Allen and Berger, 1990), as is seen in the measured results. As measured with the shock tube, IPIL increased from approximately 13 dB (at an impulse peak level of 140 dB), to 21 dB (at 150 dB), to 36 dB (at 168 dB).…”

Section: Resultsmentioning

confidence: 54%

Spectral analysis of hearing protector impulsive insertion loss

Fackler

Berger

Murphy

et al. 2016

International Journal of Audiology

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Objective To characterize the performance of hearing protection devices in impulsive-noise conditions and to compare various protection metrics between impulsive and steady-state noise sources with different characteristics. Design Hearing protectors were measured per the impulsive test methods of ANSI/ASA S12.42-2010. Protectors were measured with impulses generated by both an acoustic shock tube and an AR-15 rifle. The measured data were analyzed for impulse peak insertion loss (IPIL) and impulsive spectral insertion loss (ISIL). These impulsive measurements were compared to insertion loss measured with steady-state noise and with real-ear attenuation at threshold (REAT). Study Sample Tested devices included a foam earplug, a level-dependent earplug, and an electronic sound-restoration earmuff. Results IPIL for a given protector varied between measurements with the two impulse noise sources, but ISIL agreed between the two sources. The level-dependent earplug demonstrated level-dependent effects both in IPIL and ISIL. Steady-state insertion loss and REAT measurements tended to provide a conservative estimate of the impulsively-measured attenuation. Conclusions Measurements of IPIL depend strongly on the source used to measure them, especially for hearing protectors with less attenuation at low frequencies. ISIL provides an alternative measurement of impulse protection and appears to be a more complete description of an HPD’s performance.

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Section: Resultsmentioning

confidence: 54%

Spectral analysis of hearing protector impulsive insertion loss

Fackler

Berger

Murphy

et al. 2016

International Journal of Audiology

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“…), a level-dependent earmuff that uses a valve system to achieve low levels of attenuation in low noise levels, with substantial attenuation in impulsive noise conditions. (47) Although this muff provides somewhat less attenuation in the low frequencies than in the middle and high frequencies, the slope between 500 and 8000 Hz is relatively flat (when worn correctly), which is desirable for speech communication. Other earmuffs without the level-dependent characteristic are currently being marketed for their communication advantages.…”

Section: Potential Solutionsmentioning

confidence: 97%

Construction Noise: Exposure, Effects, and the Potential for Remediation; A Review and Analysis

Suter

2002

AIHA Journal

116

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More than one-half million construction workers are exposed to potentially hazardous levels of noise, yet federal and state Occupational Safety and Health Administration (OSHA) programs provide little incentive to protect them against noise-induced hearing loss. Construction noise regulations lack the specificity of general industry noise regulations. In addition, problems that characterize the construction industry, such as worker mobility and the large proportion of small businesses, make implementing hearing conservation measures more difficult. The apparent severity of exposure depends greatly on the measurement method, with the 3-dB exchange rate almost always showing higher average exposure levels than the 5-dB (OSHA) rule. Construction workers demonstrate hearing threshold levels that generally conform to those expected in manufacturing. The prevalence of hearing protection device (HPD) use among U.S. construction workers is very poor, partly because of perceived difficulties in hearing and understanding speech communication and warning signals. In addition, masking by noise of necessary communication and warning signals is of particular concern in construction, where recent research demonstrated the association between fatalities and the failure to hear reverse alarms. Judicial use of HPDs is of the utmost importance, along with avoiding overattenuation, selecting HPDs with uniform attenuation, and using noise-attenuating communication systems when possible. A successful hearing conservation program in British Columbia can serve as a model for the United States, with a long-standing positive safety culture, a high percentage of HPD use, improvement in average hearing threshold levels over the last decade, and a centralized record-keeping procedure, which helps solve the problem of worker mobility. However, controlling construction noise at the source is the most reliable way to protect worker hearing. U.S. manufacturers and contractors should benefit from the activities of the European Community, where noise control and product labeling in construction has been carried out for more than 20 years.

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“…The attenuation performance of a hearing protector is assumed to be constant throughout the linear acoustic regime, levels below 140 dB SPL re 20 μPa. Above 140 dB SPL, the attenuation exhibits a small increase by a few tenths of a decibel per decibel increase in peak level (Allen & Berger, 1990;Murphy, 2003). For a hearing protector, with a nonlinear orifice and for earmuffs, the attenuation can increase as much as a 0.5 dB/dB at levels of 140 to 170 dB peak SPL (Dancer et al, 1999;Zera & Mlynski, 2007;Berger & Hamery, 2008).…”

mentioning

confidence: 99%

Measurement of impulse peak insertion loss for four hearing protection devices in field conditions

Murphy

Flamme

Meinke

et al. 2011

International Journal of Audiology

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Objective-In 2009, the U.S. Environmental Protection Agency (EPA) proposed an impulse noise reduction rating (NRR) for hearing protection devices based upon the impulse peak insertion loss (IPIL) methods in the ANSI S12.42-2010 standard. This study tests the ANSI S12.42 methods with a range of hearing protection devices measured in field conditions. Design-The method utilizes an acoustic test fixture and three ranges for impulse levels: 130-134, 148-152, and 166-170 dB peak SPL. For this study, four different models of hearing protectors were tested: Bilsom 707 Impact II electronic earmuff, E·A·R Pod Express, E·A·R Combat Arms version 4, and the Etymotic Research, Inc. Electronic BlastPLG™ EB1.Study sample-Five samples of each protector were fitted on the fixture or inserted in the fixture's ear canal five times for each impulse level. Impulses were generated by a 0.223 caliber rifle.

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Development of a Unique Passive Hearing Protector with Level-Dependent and Flat Attenuation Characteristics

Cited by 18 publications

References 2 publications

Spectral analysis of hearing protector impulsive insertion loss

Spectral analysis of hearing protector impulsive insertion loss

Construction Noise: Exposure, Effects, and the Potential for Remediation; A Review and Analysis

Measurement of impulse peak insertion loss for four hearing protection devices in field conditions

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