David Clark H3310 Quick Start Manual

David Clark H3310 Quick Start Manual Manual pdf 1 page image

19500P-88 (11-15) 2015 David Clark Company IncorporatedUSE AND CARE INFORMATIONThe effectiveness of a hearing protector in reducing noise is known as its "attenuation". Attenuation is measured in decibels (dB). Federal law requires astandardized method of measuring and summarizing a hearing protector's noise attenuation, known as the Noise Reduction Rating (NRR).The following information can be obtained from the NRR:1. A hearing protector with a higher NRR than another model hearing protector is likely to give the wearermore protection. For example, if hearing protector A has an NRR of 25 and hearing protector B has anNRR of 21, hearing protector A will give most users 4 dB more protection than hearing protector B.2. The noise level (dB) to which you are exposed while wearing a hearing protector can be estimated bysubtracting the NRR from the measured work place noise level. For instance, if the work place noiselevel is measured to be 100 dB and a hearing protector with an NRR of 21 is properly worn, most userswould experience a noise level no greater than 79 dB while wearing the hearing protector (100 - 21=79).Federal law requires the following statement concerning use of the NRR:"The level of noise entering a person's ear, when a hearing protector is worn as directed, is closely approximated by the difference between the A -weighted environmental noise level and the NRR.EXAMPLE: 1. The environmental noise level as measured at the ear is 92 dBA.2. The NRR is 17 decibels (dB).3. The level of noise entering the ear is approximately equal to 75 dBA.CAUTION: For noise environments dominated by frequencies below 500 Hz the C -weighted environmental noise level should be used."MODEL(S) H3310ATTENUATION CHARACTERISTICSFrequency (Hz) 125 250 500 1000 2000 3000 4000 6000 8000Attenuation (dB) 22.4 25.5 30.3 33.3 34.1 39.3 39.9 38.7 38.3Standard Deviation 3.2 3.2 3.0 2.2 2.5 2.6 2.4 2.5 3.5CAUTIONS:1. Limitations on Effectiveness of NRRThe NRR is required by federal law and may not be an accurate indicator of afforded protection for your particular use. The use of a hearing protectordevice, regardless of the NRR, will not guaranty adequate protection from hearing loss for all people under all possible circumstances. Consult yourphysician frequently when being exposed to high noise levels. If exposure to high noise levels occurs during employment, consult with your employerregularly as well.The NRR does not address other important factors such as durability, suitability for the work environment, maintenance, or wearer comfort; therefore,NRR should not be the only reason for choosing the most appropriate hearing protector for the work environment.The hearing protector should provide the necessary attenuation at the specific frequencies prevailing, which the NRR does not take into consideration,i.e., a hearing protector with a high NRR may attenuate poorly at the frequencies in your work environment.

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