Steps should be taken to limit the transmission and increase the absorption of noise.
Additional Information: Noise can be reduced by increasing the distance of the noise source from the worker. This technique is less effective for low frequencies. Sound-attenuating barriers or enclosures should be used when workers are required to work near equipment that, despite quieting measures, produces high levels of noise. Wherever possible, these barriers should be rated by STC according to ASTM E90 (2009). See Guideline 12.1.2.5-5 under “Noise Distractions” above for more information. In addition, sound-absorbing materials should be applied to surfaces to reduce the level of noise in enclosures. Such materials can absorb over 70 percent of the noise that strikes them. These materials are effective for both low and high frequencies. Wherever possible, the sound-absorbing properties of materials should be measured by their Noise Reduction Coefficient according to ASTM C423a (2009). See Guideline 12.1.2.5-6 under “Reverberation Time and Sound Absorption” above for more information.
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