Additionally, you need to consider how long you’ll be exposed to dangerous levels of sound. decibel (dB), unit for expressing the ratio between two physical quantities, usually amounts of acoustic or electric power, or for measuring the relative loudness of sounds.One decibel (0.1 bel) equals 10 times the common logarithm of the power ratio. Check the volume of the gunshots you’ll be exposed to in the section below and subtract 120 dB to determine how much noise reduction you’ll need. Time duration calculations were derived from NIOSH MATLAB based modeling. To prevent instant damage from a gunshot, you’ll need to reduce the sound to less than 120 dB. Thats why sounds high up the decibel scale (from about 85200dB) are a major cause for concern: the sound waves carry so much energy that they will damage your hearing, sooner or later. *Sound source levels were abstracted from the Noise Navigator TM Sound Level Database (Univ. A decibel is a logarithmic scale describing the degree of loudness for a sound. A sound of 100dB is actually 1,000,000,000 times more intense than a sound of 10dB and not 10 times as intense, as you might suppose. Therefore, a 10 dB sound is 10 times more intense than a 0 dB sound, a 20 dB sound is 100 times more intense, and a 30 dB sound is 1,000 times more intense. Yes, if the reference level used for decibel scale is above threshold of hearing. However, the decibel scale is logarithmic, not linear. According to the chart, a 60 dB sound has an intensity that’s one thousand times that of the 30 dB sound (1,000,000 pW/m 2 compared to 1,000 pW/m 2). In addition, exposure to impulse noise (abrupt high intensity sounds of short duration ) should never exceed a peak sound pressure of 140 dB peak in adults, and 120 dB in children. Sound level is not the same thing as sound intensity. In 1999, the World Health Organization Guidelines for Community Noise concluded that a 24-hour equivalent sound level of 70 dB or below would be expected to avoid hearing impairment in 95% of people, even over a lifetime exposure. To protect the public health and welfare, in 1974 the Environmental Protection Agency determined a 24-hour exposure limit level of 70 dB would produce minimal hearing loss.
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