Sound levels of signals presented through headphones are usually measured by artificial ears. This unit corresponds well with the physiological sensitivity of human and it has been generally adopted in scientific literature. The fundamental unit of noise exposure measurement is A-weighted decibel. Noise exposures and sound exposures at high sound pressure level may result in similar damage to hearing. The word “sound” is used consequently throughout this opinion to clarify that the concern is the voluntary listener of personal music players and not the observer of the listening situation. Table 3: Protection action levels according to EU DirectiveĪlthough the above regulations and limits apply to the workplace, the fact that they rely on the exposure level and duration means that they can equally be applied to other situations where sound has a detrimental effect such as that from personal music players whether use in workplace, or under leisure situations.įor the purposes of this mandate “ noise” has been defined as any unwanted sound. Thus, listening to a PMP player at 95 dB(A) for 15 minutes a day would equate to the first action level, under the assumption of this exposure repeated over a long period. If these values are converted using the time-intensity trade-off of 3 dB increase for halving the time then the equivalent levels are shown, for example in a night club with sounds of 104 dB(A) 2 minutes of exposure is equivalent to 80 dB(A) L equ, 8h. Noise at Work Regulations (Directive 2003/10/EC, came into force in 2006) recommend three action levels for occupational settings depending on equivalent noise level for 8-hour working day. Therefore, the new EC Directive on the minimum health and safety requirements regarding exposure of workers to the risks arising from physical agents (noise) introduces lower exposure action value at L equ, 8h = 80 dB(A) (Directive 2003/10/EC). However, this limit did not guarantee the safety for the auditory system of workers. International standards (ISO 1999:1990 NIOSH revised criteria, 1998) recommended the equivalent sound pressure level ( L equ, 8h) of 85 dB(A) (A filter-weighted, 8-hour working day-weighted average) as the exposure limit for occupational noise (ISO 1999:1990 NIOSH revised criteria, 1974). workplace) exposure, the level of 85 dB(A) was regarded as the critical intensity at exposures below 85 dB(A) the hearing losses were significantly lower than for exposures exceeding this value (Welleschik 1979). Time duration calculations were derived from NIOSH MATLAB based modeling.For long term (e.g. *Sound source levels were abstracted from the Noise Navigator TM Sound Level Database (Univ. 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. 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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