Category: (((—Acoustics Engineering—))))

Many governments require or mandate hearing conservation programs for workers in industries and in other occupations in which hazardous noise conditions exist. Hearing conservation programs are designed to protect workers from the effects of hazardous noise environments. Most nations have dictated specific obligations at an action level which corresponds to a dose of 50% of…

Hearing Protectors It is best practice to reduce noise through: (i) the use of passive engineering controls such as use of enclosures, sound‐absorbing materials, barriers, vibration isolators, etc. and then (ii) using administrative measures such as restricting the exposure of personnel by limiting duration, proximity to noise sources, and the like. In cases where it…

Noise dose (D) is a measure of the exposure to noise to which a person is subjected. It is defined in terms of the A‐weighted sound pressure level eight‐hour limit (PEL) that represents a 100% dose. For a given duration of the exposure to noise at the constant A‐weighted sound pressure level (C) in hours,…

According to studies carried out on workers exposed to A‐weighted noise levels over 85 dB in the U.S. [26], the types of occupations that present the highest risk for hearing damage in terms of numbers of workers overexposed are: manufacturing and utilities, transportation, military, construction, agriculture, and mining. In 1981, the Occupational Safety and Health Administration (OSHA) estimated…

High levels of impulsive and impact noise pose special threats to human hearing. These types of noise can also be very annoying. It is well known now that high levels of such noise damage the cochlea and its hair cells through mechanical processes. Unfortunately, there is currently no commonly accepted definition or recognized standard for…

Since World War II, a considerable amount of information has been gathered on hearing loss connected with intense noise. Most of these data have been collected in industry, but there have been other sources (e.g. aircraft pilots and military personnel). Because in most instances the data have been collected for individuals working eight‐hour days, little…

If very intense noise levels of the order of 135 dB or above at any frequency in the hearing range are experienced, immediate hearing damage is likely to result. However, permanent hearing damage is also produced at much lower sound pressure levels if the noise is experienced over much longer periods (weeks, months, or years). This…

So far we have described the disturbing effects that are produced by noise within the frequency range of human hearing from about 20 to 16 000 Hz. But noise above and below this frequency range can also disturb people. Very low frequency noise or infrasound (usually considered to be at frequencies below 20 Hz) may be very intense although “inaudible”…

Several reviews have been written on the possible effects of noise on the performance and efficiency of people at work. Broadbent [13] worked on this topic for many years and has concluded that many investigations both in the laboratory and industry on the effect of noise on mental or motor performance have been inconclusive. Kryter…

It has been established through laboratory, field and animal experiments that there is a relationship between exposure to noise and cardiovascular diseases, such as ischemic heart disease and hypertension. In particular, a number of studies have shown that exposure to intense noise affects the sympathetic and endocrine system increasing heart rate, blood pressure, peripheral vasoconstriction,…