ارزيابي ميزان صدا و اثرات آن در يك كارخانه ساخت قطعات اتومبيل

The Operation of Industries results in high levels of noise. These may have severe adverse effects to workers. Here we look at the noise levels and impacts associated with the operation of an automobile part manufacturing company. 400 workers with mean age 28 years-old and work duration ranged 1-3 years engaged in 8 workshops. A total of 139 sound measurements were made at all workshops. 35 stations of them were also analyzed at octave band frequencies separately (again). 11 workers in material grinding, ultrasonic and forging workshops were exposed to 112.1, 104.8 and 86.1 leq dBA (8) respectively. Mean sound pressure levels at the other workshops were under the standard level for an 8 hours exposure (85 dBA). 50 out of 400 workers and 15 out of 85 non-exposed officials as a control group were examined for noise-induced hearing losses. The audiograms of 11 workers who engaged in high level noise workshops showed 8% hearing toss more than those for the control group. The observed hearing losses have occurred mainly in the lower frequencies and there was no significant difference between two groups for losses at the 4000Hz frequency. Workers at the material grinding and ultrasonic workshops always wear earplug with earmuff simultaneously but the rest did not use any personal protective equipment. The interference of sound levels to the speech was assessed at all workshops for times the noisy machines have been working. Noise at the material-grinding workshop prevents any conversation between workers. Speaking in ultrasonic and forging workshops was only possible by very loud speaking from 1-meter distance. There was no major problem to speaking in the other workshops.