[Noise in vocational schools. Causes of occurrence and assessment of exposure to schoolchildren].

Acoustic conditions in the classrooms of vocational schools are comparable with those in high schools. However, much worse acoustic conditions are observed in vocational school workshop. The evaluation of acoustic conditions in 712 school shops showed, that noise exposure of schoolchildren is very various and depends upon type of workshop and tasks performed by schoolchildren. The major source of noise exposure is machinery in mechanic workshops (plastic working--up to 105 dB, machine noise-from 80 to 90 dB), in textile workshops--from 90 to 100 dB and woodworking machines-from 92 to 102 dB. It should be noted that in such acoustic conditions schoolchildren stay for a relatively long time. Average exposure time of schoolchildren in mechanic or textile workshops was about 4.5 hours. At another training subjects i.e. electric, building, welding craft or gastronomy--noise exposure is usually below recommended standards (80 dB). The critical values accepted for hearing protection for occupational exposure (85 dB) were exceeded at 10% investigated training places of schoolchildren. This mostly occurred in mechanic workshops. Taking into account increased sensitivity of young people it would be worthwhile to work out separate criteria in this range for school workshops. Tentatively, problem should be solved by shortening exposure time depending on actual noise level.