조선업 전동수공구의 진동평가와 진동증후군에 대한 연구

Abstract

The purpose of this study is to investigate the relationship between the acceleration of vibration by the powered hand tools used in the shipbuilding industry and the prevalence of hand-arm vibration syndrome among the shipbuilding workers. The acceleration levels and frequencies of nine powered hand tools were measured using the ISO 5349 method along with the time of exposure to the vibration of the powered hand tools. Medical examinations for 114 workers were also performed using the cold provocation test and those for 51 were caried out using the nerve conduction velocity test. Comparisons were made between the estimated prevalence of hand-arm vibration syndrome from ISO 5349 and the observed values by the medical examinations. The results were as follows. Four hour-energy-equivalent frequency-weighted accelerations were 6.23m/s2 in the grinding job done after welding, 13.39m/s2 in the grinding job done before painting. The mean exposure time while holding powered hand tools was 4.64 hours. Prevalence rates of Raynaud's phenomenon were 12.04% in the grinding after soldering, 42.9% in the grinding before painting measured using the ISO 5349 method. After exposure to vibration for 10.79 years, about a half of the workers in the grinding after welding could were expected to develop Raynaud's Phenomenon. the workers in the grinding before painting, the latency was 5.02 years. The ISO dose-response relationship was significantly correlated neither with observed recovery rates of finger skin temperatures, blood flows nor with values of nerve conduction velocities. A regression model for dose-response relationship was derived from the results.