Mirbod S M, Iwata H
Department of Hygiene, Gifu University School of Medicine.
Int Arch Occup Environ Health. 1997;69(6):418-22. doi: 10.1007/s004200050169.
On the basis of data presented in our previous, reports, the current study was undertaken to estimate frequency-weighted hand-arm vibration exposure limits for various daily exposure times. The procedures for the present study were as follows. (1) The prevalence of vibration-induced white finger (VWF) as well as the vibration exposure were investigated in various groups of workers operating hand-held vibrating tools. The vibration magnitude of various tools was measured and the results were presented as the energy-equivalent frequency-weighted root-mean-square (m/s2 rms) acceleration. There was a statistically significant positive correlation between the prevalence of VWF and the measured vibration magnitude (R2 = 0.5, P < 0.05). Hence, it was concluded that in decisions concerning quantitative recommendations for vibration exposure, the prevalence of VWF should be considered. (2) By a careful selection of available publications which contain useful information on duration of vibration exposure of < or = 2 h/day and the occurrence of VWF, a significant correlation between the prevalence of VWF and the vibration magnitude could be observed. The regression equation was estimated as: y = -18.5 + 4.6 (x), R2 = 0.8. On the basis of this equation, it was speculated that the prevalence of VWF in workers using vibrating tools might be restricted to the prevalence of Raynaud's phenomenon in the Japanese general population if the 2-h daily vibration exposure is about 4.5 m/s2 rms. (3) Regarding this speculation, the equation provided in the documentation of ISO 5349 was used and modified as: [alpha h,w)eq,t = (alpha h,w)eq,2(2/t)1/2 (m/s2 rms)] and then the vibration limit values for daily exposure of 1 min to 8 h were calculated. (4) In order to achieve compatibility with standards of other countries, and to formulate an easy method for using the recommended values presented here, the daily exposure time of 8, 4, 2, 1 and 0.5 h were selected. The correspondence vibration magnitudes were in the range 22-9.0 m/s2 rms, and the lower limit (2.2 m/s2 rms) was assumed as the permissible vibration exposure limit for an 8-h working period. The proposed daily vibration limits were then compared with those recommended by other institutions.
根据我们之前报告中呈现的数据，开展了本研究以估算不同每日暴露时间下频率加权的手臂振动暴露限值。本研究的步骤如下。（1）在操作手持振动工具的各类工人群体中，调查了振动性白指（VWF）的患病率以及振动暴露情况。测量了各类工具的振动幅度，并将结果表示为能量等效频率加权均方根（m/s² rms）加速度。VWF患病率与测量的振动幅度之间存在统计学上显著的正相关（R² = 0.5，P < 0.05）。因此，得出结论，在有关振动暴露定量建议的决策中，应考虑VWF的患病率。（2）通过仔细挑选包含每日振动暴露时间≤2小时以及VWF发生情况有用信息的现有出版物，可以观察到VWF患病率与振动幅度之间存在显著相关性。回归方程估计为：y = -18.5 + 4.6（x），R² = 0.8。基于此方程，推测如果每日2小时的振动暴露约为4.5 m/s² rms，使用振动工具的工人中VWF的患病率可能会限制在日本普通人群中雷诺现象的患病率。（3）针对这一推测，采用了ISO 5349文件中提供的方程并修改为：[α（h,w）eq,t = α（h,w）eq,2（2/t）¹/² （m/s² rms）]，然后计算了每日1分钟至8小时暴露的振动限值。（4）为了与其他国家的标准兼容，并制定一种便于使用此处给出的推荐值的方法，选择了8、4、2、1和0.5小时的每日暴露时间。相应的振动幅度范围为22 - 9.0 m/s² rms，下限（2.2 m/s² rms）被假定为8小时工作时段的允许振动暴露限值。然后将提议的每日振动限值与其他机构推荐的限值进行比较。
