Measurement of vibration of hand-held tools: weighted or unweighted?

The standards for hand-arm vibration have evolved from research studies in the late 1960s and were based on discomfort and tolerance levels. The lower frequencies were more intolerant and were weighted accordingly. The vascular and neurologic components of the hand-arm vibration syndrome may develop independently, and recent epidemiologic studies have shown both underestimation and overestimation in the incidence of Raynaud's phenomenon from the International Standard Organization dose-response criteria with respect to different tools. The validity of the current International Standard Organization, British Standards Institute, American National Standards Institute, and The American Conference of Governmental Industrial Hygienists Threshold Limit Values is therefore questionable. The weighted and unweighted frequency spectra of various hand-held tools are presented in this paper. It is concluded that, until such time as more dose-effect data become available, unweighted measurements should be determined. Furthermore, the frequencies measured should be extended to 5 kHz.