ISO/TR 18570:2017 pdf download – Mechanical vibration — Measurement and evaluation of human exposure to hand transmitted vibration — Supplementary method for assessing risk of vascular disorders.
4 Characterization of hand-transmitted vibration 4.1 General considerations The method specified in this document takes account of the following factors which are believed to influence the vascular effects of human exposure to hand-transmitted vibration in working conditions: a) the frequency spectrum of vibration; b) the magnitude of vibration; c) the duration of exposure per working day. Other factors which may influence the effects of vibration exposure, but for which standardized methods for reporting do not yet exist, are listed in ISO 5349-1:2001, Annex D. 4.2 Measuring equipment for hand-transmitted vibration 4.2.1 General Measurement of hand-transmitted vibration should be undertaken using instrumentation conforming as far as is possible to the requirements of ISO 8041-1. This equipment should be checked for correct operation before and after use. The calibration should be traceable to a recognized standard maintained by an accredited laboratory. ISO 8041-1:2017 does not provide specifications for the W p frequency weighting. Where possible, measurement equipment should conform to the basic requirements of ISO 8041-1. 4.2.2 Vibration transducers The vibration transducer requirements should be the same as those specified in ISO 5349-1:2001, 4.2.2. 4.2.3 Location and orientation of transducers The location and orientation of vibration transducers should be the same as those specified in ISO 5349-1:2001, 4.2.3. 4.2.4 Mounting of transducers The mounting requirements for vibration transducers should be the same as those specified in ISO 5349-1:2001, 4.2.4. NOTE The consequence of poor mounting may be more noticeable with W p than with W h .
A frequency weighting is required to quantify the risk of developing symptoms of vibration white finger (VWF) from exposing the hands to vibration. The frequency weighting accounts for the relative hazard posed by vibration at different frequencies. Predictions of risk using the procedures described in annexes to ISO 5349:1986 and ISO 5349-1:2001 have been found to agree with the observed latencies of finger blanching (i.e. the years of exposure to vibration prior to the appearance of the first white finger) for some occupationally-exposed population groups, as well as to underestimate or overestimate the risk for some situations. [1],[2] The risk of developing VWF is overestimated for power tools such as rock drills, pavement breakers and sand rammers, and underestimated for riveting tools. [1–7] The discrepancies between predictions of the risk of developing VWF and the experience of population groups occupationally exposed to vibration have been attributed, in part, to the frequency weighting recommended in ISO 5349-1. Frequency weightings can be derived, in principle, from physiological or patho-physiological responses to vibration in humans or animals, from biodynamic models characterizing vibration entering the hand- arm system, or from epidemiological studies of population groups in which vibration exposures have been measured or can be estimated. Attempts to construct frequencies weightings from physiological responses of humans or animals, while informative, have not so far proved to be definitive. Most information on the form of frequency weighting necessary to characterize the development of VWF has come from biodynamic models contained in ISO 10068:2012, and from analyses of epidemiological studies using trial frequency weightings. [8–12]