Evaluation of Whole-Body Vibration Exposure Among Urban Metro Drivers: Comparing ISO2631-1 and ISO2631-5 Standards to Evaluate Exposure

Excessive vibration is one of the harmful agents in the work environment, and many drivers are inevitably exposed to that during driving.
Using ISO 2631-1&5 standards in the present study, the evaluation of the whole-body vibration (WBV) exposure was carried among Tehran metro drivers.
In this descriptive cross-sectional study, 23 trains were investigated and the level of exposure to vibration during daily working shift and vibration indicators were evaluated. According to ISO 2631-1, the following 5 factors were measured: the rate of frequency- weight acceleration r.m.s for each axis, the combination of axes, crest factor, peak acceleration, vibration dose value (VDV), and recent equivalent static compressive stress (Sed) and risk (R) factors - estimation criteria for damage to lumbar spine.
The results indicated that based on the basic method, the levels of drivers exposure to the vibration are less than the lower limit set by health guidance caution zone (HGCZ), and according to the VDV methods, 4 cases were found to be above the upper limit, 8 cases were within the HGCZ, and the rest were less than the mentioned limit. Moreover, according to the Sed method, 4 drivers had exposures below the lower limit, 7 had exposures within the range of HGCZ, and 12 of the mover the limit. On the other hand, on the basis of R factor, the levels of exposure of the 3 drivers were within the range of HGCZ, while the rest of them experienced the levels lower than that.
The results showed that there are several differences among the calculated criteria confirming that some of these indicators may not show a safe limit.