Evaluation of exposure of metro passengers to whole-body vibration and recurrent shocks according to ISO 2631- 1 standard

Nowadays, using rail vehicles like metro is necessary for transportation in megacities and metropolises. In this descriptive-analytical study, whole body vibration was evaluated by two methods including basic evaluation and the recommended dose of vibration proposed based on ISO 2631-1 standard. In the present study measurements were performed over 13000 seconds in usual daily working hours by using SVAN 958 apparatus manufactured by Svantek Company, while the wagons were in motion at average speed. Tri-axial effective acceleration values were determined on the passengers contact surfaces and on the wagon seats in the different lines of Tehran metro. The results of evaluation based on the basic method showed that evaluated levels for 60 and 150 minutes of exposure calculated by an equation with higher safety according to ISO standard showed that all of samples except one were in the Health Guide Critical Zone (HGCZ). Based on Vibration Dose Value (VDV) method, except for two cases in each group of the exposure periods which were in the HGCZ of ISO, all the other cases had low risk levels of exposure. The findings of both the methods indicated that, different evaluation methods may gain different outcomes. It seems that the recommended safety levels in VDV method seriously need to be corrected. In addition, considering average exposure levels gained in this study, it is recommended to apply appropriate control measures for declining exposure amount of passengers.