Introduction: The most common standards being used for predicting the health risks of whole body vibrations are ISO 2631- and BS 6844, presenting frequency weighting anfd different coefficients for different sensivities in variuse axes. In yhis study, vibration was measured about 900 minutes on 9 trains in one of the active lines of tehran metro with the aim of comparing the mentioned standards in evaluating whole body vibation.

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Material and Method: In this research, in addition to evaluation of different kinds of vibration indicators, the differences of ISO 26331-1 and BS 6841 Standards have also been investigated. The amounts of r.m.s., vibration dose and daily vibration dose were measured in x, y and z axes for drivers seat and x axis for drivers back rest separately according to the instruction of the two standards.

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Result: The mean calculated values of r.m.s and vibration dose on a basis of 135 6841 standard were lower than those values calculated according to ISO 2631 standard. Moreover, the results showed that 3 cases, based on the ISO standard, had risk level of higher than 17 m/s1.75 and 3 cases, had risk level of higher than 15 m/s1.75 value, provided by BS 6841.

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Conclusion: Calculation according to the ISO 2631-1 standard show higher values. Indeed, ISO 2631-1 can provide a more secure criterion company to BS 6841, although the 15 m/s1.75 in BS is lower than the highest level of health guidance caution zone in ISO. Additionally, the association between r.m.s and vibration dose values in ISO 2631 is relatively lower than this association in BS 6841.