In the main body of this recommendation, conditions are defined for measuring and recording whole body vibration of the seated operator of off-highway self-propelled work machines. The specification of instruments, analytic methods, and description of site and operating conditions allows the measurements to be made and reported with an acceptable precision. The procedure includes means of weighting the vibration level at different frequencies as specified in ISO 2631 (Ref. 1). A standard format for reporting spectral data is recommended. The definitions, instruments, and analytic methods also apply to simulated tests for operator vibration as performed in laboratories. This procedure is a measuring method only and is not intended for the evaluation or selection of seating systems.