This part of ISO18312 specifies a method for evaluating the vibration power emitted by machines or pipelines (referred to hereinafter as machines) on to supporting structures to which the machines are connected through vibration isolators. This part of ISO18312 also specifies the method for evaluating the vibration power components emitted in the six degrees of freedom of a Cartesian coordinate system at each joint, i.e. three translations and three rotations. The vibration power is determined by processing the signals from two sets of velocity (or acceleration) transducers mounted at the isolator connection points, one set on the machine side (input) and the other on the foundation side (output). This method is applicable for machines under the assumption that their vibration can be characterized by a stationary random process. The components of emitted vibration power are computed using the cross-spectra of the two sets of velocity in narrow band (or one third-octave) and the dynamic stiffness characteristics of the isolator over the frequency range of interest. The upper frequency limits of this method are established in this part of ISO18312. This part of ISO18312 can be used for: evaluating a machinery system from isolator design concept; obtaining data for preparation of technical requirements for allowable machine vibration power emission; determining appropriate and cost-effective vibration control procedures; solving diagnostics issues.