For the purposes of this chapter, the following terms are defined as follows:
(a) "Frequency" means the number of oscillations per second of a vibration.
(b) "Impact vibrations" means earth-borne oscillations occurring in discrete pulses at or less than 100 pulses per minute.
(c) "Steady state vibrations" means earth-borne oscillations that are continuous. Discrete pulses that occur more frequently than 100 times per minute shall be considered to be steady state vibrations.
(d) "Three-component measuring system" means a device for recording the intensity of any vibration in three mutually perpendicular directions.