Vibration Monitoring: What kind of equipment is used?

Seismographs are instruments used to measure the amplitude, frequency and duration of vibrations caused by construction, engineering, and other equipment vibrations. A variety of vibration sources can be measured to determine the amplitude in velocity (inches/second) and the frequency (Hz) of the movement, typically in the soil close to a structure of concern. In a majority of cases, the vibration levels are measured to ensure that a particular structure of concern is not being damaged by the vibration source. The typical industrial seismograph measure 3 components of motion, longitudinal or parallel to (towards) the vibration source, transverse or perpendicular to the vibration source and vertical which is up and down. Depending on the vibration source, we may also want to measure air overpressure using a linear microphone.

Each of the components of motion is measured by a magnetic coil sensor that measures the speed or velocity of the axis motion, as well as the frequency of change of the velocity. These two values are typically used to calculate damage criteria for a structure following a specification set out for the particular project the seismograph is being used for. Measurements are made at pre-determined sample rates set on the seismograph with pre-set recording modes and times. Data from the seismograph can then be downloaded to a computer for further analysis and report preparation.

Most specifications such as USBM RI-8507 are written using velocity and frequency criteria for vibration measurement.

Contact John V. Dinan Associates if you are in need of Vibration Monitoring Plans, Manual Vibration Monitoring or Automatic Vibration Monitoring.