Modification of the ISO-10816 centrifugal pump vibration severity charts for use with octave band spectral measurements

Abstract

The ISO standard 10816 gives acceptance levels of vibration for centrifugal pumps in the form of a severity Chart. The measured 10-1000 Hz RMS velocity vibration of pumps within a given size and physical setup can be judged against the severity chart limits to give an indication of the pumps running health. This single RMS velocity value, although having being shown to be a reasonably robust measurement tool for analysing the condition of a centrifugal pump, does not allow discrimination between failure types resulting in the increased vibration, and indeed overlooks the subtleties of the pump condition state. This limitation in the use of general RMS velocity vibration levels for use with rotating machinery health is well documented, and a vast number of more sophisticated techniques, to pin point faults in specific machinery, have been developed. These techniques, although powerful, often require detailed information, such as the number of balls in a specific bearing within the machine. This information is often not readily available for a given pump setup. Tailoring these sophisticated vibration diagnostic tools for a specific pump setup can require a considerable amount of man hours and expertise, therefore having general vibration diagnostic tools which don’t require extensive data about the particular pump setup would be ideal. It is proposed in this paper that the use of Octave band spectral measurements of pump vibration can strike a better balance between the two extremes of vibration analysis being: (i) overall RMS vibration velocity levels, (ii) highly specific analysis techniques such as envelope analysis for bearing fault detection.The use of Octave band spectral measurements still allows broad employment in centrifugal pump setups without a high degree of specific setup details being required. Within this paper modification of the ISO-10816 severity charts for use with Octave frequency band measurements is presented. With the use of some in-field vibration measurements, initial justification and validation of the modified vibration severity levels is presented.