It is generally accepted that machine failures can be prevented by regular monitoring of machine vibration levels.
Such benefits are highly desirable for offshore production platforms, and the paper presents details of recent field experience which shows quantitatively that regular monitoring not only reduces equipment failure, but that it also increases equipment reliability. The paper also presents some preliminary vibration data for 1st generation North Sea platform equipment, which demonstrates the value of checking vibro-mechanical condition onshore before equipment is installed in the complex dynamic environment of the platform.
One of the most useful NOT techniques to be developed in recent years is that of condition monitoring, and in particular vibration monitoring and analysis of running equipment.
The techniques have been developed mainly by the oil and petrochemical companies, who, because of their requirement for long term continuous operation of machinery, were quick to see the advantages in being able to detect incipient failures in machinery without the need for frequent shutdown and inspection.
Correct application of the techniques has been shown, in the case of onshore installations, to lead to a reduction in the number of machinery breakdowns. This in turn yields considerable cost savings, firstly in the production sector, where unplanned shutdown time due to running equipment failure can be virtually eliminated, and secondly in the maintenance sector where repair costs are reduced because of fewer breakdowns.
Fewer breakdowns particularly in Division 1 areas also means less risk of fire or explosion, which in turn means improved standards of safety. This added benefit from vibration monitoring is rarely ever considered but is of vital importance in the light of present day emphasis on safety standards, e.g. the Health and Safety at Work etc. Act, 1974 (1). All these benefits are of equal, if not greater importance to offshore installations, and operators should be aware of the advantages, both financial and engineering, to be gained from using vibration monitoring.
However, the approach to vibration monitoring in onshore installations is by no means uniform and there is no one single philosophy which can be defined and applied directly to offshore platforms. Even if there were, there are major differences in the dynamic environment offshore which significantly affect the technology.
Acoustic Technology is currently involved in vibration monitoring programmes onshore and also machinery vibration studies for offshore installations. Based on this experience, the, paper develops a rationale for machinery vibration monitoring on offshore platforms.
In a recent survey carried out for a U.K. Government department (2) it. Has been estimated that for industries with a high capital investment in plant and machinery per employee, and a high added value, output per employee, condition monitoring in general and vibration monitoring in particular can save on average about 1% of the total added value output per year. Of this saving, approximately 65% will be output related and 35% will be maintenance related.
