3) Predictive Maintenance (Condition Monitoring)

Rather than following a standard schedule, maintenance is carried out when early signs of deterioration of the equipment show it is necessary to avoid imminent problems. Inspection of the equipment to assess its condition may use technology such as:

• Thermography: which is used on cables and switch gear to show up hot spots. This produces an infra-red image of the subject which can be recorded by photograph or computer.
  
  
• Ultrasound: a well established technique for the detection of cracks and weld faults in pressure vessels. It can also be used for monitoring low-speed bearings and uses transducers attached to the subject.
  
  
• Oil Analysis: which involves the examination of lubricating oil (with, for example, an electron microscope) to detect fine particles of metal which may indicate that a bearing is starting to break down.
  
  
• Vibration Analysis: which uses an accelerometer to measure vibration, which is processed and presented in the form of a graph. The graph is integrated and transformed to a spectrum over a frequency range.
  
  
• Monitoring other process parameters: such as pressure, flow, load, wear, etc.,.