[215] Oil analysis versus oil-based condition monitoring – what to expect and, more importantly, what not to expect

D C Shorten

Optimain Limited, Frome, Somerset BA11 3AR, UK. 
Tel: 44 (0)7866 266515; Email: dcs@optimain.co.uk; Web: www.optimain.co.uk 

Oil analysis (OA) and oil-based condition monitoring (OBCM) are two very different and distinct things, based upon the results of filed and laboratory testing of lubricants, and have very different intended outcomes. OA is usually provided to look at the condition of the oil itself in order to determine whether the oil is fit for further service, while OBCM is primarily concerned with the condition of the machinery in which the oil is serving. As practitioners of failure analysis, we are often provided with historical oil test data as a means to add value to our investigations. We find, however, that such reports are often meaningless and of no real value to failure analysis as they are neither forensic evidence from the scene of failure nor are they sufficiently detailed to add anything more than a cursory view of whether anything obvious was missed when the system was operating normally. This short paper will seek to stimulate discussion in regard to the significant differences between checking the condition of the oil and using the oil to determine the condition of its parent plant. This is especially relevant where the reported data is being used as part of an operational activity, such as failure loss adjustment, or for added assurances and intelligence where scheduled maintenance activities are being deferred.
The author, who has direct experience of the provision of both OA and OBCM, will illustrate the common misconceptions and the pitfalls that can be encountered by users of oil analysis techniques and in addition he will seek to stimulate discussion regarding the best way for industry to move forward in order to realise savings in terms of increased safety due to improved asset reliability and towards the reduction in the frequency and types of component failure experienced.