The most important practical issue from our experience is that EXAKT cannot give satisfactory service to a typical maintenance department without the LRCM process implemented. The reason for this is that EXAKT is extremely sensitive to the accuracy of discrimination of Event Type and to the consistency of Failure Mode selection both of which are recorded in the CMMS.
Unfortunately, most work order records do not discriminate reliably between Failure and Suspension. Neither do they consistently identify the Failure Mode. Misidentifying the Event Type and inconsistently selecting the Failure Mode on the work order causes EXAKT to yield models with shape parameter in excess of 5 and as high as 14.
Such high shape factors mean that decisions made using the EXAKT model will, essentially, be age based, thus defeating the purpose of CBM. At the same time standard deviations will be of the order of >100% of the conditional MTTF (or RULE) rendering the estimate of remaining useful life of doubtful utility.
You may ask why EXAKT in particular, rather than Reliability Analysis (RA) in general (e.g. Weibull analysis), is adversely affected by poor Age data. The answer is that RA was never meant to support day to day decision making since Age alone is too general a factor on which to base daily maintenance decisions. Data inaccuracies will never be noticed in a Weibull analysis. Not so with EXAKT that forces scrutiny of high shape parameter and standard deviation in order to determine the performance of a given predictive decision model.
Age is actually a melange of all relevant yet unmonitored risk factors. EXAKT reveals those influential risk factors and weights them into an optimized decision model. Since EXAKT requires good data and good data can be achieved only with LRCM, EXAKT, therefore, requires LRCM. QED[1].
© 2014, Murray Wiseman. All rights reserved.
- [1]quod erat demonstrandum↩