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Reply to "Difference between FMEA and FMECA"

Steve,
You say,
quote:
Asset criticality is a second order consideration for evident failure modes

Risk is what we want to manage. Most Regulators would require us to demonstrate that our Maintenance Program reduces Risk to ALARP levels. I do not think they will be too impressed if our Program focuses on Cost alone, however marketable that concept is to many companies who do realize that it is a slippery road to take.
Risk evaluation requires us to look at both Consequence and Probability of failures. Risk equates to Criticality, so unless you think risk is unimportant, I find your above comment strange and misleading. The fact that some PMO systems do not consider probability in a systematic way, to save time and money is a lacuna, not a strength. You have argued in other threads that good quality data is hard to find in CMMS, which is a fair observation. But it is certainly possible to find reasonable failure frequency data, given a mindset that does not dispense with probability as too difficult or costly to handle.
Your argument about P-F curves is spot on. We need good data about P-F intervals too, but I do not know of many companies that plot P-F curves either. The concept is however important and we can get that information from operators and maintainers close to the scene of action.
The important point about failure rate data is that the outcomes are not as sensitive to their accuracy as some people think. The the relationship is logarithmic; errors of 50% or more can be tolerated, i.e., the maintenance interval will not change a great deal due to such errors. In most cases ball-park estimates are good enough. If you can find the data for
quote:
.. hard time replacement is determined by safe life
you can find other (failure) data just as easily.
Don't dismiss FMECA, it has its uses, just as RCA, IPF or RCM do; every toolbox has a variety of tools to suit each situation. We need more than a hammer, unless every object we see is a nail.
RM
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