A few months ago at a IEC Dependability standards meeting, I met Thomas Young Olesen of Grundfos and we talked a little about NoMTBF. He said their company has a polity to not use MTBF. YES! So I asked for permission to post some information about the policy.
One interesting part of their internal site was a MTBF Calculator.
This is just a screen shot, yet by clicking the “I’m feeling lucky” link to get a new number. There is a short animation of rolling numbers (ala slot machine) and a new number appears. I’m told is a random number generator behind the scenes and suitable substitute for MTBF – given they are rather meaningless to begin with.
I like this company and this policy.
Thomas also sent me a short slide set that explains the policy a little more conventionally.
Does your company have such a policy? If so, please ask for permission to share here and lauded as one of the enlighten companies of the NoMTBF era. If not, why not?
Johannes Dissing says
I wrote the article on Grundfos’ Intranet after someone used 3000 Euro of the company money buying a MTBF. They might as well have burned them 🙂
Then we added the slides in order to give a serious touch to what was actually started as a joke for April 1st. That made it possible for the document to survive, and we now have a clear statemet about MTBF policy – No MTBF policy, it is.
The 3000 Euro (4050 dollars) expensive MTBF report stated a 10% cummulated failure rate after 14 years. But then, in the chapter Notes, it was written:
“Electrolytic capacitors (….) and fan show, in addition to the random failures, a wear-out failure mode, which has effect significantly earlier than for the other components.
According to well-known manufacturers the wear-out of electrolytic capacitors has effect after about 10 to 15 years depending on operating conditions (….)
The fan used has according to data sheet a 10% failure-life of 2.3 years at
My conclusion is that the MTBF is meaningless. The fan is needed, and if it fails after two or three years then the whole machine fails.