Is There a No MTBF Standard?

Sure, don't use MTBF.

You can use that as a standard or directive or policy or however you want.

The IEC set of durability standards have been slowing shedding reference and use of MTBF. That is a good thing and I thank them for their leadership.

Is it a standard's body role to let you know what is not useful? To detail what not to do or use? I don't think so. Standards provide a common language and set of methods so we all can work well together.

The idea of standards is to minimize confusion and misunderstandings.

If you simply avoid using MTBF you too will minimize confusion and misunderstandings.

Establish a personal standard

You can help move your organization and industry toward useful measures of reliability by

• Asking others for their definition of MTBF
• Asking for the duration over which the MTBF value is valid
• Asking those requesting MTBF to explain what they really want
• And, to never assume those around you understand MTBF

Be vocal, ask questions, challenge assumptions, and plot the data. You can help by avoiding the possibility of mis-use of MTBF.

Establish a company policy

Another way to help those around you is to use reliability directly. Instead of using the inverse of a constant failure rate, state the probability of success over a specific duration. Include function and environment as appropriate.

• When you review or create reliability specifications, do not use MTBF.
• Work with suppliers by providing complete reliability specifications and not accepting MTBF from them.
• Create data sheets and customer information using reliability.

Again, by not using MTBF you are avoiding the perils that accompany that metric. You may enjoy the questions and conversations as there will much less confusion.

If it would be useful, draft a simple company policy statement outlining how to specify and measure reliability. Make it official.

We don't need an industry standard to change the standard way our industries talk about reliability. Just start by using reliability and enjoy the clarity.

If there is a standard out there that requires the avoidance of MTBF - I sure would like to know about it. In the meantime, use something that is useful instead.

Fred Schenkelberg is an experienced reliability engineering and management consultant with his firm FMS Reliability. His passion is working with teams to create cost-effective reliability programs that solve problems, create durable and reliable products, increase customer satisfaction, and reduce warranty costs. If you enjoyed this article consider subscribing to the ongoing series at Accendo Reliability.