MTTFd

The MTTFd (mean time to failure, dangerous) is a statistical variable. In other words, it is a value that is determined or calculated empirically and should be viewed as a reference figure that has nothing to do with a “guaranteed service life,” “failure-free period,” or any other similar characteristic. The value denotes the reliability of the components used and is defined as the “expected value of the average time until a dangerous failure occurs,” stated in years.