Functional safety standards provide definitions of two different categories of failures: random failures and systematic failures. These were created during the standards committee discussions of failure types to be modeled in the probabilistic failure analysis. The committee thinking was that systematic failures could be permanently “fixed” by a change in a design or a procedure.
Many companies establish programs to record and analyze failures. A failure rate analysis is performed to determine device failure rates. One problem observed while reviewing these studies is that many people have completely different interpretations of the definitions of random versus systematic failures.
At some sites, those performing the analysis have realized that failures classified as systematic do prevent safety devices from performing their safety function and are therefore dangerous.
This webinar will go over a recent survey performed and also discuss different viewpoints on how to classify failures.
Loren Stewart graduated from Virginia Tech with a BSME. She has over 10 years of professional experience. She currently works for exida consulting as a safety engineer, focusing on the mechanical aspects of their customers. Along with assessing the safety of products and creating FMEDAs and reports, she researches stiction and is creating a database for the 2H initiative according to IEC 61508.