20 March, 2017

ISO 13849-1 Analysis — Part 6: CCF — Common Cause Failures

by Doug Nix
in Canada, CE Mark, Control Functions, EU European Union, Functional Safety, Guards and Guarding, Hierarchy of Controls, Inherently Safe Design, ISO 13849

Post updated 2019-07-24. Ed. What is a “Common Cause Failure”? There are two similar-sounding terms that people often get confused: Common Cause Failure (CCF) and Common Mode Failure. While these two types of failures sound similar, they are different. A Common Cause Failure is a failure in a system where two or more portions of the…

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27 February, 2017

ISO 13849-1 Analysis — Part 5: Diagnostic Coverage (DC)

by Doug Nix
in Canada, CE Mark, Control Functions, EU European Union, Functional Safety, Guards and Guarding, Hierarchy of Controls, Inherently Safe Design, International, ISO 13849, Robotics /
4 Comments
A graph showing the theoretical "bathtub curve" for product failure rate over the lifetime of the product.

Post updated 2019-07-24. Ed. What is Diagnostic Coverage? Understanding Diagnostic Coverage (DC) as used in ISO 13849-1 [1] is critical to analyzing the design of any safety function assessed using this standard. If you missed a previous part of the series, read it here. In the last instalment of this series discussing MTTFD, I mentioned…

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