Note: This article is adapted from the original German text, with changed cross-references to the international standards. For a more detailed summary of the legal framework in Germany, please refer to the German version of this blog.

IEC 61508 and IEC 61511 are the recognized international standards for the implementation of best practice and ALARP principles for functional safety management. In German-speaking countries, they are supplemented by the derivative VDI / VDE 2180 series of standards. Compliance with these standards is not required by law, however, can be considered as a ‘prerequisite’ that allows the recognized state of the art and the associated safety objectives to be met. In this case, in the event of an incident, the burden of proof generally lies with the authorities, courts and prosecutors and not with the operator.

For industrial process plant, a typical ‘Code Hierarchy’ is as follows (basis – regulatory framework in Germany)

The standards relevant to Functional Safety comprising ‘state of the art’ are in various stages of update. Although the international basis code IEC 61511 2nd edition was updated in 2016, the corresponding German version DIN EN 61511 was only reissued in January 2019. In the meantime the new version of IEC 61511 is being used internationally, including it‘s new requirements in regard to functional safety.

The table below gives the current status of relevant international standards with status December 2021.

International Standards, defining ‚state of the art‘
in relation to Functional Safety
Version / Status
IEC 61508-1 Ed. 2 2010-04
IEC 61508-2 Ed. 2 2010-04
IEC 61508-3 Ed. 2 2010-04
IEC 61508-4 Ed. 2 2010-04
IEC 61508-5 Ed. 2 2010-04
IEC 61508-6 Ed. 2 2010-04
IEC 61508-7 Ed. 2 2010-04
IEC 61511-1 Ed. 2 2016-02
Ed. 2.1 issued 2017-08
IEC 61511-2 Ed. 2 2016-02
IEC 61511-3 Ed. 2 2016-07
IEC/TR 61511-4 2020-03
IEC 62061 Ed. 1.2 2015-06
DIN EN ISO 12100 2011-03
DIN EN ISO 13849-1 2020-08 Draft
DIN EN ISO 13849-2 2013-02