Simply stated, the 2nd edition of IEC 61508 is the relevant standard for newly developed products and new certifications.  This represents the current best practices on functional safety techniques and measures, and is what the marketplace expects for today’s products. 

Renewed certifications can use the 1st edition of IEC 61508 if that was the edition used when originally certified.  Certifications can be renewed using the 1st edition for up to nine years post- release of the 2nd edition.  Since the 2nd edition was released in 2010, exida will allow certification renewal under the 1st edition until 2019.  This takes into account the long lifespan of many certified products being used in the field.  Certificate owners may choose to renew certifications using the 2nd edition, but in this case, the requirements of the 2nd edition must be met.

The IEC website provides a list of differences between the two editions.  Some significant areas of change include:

• Competence - anyone involved in any phase of the safety lifecycle needs the appropriate competence (i.e. training, technical knowledge, experience, and qualifications) relevant to the specific duties that they have to perform, including requirements for the refreshing, updating, and continued assessment of competence.
• Traceability – there are new requirements for traceability among design specification, safety requirements, and safety validation.
• Tool Suitability – offline software tools used in software development have additional requirements for classification, functional-level failure analysis, and mitigation.