If you are looking for concise yet accurate answers to the key questions about functional safety standards applicable to components, systems, and industrial plants, you are in the right place. Explore content useful for daily operations, verified by our assessors, certified FS Engineers (TÜV Rheinland).
1. What are the main functional safety standards?
The core standard for functional safety is IEC 61508, which sets out the fundamental requirements that must then be adapted according to the specific application sector.
In summary, the most relevant functional safety standards are:
- IEC 61508, the basic reference for the functional safety of electrical, electronic, and programmable electronic systems
- IEC 61511, specific to plants in the process industry (Oil & Gas, chemicals, energy)
- ISO 13849, for machinery safety and Performance Level calculation; an alternative to IEC 62061
- IEC 62061, for functional safety in the industrial machinery sector; an alternative to ISO 13849
- ISO 26262, a standard specific to the automotive sector, which extends the concept of functional safety to road vehicles
2. Which standards apply to chemical and Oil & Gas plants?
Among the standards applicable to chemical or Oil & Gas plants, when discussing functional safety, IEC 61511 is the technical standard that defines and identifies measures and techniques applicable to a safety system used in the process industry.
Other standards and regulations to be aware of in the chemical or Oil & Gas sector include:
- IEC 61508, from which IEC 61511 is derived, used as a reference for the compliance of the components included in the safety system
- IEC 62443, for OT cybersecurity in industrial automation systems, now also necessary for functional safety purposes
- ATEX, for safety in explosive atmospheres, i.e. in the presence of flammable gases, vapours, or dust
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6 Reasons why IEC standard 61511 is critical3. What is the difference between IEC 61508 and IEC 61511?
IEC 61508 is the basic functional safety reference that defines the minimum requirements for equipment and systems across all industrial sectors. For the proper implementation of these minimum requirements in the process industry, for example, in chemical or Oil & Gas plants—the technical and regulatory reference is therefore IEC 61511. In short, IEC 61508 is aimed at device manufacturers, whereas IEC 61511 is intended for those who design or use systems in process plants. Read the in-depth article.
4. When does IEC 62061 apply instead of IEC 61508?
The IEC 62061 standard applies to the industrial machinery sector, i.e. to the design and safe use of presses, robots, conveyors, or automated lines. Therefore, while IEC 61508 is the basic functional safety reference that defines the minimum requirements for equipment and systems for each specific industrial sector, IEC 62061 comes into play as a result of automation—namely where safety-related control systems (called SCS) play an increasing role in achieving the overall safety of the machine.
IEC 62061 is sometimes applied as an alternative to ISO 13849. Read the in-depth article on ISO 13849.
5. Why is IEC 62443 compatible with IEC 61511?
The two standards are highly compatible: together they make it possible to ensure the safety of industrial plants from both a functional and a cybersecurity perspective. In fact, both standards recommend an approach based on risk assessment and on implementing the safety lifecycle.
For this reason, with few exceptions, the safety path and the security path coincide in terms of configuration management, field feedback, change management, and the assignment of roles and responsibilities.
The recommendation is to manage the phases and sub-phases of the safety lifecycle (safety and security) in parallel within company processes, so as to avoid redundant procedures and corporate policies that are difficult to manage and complicated to apply.
