New edition ISO 13849-1:2023 is thicker and friendlier

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Neufassung ISO 13849-1-2023-ist-dicker-und-freundlicher

New edition ISO 13849-1:2023 is thicker and friendlier than its predecessor

2023-08-03 The new edition ISO 13849-1:2023 is thicker and friendlier than its predecessor standard on the functional safety of machinery. Thicker, because it has added a lush 40 pages to the 115 pages of DIN EN ISO 13849-1:2016-06. More friendly, because the entire document has been structured in a user-friendly manner. The DGUV also attests to the user-friendliness of the standard in the conclusion to its new publication “Fourth edition of DIN EN ISO 13849-1, an overview of the main changes from 2023”. More on this in a moment.

ISO 13849-1:2023 with a new look

The International Organization for Standardization (ISO) has published the new edition of ISO 13849‑1 Safety of machinery – Safety-related parts of control systems – Part 1: General principles for design in April 2023. The fourth edition cancels and replaces its technically revised predecessor, ISO 13849-1:2015. Right off the bat, in the publicly viewable preview to the standard, ISO states, «The whole document was reorganized to better follow the design and development process for control systems». And then lists the major changes – new clauses, updated clauses, new annexes, see the listing at the bottom of this post. As soon as the standard is harmonized with the EU standard EN ISO 13849-1 in the EU, after a transitional period, machine and plant manufacturers in the EU will also benefit from the new ease of use.

Changes clause by clause

In its recently published article “Fourth edition of DIN EN ISO 13849-1, An overview of the main changes from 2023”, the DGUV looked at the changes in the standard. On 14 pages, clause by clause, each change is scrutinized. Pure reading pleasure for fans of the basic safety standard for machine control systems. This work definitely provides interested readers with a good overview; it can be read here.

Zero measures for IT security

The Type B1 standard ISO 13849 is one of the most important standards for functional safety in mechanical engineering. That is probably responsibility enough. The introduction to ISO 13849 explicitly states that the standard contains no specific measures for security aspects. In the examples given, of course, is the exclusion of physical safety. The excluded aspects of IT security and cyber security must also be on users’ own minds, as always. Almost in passing, the standard notes that security aspects can have an impact on security functions, with a friendly reference to ISO/TR 22100-4 and IEC/TR 63074 for more information.

More effort against manipulation

In the outline of the new edition of ISO 13849-1:2023, there is a new subclause under the specifications of the safety requirements for “Minimizing the motivation to circumvent safety functions”. In plain language, according to DGUV (2023), this means that incentives to manipulate in order to circumvent safety functions must be minimized – and the practical feasibility of using the machine must be taken into account right from the start.

Also new in this clause: the subclause on remote access. In short, the DGUV’s instructions (2023) on this subject mean: No remote access to a machine if the unnoticed presence of persons in the danger zone is possible.

New edition ISO 13849-1:2023 disempowers part 2

The introduction of the ISO standard immediately clarifies: Requirements for validation in clause 10 replace the requirements of ISO 13849-2:2012, but without the informative annexes (ISO, 2023).

In the view of DGUV (2023), this therefore makes sense: Part 2 of the standard is less well known. If the validation requirements can be found in Part 1, they are automatically upgraded. As an important measure against errors in specification, development and implementation, the same applies to practical implementation.

Insiders are certainly familiar with the validation clauses in ISO 13849-2. In clause 10 of ISO 13849-1:2023, they can find the requirements in 9 subclauses almost in full: principles of validation, validation of the safety requirements specification (SRS), by analysis, by testing, validation of safety functions, safety integrity of SRP/CS, environmental requirements, validation protocol, validation maintenance requirements.

Changes in the new edition ISO 13849-1:2023

In its preface to the new edition of the standard, ISO lists the following main changes:

  • the whole document was reorganized to better follow the design and development process for control systems
  • new Clause 4 on recommendation for risk assessment
  • specification of the safety functions (updated Clause 5)
  • combination of several subsystems (updated in Clause 6)
  • new Clause 7 on software safety requirements
  • new Clause 9 on ergonomic aspects of design
  • validation (updated Clause 8 and moved to Clause 10)
  • new G.5 on management of the functional safety
  • new Annex L on electromagnetic interference (EMI) immunity
  • new Annex M with additional information for safety requirements specification
  • new Annex N on fault-avoiding measures for the design of safety related software
  • new Annex O with safety-related values of components or parts of the control systems

See ISO, original language en

Better reduce the risk

Already in the introduction of ISO 13849-1:2023-04, it is made clear that risk reduction is performed according to ISO 12100:2010. Figure 1 shows how the standard is integrated into the iterative process of risk reduction as stage 2, risk reduction by technical protective measures. If you would like to know more about this process or other changes in the standard: Feel free to ask our functional safety specialists.

Sources cited for the new edition ISO 13849-1:2023-04

ISO, Preview ISO 13849-1:2023(en), Safety of machinery — Safety-related parts of control systems — Part 1: General principles for design, 2023, on 2023-08-03

DGUV, Vierte Ausgabe der DIN EN ISO 13849-1 Die wesentlichen Neuerungen aus 2023 im Überblick (Fourth edition of DIN EN ISO 13849-1 The main innovations from 2023 at a glance), 2023, on 2023-08-03