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EN ISO 13849-1:2023 | Most important new features

EN ISO 13849 1 2023 New features

EN ISO 13849-1:2023 | Most important new features DGUV

ID 21658 | 09.04.2024 / Documento completo in allegato

The International Organisation for Standardisation (ISO) has published a new version of the basic safety standard for machine controls, ISO 13849-1 “Safety of machinery – Safety-related parts of control systems – Part 1: General principles for design”. A quarter of a century after the first publication of this standard, this is now a completely revised and modernised version. There is still quite some time before the EU Standard EN 13849-1 is harmonised, before the transitional three-year period has been completed and before the new version becomes binding. Yet it is nevertheless worth taking an early glimpse at its new features.

Whereas the changes in the third edition of 2015 were merely editorial, to improve readability and usability, the latest update contains a range of more substantial adjustments and additions.

Illustration Major changes

Illustration: Major changes to the design process for SRP/CS in the fourth edition of the standard

[...]

2 Section 1: Scope

As in the previous edition, the authors point out that the standard only applies to SRP/CS for a high demand or continuous mode of operation. According to definition 3.1.44, the demand for this mode is more frequent than once a year. For SRP/CS in low demand mode, i.e. where the frequency is less than once a year – for instance in the processing industry – the authors now refer expressly to the IEC 61508 series of standards.

IT security aspects are not covered by the standard, but the authors point out that the such aspects can also impact safety functions. For further details, reference is given to ISO/TR 22100-2 and IEC/TR 63074.

[...]

5 Section 5: Specification of safety functions and Annex M

Safety functions now need to be defined in detail as part of a safety requirements specification (SRS) The definition of each safety function continues to be based on the risk assessment and reduction process as per EN ISO 12100. The required details for a precise and complete definition of each safety function include the following items:

The required details for a precise and complete definition of each safety function include the following items:

- brief description or title (as a unique reference),
- triggering event that demands the safety function,
- required reaction that must be initiated by the safety function in order to achieve the intended safe state,
- required performance level PLr,
- permitted response time, i.e. the time between demanding the safety function and achieving the safe state,
- operating modes in which the safety function must be active,
- interfaces of the safety function with the machine control system and with other safety functions,
- if necessary, a description of the failure response, i.e. how the machine can be returned to a safe state after a fault has been detected in a functional channel,
- behaviour of the machine in the event of energy loss, e.g. a requirement for non-return valves directly on a cylinder or additional mechanical brakes (separation into two safety functions is also possible – one with available energy or a second one without available energy),
- demand rate for the safety function,
- prioritisation of different safety functions that can be enabled at the same time and can trigger conflicting responses,
- additional safety requirements from product standards (type-C standards),
- conditions permitting a restart after the safety function has been requested.

[...]

16 Annex L: Electromagnetic interference immunity

Since the third edition of the standard, there has been the introduction of a new generic standard – IEC 61000-6-7 – on immunity requirements for safety-related functional safety systems. To facilitate their implementation, a new informative Annex L now provides guidance on the implementation of the required measures for electromagnetic interference immunity. Depending on the application, four alternative options are provided:

A. Electromagnetic immunity requirements from an applicable product standard have the highest priority (independent of the PL that is to be achieved) and override the general requirements of the generic standard.
B. For PL a and PL b, compliance with the lower immunity requirements of IEC 61000-6-2 for industrial settings that are not designed for functional safety is considered sufficient.
C. Up to PL d (and even up to PL e if the requirements for category 4 are met), the necessary immunity can also be achieved through protective measures at the system level, such as shielding, filters, interference-resistant cables, separation, fault detection or risk analysis, instead of through interference immunity tests. This alternative verification strategy is also expressly mentioned in IEC 61000-6-7, 4.1, Note 1. Table L.1 of the standard lists 23 different measures for this purpose, with compliance resulting in 10 to 30 points. The immunity requirements are considered to be met if the total score for two-channel systems (Categories 2, 3 and 4) is at least 280, or if the total score for single-channel systems (Categories B and 1) is at least 230. Five measures are not applicable to single-channel subsystems. Eight of the listed measures are marked as strongly recommended: If they are applicable but have not been implemented, detailed justification must be provided as to how immunity is to be achieved in an equivalent manner.
D. Up to PL e, compliance with the increased immunity levels can be demonstrated by applying IEC 61000-6-7 or other general EMC standards on functional safety, such as IEC 61326-3-1.

[...] segue in allegato

Fonte: DGUV

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Testata editoriale iscritta al n. 22/2024 del registro periodici della cancelleria del Tribunale di Perugia in data 19.11.2024