NE154 “Functional Safety in Batch Processes”

from 2023-11-10

from the WG 4.5 Functional Safety was revised in collaboration with the WIB and published today.

The NAMUR Recommendation NE 154 has been revised and may now be obtained from the NAMUR Office.

Abstract NE 154 ‘Functional Safety in Batch Processes’
(Edition: 2023-11-10)

Batch processes pose a challenge for implementing Safety Instrumented Systems (SIS), since batch-produced products often require the selection of different trip points and/or Safety Instrumented Functions (SIF) depending on the recipe used or the current process phase.

However, the relevant safety standards (e.g. IEC 61511-1) do not make a clear distinction between functional safety in batch processes and functional safety in continuous processes. The following topics are relevant for implementing SIFs in batch processes:

  • Recipe handling
  • Operator intervention
  • Synchronisation of process recipes/phases in Basic Process Control System (BPCS) and SIS
  • Variable (recipe-dependent) trip points
  • Disabling/Enabling
  • PFD calculation.

The intention of this document is to identify implementation practices and providing guidelines for functional safety in batch processes needing phase- and/or recipe-dependent trip points and/or SIFs so that a consistent approach can be taken without compromising the effectiveness of the SIS while still meeting the requirements of IEC 61511-1.

Compared with the previous version, the following topics have been updated:

  • Chapter 5: Definitions for “monitoring SIF”, “permissive SIF”, and “safe state” were added.
  • Chapter 6: Information regarding “proof testing” was added.
  • Chapter 10: “monitoring SIF” and “permissive SIF” were added.
  • Chapter 12: Differences between “process triggered”, “hardware triggered”, and “BPCS triggered” synchronization concepts are described.
  • Chapter 13: Examples were added.

This update has the purpose to describe in more detail how the standard can best be applied.

Previous issue: NE154 dated 2016-02-01

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