prEN xxxxx Industrial valves - Functional safety of safety-related valves and actuators - Preliminary Work Item Proposal has been approved by TC69 for development of a new standard

What is it?:

This standard will define procedures and methods with which all relevant components of automated industrial valve packages can be evaluated according to the rules of IEC 61508-1, -2 and -4 to -7 in order to integrate them into a safety instrumented system (SIS). It will provide a method to determine all relevant factors, associated with the product, to be fully taken into account and thereby meet the specific needs of users of the product. The standard applies to automated industrial valve packages that are used as final elements in a safety instrumented system. It can be applied to single components (e.g. valve, actuator or solenoid valves) or to assemblies of several of these components and interconnecting parts (e.g. gears, adaptors, brackets, etc.).

This standard will not apply to:

- Industrial valves that cannot be integrated in safety instrumented systems according to IEC 61508,
- Automatic safety valves (e.g. pressure relief valves),
- Manually operated valves.
- Components in safety systems or risk-reducing devices that are not designed, assessed and operated according to the principles of functional safety.

Why is it important?:
This initiative is very much needed because IEC 61508 is mainly aimed at addressing how electronics/software technologies can fail, not mechanical components. The new standards basic premise is that it is not always possible to parameterise mechanical components with random probabilistic failure rates in the same way as it can with mass produced electrical/electronic parts. The draft standard provides an approach that is targeted, clear to understand and more practical to follow, whilst aiming to derive the parameters needed to allow system integration according to IEC 61508 / 61511.

Supersedes: Will create an IMPORTANT new standard.

Published in Valve User Magazine Issue 47


Winter 2018 // Issue 47
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