Hot Spot prEN 17955

Functional safety of safety-related valves and actuators ballot

What is it?

CEN TC 69 has been working on the development of a new EN standard covering functional safety of safety-related valves and actuators for a number of years as a preliminary work item. The attached draft standard prEN 17955 has now been published for ballot.

This draft document defines the procedures and methods with which all relevant mechanical components of automated industrial valve packages that are used as final elements in a safety instrumented system can be evaluated according to the principles of EN 61508-1, −2, −4, −6 and −7 in order to integrate them into a safety instrumented system (SIS). It is applied to single components (e.g. valve, actuator or mechanical parts of solenoid valves) or to assemblies of several of these components and interconnecting parts (e.g. gears, adaptors, brackets, etc.).

The standard does not apply to manually operated valves or automatic valves such as safety valves that are not assessed and operated according to functional safety principles.

If BVAA members have any comments on the attached draft standard then please submit them to the secretariat by 31-03-23. Comments received will be considered by the BVAA SILS TEG when submitting the BVAA response to BSI prior to the close of the CEN ballot.

Why is it Important?

This standard is important because it provides methods to assess the performance of mechanical components, like valves and actuators used in safety instrumented systems, in order to provide a SILS rating for the safety system. This standard is the first document to address in detail the methods to be used for assessing and calculating the functional safety performance of these mechanical devices, particularly with respect to their reliability and failure rates.

Adoption of the final standard by end users and system integrators will require valve and actuator manufacturers to follow the prescribed reliability testing and failure analysis methodology when assigning functional safety related performance ratings to their products. It is important that the proposed requirements are reviewed by manufacturers to ensure that they are both practical and effective to apply to their products.

Did we miss anything?

Hot Spots are intended to alert members and provide a brief overview of new standards, activities or procedures that are being introduced in the industry. If there is key information missing that would be helpful, please let us know so that we can improve our future service.

Please Note: This Hotspot is for information purposes, and we invite comments from BVAA members only. Please also note that at time of publication ballots may be closed. For more information, please contact the Secretariat.

BVAA Members: Did you know we have a hotspot tab on the BVAA website? Head over to www.bvaa.org.uk/login-here.asp and log into the member only area. You then need to select ‘Hotspots’ for the latest. For information on how to access the member only area of the website please contact jane@bvaa.org.uk. 

Published: 23rd February 2023