EN 17955:2024
(Main)Industrial valves - Functional safety of safety-related automated valves
Industrial valves - Functional safety of safety-related automated valves
This document defines the requirements for how mechanical compliant items in a final element can be evaluated according to the principles of EN 61508 to integrate them into a safety-related system. It provides a method to determine all relevant factors, associated with the product, and thereby meet the specific needs of users of the product.
The basic prerequisite for the application of this document is that the intended use is known. This document describes a system to minimize systematic faults to achieve the targeted Safety Integrity Level (SIL).
This document is applied to single compliant items (e.g. valve, actuator or mechanical portions of solenoid valves) or to assemblies of several of these compliant items and interconnecting compliant items and components (e.g. gears, adaptors, brackets, etc.). Electrical, electronic or programmable electronic components are assessed according to EN 61508.
This document does not apply to:
- manually operated valves;
- items in safety systems or risk-reducing devices that are not assessed and operated according to the principles of functional safety (e.g. automatic safety valves like pressure relief valves).
The methods described can also be used for other mechanical compliant items in a final element of the safety-related system if the applicability is confirmed by appropriate expert knowledge (e.g. dampers, brakes, clutches).
Industriearmaturen - Funktionale Sicherheit sicherheitsbezogener automatisierter Industriearmaturen
Dieses Dokument legt die Anforderungen für die Bewertung konformer mechanischer Objekte in einem Stellglied nach den Grundsätzen von EN 61508 für ihre Integration in ein sicherheitsbezogenes System fest. Es bietet ein Verfahren zur Bestimmung aller relevanten Faktoren, die mit dem Produkt in Verbindung stehen, um so den spezifischen Bedürfnissen der Anwender des Produkts gerecht zu werden.
Die grundlegende Voraussetzung für die Anwendung dieses Dokuments ist die Kenntnis der bestimmungsgemäßen Verwendung. Dieses Dokument beschreibt ein System zur Minimierung von systematischen Fehlern, um den angestrebten Sicherheits-Integritätslevel (SIL) zu erreichen.
Dieses Dokument wird auf einzelne konforme Objekte (z. B. Armatur, Aktor oder mechanische Teile von Magnetschaltern) oder auf Baugruppen aus mehreren dieser konformen Objekte und konformen Verbindungsobjekten (z. B. Getriebe, Adapter, Halterungen) angewendet. Elektrische, elektronische oder programmierbare elektronische Bauteile werden nach EN 61508 bewertet.
Dieses Dokument gilt nicht für:
- handbetätigte Armaturen;
- Objekte in Sicherheitssystemen oder risikomindernde Einrichtungen, die nicht nach den Grundsätzen der funktionalen Sicherheit bewertet und betrieben werden (z. B. automatische Sicherheitsventile wie Druckbegrenzungsventile).
Die beschriebenen Verfahren können auch für andere konforme mechanische Objekte in einem Stellglied des sicherheitsbezogenen Systems verwendet werden, wenn die Anwendbarkeit durch entsprechendes Fachwissen bestätigt wird (z. B. Dämpfer, Bremsen, Kupplungen).
Robinetterie industrielle - Sécurité fonctionnelle des appareils de robinetterie automatisés assurant une fonction de sécurité
Le présent document définit les exigences relatives à la manière dont les articles conformes mécaniques d’un élément final peuvent être évalués conformément aux principes de l’EN 61508 afin de les intégrer dans un système relatif à la sécurité. Il fournit une méthode pour déterminer tous les facteurs pertinents, associés au produit, et répond ainsi aux besoins spécifiques des utilisateurs du produit.
La condition préalable basique pour l’application du présent document est que l’utilisation prévue soit connue. Le présent document décrit un système permettant de minimiser les anomalies systématiques afin d’atteindre le niveau d’intégrité de sécurité ciblé (SIL).
Le présent document s’applique à des articles individuels conformes (par exemple, appareil de robinetterie, actionneur ou parties mécaniques des électrovannes) ou à des assemblages de plusieurs de ces articles conformes d’interconnexion et des composants (par exemple, engrenages, adaptateurs, supports, etc.). Les composants électriques, électroniques ou électroniques programmables sont évalués conformément à l’EN 61508.
Le présent document ne s’applique pas aux :
- appareils de robinetterie à commande manuelle ;
- articles des systèmes de sécurité ou des dispositifs de réduction des risques qui ne sont pas évalués et exploités conformément aux principes de la sécurité fonctionnelle (par exemple, soupapes de sécurité automatiques telles que les soupapes de décharge).
Les méthodes décrites peuvent également être appliquées à d’autres articles conformes mécaniques appartenant à un élément final du système relatif à la sécurité, si l’applicabilité est confirmée par une expertise adéquate (par exemple, amortissements, freins, embrayages).
Industrijski ventili - Funkcionalna varnost varnostnih ventilov in pogonov
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 17955:2023
01-april-2023
Industrijski ventili - Funkcionalna varnost varnostnih ventilov in pogonov
Industrial valves - Functional safety of safety-related valves and actuators
Industrieamaturen - Funktionale Sicherheit sicherheitsbezogener Industriearmaturen und
Antriebe
Robinetterie industrielle - Sécurité fonctionnelle des appareils de robinetterie et
actionneurs liés à la sécurité
Ta slovenski standard je istoveten z: prEN 17955
ICS:
23.060.01 Ventili na splošno Valves in general
oSIST prEN 17955:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 17955:2023
oSIST prEN 17955:2023
DRAFT
EUROPEAN STANDARD
prEN 17955
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2023
ICS 23.060.01
English Version
Industrial valves - Functional safety of safety-related
valves and actuators
Robinetterie industrielle - Sécurité fonctionnelle des Industrieamaturen - Funktionale Sicherheit
appareils de robinetterie et actionneurs liés à la sicherheitsbezogener Industriearmaturen und
sécurité Antriebe
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 69.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17955:2023 E
worldwide for CEN national Members.
oSIST prEN 17955:2023
prEN 17955:2023 (E)
Contents Page
European foreword . 4
Introduction . 5
2 Scope . 6
3 Normative references . 6
4 Terms and definitions . 7
5 Relationship and conformity with EN 61508-1, −2, −4, −6 and −7. 11
6 Basic requirements for development and production . 12
6.1 Evaluation of systematic capability . 12
6.2 Documentation management . 13
6.3 Functional safety management . 13
6.4 Safety lifecycle requirements for development and production of safety-related
automated industrial valves . 13
6.4.1 Objectives and requirements . 13
6.4.2 Mechanical requirements specification . 17
6.4.3 Mechanical validation planning . 18
6.4.4 Mechanical design . 19
6.4.5 Mechanical system integration . 21
6.4.6 Mechanical system installation, commissioning, operation and maintenance
procedures . 22
6.4.7 Mechanical system safety validation . 24
6.4.8 Production . 24
6.4.9 Modification of component . 25
6.5 Verification . 26
6.5.1 Objective . 26
6.5.2 Requirements . 26
6.6 Functional safety assessment . 28
6.6.1 Objective . 28
6.6.2 Requirements . 28
7 Classification of the component . 28
7.1 Demand mode and utilization rate . 28
7.2 Type of final element/component . 31
8 Field failure data . 31
8.1 Field failure data analysis procedure . 31
8.2 Use of field failure data for pre-existing components . 32
9 Qualification testing (during development) . 33
9.1 General. 33
9.2 Test planning/test conditions . 33
9.3 Pre-conditioning of test samples . 33
9.4 Number of required test samples . 33
9.5 Cycle testing and B values according to EN ISO 13849-1:2015, C.4.2 . 33
10D
9.6 Environmental testing . 34
oSIST prEN 17955:2023
prEN 17955:2023 (E)
10 Determination of failure rates . 34
11 Operational testing, maintenance and time restrictions . 34
11.1 Online diagnostic tests . 34
11.2 Proof test. 35
11.3 Proof test coverage (PTC) . 35
11.4 Maintenance . 35
11.5 Useful lifetime . 35
11.6 Storage time . 36
12 Safety manual in addition to an IOM (installation, operation, and maintenance
manual) . 36
Annex A (normative) Checklist for determination of systematic capability . 38
Annex B (normative) Techniques and measures to avoid and control systematic failures . 39
Annex C (normative) List of failure rates for common components . 46
Annex D (normative) L FME(D)A to identify and evaluate the effects of different failure
modes . 49
D.1 FME(D)A . 49
D.2 Input information to carry out an FME(D)A. 49
D.3 FME(D)A procedure . 49
D.4 FMEDA example . 52
D.5 List of functional units and their failure rates with a low utilization rate (LUR) . 56
D.6 List of functional units and their failure rates with a high utilization rate (HUR) . 57
Annex E (informative) Safety manual . 60
Annex F (informative) Examples for the evaluation of the mechanical design . 63
F.1 General . 63
F.2 Examples . 63
F.2.1 Screw connections . 63
F.2.2 Force-locked connections . 64
F.2.3 Form-locked connections (structural part strength) . 65
F.2.4 Springs . 65
F.2.5 Bearings . 66
F.2.6 Gears and force transmission linkages . 66
Annex G (informative) Estimation of random failure rates with Bayesian integration
between “basic” failure rates and field feedback . 67
G.1 General . 67
G.2 Procedure . 67
G.3 Formula . 68
Bibliography . 70
oSIST prEN 17955:2023
prEN 17955:2023 (E)
European foreword
This document (prEN 17955:2023) has been prepared by Technical Committee CEN/TC 69 “Industrial
valves”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
oSIST prEN 17955:2023
prEN 17955:2023 (E)
Introduction
Mechanical components such as valves or actuators are integral parts of many automated safety
instrumented systems. It is therefore necessary to assess the suitability of mechanical components within
the safety functions as well as those of electrical components. This document defines aspects for
implementing safety functions wi
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