EN 15233:2007

Methodology for functional safety assessment of protective systems for potentially explosive atmospheres

This European Standard provides guidance on the procedure and information required to allow functional safety assessment to be carried out for the design of protective systems.
The purpose of this European Standard is to assist technical standardization committees responsible for specific families of protective systems in preparing safety standards. Such standards shall be as homogenous as possible and shall have the basic structure of functional safety assessment as it is stated in this standard.
If there are no specific standards for a particular protective system, the manufacturer shall use this standard for functional safety assessment of this protective system.
In this procedure the following information is to be taken into account to ensure a sufficient level of functional safety:
a)   intended use,
b)   possible operating faults,
c)   reliability of protective systems,
d)   misuse which can reasonably be anticipated.
A sufficient level of functional safety is characterized by the following objectives:
1)   System can stop an explosion at a very early stage or reduce the impact of an explosion to an acceptable level.
2)   In the event of faults, failures and/or interference ) the capacity to function remains effective by use e.g. of fail safe techniques or redundancy.
This European Standard does not cover identification of possible ignition sources.
NOTE 1   The identification of possible ignition sources is covered by EN 15198.
This European Standard only deals with the functional behaviour of the protective system i.e. hazards caused by malfunctions, e.g. false activations are excluded.
This European Standard specifies neither specific methods to analyse fault conditions, nor specific requirements for a given type of protective system (see EN 1127 1). It specifies the methodology of functional safety assessment.
(continued)

Methodik zur Bewertung der funktionalen Sicherheit von Schutzsystemen für explosionsgefährdete Bereiche

Méthodologie relative à l'évaluation de la sécurité fonctionnelle des systèmes de protection pour atmosphères explosibles

La présente norme européenne donne des lignes directrices relatives au mode opératoire et aux informations requises pour permettre la mise en oeuvre de l'évaluation de la sécurité fonctionnelle pour la conception des systèmes de protection.
La présente Norme européenne a pour objet d'aider les comités techniques de normalisation, responsables de familles spécifiques de systèmes de protection, à préparer les normes de sécurité. Il est recommandé que ces normes soient aussi homogènes que possible et qu’elles aient la structure de base indiquée dans la présente norme pour l’évaluation de la sécurité fonctionnelle.
En l’absence de normes spécifiques pour un système de protection donné, il est recommandé que le fabricant utilise cette norme pour l’évaluation de la sécurité fonctionnelle de ce système de protection.
Dans ce mode opératoire, les informations suivantes doivent être prises en compte pour assurer un niveau de sécurité fonctionnelle suffisant :
a)   l'utilisation prévue ;
b)   les défauts de fonctionnement possibles ;
c)   la fiabilité des systèmes de protection ;
d)   le mauvais usage pouvant être raisonnablement attendu.
Un niveau de sécurité fonctionnelle suffisant est caractérisé par les objectifs suivants :
1)   le système peut arrêter l'explosion dès son tout début ou réduire l'impact d'une explosion à un niveau acceptable ;
2)   en cas de défauts, de défaillances et/ou d'interférences  ) la capacité de fonctionner reste effective par l'utilisation, par exemple, de techniques de sécurité ou de redondance.
La présente Norme européenne ne traite pas de l'identification des sources d'inflammation possibles.

Metodologija za varnostno oceno delovanja zaščitnih sistemov za potencialno eksplozivne atmosfere

General Information

• Status: Published
• Publication Date: 21-Aug-2007
• Withdrawal Date: 28-Feb-2008
• ICS: 13.230 - Explosion protection
• Technical Committee: CEN/TC 305 - Potentially explosive atmospheres - Explosion prevention and protection
• Drafting Committee: CEN/TC 305/WG 4 - Terminology and Methodology
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Completion Date: 06-Jul-2023
• Directive: 2014/34/EU - Directive 2014/34/EU Of The European Parliament And Of The Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (recast)
• Directive: 94/9/EC - Directive 94/9/EC of the European Parliament and the Council of 23 March 1994 on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Mandate: M/BC/CEN/92/46 - Standardization mandate assigned to CEN/CENELEC concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Ref Project: SIST EN 15233:2007 - Methodology for functional safety assessment of protective systems for potentially explosive atmospheres

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Methodology for functional safety assessment of protective systems for potentially explosive atmospheresRWHQFLDOQRMéthodologie relative a l'évaluation de la sécurité fonctionnelle des systemes de protection pour atmospheres explosiblesMethodik zur Bewertung der funktionalen Sicherheit von Schutzsystemen für explosionsgefährdete BereicheTa slovenski standard je istoveten z:EN 15233:2007SIST EN 15233:2007en,fr,de13.230Varstvo pred eksplozijoExplosion protectionICS:SLOVENSKI
STANDARDSIST EN 15233:200701-oktober-2007

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15233August 2007ICS 13.230 English VersionMethodology for functional safety assessment of protectivesystems for potentially explosive atmospheresMéthodologie relative à l'évaluation de la sécuritéfonctionnelle des systèmes de protection pour atmosphèresexplosiblesMethodik zur Bewertung der funktionalen Sicherheit vonSchutzsystemen für explosionsgefährdete BereicheThis European Standard was approved by CEN on 13 July 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15233:2007: E

Example of a functional safety assessment.15 Annex B (informative)
Methods for failure identification and functional safety assessment.20 Annex ZA (informative)
Relationship between this European Standard and the Essential Requirements of EU Directive 94/9/EC.23 Bibliography.24

For relationship with EU Directive 94/9/EC, see informative Annex ZA, which is an integral part of this document. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.

1) Interference is everything in normal operation that can disturb the normal operation of the system e.g. electromagnetic waves, heat, flames and pressure waves.

NOTE 1 Functional safety covers all aspects where safety depends on the correct functioning of the protective system and other technology safety-related systems.
NOTE 2 This definition deviates from the definition in EN 61508-4 to reflect differences in explosion safety terminology. 3.3 protective system device other than components of the equipment, which is intended to halt incipient explosions immediately and/or to limit the effective range of an explosion and which is placed separately on the market as autonomous system [EN 13237:2003, A.5] 3.4 functional safety estimation determination of the probability of occurrence of the failures violating the functional safety of the protective system 3.5 functional safety evaluation procedure to determine whether the functional safety of the protective system meets the predefined acceptance criteria 4 General requirements 4.1 Basic concept Functional safety assessment is a series of logical steps (see Figure 1) that enable designers and safety engineers to examine in a systematic way, the function of a protective system or a part of it. The objective shall be to achieve an adequate level of functionality and reliability according to the state of the art and technical and economic requirements at the time of construction.

a) description of the protective system (5.2); b) identification of failures (5.3); c) functional safety estimation (5.4); 1) functionality; 2) reliability; d) functional safety evaluation (5.5). These four steps are the basis for the decision whether the intended level of functional safety necessary for the intended use is achieved. The result of the assessment shall be detailed in the technical documentation (see Clause 6). If the required function and level of reliability is not achieved, it shall be necessary to improve the protective system or to define an appropriate intended use.
NOTE The choice of the suitable measures is not part of the standard. If the assessment is done by the manufacturer the result of the assessment shall be detailed in the technical documentation (see Clause 6). Decisions in functional safety assessment shall be supported by qualitative methods complemented, where appropriate, by quantitative methods. 4.2 Extent of functional safety assessment The protective system shall be assessed on the basis of the information specified in 4.3.
The functional safety assessment shall be limited to the intended use and the misuse, which can reasonably be anticipated for a particular protective system. NOTE Misuse which can reasonably be anticipated means an incorrect use and/or operation of the protective system by the operator due to negligence or misunderstanding. Misuse is not part of the normal operation. Intent is not included in foreseeable misuse. 4.3 Information needed The information needed to perform the functional safety assessment shall include the following where appropriate: a) intended use; b) safety characteristics used for the design of protective systems;
c) requirements for maintenance; d) actual and foreseeable surrounding area conditions; e) relevant design drawings; f) results of design calculations made, examinations carried out; if available:

NOTE The data is used to define foreseeable operation requirements related to reliability, serviceability, durability, disposability, benign failure and failsafe characteri
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