EN 50402:2017
(Main)Electrical apparatus for the detection and measurement of combustible or toxic gases or vapours or of oxygen - Requirements on the functional safety of gas detection systems
Electrical apparatus for the detection and measurement of combustible or toxic gases or vapours or of oxygen - Requirements on the functional safety of gas detection systems
This European Standard is applicable to apparatus and systems for the detection and measurement of flammable or toxic gases or vapours or oxygen. This European Standard is a product standard which is based on EN 61508 (all parts) and for gas detection systems covers both low and high demand mode at SIL capabilities of 1, 2 or 3 only. Gas detection apparatus and gas detection systems are developed as generic products. This standard covers part of the phase 10 “realisation” of the overall safety lifecycle defined in Figure 2 of EN 61508-1:2010. Configuration and integration into specific applications is not covered by this standard. In the event of conflict between the requirements of this standard and those of EN 61508, EN 50402 will take precedence. NOTE 1 Applications requiring a SIL capability of 4 for a gas detection system are not practicable. NOTE 2 This European Standard is dedicated mainly to fixed apparatus. For portable gas detectors claiming a SIL higher than 1, this European Standard may be applied. This European Standard supplements the requirements of the European Standards for electrical apparatus for the detection and measurement of flammable gases, vapours (e.g. EN 60079-29-1 or EN 60079-29-4), toxic gases (e.g. EN 45544) or oxygen (e.g. EN 50104). NOTE 3 These European Standards are called in the text "metrological standards". The examples above show the state of the standardisation for industrial applications at the time of publishing this European Standard. There may be other metrological standards covering other application fields, for which this European Standard is also applicable. EN 50271 specifies minimum requirements for apparatus using software and/or digital components. It also defines additional optional requirements for compliance with SIL 1 in low demand mode operation. EN 50402 includes all requirements of EN 50271. EN 50402 is also dedicated to apparatus and gas detection systems and/or components and should be used instead of EN 50271 in the following cases: - At SIL 1 when the system contains components not covered by EN 50271; - At SIL 2 and SIL 3; - At all SILs when non-digital based apparatus is used. Applying the above-mentioned metrological standards will ensure the measuring performance is adequate in normal operation of a gas detection system. Additionally the requirements of this European Standard address the functional safety of gas detection systems and encompass criteria for reliability, fault tolerance and avoidance of systematic failures. The avoidance and control of systematic failures will be covered by the requirements for the development processes and techniques and diagnostic measures chosen in the design. This European Standard will lead to the characterisation of the gas detection system by a SIL-capability and related hardware failure rate representing a hierarchical order of safety levels. This will allow the user to incorporate the gas detection system into an overall safety system according to the safety integrity levels of EN 61508 (all parts). This European Standard is applicable for gas detection systems, which may consist of the following functional units: - gas-sampling; - sensor; - signal transmission; - input to control unit; - signal processing in control unit; - output from control unit. This European Standard does not specify requirements for the installation and maintenance of gas detection systems. It also does not specify the physical positioning of measuring points / locations. This European Standard does not specify which SIL-capability is sufficient for which application. NOTE 4 The SIL-capability required for an application will be specified by the user (see Clause 9 and Annex A ).
Elektrische Geräte für die Detektion und Messung von brennbaren oder toxischen Gasen und Dämpfen oder Sauerstoff - Anforderungen an die funktionale Sicherheit von Gaswarnsystemen
Diese Europäische Norm gilt für Gaswarngeräte und -Systeme zur Detektion und Messung von brennbaren oder toxischen Gasen oder Dämpfen oder Sauerstoff. Diese Europäische Norm ist eine Produktnorm auf Grundlage der EN 61508 (alle Teile) und umfasst für Gaswarnsysteme sowohl Anwendungen mit niedriger als auch mit hoher Anforderungsrate ausschließlich für die SIL-Fähigkeiten 1, 2 oder 3. Gaswarngeräte und Gaswarnsysteme werden als generische Produkte entwickelt. Diese Norm deckt Teile der Phase 10 "Realisierung" des in Bild 2 der EN 61508-1:2010 definierten Gesamt-Sicherheitslebenszyklus ab. Die Konfiguration und Integration für spezifische Anwen¬dungen werden von dieser Norm nicht behandelt. Im Falle eines Widerspruchs zwischen den Anforderungen dieser Norm und denen de EN 61508 besitzt die prEN 50402 Vorrang. ANMERKUNG 1 Anwendungen, die eine SIL-Fähigkeit 4 für ein Gaswarnsystem erfordern, sind nicht praktikabel. ANMERKUNG 2 Diese Europäische Norm bezieht sich auf ortsfeste Geräte. Für tragbare Gaswarngeräte, die ein SIL hö¬her als 1 beanspruchen, darf diese Europäische Norm angewendet werden. Diese Europäische Norm ergänzt die Anforderungen der Europäischen Normen an elektrische Geräte zur Detektion und Messung von brennbaren Gasen, Dämpfen (z. B. EN 60079-29-1 oder EN 60079-29-4), to-xischen Gasen (z. B. EN 45544) oder Sauerstoff (z. B. EN 50104). ANMERKUNG 3 Diese Europäischen Normen werden im Text als "messtechnische Normen" bezeichnet. Die oben genannten Beispiele stellen den Stand der Normung für industrielle Anwendungen zum Zeitpunkt der Veröffentlichung dieser Europäischen Norm dar. Es können weitere messtechnische Normen für andere Anwendungsfelder bestehen, auf die diese Norm ebenfalls anwendbar ist Die EN 50271 beschreibt die Mindestanforderungen für Geräte, die Software und/oder digitale Komponenten benutzen. Sie legt außerdem zusätzliche optionale Anforderungen zur Konformität mit SIL 1 im Betrieb mit niedriger Anforderungsrate fest. EN 50402 schließt alle Anforderungen der EN 50271 ein. Die EN 50402 ist ebenfalls für Geräte und Gaswarnsysteme und/oder Komponenten bestimmt und sollte in folgenden Fällen anstelle von EN 50271 benutzt werden: - für SIL 1, wenn das System Komponenten enthält, die nicht durch EN 50271 abgedeckt sind; - für SIL 2 und SIL 3 - für alle SIL’s bei nicht auf Digitaltechnik basierenden Geräten. Die Anwendung der obengenannten messtechnischen Normen stellt ein angemessenes messtechnisches Betriebsverhalten im Normalbetrieb des Gaswarnsystems sicher. Zusätzlich beziehen sich die Anforderungen dieser Europäischen Norm auf die funktionale Sicherheit von Gaswarnsystemen und umfassen Kriterien für Zuverlässigkeit, Fehlertoleranz und Vermeidung systematischer Ausfälle. Die Vermeidung und Beherrschung systematischer Fehler wird durch Anforderungen an Entwicklungsprozesse und Verfahren sowie während der Entwicklung gewählte Diagnosemaßnahmen abgedeckt. Diese Europäische Norm führt zu einer Einstufung des Gaswarnsystems in Form einer SIL-Fähigkeit und von damit verbundenen Hardwareausfallraten. Sie spiegelt eine hierarchische Anordnung von Sicherheitsstufen wider. Dadurch wird es dem Anwender ermöglicht, das Gaswarnsystem in ein Gesamtsicherheitssystem nach den Sicherheits-Integritätsleveln der EN 61508 (alle Teile) einzubinden. Diese Europäische Norm ist auf Gaswarnsysteme anwendbar, die aus folgenden funktionalen Einheiten be-stehen können: - Gasprobenentnahme; - Sensor; - Signal-Übertragung; - Eingang der Steuereinheit; - Signalverarbeitung in der Steuereinheit; - Ausgang der Steuereinheit. Diese Europäische Norm legt keine Anforderungen an die Installation und Wartung von Gaswarnsystemen fest. Sie legt auch nicht die Platzierung von Messstellen/Messorten fest.
Matériel électrique pour la détection et la mesure des gaz ou vapeurs combustibles ou toxiques ou de l'oxygène - Exigences relatives à la sécurité fonctionnelle des systèmes de détection de gaz
La présente norme européenne s'applique aux matériels et systèmes utilisés pour la détection et le mesurage de gaz ou de vapeurs inflammables ou toxiques, ou de l'oxygène. La présente Norme européenne est une norme de produit fondée sur l’EN 61508 (toutes les parties) et couvre à la fois le mode à faible sollicitation et le mode à sollicitation élevée pour les systèmes de détection de gaz aux capacités de SIL 1, 2 ou 3 uniquement. Les matériels et systèmes de détection de gaz sont développés en tant que produits génériques. La présente norme traite en partie de la phase 10 “réalisation” du cycle de vie de sécurité globale défini à la Figure 2 de l’EN 61508-1:2010. La configuration et l’intégration en applications spécifiques ne sont pas traitées par la présente norme. En cas de conflit entre les exigences de la présente norme et celles de l’EN 61508, le prEN 50402 prévaut. NOTE 1 Les applications qui exigent une capacité de SIL 4 pour un système de détection de gaz ne sont pas réalisables. NOTE 2 La présente Norme européenne est dédiée principalement aux matériels fixes. Pour les détecteurs de gaz portables qui déclarent un niveau SIL supérieur à 1, la présente Norme européenne peut être appliquée. La présente Norme européenne complète les exigences des normes européennes relatives aux matériels électriques pour la détection et le mesurage de gaz et de vapeurs inflammables (par exemple, EN 60079-29-1 ou EN 60079-29-4), de gaz toxiques (par exemple, EN 45544) ou de l'oxygène (par exemple, EN 50104). NOTE 3 La présente Norme européenne qualifie ces normes européennes de ''normes métrologiques''. Les exemples susmentionnés représentent l'état de la normalisation relative aux applications industrielles au moment de la publication de la présente Norme européenne. Il peut exister d'autres normes métrologiques traitant d'autres domaines d'application, pour lesquels la présente Norme européenne s'applique également. L’EN 50271 spécifie les exigences minimales concernant les matériels qui utilisent des composants logiciels et/ou numériques. Elle définit également des exigences facultatives supplémentaires concernant la conformité à SIL 1 en mode de fonctionnement à faible sollicitation. Le prEN 50402 inclut toutes les exigences de l’EN 50271. Le prEN 50402 est également dédié aux matériels et systèmes et/ou composants de détection de gaz et il convient de l’utiliser en lieu et place de l’EN 50271 dans les cas suivants: – au niveau SIL 1 lorsque le système contient des composants non traités par l’EN 50271; – aux niveaux SIL 2 et SIL 3; – à tous les niveaux SIL en cas d’utilisation de matériels non numériques. L'application des normes métrologiques susmentionnées garantit le caractère adéquat des performances de mesure en exploitation normale du système de détection de gaz. Les exigences de la présente Norme européenne traitent en outre de la sécurité fonctionnelle des systèmes de détection de gaz et englobent les critères de fiabilité, de tolérance aux anomalies et d'évitement des défaillances systématiques. L’évitement et le contrôle des défaillances systématiques sont traités par les exigences concernant les processus et techniques de développement, ainsi que les mesures de diagnostic choisies lors de la conception. La présente Norme européenne conduit à la caractérisation du système de détection de gaz par une capacité de SIL et du taux de défaillance du matériel associé, qui représente un ordre hiérarchique des niveaux de sécurité. Ceci permet à l'utilisateur d'intégrer le système de détection de gaz à un système de sécurité globale selon les niveaux d'intégrité de sécurité définis dans l’EN 61508 (toutes les parties). ......
Električne naprave za zaznavanje in merjenje gorljivih ali strupenih plinov, hlapov ali kisika - Zahteve za funkcionalno varnost sistemov za odkrivanje plina
Ta evropski standard se uporablja za aparate in sisteme za zaznavanje in merjenje vnetljivih ali strupenih plinov, hlapov ali kisika.
Ta evropski standard je standard za izdelek, ki temelji na standardu EN 61508 (vsi deli), in zajema način z nizkimi in visokimi zahtevami sistemov za odkrivanje plina, in sicer samo pri zmogljivostih ravni celovite varnosti (SIL) 1, 2 ali 3. Aparati in sistemi za odkrivanje plina so generični izdelki. Ta standard zajema del »realizacije« 10. faze v celotnem varnostnem življenjskem ciklu, ki je določen na sliki 2 standarda EN 61508-1:2010. Konfiguracija in integracija v posebne načine uporabe nista del tega standarda.
V primeru neskladij med zahtevami tega standarda in zahtevami standarda EN 61508, ima prednost standard EN 50402.
OPOMBA 1: Načini uporabe, ki za sisteme za odkrivanje plina zahtevajo raven celovite varnosti 4, niso uporabni.
OPOMBA 2: Ta evropski standard je namenjen predvsem za nepremične aparate. Ta evropski standard se lahko uporablja za prenosne javljalnike plina, z ravnjo celovite varnosti, višjo od 1.
Ta evropski standard dopolnjuje zahteve evropskega standarda za električne aparate za odkrivanje in merjenje vnetljivih plinov, hlapov (npr. EN 60079-29-1 ali EN 60079-29-4), strupenih plinov (npr. EN 45544) ali kisika (npr. EN 50104).
OPOMBA 3: Ti evropski standardi so v besedilu imenovani »meroslovni standardi«.
Spodnji primeri prikazujejo standardizacijo industrijskih načinov uporabe v času objave tega evropskega standarda. Drugi meroslovni standardi morda zajemajo področje uporabe, za katerega se uporablja tudi ta evropski standard.
Standard EN 50271 določa minimalne zahteve za aparate, ki uporabljajo programsko opremo in/ali digitalne komponente. Določa tudi dodatne izbirne zahteve za skladnost z ravnjo celovite varnosti 1 pri delovanju v načinu z nizkimi zahtevami. Standard EN 50402 zajema vse zahteve standarda EN 50271.
Standard EN 50402 se uporablja tudi za aparate in sisteme in/ali komponente za odkrivanje plina in naj bi se uporabljal namesto standarda EN 50271 v naslednjih primerih:
– pri ravni celovite varnosti 1, kadar sistem sestavljajo komponente, ki niso zajete v standardu EN 50271;
– pri ravni celovite varnosti 2 in 3;
– pri vseh ravneh celovite varnosti, če se uporablja nedigitalni aparat.
Uporaba zgoraj navedenih meroslovnih standardov bo zagotovila ustrezno učinkovitost merjenja pri običajnem delovanju sistema za odkrivanje plina. Poleg tega zahteve tega evropskega standarda obravnavajo funkcionalno varnost sistemov za odkrivanje plina in zajemajo kriterije za zanesljivost, toleriranje okvar ter preprečevanje sistematičnih okvar. Preprečevanje in nadzor sistematičnih okvar bodo zajemale zahteve za razvojne procese in tehnike ter diagnostične ukrepe, izbrane v času načrtovanja. Ta evropski standard bo privedel do karakterizacije sistema za odkrivanje plina z zmogljivostjo ravni celovite varnosti in s tem povezane stopnje okvar strojne opreme, s čimer bo predstavljal hierarhijo varnostnih ravni. To bo uporabniku omogočilo vključitev sistema za odkrivanje plina v celoten varnostni sistem v skladu s stopnjami varnostne celovitosti v standardu EN 61508 (vsi deli).
Ta evropski standard se uporablja za sisteme za odkrivanje plina, ki jih lahko sestavljajo naslednje funkcionalne enote:
– vzorčenje plina;
– senzor;
– prenos signala;
– vnosi v kontrolno enoto;
– obdelava signala v kontrolni enoti;
– izhod iz kontrolne enote.
Ta evropski standard ne določa zahtev za namestitev in vzdrževanje sistemov za odkrivanje plina. Ravno tako ne določa fizičnih položajev merilnih točk/mest.
Ta evropski standard ne določa, katera zmogljivost ravni celovite varnosti zadostuje za določen način uporabe.
OPOMBA 4: Zmogljivost ravni celovite varnosti za način uporabe določi uporabnik (glej točko 9 in dodatek A).
General Information
Relations
Overview
EN 50402:2017 - "Electrical apparatus for the detection and measurement of combustible or toxic gases or vapours or of oxygen - Requirements on the functional safety of gas detection systems" - is a European product standard focused on the functional safety of gas detection apparatus and systems. Based on EN 61508 (all parts), it defines requirements for low‑ and high‑demand modes with SIL-capabilities 1, 2 and 3 (SIL 4 is considered impracticable). The standard is primarily aimed at fixed gas detection equipment but can apply to portable detectors claiming SIL >1. It covers part of the safety lifecycle (phase 10 “realisation”) and addresses reliability, diagnostic measures, fault tolerance and avoidance of systematic failures.
Key topics and technical requirements
- SIL-capability and mapping: Procedures to determine SIL-capability for gas detection safety functions and transformation to EN 61508 safety integrity levels (Annex A, C).
- Modular characterization: Requirements and characterization for functional units such as:
- Gas sampling (aspiration, conditioning, multiplexer)
- Sensors (measuring principles and failure modes)
- Signal transmission and interfaces
- Input to control unit, signal processing, and output
- Hardware failure rates: Methods to determine hardware failure rates per safety function (Clause 8).
- Software requirements: Integrates and extends EN 61508‑3 software lifecycle expectations, with EN 50402‑specific levels of rigour and recommended techniques (Clause 6).
- Diagnostics & reduced modes: Requirements for diagnostics, automatic calibration/adjustment, reduced modes of operation, and special states.
- Documentation, validation and assessment: Functional safety management, validation, assessment and required documentation (Clauses 11–14).
- Scope limits: Does not cover installation, maintenance, or physical placement of detectors; configuration for specific applications is outside scope. In case of conflict with EN 61508, EN 50402 takes precedence.
Practical applications and who uses this standard
- Manufacturers of gas detectors and gas detection systems developing products with defined SIL-capabilities.
- Safety and reliability engineers specifying or verifying functional safety performance for industrial gas monitoring.
- System integrators and OEMs combining modules (sensors, samplers, control units) into safety functions.
- Asset owners, plant managers and procurement teams evaluating SIL-capable gas detection solutions for refineries, chemical plants, utilities and confined‑space monitoring.
- Certification bodies and testing labs performing compliance assessment against EN 50402 and related metrological standards.
Related standards
- EN 61508 (all parts) - Functional safety of electrical/electronic/programmable systems
- EN 50271 - Apparatus using software and/or digital components (EN 50402 includes EN 50271 requirements)
- Metrological standards (measurement performance): EN 60079‑29‑1, EN 60079‑29‑4 (flammable gases), EN 45544 (toxic gases), EN 50104 (oxygen)
- Note: EN 50402 supplements these metrological standards to address functional safety (reliability, diagnostics, systematic failure control).
EN 50402:2017 is essential for anyone designing, certifying or procuring gas detection systems where demonstrable SIL-capability, fault tolerance and documented functional safety are required.
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2017
1DGRPHãþD
SIST EN 50402:2005
SIST EN 50402:2005/A1:2008
(OHNWULþQHQDSUDYH]D]D]QDYDQMHLQPHUMHQMHJRUOMLYLKDOLVWUXSHQLKSOLQRYKODSRY
DOLNLVLND=DKWHYH]DIXQNFLRQDOQRYDUQRVWVLVWHPRY]DRGNULYDQMHSOLQD
Electrical apparatus for the detection and measurement of combustible or toxic gases or
vapours or of oxygen - Requirements on the functional safety of gas detection systems
Elektrische Geräte für die Detektion und Messung von brennbaren oder toxischen Gasen
und Dämpfen oder Sauerstoff - Anforderungen an die funktionale Sicherheit von
Gaswarnsystemen
Matériel électrique pour la détection et la mesure des gaz ou vapeurs combustibles ou
toxiques, ou de l'oxygène - Exigences relatives à la fonction de sécurité des systèmes de
détection de gaz
Ta slovenski standard je istoveten z: EN 50402:2017
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
13.320 Alarmni in opozorilni sistemi Alarm and warning systems
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN 50402
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2017
ICS 13.320 Supersedes EN 50402:2005
English Version
Electrical apparatus for the detection and measurement of
combustible or toxic gases or vapours or of oxygen -
Requirements on the functional safety of gas detection systems
Matériel électrique pour la détection et la mesure des gaz Elektrische Geräte für die Detektion und Messung von
ou vapeurs combustibles ou toxiques, ou de l'oxygène - brennbaren oder toxischen Gasen und Dämpfen oder
Exigences relatives à la fonction de sécurité des systèmes Sauerstoff - Anforderungen an die funktionale Sicherheit
de détection de gaz von Gaswarnsystemen
This European Standard was approved by CENELEC on 2017-02-04. CENELEC 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.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50402:2017 E
Contents Page
European foreword . 7
Introduction . 8
1 Scope . 10
2 Normative references . 11
3 Terms and definitions . 12
4 General requirements . 17
4.1 Specification of safety functions . 17
4.2 Determination of safety function . 23
4.3 Functional safety characteristics of modules . 24
5 Functional modules and elements — Characterization and requirements . 25
5.1 General . 25
5.1.1 Structure of functional modules . 25
5.1.2 General requirements . 29
5.2 Gas sampling . 30
5.2.1 Gas aspiration . 30
5.2.2 Conditioning of measured gas . 30
5.2.3 Gas multiplexer . 31
5.2.4 Gas sampling by diffusion mode . 31
5.2.5 Automatic calibration and adjustment . 31
5.3 Sensor . 32
5.4 Signal-transmission . 33
5.4.1 General requirements . 33
5.4.2 Signal-transmission between spatially separated modules . 33
5.4.3 Signal-transmission between modules not spatially separated . 35
5.5 Input to signal processing . 36
5.5.1 General . 36
5.5.2 Interface for measured signal . 36
5.5.3 Input system communication . 36
5.5.4 User interface . 36
5.5.5 Input from periphery . 37
5.5.6 Power supply . 37
5.6 Signal processing . 37
5.6.1 General . 37
5.6.2 Calculation of measured values . 39
5.6.3 Special state . 39
5.6.4 Signal assessment . 40
5.6.5 Diagnostic means within a control unit . 41
5.6.6 Reduced mode of operation . 43
5.6.7 Aspiration control . 44
5.6.8 Gas multiplexer control . 44
5.6.9 Control of automatic calibration . 44
5.6.10 Control of automatic adjustment . 45
5.7 Output of the control . 45
5.7.1 Visual indication . 45
5.7.2 Switching output . 46
5.7.3 Output system communication . 47
5.7.4 Output to periphery . 48
5.7.5 Data archives . 48
6 Software . 49
6.1 General requirements . 49
6.2 Context of the Software Standard . 49
6.3 Requirements from EN 61508-3 . 49
6.4 List of replaced or not relevant clauses in EN 61508-3:2010 . 50
6.5 List of changes to clauses in EN 61508-3 . 51
6.6 EN 50402 Levels of rigour . 54
6.7 Tables of techniques and measures from EN 61508-3:2010, Annex A . 55
6.7.1 Explanation of terms . 55
6.7.2 Writing conventions in the tables of techniques and measures . 55
6.7.3 Software requirements specification . 55
6.7.4 Software architecture design . 58
6.7.5 Software design and development – Support tools and programming language . 62
6.7.6 Software detailed design . 62
6.7.7 Software module testing and integration. 65
6.7.8 PE integration (hardware + software) . 67
6.7.9 Software validation . 68
6.7.10 Modification . 69
6.7.11 Software Verification . 70
7 Combining Functional Modules to Safety Functions . 72
7.1 SIL-capability . 72
7.2 Determination of SIL-capabilities for a safety function . 73
7.2.1 General . 73
7.2.2 Summarizing of single chains . 74
7.2.3 Summarizing of parallel chains . 74
8 Determination of hardware failure rates for each safety function . 75
9 Gas detection as part of an overall safety function . 76
10 Information requirements . 77
11 Validation . 78
12 Functional safety management . 79
13 Functional safety assessment . 79
14 Documentation . 79
Annex A (normative) Transformation of the SIL-capabilities of gas detection systems . 80
A.1 Introduction . 80
A.2 Transformation of the SIL-capabilities of gas detection systems to the safety integrity
levels of EN 61508 (all parts) . 80
Annex B (normative) Transformation from generic standard requirements to modules . 81
B.1 General . 81
B.2 SIL-capability 1 . 81
B.3 SIL-capability 2 . 81
B.4 SIL-capability 3 . 82
Annex C (informative) Determination of SIL-capability of a safety function of the gas detection
system . 83
C.1 General . 83
C.2 Procedure of determination of SIL-capability . 83
C.3 Example: Determination of SIL-capability for a gas detection system . 89
C.3.1 General . 89
C.3.2 Example: Characterization of relay outputs of control units A and B . 89
C.3.3 Example: Characterization of relay output of common alarm . 91
Annex D (informative) Failure modes for specific measuring principles . 93
D.1 Introduction . 93
D.2 Failure modes relevant to most or all types of measuring principles and types of sensing
elements . 93
D.2.1 Generic failure modes . 93
D.2.2 Failure modes identified in the metrological standards. 93
D.3 Catalytic sensing elements . 94
D.4 Thermal conductivity sensing elements . 94
D.5 Infrared sensing elements . 94
D.5.1 Point detectors . 94
D.5.2 Open path detectors . 95
D.5.3 TDLAS (e.g. for oxygen). 95
D.6 Semiconductor sensing elements . 95
D.7 Electrochemical sensing elements . 95
D.7.1 Galvanic — Lead based oxygen . 95
D.7.2 Amperometric with organic or aqueous electrolyte . 96
D.8 FID sensing elements. 96
D.9 FTA sensing elements . 96
D.10 Paramagnetic sensing elements . 97
D.10.1 General . 97
D.10.2 Principle using a dumbbell . 97
D.10.3 Microflow Measuring Principle . 97
D.10.4 Measurement of magnetic susceptibility . 98
D.10.5 Paramagnetic thermal effect . 98
D.11 PID sensing elements . 98
Figures
Figure 1 — Definitions of measuring point, measuring group and measuring location. 14
Figure 2a — Gas detection system plus actuator for safety function . 18
Figure 2b — Gas detection system plus actuator for safety function . 19
Figure 2c — Gas detector with relay output plus actuator for safety function . 20
Figure 2d — Gas detection system plus actuator for safety function . 20
Figure 2e — Gas detection system plus actuator for safety function . 21
Figure 2f — Gas detection system plus actuator for safety function . 22
Figure 2 — Examples for the overall safety function of gas detection systems . 22
Figure 3 — Overview of safety-related system . 26
Figure 4 — Modules of a gas detection system . 28
Figure 5 — Architectures for data communication . 35
Figure 6 — Single and parallel chains . 73
Figure 7 — Handling of complex modules in a redundant structure . 75
Figure C.1 — Step 1 – Linkage of modules. 83
Figure C.2 — Step 2 – Identification of modules necessary for the safety function . 84
Figure C.3 — Step 3 – Elimination of modules and linkages without influence on the safety
function . 84
Figure C.4 — Step 4 (1st loop) – Summarizing of single chains . 84
Figure C.5 — Step 5 (1st loop) – Summarizing of parallel chains . 85
Figure C.6 — Step 6 (1st loop) – Adaptation of block diagram structure . 87
Figure C.7 — Step 4 (2nd loop) – Summarizing of single chains . 87
Figure C.8 — Step 5 (2nd loop) – Summarizing of parallel chains . 87
Figure C.9 — Step 6 (2nd loop) – Adaptation of block diagram structure – No action required . 88
Figure C.10 — Step 4 (3rd loop) – Summarizing of single chains . 88
Figure C.11 — Step 5 (3rd loop) – Summarizing of parallel chains . 88
Figure C.12 — Step 6 (3rd loop) – Adaptation of block diagram structure – No action required . 88
Figure C.13 — Step 4 (4th loop) – Summarizing of single chains – End of procedure . 89
Figure C.14 — Step 1 – Linkages between modules for the example . 89
Figure C.15 — Step 2 – Identification of modules with influence on the safety function . 90
Figure C.16 — Step 3 – Elimination of modules and linkages without influence on the safety
function . 90
Figure C.17 — Step 4 – Summarizing of single chains . 90
Figure C.18 — Step 5 – Summarizing of parallel chains – End of procedure . 90
Figure C.19 — Step 2 – Identification of modules with influence on the safety function . 91
Figure C.20 — Step 3 – Elimination of modules and linkages without influence on the safety
function . 91
Figure C.21 — Step 4 (1st loop) – Summarizing of single chains . 92
Figure C.22 — Step 5 (1st loop) – Summarizing of parallel chains . 92
Figure C.23 — Step 6 (1st loop) – Adaptation of block diagram structure – No action required . 92
Figure C.24 — Step 4 (2nd loop) – Summarizing of single chains – End of procedure . 92
Tables
Table 1 — Fault tolerance for simple modules according to EN 61508–2:2010, (Table 2) . 24
Table 2 — Fault tolerance for complex modules according to EN 61508–2:2010, (Table 3) . 25
Table 3 — Diagnostic measures for program sequence monitoring and clock from EN 61508–2 . 41
Table 4 — Diagnostic measures for memory from EN 61508–2 . 42
Table 5 — List of replaced or not relevant clauses in EN 61508–3:2010 . 50
Table 6 — List of changes to clauses in EN 61508–3:2010 . 51
Table 7 — EN 50402 levels of rigour . 54
Table 8 — EN 50402 software requirements specification (from EN 61508–3:2010, Table A.1) . 55
Table 9 — Semi formal and formal methods (from EN 61508–3:2010, Table B.7) as applied to
Table A.1 . 57
Table 10 — EN 50402 software architecture design (from EN 61508–3:2010, Table A.2) . 58
Table 11 — EN 50402 software design (from EN 61508–3:2010, Table A.3) . 62
Table 12 — EN 50402 software detailed design (from EN 61508–3:2010, Table A.4) . 62
Table 13 — Semi-formal methods (EN 61508–3:2010, Table B.7) as applied to Table A.4 . 64
Table 14 — EN 50402 software module testing and integration (from EN 61508–3:2010, Table A.5) . 65
Table 15 — EN 50402 PE integration (hardware + software) (from EN 61508–3:2010, Table A.6) . 67
Table 16 — EN 50402 software validation (from EN 61508–3:2010, Table A.7) . 68
Table 17 — EN 50402 modification (from EN 61508–3:2010, Table A.8) . 69
Table 18 — EN 50402 software verification (from EN 61508–3:2010, Table A.9) . 70
Table 19 — For low demand mode of operation (see EN 61508–1:2010, 7.6.2.9, Table 2) . 76
Table 20 — For high demand mode of operation or continuous mode of operation
(see EN 61508–1:2010, 7.6.2.9, Table 3) . 76
Table A.1 — Transformation of the SIL-capabilities of EN 50402 to SIL of EN 61508 (all parts) . 80
Table C.1 — Determination of SIL-capability for a parallel chain block (applicable for hardware
only) . 86
European foreword
This document (EN 50402:2017) has been prepared by CLC/SC 31-9 “Electrical apparatus for the detection
and measurement of combustible gases to be used in industrial and commercial potentially explosive
atmospheres” of CLC/TC 31 “Electrical apparatus for potentially explosive atmospheres” and by CLC/TC 216
“Gas detectors”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2018-02-04
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2020-02-04
conflicting with this document have to
be withdrawn
This document supersedes EN 50402:2005.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
— In general, the standard is updated to consider the modifications in the second edition of EN 61508 for
hardware and software. Route 2 of the second edition of EN 61508 will not be permitted for gas detection
equipment.
— The standard is updated for the SIL 1 requirements to be in line with the second edition of EN 50271
specifying the minimum requirements for functional safety for performance approved gas detectors, gas
detection apparatus and complete gas detection systems.
— The latest revisions of the metrological standards have been considered.
— SIL 4 has been deleted as being not appropriate to gas detection.
— Clauses 4 and 5 have been updated for more detailed specification.
— Clause 6 for software is new.
— Clauses 7 to 11 are restructured for clarification of requirements and relation to EN 61508.
— Clause 10 is specifying more details for the customer information.
— The former normative Annex D is now Clause 12.
— The former informative Annex A has been deleted. Relevant text was moved to Clauses 7 to 9.
— The new informative Annex D is providing information on failure modes of sensing elements.
Introduction
This European Standard specifies requirements for the functional safety of gas detection systems. It
encompasses criteria for reliability, avoidance of faults and fault tolerance. Functional safety is that part of the
overall safety which relates specifically to the measures required within the gas detection system to avoid or to
handle failures so that the safety function is ensured. This includes not only design and the development
process requirements of the gas detection system but also the information requirements for planning, putting
into operation, maintenance and repair.
This European Standard is dedicated to the manufacturer. Information important for the safe use of the device
(gas detection system) will be specified in the instruction manual.
Gas detection systems will fail to function if dangerous failures occur in the equipment used. Failure to
function will also occur if such systems are not installed or maintained in an appropriate manner. In some
applications, failures of this type will dominate the functional safety achieved. This European Standard is only
targeted at reducing equipment failures to levels appropriate to the application. Users of gas detection
systems will therefore need to ensure installation and maintenance of such systems is carried out according to
the instruction manual. This European Standard does not specify the physical positioning of measuring points
/ locations.
Gas detection systems may differ widely in structure, complexity and performance. They may not be handled
in a uniform manner like low complexity devices, for this reason a general specification of requirements is not
possible.
Gas detection systems therefore need to be divided into functional modules for validation to ensure that
systems which have different structures are handled according to appropriate procedures. A gas detection
system will not normally include all the modules covered by this European Standard. Requirements are
specified for each of these modules in terms of hierarchical levels which represent one of the constituents of
functional safety performance. The hierarchical levels are termed as SIL-capabilities, with SIL-capability 1
representing the minimum and SIL-capability 3 the maximum levels of functional safety to comply with this
European Standard. The SIL-capability of a module is related to the maximum safety integrity level that may
be claimed for a safety function which uses modules of that specified SIL-capability. Modules will be
characterized in terms of their SIL-capability. Information is also required on failure rate characteristics of
modules or related physical components to enable the manufacturer to determine the overall level of
functional safety of a gas detection system. In this way, the manufacturer will take account of both random
failures of hardware components and systematic failures in hardware and software. This European Standard
also specifies the requirements that will enable determination of whether the gas detection system has a low
enough failure rate when used in conjunction with other equipment necessary for functional safety.
This European Standard will enable the functional safety characteristics of the gas detection system to be
determined from the characteristics of its modules and components (see Annex C). This will enable a gas
detection system to be used as a part of an overall safety system. The characterization including the
determination of a SIL-capability and failure rate data will only need to be carried out once for a particular
module or component.
Depending on characterization of each module and component, the properties of each chosen safety function
of the whole gas detection system will be specified. The procedure for determining the SIL-capability of a
safety function of a gas detection system will only need to be repeated for each new combination of modules
and components. Different combinations of equivalent modules may lead to gas detection systems which
reach different SIL-capabilities.
In this way a flexible adoption of the gas detection system into different applications will be possible without
repeating all steps of the validation procedure for every new configuration.
This European Standard does not include requirements for availability which will need to be considered
separately.
This European Standard is dedicated to manufacturers and is applicable to gas detection systems or parts of
them (e.g. gas detection transmitters or gas detection control units) as basis for functional safety testing. It
supplements the requirements of the relevant metrological standards. It should not be confused with
EN 60079–29–3 which is dedicated to system integrators to give guidance for combining gas detection
apparatus with other equipment (e.g. gas processing, filters, valves) not provided by the gas detection
manufacturer but part of a safety function under the responsibility of the system integrator.
1 Scope
This European Standard is applicable to detection and measurement apparatus and systems for flammable or
toxic gases or vapours or oxygen. It covers apparatus intended to measure reliably, gas concentration and to
provide an output signal (alarm and/or measurement signal), the purpose of which is to give a warning of a
potential hazard.
This European Standard is a product standard which is based on EN 61508 (all parts) and for gas detection
systems covers both low and high demand mode at SIL capabilities of 1, 2 or 3 only. Gas detection apparatus
and gas detection systems are developed as generic products. This European Standard covers part of the
phase 10 “realization” of the overall safety lifecycle defined in EN 61508-1:2010, Figure 2. Configuration and
integration into specific applications is not covered by this European Standard.
In the event of conflict between the requirements of this European Standard and those of EN 61508,
EN 50402 will take precedence.
NOTE 1 Applications requiring a SIL capability of 4 for a gas detection system are not practicable.
This European Standard is dedicated mainly to fixed apparatus and systems. However, it can also be applied
to transportable gas detectors which are intended to be used as temporary replacements for fixed apparatus.
This European Standard supplements the requirements of the European Standards for electrical apparatus for
the detection and measurement of flammable gases, vapours (e.g. EN 60079-29-1 or EN 60079-29-4), toxic
gases (e.g. EN 45544) or oxygen (e.g. EN 50104).
NOTE 2 These European Standards are called in the text “metrological standards”.
The examples above show the state of the standardization for industrial applications at the time of publishing
this European Standard. There may be other metrological standards covering other application fields, for
which this European Standard is also applicable.
EN 50271 specifies minimum requirements for apparatus using software and/or digital components. It also
defines additional optional requirements for compliance with SIL 1 in low demand mode operation. EN 50402
includes all requirements of EN 50271.
EN 50402 is also dedicated to apparatus and gas detection systems and/or components and should be used
instead of EN 50271 in the following cases:
— at SIL 1 when the system contains components not covered by EN 50271;
— at SIL 1 high demand mode operation;
— at SIL 2 and SIL 3;
— at all SILs when non-digital based apparatus is used.
Applying the above-mentioned metrological standards will ensure the performance is adequate in normal
operation of a gas detection system. Additionally, the requirements of this European Standard address the
functional safety of gas detection systems and encompass criteria for reliability, fault tolerance and avoidance
of systematic failures. The avoidance and control of systematic failures will be covered by the requirements for
the development processes and techniques and diagnostic measures chosen in the design. This European
Standard will lead to the characterization of the gas detection system by a SIL-capability and related hardware
failure rate representing a hierarchical order of safety levels. This will allow the user to incorporate the gas
detection system into an overall safety system according to the safety integrity levels of EN 61508 (all parts).
This European Standard is applicable for gas detection systems, which may consist of the following functional
units:
— gas-sampling;
— sensor;
— signal transmission;
— input to control unit;
— signal processing in control unit;
— output from control unit.
This European Standard does not specify requirements for the installation and maintenance of gas detection
systems. It also does not specify the physical positioning of measuring points / locations.
This European Standard does not specify which SIL-capability is sufficient for which application.
NOTE 3 The SIL-capability required for an application will be specified by the user (see Clause 9 and Annex A).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 45544-1, Workplace atmospheres — Electrical apparatus used for the direct detection and direct
concentration measurement of toxic gases and vapours — Part 1: General requirements and test methods
EN 45544-2, Workplace atmospheres — Electrical apparatus used for the direct detection and direct
concentration measurement of toxic gases and vapours — Part 2: Performance requirements for apparatus
used for exposure measurement
EN 45544-3, Workplace atmospheres — Electrical apparatus used for the direct detection and direct
concentration measurement of toxic gases and vapours — Part 3: Performance requirements for apparatus
used for general gas detection
EN 45544-4, Workplace atmospheres — Electrical apparatus used for the direct detection and direct
concentration measurement of toxic gases and vapours — Part 4: Guide for selection, installation, use and
maintenance
EN 50104, Electrical apparatus for the detection and measurement of oxygen - Performance requirements
and test methods
EN 50159, Railway applications - Communication, signalling and processing systems - Safety-related
communication in transmission systems
EN 50270, Electromagnetic compatibility — Electrical apparatus for the detection and measurement of
combustible gases, toxic gases or oxygen
EN 50271:2010, Electrical apparatus for the detection and measurement of combustible gases, toxic gases or
oxygen - Requirements and tests for apparatus using software and/or digital technologies
EN 60079-29-1:2016, Explosive atmospheres - Part 29-1: Gas detectors - Performance requirements of
detectors for flammable gases (IEC 60079-29-1:2016)
EN 60079-29-2, Explosive atmospheres — Part 29-2: Gas detectors — Selection, installation, use and
maintenance of detectors for flammable gases and oxygen (IEC 60079-29-2)
EN 60079-29-3, Explosive atmospheres - Part 29-3: Gas detectors - Guidance on functional safety of fixed
gas detection systems (IEC 60079-29-3)
EN 60079-29-4, Explosive atmospheres - Part 29-4: Gas detectors - Performance requirements of open path
detectors for flammable gases (IEC 60079-29-4)
EN 61326-3-1, Electrical equipment for measurement, control and laboratory use - EMC requirements - Part
3-1: Immunity requirements for safety-related systems and for equipment intended to perform safety-related
functions (functional safety) - General industrial applications
EN 61326-3-2, Electrical equipment for measurement, control and laboratory use — EMC requirements —
Part 3-2: Immunity requirements for safety-related systems and for equipment intended to perform safety-
related functions (functional safety) — Industrial applications with specified electromagnetic environment (IEC
61326-3-2)
EN 61508-1:2010, Functional safet
...
Frequently Asked Questions
EN 50402:2017 is a standard published by CLC. Its full title is "Electrical apparatus for the detection and measurement of combustible or toxic gases or vapours or of oxygen - Requirements on the functional safety of gas detection systems". This standard covers: This European Standard is applicable to apparatus and systems for the detection and measurement of flammable or toxic gases or vapours or oxygen. This European Standard is a product standard which is based on EN 61508 (all parts) and for gas detection systems covers both low and high demand mode at SIL capabilities of 1, 2 or 3 only. Gas detection apparatus and gas detection systems are developed as generic products. This standard covers part of the phase 10 “realisation” of the overall safety lifecycle defined in Figure 2 of EN 61508-1:2010. Configuration and integration into specific applications is not covered by this standard. In the event of conflict between the requirements of this standard and those of EN 61508, EN 50402 will take precedence. NOTE 1 Applications requiring a SIL capability of 4 for a gas detection system are not practicable. NOTE 2 This European Standard is dedicated mainly to fixed apparatus. For portable gas detectors claiming a SIL higher than 1, this European Standard may be applied. This European Standard supplements the requirements of the European Standards for electrical apparatus for the detection and measurement of flammable gases, vapours (e.g. EN 60079-29-1 or EN 60079-29-4), toxic gases (e.g. EN 45544) or oxygen (e.g. EN 50104). NOTE 3 These European Standards are called in the text "metrological standards". The examples above show the state of the standardisation for industrial applications at the time of publishing this European Standard. There may be other metrological standards covering other application fields, for which this European Standard is also applicable. EN 50271 specifies minimum requirements for apparatus using software and/or digital components. It also defines additional optional requirements for compliance with SIL 1 in low demand mode operation. EN 50402 includes all requirements of EN 50271. EN 50402 is also dedicated to apparatus and gas detection systems and/or components and should be used instead of EN 50271 in the following cases: - At SIL 1 when the system contains components not covered by EN 50271; - At SIL 2 and SIL 3; - At all SILs when non-digital based apparatus is used. Applying the above-mentioned metrological standards will ensure the measuring performance is adequate in normal operation of a gas detection system. Additionally the requirements of this European Standard address the functional safety of gas detection systems and encompass criteria for reliability, fault tolerance and avoidance of systematic failures. The avoidance and control of systematic failures will be covered by the requirements for the development processes and techniques and diagnostic measures chosen in the design. This European Standard will lead to the characterisation of the gas detection system by a SIL-capability and related hardware failure rate representing a hierarchical order of safety levels. This will allow the user to incorporate the gas detection system into an overall safety system according to the safety integrity levels of EN 61508 (all parts). This European Standard is applicable for gas detection systems, which may consist of the following functional units: - gas-sampling; - sensor; - signal transmission; - input to control unit; - signal processing in control unit; - output from control unit. This European Standard does not specify requirements for the installation and maintenance of gas detection systems. It also does not specify the physical positioning of measuring points / locations. This European Standard does not specify which SIL-capability is sufficient for which application. NOTE 4 The SIL-capability required for an application will be specified by the user (see Clause 9 and Annex A ).
This European Standard is applicable to apparatus and systems for the detection and measurement of flammable or toxic gases or vapours or oxygen. This European Standard is a product standard which is based on EN 61508 (all parts) and for gas detection systems covers both low and high demand mode at SIL capabilities of 1, 2 or 3 only. Gas detection apparatus and gas detection systems are developed as generic products. This standard covers part of the phase 10 “realisation” of the overall safety lifecycle defined in Figure 2 of EN 61508-1:2010. Configuration and integration into specific applications is not covered by this standard. In the event of conflict between the requirements of this standard and those of EN 61508, EN 50402 will take precedence. NOTE 1 Applications requiring a SIL capability of 4 for a gas detection system are not practicable. NOTE 2 This European Standard is dedicated mainly to fixed apparatus. For portable gas detectors claiming a SIL higher than 1, this European Standard may be applied. This European Standard supplements the requirements of the European Standards for electrical apparatus for the detection and measurement of flammable gases, vapours (e.g. EN 60079-29-1 or EN 60079-29-4), toxic gases (e.g. EN 45544) or oxygen (e.g. EN 50104). NOTE 3 These European Standards are called in the text "metrological standards". The examples above show the state of the standardisation for industrial applications at the time of publishing this European Standard. There may be other metrological standards covering other application fields, for which this European Standard is also applicable. EN 50271 specifies minimum requirements for apparatus using software and/or digital components. It also defines additional optional requirements for compliance with SIL 1 in low demand mode operation. EN 50402 includes all requirements of EN 50271. EN 50402 is also dedicated to apparatus and gas detection systems and/or components and should be used instead of EN 50271 in the following cases: - At SIL 1 when the system contains components not covered by EN 50271; - At SIL 2 and SIL 3; - At all SILs when non-digital based apparatus is used. Applying the above-mentioned metrological standards will ensure the measuring performance is adequate in normal operation of a gas detection system. Additionally the requirements of this European Standard address the functional safety of gas detection systems and encompass criteria for reliability, fault tolerance and avoidance of systematic failures. The avoidance and control of systematic failures will be covered by the requirements for the development processes and techniques and diagnostic measures chosen in the design. This European Standard will lead to the characterisation of the gas detection system by a SIL-capability and related hardware failure rate representing a hierarchical order of safety levels. This will allow the user to incorporate the gas detection system into an overall safety system according to the safety integrity levels of EN 61508 (all parts). This European Standard is applicable for gas detection systems, which may consist of the following functional units: - gas-sampling; - sensor; - signal transmission; - input to control unit; - signal processing in control unit; - output from control unit. This European Standard does not specify requirements for the installation and maintenance of gas detection systems. It also does not specify the physical positioning of measuring points / locations. This European Standard does not specify which SIL-capability is sufficient for which application. NOTE 4 The SIL-capability required for an application will be specified by the user (see Clause 9 and Annex A ).
EN 50402:2017 is classified under the following ICS (International Classification for Standards) categories: 13.320 - Alarm and warning systems. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 50402:2017 has the following relationships with other standards: It is inter standard links to EN 50402:2005, EN 50402:2005/A1:2008. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase EN 50402:2017 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of CLC standards.
EN 50402:2017 is a European Standard that applies to apparatus and systems for detecting and measuring flammable or toxic gases, vapors, or oxygen. It is based on EN 61508 and covers both low and high demand modes for gas detection systems with SIL capabilities of 1, 2, or 3. This standard does not cover configuration and integration into specific applications. In case of conflict with EN 61508, EN 50402 takes precedence. It should be noted that gas detection systems with a SIL capability of 4 are not practical. This standard mainly applies to fixed apparatus, but can also be applied to portable gas detectors with SIL higher than 1. EN 50402 complements other European standards for electrical apparatus for gas detection. It specifies requirements for software and/or digital components and covers both digital and non-digital based apparatus. It ensures reliable and safe operation of gas detection systems, addressing reliability, fault tolerance, and avoidance of systematic failures. The standard allows for the characterization of gas detection systems by SIL capability and hardware failure rate, allowing users to incorporate them into overall safety systems. The standard defines the functional units of gas detection systems, but does not specify installation, maintenance, or SIL requirements for specific applications. The SIL capability requirement is determined by the user.
EN 50402:2017は、可燃性または有毒なガスや蒸気、酸素を検出し、測定するための装置およびシステムに適用される欧州規格です。この規格はEN 61508に基づいた製品規格であり、ガス検知システムについてはSIL能力が1、2、または3の低需要モードと高需要モードの両方をカバーしています。ガス検知装置やガス検知システムは一般的な製品として開発されます。この規格はEN 61508-1:2010の図2で定義された安全寿命サイクルのフェーズ10「実現」の一部をカバーしています。設定や特定のアプリケーションへの統合はこの規格ではカバーされていません。この規格とEN 61508の要件が競合する場合、EN 50402が優先されます。注意1：ガス検知システムにSIL能力4が必要なアプリケーションは実用的ではありません。注意2：この欧州規格は主に固定装置に適用されますが、SIL値が1以上のポータブルガス検知器にも適用される場合があります。この規格は可燃性ガス、蒸気（例：EN 60079-29-1またはEN 60079-29-4）、有毒ガス（例：EN 45544）または酸素（例：EN 50104）の検出および測定のための電気機器の欧州規格の要件を補完します。注意3：これらの欧州規格は「計測規格」として本文中で呼ばれています。上記の例は、本欧州規格が公開された時点での産業応用の標準化状況を示しています。同様の本欧州規格が適用される他の応用分野には、他の計測規格が存在する場合があります。EN 50271はソフトウェアやデジタル部品を使用する装置に対する最低要件および低需要モード運転でSIL 1に準拠するための追加の任意要件を規定しています。EN 50402はEN 50271のすべての要件を含んでおり、次の場合にEN 50271の代わりに使用されます。- EN 50271に含まれていない要素がシステムに含まれている場合、SIL 1の場合、- SIL 2およびSIL 3の場合、-非デジタルベースの装置が使用される場合、すべてのSILで。上記の計測規格の適用により、ガス検知システムの正常な運転で適切な計測性能が確保されます。また、この欧州規格の要件は、ガス検知システムの機能的な安全性、信頼性、障害耐性、システム的な故障の回避に関する基準を包括しています。システム的な故障の防止および制御は、設計で選択された開発プロセス、技術、および診断手法の要件によって対処されます。この欧州規格により、ガス検知システムのSIL能力と関連するハードウェアの故障率によって、システムの階層的な安全レベルを示すことができます。この欧州規格は、次の機能単位で構成されるガス検知システムに適用されます。-ガスサンプリング；-センサー；-信号転送；-制御ユニットへの入力；-制御ユニットによる信号処理；-制御ユニットからの出力。この欧州規格は、ガス検知システムの設置および保守要件を規定しておらず、計測ポイントや位置の指定も行いません。この欧州規格は、どのSIL能力がどのアプリケーションに適しているかを特定しません。注意4：アプリケーションに必要なSIL能力は、ユーザーによって指定されます。（条項9および付属書Aを参照）。
EN 50402:2017 is a European standard that specifies requirements for the functional safety of apparatus and systems used to detect and measure combustible or toxic gases or vapors, as well as oxygen. It is based on EN 61508 and covers both low and high demand modes with SIL capabilities of 1, 2, or 3. The standard addresses the development of gas detection systems as generic products and is part of the overall safety lifecycle. It does not cover configuration and integration into specific applications. In case of conflict with EN 61508, EN 50402 takes precedence. The standard is mainly focused on fixed apparatus but may also apply to portable gas detectors claiming a SIL higher than 1. It complements other European standards for electrical apparatus used in gas detection. EN 50402 includes all requirements of EN 50271 and is used in cases where components not covered by EN 50271 are present, or when SIL 2 and SIL 3 are required, or when non-digital-based apparatus is used. The standard ensures adequate measuring performance and addresses functional safety, including criteria for reliability, fault tolerance, and avoidance of systematic failures. It helps characterize the gas detection system by its SIL capability and related hardware failure rate. The standard does not cover installation and maintenance requirements or specify the positioning of measuring points. The required SIL capability for an application is determined by the user.
EN 50402:2017은 가연성 또는 유독한 가스 또는 증기 또는 산소를 감지하고 측정하기 위한 장치 및 시스템에 적용되는 유럽 표준이다. 이 유럽 표준은 EN 61508을 기반으로 하고 있으며, 가스 감지 시스템의 저 부하 및 고 부하 모드에 대한 SIL 능력 1, 2 또는 3만을 다룬다. 가스 감지 장치와 가스 감지 시스템은 일반적인 제품으로 개발된다. 이 표준은 EN 61508-1:2010의 도표 2에 정의된 전반적인 안전 수명주기의 실현 단계 10의 일부를 다룬다. 구성 및 특정 응용프로그램으로 통합하는 것은 이 표준에 포함되지 않는다. 이 표준과 EN 61508의 요구 사항간에 충돌이 있는 경우, EN 50402가 우선한다. 참고 1 : SIL 능력 4가 필요한 응용은 현실적으로 불가능하다. 참고 2 : 이 유럽 표준은 주로 고정 장치에 해당한다. SIL 1 이상을 요구하는 휴대용 가스 검출기에는 이 유럽 표준이 적용될 수 있다. 이 유럽 표준은 가연성 가스, 증기(예: EN 60079-29-1 또는 EN 60079-29-4), 유독 가스 (예: EN 45544) 또는 산소 (예: EN 50104)의 감지 및 측정을 위한 전기 장치의 유럽 표준의 요구 사항을 보완한다. 참고 3 : 이 유럽 표준은 본문에서 "계측 표준"이라고 불린다. 위의 예는 이 유럽 표준이 발행되는 시점에서 산업 응용 프로그램에 대한 표준화 상태를 보여준다. 이 외에도 이 유럽 표준이 적용될 수 있는 다른 응용 분야를 다룰 수 있는 다른 계측 표준이 있을 수 있다. EN 50271은 소프트웨어 및 / 또는 디지털 구성 요소를 사용하는 장치에 대한 최소 요구 사항을 지정한다. 또한 저 부하 모드 운영에서 SIL 1 준수를 위한 추가 선택 요구 사항을 정의한다. EN 50402에는 EN 50271의 모든 요구 사항이 포함되어 있다. EN 50402는 장치와 가스 감지 시스템 및 / 또는 구성 요소에 전용되어 있으며 다음 경우에는 EN 50271 대신 사용해야 한다. - EN 50271에 포함되지 않은 구성 요소가 시스템에 있을 때 SIL 1에서; - SIL 2 및 SIL 3에서; - 비디지털 기반 장치가 사용될 때 모든 SIL에 대해. 상기한 계측 표준을 적용하면 가스 감지 시스템의 정상 작동에서 충분한 측정 성능을 보장한다. 이 유럽 표준의 요구 사항은 가스 감지 시스템의 기능적 안전을 다루며 신뢰성, 장애 허용력 및 시스템적인 결함의 방지에 대한 기준을 포함한다. 시스템적인 결함의 방지와 제어 방법은 설계에서 선택된 개발 프로세스, 기술 및 진단 조치의 요구 사항으로 다룬다. 이 유럽 표준은 가스 감지 시스템을 EN 61508 (모든 부분)의 안전 무결성 수준에 따라 전체 안전 시스템에 통합할 수 있도록 SIL 능력과 관련된 하드웨어 장애률로 가스 감지 시스템을 특징지어 준다. 이 유럽 표준은 다음 기능 단위로 구성될 수 있는 가스 감지 시스템에 적용된다. - 가스 샘플링; - 센서; - 신호 전송; - 제어 장치로의 입력; - 제어 장치의 신호 처리; - 제어 장치의 출력. 이 유럽 표준은 가스 감지 시스템의 설치와 유지 보수 요구 사항을 규정하지 않으며, 측정 지점 또는 위치 요구 사항을 명시하지 않는다. 이 유럽 표준은 어떤 SIL 능력이 어떤 응용에 충분한지를 규정하지 않는다. 참고 4 : 응용 프로그램에 필요한 SIL 능력은 사용자에 의해 지정된다. (Clause 9 및 Annex A 참조).
EN 50402:2017は、可燃性または有毒なガスや蒸気、酸素を検出および測定するための装置およびシステムに適用される欧州規格です。この規格はEN 61508（すべての部分）に基づく製品規格であり、ガス検出システムにおいてSIL能力が1、2、または3の低需要モードおよび高需要モードをカバーしています。ガス検知装置およびガス検知システムは、一般的な製品として開発されます。この規格は、EN 61508-1:2010の図2で定義された全体的な安全ライフサイクルの段階10「達成」の一部をカバーします。この規格では、具体的なアプリケーションへの構成および統合はカバーされていません。この規格とEN 61508の要件が衝突する場合、EN 50402が優先されます。注1：ガス検知システムのSIL能力が4であるようなアプリケーションは実現不可能です。注2：この規格は主に固定装置に適用されますが、SILが1を超える携帯型ガス検知器にも適用される場合があります。この欧州規格は、可燃性ガス、蒸気（例：EN 60079-29-1またはEN 60079-29-4）、有毒ガス（例：EN 45544）、または酸素（例：EN 50104）の電気装置に関する欧州規格の要件を補完します。注3：これらの欧州規格は「計量規格」としてテキスト内で呼ばれます。上記の例は、この欧州規格の発行時における産業用途における標準化の状況を示しています。他の応用分野にも適用可能な他の計量規格が存在する場合があります。EN 50271はソフトウェアおよび/またはデジタルコンポーネントを使用する装置に対する最低要件を規定します。また、低需要モードの動作においてSIL 1に準拠するための追加のオプショナル要件を定義します。EN 50402にはEN 50271のすべての要件が含まれています。EN 50402は設備およびガス検知システムおよび/またはコンポーネントに専用され、以下の場合にEN 50271の代わりに使用されるべきです：-EN 50271でカバーされていないコンポーネントを含むシステムでSIL 1の場合。-SIL 2およびSIL 3の場合。-非デジタルベースの装置が使用される場合のすべてのSIL。上記の計量規格を適用することで、ガス検知システムの正常動作時の測定性能が適切であることが保証されます。また、この欧州規格の要件は、ガス検知システムの機能的安全性に対応し、信頼性、障害許容性、および系統的な故障回避の基準を含みます。系統的な故障の回避と制御は、設計において選択された開発プロセス、技術、および診断措置によってカバーされます。この欧州規格によって、ガス検知システムはSIL能力と関連するハードウェアの故障率によって特徴付けられ、EN 61508（すべての部分）の安全完全性レベルに応じて総合的な安全システムに組み込むことができます。この欧州規格は、ガス検知システムに適用される以下の機能ユニットを対象とします：-ガスサンプリング；-センサー；-信号伝送；-制御ユニットへの入力；-制御ユニットでの信号処理；-制御ユニットからの出力。この欧州規格は、ガス検知システムの設置および保守の要件を規定していません。また、測定ポイント/場所の物理的配置も規定していません。この欧州規格は、どのSIL能力が特定の応用に適しているかを規定していません。注4：応用のSIL能力要件は、ユーザーによって指定されます（第9節および付録Aを参照）。
EN 50402:2017은 인화성 또는 독성 가스, 증기 또는 산소를 탐지하고 측정하는 기기 및 시스템에 적용되는 유럽 표준입니다. 이 표준은 EN 61508(모든 부분)에 기반한 제품 표준으로, 가스 탐지 시스템의 낮은 수요 및 높은 수요 모드를 모두 다룹니다. SIL 1, 2 또는 3의 능력으로 갖춰져 있습니다. 가스 탐지 기기 및 가스 탐지 시스템은 일반 제품으로 개발됩니다. 이 표준은 EN 61508-1:2010의 그림 2에서 정의된 전체 안전 생애주기의 10단계 "실현"의 일부를 다룹니다. 특정 응용 프로그램의 구성 및 통합은 이 표준에서 다루지 않습니다. 이 표준과 EN 61508의 요구 사항이 충돌할 경우 EN 50402가 우선합니다. 참고 1: 가스 탐지 시스템의 SIL 능력이 4인 응용 프로그램은 실현 가능하지 않습니다. 참고 2: 본 유럽 표준은 주로 고정 기기에 대해 적용됩니다. SIL이 1보다 높은 이동식 가스 탐지기의 경우에도 이 유럽 표준을 적용할 수 있습니다. 이 유럽 표준은 가연성 가스 및 증기(예: EN 60079-29-1 또는 EN 60079-29-4), 독성 가스(예: EN 45544) 또는 산소(예: EN 50104)의 전기 기기에 대한 유럽 표준의 요구 사항을 보완합니다. 참고 3: 이 유럽 표준을 "계량 표준"이라고 합니다. 위의 예는 이 유럽 표준을 발표시점의 산업 응용 분야의 표준화 상태를 보여줍니다. 이 외에도 본 유럽 표준이 적용 가능한 다른 응용 분야를 다루는 다른 계량 표준이 있을 수 있습니다. EN 50271은 소프트웨어 및/또는 디지털 구성 요소를 사용하는 기기에 대한 최소 요구 사항을 규정합니다. 또한 낮은 수요 모드 작동에서 SIL 1을 준수하기 위한 추가 선택 요구 사항을 정의합니다. EN 50402에는 EN 50271의 모든 요구 사항이 포함됩니다. EN 50402는 기기 및 가스 탐지 시스템 및/또는 구성 요소에 전용되며 다음의 경우에 EN 50271 대신 사용되어야합니다: - EN 50271에 포함되지 않은 구성 요소를 포함하는 시스템에서 SIL 1일 때; - SIL 2 및 SIL 3일 때; - 비디지털 기반 기기를 사용할 때 모든 SIL에서. 위에서 언급한 계량 표준을 적용하면 가스 탐지 시스템의 정상 운영에서 적절한 측정 성능을 보장합니다. 본 유럽 표준의 요구 사항은 가스 탐지 시스템의 기능적 안전을 다루며 신뢰성, 결함 허용성 및 체계적인 오류 회피를 기준으로 합니다. 체계적인 오류의 회피 및 제어는 설계에 선택된 개발 프로세스 및 기술 및 진단 조치 요구 사항에 의해 다루어집니다. 본 유럽 표준은 SIL 능력 및 관련 하드웨어 오류율을 통해 가스 탐지 시스템을 특성화하며 EN 61508의 안전 무결성 수준에 따라 전체 안전 시스템에 통합할 수 있습니다. 본 유럽 표준은 다음과 같은 기능적 유닛으로 구성된 가스 탐지 시스템에 적용됩니다: - 가스 샘플링; - 센서; - 신호 전송; - 제어 장치로의 입력; - 제어 장치에서의 신호 처리; - 제어 장치로부터의 출력. 이 유럽 표준은 가스 탐지 시스템의 설치 및 유지 관리 요구 사항을 규정하지 않습니다. 또한 측정 포인트/위치의 물리적 배치를 명시하지 않습니다. 이 유럽 표준은 어떤 SIL 능력이 특정 응용 프로그램에 충분한지를 규정하지 않습니다. 참고 4: 응용 프로그램의 SIL 능력 요구 사항은 사용자에 의해 지정됩니다(9절 및 부록 A 참조).
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