International Standards and Conformity Assessment for all electrical, electronic and related technologies



Reference EN 50402:2005
Title Electrical apparatus for the detection and measurement of combustible or toxic gases or vapours or of oxygen - Requirements on the functional safety of fixed gas detection systems
Project Number 14046
Abstract/Scope This European Standard is applicable to fixed gas detection systems for the detection and measurement of flammable or toxic gases or vapours or oxygen. 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 61779 or EN 50241), toxic gases (e.g. EN 45544) or oxygen (e.g. EN 50104). NOTE 1 These European Standards will be mentioned in the text as "metrological standards". NOTE 2 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 standard is also applicable. NOTE 3 For fixed apparatus used for safety applications with a SIL requirement up to 1 and for portable apparatus the European Standard EN 50271 may be applied instead of this European Standard. 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 faults. 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 or the categories of EN ISO 13849-1 (see Annex B). This European Standard is a product standard which is based on EN 61508 and includes additional requirements of EN ISO 13849-1. It covers part of the phase 9 “realisation” of the overall safety lifecycle defined in EN 61508-1. 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 sensors.. 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 Annexes A and B).


Current Stage code 6060
Current Stage code date 2005-08-19
Current Stage code deadline 2006-07-01
Deadline date for vote  


Order Voucher  


IEC Technical Body IEC/TC 31
Reference Document  
ICS 13.320 - Alarm and warning systems
Keywords Gas detection; Combustible; Toxic; Vapour; Oxygen
Note Corrigendum to EN (French version only) issued January 2009
Special National Condition(s)  


Categories - Aspects
Product Life Cycle


Deadline Date
6060 2005-08-19 2006-07-01 export to doc file  EN  FR  DE
5099 2005-07-01 2006-01-01  
5020 2005-03-11 2005-06-10  
4099 2003-11-14 2005-01-01  
4060 2003-06-24 2003-12-02  
4020 2002-12-20 2003-06-20  
3099 2002-09-12 2002-12-01  
3020 2000-07-06 2001-01-06  

Implementation Dates

date of Ratification (DOR) (1) 2005-07-01
date of Availability (DAV) (2) 2005-08-19
date of Announcement (DOA) (3) 2006-01-01
date of Publication (DOP) (4) 2006-07-01
date of Withdrawal (DOW) (5) 2008-07-01


Superseded by prEN 50402:2013
Normative reference (6)  

(1) Date of ratification (dor) date when the Technical Board notes the approval of an EN (and HD for CENELEC), from which time the standard may be said to be approved

(2) Date of availability (dav) date when the definitive text in the official language versions of an approved CEN/CENELEC publication is distributed by the Central Secretariat

(3) Date of announcement (doa) latest date by which the existence of an EN (and HD for CENELEC), a TS or a CWA has to be announced at national level

(4) Date of publication (dop) latest date by which an EN has to be implemented at national level by publication of an identical national standard or by endorsement

(5) Date of withdrawal (dow) latest date by which national standards conflicting with an EN (and HD for CENELEC) have to be withdrawn

(6) This list of normative references is purely indicative. The only official list of normative reference is the list of the published standard.