SIST EN 60079-29-2:2015

Explosive atmospheres - Part 29-2: Gas detectors - Selection, installation, use and maintenance of detectors for flammable gases and oxygen (IEC 60079-29-2:2015)

NEW! IEC 60079-29-2:2015 is available as IEC Standards+ 60079-29-2:2015 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60079-29-2:2015 gives guidance on, and recommended practice for, the selection, installation, safe use and maintenance of electrically operated Group II equipment intended for use in industrial and commercial safety applications and Group I equipment in underground coal mines for the detection and measurement of flammable gases complying with the requirements of IEC 60079-29-1  or IEC 60079-29-4. This second edition cancels and replaces the first edition published in 2007. This edition constitutes a technical revision. Please refer to the Foreword of the document for a listing of the changes from the previous edition.
Keywords: gas detectors, flammable gases, vapours

Explosionsfähige Atmosphäre - Teil 29-2: Gasmessgeräte - Auswahl, Installation, Einsatz und Wartung von Geräten für die Messung von brennbaren Gasen und Sauerstoff (IEC 60079-29-2:2015)

Atmosphères explosives - Partie 29-2: Détecteurs de gaz - Sélection, installation, utilisation et maintenance des détecteurs de gaz inflammables et d'oxygène (IEC 60079-29-2:2015)

IEC 60079-29-2:2015 donne des lignes directrices et des recommandations pratiques pour la sélection, l’installation, l’utilisation en toute sécurité et la maintenance des matériels électriques de groupe II destinés à une utilisation dans des applications de sécurité sur des sites industriels et commerciaux, et des matériels de groupe I utilisés dans les mines de charbon souterraines pour la détection et le mesurage des gaz inflammables conformément aux exigences de l'IEC 60079-29-1 ou de l'IEC 60079-29-4.
La présente version bilingue (2017-12) correspond à la version anglaise monolingue publiée en 2015-03.
Cette deuxième édition annule et remplace la première édition parue en 2007. Cette édition constitue une révision technique.
Cette édition inclut les modifications majeures suivantes par rapport à l'édition précédente:
1) Ajout du Groupe 1 au Domaine d’application
2) Ajout de la Détection de gaz à chemin ouvert
3) Ajout d’applications spécifiques
4) Améliorations apportées aux systèmes d’échantillonnage
Mots-clés: détecteurs de gaz, gaz inflammables, vapeurs

Eksplozivne atmosfere - 29-2. del: Javljalniki plina - Izbira, vgradnja, uporaba in vzdrževanje detektorjev za gorljive pline in kisik (IEC 60079-29-2:2015)

Ta del standarda IEC 60079-29 podaja smernice in priporočeno prakso za izbiro, namestitev, varno uporabo in vzdrževanje električno upravljane opreme skupine II, namenjene varnostni uporabi v industrijske in komercialne namene, in opreme skupine I v podzemnih premogovnikih za zaznavanje in merjenje gorljivih plinov, ki ustreza zahtevam standarda IEC 60079-29-1 ali IEC 60079-29-4.
Ta standard se uporablja za merjenje kisika za namene inertizacije v okoljih, kjer se zaščita pred eksplozijami zagotavlja z izključevanjem kisika namesto z merjenjem prisotnih gorljivih plinov ali hlapov. Uporablja se tudi za merjenje kisika pri inertizaciji izčrpanih območij v podzemnem premogovniku.
Ta standard je zbirka praktičnega znanja za pomoč uporabniku in se uporablja za opremo, instrumente in sisteme, ki kažejo na prisotnost gorljive ali potencialno eksplozivne mešanice plina ali hlapov z zrakom z uporabo električnega signala iz senzorjev plina, ki izvede meritve za odbiranje, aktivira vidni ali zvočni prednastavljeni alarm ali drugo napravo ali izvede kombinacijo obojega.
Taka oprema se lahko uporablja za zmanjševanje tveganja, kjer obstaja možnost, da je ogroženo človeško življenje ali lastnina predvsem zaradi nabiranja gorljive mešanice zraka in plina, in sicer tako, da opozarja na možno nevarnost. Uporablja se lahko tudi za sprožanje določenih varnostnih preventivnih ukrepov (npr. zaustavitev obrata, evakuacijo, sprožanje gasilnih postopkov).
Ta standard se uporablja za fiksne naprave in prevozno opremo. Uporablja se tudi za varno rabo prenosne opreme. Ker veliko moderne opreme te vrste vključuje tudi zaznavanje pomanjkanja kisika in/ali določene detektorje strupenega plina, so podane tudi dodatne smernice, ki pokrivajo te teme. Za potrebe tega standarda, razen kjer je izrecno drugače določeno, gorljivi
plini vključujejo tudi gorljive hlape. Ta standard ne zajema meglic zaradi trenutno uporabljeni tehnik merjenja,
Ta standard velja za opremo skupine II (tj. oprema, namenjena varnostni uporabi v industrijske in komercialne namene na območjih, ki so razvrščena v skladu s standardom IEC 60079-10-1) in opremo skupine I.
Za potrebe tega standarda oprema vključuje
a) fiksno opremo vključno z opremo, nameščeno na vozila;
b) prevozno opremo in
c) portable equipment.
Ta standard ne pokriva, vendar lahko nudi koristne informacije v zvezi z:
a) opremo, namenjeno izključno zaznavanju negorljivih strupenih plinov;
b) laboratorijsko ali znanstveno opremo, namenjeno izključno analizi ali merjenju;
c) opremo, namenjeno izključno nadzoru procesov;
d) opremo, namenjeno obdelavi in izdelavi eksplozivov;
e) opremo, namenjeno zaznavanju eksplozivne atmosfere, ki je posledica prahu ali meglic v zraku.

General Information

• Status: Published
• Publication Date: 28-Jul-2015
• ICS: 13.320 - Alarm and warning systems
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: EXP - Product for explosive atmospheres
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 22-May-2015
• Due Date: 27-Jul-2015
• Completion Date: 29-Jul-2015
• 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
• Ref Project: EN 60079-29-2:2015 - Explosive atmospheres - Part 29-2: Gas detectors - Selection, installation, use and maintenance of detectors for flammable gases and oxygen

Relations

• Replaces: SIST EN 60079-29-2:2008 - Explosive atmospheres -- Part 29-2: Gas detectors - Selection, installation, use and maintenance of detectors for flammable gases and oxygen
• Effective Date: 07-Jun-2022
• Revised: SIST EN 60079-29-2:2008 - Explosive atmospheres -- Part 29-2: Gas detectors - Selection, installation, use and maintenance of detectors for flammable gases and oxygen
• Effective Date: 12-Apr-2013

Overview

SIST EN 60079-29-2:2015 (IEC 60079-29-2:2015) provides guidance and recommended practices for the selection, installation, use and maintenance of gas detectors used to detect flammable gases, vapours and oxygen in explosive atmospheres. It applies to electrically operated Group II equipment for industrial and commercial safety applications and to Group I equipment used in underground coal mines. This second edition replaces the 2007 edition and is a technical revision adopted as a European standard (EN 60079-29-2:2015).

Key topics and technical content

The standard covers practical and technical subjects essential to reliable gas detector systems:

• Terms and definitions for gas properties, sensors, signals and alarms, and timing/behaviour parameters.
• Basic information on gases and vapours, including properties, behaviour, differences between gases and vapours, and oxygen deficiency hazards.
• Measuring principles and sensor technologies, with guidance on:
  • Catalytic sensors
  • Thermal conductivity sensors
  • Infrared (IR) sensors
  • Semiconductor sensors
  • Electrochemical sensors
  • Flame ionisation detectors (FID), flame temperature analysers (FTA) and photoionisation detectors (PID)
  • Paramagnetic oxygen detectors
  • Considerations for open-path detectors
• Selection criteria for fixed, transportable and portable equipment, including gas ranges, cross-sensitivities, electromagnetic immunity and intended Zone(s) of use.
• Installation, use and maintenance best practices to ensure reliable performance and alarm integrity.
• Behaviour of gas releases, risk reduction strategies (e.g., explosion prevention, gas-free work permits) and monitoring approaches (e.g., air inlet surveillance).
• Normative references and links to performance standards IEC 60079-29-1 and IEC 60079-29-4 for detector performance requirements.

Practical applications & users

This standard is essential for professionals responsible for safety in environments where flammable gases and oxygen hazards exist:

• Safety and instrumentation engineers specifying gas detection systems for petrochemical plants, refineries, chemical plants, LNG terminals, and storage facilities
• Maintenance teams and calibration technicians implementing detector maintenance and testing regimes
• Facilities and operations managers establishing gas monitoring programs, confined-space entry and gas-free permit procedures
• Mine operators using gas detection equipment in underground coal mines
• Manufacturers and integrators of gas detectors ensuring compatibility with IEC performance standards
• Certification bodies and compliance officers evaluating installations to meet explosion-atmosphere regulations

Related standards

Normative references include, among others:

• IEC 60079-0 (general requirements)
• IEC 60079-29-1 (performance requirements for flammable gas detectors)
• IEC 60079-29-4 (open-path detector performance)
• IEC 60079-10-1, IEC 60079-14, IEC 60079-17, IEC 60079-19, IEC 60079-20-1, IEC 61326-1

This standard is a practical resource for improving gas detection reliability, reducing explosion risk and ensuring compliance when monitoring flammable gases and vapours in hazardous areas.

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2015
Eksplozivne atmosfere - 29-2. del: Javljalniki plina - Izbira, vgradnja, uporaba in
vzdrževanje detektorjev za gorljive pline in kisik (IEC 60079-29-2:2015)
Explosive atmospheres - Part 29-2: Gas detectors - Selection, installation, use and
maintenance of detectors for flammable gases and oxygen (IEC 60079-29-2:2015)
Explosionsfähige Atmosphäre - Teil 29-2: Gasmessgeräte - Auswahl, Installation,
Einsatz und Wartung von Geräten für die Messung von brennbaren Gasen und
Sauerstoff (IEC 60079-29-2:2015)
$WPRVSKqUHVH[SORVLYHV3DUWLH'pWHFWHXUVGHJD]6pOHFWLRQLQVWDOODWLRQ
XWLOLVDWLRQHWPDLQWHQDQFHGHVGpWHFWHXUVGHJD]LQIODPPDEOHVHWG
R[\JqQH
,(&
Ta slovenski standard je istoveten z: EN 60079-29-2:2015
ICS:
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 60079-29-2

NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2015
ICS 29.260.20 Supersedes EN 60079-29-2:2007
English Version
Explosive atmospheres - Part 29-2: Gas detectors - Selection,
installation, use and maintenance of detectors for flammable
gases and oxygen
(IEC 60079-29-2:2015)
Atmosphères explosives - Partie 29-2: Détecteurs de gaz - Explosionsfähige Atmosphäre - Teil 29-2: Gasmessgeräte -
Sélection, installation, utilisation et maintenance des Auswahl, Installation, Einsatz und Wartung von Geräten für
détecteurs de gaz inflammables et d'oxygène die Messung von brennbaren Gasen und Sauerstoff
(IEC 60079-29-2:2015) (IEC 60079-29-2:2015)
This European Standard was approved by CENELEC on 2015-04-20. 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, 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
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60079-29-2:2015 E
Foreword
The text of document 31/1169/FDIS, future edition 2 of IEC 60079-29-2, prepared by IEC TC 31,
Equipment for explosive atmospheres, was submitted to the IEC-CENELEC parallel vote and approved
by CENELEC as EN 60079-29-2:2015.

The following dates are fixed:

(dop) 2016-01-20
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2018-04-20
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60079-29-2:2007.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
Endorsement notice
The text of the International Standard IEC 60079-29-2:2015 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60079-14 NOTE Harmonized as EN 60079-14.
IEC 60079-20-1 NOTE Harmonized as EN 60079-20-1.
IEC 61326-1 NOTE Harmonized as EN 61326-1.
IEC 60079-29-3 NOTE Harmonized as EN 60079-29-3.

- 3 - EN 60079-29-2:2015
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year

IEC 60079-0 -  Explosive atmospheres -- Part 0: Equipment EN 60079-0 -
- General requirements
- -  +A11 -
IEC 60079-10-1 2008 Explosive atmospheres -- Part 10-1: EN 60079-10-1 2009
Classification of areas - Explosive gas
atmospheres
IEC 60079-10-2 -  Explosive atmospheres -- Part 10-2: EN 60079-10-2 -
Classification of areas - Combustible dust
atmospheres
IEC 60079-13 -  Explosive atmospheres -- Part 13: EN 60079-13 -
Equipment protection by pressurized room
"p"
IEC 60079-17 -  Explosive atmospheres -- Part 17: Electrical EN 60079-17 -
installations inspection and maintenance
IEC 60079-19 -  Explosive atmospheres -- Part 19: EN 60079-19 -
Equipment repair, overhaul and reclamation
IEC 60079-29-1 2007 Explosive atmospheres -- Part 29-1: Gas EN 60079-29-1 2007
(mod) detectors - Performance requirements of
detectors for flammable gases
IEC 60079-29-4 -  Explosive atmospheres -- Part 29-4: Gas EN 60079-29-4 -
detectors - Performance requirements of
open path detectors for flammable gases
IEC 61285 -  Industrial-process control - Safety of EN 61285 -
analyzer houses
IEC 60079-29-2 ®
Edition 2.0 2015-03
INTERNATIONAL
STANDARD
Explosive atmospheres –
Part 29-2: Gas detectors – Selection, installation, use and maintenance of

detectors for flammable gases and oxygen

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-2342-0

– 2 – IEC 60079-29-2:2015  IEC 2015
CONTENTS
FOREWORD . 8
INTRODUCTION . 11
1 Scope . 13
2 Normative references . 14
3 Terms and definitions . 14
3.1 Gas properties and other physics . 14
3.2 Types of equipment . 16
3.3 Sensors and detectors . 18
3.4 Supply of gas to instruments . 19
3.5 Signals and alarms . 19
3.6 Times, checks and equipment behaviour . 20
3.7 Terms exclusive to open path equipment . 21
4 Basic information on the properties, behaviour, gases and vapours, and specific
applications of gas detection . 23
4.1 Detecting gases and vapours . 23
4.1.1 General . 23
4.1.2 Safety when monitoring for flammable gases where personnel could be
present . 24
4.2 Some common properties of gases and vapours . 25
4.3 The differences between detecting gases and vapours . 26
4.3.1 General . 26
4.3.2 Detection of gases . 26
4.3.3 Detection of vapours . 28
4.4 Oxygen deficiency. 31
4.4.1 General . 31
4.4.2 Chemical reaction of oxygen, with solid products . 31
4.4.3 Chemical reaction of oxygen, with gaseous products . 31
4.4.4 Dilution of the air by displacement by some other gas or vapour . 32
4.5 Specific applications of gas detection . 32
4.5.1 Gas detection as means of reducing risk of explosion . 32
4.5.2 Gas free work permit . 35
4.5.3 Monitoring of air inlets . 36
4.6 Specific considerations for open path detection . 36
5 Measuring principles . 37
5.1 General . 37
5.2 Catalytic sensors . 39
5.2.1 General . 39
5.2.2 Common applications . 39
5.2.3 Limitations . 39
5.2.4 Interferences . 40
5.2.5 Poisoning . 40
5.3 Thermal conductivity sensors . 41
5.3.1 General . 41
5.3.2 Common applications . 41
5.3.3 Limitations . 41
5.3.4 Interferences . 41

IEC 60079-29-2:2015  IEC 2015 – 3 –
5.3.5 Poisoning . 41
5.4 Infrared sensors . 41
5.4.1 General . 41
5.4.2 Common applications . 42
5.4.3 Limitations . 42
5.4.4 Interferences . 42
5.4.5 Poisoning . 42
5.5 Semiconductor sensors . 43
5.5.1 General . 43
5.5.2 Common applications . 43
5.5.3 Limitations . 43
5.5.4 Interferences . 43
5.5.5 Poisoning . 43
5.6 Electrochemical sensors . 44
5.6.1 General . 44
5.6.2 Common applications . 44
5.6.3 Limitations . 44
5.6.4 Interferences . 44
5.6.5 Poisoning . 44
5.7 Flame ionization detectors (FID) . 45
5.7.1 General . 45
5.7.2 Common applications . 45
5.7.3 Limitations . 45
5.7.4 Interferences . 45
5.7.5 Poisoning . 45
5.8 Flame temperature analysers (FTA) . 45
5.8.1 General . 45
5.8.2 Common applications . 45
5.8.3 Limitations . 46
5.8.4 Interferences . 46
5.8.5 Poisoning . 46
5.9 Photo ionisation detector (PID) . 46
5.9.1 General . 46
5.9.2 Common applications . 46
5.9.3 Limitations . 46
5.9.4 Interferences . 46
5.9.5 Poisoning . 47
5.10 Paramagnetic oxygen detector . 47
5.10.1 General . 47
5.10.2 Common applications . 47
5.10.3 Limitations . 47
5.10.4 Interference . 47
5.10.5 Poisoning . 47
6 Selection of equipment . 47
6.1 General . 47
6.2 Selection criteria . 48
6.2.1 General criteria . 48
6.2.2 Gases to be detected by the equipment . 49
6.2.3 Application of fixed equipment . 50

– 4 – IEC 60079-29-2:2015  IEC 2015
6.2.4 Application of transportable and portable equipment . 54
6.3 Miscellaneous factors affecting selection of equipment . 55
6.3.1 Electromagnetic immunity . 55
6.3.2 Intended Zone(s) of use . 55
7 Behaviour of gas releases . 55
7.1 Nature of a release . 55
7.1.1 General . 55
7.1.2 Release rate of gas or vapour . 55
7.1.3 Flammable limits . 56
7.1.4 Ventilation . 56
7.1.5 Relative density of the released gas or vapour. 56
7.1.6 Temperature and/or pressure. 57
7.1.7 Other parameters to be considered . 57
7.1.8 Outdoor sites and open structures . 57
7.2 Buildings and enclosures . 57
7.2.1 General . 57
7.2.2 Unventilated buildings and enclosures . 57
7.2.3 Ventilated buildings and enclosures . 58
7.3 Environmental considerations . 59
8 Design and installation of fixed gas detection systems . 59
8.1 General . 59
8.2 Basic considerations for the installation of fixed systems . 59
8.2.1 General . 59
8.2.2 Point detection equipment and remote sensors . 60
8.2.3 Systems consisting of sampling equipment . 60
8.2.4 Open path (line of sight) equipment . 61
8.3 Location of detection points . 61
8.3.1 General . 61
8.3.2 General site considerations . 61
8.3.3 Environmental conditions . 62
8.4 Access for calibration and maintenance . 65
8.5 Additional considerations for sample lines . 65
8.6 Additional considerations for open path equipment . 66
8.7 Summary of considerations for the location of measuring points and open
paths . 66
8.8 Installation of measuring point and open path equipment . 67
8.9 Integrity and safety of fixed systems . 67
8.9.1 General . 67
8.9.2 Redundancy in fixed systems. 68
8.9.3 Protection against loss of main power supply . 68
8.10 Timing of installation during construction operations . 68
8.11 Commissioning . 68
8.11.1 Inspection . 68
8.11.2 Initial gas calibration . 69
8.11.3 Adjustment of alarm set points . 69
8.12 Operating instructions, plans and records . 70
9 Use of portable and transportable flammable gas detection equipment . 70
9.1 General . 70

IEC 60079-29-2:2015  IEC 2015 – 5 –
9.2 Initial and periodic check procedures for portable and transportable
instrumentation . 71
9.2.1 General . 71
9.2.2 Inspection and functional checks . 72
9.2.3 Routine tests and recalibration . 73
9.2.4 Maintenance and recalibration . 73
9.3 Guidance on the use of portable and transportable equipment . 74
9.3.1 Electrical safety in hazardous atmospheres . 74
9.3.2 Safety of personnel . 74
9.3.3 Spot tests and sampling . 75
9.3.4 Sampling above liquids . 75
9.3.5 Avoidance of condensation . 75
9.3.6 Poisoning of sensors . 75
9.3.7 Changes of temperature . 76
9.3.8 Accidental damage . 76
9.3.9 Minimalist operation, the “Read and run” concept . 76
10 Training of operational personnel . 76
10.1 General . 76
10.2 General training – Basic limitations and safety . 77
10.3 Operator training . 77
10.4 Maintenance training . 78
11 Maintenance, routine procedures and general administrative control . 78
11.1 General . 78
11.2 Operational checks . 80
11.2.1 General . 80
11.2.2 Fixed systems . 80
11.2.3 Portable and transportable gas detection equipment . 81
11.3 Maintenance . 81
11.3.1 General . 81
11.3.2 Fixed equipment . 81
11.3.3 Portable and transportable gas detection equipment . 82
11.3.4 Off-site maintenance, general . 82
11.3.5 Maintenance procedures. 82
11.4 Sensors . 82
11.4.1 General . 82
11.4.2 Flame arrestor . 83
11.5 Flow systems . 83
11.5.1 General . 83
11.5.2 Inspection . 83
11.5.3 Filters, traps and flame arrestors . 83
11.5.4 Flow system and sample chamber . 83
11.5.5 Flow connections . 83
11.5.6 Moving parts . 83
11.5.7 Automatic sample-draw systems . 83
11.5.8 Loss-of-flow signals . 83
11.6 Readout devices . 83
11.6.1 General . 83
11.6.2 Other readouts . 84
11.7 Alarms . 84

– 6 – IEC 60079-29-2:2015  IEC 2015
11.8 Calibration . 84
11.8.1 Calibration kits and test equipment . 84
11.8.2 Calibration procedure . 85
Annex A (normative) Measuring principles . 87
A.1 General . 87
A.2 Catalytic sensors . 89
A.2.1 General . 89
A.2.2 Common applications . 90
A.2.3 Limitations . 90
A.2.4 Interferences . 90
A.2.5 Poisoning . 91
A.3 Thermal conductivity sensors . 92
A.3.1 General . 92
A.3.2 Common applications . 92
A.3.3 Limitations . 93
A.3.4 Interferences . 93
A.3.5 Poisoning . 93
A.4 Infrared sensors . 93
A.4.1 General . 93
A.4.2 Common applications . 95
A.4.3 Limitations . 96
A.4.4 Interferences . 96
A.4.5 Poisoning . 97
A.5 Semi-conductor sensors. 97
A.5.1 General . 97
A.5.2 Common applications . 97
A.5.3 Limitations . 97
A.5.4 Interferences . 98
A.5.5 Poisoning . 98
A.6 Electrochemical sensors . 98
A.6.1 General . 98
A.6.2 Common applications . 99
A.6.3 Limitations . 99
A.6.4 Interferences . 100
A.6.5 Poisoning . 100
A.7 Flame ionization detectors (FID) . 101
A.7.1 General . 101
A.7.2 Common applications . 102
A.7.3 Limitations . 102
A.7.4 Interferences . 102
A.7.5 Poisoning . 102
A.8 Flame temperature analysers (FTA) . 103
A.8.1 General . 103
A.8.2 Common applications . 103
A.8.3 Limitations . 103
A.8.4 Interferences . 103
A.8.5 Poisoning . 103
A.9 Photo ionisation detector (PID) . 104
A.9.1 General . 104

IEC 60079-29-2:2015  IEC 2015 – 7 –
A.9.2 Common applications . 104
A.9.3 Limitations . 105
A.9.4 Interferences . 105
A.9.5 Poisoning . 105
A.10 Paramagnetic oxygen detector . 105
A.10.1 General . 105
A.10.2 Common applications . 106
A.10.3 Limitations . 106
A.10.4 Interference . 106
A.10.5 Poisoning . 106
Annex B (informative) Environmental parameters . 107
Annex C (informative) Typical environmental and application check-list for flammable
gas detectors (for both Group I and Group II equipment) . 108
Annex D (informative) Typical instrument maintenance record for flammable gas
detectors . 110
Annex E (informative) Atmospheric visibility . 112
Bibliography . 113

Figure 1 – Integral concentration over the path length. 37
Figure 2 – Average concentration over the path length . 37

Table 1 – Typical Tasks and Most Relevant Causes . 12
Table 2 – Overview of gas detection equipment with different measuring principles . 38
Table A.1 – Overview of gas detection equipment with different measuring principles . 88
Table B.1 – Environmental parameters . 107

– 8 – IEC 60079-29-2:2015  IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 29-2: Gas detectors – Selection, installation, use
and maintenance of detectors for flammable gases and oxygen

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
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agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60079-29-2 has been prepared by IEC technical committee 31:
Equipment for explosive atmospheres.
This second edition cancels and replaces the first edition published in 2007. This edition
constitutes a technical revision.

IEC 60079-29-2:2015  IEC 2015 – 9 –
This edition includes the following significant changes with respect to the previous edition:
Type
Changes Clause Minor and Extension Major technical
editorial changes
changes
Addition of group 1 to scope 1 x
Addition of Open Path Gas Detection 3, 4.6, 5.4, x
6.2.3.5, 8.2,
8.6, 8.7. 8.8,
11, A4
Changed “combustible” to “flammable” Throughout x
Addition of specific applications 4.5 x
Improvements to sampling systems 6.2.3.4, 8.2.3, x
8.5, 11.2.2
NOTE The technical changes referred to include the significance of technical changes in the revised IEC
Standard, but they do not form an exhaustive list of all modifications from the previous version. More guidance may
be found by referring to the Redline Version of the standard.
Explanations:
1) Minor and editorial changes clarification
decrease of technical requirements
minor technical change
editorial corrections
These are changes which modify requirements in an editorial or a minor technical way.
They include changes of the wording to clarify technical requirements without any
technical change, or a reduction in level of existing requirement.
2) Extension addition of technical options
These are changes which add new or modify existing technical requirements, in a way that
new options are given, but without increasing requirements for equipment that was fully
compliant with the previous standard. Therefore, these will not have to be considered for
products in conformity with the preceding
...