Workplace atmospheres - Part 2: Gas detectors - Selection, installation, use and maintenance of detectors for toxic gases and vapours (IEC 62990-2:2021)

This document gives guidance on the selection, installation, use and maintenance of electrical
equipment used for the measurement of toxic gases and vapours in workplace atmospheres.
The primary purpose of such equipment is to ensure safety of personnel and property by
providing an indication of the concentration of a toxic gas or vapour and warning of its presence.
This document is applicable to equipment whose purpose is to provide an indication, alarm or
other output function to give a warning of the presence of a toxic gas or vapour in the
atmosphere and in some cases to initiate automatic or manual protective actions. It is applicable
to equipment in which the sensor automatically generates an electrical signal when gas is
present.
For the purposes of this document, equipment includes:
a) fixed equipment;
b) transportable equipment, and
c) portable equipment.
This document is intended to cover equipment defined within IEC 62990-1, but can provide
useful information for equipment not covered by that document.

Arbeitsplatzatmosphäre - Teil 2: Gasmessgeräte - Auswahl, Installation, Einsatz und Wartung von Gasmessgeräten für toxische Gase und Dämpfe (IEC 62990-2:2021)

Atmosphères des lieux de travail - Partie 2 : Détecteurs de gaz - Sélection, installation, utilisation et maintenance des détecteurs de gaz et de vapeurs toxiques (IEC 62990-2:2021)

Zrak na delovnem mestu - 2. del: Plinski detektorji - Izbira, vgraditev, uporaba in vzdrževanje detektorjev strupenih plinov in hlapov (IEC 62990-2:2021)

General Information

Status
Published
Public Enquiry End Date
19-May-2019
Publication Date
08-Nov-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
09-Aug-2021
Due Date
14-Oct-2021
Completion Date
09-Nov-2021

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SLOVENSKI STANDARD
SIST EN IEC 62990-2:2021
01-december-2021

Zrak na delovnem mestu - 2. del: Plinski detektorji - Izbira, vgraditev, uporaba in

vzdrževanje detektorjev strupenih plinov in hlapov (IEC 62990-2:2021)
Workplace atmospheres - Part 2: Gas detectors - Selection, installation, use and
maintenance of detectors for toxic gases and vapours (IEC 62990-2:2021)

Arbeitsplatzatmosphäre - Teil 2: Gasmessgeräte - Auswahl, Installation, Einsatz und

Wartung von Gasmessgeräten für toxische Gase und Dämpfe (IEC 62990-2:2021)

Atmosphères des lieux de travail - Partie 2 : Détecteurs de gaz - Sélection, installation,

utilisation et maintenance des détecteurs de gaz et de vapeurs toxiques (IEC 62990-

2:2021)
Ta slovenski standard je istoveten z: EN IEC 62990-2:2021
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
13.320 Alarmni in opozorilni sistemi Alarm and warning systems
SIST EN IEC 62990-2:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN IEC 62990-2:2021
---------------------- Page: 2 ----------------------
SIST EN IEC 62990-2:2021
EUROPEAN STANDARD EN IEC 62990-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2021
ICS 29.260.20
English Version
Workplace atmospheres - Part 2: Gas detectors - Selection,
installation, use and maintenance of detectors for toxic gases
and vapours
(IEC 62990-2:2021)

Atmosphères des lieux de travail - Partie 2 : Détecteurs de Arbeitsplatzatmosphäre - Teil 2: Gasmessgeräte - Auswahl,

gaz - Sélection, installation, utilisation et maintenance des Installation, Einsatz und Wartung von Gasmessgeräten für

détecteurs de gaz et de vapeurs toxiques toxische Gase und Dämpfe
(IEC 62990-2:2021) (IEC 62990-2:2021)

This European Standard was approved by CENELEC on 2021-07-09. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, 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: Rue de la Science 23, B-1040 Brussels

© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 62990-2:2021 E
---------------------- Page: 3 ----------------------
SIST EN IEC 62990-2:2021
EN IEC 62990-2:2021 (E)
European foreword

The text of document 31/1566/FDIS, future edition 1 of IEC 62990-2, prepared by IEC/TC 31

“Equipment for explosive atmospheres” was submitted to the IEC-CENELEC parallel vote and

approved by CENELEC as EN IEC 62990-2:2021.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2022–04–09

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2024–07–09

document have to be withdrawn

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.

Any feedback and questions on this document should be directed to the users’ national committee. A

complete listing of these bodies can be found on the CENELEC website.
Endorsement notice

The text of the International Standard IEC 62990-2:2021 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 60079-10-1 NOTE Harmonized as EN IEC 60079-10-1
IEC 60079-0 NOTE Harmonized as EN IEC 60079-0
---------------------- Page: 4 ----------------------
SIST EN IEC 62990-2:2021
EN IEC 62990-2:2021 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments)

applies.

NOTE 1 Where 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 60079-29-2 - Explosive atmospheres - Part 29–2: Gas EN 60079-29-2 -
detectors - Selection, installation, use and
maintenance of detectors for flammable
gases and oxygen
IEC 62990-1 - Workplace atmospheres - Part 1: Gas - -
detectors - Performance requirements of
detectors for toxic gases
---------------------- Page: 5 ----------------------
SIST EN IEC 62990-2:2021
---------------------- Page: 6 ----------------------
SIST EN IEC 62990-2:2021
IEC 62990-2
Edition 1.0 2021-06
INTERNATIONAL
STANDARD
colour
inside
Workplace atmospheres –

Part 2: Gas detectors – Selection, installation, use and maintenance of detectors

for toxic gases and vapours
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.260.20 ISBN 978-2-8322-9746-9

Warning! Make sure that you obtained this publication from an authorized distributor.

---------------------- Page: 7 ----------------------
SIST EN IEC 62990-2:2021
– 2 – IEC 62990-2:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Properties and detection of toxic gases and vapours ..................................................... 13

4.1 Properties and detection ....................................................................................... 13

4.2 The difference between detecting gases and vapours ........................................... 14

4.3 Effects of water vapour on detection ..................................................................... 17

4.4 Effects of temperature and pressure on detection ................................................. 17

4.5 Effects of corrosion on detection ........................................................................... 17

4.6 Detection by oxygen deficiency measurement ....................................................... 17

5 Measurement tasks ....................................................................................................... 18

5.1 General ................................................................................................................. 18

5.2 Exposure measurement (health monitoring) .......................................................... 18

5.3 General gas detection (safety monitoring) ............................................................. 19

6 Selection of equipment .................................................................................................. 20

6.1 General ................................................................................................................. 20

6.2 Performance and electrical tests ........................................................................... 21

6.3 Indication range, measuring range and uncertainty of measurement ..................... 21

6.4 Selectivity requirements ........................................................................................ 22

6.5 The influence of environmental conditions ............................................................ 23

6.6 The influence of electromagnetic interference ....................................................... 23

6.7 Time of response and time of recovery ................................................................. 24

6.8 Time to alarm ........................................................................................................ 25

6.9 Data logging ......................................................................................................... 25

6.10 Instruction manual ................................................................................................ 26

7 Design and installation of fixed toxic gas detection equipment ....................................... 26

7.1 General ................................................................................................................. 26

7.2 Basic considerations for the installation of fixed systems ...................................... 27

7.3 Location of detection points .................................................................................. 28

7.4 Access for calibration and maintenance ................................................................ 33

7.5 Additional considerations for sample lines ............................................................. 33

7.6 Summary of considerations for the location of sensors or sampling points ............ 34

7.7 Installation of sensors ........................................................................................... 35

7.8 Integrity and safety of fixed systems ..................................................................... 35

7.9 Commissioning ..................................................................................................... 36

7.10 Operating instructions, plans and records ............................................................. 37

8 Operation of toxic gas detection equipment ................................................................... 38

8.1 Alarm setting......................................................................................................... 38

8.2 Operation of portable equipment ........................................................................... 39

8.3 Operation of transportable and fixed equipment .................................................... 43

8.4 Sample lines and sampling probes ........................................................................ 45

8.5 Accessories .......................................................................................................... 45

9 Maintenance and calibration .......................................................................................... 46

9.1 General ................................................................................................................. 46

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SIST EN IEC 62990-2:2021
IEC 62990-2:2021 © IEC 2021 – 3 –

9.2 Sensor .................................................................................................................. 46

9.3 Flow systems of aspirated equipment.................................................................... 46

9.4 Readout devices ................................................................................................... 47

9.5 Alarms .................................................................................................................. 47

9.6 Maintenance ......................................................................................................... 47

9.7 Calibration ............................................................................................................ 48

9.8 Operation test ....................................................................................................... 49

9.9 Records ................................................................................................................ 50

10 Training ......................................................................................................................... 50

10.1 General ................................................................................................................. 50

10.2 Operator training ................................................................................................... 50

10.3 Maintenance and calibration training ..................................................................... 51

Annex A (informative) Commonly used measurement principles ........................................... 52

A.1 General ................................................................................................................. 52

A.2 Chemiluminescence .............................................................................................. 52

A.3 Colorimetry ........................................................................................................... 53

A.4 Electrochemical .................................................................................................... 54

A.5 Flame-ionization ................................................................................................... 55

A.6 Gas chromatography ............................................................................................. 55

A.7 Infrared photometry .............................................................................................. 56

A.8 Ion mobility spectrometry ...................................................................................... 57

A.9 Mass spectrometry ................................................................................................ 58

A.10 Photo-ionization .................................................................................................... 59

A.11 Semiconductor ...................................................................................................... 60

A.12 Ultra-violet/visible photometry ............................................................................... 61

Bibliography .......................................................................................................................... 62

Figure 1 – Relationship between indication range and measuring range (See 6.3.1) ............. 11

Figure 2 – Example of zero uncertainty ................................................................................. 11

Figure 3 – Example of warm-up time in clean air ................................................................... 12

Figure 4 – Relationship between indication range and measuring range ............................... 22

Figure 5 – Gas response curves for test gas volume fractions of 40 ppm and 100 ppm ......... 24

Figure 6 – Time to alarm at 25 ppm set point for test gas volume fractions of 40 ppm

and 100 ppm ......................................................................................................................... 25

Table A.1 – Chemiluminescence ........................................................................................... 52

Table A.2 – Colorimetry ........................................................................................................ 53

Table A.3 – Electrochemical ................................................................................................. 54

Table A.4 – Flame-ionization ................................................................................................ 55

Table A.5 – Infrared photometry ............................................................................................ 56

Table A.6 – Ion mobility spectrometry ................................................................................... 57

Table A.7 – Mass spectrometry ............................................................................................. 58

Table A.8 – Photo-ionization (PID) ........................................................................................ 59

Table A.9 – Semiconductor ................................................................................................... 60

Table A.10 – Ultra-violet/visible photometry .......................................................................... 61

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SIST EN IEC 62990-2:2021
– 4 – IEC 62990-2:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WORKPLACE ATMOSPHERES –
Part 2: Gas detectors –
Selection, installation, use and maintenance
of detectors for toxic gases and vapours
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, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with

may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by 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

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

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

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

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 62990-2 has been prepared IEC technical committee 31: Equipment

for explosive atmospheres and ISO technical committee 146: Air quality, sub-committee 2:

Workplace atmospheres.
It is published as a double logo standard.
The text of this International Standard is based on the following documents:
FDIS Report on voting
31/1566/FDIS 31/1568/RVD

Full information on the voting for the approval of this International Standard can be found in the

report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 10 ----------------------
SIST EN IEC 62990-2:2021
IEC 62990-2:2021 © IEC 2021 – 5 –

A list of all parts in the IEC 62990, published under the general title Workplace atmospheres,

can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it

contains colours which are considered to be useful for the correct understanding of its

contents. Users should therefore print this document using a colour printer.
---------------------- Page: 11 ----------------------
SIST EN IEC 62990-2:2021
– 6 – IEC 62990-2:2021 © IEC 2021
INTRODUCTION

Toxic gas detection equipment can be used whenever there is the possibility of a hazard to life

or adverse health effects caused by the accumulation of a toxic gas or vapour. Such equipment

can provide a means of reducing the exposure to the hazard by detecting the presence of a

toxic gas or vapour and issuing suitable audible or visual warnings. Gas detectors can also be

used to initiate precautionary steps (for example, plant shutdown and evacuation).

Performance requirements for gas detection equipment for workplace atmospheres are set out

in IEC 62990 series standards.

However performance capability alone cannot ensure that the use of such equipment will

properly safeguard life and health where toxic gases and vapours might be present. The level

of safety obtained depends heavily upon correct selection, installation, calibration and periodic

maintenance of the equipment, combined with knowledge of the limitations of the detection

technique required. This cannot be achieved without responsible informed management.

This document has been specifically written to cover all the functions necessary from selection

to ongoing maintenance for a successful gas detection operation.
---------------------- Page: 12 ----------------------
SIST EN IEC 62990-2:2021
IEC 62990-2:2021 © IEC 2021 – 7 –
WORKPLACE ATMOSPHERES –
Part 2: Gas detectors –
Selection, installation, use and maintenance
of detectors for toxic gases and vapours
1 Scope

This document gives guidance on the selection, installation, use and maintenance of electrical

equipment used for the measurement of toxic gases and vapours in workplace atmospheres.

The primary purpose of such equipment is to ensure safety of personnel and property by

providing an indication of the concentration of a toxic gas or vapour and warning of its presence.

This document is applicable to equipment whose purpose is to provide an indication, alarm or

other output function to give a warning of the presence of a toxic gas or vapour in the

atmosphere and in some cases to initiate automatic or manual protective actions. It is applicable

to equipment in which the sensor automatically generates an electrical signal when gas is

present.
For the purposes of this document, equipment includes:
a) fixed equipment;
b) transportable equipment, and
c) portable equipment.

This document is intended to cover equipment defined within IEC 62990-1, but can provide

useful information for equipment not covered by that document.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.

IEC 60079-29-2, Explosive atmospheres – Part 29-2: Gas detectors – Selection, installation,

use and maintenance of detectors for flammable gases and oxygen

IEC 62990-1, Workplace atmospheres – Part 1: Gas detectors – Performance requirements of

detectors for toxic gases
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 62990-1 and the

following apply.

NOTE 1 Certain definitions within IEC 62990-1 are repeated below for the convenience of the reader.

---------------------- Page: 13 ----------------------
SIST EN IEC 62990-2:2021
– 8 – IEC 62990-2:2021 © IEC 2021

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

NOTE 2 Additional definitions applicable to explosive atmospheres can be found in Chapter 426 of the International

Electrotechnical Vocabulary (IEC 60050-426).
3.1
toxic gas

gas or vapour that can be harmful to human health and/or the performance of persons due to

its physical or physico-chemical properties

Note 1 to entry: For the purpose of this document, the term “toxic gas” includes “toxic vapours”.

3.2
interfering gas

any gas other than the gas to be detected, including water vapour, which affects the indication

3.3
clean air

air that is free of gases or vapours to which the sensor is sensitive or which influence the

performance of the sensor
3.4
zero gas

gas recommended by the manufacturer, which is free of toxic gases and interfering and

contaminating substances, the purpose of which is calibration or adjustment of the equipment

zero
3.5
volume fraction

quotient of the volume of a specified component and the sum of the volumes of all components

of a gas mixture before mixing, all volumes referring to the pressure and the temperature of the

gas mixture

Note 1 to entry: The volume fraction and volume concentration take the same value if, at the same state conditions,

the sum of the component volumes before mixing and the volume of the mixture are equal. However, because the

mixing of two or more gases at the same state conditions is usually accompanied by a slight contraction or, less

frequently, a slight expansion, this is not generally the case.
3.6
occupational exposure limit value
OELV

limit of the time-weighted average of the concentration of a chemical agent in the air within the

breathing zone of a worker in relation to a specified reference period

Note 1 to entry: The term “limit value” is often used as a synonym for “occupational exposure limit value”, but the

term “occupational exposure limit value” is preferred because there is more than one limit value (e.g., biological limit

value and occupational exposure limit value).

Note 2 to entry: Occupational exposure limit values (OELVs) are often set for reference periods of 8 h, but can also

be set for shorter periods or concentration excursions.
[SOURCE: ISO 18158:2016, 2.1.5.4, modified (Note 2 to entry is shortened)]
3.7
exposure (by inhalation)

situation in which a chemical agent is present in air that is inhaled by a person

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SIST EN IEC 62990-2:2021
IEC 62990-2:2021 © IEC 2021 – 9 –
3.8
time weighted average concentration
TWA concentration
concentration of gas in air averaged over a reference period
3.9
fixed equipment

equipment fastened to a support, or otherwise secured in a specific location, when energized

3.10
transportable equipment

equipment not intended to be carried by a person during operation, nor intended for fixed

installation
3.11
portable equipment
equipment intended to be carried by a person during its operation

Note 1 to entry: Portable equipment is battery powered and includes, but is not limited to;

a) hand-held equipment, typically less than 1 kg, which requires use of only one hand to operate,

b) personal monitors, similar in size and mass to the hand-held equipment, that are continuously operating while

they are attached to the user, and,

c) larger equipment that can be operated by the user while it is carried either by hand, by a shoulder strap or

carrying harness and which might or might not have a ha
...

SLOVENSKI STANDARD
oSIST prEN IEC 62990-2:2019
01-maj-2019

Zrak na delovnem mestu - 2. del: Plinski detektorji - Izbira, vgraditev, uporaba in

vzdrževanje detektorjev strupenih plinov, hlapov in kisika
Workplace atmospheres - Part 2: Gas detectors - Selection, installation, use and
maintenance of detectors for toxic gases and vapours and oxygen
Ta slovenski standard je istoveten z: prEN IEC 62990-2:2019
ICS:
13.040.30 Kakovost zraka na delovnem Workplace atmospheres
mestu
13.320 Alarmni in opozorilni sistemi Alarm and warning systems
oSIST prEN IEC 62990-2:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN IEC 62990-2:2019
---------------------- Page: 2 ----------------------
oSIST prEN IEC 62990-2:2019
31/1445/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62990-2 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2019-03-01 2019-05-24
SUPERSEDES DOCUMENTS:
31/1364/CD,31/1374A/CC
IEC TC 31 : EQUIPMENT FOR EXPLOSIVE ATMOSPHERES
SECRETARIAT: SECRETARY:
United Kingdom Mr Mick Maghar
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING

Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.

Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of

which they are aware and to provide supporting documentation.
TITLE:

Workplace atmospheres – Part 2: Gas detectors – Selection, installation, use and maintenance of

detectors for toxic gases and vapours and oxygen
PROPOSED STABILITY DATE: 2025
NOTE FROM TC/SC OFFICERS:

Copyright © 2019 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to

download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National

Committee positions. You may not copy or "mirror" the file or printed version of the document, or any part of it, for

any other purpose without permission in writing from IEC.
---------------------- Page: 3 ----------------------
oSIST prEN IEC 62990-2:2019
31/1445/CDV – 2 – IEC CD 62990-2  IEC:2019
1 CONTENTS

2 FOREWORD ........................................................................................................................... 4

3 INTRODUCTION ..................................................................................................................... 6

4 1 Scope .............................................................................................................................. 7

5 2 Normative references ...................................................................................................... 7

6 3 Terms and definitions ...................................................................................................... 7

7 4 Properties and detection of toxic gases and vapours ..................................................... 12

8 4.1 Properties and detection .................................................................................. 12

9 4.2 The difference between detecting gases and vapours ...................................... 13

10 4.3 Effects of water vapour on detection ................................................................ 16

11 4.4 Effects of temperature and pressure on detection ............................................ 16

12 4.5 Effects of corrosion on detection ...................................................................... 16

13 4.6 Detection by oxygen deficiency measurement .................................................. 16

14 5 Measurement tasks ....................................................................................................... 17

15 5.1 General ............................................................................................................ 17

16 5.2 General gas detection (Safety Monitoring) ....................................................... 17

17 5.3 Exposure measurement (Health Monitoring) ..................................................... 18

18 6 Selection of equipment .................................................................................................. 19

19 6.1 General ............................................................................................................ 19

20 6.2 Performance and electrical tests ...................................................................... 20

21 6.3 Indication range, measuring range and uncertainty of measurement ................ 20

22 6.4 Selectivity requirements ................................................................................... 21

23 6.5 The influence of environmental conditions ....................................................... 22

24 6.6 The influence of electromagnetic interference .................................................. 22

25 6.7 Time of response and time of recovery ............................................................ 22

26 6.8 Time to alarm ................................................................................................... 23

27 6.9 Data logging .................................................................................................... 24

28 6.10 Instruction manual ........................................................................................... 25

29 7 Design and installation of fixed toxic gas detection systems .......................................... 25

30 7.1 General ............................................................................................................ 25

31 7.2 Basic considerations for the installation of fixed systems ................................. 26

32 7.3 Location of detection points ............................................................................. 27

33 7.4 Access for calibration and maintenance ........................................................... 31

34 7.5 Additional considerations for sample lines ........................................................ 32

35 7.6 Summary of considerations for the location of sensors or sampling points ....... 32

36 7.7 Installation of sensors ...................................................................................... 33

37 7.8 Integrity and safety of fixed systems ................................................................ 34

38 7.9 Commissioning ................................................................................................ 35

39 7.10 Operating instructions, plans and records ........................................................ 35

40 8 Operation of toxic gas detection equipment ................................................................... 36

41 8.1 Alarm setting.................................................................................................... 36

42 8.2 Operation of personal and portable equipment ................................................. 37

43 8.3 Operation of transportable and fixed equipment ............................................... 41

44 8.4 Sample lines and sampling probes ................................................................... 42

45 8.5 Accessories ..................................................................................................... 43

46 9 Maintenance and calibration .......................................................................................... 43

47 9.1 General ............................................................................................................ 43

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48 9.2 Sensor ............................................................................................................. 43

49 9.3 Flow systems of aspirated equipment............................................................... 44

50 9.4 Readout devices .............................................................................................. 44

51 9.5 Alarms ............................................................................................................. 44

52 9.6 Maintenance .................................................................................................... 45

53 9.7 Calibration ....................................................................................................... 45

54 9.8 Operation test .................................................................................................. 46

55 9.9 Records ........................................................................................................... 47

56 10 Training ......................................................................................................................... 47

57 10.1 General ............................................................................................................ 47

58 10.2 Operator training .............................................................................................. 47

59 10.3 Maintenance and calibration training ................................................................ 47

60 Annex A (Informative) Commonly used measurement principles .......................................... 49

61 A.1 General ............................................................................................................ 49

62 A.2 Chemiluminescence ......................................................................................... 49

63 A.3 Colorimetry ...................................................................................................... 50

64 A.4 Electrochemical ............................................................................................... 50

65 A.5 Flame-ionization .............................................................................................. 51

66 A.6 Gas chromatography ........................................................................................ 52

67 A.7 Infrared photometry ......................................................................................... 52

68 A.8 Ion mobility spectrometry ................................................................................. 53

69 A.9 Mass spectrometry ........................................................................................... 54

70 A.10 Photo-ionization ............................................................................................... 54

71 A.11 Semiconductor ................................................................................................. 55

72 A.12 Ultra-violet/visible photometry .......................................................................... 56

73 Bibliography: ......................................................................................................................... 58

75 Table A.1 – Chemiluminescence ........................................................................................... 49

76 Table A.2 – Colorimetry ........................................................................................................ 50

77 Table A.3 – Electrochemical ................................................................................................. 50

78 Table A.4 – Flame-ionization ................................................................................................ 51

79 Table A.5 – Infrared photometry ............................................................................................ 52

80 Table A.6 – Ion mobility spectrometry ................................................................................... 53

81 Table A.7 – Mass spectrometry ............................................................................................. 54

82 Table A.8 – Photo-ionization (PID) ........................................................................................ 54

83 Table A.9 – Semiconductor ................................................................................................... 55

84 Table A.10 – Ultra-violet/visible photometry .......................................................................... 56

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87 INTERNATIONAL ELECTROTECHNICAL COMMISSION
88 ____________
89 WORKPLACE ATMOSPHERES –
90 Part 2: Gas detectors –
91 Selection, installation, use and maintenance of detectors for toxic gases
92 and vapours
93 FOREWORD

94 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

95 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

96 international co-operation on all questions concerning standardization in the electrical and electronic fields. To

97 this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

98 Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

99 Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

100 in the subject dealt with may participate in this preparatory work. International, governmental and non-

101 governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

102 with the International Organization for Standardization (ISO) in accordance with conditions determined by

103 agreement between the two organizations.

104 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

105 consensus of opinion on the relevant subjects since each technical committee has representation from all

106 interested IEC National Committees.

107 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

108 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

109 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

110 misinterpretation by any end user.

111 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

112 transparently to the maximum extent possible in their national and regional publications. Any divergence

113 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

114 the latter.

115 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

116 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

117 services carried out by independent certification bodies.

118 6) All users should ensure that they have the latest edition of this publication.

119 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

120 members of its technical committees and IEC National Committees for any personal injury, property damage or

121 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

122 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

123 Publications.

124 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

125 indispensable for the correct application of this publication.

126 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

127 patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

128 International Standard ISO/IEC 62990-2 has been prepared by Joint Working Group (JWG) 45

129 of IEC technical committee 31: Equipment for explosive atmospheres and ISO technical

130 committee 146: Air quality, sub-committee 2: Workplace atmospheres.
131 The text of this standard is based on the following documents:
FDIS Report on voting
31/XX/FDIS 31/XX/RVD
132

133 Full information on the voting for the approval of this standard can be found in the report on

134 voting indicated in the above table.

135 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

136 The committee has decided that the contents of this publication will remain unchanged until

137 the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data

138 related to the specific publication. At this date, the publication will be
139 • reconfirmed,
140 • withdrawn,
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141 • replaced by a revised edition, or
142 • amended.

143 The National Committees are requested to note that for this publication the stability date

144 is ....

145 THIS TEXT IS INCLUDED FOR THE INFORMATION OF THE NATIONAL COMMITTEES AND WILL BE

146 DELETED AT THE PUBLICATION STAGE.
147
148
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149 INTRODUCTION

150 Toxic gas detection equipment may be used whenever there is the possibility of a hazard to

151 life or adverse health effects caused by the accumulation of a toxic gas or vapour. Such

152 equipment can provide a means of reducing the exposure to the hazard by detecting the

153 presence of a toxic gas or vapour and issuing suitable audible or visual warnings. Gas

154 detectors may also be used to initiate precautionary steps (e.g. plant shutdown and

155 evacuation).

156 Performance requirements for gas detection equipment for workplace atmospheres are set out

157 in ISO/IEC 62990-1 and ISO/IEC 62990-3.

158 However performance capability alone cannot ensure that the use of such equipment will

159 properly safeguard life and health where toxic gases and vapours may be present. The level

160 of safety obtained depends heavily upon correct selection, installation, calibration and

161 periodic maintenance of the equipment, combined with knowledge of the limitations of the

162 detection technique required. This cannot be achieved without responsible informed

163 management.

164 This standard has been specifically written to cover all the functions necessary from selection

165 to ongoing maintenance for a successful gas detection operation.
166
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167 WORKPLACE ATMOSPHERES –
168 Part 2: Gas detectors –
169 Selection, installation, use and maintenance of detectors for toxic gases
170 and vapours
171 1 Scope

172 This document gives guidance on the selection, installation, use and maintenance of electrical

173 equipment used for the direct detection and direct concentration measurement of toxic gases

174 and vapours in workplace atmospheres. The primary purpose of such equipment is to ensure

175 safety of personnel and property by providing an indication of the concentration of a toxic gas

176 or vapour and warning of its presence.

177 This document is applicable to equipment whose purpose is to provide an indication, alarm

178 and/or other output function to give a warning of the presence of a toxic gas or vapour in the

179 atmosphere and in some cases to initiate automatic or manual protective actions. It is

180 applicable to equipment in which the sensor automatically generates an electrical signal when

181 gas is present.
182 For the purposes of this document, equipment includes
183 a) fixed equipment;
184 b) transportable equipment, and
185 c) portable equipment.

186 This document is intended to cover equipment defined within ISO/IEC 62990-1, but may

187 provide useful information for equipment not covered by that document.
188 2 Normative references

189 The following documents are referred to in the text in such a way that some or all of their

190 content constitutes requirements of this document. For undated references, the latest edition

191 of the referenced document (including any amendments) applies.
192 ISO/IEC 62990-1, Workplace atmospheres – Part 1: Gas detectors – Performance
193 requirements of detectors for toxic gases

194 IEC 60079-10-1, Explosive atmospheres – Part 10-1: Classification of area – Explosive gas

195 atmospheres

196 IEC 60079-29-2, Explosive atmospheres – Part 29-2: Gas detectors – Selection, installation,

197 use and maintenance of detectors for flammable gases and oxygen

198 IEC 60079-0, Explosive atmospheres – Part 0: Equipment – General requirements

199 3 Terms and definitions

200 For the purposes of this document, the terms and definitions given in ISO/IEC 62990-1, as

201 well as the following apply. In addition, since this is intended as a stand-alone standard,

202 certain definitions within ISO/IEC 62990-1 are repeated below for the convenience of the

203 reader.

204 ISO and IEC maintain terminological databases for use in standardization at the following

205 addresses:
206 • IEC Electropedia: available at http://www.electropedia.org/
207 • ISO Online browsing platform: available at http://www.iso.org/obp

208 NOTE Additional definitions applicable to explosive atmospheres can be found in Chapter 426 of the International

209 Electrotechnical Vocabulary (IEV) IEC 60050 (426).
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210 3.1
211 toxic gas

212 gas or vapour that can be harmful to human health and/or the performance of persons due to

213 its physical or physico-chemical properties

214 Note 1 to entry: For the purpose of this document, the term “toxic gas” includes “toxic vapours”.

215 3.2
216 interfering gas

217 any gas other than the gas to be detected, including water vapour, which affects the indication

218 3.3
219 clean air

220 air that is free of gases or vapours which the sensor is sensitive to or which influence the

221 performance of the sensor
222 3.4
223 zero gas

224 gas recommended by the manufacturer, which is free of toxic gases and interfering and

225 contaminating substances, the purpose of which is calibration or adjustment of the equipment

226 zero
227 3.5
228 volume fraction

229 quotient of the volume of a specified component and the sum of the volumes of all

230 components of a gas mixture before mixing, all volumes referring to the pressure and the

231 temperature of the gas mixture

232 Note 1 to entry: The volume fraction and volume concentration take the same value if, at the same state

233 conditions, the sum of the component volumes before mixing and the volume of the mixture are equal. However,

234 because the mixing of two or more gases at the same state conditions is usually accompanied by a slight

235 contraction or, less frequently, a slight expansion, this is not generally the case.

236 3.6
237 occupational exposure limit value
238 OELV

239 limit of the time-weighted average of the concentration of a chemical agent in the air within

240 the breathing zone of a worker in relation to a specified reference period

241 Note 1 to entry: The term “limit value” is often used as a synonym for “occupational exposure limit value”, but the

242 term “occupational exposure limit value” is preferred because there is more than one limit value (e.g., biological

243 limit value and occupational exposure limit value).

244 Note 2 to entry: Occupational exposure limit values (OELVs) are often set for reference periods of 8 h, but can

245 also be set for shorter periods or concentration excursions.
246 [SOURCE: ISO 18158:2016, 2.1.5.4, modified (Note 2 to entry is shortened)]
247 3.7
248 exposure (by inhalation)

249 situation in which a chemical agent is present in air that is inhaled by a person

250 3.8
251 time weighted average concentration
252 TWA concentration
253 concentration of gas in air averaged over a reference period
254 3.9
255 fixed equipment

256 equipment fastened to a support, or otherwise secured in a specific location when energized

257 3.10
258 transportable equipment

259 equipment not intended to be carried by a person during operation, nor intended for fixed

260 installation
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261 3.11
262 portable equipment
263 equipment intended to be carried by a person during its operation

264 Note 1 to entry: Portable equipment is battery powered and includes, but is not limited to;

265 a) hand-held equipment, typically less than 1 kg, which requires use of only one hand to operate,

266 b) personal monitors, similar in size and mass to the hand-held equipment, that are continuously operating while

267 they are attached to the user, and,

268 c) larger equipment that can be operated by the user while it is carried either by hand, by a shoulder strap or

269 carrying harness and which may or may not have a hand directed probe.
270 3.12
271 personal equipment

272 portable equipment attached to a person that monitors the atmosphere in their breathing zone

273 so that their exposure to toxic gases can be determined
274 Note 1 to entry: Also known as a personal monitor.
275 3.13
276 aspirated equipment
277 equipment that samples the atmosphere by drawing it to the sensor

278 Note 1 to entry: A hand operated or electric pump is often used to draw gas to the sensor.

279 3.14
280 alarm-only equipment
281 equipment with an alarm but not having an indication of measured value
282 3.15
283 sensing element
284 part of the sensor which is sensitive to the gas/vapour to be measured
285 3.16
286 sensor

287 assembly in which the sensing element is housed and that may also contain associated circuit

288 components
289 3.17
290 remote sensor

291 sensor which is installed separately, but is connected to a gas detection control unit, gas

292 detection transmitter, or to transportable or portable equipment
293 3.18
294 gas detection transmitter

295 fixed gas detection equipment that provides a conditioned electronic signal or output

296 indication to a generally accepted industry standard (such as 4-20 mA), intended to be utilized

297 with separate gas detection control units or signal processing data acquisition, central

298 monitoring and similar systems, which typically process information from various locations

299 and sources including, but not limited to gas detection equipment
300 3.19
301 gas detection control unit

302 equipment intended to provide display indication, alarm functions, output contacts or alarm

303 signal outputs or any combination when operated with remote sensor(s)
304 3.20
305 alarm set point

306 setting of the equipment at which the measured concentration will cause the equipment to

307 initiate an indication, alarm or other output function
308 3.21
309 fault signal

310 audible, visible or other type of output, different from the alarm signal, permitting, directly or

311 indirectly, a warning or indication that the equipment is not working satisfactorily

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312 3.22
313 sample line
314 means by which the gas being sampled is conveyed to the sensor

315 Note 1 to entry: Accessories such as filter or water trap are often included in the sample line.

316 3.23
317 sampling probe
318 separate accessory sample line which is optionally attached to the equipment

319 Note 1 to entry: It is usually short (e.g. of the order of 1 m) and rigid, although it can be telescopic. In some cases

320 it is connected by a flexible tube to the equipment.
321 3.24
322 field calibration kit

323 means of presenting test gas to the equipment for the purpose of calibrating, adjusting or

324 verifying the operation of the equipment

325 Note 1 to entry: The field calibration kit can be used for verifying the operation of the alarms if the concentration

326 of the test gas is above the alarm set-point.

327 Note 2 to entry: A mask for calibration and test is an example of a field calibration kit.

328 3.25
329 zero indication

330 indication given by an equipment when exposed to zero gas in normal operating conditions

331 3.26
332 indication range

333 range of measured values of gas concentration over which the equipment is capable of

334 indicating (see Figure 1)
335 3.27
336 lower limit of indication
337 smallest measured value within the indication range (see Figure 2)
338 3.28
339 upper limit of indication
340 largest measured value within the indication range (see Figure 2)
341 3.29
342 measuring range

343 range of measured values of gas concentration over which the accuracy of the equipment lies

344 within specified limits (see Figure 2)
345 3.30
346 lower limit of measurement
347
...

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