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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
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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
– 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
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
– 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
...