IEC 62990-2:2021 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.<\/p>\n
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| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | Figures Figure 1 \u2013 Relationship between indication range and measuring range Figure 2 \u2013 Example of zero uncertainty <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | Figure 3 \u2013 Example of warm-up time in clean air <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 4 Properties and detection of toxic gases and vapours 4.1 Properties and detection <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 4.2 The difference between detecting gases and vapours 4.2.1 Gases <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 4.2.2 Vapours <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 4.3 Effects of water vapour on detection 4.4 Effects of temperature and pressure on detection 4.5 Effects of corrosion on detection 4.6 Detection by oxygen deficiency measurement <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 5 Measurement tasks 5.1 General 5.2 Exposure measurement (health monitoring) <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 5.3 General gas detection (safety monitoring) <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 6 Selection of equipment 6.1 General <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 6.2 Performance and electrical tests 6.3 Indication range, measuring range and uncertainty of measurement 6.3.1 General <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 6.3.2 Type HM (Health Monitoring) equipment 6.3.3 Type SM (Safety Monitoring) equipment 6.4 Selectivity requirements Figure 4 \u2013 Relationship between indication range and measuring range <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | 6.5 The influence of environmental conditions 6.6 The influence of electromagnetic interference <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | 6.7 Time of response and time of recovery Figure 5 \u2013 Gas response curves for test gas volume fractions of 40 ppm and 100 ppm <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 6.8 Time to alarm 6.9 Data logging Figure 6 \u2013 Time to alarm at 25 ppm set point for test gas volume fractionsof 40 ppm and 100 ppm <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 6.10 Instruction manual 7 Design and installation of fixed toxic gas detection equipment 7.1 General <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 7.2 Basic considerations for the installation of fixed systems <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | 7.3 Location of detection points 7.3.1 General 7.3.2 General site considerations <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | 7.3.3 Site conditions <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | 7.3.4 Environmental conditions <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | 7.4 Access for calibration and maintenance 7.5 Additional considerations for sample lines <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | 7.6 Summary of considerations for the location of sensors or sampling points <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | 7.7 Installation of sensors 7.8 Integrity and safety of fixed systems 7.8.1 General 7.8.2 Redundancy in fixed systems <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | 7.8.3 Protection against loss of main power supply 7.8.4 Timing of installation during construction operations 7.9 Commissioning 7.9.1 Inspection <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | 7.9.2 Initial gas calibration 7.9.3 Adjustment of alarm set points 7.10 Operating instructions, plans and records <\/td>\n<\/tr>\n | ||||||
| 43<\/td>\n | 8 Operation of toxic gas detection equipment 8.1 Alarm setting <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | 8.2 Operation of portable equipment 8.2.1 General <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | 8.2.2 Electrical protection in explosive atmospheres 8.2.3 Safety of personnel 8.2.4 Spot tests and sampling 8.2.5 Sampling above liquids <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | 8.2.6 Avoidance of condensation 8.2.7 Poisoning of sensors 8.2.8 Changes of temperature 8.2.9 Accidental damage 8.2.10 \u201cRead and run\u201d concept <\/td>\n<\/tr>\n | ||||||
| 47<\/td>\n | 8.2.11 Transportation 8.2.12 Storage 8.2.13 Inspection and functional checks <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | 8.3 Operation of transportable and fixed equipment 8.3.1 General <\/td>\n<\/tr>\n | ||||||
| 49<\/td>\n | 8.3.2 Commissioning and regular inspection <\/td>\n<\/tr>\n | ||||||
| 50<\/td>\n | 8.4 Sample lines and sampling probes 8.5 Accessories <\/td>\n<\/tr>\n | ||||||
| 51<\/td>\n | 9 Maintenance and calibration 9.1 General 9.2 Sensor 9.2.1 General 9.2.2 Flame arrestor 9.3 Flow systems of aspirated equipment 9.3.1 General 9.3.2 Filters, traps and flame arrestors 9.3.3 Flow system and sample chamber 9.3.4 Flow connections <\/td>\n<\/tr>\n | ||||||
| 52<\/td>\n | 9.3.5 Moving parts 9.3.6 Automatic sample-draw systems 9.3.7 Loss-of-flow signals 9.4 Readout devices 9.4.1 General 9.4.2 Other readouts 9.5 Alarms 9.6 Maintenance <\/td>\n<\/tr>\n | ||||||
| 53<\/td>\n | 9.7 Calibration 9.7.1 Procedure <\/td>\n<\/tr>\n | ||||||
| 54<\/td>\n | 9.7.2 Calibration period 9.8 Operation test <\/td>\n<\/tr>\n | ||||||
| 55<\/td>\n | 9.9 Records 10 Training 10.1 General 10.2 Operator training <\/td>\n<\/tr>\n | ||||||
| 56<\/td>\n | 10.3 Maintenance and calibration training <\/td>\n<\/tr>\n | ||||||
| 57<\/td>\n | Annex A (informative)Commonly used measurement principles A.1 General A.2 Chemiluminescence Tables Table A.1 \u2013 Chemiluminescence <\/td>\n<\/tr>\n | ||||||
| 58<\/td>\n | A.3 Colorimetry Table A.2 \u2013 Colorimetry <\/td>\n<\/tr>\n | ||||||
| 59<\/td>\n | A.4 Electrochemical Table A.3 \u2013 Electrochemical <\/td>\n<\/tr>\n | ||||||
| 60<\/td>\n | A.5 Flame-ionization A.6 Gas chromatography Table A.4 \u2013 Flame-ionization <\/td>\n<\/tr>\n | ||||||
| 61<\/td>\n | A.7 Infrared photometry Table A.5 \u2013 Infrared photometry <\/td>\n<\/tr>\n | ||||||
| 62<\/td>\n | A.8 Ion mobility spectrometry Table A.6 \u2013 Ion mobility spectrometry <\/td>\n<\/tr>\n | ||||||
| 63<\/td>\n | A.9 Mass spectrometry Table A.7 \u2013 Mass spectrometry <\/td>\n<\/tr>\n | ||||||
| 64<\/td>\n | A.10 Photo-ionization Table A.8 \u2013 Photo-ionization (PID) <\/td>\n<\/tr>\n | ||||||
| 65<\/td>\n | A.11 Semiconductor Table A.9 \u2013 Semiconductor <\/td>\n<\/tr>\n | ||||||
| 66<\/td>\n | A.12 Ultra-violet\/visible photometry Table A.10 \u2013 Ultra-violet\/visible photometry <\/td>\n<\/tr>\n | ||||||
| 67<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Workplace atmospheres – Gas detectors. Selection, installation, use and maintenance of detectors for toxic gases and vapours<\/b><\/p>\n |