This part of ISO\/IEC 80079 provides guidance on classification of gases and vapours. It describes a test method intended for the measurement of the maximum experimental safe gaps (MESG) for gas-air mixtures or vapour-air mixtures under normal conditions of temperature and pressure (20 \u00b0C, 101,3 kPa) so as to permit the selection of an appropriate group of equipment. This document also describes a test method intended for use in the determination of the auto-ignition temperature (AIT) of a vapour-air mixture or gas-air mixture at atmospheric pressure, so as to permit the selection of an appropriate temperature class of equipment.<\/p>\n
Values of chemical properties of materials are provided to assist in the selection of equipment to be used in hazardous areas. Further data may be added as the results of validated tests become available.<\/p>\n
The materials and the characteristics included in a table (see Annex B) have been selected with particular reference to the use of equipment in hazardous areas. The data in this document have been taken from a number of references which are given in the bibliography.<\/p>\n
These methods for determining the MESG or the AIT may also be used for gas-air-inert mixtures or vapour-air-inert mixtures. However, data on air-inert mixtures are not tabulated.<\/p>\n
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| 2<\/td>\n | undefined <\/td>\n<\/tr>\n | ||||||
| 4<\/td>\n | European foreword Endorsement notice <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Annex ZA <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 1 Scope 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 4 Classification of gases and vapours 4.1 General 4.2 Classification according to the maximum experimental safe gap (MESG) <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 4.3 Classification according to the minimum igniting current ratio (MIC ratio) 4.4 Classification according to the similarity of chemical structure 4.5 Classification of mixtures of gases <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 5 Data for flammable gases and vapours, relating to the use of equipment 5.1 Determination of the properties 5.1.1 General 5.1.2 Equipment group 5.1.3 Flammable limits 5.1.4 Flash point (FP) <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 5.1.5 Temperature class 5.1.6 Minimum igniting current (MIC) 5.1.7 Auto-ignition temperature (AIT) 5.2 Properties of particular gases and vapours 5.2.1 Coke oven gas 5.2.2 Ethyl nitrite 5.2.3 MESG of carbon monoxide Tables Table 1 \u2212 Classification of temperature class and range of auto-ignition temperatures <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 5.2.4 Methane, Equipment Group IIA 6 Method of test for the maximum experimental safe gap (MESG) 6.1 Outline of method 6.2 Test apparatus 6.2.1 General Figures Figure 1 \u2212 Test apparatus <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 6.2.2 Material and mechanical strength 6.2.3 Exterior chamber 6.2.4 Interior chamber 6.2.5 Gap adjustment 6.2.6 Injection of mixture 6.2.7 Position of ignition source 6.3 Procedure 6.3.1 Preparation of gas mixtures 6.3.2 Temperature and pressure <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 6.3.3 Gap adjustment 6.3.4 Ignition 6.3.5 Observation of the ignition process 6.4 Determination of maximum experimental safe gap (MESG) 6.4.1 General 6.4.2 Preliminary tests 6.4.3 Confirmatory tests 6.4.4 Reproducibility of maximum experimental safe gaps (MESG) <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 6.4.5 Tabulated values 6.5 Verification of the MESG determination method 7 Method of test for auto-ignition temperature (AIT) 7.1 Outline of method 7.2 Apparatus 7.2.1 General Table 2 \u2212 Values for verification of the apparatus <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 7.2.2 Test vessel and support 7.2.3 Thermocouples 7.2.4 Oven <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 7.2.5 Metering devices 7.2.6 Mirror 7.2.7 Timer 7.2.8 Equipment for purging the test vessel with air 7.2.9 Automated apparatus <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 7.3 Sampling, preparation and preservation of test samples 7.3.1 Sampling 7.3.2 Preparation and preservation 7.4 Procedure 7.4.1 General <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 7.4.2 Sample injection 7.4.3 Determination of the auto-ignition temperature (AIT) <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | 7.5 Auto-ignition temperature (AIT) 7.6 Validity of results 7.6.1 Repeatability 7.6.2 Reproducibility <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 7.7 Data 7.8 Verification of the auto-ignition temperature determination method Table 3 \u2212 Values for verification of the apparatus <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Annex A (normative)Ovens of test apparatus for the tests of auto-ignition temperature <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | Figure A.1 \u2212 Test apparatus: assembly <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | Figure A.2 \u2212 Section A-A (flask omitted) Figure A.3 \u2212 Base heater (board made of refractory material) <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | Figure A.4 \u2212 Flask guide ring (board made of refractory material) Figure A.5 \u2212 Neck heater (board made of refractory material) <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | Figure A.6 \u2212 Oven <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | Figure A.7 \u2212 Lid of steel cylinder <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Figure A.8 \u2212 Lid of steel cylinder Figure A.9 \u2212 Injection of gaseous sample <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Annex B (informative)Tabulated values <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Table B.1 \u2212 Material data <\/td>\n<\/tr>\n | ||||||
| 89<\/td>\n | Annex C (informative)Determination of cool flames Figure C.1 \u2212 Additional thermocouple to detect cool flames <\/td>\n<\/tr>\n | ||||||
| 90<\/td>\n | Figure C.2 \u2212 \u2018Negative temperature coefficient\u2019 shown for butyl butyrate as an example <\/td>\n<\/tr>\n | ||||||
| 91<\/td>\n | Annex D (informative)Volume dependence of auto-ignition temperature Figure D.1 \u2212 Volume dependence of auto-ignition temperature <\/td>\n<\/tr>\n | ||||||
| 92<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Explosive atmospheres – Material characteristics for gas and vapour classification. Test methods and data<\/b><\/p>\n |