AS/NZS 2381.1:2005

1 - AS/NZS 2381.1:2005 ELECTRICAL EQUIPMENT FOR EXPLOSIVE GAS ATMOSPHERES-SELECTION, INSTALLATION AND MAINTENANCE - GENERAL...
4 - PREFACE
5 - CONTENTS
7 - FOREWORD
8 - SECTION 1 SCOPE AND GENERAL
8 - 1.1 SCOPE
8 - 1.2 APPLICATION
8 - 1.3 REFERENCED DOCUMENTS
9 - 1.4 DEFINITIONS
9 - 1.4.1 Approved, approval
9 - 1.4.2 Area
9 - 1.4.3 Area, hazardous
9 - 1.4.4 Area, non-hazardous
9 - 1.4.5 Authority, authority having jurisdiction
9 - 1.4.6 Cable trunking system
9 - 1.4.7 Canned pump
9 - 1.4.8 Chemical compatibility
9 - 1.4.9 Competent person
9 - 1.4.10 Degree of protection of enclosures
9 - 1.4.11 Earth sheath return (ESR) system
10 - 1.4.12 Electrical apparatus
10 - 1.4.13 Equipotential bonding
10 - 1.4.14 Ex component
10 - 1.4.15 Explosive atmosphere
10 - 1.4.16 Explosion-protection
10 - 1.4.17 Flammable gas or vapour
10 - 1.4.18 Flammable liquid
10 - 1.4.19 Flammable material
11 - 1.4.20 Flashpoint
11 - 1.4.21 Hazard
11 - 1.4.22 Heavy maintenance ('base maintenance')
11 - 1.4.23 Ignition source
11 - 1.4.24 Ignition temperature (of an explosive gas atmosphere)
11 - 1.4.25 Inherently explosive
11 - 1.4.26 Inspection
12 - 1.4.27 Instrument
12 - 1.4.28 Lower explosive limit (LEL)
12 - 1.4.29 Maintenance
12 - 1.4.30 Maximum surface temperature
12 - 1.4.31 Non-incendive equipment
12 - 1.4.32 Pyrophoric
12 - 1.4.33 Overhaul
12 - 1.4.34 Repair
12 - 1.4.35 Source of release
13 - 1.4.36 Temperature classification
13 - 1.4.37 Unprotected surface
13 - 1.4.38 Upper explosive limit (UEL)
13 - 1.4.39 Verification dossier
13 - 1.4.40 Wiring, open
13 - 1.4.41 Zones, hazardous
13 - 1.4.42 Zones in explosive gas atmospheres
13 - 1.5 STATUTORY REGULATIONS
13 - 1.6 DOCUMENTATION
14 - 1.7 QUALIFICATIONS OF PERSONNEL
14 - 1.8 CLASSIFICATION OF HAZARDOUS AREAS
15 - 1.9 OTHER CONSIDERATIONS
15 - 1.9.1 Protection from mechanical damage and environmental injury influences
15 - 1.9.2 Ambient temperature
15 - 1.9.3 Use of aluminium or light alloys
15 - 1.9.4 Toxic risks
15 - 1.9.5 Non-electrical ignition sources
15 - 1.9.6 Static electricity
15 - 1.9.7 Lightning
16 - 1.9.8 Electromagnetic radiation
16 - 1.9.9 Radiation from optical equipment
16 - 1.9.10 Cathodic protection
16 - 1.9.11 Personal equipment
16 - 1.10 PREVENTION OF EXPLOSION
16 - 1.10.1 General
17 - 1.10.2 Suppression or avoidance
17 - 1.10.3 Explosion-protected electrical equipment
17 - 1.10.4 Conditions of control
17 - 1.11 PRECAUTIONS
17 - 1.11.1 General
18 - 1.11.2 Equipment rendered ‘not alive’
18 - 1.11.3 Equipment not rendered ‘not alive’
18 - 1.11.4 Igniting agencies
19 - SECTION 2 SELECTION OF ELECTRICAL EQUIPMENT
19 - 2.1 SCOPE OF SECTION
19 - 2.2 SPECIFIC EQUIPMENT NOT PERMITTED IN HAZARDOUS AREAS
19 - 2.3 PERMITTED EQUIPMENT
19 - 2.4 ZONE 0, 1 AND 2 HAZARDOUS AREAS
19 - 2.4.1 Required information
20 - 2.4.2 Selection with respect to area classification
20 - 2.4.3 Selection with respect to temperature classification
22 - 2.4.4 Selection with respect to equipment grouping
23 - 2.4.5 Enclosures with internal sources of release
23 - 2.4.6 Motors supplied at varying frequency and voltages
23 - 2.4.7 Trace heating
23 - 2.5 ZONES 20, 21 AND 22 HAZARDOUS AREAS
23 - 2.6 ASSURANCE OF CONFORMITY OF APPARATUS
23 - 2.6.1 Use of certified apparatus
24 - 2.6.2 Other acceptable certification
25 - 2.7 SELECTION OF REPAIRED OR EXISTING EQUIPMENT
27 - SECTION 3 INSTALLATION
27 - 3.1 SCOPE OF SECTION
27 - 3.2 GENERAL INSTALLATION REQUIREMENTS
27 - 3.2.1 General
27 - 3.2.2 Access
27 - 3.2.3 Electrical rating
27 - 3.2.4 Associated equipment located in non-hazardous areas
27 - 3.2.5 Intrinsically safe installations
27 - 3.2.6 Equipment identification
27 - 3.3 EARTHING
27 - 3.3.1 General
28 - 3.3.2 Enclosure and termination of earthing conductors
28 - 3.3.3 Earthing of spare conductors
29 - 3.3.4 Earthing of aircraft
29 - 3.4 EQUIPOTENTIAL BONDING
29 - 3.4.1 General
29 - 3.4.2 Temporary bonding
29 - 3.4.3 Bonding of metallic enclosures, conduits, sheaths and armour
29 - 3.5 ELECTRICAL PROTECTION*
29 - 3.5.1 General
30 - 3.5.2 Location of protection and control equipment
30 - 3.5.3 Resetting of short-circuit and earth-fault protection devices
30 - 3.5.4 Phase failure protection
30 - 3.6 ELECTRICAL ISOLATION
30 - 3.7 EMERGENCY SWITCH-OFF*
30 - 3.8 WIRING SYSTEMS-GENERAL REQUIREMENTS
30 - 3.8.1 Specific methods not permitted
31 - 3.8.2 Permitted types
31 - 3.8.3 Telecommunications circuits
31 - 3.8.4 Avoidance of damage
32 - 3.8.5 Passage and collection of flammables
33 - 3.8.6 Circuits traversing a hazardous area
33 - 3.8.7 Fortuitous contact
33 - 3.8.8 Flexible connections to fixed equipment*
33 - 3.8.9 Surge protection of circuits supplied from overhead lines
33 - 3.8.10 Wiring entry
33 - 3.8.11 Unused entries
33 - 3.8.12 Jointing
34 - 3.8.13 Protection of stranded ends
34 - 3.8.14 Glands and seals
34 - 3.8.15 Conduit systems
36 - 3.8.16 Equipment circuit identification
36 - 3.9 EQUIPMENT - GENERAL REQUIREMENTS
36 - 3.9.1 Installation of equipment
36 - 3.9.2 Lighting
36 - 3.9.3 Fastenings and tools
37 - 3.9.4 Equipment above hazardous areas
38 - 3.9.5 Non-electric entries
38 - 3.9.6 Plugs
38 - 3.9.7 Motors
38 - 3.10 ADDITIONAL REQUIREMENTS FOR INSTALLATIONS IN ZONE 0 AREAS
38 - 3.10.1 Flexible cable systems
38 - 3.10.2 Conduit systems
38 - 3.11 ADDITIONAL REQUIREMENTS FOR INSTALLATIONS IN ZONE 1 AREAS
38 - 3.11.1 Flexible connections
39 - 3.11.2 Plugs and socket-outlets
39 - 3.11.3 Pendant luminaires
40 - 3.11.4 Heating cables
40 - 3.12 ADDITIONAL REQUIREMENTS FOR INSTALLATIONS IN ZONE 2 AREAS
40 - 3.12.1 Wiring systems
40 - 3.12.2 Pendant luminaires
40 - 3.13 SPECIFIC OCCUPANCIES
40 - 3.13.1 General
40 - 3.13.2 Ovens
40 - 3.13.3 Fuel dispensing
41 - 3.13.4 Finishing processes
43 - 3.13.5 Laboratory fume cupboards
43 - 3.13.6 Secondary batteries in buildings
44 - 3.14 TRACE HEATING
45 - SECTION 4 INSPECTION AND TESTING INCLUDING COMMISSIONING
45 - 4.1 GENERAL
45 - 4.2 DOCUMENTATION
45 - 4.3 INSPECTION
45 - 4.3.1 General
48 - 4.3.2 Identification of equipment certification
48 - 4.3.3 Types of inspection
49 - 4.3.4 Grades of inspection
49 - 4.4 ITEMS REQUIRING INSPECTION
49 - 4.5 TESTING
49 - 4.5.1 General
49 - 4.5.2 Pre-commissioning tests
50 - SECTION 5 MAINTENANCE
50 - 5.1 SCOPE OF SECTION
50 - 5.2 REMEDIAL MEASURES AND MODIFICATIONS TO EQUIPMENT
50 - 5.3 MAINTENANCE OF FLEXIBLE CABLES
50 - 5.4 WITHDRAWAL FROM SERVICE
50 - 5.5 FASTENINGS AND TOOLS
50 - 5.6 ENVIRONMENTAL CONDITIONS
51 - 5.7 EARTHING AND EQUIPOTENTIAL BONDING
51 - 5.8 CONDITIONS OF USE
51 - 5.9 MOVABLE EQUIPMENT AND ITS CONNECTIONS
51 - 5.10 OVERHAUL AND REPAIR
52 - APPENDIX A - LIST OF REFERENCED DOCUMENTS
55 - APPENDIX B - STATEMENT OF PERIODIC VERIFICATION (NEW ZEALAND ONLY)
56 - APPENDIX C - FRICTIONAL SPARKING RISKS WITH LIGHT METALS* AND THEIR ALLOYS
56 - C1 GENERAL
56 - C2 RIGIDLY MOUNTED EQUIPMENT
56 - C3 PORTABLE AND TRANSPORTABLE EQUIPMENT
56 - C4 FANS
57 - C5 ALUMINIUM CONDUCTORS
58 - APPENDIX D - REPORT ON THE DANGER FROM HIGH-INTENSITY LIGHT SOURCES IN HAZARDOUS ATMOSPHERES
58 - D1 INTRODUCTION
58 - D2 BREADTH OF EXPERIMENTAL INVESTIGATIONS
59 - D3 REFERENCE EXPERIMENTS
59 - D4 CORRELATION WITH KNOWN IGNITION PARAMETERS
61 - D5 PREDICTIVE COMPUTATIONS
61 - D6 LIMITING SAFETY CRITERIA AND COMPARISON WITH EXPERIMENTAL RESULTS
62 - D7 CONCLUSIONS
66 - APPENDIX E - PROPERTIES OF FLAMMABLE LIQUIDS, VAPOURS AND GASES
66 - E1 SCOPE
66 - E2 FLASHPOINT
66 - E2.1 General
66 - E2.2 Materials having high flashpoints
66 - E2.3 Classification of flashpoints
67 - E3 IGNITION TEMPERATURE
67 - E3.1 General
67 - E3.2 Use of ignition temperature
67 - E4 EXPLOSIVE (FLAMMABLE) LIMITS
67 - E5 EXPLOSIVE (FLAMMABILITY) RANGE
67 - E6 VAPOUR DENSITY
67 - E6.1 General
68 - E6.2 Effects of temperature changes
68 - E7 BOILING POINT
68 - E8 TEMPERATURE CLASSIFICATION
68 - E9 CLASSIFICATION OF GASES AND VAPOURS
68 - E9.1 General
69 - E9.2 Classification according to the Maximum Experimental Safe Gaps (MESG)
69 - E9.3 Classification according to the Minimum Igniting Currents (MIC)
69 - E9.4 Classification according to MESG and MIC
69 - E9.5 Classification according to a similarity of chemical structure
70 - E10 GENERAL CONSIDERATIONS
70 - E10.1 Relation between ignition temperature and maximum surface temperature
70 - E10.2 Mixtures of compounds
71 - E10.3 Mists
71 - E10.4 Impurities
71 - E10.5 Effect of environments having other than normal atmospheric conditions
72 - APPENDIX F - ENCLOSURES WITH INTERNAL SOURCES OF RELEASE
72 - F1 GENERAL
72 - F2 TYPE AND EXTENT OF INTERNAL RELEASE
73 - F3 COMBINATION OF TYPES OF RELEASE
73 - F3.1 General
74 - F4 EFFECT OF THE COMBINATIONS OF TYPES OF RELEASE ON AREA CLASSIFICATION
75 - F5 PROTECTION FOR ENCLOSURES CONTAINING A SOURCE OF RELEASE
75 - F5.1 Types of enclosure
75 - F5.2 Flameproof enclosure
75 - F5.3 Pressurized and continuously diluted enclosures
75 - F5.4 Other enclosures
75 - F6 SELECTION OF A TYPE OF EXPLOSION-PROTECTION
75 - F6.1 For enclosures containing a source of release
76 - F6.2 Using Table F1
78 - APPENDIX G - REQUIREMENTS FOR ACCEPTABLE CERTIFICATION SCHEMES FOR EXPLOSION-PROTECTED ELECTRICAL EQUIPMENT (TERMED Ex EQUIPMENT)
78 - G1 INTRODUCTION
78 - G2 REQUIREMENTS FOR AN ACCEPTABLE EX CERTIFICATION SYSTEM
79 - APPENDIX H - CALCULATION OF THE EXPLOSIVE LIMITS FOR A MIXTURE OF GASES
79 - H1 LIMITS FOR SIMPLE MIXTURES
80 - H2 LIMITS FOR COMPLEX INDUSTRIAL GAS MIXTURES
84 - APPENDIX I - INFORMATION RELATING TO AUSEx, ANZEx AND IECEx CERTIFICATION SCHEMES
84 - I1 THE AUSEx SCHEME
84 - I2 THE ANZEx SCHEME
85 - I3 THE IECEx SCHEME

Specifies general requirements for the selection, installation and maintenance of electrical equipment for use in areas were flammable materials are generated, prepared, processed, handled, stored or otherwise used, and which are therefore potentially hazardous.

This Standard specifies general requirements, additional to those required for basic electrical safety, for the selection of electrical equipment and instruments, and associated equipment, and for the electrical equipment’s installation and maintenance to ensure safe use in hazardous areas where flammable materials are generated, prepared, processed, handled, stored or otherwise used.This Standard does not apply to those materials which are specifically manufactured as explosives, or to materials which are inherently explosive or pyrophoric. Explosive materials may require special considerations which are beyond the scope of this Standard.The requirements of this Standard apply only to the use of electrical equipment under normal or near normal atmospheric conditions. For other conditions, additional precautions may be necessary. For example, most flammable materials and many materials which are normally regarded as non-flammable might burn vigorously under conditions of oxygen enrichment. Other precautions might also be necessary in the use of electrical equipment under conditions of extreme temperature and pressure. Such precautions are beyond the scope of this Standard.Precautions which may be necessary against the effects of static electricity and against lightning are also outside the scope of this Standard, except for the general recommendations indicated in Clause 1.9.

Originated in Australia as AS 1076.1-1977.
Revised and redesignated as AS 2381.1-1991.
Jointly revised and redesignated as AS/NZS 2381.1:1999.
Third edition 2005.