AS/NZS 2381.1:1999

IMPORTANT NOTE

This special edition of AS 2381.1-99 has been re-edited so that the extensive changes required by Amendment 1 (March 2003) have been incorporated within the Standard.

If you would prefer to purchase a printed copy of the original 1999 publication, accompanied by a separate copy of Amendment 1, CLICK HERE.

1 - AS/NZS 2381.1:1999 ELECTRICAL EQUIPMENT FOR EXPLOSIVE ATMOSPHERES-SELECTION, INSTALLATION AND MAINTENANCE - GENERAL...
4 - PREFACE
6 - CONTENTS
8 - FOREWORD
9 - SECTION 1 SCOPE AND GENERAL
9 - 1.1 SCOPE
9 - 1.2 APPLICATION
9 - 1.3 REFERENCED DOCUMENTS
10 - 1.4 DEFINITIONS
10 - 1.4.1 Approved, approval
10 - 1.4.2 Area
10 - 1.4.3 Area, hazardous
10 - 1.4.4 Area, non-hazardous
10 - 1.4.5 Authority, authority having jurisdiction
10 - 1.4.6 Cable trunking system
10 - 1.4.7 Canned pump
10 - 1.4.8 Chemical compatibility
10 - 1.4.9 Cloud ignition temperature (of dusts)
10 - 1.4.10 Combustible dust
10 - 1.4.11 Competent person
10 - 1.4.12 Degree of protection of enclosures
11 - 1.4.13 Earth sheath return (ESR) system
11 - 1.4.14 Electrical apparatus
11 - 1.4.15 Equipotential bonding
11 - 1.4.16 Ex component
11 - 1.4.17 Explosive atmosphere
11 - 1.4.18 Explosion-protection
11 - 1.4.19 Flammable gas or vapour
11 - 1.4.20 Flammable liquid
11 - 1.4.21 Flammable material
12 - 1.4.22 Flashpoint
12 - 1.4.23 Hazard
12 - 1.4.24 Heavy maintenance ('base maintenance')
12 - 1.4.25 Ignition source
12 - 1.4.26 Ignition temperature (of an explosive gas atmosphere)
12 - 1.4.27 Inherently explosive
12 - 1.4.28 Inspection
13 - 1.4.29 Instrument
13 - 1.4.30 Layer ignition temperature (of dusts)
13 - 1.4.31 Lower explosive limit (LEL)
13 - 1.4.32 Maintenance
13 - 1.4.33 Maximum surface temperature
13 - 1.4.34 Minimum dust cloud ignition energy
13 - 1.4.35 Non-incendive equipment
13 - 1.4.36 Pyrophoric
13 - 1.4.37 Overhaul
14 - 1.4.38 Repair
14 - 1.4.39 Source of release
14 - 1.4.40 Temperature classification
14 - 1.4.41 Unprotected surface
14 - 1.4.42 Upper explosive limit (UEL)
14 - 1.4.43 Verification dossier
14 - 1.4.44 Wiring, open
14 - 1.4.45 Zones, hazardous
14 - 1.4.46 Zones in explosive gas atmospheres
14 - 1.4.47 Zones in explosive dust atmospheres
14 - 1.5 STATUTORY REGULATIONS
14 - 1.6 DOCUMENTATION
15 - 1.7 QUALIFICATIONS OF PERSONNEL
16 - 1.8 CLASSIFICATION OF HAZARDOUS AREAS
16 - 1.9 OTHER CONSIDERATIONS
16 - 1.9.1 Protection from mechanical damage and environmental injury influences
16 - 1.9.2 Ambient temperature
16 - 1.9.3 Use of aluminium or light alloys
16 - 1.9.4 Toxic risks
16 - 1.9.5 Non-electrical ignition sources
17 - 1.9.6 Static electricity
17 - 1.9.7 Lightning
17 - 1.9.8 Electromagnetic radiation
17 - 1.9.9 Radiation from optical equipment
17 - 1.9.10 Cathodic protection
17 - 1.9.11 Personal equipment
18 - 1.10 PREVENTION OF EXPLOSION
18 - 1.10.1 General
18 - 1.10.2 Suppression or avoidance
18 - 1.10.3 Explosion-protected electrical equipment
18 - 1.10.4 Conditions of control
19 - 1.11 PRECAUTIONS
19 - 1.11.1 General
19 - 1.11.2 Equipment rendered 'not alive'
19 - 1.11.3 Equipment not rendered 'not alive'
19 - 1.11.4 Igniting agencies
20 - SECTION 2 SELECTION OF ELECTRICAL EQUIPMENT
20 - 2.1 SCOPE OF SECTION
20 - 2.2 SPECIFIC EQUIPMENT NOT PERMITTED IN HAZARDOUS AREAS
20 - 2.3 PERMITTED EQUIPMENT
20 - 2.4 ZONE 0, 1 AND 2 HAZARDOUS AREAS
20 - 2.4.1 Required information
21 - 2.4.2 Selection with respect to area classification
21 - 2.4.3 Selection with respect to temperature classification
23 - 2.4.4 Selection with respect to equipment grouping
23 - 2.4.5 Enclosures with internal sources of release
24 - 2.4.6 Motors supplied at varying frequency and voltages
24 - 2.4.7 Trace heating
24 - 2.5 ZONE 20, 21 AND 22 HAZARDOUS AREAS
24 - 2.5.1 Information required
25 - 2.5.2 Selection with respect to area classification
25 - 2.5.3 Selection with respect to temperature classification
25 - 2.5.4 Types of explosion-protection
26 - 2.5.5 Motors supplied at varying frequency and voltages
26 - 2.5.6 Heating equipment
27 - 2.6 VERIFICATION OF ACCEPTANCE OF ELECTRICAL EQUIPMENT
27 - 2.6.1 General requirements for both Australia and New Zealand
27 - 2.6.2 Other acceptable certification
27 - 2.7 SELECTION OF REPAIRED OR EXISTING EQUIPMENT
29 - SECTION 3 INSTALLATION
29 - 3.1 SCOPE OF SECTION
29 - 3.2 GENERAL INSTALLATION REQUIREMENTS
29 - 3.2.1 General
29 - 3.2.2 Access
29 - 3.2.3 Electrical rating
29 - 3.2.4 Associated equipment located in non-hazardous areas
29 - 3.2.5 Intrinsically safe installations
29 - 3.3 EARTHING
29 - 3.3.1 General
29 - 3.3.2 Enclosure and termination of earthing conductors
30 - 3.3.3 Earthing of spare conductors
30 - 3.3.4 Earthing of aircraft
30 - 3.4 EQUIPOTENTIAL BONDING
30 - 3.4.1 General
31 - 3.4.2 Temporary bonding
31 - 3.4.3 Bonding of metallic enclosures, conduits, sheaths and armour
31 - 3.5 ELECTRICAL PROTECTION
31 - 3.5.1 General
31 - 3.5.2 Location of protection and control equipment
31 - 3.5.3 Resetting of short-circuit and earth-fault protection devices
31 - 3.5.4 Phase failure protection
31 - 3.6 ELECTRICAL ISOLATION
32 - 3.7 EMERGENCY SWITCH-OFF
32 - 3.8 WIRING SYSTEMS-GENERAL REQUIREMENTS
32 - 3.8.1 Specific methods not permitted
33 - 3.8.2 Permitted types
33 - 3.8.3 Telecommunications circuits
33 - 3.8.4 Avoidance of damage
34 - 3.8.5 Passage and collection of flammables
35 - 3.8.6 Circuits traversing a hazardous area
35 - 3.8.7 Fortuitous contact
35 - 3.8.8 Flexible connections to fixed equipment
35 - 3.8.9 Surge protection of circuits supplied from overhead lines
35 - 3.8.10 Wiring entry
35 - 3.8.11 Unused entries
35 - 3.8.12 Jointing
36 - 3.8.13 Protection of stranded ends
36 - 3.8.14 Glands and seals
36 - 3.8.15 Conduit systems
38 - 3.8.16 Equipment circuit identification
38 - 3.9 EQUIPMENT - GENERAL REQUIREMENTS
38 - 3.9.1 Installation of equipment
38 - 3.9.2 Lighting
38 - 3.9.3 Fastenings and tools
39 - 3.9.4 Equipment above hazardous areas
40 - 3.9.5 Non-electric entries
40 - 3.9.6 Plugs
40 - 3.9.7 Motors
40 - 3.10 ADDITIONAL REQUIREMENTS FOR INSTALLATIONS IN ZONE 0 AREAS
40 - 3.10.1 Flexible cable systems
40 - 3.10.2 Conduit systems
40 - 3.11 ADDITIONAL REQUIREMENTS FOR INSTALLATIONS IN ZONE 1 AREAS
40 - 3.11.1 Flexible connections
41 - 3.11.2 Cable glands
42 - 3.11.3 Plugs and socket-outlets
42 - 3.11.4 Pendant luminaires
42 - 3.11.5 Heating cables
42 - 3.12 ADDITIONAL REQUIREMENTS FOR INSTALLATIONS IN ZONE 2 AREAS
42 - 3.12.1 Wiring systems
43 - 3.12.2 Pendant luminaires
43 - 3.13 ADDITIONAL REQUIREMENTS FOR INSTALLATIONS IN ZONE 20, 21 AND 22 AREAS
43 - 3.13.1 Wiring systems
43 - 3.13.2 Flexible connections
43 - 3.13.3 Cable glands/entries
43 - 3.13.4 Dielectrics having a flashpoint exceeding 250°C
43 - 3.13.5 Luminaires
43 - 3.13.6 Pendant luminaires
44 - 3.13.7 Plugs and socket-outlets
44 - 3.14 SPECIFIC OCCUPANCIES
44 - 3.14.1 General
44 - 3.14.2 Ovens
44 - 3.14.3 Fuel dispensing
44 - 3.14.4 Finishing processes
47 - 3.14.5 Flammable medical agents
47 - 3.14.6 Laboratory fume cupboards
47 - 3.14.7 Secondary batteries in buildings
47 - 3.15 TRACE HEATING
48 - SECTION 4 INSPECTION AND TESTING INCLUDING COMMISSIONING
48 - 4.1 GENERAL
48 - 4.2 DOCUMENTATION
48 - 4.3 INSPECTION
48 - 4.3.1 General
51 - 4.3.2 Types of inspection
52 - 4.3.3 Grades of inspection
52 - 4.4 ITEMS REQUIRING INSPECTION
52 - 4.5 TESTING
52 - 4.5.1 General
52 - 4.5.2 Pre-commissioning tests
53 - SECTION 5 MAINTENANCE
53 - 5.1 SCOPE OF SECTION
53 - 5.2 REMEDIAL MEASURES AND MODIFICATIONS TO EQUIPMENT
53 - 5.3 MAINTENANCE OF FLEXIBLE CABLES
53 - 5.4 WITHDRAWAL FROM SERVICE
53 - 5.5 FASTENINGS AND TOOLS
53 - 5.6 ENVIRONMENTAL CONDITIONS
54 - 5.7 EARTHING AND EQUIPOTENTIAL BONDING
54 - 5.8 CONDITIONS OF USE
54 - 5.9 MOVABLE EQUIPMENT AND ITS CONNECTIONS
54 - 5.10 OVERHAUL AND REPAIR
55 - APPENDIX A - LIST OF ADDITIONAL STANDARDS RECOGNIZED BY REGULATORYAUTHORITIES IN NEW ZEALAND
56 - APPENDIX B - EUROPEAN CERTIFICATION BODIES WHO CAN ISSUE ELECTRICAL SAFETY CERTIFICATION ON ELECTRICAL EQUIPMENT FOR USE...
59 - APPENDIX C - FRICTIONAL SPARKING RISKS WITH LIGHT METALS*AND THEIR ALLOYS
59 - C1 GENERAL
59 - C2 RIGIDLY MOUNTED EQUIPMENT
59 - C3 PORTABLE AND TRANSPORTABLE EQUIPMENT
59 - C4 FANS
59 - C5 ALUMINIUM CONDUCTORS
61 - APPENDIX D - LIST OF REFERENCED DOCUMENTS
65 - APPENDIX E - ENCLOSURES WITH INTERNAL SOURCES OF RELEASE
65 - E1 GENERAL
65 - E2 TYPE AND EXTENT OF INTERNAL RELEASE
66 - E3 COMBINATION OF TYPES OF RELEASE
66 - E3.1 General
67 - E4 EFFECT OF THE COMBINATIONS OF TYPES OF RELEASE ON AREA CLASSIFICATION
68 - E5 PROTECTION FOR ENCLOSURES CONTAINING A SOURCE OF RELEASE
68 - E5.1 Types of enclosure
68 - E5.2 Flameproof enclosure
68 - E5.3 Pressurized and continuously diluted enclosures
68 - E5.4 Other enclosures
68 - E6 SELECTION OF A TYPE OF EXPLOSION-PROTECTION
68 - E6.1 For enclosures containing a source of release
69 - E6.2 Using Table E1
71 - APPENDIX F - RELATIONSHIP BETWEEN EQUIPMENT GROUPS AND FORMERGAS GROUPS OR CLASSES
72 - APPENDIX G - REPORT ON THE DANGER FROM HIGH-INTENSITY LIGHT SOURCES INHAZARDOUS ATMOSPHERES
72 - G1 INTRODUCTION
72 - G2 BREADTH OF EXPERIMENTAL INVESTIGATIONS
73 - G3 REFERENCE EXPERIMENTS
73 - G4 CORRELATION WITH KNOWN IGNITION PARAMETERS
75 - G5 PREDICTIVE COMPUTATIONS
75 - G6 LIMITING SAFETY CRITERIA AND COMPARISON WITH EXPERIMENTAL RESULTS
76 - G7 CONCLUSIONS
80 - APPENDIX H - THE NATIONAL CERTIFICATION SCHEMESFOR EXPLOSION-PROTECTED ELECTRICAL EQUIPMENT(TERMED Ex EQUIPMENT)
80 - H1 INTRODUCTION
80 - H2 AUS Ex SCHEME
82 - H3 ANZEx SCHEME
82 - H3.1 Background
83 - H3.2 Outline of ANZEx Scheme
84 - APPENDIX I - PROPERTIES OF FLAMMABLE LIQUIDS, VAPOURS AND GASES
84 - I1 SCOPE
84 - I2 FLASHPOINT
84 - I2.1 General
84 - I2.2 Materials having high flashpoints
84 - I2.3 Classification of flashpoints
85 - I3 IGNITION TEMPERATURE
85 - I3.1 General
85 - I3.2 Use of ignition temperature
85 - I4 EXPLOSIVE (FLAMMABLE) LIMITS
85 - I5 EXPLOSIVE (FLAMMABILITY) RANGE
85 - I6 VAPOUR DENSITY
85 - I6.1 General
86 - I6.2 Effects of temperature changes
86 - I7 BOILING POINT
86 - I8 TEMPERATURE CLASSIFICATION
86 - I9 CLASSIFICATION OF GASES AND VAPOURS
86 - I9.1 General
87 - I9.2 Classification according to the Maximum Experimental Safe Gaps (MESG)
87 - I9.3 Classification according to the Minimum Igniting Currents (MIC)
87 - I9.4 Classification according to MESG and MIC
87 - I9.5 Classification according to a similarity of chemical structure
88 - I10 GENERAL CONSIDERATIONS
88 - I10.1 Relation between ignition temperature and maximum surface temperature
88 - I10.2 Mixtures of compounds
89 - I10.3 Mists
89 - I10.4 Impurities
89 - I10.5 Effect of environments having other than normal atmospheric conditions
90 - APPENDIX J - CALCULATION OF THE EXPLOSIVE LIMITS FOR A MIXTURE OF GASES
90 - J1 LIMITS FOR SIMPLE MIXTURES
91 - J2 LIMITS FOR COMPLEX INDUSTRIAL GAS MIXTURES

Specifies general requirements for the selection, installation and maintenance of electrical equipment for use in areas where 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 equipments 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.

First published as AS 1076.1-1977.
Revised and redesignated as AS 2381.1-1991.
Jointly revised and redesignated as AS/NZS 2381.1:1999.