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AS/NZS IEC 60079.10.1:2022 Sup 1:2022


Explosive atmospheres — Classification of areas — Explosive gas atmospheres — Commentary (Supplement 1 to AS/NZS IEC 60079.10.1:2022)

AS/NZS IEC 60079.10.1:2022 Sup 1:2022 provides commentary and additional information to support the application of AS/NZS IEC 60079.10.1:2022.
Published: 24/06/2022
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Table of contents
Cited references
Content history
Table of contents
About this publication
1 Scope and general
1.1 Scope
1.2 Application
1.3 Normative references
1.4 Terms and definitions
2 Commentary
C1 Scope
C2 Normative references
C3 Terms and definitions
C3.6.1 Flammable substance
C3.6.2 Flammable liquid
C3.6.3 Liquefied flammable gas
C3.6.8 Flash point
C3.6.11 Auto-ignition temperature
C3.7.1 Normal operation
C3.7.3 Rare malfunction
C4 General
C4.1 Safety principles
C4.2 Hazardous area classification objectives
C4.3 Interior of equipment containing flammable materials
C4.4 Explosion risk assessment
C4.5 Catastrophic failures
C4.6 Competence of personnel
C5 Hazardous area classification methodology
C5.1 General
C5.2 Classification by sources of release method
C5.3 Use of industry codes and national standards
C5.4 Simplified methods
C5.5 Combination of methods
C6 Release of flammable substance
C6.1 General
C6.2 Sources of release
C6.3 Forms of release
C7 Ventilation (or air movement) and dilution
C7.1 General
C7.2 Main types of ventilation
C7.2.1 General
C7.2.2 Natural ventilation
C7.2.3 Artificial ventilation
C7.2.4 Degree of dilution
C8 Type of zone
C9 Extent of zone
C10 Documentation
C10.1 General
C10.2 Drawings, data sheets and tables
Annex CA
Annex CB
CB.1 Symbols
CB.2 Examples of grade of release
CB.3 Assessment of grades of release
CB.4 Summation of releases
CB.5 Hole size and source radius
CB.6 Forms of release
CB.7 Release rate
CB.7.1 General
CB.7.2 Estimation of release rate
CB.7.2.1 General
CB.7.2.2 Release rate of liquids
CB.7.2.3 Release rate of gas or vapour
CB.7.3 Release rate from evaporative pools
CB.8 Release from openings in buildings
Annex CC
CC.1 Symbols
CC.2 General
CC.3 Assessment of ventilation and dilution and its influence on hazardous area
CC.4 Examples of ventilation arrangements and assessments
CC.4.1 Introduction
CC.4.2 Jet release in a large building
CC.4.3 Jet release in a small naturally ventilated building
CC.4.4 Jet release in a small artificially ventilated building
CC.4.5 Release with low velocity
CC.4.6 Fugitive emissions
CC.4.7 Local ventilation-extraction
CC.5 Natural ventilation in buildings
Annex CD
Annex CE
Annex CF
Annex CG
Annex CH
Annex CI
Annex CJ
Annex CK
CK.1 General
Appendix A
A.1 General
A.2 Liquid flash point
A.3 Common situations
A.3.1 General
A.3.2 Ventilation and dispersion — Mechanical ventilation exhaust and inlet ducts associated with an enclosed structure classified as hazardous (see Figure A.3.2)
A.3.3 Underground wiring enclosures
A.3.4 Contaminated water and waste water facilities
A.3.4.1 General
A.3.4.2 Pumps
A.3.4.3 Coalescing plate separator units in locations providing a medium degree of dilution (see Figure A.3.4.3)
A.3.4.4 Waste liquids collection and drainage facilities
Appendix B
B.1 Vehicle workshops
B.2 Vehicle parking and standing areas
B.3 Petrol, ethanol, LPG and CNG dispensing
B.3.1 General
B.3.2 Interior of petrol and ethanol dispensing units outdoors (see Figure B.3.2)
B.3.3 Exterior of petrol and ethanol dispensing units outdoors [see Figure B.3.3(A)]
B.3.4 Exterior of petrol and ethanol dispensing units mounted on a wharf/jetty outdoors [see Figure B.3.4]
B.3.5 Petrol and ethanol dispensing units indoors (see Figure B.3.5)
B.3.6 Interior of LPG dispensing units outdoors (see Figure B.3.6)
B.3.7 Exterior of LPG dispensing units outdoors (see Figure B.3.7)
B.3.8 Exterior of LPG dispensing units mounted on a wharf/jetty outdoors (see Figure B.3.8)
B.3.9 Other LPG dispensing units outdoors (see Figure B.3.9)
B.3.10 CNG dispensing units outdoors (see Figure B.3.10)
B.3.11 CNG dispensing units outdoors — Public stations (see Figure B.3.11)
B.3.12 Specific dispensing areas located at dispensing stations
B.4 Aircraft hangars and refuelling areas
B.4.1 Aircraft hangars
B.4.2 Aircraft in hangars — Kerosene type fuels
B.4.3 Petrol, Avgas and JP4 and wide cut type fuels
B.4.4 Pits or depressions
B.4.5 Other hangar areas
B.4.6 Aircraft refuelling at airport tarmac and ramp areas — All fuels
Appendix C
C.1 General
C.2 Explosive atmospheres from water miscible solvents
C.3 Flammable liquid tanks
C.3.1 Floating roof tanks and tanks containing internal floating pans — GHS Category 1 or 2 liquids (see Figure C.3.1)
C.3.2 Floating roof tanks and tanks containing internal floating pans — GHS Category 3 liquids
C.3.3 Vertical and horizontal fixed roof free vented tanks — GHS Category 1 or 2 liquids (see Figure C.3.3)
C.3.4 Vertical and horizontal fixed roof free vented tanks — GHS Category 3 liquids
C.3.5 Tank at nominally atmospheric pressure outdoors and with pressure/vacuum relief systems — GHS Category 1 or 2 liquids (see Figure C.3.5)
C.3.6 Tank at nominally atmospheric pressure outdoors and with pressure/vacuum relief systems — GHS Category 3 liquids
C.3.7 Sealed tank or cryogenic (refrigerated) tank
C.3.8 Above ground vaulted or double skinned tanks [see Figure C.3.8(A)]
C.3.9 Underground storage tanks
C.4 Package storage including drum or pail storage for GHS Category 1, 2, or 3 liquids
C.4.1 General
C.4.2 Stores for large containers
C.4.3 Stores for small containers
C.5 Package filling processes
C.6 Pumps for flammable liquid transfer
C.7 Road or rail tanker loading and discharge
C.7.1 General
C.7.2 Loading for GHS Category 1 or 2 liquids
C.7.3 Loading for GHS Category 3 liquids
C.7.4 Road or rail tanker, discharge with or without vapour recovery (see Figure C.7.4)
C.7.5 Hoses used for loading and discharge
C.8 Garages and workshops for tanker vehicles
C.9 Valves and fittings in liquid piping systems
C.10 Pits and trenches
Appendix D
D.1 Surface coatings and adhesives
D.1.1 General
D.1.2 Manufactured products
D.1.2.1 General
D.1.2.2 Package storage
D.1.2.3 Bulk storage
D.1.2.4 Tinting areas
D.1.2.5 Package filling process
D.1.2.6 Loading and unloading packages areas
D.2 Spray painting
D.2.1 General
D.2.2 Enclosed type batch spray painting booths
D.2.3 Special spray booth applications
D.2.4 Open-fronted booths conforming to AS/NZS 4114
D.2.5 Open-fronted booths not conforming to AS/NZS 4114
D.2.6 Tunnel or production booth
D.2.7 Painting — Other areas
D.2.7.1 General
D.2.7.2 Paint spraying and dipping
D.2.7.3 Drying and baking areas
D.2.7.4 Motor body workshops
D.2.7.5 Adjacent areas
D.2.8 Powder coating
D.2.9 Continuous coating facilities
D.3 Reinforced plastics
D.3.1 General
D.3.2 Classification of hazardous areas
D.3.2.1 Moulding
D.3.2.2 Curing
D.4 Batch-type processes
D.4.1 General
D.4.2 Small vessels
D.4.2.1 General
D.4.2.2 Open vessel, up to 20 L (see Figure D.4.2.2)
D.4.2.3 Closed vessel with tight fitting lid during operation (see Figure D.4.2.3)
D.4.3 Vessel containing flammable liquid, up to 5 000 L
D.4.3.1 General
D.4.3.2 Open vessel (see Figure D.4.3.2)
D.4.3.3 Closed vessel during operation with tight fitting lid (see Figure D.4.3.3)
D.4.3.4 Dry-cleaning equipment (see Figure D.4.3.4)
D.4.3.5 Solvent extraction (see Figure D.4.3.5)
D.4.3.6 Solvent recovery by distillation (see Figure D.4.3.6)
D.5 Printing presses employing solvent-based inks
D.5.1 General
D.5.2 Example classifications of hazardous areas
Appendix E
E.1 Gas industry codes
E.1.1 General
E.1.2 Consumer installations
E.1.3 Gas distribution
E.1.3.1 General
E.1.3.2 Consumer meter assemblies
E.1.3.3 Pressure relief discharge points
E.1.3.4 Pit containing network pressure control equipment
E.1.3.5 Above ground network pressure control station (kiosk)
E.1.4 LPG Storage and handling installations
E.1.4.1 General
E.1.4.2 Pressure storage tanks other than buried or mounded tanks
E.1.4.3 Tank filling or discharge connections
E.1.4.4 Gauging devices on a tank
E. Ullage gauges (including roto-gauges, try cocks and slip tubes)
E. Variable contents gauges (float type with magnetic drive)
E.1.4.5 Tank safety relief valves
E.1.4.6 Hydrostatic relief valves
E.1.4.7 First stage regulator supplied from tank or cylinder
E.1.4.8 Valve, flange or threaded pipe connection
E.1.4.9 Pumps
E.1.4.10 Compressors in locations with adequate dispersion
E.1.4.11 Vaporizers
E.1.4.12 Bleed vents or hose venting points in liquid piping system
E.1.4.13 Pits where explosive atmospheres can accumulate
E.1.4.14 Cylinder filling (other than in situ)
E.1.4.15 Cylinders, whether in storage or installed for use, exchange type in locations that provide medium dilution
E.1.4.16 Cylinders, whether in storage or installed for use outdoors, in situ fill type (with limited gas bleeding for contents checking)
E.1.4.17 Cylinder storage structure that does not provide at least medium dilution
E.1.5 LNG, CNG and hydrogen installations
E.1.5.1 General
E.1.5.2 Pressure storage tank
E.1.5.3 Cryogenic tank filling or discharge connections
E.1.5.4 Gauging devices on tank
E.1.5.5 Variable contents gauges
E.1.5.6 Tank safety relief valves and manual tank vents
E.1.5.7 Hydrostatic relief valves
E.1.5.8 Valve, flange or threaded connection
E.1.5.9 Cryogenic pumps
E.1.5.10 Gas compressors in locations that provide medium dilution
E.1.5.11 Vaporizers
E.1.5.12 Pits where explosive atmospheres may accumulate
E.1.5.13 Hydrogen storage
E.1.5.14 Natural gas cylinders
E.1.5.15 High pressure cylinder filling compressors
E.1.5.16 Natural gas cylinder filling hoses
E.1.5.17 Production and cylinder applications for neutrally buoyant
E.1.5.18 Hydrogen cylinders
E.1.6 Petroleum production and processing and transmission pipelines
E.1.6.1 General
E.1.6.2 Pits
E.1.6.3 Closures on pig receivers, launchers and filter separator vessels, outdoors or in open shelter
E.1.6.4 Limited quantity vents (e.g. instrument vents), outdoors or in open shelters
E.1.6.5 Gas equipment outdoors or in open shelters
E.1.6.6 Gas equipment not in an open shelter
E.2 Biogases or biomethane
E.2.1 General
E.2.2 Landfill gas, farm waste, sewage treatment and sewage pumping plants
E.2.2.1 General
E.2.2.2 Floating roof digestion tanks
E.2.2.3 Covered digestion tanks
E.2.3 Pipe galleries
E.2.4 Enclosed areas through which sludge is conveyed
E.2.5 Sludge dewatering processes
E.2.6 Sewage pumping plants
Appendix F
F.1 Fume cupboards and laboratories
F.1.1 General
F.1.2 Laboratories
F.1.3 Fume cupboards not conforming to AS/NZS 2243.8 or AS/NZS 2243.9 (see Figure F.1.3)
F.2 Fruit ripening rooms
F.2.1 General
F.2.2 Classification of hazardous areas
F.3 Ammonia systems
F.3.1 General
F.3.2 Anhydrous ammonia in outdoor locations
F.3.2.1 General
F.3.2.2 Storage vessels
F. Internal volume
F. External area
F. Piping including valves, flanges
F. Filling or unloading points and the discharge point of relief valves
F.3.2.3 Pumps and compressors
F.3.2.4 Vaporizers
F.3.3 Anhydrous ammonia in indoor locations
F.3.4 Aqueous ammonia systems
F.3.4.1 General
F.3.4.2 Closed containers
F.3.4.3 Areas providing a high degree of dilution
F.3.4.4 Areas not providing a high degree of dilution
Appendix G
G.1 Scope
G.2 Refineries and major processing plants — Heavier-than-air gases and vapours
G.2.1 General
G.2.2 Classification of hazardous areas
G.2.2.1 Extent of hazardous areas
G.2.2.2 Open air situations
G.2.2.3 Enclosed structures and surrounding areas
G.2.2.4 Open structures and surrounding areas
G.2.2.5 Enclosed structures with plenum of safe atmosphere
G.2.3 Refineries and major processing plants — Lighter-than-air gases and vapours
G.2.3.1 General
G.2.3.2 Classification of hazardous areas
G. In closed systems within refinery process areas — Outdoors
G. Compressor structures providing a medium degree of dilution
G. In closed systems within refinery process areas with a low degree of dilution
G. Compressor structure providing a low degree of dilution
G.2.4 Use of local extraction systems
Appendix H
H.1 General
H.2 Design of dilution systems
H.3 Rate of dilution air flow
H.3.1 General
H.3.2 Calculated rate of dilution air flow
H.3.3 Amount of vapour produced per litre of solvent evaporated (V m3/L)
H.3.4 Amount of air required to reduce 1 m3 of solvent vapour to LFL (A, m3/m3)
H.3.5 Estimation of VA
H.3.6 LFL correction factor C
H.3.7 Maximum instantaneous evaporation rate of liquid solvent (Q, L/min)
H.3.8 Temperature/volume correction
H.3.9 Measurement of quantity of air exhausted from a room or enclosure
H.4 Design of extraction systems
H.4.1 Elements of extraction systems
H.4.2 Hoods or enclosure
H.4.3 Capture velocities and air volume exhausted
H.4.4 Exterior hoods
H.4.5 Special extraction requirements
H.5 Exhaust of hot processes
H.5.1 Estimation of exhaust capacity
H.5.2 Use of low and high canopy hoods
H.5.3 Design equations
Appendix I
I.1 Introduction
I.2 Hazardous area classification and EPLs
I.3 Risk-based EPL assessments
I.4 Other than risk-based EPL assessments
I.5 Relationships of EPLs to other acts and regulations
Cited references in this standard
Content history
DR AS/NZS 60079.10.1 Supp 1: 2019