hazardous area classification
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�○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ about us
Govan Industries Pty Ltd. is a privately owned Electrical EngineeringGovan Industries Pty Ltd. is a privately owned Electrical EngineeringGovan Industries Pty Ltd. is a privately owned Electrical EngineeringGovan Industries Pty Ltd. is a privately owned Electrical EngineeringGovan Industries Pty Ltd. is a privately owned Electrical Engineering
Company based in MelbourCompany based in MelbourCompany based in MelbourCompany based in MelbourCompany based in Melbourne, Australia. For over 40 years, Govanne, Australia. For over 40 years, Govanne, Australia. For over 40 years, Govanne, Australia. For over 40 years, Govanne, Australia. For over 40 years, Govan
Industries have used most advanced technology to manufacturIndustries have used most advanced technology to manufacturIndustries have used most advanced technology to manufacturIndustries have used most advanced technology to manufacturIndustries have used most advanced technology to manufacture explosione explosione explosione explosione explosion
prprprprprotection electrical equipment for installation in hazarotection electrical equipment for installation in hazarotection electrical equipment for installation in hazarotection electrical equipment for installation in hazarotection electrical equipment for installation in hazardous ardous ardous ardous ardous areas.eas.eas.eas.eas.
The ResearThe ResearThe ResearThe ResearThe Research and Development team at Govan uses computer aidedch and Development team at Govan uses computer aidedch and Development team at Govan uses computer aidedch and Development team at Govan uses computer aidedch and Development team at Govan uses computer aided
drafting techniques to prdrafting techniques to prdrafting techniques to prdrafting techniques to prdrafting techniques to produce a full range of Flameproduce a full range of Flameproduce a full range of Flameproduce a full range of Flameproduce a full range of Flameproof (Exd), Incroof (Exd), Incroof (Exd), Incroof (Exd), Incroof (Exd), Increasedeasedeasedeasedeased
safety (Exe), Dust excluding ignition prsafety (Exe), Dust excluding ignition prsafety (Exe), Dust excluding ignition prsafety (Exe), Dust excluding ignition prsafety (Exe), Dust excluding ignition proof (DIP) and Proof (DIP) and Proof (DIP) and Proof (DIP) and Proof (DIP) and Pressurised (Exp)essurised (Exp)essurised (Exp)essurised (Exp)essurised (Exp)
electrical equipments.electrical equipments.electrical equipments.electrical equipments.electrical equipments.
TTTTTo ensuro ensuro ensuro ensuro ensure high quality pre high quality pre high quality pre high quality pre high quality products, Govan has adopted a quality assuranceoducts, Govan has adopted a quality assuranceoducts, Govan has adopted a quality assuranceoducts, Govan has adopted a quality assuranceoducts, Govan has adopted a quality assurance
system to AS 3901 (ISO 9001). All prsystem to AS 3901 (ISO 9001). All prsystem to AS 3901 (ISO 9001). All prsystem to AS 3901 (ISO 9001). All prsystem to AS 3901 (ISO 9001). All products aroducts aroducts aroducts aroducts are tested by thee tested by thee tested by thee tested by thee tested by the
interinterinterinterinternationally rnationally rnationally rnationally rnationally recognised testing stations, to those standarecognised testing stations, to those standarecognised testing stations, to those standarecognised testing stations, to those standarecognised testing stations, to those standards specified byds specified byds specified byds specified byds specified by
StandarStandarStandarStandarStandards Association of Australia. The Australian standards Association of Australia. The Australian standards Association of Australia. The Australian standards Association of Australia. The Australian standards Association of Australia. The Australian standards ards ards ards ards are closelye closelye closelye closelye closely
aligned to those praligned to those praligned to those praligned to those praligned to those produced by the IEC (Interoduced by the IEC (Interoduced by the IEC (Interoduced by the IEC (Interoduced by the IEC (International Electrnational Electrnational Electrnational Electrnational Electrotechnicalotechnicalotechnicalotechnicalotechnical
Commission) and arCommission) and arCommission) and arCommission) and arCommission) and are similar to American standare similar to American standare similar to American standare similar to American standare similar to American standards.ds.ds.ds.ds.
Govan prGovan prGovan prGovan prGovan products aroducts aroducts aroducts aroducts are used by all major oil companies in Australia and are used by all major oil companies in Australia and are used by all major oil companies in Australia and are used by all major oil companies in Australia and are used by all major oil companies in Australia and areeeee
exported to over 20 countries in the Asia-pacific and Middle East rexported to over 20 countries in the Asia-pacific and Middle East rexported to over 20 countries in the Asia-pacific and Middle East rexported to over 20 countries in the Asia-pacific and Middle East rexported to over 20 countries in the Asia-pacific and Middle East regions.egions.egions.egions.egions.
Govan has a successful heritage in prGovan has a successful heritage in prGovan has a successful heritage in prGovan has a successful heritage in prGovan has a successful heritage in providing state-of-the-art qualityoviding state-of-the-art qualityoviding state-of-the-art qualityoviding state-of-the-art qualityoviding state-of-the-art quality
prprprprproducts and services to its clients. Govan’oducts and services to its clients. Govan’oducts and services to its clients. Govan’oducts and services to its clients. Govan’oducts and services to its clients. Govan’s key objective is to imprs key objective is to imprs key objective is to imprs key objective is to imprs key objective is to improveoveoveoveove
prprprprproducts and products and products and products and products and processes throcesses throcesses throcesses throcesses through an ongoing commitment to rough an ongoing commitment to rough an ongoing commitment to rough an ongoing commitment to rough an ongoing commitment to researesearesearesearesearch andch andch andch andch and
development. This has made Govan a successful and rdevelopment. This has made Govan a successful and rdevelopment. This has made Govan a successful and rdevelopment. This has made Govan a successful and rdevelopment. This has made Govan a successful and reputed globaleputed globaleputed globaleputed globaleputed global
technology organisation.technology organisation.technology organisation.technology organisation.technology organisation.
HAZARDOUS AREA EQUIPMENT
A hazardous area is defined as an area in which an explosive atmosphere is present, or may beexpected to be present, in quantities such as to require special precautions for the construction,installation and use of potential ignition sources.
Major industries affected would include oil, gas, petroleum refineries, chemical plants, seweragetreatment and grain handling. Other industries include spray painting shops, aircraft hangars, petroldepots, terminals and garages.
Therefore the use of any electrical apparatus in these areas is strictly controlled through variousprotection techniques to enable the operators to facilitate the handling or processing of thehazardous materials. This removes the possibility of ignition being caused by the electrical apparatuscontained within the hazardous area.
Standards Australia prepares, publishes and maintains Australian Standards and in the case ofhazardous areas, looks at all aspects of implementing standards that affect the certification, testing,installation and maintenance of electrical equipment in these areas.
Note: Australian Standards has endorsed the adoption of the IEC 60079 gases andvapours and IEC 61241 dust series of standards as joint Australian / New ZealandStandards. In the new series of standards there is no reference to Class I and Class IIareas. The different zones are identified as zones 0, 1 and 2 for explosive gasatmospheres and zones 20, 21 and 22 for explosive dust atmospheres.
Hazardous areas andhazardous area equipment
Conditions required for an explosion
An explosion will only occur when three basic conditions are present:
� Explosive material
� Oxygen / air
� Sources of ignition
Remove any one of these basic conditions and an explosion willnot occur.
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EXPLOSION To produce an explosion, three elements are required.
OXYGENIN
THE
AIR
A RISE IN TEMPERATURE, SPARK, ETC.
INFLA
MM
ABLE
SUBSTANCES(GAS,LIQUID,DUST)
HAZARDOUS AREA EQUIPMENT
Explosive gas atmospheres AS 2430.1
Combustible dusts AS/NZS 61241.3 (AS 2430.2)
Specific occupancies AS 2430.3
GROUP IIGROUP IIGROUP IIGROUP IIGROUP II Flammable gas, vapour or mist Combustible dusts
Classification of hazardous areas
Zone classification
Zone 0Zone 0Zone 0Zone 0Zone 0 Continuously hazardous (protection technique allowed)ExiaExiaExiaExiaExia intrinsic safety
Zone 1Zone 1Zone 1Zone 1Zone 1 Frequently hazardous (protection technique allowed)ExibExibExibExibExib intrinsic safetyExdExdExdExdExd flameproofExeExeExeExeExe increased safetyExpExpExpExpExp pressured or purgedExv Exv Exv Exv Exv ventilationExsExsExsExsExs special protection
Zone 2Zone 2Zone 2Zone 2Zone 2 Infrequently hazardous (protection technique allowed)ExnExnExnExnExn Non-sparking
GrGrGrGrGroup IIoup IIoup IIoup IIoup II Classification (protection technique allowed)DIP dust - excluding ignition proof:- the new DIP standardwill reflect 3 zones for dust areas, zone 20, 21 and 22.
Group II hazardous area zones
Gas / VGas / VGas / VGas / VGas / Vapour arapour arapour arapour arapour area zonesea zonesea zonesea zonesea zones
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Dust arDust arDust arDust arDust area zonesea zonesea zonesea zonesea zones
Zone 0 Zone 0
Zone 1
Zone 2
Zone 0
Zone 1
Zone 21
Zone 20
Zone 22
Zone 1
The classification of ZONE is a complex prThe classification of ZONE is a complex prThe classification of ZONE is a complex prThe classification of ZONE is a complex prThe classification of ZONE is a complex problem but the main factors to consider aroblem but the main factors to consider aroblem but the main factors to consider aroblem but the main factors to consider aroblem but the main factors to consider are:e:e:e:e:
• The probability of the presence of gas
• The quantity and duration of hazardous vapour
• The amount of ventilation
• The nature of gas: lighter or heavier than air
HAZARDOUS AREA EQUIPMENT
Group classification
Hazardous area equipment is specified in terms of the types of gases present, being:
GrGrGrGrGroup Ioup Ioup Ioup Ioup I For mining applications
GrGrGrGrGroup IIoup IIoup IIoup IIoup II For general industry
Equipment must be categorised as being suitable for use with gases in Group II industries.
GrGrGrGrGroup Ioup Ioup Ioup Ioup I equipment has a representative gas of Methane and all equipment used in undergroundmining applications fall into this category. Any other equipment will be GrGrGrGrGroup IIoup IIoup IIoup IIoup II classified.
As shown in the table below, GrGrGrGrGroup IIoup IIoup IIoup IIoup II is again segmented into three different representative gasgroups, Propane, Ethylene and Hydrogen. GrGrGrGrGroups IIA, IIBoups IIA, IIBoups IIA, IIBoups IIA, IIBoups IIA, IIB and IICIICIICIICIIC respectively.
The consequence of an explosion:The consequence of an explosion:The consequence of an explosion:The consequence of an explosion:The consequence of an explosion:
The division of plant or parts of plant into zones is generally undertaken by the supervisory authorityin that industry in tandem with process engineers / chemists at the design and or construction stage.
GroupClassification Representative Gas
IIIII Methane
IIAIIAIIAIIAIIA Propane
IIBIIBIIBIIBIIB Ethylene
IICIICIICIICIIC Hydrogen
As stated these are only representative gases where in fact there are many different types of gasesone can be presented with when classifying equipment.
Temperature classificationTTTTTemperaturemperaturemperaturemperaturemperature Classe Classe Classe Classe Class T1T1T1T1T1 T2T2T2T2T2 T3T3T3T3T3 T4T4T4T4T4 T5T5T5T5T5 T6T6T6T6T6
Maximum surfacetemperature (°C) < 450 < 300 < 200 < 135 < 100 < 85
Minimum ignitiontemperature of gas (°C) > 450 > 300 > 200 > 135 > 100 > 85
Minimum ignitiontemperature of dust (°C) > 500 > 350 > 250 > 185 > 150 > 135
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HAZARDOUS AREA EQUIPMENT
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A “protection technique” is a specific process which negates one of the three components ofcombustion.
Zone protection techniques
Group II
ApplicableApplicableApplicableApplicableApplicable PrPrPrPrProtectionotectionotectionotectionotection Relevant standar Relevant standar Relevant standar Relevant standar Relevant standardddddzonezonezonezonezone techniquetechniquetechniquetechniquetechnique EquipmentEquipmentEquipmentEquipmentEquipment InstallationInstallationInstallationInstallationInstallation DescriptionDescriptionDescriptionDescriptionDescriptionZones 1 & 2 Exd AS 2380.2 AS 2381.2 Flameproof Enc.Zones 1 & 2 Exe AS 2380.6 AS 2381.6 Increased safetyZones 0 - ia Exi AS 2380.7 AS 2381.7 Intrinsic safety
1 - ib2 - ib
Zones 1 & 2 Exm AS 2431 - EncapsulatedZones 2 Exn AS 2380.9 AS 1076.7 app.Zones 1 & 2 Exo IEC 79-6 - Non-sparkingZones 1 & 2 Exp AS 2380.4 AS 2380.4 Oil immersion
PressurisedZones 1 & 2 Exq IEC 79-6 - rooms & encl.Zones 0,1 & 2 Exs AS 1826 AS 1076.8 Sand filledZones 1 & 2 Exv AS 1482 - Special protection
VentilationZones 20,21 & 22 DIP AS/NZS AS/NZSZones 20,21 & 22 Exi 61241.3 61241.3 AS Dust ignition proofZones 20,21 & 22 Exm AS 2380.7 2381.7 - Intrinsic safetyZones 20,21 & 22 Exp AS 2431 AS 2380.4 Encapsulation
AS 2380.4 Pressurised
Temperature classification takes into account the ignition temperature of the flammable gasespresent in the particular environment.
Ambient temperatures are of course considered in this appraisal, however circumstances which mayincrease this surface temperature must also be taken into account.
For example, an enclosure shall over a period of time, collect a layer of dust on its surfaces. This shallincrease the units overall operating and surface temperatures, to a point where if it rises to a pointnearing the flash or combustion point of surrounding gases, liquids or dusts, then an explosivesituation would occur.
For Group I classified electrical equipment, where coal dust can form a layer, the maximum surfacetemperature shall not exceed 150 °C. If this layer can be avoided through sealing or protection fromthe ingress of dust, the internal surfaces must not exceed 450 °C. In respect to Group II electricalequipment, temperatures are classified as per the following table.
Temperature classes T1 to T6 (AS 1280.1) are used for all protection techniques, and correspond tothe electrical devices maximum operational temperature.
The better the equipment, the lower the rated surface temperature. In other words a rating of T4 isbetter than that of T2.
Therefore, those items certified as being T6, can be used in T1, T2, T3, T4, T5 and T6 gases. Whereasa T2 certification only allows a piece of equipment to be used in T1 and T2 gases.
HAZARDOUS AREA EQUIPMENT
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The Australian standards are based on International Electrotechnical Commision (IEC) standards andare similar to Cenelec and British standards in respect of Zone classifications, Gas groups,Temperature ratings and Testing Methods. This is illustrated in the table below.
Zone protection techniques
II A Ammonia, Butane, Propane, Pentane, D Acetone, Propane
Benzine, Acetone, Hexane, Heptane, Ethane, Butane
Iso-octane,Decane, Cyclohexane, Methanol.
II B Butadiene, Ethylene Oxide, Town Gas, C Acetaldehyde
Coke-oven Gas. Ethylene
II C Hydrogen, Acetylene. B Hydrogen, Butadiene
Ethylene oxide
A Acetylene
Weather Proof IP 54 Nema 3
Water Tight IP 65 Nema 4
Dust Tight IP 66 Nema 4x
Immersion Proof IP 67 Nema 6
Explosion Proof Exd Nema 7
Dust Ignition Proof D.I.P. Nema 9
Exd 2380-2 79-1 EN50018 UL698
Exe 2380-6 79-7 EN50019 -
Exn 2380-9 79-15 EN50021 CSA22213
Exp 2380-4 79-2 EN50016 NPF496
Exi 2380-7 79-1 EN50020 ANS14913
Gas Groups andRepresentativeGasses
ApplicableStandardsFor VariousExplosionProtectionTechniques
ITEMSITEMSITEMSITEMSITEMS AUSTRALIAAUSTRALIAAUSTRALIAAUSTRALIAAUSTRALIA IECIECIECIECIEC CENELECCENELECCENELECCENELECCENELEC USAUSAUSAUSAUSA
Class “1” ZONE ZONE 0 ZONE 0 ZONE 0 DIVISION 1
Classification ZONE 1 ZONE 1 ZONE 1
ZONE 2 ZONE 2 ZONE 2 DIVISION 2
Temperature Rating(Limit of Temp. RiseOver Ambient Of40oC)
DEGREES OF PROTECTION
Max Ignition Temp (oC)
T1 T2 T3 T4 T5 T6
450 300 200 135 100 85
Max Ignition Temp (oC)
T1 T2 T2A T2B T2C T2D T3
450 300 280 260 230 215 200
T3A T3B T3C T4 T4A T5 T6
180 165 160 135 120 100 85
Note: Note: Note: Note: Note: The information in this catalogue is subject to change and should always be verified against thecurrent Australian Standard.
HAZARDOUS AREA EQUIPMENT
Method Symbol Type of protection
Exclusion DIP Dust-excluding ignition proofExm EncapsulationExn Non-sparking (hermetically sealed devices, sealed
devices and restricted breathing)Exp Pressurised enclosure / RoomsExq Sand-filled (powder filling)
Explosion containment Exd Flameproof enclosure
Energy limitation Exi Intrinsic safety
Dilution Exv Ventilation
Avoidance of ignition Exe Increased safetysource Exn Non-sparking (inherently non-sparking)
Explosion protection techniques
Ex protection techniques
0-6
Power Apparatus, Switchgears, Motors (all devices able to ignite flammable mixtures in normal operations)
Capacitors, Electronics
Power Apparatus (requires special measures to maintain safety features)
Transformers
Measuring and Control Systems (avoiding hot spots on printed boards)
Terminal and Connection boxes, Squirrel cage Motors and Lightning (no incendiary or hot surfaces in normal operations)
Terminal and Connection Boxes, Data Processing (small electrical values)
Powder Filling
Pressurised Apparatus
Oil Immersion
Encapsulation
Increased Safety
Intrinsic Safety
Flame proof Enclosure
Type of Protection Typical ApplicationSymbol
d
P
q
o
e
m
i
Principle
INGRESS PROTECTION (IP)RATINGS TO AS 1939 (IEC 529)
Degree of protection of the enclosures for electrical equipment in accordance with the IEC 529 andEN 60529 standards.
Note:Note:Note:Note:Note: 1 The explosion protection certification of the equipment alone does not necessarily mean ithas an adequate degree of protection for specified weather or environment. Hence it isnecessary to check the IP rating of the equipment before selection for a particularenvironment.
2 All GOVAN equipment is tested and certified for minimum IP 65 rating.0-7
Protected against solid bodies largerthan 50 mm (eg: accidental contact with the hand)
Protected againstsolid bodies larger than2.5 mm (tools,wires)
Protected against solid bodies largerthan 1 mm (fine tools, small wires
Protected against dust (no harmful deposit)
Completely protected against dust
Protected against solid bodies largerthan 12.5 mm (eg: finger of the hand)
2.5 mm
1 mm
Protected againstvertically-falling drops of water (condensation)
Protected againstdrops of water falling at up to 150
from the vertical
Protected against projections of water from all directions
Protected against jets of water from all directions
Completely protected against jets of water of similar force to heavy seas.
Protected against the effects of immersion
Protected againsteffects of prolonged immersion underspecific conditions
m
15 c
m
1 m
12.5 mm
50 mm
60 0
15 0
Protected againstdrops of rainwater at up to 600 from the vertical
0
1
2
3
4
5
6
1
2
3
4
5
6
0
Tests Tests
No Protection No Protection
7
8
PrPrPrPrProtection against solid bodiesotection against solid bodiesotection against solid bodiesotection against solid bodiesotection against solid bodies PrPrPrPrProtection against liquidsotection against liquidsotection against liquidsotection against liquidsotection against liquids
Adaptors 8
Break glass alarms 4
Beacons - rotating 1- flashing 1
Bells 4
Cable glands 8
Conduit fittings - weatherproof 8
Circuit breakers 6
Compound 8
Control stations 9
Pushbuttons 9
Pilot lights 9
Switch 9
Custom built control panels 6
Distribution boards 6
Dust ignition proof junction boxes (D.I.P.) 3
Increased safety junction boxes (Exe) 3
Elbows 8
Enclosures with windows 5, 6
Flameproof junction boxes (Exd) 3
Small round 3Rectangular 3Large 3Screwed cover 3
Float switch 4
Foot and palm switch 4
Fluorescent lights 1
Zone 1Zone 2 1
Flood lights 1
Zone 1Zone 2 1
High bay lights - High intensity discharge 1
Zone 1Zone 2 1
Incandescent lights 1
Instrument enclosures 5
Isolators 2
Description Section
QUICK REFERENCE GUIDE
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Junction boxes 3
Exd 3Exe & D.I.P. 3
Key switches 2
Lighting 1
Limit switches 4
Motor starters 6
DOL 6Star/Delta 6Reversing 6
Meter housing 5
Modules - components 2
Motor control centres 6
Nipples 8
Panelboards 6
Pilot lights 2
Plugs 7
Pressure switches 4
Pushbutton stations 2
Pressurised systems 5
Receptacles 7
Reducers 8
Switch racks / switchboards 6
Selector switches 2
Sealing fittings 8
Strobe lights 1
Sealing compounds 8
Stopping plugs 8
Sail switch 4
Security camera 4
Tank observation lights 1
Tees 8
Thermostats 4
Unions 8
Vessel lights 1, 4
Weatherproof conduit fittings 8
Description Section
QUICK REFERENCE GUIDE
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