HAZARDOUS AREA HAZARDOUS AREA CLASSIFICATIONS CLASSIFICATIONS HAZARDOUS AREA HAZARDOUS AREA CLASSIFICATIONS CLASSIFICATIONS 14 May 2003 14 May 2003 14 May 2003 14 May 2003 Feriansyah Feriansyah A Premier Oil Premier Oil Natuna Natuna Sea Ltd. Sea Ltd. Feriansyah Feriansyah A Premier Oil Premier Oil Natuna Natuna Sea Ltd. Sea Ltd. Premier Oil Premier Oil Natuna Natuna Sea Ltd. Sea Ltd. HSE Manager HSE Manager Premier Oil Premier Oil Natuna Natuna Sea Ltd. Sea Ltd. HSE Manager HSE Manager
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//HAZARDOUS/ CLASSIFIED AREAS HAZARDOUS/ CLASSIFIED AREAS DEFINITIONSDEFINITIONS
DEFINISI DAERAH BERBAHAYADEFINISI DAERAH BERBAHAYADEFINISI DAERAH BERBAHAYADEFINISI DAERAH BERBAHAYA
AA h llh ll bb d dd d tt bbAnAn areaarea shallshall bebe deemeddeemed toto bebe aahazardoushazardous area,area, wherewhere::HazardousHazardous areaarea isis anan areaarea inin whichwhichanan explosiveexplosive gasgas atmosphereatmosphere isisanan explosiveexplosive gasgas atmosphereatmosphere isispresent,present, oror likelylikely toto bebe presentpresent..
WHY DO WE NEED TO CLASSIFY AREASWHY DO WE NEED TO CLASSIFY AREAS??
H dH d AA Cl ifi tiCl ifi ti ii th dth d ff l il i ddHazardousHazardous AreaArea ClassificationClassification isis aa methodmethod ofof analyzinganalyzing andandclassifyingclassifying thethe environmentenvironment wherewhere explosiveexplosive gasgas atmospheresatmospheres maymayoccuroccur toto allowallow thethe properproper selectionselection ofof electricalelectrical apparatusapparatus toto bebeinstalledinstalled inin thatthat environmentenvironment..
1923 Hazardous locations first appear in the NEC
Background
• 1923 - Hazardous locations first appear in the NEC
• 1935 - Classes added to the concept
• 1947 - Divisions added
• RP 500 and NFPA 497 primary sources of guidance for Area Classification
• NEC provided guidance for equipment selection and installation methods
• API RP 505
Methods of Classifying Hazardous AreaMethods of Classifying Hazardous Area
• API 500 – American Petroleum Institute - using Divisions Method only for Petroleum Industries
• NEC, European Standards, API 505 - using Zoning Method for general industries including Petroleum: Class I is for Flammable/ Explosive/ gas Mixtures, Class II is for Combustible Dusts, Class III is for fibersis for fibers
• Oil & Gas Industries usually API RP500 to identify Hazardous• Oil & Gas Industries usually API- RP500 to identify Hazardous Area Classification on all of its installations
ClassClass II Flammable,Flammable, gases,gases, vaporsvapors ororli idli idClassClass II :: AA locationlocation whichwhich flammableflammable
gassesgasses oror vaporsvapors are,are, oror maymay bebepresentpresent inin thethe airair quantitiesquantitiessufficientsufficient toto produceproduce explosiveexplosive orori it bli it bl i ti t
CLASS I, DIVISION 1 CLASS I, DIVISION 1 -- API 500API 500
• Flammable gas or vapor concentration is likely to exist in the air under normal operating conditions
• Flammable atmospheric concentration is likely to occur frequently because of routine maintenance, or operations
• The area below the surrounding elevation or grade is such that flammable liquids or vapors may accumulate therein
CLASS I, DIVISION 1CLASS I, DIVISION 1 -- API 500API 500
Typical areasTypical areas
CLASS I, DIVISION 1 CLASS I, DIVISION 1 API 500API 500
yp c e syp c e s
Inadequately ventilated pump rooms for flammable gas or forInadequately ventilated pump rooms for flammable gas or forInadequately ventilated pump rooms for flammable gas or for Inadequately ventilated pump rooms for flammable gas or for volatile, flammable liquidsvolatile, flammable liquids
VentingVenting
Oily waste water sewer / basinsOily waste water sewer / basins
CLASS I, DIVISION 2 CLASS I, DIVISION 2 -- API 500API 500
• Flammable gas or vapor concentration is likely to exist in the air only under abnormal operating conditions
• Vapours or gases will normally be confined within closedcontainers or closed systems from which they can escape onlyduring abnormal conditions such as accidental release/ leak
• Locations adjacent to Division 1 areas
• ignitable concentrations of gases or vapors are normallyprevented by positive mechanical ventilation
CLASS I, DIVISION 2 CLASS I, DIVISION 2 -- API 500API 500
A Class I Zone 0 location is location where ignitableA Class I, Zone 0 location is location where ignitable concentrations of flammable gases, vapors or liquids;are present continuously; or are present for long periods or time.
CLASS I ZONE 1CLASS I, ZONE 1
A Class I, Zone 1 location is location where ignitable concentrationsof flammable gases, vapors or liquids:• are likely to exist under normal operating conditions;• are likely to exist under normal operating conditions;• may exist frequently because of repair or maintenance operations• adjacent to a Zone 0 location
CLASS I, ZONE 2
A Class I, Zone 2 location is location where :• Flammable gas or vapor concentration is likely to exist in the air
only under abnormal operating conditionsonly under abnormal operating conditions • volatile flammable liquids or flammable gases or vapor exist, but
are normally confined within closed containers and adequately ventilated;
• ignitable concentrations of gases, vapors or liquids are normally prevented by positive mechanical ventilation.
• adjacent to a Zone 1 location
CLASS I DIVISION/ ZONE AREA CLASS I DIVISION/ ZONE AREA CALSSIFICATION COMPARISONCALSSIFICATION COMPARISON
API RP 500 API RP 505/ NEC/ European Std.
Division 1:
Where ignitable concentrations of
Zone 0:
Where ignitable concentrations of
flammable gases, vapors or liquids can
exist all of the time or some of the time
under normal operating conditions
flammable gases, vapors or liquids can
exist all of the time or for long periods of
time under normal operating conditions
Zone 1:
Where ignitable concentrations of
flammable gases vapors or liquids can exist
some of the time under normal operatingsome of the time under normal operating
conditions
Division 2: Where ignitable concentrations of
Zone 2: Where ignitable concentrations ofWhere ignitable concentrations of
flammable gases, vapors or liquids are not
likely to exist under normal operating
conditions
Where ignitable concentrations of
flammable gases, vapors or liquids are not
likely to exist under normal operating
conditions
HAZARDOUS AREA CLASSIFICATIONS SYMBOLSHAZARDOUS AREA CLASSIFICATIONS SYMBOLS
API 500 API 505 SYMBOLS
CLASS I, ZONE 0,
CLASS I, DIVISION 1 CLASS I, ZONE 1
CLASS I, DIVISION 2 CLASS I, ZONE 2
CONDITION AFFECTING EXTENT OF CONDITION AFFECTING EXTENT OF HAZARDOUS AREASHAZARDOUS AREAS
What is Explosion Protected Equipment?What is Explosion Protected Equipment?
Fuel Oxygen
Heat/ Sparks
Equipment which is constructed in such way that one of the 3 elements of fire triangleEquipment which is constructed in such way that one of the 3 elements of fire triangleis removed, such that the possibility of of explosion is eliminated
l fl f (EX d)(EX d)Flameproof Flameproof (EX d)(EX d)
Increased Safety Increased Safety (Ex e )(Ex e )
NonNon--Sparking Sparking (Ex n )(Ex n )
Pressurization Pressurization (Ex p )(Ex p )
Intrinsically Safe Intrinsically Safe (Ex i )(Ex i )
OTHER TYPES OF EXPLOSION PROTECTIONOTHER TYPES OF EXPLOSION PROTECTIONUn Popular typesUn Popular types
Powder filled Powder filled Ex ‘q’Ex ‘q’ typetype
il i dil i d E ‘ ’E ‘ ’Oil immersed Oil immersed Ex ‘o’Ex ‘o’ typetype
Special Special Ex ‘s’Ex ‘s’ typetype
EncapsulatedEncapsulated Ex ‘m’Ex ‘m’ typetypeEncapsulated Encapsulated Ex ‘m’Ex ‘m’ typetype
Ventilated Ventilated Ex ‘v’Ex ‘v’ typetype
EXPLOSIONPROOF EQUIPMENTEXPLOSIONPROOF EQUIPMENT
Equipment that has an enclosure capable of :• withstanding an explosion of specified gas or vapor that
is expected to occur within the enclosure• preventing the ignition of specified gas or vapor
surrounding the enclosure due to sparks, flashes orexplosion of the gas or vapor within the enclosure, and
• operating at an external temperatures that will not ignitea specified gas or vapor surrounding the enclosure
WITHSTANDING THE PRESSURE OF AN WITHSTANDING THE PRESSURE OF AN EXPLOSIONEXPLOSIONEXPLOSIONEXPLOSION
The ability of an enclosure to withstand an explosion without rupture orpermanent distortion is dependent upon:
th t th f th l t i l•the strength of the enclosure material•securement means, such as bolts, nuts
The strength of the enclosure material and securement means is determined byg ythe following requirements :
•type of metal or metal alloy (zinc & magnesium are not allowed)•type of plastic (including resistance to chemical atmospheres)•type of plastic (including resistance to chemical atmospheres)•casting / molding design•hydrostatic pressure testing
EX ‘d’ Type FLAMEPROOF EX ‘d’ Type FLAMEPROOF EQUIPMENTEQUIPMENT
AA ff ii ii hi hhi h i h dii h di i li l l il i ffAA typetype ofof protectionprotection inin whichwhich withstandingwithstanding anan internalinternal explosionexplosion ofof aaflammableflammable mixturemixture ofof aa specifiedspecified gasgas oror vaporvapor mixture,mixture, relieverelieve thethe internalinternalexplosion/explosion/ pressurepressure viavia enclosureenclosure flameflame pathspaths suchsuch asas lidslids andand glandsglands.. PreventPreventtransmissiontransmission ofof hothot gassesgasses andand flameflame throughthrough jointsjoints oror aperturesapertures inin thethetransmissiontransmission ofof hothot gassesgasses andand flameflame throughthrough jointsjoints oror aperturesapertures inin thetheenclosureenclosure assemblyassembly suchsuch asas wouldwould igniteignite thethe externalexternal explosiveexplosive atmosphereatmosphere
EXPLOSION PROOFEXPLOSION PROOF
When an explosion occurs, the surrounding hazardous environment is not exposed to hot gases or hot surfaces.
Only cooled gases esc apeesc ape
Hot gases are c ooled as they pass through threads Threaded join
5 full threadsminimum
Internalpressure
Hot flaminggasespressure gases
H t l d th th h th th dHot gases are cooled as they pass through the threads
Internalpressure
Hot flaminggases
Cooledgas
gases
Hot gases are cooled as they pass across a machined flanged joint
Normal Clearance
Clearance during explosion
Effect of internal explosion on cover-to-body joint
INTRINSICALLY SAFE EQUIPMENT & INTRINSICALLY SAFE EQUIPMENT & N N QU NN N QU NCIRCUITS (Ex ‘i’ )CIRCUITS (Ex ‘i’ )
AA typetype ofof protectionprotection whichwhich anyany energy/energy/ heatheat releasedreleased byby thethe electricalelectricalequipmentequipment isis incapableincapable ofof causingcausing ignitionignition ofof aa givengiven explosiveexplosive atmosphereatmosphere..EE ‘i ’‘i ’ i bli bl ff ii i i ii i i ii ll ii i hi h i hi h i li lExEx ‘ia’‘ia’ incapableincapable ofof causingcausing ignitionignition inin normalnormal operation,operation, withwith eithereither aa singlesinglefault,fault, oror anyany combinationcombination ofof twotwo faultsfaults appliedappliedEx ‘ib’Ex ‘ib’ incapable of causing ignition in normal operation, with single fault incapable of causing ignition in normal operation, with single fault appliedappliedappliedapplied
INCREASED SAFETY EQUIPMENT (E ‘ ’)INCREASED SAFETY EQUIPMENT (E ‘ ’)INCREASED SAFETY EQUIPMENT (Ex ‘e’)INCREASED SAFETY EQUIPMENT (Ex ‘e’)
A type of protection which is designed and rated to prevent anexplosion and reduce the risk of both explosive/ flammable gas ingressand an ignition source.Generally there are 3 aspects that are covered by the additional safetymeasures:
•Parts that may cause sparks in normal use•Creepage and clearance distance to prevent trackingCreepage and clearance distance to prevent tracking•Prevention of any part of the equipment, including internalcomponents, from exceeding the temperature rating equipment
PRESSURIZATION TYPE (Ex ‘p’ )PRESSURIZATION TYPE (Ex ‘p’ )
NONNON--SPARKING TYPE EQUIPMENT (Ex ‘n’ )SPARKING TYPE EQUIPMENT (Ex ‘n’ )
A type of protection applied to electrical apparatus where the materialused in this type of equipment will not produce any sparks such that itis not capable of igniting a surrounding atmosphere and a faultcapable of causing ignition is not likely to occurcapable of causing ignition is not likely to occur
POWDER FILLED TYPE EQUIPMENT ( Ex ‘q’) POWDER FILLED TYPE EQUIPMENT ( Ex ‘q’)
A type of protection applied to electrical apparatus whereEquipment enclosure is filled with quartz /sand so that if any arcoccurring within the enclosure of electrical equipment it will noti it th di t hignite the surrounding atmosphere
OIL IMMERSED TYPE EQUIPMENT (Ex ‘o’) OIL IMMERSED TYPE EQUIPMENT (Ex ‘o’)
A type of protection applied to electrical apparatus where adevice is encased in molded resin, such a way that anexplosive atmosphere should not occur.
Hermetic Sealing Ex ‘h’Hermetic Sealing Ex ‘h’
A type of protection applied to electrical apparatus where thisdevices is constructed such that external atmosphere can notdevices is constructed such that external atmosphere can notgain access to the interior/ enclosure, in which a seal is madeby fusion eg. Soldering, brazing.
SPECIAL TYPE EQUIPMENT (Ex ‘s’) SPECIAL TYPE EQUIPMENT (Ex ‘s’)
SELECTION OF ELECTRICAL EQUIPMENT IN SELECTION OF ELECTRICAL EQUIPMENT IN HAZARDOUS AREASHAZARDOUS AREASHAZARDOUS AREASHAZARDOUS AREAS
How to select equipment for various areas/ locations?How to select equipment for various areas/ locations?
Selection Criteria• Gas Grouping (based on ignition energy)• Temperature ClassificationTemperature Classification• Classified Zones/ Division
Definition : MESGDefinition : MESG
MESG (Maximum Experimental Safe GAP)
The maximum clearance between two parallel metal surfaces that hasThe maximum clearance between two parallel metal surfaces that hasbeen found, under specified test conditions, to prevent an explosion ina test chamber from being propagated to a secondary chambercontaining the same gas or vapor at the same concentration.g g p
MESG (Ma im m E perimental Safe GAP)MESG (Ma im m E perimental Safe GAP)MESG (Maximum Experimental Safe GAP) MESG (Maximum Experimental Safe GAP) diagramdiagram
MESG (Maximum Experimental Safe GAP)Hot Gas
MESG (Maximum Experimental Safe GAP)
explosion
Definition : MIC RatioDefinition : MIC Ratio
MIC (Minimum Igniting Current) RatioThe ratio of the minimum current required to ignite the ignitablemixture of a gas or vapor divided by the minimum current requiredmixture of a gas or vapor, divided by the minimum current requiredto ignite methane gas.
The MIC ratio is based upon the use of methane gas as a base forcomparison to the other gases in question
CLASS I, DIVISION 1 & 2GROUPSGROUPS
g GROUP AA t l-Acetylene
g GROUP BGases or vapors having-Gases or vapors havinggMESG ≤ 0.45 mm orgMIC Ratio ≤ 0.40
Examples are:hydrogen, fuel and combustible process gases containing more than 30 percent hydrogen by volume, butadiene, ethylene oxide, p y g y , , y ,propylene oxide, and acrolein
CLASS I, DIVISION 1 & 2 GROUPS (cont.)
g GROUP CGases or vapors having:g0 45 mm < MESG ≤ 0 75 mm org0.45 mm < MESG ≤ 0.75 mm org0.40 < MIC Ratio ≤ 0.80Examples are:ethyl ether and ethyleneethyl ether and ethylene.
g GROUP DGases or vapors having:p gg0.75 mm < MESGg 0.80 < MIC Ratio Examples are: acetone, ammonia, benzene, butane, cyclopropane, ethanol, gasoline, hexane, methanol, methane, naphtha, and propane
CLASS I ZONE 0 1 AND 2 GROUPSCLASS I, ZONE 0, 1 AND 2 GROUPS
g GROUP II CAtmospheres containing acetylene, hydrogen, or gases or vapors having:
g MESG ≤ 0.50 mm g MIC Ratio ≤ 0.45
CLASS I, ZONE 0, 1 AND 2 GROUPS (cont.)
g GROUP II BAtmospheres containing ethylene or acetaldehyde, or gases orAtmospheres containing ethylene or acetaldehyde, or gases or vapors having: g 0.50 mm < MESG ≤ 0.90 mmg 0.45 MIC Ratio ≤ 0.80
g GROUP II AAtmospheres containing acetone, ammonia, ethyl, alcohol, gasoline, methane , propane or gases or vapors having: g 0.90 mm < MESG g 0.80 < MIC Ratio
CLASS I DIVISION / ZONEGAS GROUP COMPARISON
API 500 API 505
GAS GROUP COMPARISON
API 500 API 505API RP 500
Division 1 and 2 API RP 505/ NEC/ European Std.
Zone 0, 1 and 2 A (acetylene) B (Hydrogen, Butadiene, Ethylene Oxide,
II C (acetylene & hydrogen, Butadiene, Ethylene Oxide, Propylene Oxide, and B (Hydrogen, Butadiene, Ethylene Oxide,
Propylene Oxide, and acrolein) t y e e O de, opy e e O de, a d
acrolein) C (Ethyl Ether and Ethylene) II B (Ethyl Ether and Ethylene) D (Acetone, Ammonia, Benzene, Butane,
Cyclopropane, Ethanol, Gasoline, Hexane Methanol Methane Naphta and
II A (Acetone, Ammonia, Benzene, Butane, Cyclopropane, Ethanol)
Hexane, Methanol, Methane,Naphta and Propane)
TEMPERATURE CLASS COMPARISONTEMPERATURE CLASS COMPARISONTEMPERATURE CLASS COMPARISONTEMPERATURE CLASS COMPARISON
API RP 500 API RP 505/ NEC/ European Std. DIVISION 1 and 2 ZONE 0, 1 and 2
T1 (≤ 4500 C) T1 (≤ 4500 C) 0 0T2 (≤ 3000 C) T2 (≤ 3000 C)
T2A,B,C,D (≤ 2800 C, ≤ 2600, ≤ 2300 , ≤ 2150)
-
T3 ( 2000 C) T3 ( 2000 C)T3 (≤ 2000 C) T3 (≤ 2000 C)T3A,B,C
(≤ 1800 C, ≤ 650, ≤ 1600) -
T4 (≤ 1350 C) T4 (≤ 1350 C)T4 (≤ 135 C) T4 (≤ 135 C)T4A (≤ 1200 C) - T5 (≤ 1000 C) T5 (≤ 1000 C) T6 (≤ 850 C) T6 (≤ 850 C)T6 (≤ 85 C) T6 (≤ 85 C)
CLASS I DIVISION I GROUP CD T3
CLASS I ZONE I GROUP IIA T3
RECOMMENDED PROTECTION METHODS FORRECOMMENDED PROTECTION METHODS FORRECOMMENDED PROTECTION METHODS FOR RECOMMENDED PROTECTION METHODS FOR CLASS I, DIVISION 1CLASS I, DIVISION 1
MotorsMotors-- Ex d, Ex pEx d, Ex p
Transformers & Capacitors Transformers & Capacitors -- Ex dEx d
Control & Instrument Transformers Control & Instrument Transformers -- Ex iEx i
Lighting Fitting Lighting Fitting -- Ex dEx d
Switch Gear & Control Gear Switch Gear & Control Gear -- Ex dEx d
Communication/ Telephone equipment/Meters Communication/ Telephone equipment/Meters -- Ex iEx i
Portable Hand LampsPortable Hand Lamps-- Ex iEx i
RECOMMENDED PROTECTION METHODS FOR RECOMMENDED PROTECTION METHODS FOR CLASS I, DIVISION 2CLASS I, DIVISION 2
MotorsMotors-- Ex d, Ex p, Ex n, Ex e, Ex d, Ex p, Ex n, Ex e,
Transformers & Capacitors Transformers & Capacitors -- Ex d, Ex p Ex d, Ex p (auxiliary devices to be (auxiliary devices to be l d i i d /h i ll l d / i i i ll f )l d i i d /h i ll l d / i i i ll f )located in pressurized room/hermetically sealed / intrinsically safe)located in pressurized room/hermetically sealed / intrinsically safe)
Control & Instrument Transformers Control & Instrument Transformers -- Ex iEx i
Lighting Fitting Lighting Fitting -- Ex d, Ex e, Ex nEx d, Ex e, Ex n
Switch Gear & Control Gear Switch Gear & Control Gear -- Ex d, Ex o, Ex Ex d, Ex o, Ex
Communication/ Telephone equipment/Meters Communication/ Telephone equipment/Meters -- Ex iEx i
Portable Hand LampsPortable Hand Lamps-- Ex iEx iPortable Hand LampsPortable Hand Lamps Ex iEx i
RECOMMENDED PROTECTION METHODSRECOMMENDED PROTECTION METHODSFOR ZONE OFOR ZONE O
No electrical equipment should be allowed. When this is not No electrical equipment should be allowed. When this is not practicable, practicable, Ex ‘ia’Ex ‘ia’ apparatus or circuits to be usedapparatus or circuits to be used
CLASS I, ZONE O AND 1 PROTECTION TECHNIQUES
Area Protection Techniques Zone 0 Intrinsically Safe (2 fault) ‘ia’Zone 0 Intrinsically Safe (2 fault), ia
Class I, Division 1 Intrinsically Safe (2 fault) Zone 1 Encapsulated, ‘m’
‘ ’Powder Filled, ‘q’Purged / pressurized, ‘p’ Any Class I, Zone 0 technique Any Class I Division1 techniqueAny Class I, Division1 technique
CLASS I ZONE 2 PROTECTION TECHNIQUESCLASS I, ZONE 2 PROTECTION TECHNIQUES
Area Protection TechniquesqZone 2 Energy Limited ‘nC’ (‘nL’ in EN50021)
Hermetically Sealed, ‘nC’ Nonincendive, ‘nC’ N S ki ‘ A’Non – Sparking, ‘nA’Pressurization ‘nZ’ (‘nP’ in EN50021) Restricted Breathing, ‘nR’ Sealed Device ‘nC’Sealed Device, nCAny Class I, Zone 0 or 1 technique Any Class I, Division1 or 2 technique
Reduce hazard to life and property that can result from Reduce hazard to life and property that can result from f il lf i f i d i lf il lf i f i d i l l i ll i lfailure or malfunction of industrialfailure or malfunction of industrial--type electrical type electrical system and equipmentsystem and equipment
Fundamentals of Electrical Equipment MaintenanceFundamentals of Electrical Equipment Maintenance
Design to accommodate maintenanceDesign to accommodate maintenanceS h d li iS h d li iScheduling maintenanceScheduling maintenancePersonnel and equipment safetyPersonnel and equipment safetyThe protective schemeThe protective schemeAcceptance testingAcceptance testing
General attention General attention
Enclosure :Enclosure :
Make sure the continuation of function where it shall prevent exposure of Make sure the continuation of function where it shall prevent exposure of live parts and operating mechanism and protect the equipment from live parts and operating mechanism and protect the equipment from exposure to moisture and air contaminants outside the enclosureexposure to moisture and air contaminants outside the enclosureSecurity :Security :
Inspect all doors and access panels to ensure that all hardware is in place Inspect all doors and access panels to ensure that all hardware is in place and in good condition.and in good condition.ggLeakage :Leakage :
Identify of any evidence of leakage and caulk any leaking seemsIdentify of any evidence of leakage and caulk any leaking seems
Moisture :Moisture :
Accumulation may occur even though panel are watertight. The source of Accumulation may occur even though panel are watertight. The source of y g p gy g p gmoisture is condensation due to surface temp drop below the air dew point.moisture is condensation due to surface temp drop below the air dew point.Heating :Heating :
If space heaters are provided make sure that they are in good condition andIf space heaters are provided make sure that they are in good condition andIf space heaters are provided, make sure that they are in good condition and If space heaters are provided, make sure that they are in good condition and operating properly. operating properly. Insulation :Insulation :
Insulation deterioration will be accumulated during the operating whichInsulation deterioration will be accumulated during the operating whichInsulation deterioration will be accumulated during the operating which Insulation deterioration will be accumulated during the operating which detract from its voltage withstanding capability.detract from its voltage withstanding capability.
Electrical distress :Electrical distress :
Areas in which electrical distress is more likely to occur :Areas in which electrical distress is more likely to occur :s w c c c d s ss s y ccs w c c c d s ss s y cc•• Boundaries between two adjoining insulatorsBoundaries between two adjoining insulators•• Boundaries between an insulating member and the grounded metal Boundaries between an insulating member and the grounded metal
structurestructure•• Taped or compounded splices or junctionsTaped or compounded splices or junctions•• Phase to phase or phase to ground bridging path across insulating Phase to phase or phase to ground bridging path across insulating
surface.surface.•• Hidden surface such as busHidden surface such as bus--bar supportbar support
Thermal damage :Thermal damage :Even slightly over design levels for prolonged periods, can significantly Even slightly over design levels for prolonged periods, can significantly h h l i l lifh h l i l lifshorten the electrical life.shorten the electrical life.
Basis for detecting heat damage :Basis for detecting heat damage :DiscolorationDiscolorationDiscolorationDiscolorationCrazing, cracking, flaking of varnish coatingCrazing, cracking, flaking of varnish coatingEmbrittlerment of tape and cable insulationEmbrittlerment of tape and cable insulationDelaminationDelaminationDelaminationDelaminationGeneralized carbonizationGeneralized carbonizationMelting, oozing or exuding of substances from within an insulating Melting, oozing or exuding of substances from within an insulating assemblyassemblyyy
Suggestion for Inclusion in a WalkSuggestion for Inclusion in a Walk--Through InspectionThrough Inspection
Flexible Cords :Flexible Cords :
Check condition for badly worn, improper type, current carrying capacity Check condition for badly worn, improper type, current carrying capacity too small.too small.Plugs and Connectors :Plugs and Connectors :gg
Check for stray strands and loose terminal.Check for stray strands and loose terminal.Receptacle Outlets :Receptacle Outlets :
Ch k f r ntin it f r ndin nn ti nCh k f r ntin it f r ndin nn ti nCheck for continuity of grounding connection.Check for continuity of grounding connection.Portable Equipment :Portable Equipment :
Check for equipment name plate according to the Area classification.Check for equipment name plate according to the Area classification.
Lighting Fixtures :Lighting Fixtures :g gg g
Check for no fixtures should be located close to highly combustible material.Check for no fixtures should be located close to highly combustible material.Equipment Grounding :Equipment Grounding :
Check for broken or loose connection at conduit bonding or equipmentCheck for broken or loose connection at conduit bonding or equipmentCheck for broken or loose connection at conduit bonding or equipment Check for broken or loose connection at conduit bonding or equipment grounding.grounding.Switchgear rooms and MCC rooms :Switchgear rooms and MCC rooms :
Ch k h h l d d f h f fCh k h h l d d f h f fCheck to see that they are clean and used for no other purpose, free of Check to see that they are clean and used for no other purpose, free of storage of any kind ( combustible material ), ventilation should be in working storage of any kind ( combustible material ), ventilation should be in working condition and unobstructed.condition and unobstructed.E l f El i lE l f El i lEnclosures of Electrical parts :Enclosures of Electrical parts :
Check to see that covers secured in place.Check to see that covers secured in place.
All bolts should be in place and tight. Permanent marking should not be All bolts should be in place and tight. Permanent marking should not be obstructed by paint. No modification is permitted w/o reobstructed by paint. No modification is permitted w/o re--certification.certification.Emergency Equipment :Emergency Equipment :
-- Exit lights should all be functioning properly.Exit lights should all be functioning properly.-- Emergency lights should all be in working condition. Periodic test isEmergency lights should all be in working condition. Periodic test isEmergency lights should all be in working condition. Periodic test is Emergency lights should all be in working condition. Periodic test is recommended.recommended.-- Emergency power supply should have periodic check Emergency power supply should have periodic check and running test.and running test.Alarm system such as for fire intrusion smokeAlarm system such as for fire intrusion smoke detection sprinkler anddetection sprinkler and-- Alarm system, such as for fire, intrusion, smoke Alarm system, such as for fire, intrusion, smoke detection sprinkler and detection sprinkler and
fire pump also receive periodic fire pump also receive periodic tests.tests.
Only cooled gases esc apeesc ape
Hot gases are c ooled as they pass through threads Threaded join
5 full threadsminimum
Internalpressure
Hot flaminggasespressure gases
H t l d th th h th th dHot gases are cooled as they pass through the threads
Internalpressure
Hot flaminggases
Cooledgas
gases
Hot gases are cooled as they pass across a machined flanged joint
Normal Clearance
Clearance during explosion
Effect of internal explosion on cover-to-body joint
Sealing fitting
Hazardous area
Push
buttonstation
Combinationswitc h and controller
Motor
button
Unions
S it h
FlexibleJunction
Switch
coupling Junctionbox
ConclusionConclusion
Maintenance :Maintenance :
Proper maintenance will result in electrical apparatus function as expected.Proper maintenance will result in electrical apparatus function as expected.Modification of Certified apparatus :Modification of Certified apparatus :
Modification should not be done to certified “Hazardous classified”Modification should not be done to certified “Hazardous classified”Modification should not be done to certified Hazardous classified Modification should not be done to certified Hazardous classified apparatus unless it is approved by authorized reapparatus unless it is approved by authorized re--certification body.certification body.
MAINTENANCE RECOMMENDATIONS IN MAINTENANCE RECOMMENDATIONS IN HAZARDOUS AREASHAZARDOUS AREAS
DOS AND DON'TS OF HAZARDOUS AREA EQUIPMENT
HAZARDOUS AREASHAZARDOUS AREAS
Dos
• Disconnect electrical supply before opening or working on a non-intrinsically safe enclosure. As matter of safer general practice, all circuits,including IS, be isolated before any work can proceed in the field unlessunder hot work permit . Electrical isolation procedures must be employed.
• Check that threaded covers flat joints rotating shafts bearings andCheck that threaded covers, flat joints, rotating shafts, bearings andoperating shafts are well lubricated and without corrosion. At detailedinspection periods all joints should be cleaned of old grease, matingsurfaces inspected and the appropriate fresh grease applied. It isrecommended practice to use graphite or silicone based lubricants andavoid the use of metallic based greases such as copper or molybdenumbased compounds.
MAINTENANCE RECOMMENDATIONS IN MAINTENANCE RECOMMENDATIONS IN HAZARDOUS AREASHAZARDOUS AREAS
Dos
DOS AND DON'TS OF HAZARDOUS AREA EQUIPMENT (Cont.)
Dos• Check that all flame paths are clean and free from grit or foreign matter when
being closed.• Ensure that all enclosures are properly reassembled and all bolts are in place
and tightened to the correct torque before connecting the supply. Use onlycertified replacement parts designed for that equipment. Do not replace seals(gasket or o-rings) with other than maker's approved parts.
• Check that all unused terminal screws are tightened.Check that all unused terminal screws are tightened.• Check earthing in accordance with installation requirements• Check all door, gland plate or cover fixing screws are intact and spare cable
entries are plugged with the correct type of plug.• Ch k th t f t ' l b l i l fi d t th i t d d t i• Check that manufacturer's label is securely fixed to the equipment and data is
legible.
MAINTENANCE RECOMMENDATIONS IN MAINTENANCE RECOMMENDATIONS IN HAZARDOUS AREASHAZARDOUS AREAS
DOS AND DON'TS OF HAZARDOUS AREA EQUIPMENT (Cont.)
Dos• Check that cable glands threads are tightly fixed to the equipment and cable
armouring is effectively retained by the cable gland armour clamping cones.• Fit th f l bl l d h th t l i f (E )• Fit weatherproof seals on cable glands when they enter explosion proof (Ex)
Equipment• Check that unused conductors of explosion proof (Ex) Equipment enclosures
are terminated in certified terminals. Ensure spare conductors in an Ex'i'penclosure are linked to earth.
• Replace faulty I.S. barriers with only the correct type.• Check that the screw thread on the gland correctly matches that on the
enclosure as incorrect matching of threads can invalidate the flameproofingenclosure, as incorrect matching of threads can invalidate the flameproofing.• Flange faces to be smooth & original (to be careful while opening stuck
covers)
MAINTENANCE RECOMMENDATIONS IN MAINTENANCE RECOMMENDATIONS IN HAZARDOUS AREASHAZARDOUS AREAS
DOS AND DON'TS OF HAZARDOUS AREA EQUIPMENT (Cont.)
Don't's
• Do not short circuit the hazardous area circuit• Do not make additional openings, add terminals or carry out other alterations
which may affect certification.y• Do not cover flame path or name plate with paint when painting.• Do not use sharp objects such as screwdrivers to open an enclosure
since it may damage the flame path and render enclosure unsafe.• Do not use uncertified test equipment in hazardous areas such as• Do not use uncertified test equipment in hazardous areas such as
multimeters and meggers to test equipment eg motors, even if disconnectedfrom the supply, without a hot work clearance.
MAINTENANCE RECOMMENDATIONS IN MAINTENANCE RECOMMENDATIONS IN HAZARDOUS AREASHAZARDOUS AREAS
DOS AND DON'TS OF HAZARDOUS AREA EQUIPMENT (Cont.)
HAZARDOUS AREASHAZARDOUS AREAS
( )
Don't's
• Do not try to repair faulty I.S Barriers. They only replaceable components on some isolated types is the safe area side fuse. If replacing the fuse, the correct type and rating must be used.
• Do not install more than one conductor in a terminal clamp of an Ex'e' or 'n'• Do not install more than one conductor in a terminal clamp of an Ex e or n rated enclosure. Use certified cross connection inserts to link terminals.
• Any equipment which is originally flameproof may loose its integrity if not maintained properly
• No site modification / alteration
“ELECTRICAL EQUIPMENT USED IN HAZARDOUS ARAES ARE SPECIAL AND THEY NEEDS TO BE TREATED SPECIAL”,
Any equipment which is originally Explosion proof (EX) may loose its integrity if not maintained properly or modified
USEFUL REFERENCE BOOKS ON HACUSEFUL REFERENCE BOOKS ON HAC
Classification of Hazardous Locations,I.Chem. Classification of Hazardous Locations,I.Chem. E. Cox, A.W., Lees, F.P. E. Cox, A.W., Lees, F.P. and Ang, M.L, 1990and Ang, M.L, 1990IP Model Code of Safe Practice, 1990, Part 15, Area Classification Code IP Model Code of Safe Practice, 1990, Part 15, Area Classification Code for Petroleum Installationsfor Petroleum InstallationsNFPA 69, 1992, Explosion Prevention SystemsNFPA 69, 1992, Explosion Prevention SystemsICI/RoSPA, 1972, ICI Electrical Installations CodeICI/RoSPA, 1972, ICI Electrical Installations CodeNFPA 325M, Properties of Flammable Liquids, gases and solidsNFPA 325M, Properties of Flammable Liquids, gases and solidsElectrical Safety in Hazardous LocationsElectrical Safety in Hazardous Locations William Calder & Ernest CWilliam Calder & Ernest CElectrical Safety in Hazardous Locations, Electrical Safety in Hazardous Locations, William Calder & Ernest C. William Calder & Ernest C. MagisonMagison
HACHAC--RELEVANT INTERNATIONAL STANDARDSRELEVANT INTERNATIONAL STANDARDS
API RP 500/ 550API RP 500/ 550Area Classification of Petroleum InstallationsArea Classification of Petroleum InstallationsIEC 79IEC 79--10 :199510 :1995 --Electrical Apparatus for Explosive Gas Atmospheres partElectrical Apparatus for Explosive Gas Atmospheres partIEC 79IEC 79 10 :199510 :1995 Electrical Apparatus for Explosive Gas Atmospheres, part Electrical Apparatus for Explosive Gas Atmospheres, part
10 Classification of hazardous areas10 Classification of hazardous areasIP Part 15, 1990IP Part 15, 1990-- Area Classification Code for Petroleum InstallationsArea Classification Code for Petroleum InstallationsBS EN 60079BS EN 60079 1010 : 1996: 1996 Electrical Apparatus for Explosive GasElectrical Apparatus for Explosive GasBS EN 60079BS EN 60079--1010, : 1996 , : 1996 --Electrical Apparatus for Explosive Gas Electrical Apparatus for Explosive Gas
Atmospheres, part 10 Classification of hazardous areasAtmospheres, part 10 Classification of hazardous areasBS 5345, 1983BS 5345, 1983--Selection, installation and maintenance of electrical apparatus Selection, installation and maintenance of electrical apparatus
for use in potentially explosive atmospheres (other than mining applicationsfor use in potentially explosive atmospheres (other than mining applicationsfor use in potentially explosive atmospheres (other than mining applications for use in potentially explosive atmospheres (other than mining applications or explosive manufacturing), part 2, Recommendations for particular or explosive manufacturing), part 2, Recommendations for particular industrial situationsindustrial situations
