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ElEctrical MaintEnancE in    Hazardous arEa          -Bhagawan Prasad              amieclub@gmail.com
Objective of Area classification   It is a method of:    -Analyzing & classifying the environment    where           Expl...
Why is this Important?   Prevent Electrical Hazards from Starting Fires    and Explosions.   These can be Devastating Lo...
Fire Explosion Triangle   These oxidation   reactions normally   involves the   release of heat &   pressure, which is   t...
Important TermologyHazard: Risk of presence of flammable gas and air mixture.-Hazardous atmosphere: An atmosphere/ environ...
Flammable substancesFlammable substances may be gaseous, liquid or solid- Flammable gas: Are often hydrocarbons & require ...
Concentration: Explosive Limits-LEL Lower explosive limit:Lower or Minimum level of concentration of flammablevapour/gas i...
Concentration: Explosive Limits
Area Classification There are two major classifications prevalent world wide: •NEC (National Electrical Code) of USA •BIS/...
NEC CODEClassifies combustible media as:   •Class I (Flammable gases, vapour & liquid)   •Class II (Combustible dusts)   •...
IEC CODE Classifies combustible media as:    •Group I: Mining (Methane)    •Group II: Other than mining (Gases & Vapors) G...
Examples-   Zone-0:    -   Area like vapour space above storage tank, process tank,        container having flammable mate...
Zone presentation
Gas group   Group Representative Gases   I      All Underground Coal Mining. Firedamp            (methane)   IIA       ...
Temperature class
IP (Ingress Protection) 1st(Protection against solid)            2nd(Protectionagainst    liquid) 0   No protection       ...
Type of ProtectionsVarious method of protection is prevalent & is  suitable for use in hazardous location depending  on th...
Electrical gadgets
Electrical gadgets zone wiseLikelihood of        Hazardous Likelihood of Common Protectiongas/vapour (Above    Area Rating...
FLAME PROOF EX DPerformance Requirements:It is a method of protection, where the equipment isenclosed in an enclosure, whi...
INCREASED SAFETY EX EPerformance Requirements:It is a method of protection,-Wherein additional precautions are taken to pr...
INTRINSICALLY SAFE EX IPerformance Requirements:It is a method of protection,-Explosion is prevented by ensuring that suff...
INTRINSICALLY SAFE EX PPerformance Requirements:It is a method of protection,-Explosion is prevented by purging flammable ...
NON SPARKING SAFE EX NCONCEPT SHARES SIMILARITIES WITH EX E PHILOSOPHY  Performance Requirements:  It is a method of prote...
MATERIAL OF CONSTRUCTIONFollowing material is generally specified:For enclosure:Casting: Al Alloy, CI & CS•Sheet fabricati...
Leveling
Labeling          The letters "CE" stand for "Conformité Européenne"          ("European Conformity"). The Product confirm...
Labeling          The letters "CE" stand for "Conformité Européenne"          ("European Conformity"). The Product confirm...
DO’S IN HAZARDOUS AREA   Use brass made tools   Ensure gasket/seal is not missing   Use recommended 3 pin top/socket on...
Don’ts IN HAZARDOUS AREA   Don’t overload wire /MCB   Don’t use so many jig jag connection or tops   Don’t leave the co...
ou            k   y      a   nT   h
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Electrical maintenance in Hazardous area

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hazardous area classification

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  • Dear Bhagwan Prasad,



    I am to see an excellent presentation of Electrical equipments required for Hazardous areas, Thanks, S.P.Maniktala, Bharat Petroleum Corporation Ltd. Mumbai M9320001076.
       Reply 
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  • VERY GOOD PERSENTATION AND ASK ABOUT ANY PAPER FOR ATEX DIRECTIVE
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Transcript of "Electrical maintenance in Hazardous area "

  1. 1. ElEctrical MaintEnancE in Hazardous arEa -Bhagawan Prasad amieclub@gmail.com
  2. 2. Objective of Area classification It is a method of: -Analyzing & classifying the environment where Explosive atmosphere may occur during. a) Normal Conditions b) Abnormal Conditions. Advantage: -Classification Provides a basis for the selection of suitable electrical apparatus for safe operation
  3. 3. Why is this Important? Prevent Electrical Hazards from Starting Fires and Explosions. These can be Devastating Loss of Life Loss of Facilities Preventable by Following Guidelines Established Cost of Installing Wrong Type of New & Replacement Electrical Equipment
  4. 4. Fire Explosion Triangle These oxidation reactions normally involves the release of heat & pressure, which is the major criteria of an explosion.
  5. 5. Important TermologyHazard: Risk of presence of flammable gas and air mixture.-Hazardous atmosphere: An atmosphere/ environment containingany hazard in a concentration capable of ignition.-Hazardous area: An area/ surrounding where, hazardousatmosphere is likely to occur during normal/ abnormal operation.-Ignition temperature: The lowest temp at which ignition occurs invapour air mixture.
  6. 6. Flammable substancesFlammable substances may be gaseous, liquid or solid- Flammable gas: Are often hydrocarbons & require very little energyto react with atmospheric oxygen.Ex : Methane, Ethane, Hydrogen- Flammable Liquids: Which evaporates at room temperature insufficient quantities to form flammable atmosphere. Ex: Lighter fuel(MS, Naphtha ….)- Flammable Solids: Flammable Dust & fibers which react withatmospheric air to cause explosions in the presence of source ofignition. Ex: (Wood,Coal Dust, metals…..)
  7. 7. Concentration: Explosive Limits-LEL Lower explosive limit:Lower or Minimum level of concentration of flammablevapour/gas in atmosphere which can ignite byarc/spark-HEL/UEL:Upper or maximum level of concentration of flammablevapour/gas in atmosphere which can ignite byarc/spark-Explosive/Flammability Range:Range between LEL to HEL
  8. 8. Concentration: Explosive Limits
  9. 9. Area Classification There are two major classifications prevalent world wide: •NEC (National Electrical Code) of USA •BIS/IEC (Bureau of Indian standard/International Electro technical Commission)
  10. 10. NEC CODEClassifies combustible media as: •Class I (Flammable gases, vapour & liquid) •Class II (Combustible dusts) •Class III (Ignitable Fibers)Groups under different class: Class 1 Class 2 Class 3 Group-A (acetylene) Group-E (Combustible metal dust) No Group (Ignitable fibers) Group-B (Hydrogen) Group-F (Combustible dust having volatile material like: charcoal, coke dust) Group-C (Ethylene) Group-D (Propane)Extent of Hazard: •Division 1: Hazardous media can exist under normal operating condition •Division 2: Hazardous media can exist under abnormal operating condition
  11. 11. IEC CODE Classifies combustible media as: •Group I: Mining (Methane) •Group II: Other than mining (Gases & Vapors) Gas Group: Group-A : Propane Group-B : Ethylene Group-C : Acetylene, Hydrogen & carbon Di Sulphide. Extent of Hazard is defined by Zone: •Zone 0: Hazardous media is continuously present or likely to be present for longer period. •Zone 1: Hazardous media can exist under normal operating condition. •Zone 2: Hazardous media can exist under abnormal operating condition & for a short duration.
  12. 12. Examples- Zone-0: - Area like vapour space above storage tank, process tank, container having flammable material open or close.- Zone-1: - Inadequately ventilated pump house handling flammable material. - Area around imperfectly fitted rim seal of floating roof tank. - Loading of rail Waggon & TT, dispensing stations - Normal start up & shut down of refinery.- Zone-2: - All other area where handling of flammable product is being done in ventilated area & system is designed that vapours are confined within the system,& cannot escape except during abnormal condition.
  13. 13. Zone presentation
  14. 14. Gas group Group Representative Gases I All Underground Coal Mining. Firedamp (methane) IIA Industrial methane, propane, petrol and the majority of industrial IIB Ethylene, coke oven gas and other industrial gases IIC Hydrogen, acetylene, carbon disulphide
  15. 15. Temperature class
  16. 16. IP (Ingress Protection) 1st(Protection against solid) 2nd(Protectionagainst liquid) 0 No protection 0 No protection 1 Solids size > 50 mm 1 Vertically following drops 2 Solids size > 12 mm 2 15 deg from vertical 3 Solids size > 2.5 mm 3 60 deg from vertical 4 Solids size > 1.0 mm 4 Water from all direction 5 Against dust 5 Water jet from all direction 6 Complete against dust 6 Water jet with force 7 Immersion
  17. 17. Type of ProtectionsVarious method of protection is prevalent & is suitable for use in hazardous location depending on the extent of hazard. They are:- Explosion proof or flame proof (Ex d)- Increased safety (Ex e)- Intrinsically safe (Ex i)- Purge protected (Ex p)- Non sparking (Ex n)-Oil filled (Ex o)
  18. 18. Electrical gadgets
  19. 19. Electrical gadgets zone wiseLikelihood of Hazardous Likelihood of Common Protectiongas/vapour (Above Area Rating Ignition Source Basis for ElectricalLEL) EquipmentCertain Zone -0 Extremely rare Intrinsic Safety ExiLikely Zone-1 Rare Flame Proof Ex d Pressurization Ex pUn likely Zone-2 Un likely Increase Safety- Ex e Non Sparking – Ex nMost Un likely Non Possible Normal Electrical Hazardous Equipment
  20. 20. FLAME PROOF EX DPerformance Requirements:It is a method of protection, where the equipment isenclosed in an enclosure, which-Will withstand the internal explosion of flammable gasesthat enter it, without damage.- Do not allow the internal explosion to permeate to thesurroundings through any joints.Constructional Features:Flame path (length & clearances) is ensured as per code.•Suitability:For use in Zone-1 & Zone-2.•
  21. 21. INCREASED SAFETY EX EPerformance Requirements:It is a method of protection,-Wherein additional precautions are taken to provideadditional safety against excessive temperature,occurrence of arc & spark.-These are not capable of withstanding explosion insideenclosure.Constructional Features:•No arcing devices such as fuse & switchgears are used.•Ignition is prevented by use of non sparking components.•Clearances & creep age distances are maintained as percode.Suitability:For use in Zone-2.•
  22. 22. INTRINSICALLY SAFE EX IPerformance Requirements:It is a method of protection,-Explosion is prevented by ensuring that sufficient energyfor ignition of flammable gases is not available.-The Surface temperature does not exceeds auto ignitiontemperature of surrounding flammable gases.Constructional Features:These equipments are primarily low energy electronic device.•Operates at lower voltage & amp.(28V,93mA,0.65W)Suitability:For use in Zone-0 (ia) & Zone-1 (ib).•
  23. 23. INTRINSICALLY SAFE EX PPerformance Requirements:It is a method of protection,-Explosion is prevented by purging flammable media &ensuring non-ingress of flammable media by keepingpositive pressure.•The Surface temperature does not exceeds autoignition temperature of surrounding flammable gases.Constructional Features:Components & devices are installed inside a purge panel.•A positive pressure of uncontaminated air or otherneutral gas is maintained inside the panel.Suitability:For use in Zone-1.•
  24. 24. NON SPARKING SAFE EX NCONCEPT SHARES SIMILARITIES WITH EX E PHILOSOPHY Performance Requirements: It is a method of protection, -Wherein in normal condition, it is not capable of igniting the surrounding explosive atmosphere. -Fault capable of causing the ignition is not likely to occur. Constructional Features: •Components selected are non arcing, non sparking •Enclosed break-Incendive components. •Restricted breathing by sealing & gasketing. Suitability: For use in Zone-2. •
  25. 25. MATERIAL OF CONSTRUCTIONFollowing material is generally specified:For enclosure:Casting: Al Alloy, CI & CS•Sheet fabrication: Al Alloy, SS & MS•
  26. 26. Leveling
  27. 27. Labeling The letters "CE" stand for "Conformité Européenne" ("European Conformity"). The Product confirmas to all requièrent of Heath, Safety & Environnent.Once certified, the equipment is marked by the ‘CE’ (meaningit complies with ATEX and all other relevant directives) and‘Ex’ symbol to identify it as approved under the ATEXdirective.
  28. 28. Labeling The letters "CE" stand for "Conformité Européenne" ("European Conformity"). The Product confirmas to all requièrent of Heath, Safety & Environnent.Once certified, the equipment is marked by the ‘CE’ (meaningit complies with ATEX and all other relevant directives) and‘Ex’ symbol to identify it as approved under the ATEXdirective.
  29. 29. DO’S IN HAZARDOUS AREA Use brass made tools Ensure gasket/seal is not missing Use recommended 3 pin top/socket only Care for glass/fragile items Stop working if too much smell is there Ensure earth connection in switch board/DB box Ensure no glass or sharp item is in working area Use dustbin for cotton waste/CRC/ used bottle Ensure all wiring is neatly tied or dressed Area is not dry grassy Carry recommended torch at night Carry panel key, tool box with you
  30. 30. Don’ts IN HAZARDOUS AREA Don’t overload wire /MCB Don’t use so many jig jag connection or tops Don’t leave the cover open Don’t stand/rest under tank Don’t discharge the capacitor in side LPG/tank area Don’t use rusted or strained nut bolt Don’t use un-sleeved pliers /screw driver Don’t hit metal part with hammer Don’t disconnect the earth bonding
  31. 31. ou k y a nT h
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