Hazardous Locations: classification of areas

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johnbowens
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121371
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Hazardous Locations: classification of areas
Updated:
2012-01-14 00:43:11
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classification areas hazardous NEC electrical
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hazardous electrical installations per NJATC training
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  1. Areas with sealed systems that supply equipment such as a gas-fired boiler are? JATC Hazardous Locations, WB 7
    unclassified locations
  2. Heavier than air gases are those with a vapor density greater than? JATC Hazardous Locations, WB 7 & Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 23
    1
  3. Pyrophoric materials are what? and are used in what classified locations? JATC Hazardous Locations WB 7
    Pyrophoric materials are materials that ignite in contact with the air, such as white phosphorus, and are therefore unclassified do to their extreme and uncontrollable volatility.
  4. Which of the following are Class II location material groups? Group E, F, or G? Hazardous Locations WB 8
    All
  5. The division system of hazardous area classification divides Class 1 locations into how many material groups? JATC Hazardous Locations WB 8
    4: group A,B,C, & D
  6. The Zone system of hazardous area classification divides class I materials into how many groups? JATC Hazardous Locations, WB 8
    3: IIC, IIB, IIA
  7. MESG is an acronym used in hazardous classified areas meaning what? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors,WB 8
    Minimum equipment safe gap
  8. What wiring method(s) are allowed in a class I zone 0 classified location? NJATC Hazardous Locations WB 8

    What is the color coding for intrinsically safe circuits? NEC 504.80C
    Only intrinsically safe, however intrinsically safe is allowed in any hazardous location in general purpose enclosures. 2011 NEC 504.10B

    Light Blue
  9. What material groups are provided for class 3 locations? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, WB 9
    None
  10. The flash point of a liquid involves what form? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors,WB 10
    vapor
  11. Sealed systems, such as metal gas piping systems are generally considered to be ________ locations. Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, WB 10
    unclassified
  12. Combustible dust is finely divided solid material __________ microns or less in diameter. Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP16
    420
  13. Is risk analysis and determining if a location is hazardous a job done in the field? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 18
    NO. In many installations it will require involvement from one or more of the following engineering or design professionals: chemical, process, mechanical, fire protection, civil, environmental, structural, architectural and electrical.
  14. Adequate ventilation is a condition where _________? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 21
    the concentration of combustible material does not exceed 25 percent of the lower flammable limit of the material being considered.
  15. Some Halogenated liquid hydrocarbons with a flammable range but no flash point are considered what? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 22
    unclassified
  16. Two key considerations for design of a ventilated area to create an unclassified location are what? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 22
    Hours of operation and the method of interlocks.
  17. A commercial repair facility is unclassified when there are more than _________ air changes per hour. Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 22
    4
  18. Housekeeping in every situation should be provided as a supplement to dust source elimination and ventilation. True or False? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 22
    False
  19. Explosion proof and dust-ignition proof enclosures are able or not able to contain explosions that occur inside? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 23
    Are able, however they both prevent gases or dust from entering the enclosure and prevent explosions inside the enclosure first. JATC Hazardous Locations WB 21
  20. The primary wiring method for hazardous locations under the Division System continues to be _____, While the primary wiring method used in the Zone system is ____. Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, WB PP 19
    • Division- conduit
    • Zone- cable type
  21. Equipment marking shall specify the class, but division if the equipment is suitable for _________only. NEC 500.8(c)1 &2
    Division 2
  22. As Heavier than air gases are heated, they behave how? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 23
    They become lighter.
  23. What is required at the vertical and horizontal boundaries of the classified locations? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 19 figure 1-03 Note 3
    Sealing fittings
  24. Both the Division and Zone systems can be used in the same facility as long as what? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 25
    Only as long as they don't overlap.
  25. In what areas, the abnormal condition, or first fault, would have to occur in the containment system for the flammable or combustible material before an ignitible concentration could occur? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 37
    Division 2, Zone 2, or Zone 22
  26. In addition to being wrench tight, the number of threads required to be engaged into explosion proof equipment entries is ______, whereas threaded joints must be_____. 2011 NEC 505.9E1 exc. 1
    • threaded joints- 5
    • threaded entries- 4 1/2
  27. What is the maximum spacing for labeling of intrinsically safe wiring raceways, cable trays, and other wiring methods? NEC 504.80B
    25 feet
  28. A combustible gas detection system is a protection technique that is limited to what? JATC Hazardous locations WB PP 23
    Limited to industrial establishments
  29. Define the word approved as described in article 100 of the 2011 NEC.
    Acceptable to the authority having jurisdiction.
  30. Usually the AHJ will base approvals on the use of? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 73
    Listed and labeled equipment.
  31. A nonincendive circuit does not include what type of wiring? NEC 500.1
    Field wiring
  32. The symbol AEx in Zone equipment marking refers to what? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, PP 79
    Built to American Standards
  33. If equipment under the zone system is identified with E, what protection technique is incorporated in the equipment? JATC Hazardous Locations, Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, WB PP 33
    Increased safety NEC 505.9C2(4)
  34. Conduit seals are required to be listed and installed in what locations? Hazardous Locations: 2nd ed. 2007 Int. Ass. of electrical inspectors, WB PP 41 & 2011 NEC 501&2.15C1 fittings

    What class hazardous location does not address seals
    Accessible

    Class 3
  35. Conduit seals shall be installed within _____ of the enclosure. NEC 501.15A1
    18 inches
  36. Metal conduit that contains no unions, couplings, boxes, or fittings, and passes completely through a class 1, Div 1 location with no fittings less than _____ beyond each boundary, shall not require a conduit seal if the termination points of the unbroken conduit are in _______. NEC 501.15A4
    • 12 inches
    • unclassified locations
  37. Examples of fittings employing other than NPT threads include? 2011 NEC 505.16B1 informational note
    • conduit couplings
    • capped elbows
    • unions
    • breather drains.
  38. Type of protection where electrical parts capable of igniting an explosive atmosphere are fixed in position and completely surrounded by filling material such as ______ to prevent the ignition of an external explosive atmosphere is what? 2011 NEC 505.2 definitions
    • glass or quartz powder
    • powder filling Q
  39. Combustible metallic dusts are covered by article 506 of the 2011 NEC Zone 20, 21, and 22 locations for combustible dusts or ignitible fivers/ flyings?
    Are not NEC 506.1
  40. In conduit seals the conductor fill is not permitted to exceed _____ percent of the cross sectional area of the conduit unless specifically listed for a higher percentage. 2011 NEC 501.15C6
    25

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