B.2 International Electrotechnical Commission (IEC) Classification of Hazardous Locations, Continued
IEC Methods of | The following table summarizes available methods of protection for use |
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Protection | in given locations. |
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Protection Concept | Designation | Permitted Use | Principle |
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Flameproof | d | Zone 1 & 2 | Contains explosion and |
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| quenches flame. |
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Intrinsic Safety | ia | Zone 0, 1 & 2 | Limits energy of sparks under |
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| 2 faults. |
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| ib | Zone 1 & 2 | Limits energy of sparks under |
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| 1 fault |
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Pressurized | p | Zone 1 | Keeps flammable gases out. |
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Encapsulation | m | Zone 1 & 2 | Keeps flammable gases out. |
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Increased Safety | e | Zone 1 & 2 | No arcs, sparks or hot |
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| surface. |
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Powder Filled | q | Zone 1 & 2 | Contains explosion and |
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| quenches flame. |
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Oil Immersion | o | Zone 1 & 2 | Keeps flammable gases out. |
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nA | Zone 2 | No arcs, sparks or hot |
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| surfaces under normal |
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| conditions. |
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Enclosed Break | nC | Zone 2 | Contains explosion and |
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| quenches flame. |
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Limited Energy | nA | Zone 2 | Limits energy of sparks and |
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| surface temperature under |
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| normal conditions. |
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Restricted Breathing | nR | Zone 2 | Keeps flammable gases out. |
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Continued on next page
90 | ST 3000 Release 300 Installation Guide | 2/05 |