B.1 North American Classification of Hazardous Locations, Continued
Methods of Protection |
| The following table summarizes available methods of protection for use |
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| in given locations. |
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Protection Concept |
| Designation | Permitted Use | Principle |
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Explosionproof |
| XP | Division 1 & 2 | Contains explosion and |
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| quenches flame. |
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Intrinsic Safety |
| IS | Division 1 & 2 | Limit energy of sparks under |
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| normal and fault conditions. |
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Pressurized |
| Type X and Y | Division 1 | Keeps flammable gas out. |
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Pressurized |
| Type Z | Division 2 | Keeps flammable gas out. |
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Nonincendive |
| NI | Division 2 | No arcs, sparks or hot surfaces |
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| under normal conditions |
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Temperature Classification
Equipment intended for installation directly within the hazardous location classification must also be classified for the maximum surface temperature that can be generated under normal or fault conditions as referenced to either 40°C (104°F) or the maximum operating ambient of the equipment (whichever is greater). The maximum surface temperature must be less than the minimum autoignition temperature of the hazardous atmosphere present. The temperature shall be indicated in identification numbers as listed in the following table.
Maximum Temperature | Identification Number | ||
Degrees C | Degrees F | ||
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450 | 842 | T1 | |
300 | 572 | T2 | |
280 | 536 | T2A | |
260 | 500 | T2B | |
230 | 446 | T2C | |
215 | 419 | T2D | |
200 | 392 | T3 | |
180 | 356 | T3A | |
165 | 329 | T3B | |
160 | 320 | T3C | |
135 | 275 | T4 | |
120 | 248 | T4A | |
100 | 212 | T5 | |
85 | 185 | T6 | |
Continued on next page
2/05 | ST 3000 Release 300 Installation Guide | 85 |