INTRINSICALLY SAFE CLASSIFICATION
Classification of Hazardous Areas (Division)
Hazardous areas are classified as Division 1 or 2 as shown below. Since a Division 1 area is considered most hazardous, a transceiver approved for a specific Division 1 atmosphere can also be used in the same Division 2 atmosphere. The intrinsically safe rating applies to Division 1 areas and the nonincendive rating applies to Division 2 areas.
Class I and II Materials (Gases, Vapors, and Dusts)
DivisionArea
1An area where there is or could be an explosive atmosphere most of the time in normal operations.
2An area where an explosive atmosphere exists only as a result of a fault (something going wrong).
Class III Materials (Fibers or Flyings)
DivisionArea
1An area in which easily ignitable fibers or materials producing combustible flyings are handled, manufactured, or used.
2An area in which easily ignitable fibers are stored or handled. An exception is in process of manufacture.
Classification of Atmospheres (Class/Group)
For the purposes of testing and approval, various atmospheric mix- tures have been grouped on the basis of their hazardous characteristics. Equipment is approved for a class of material and also for the specific group of gas, vapor, or dust in that class. Class I materials include gases and vapors, Class II materials include combustible dusts, and Class III materials include ignitable fibers or flyings. The typical hazardous mate- rials in each group and class are shown in the following table.
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