When using a computer within hazardous environments, there is a class and section guideline available to establish which environments certain computers have the ability to operate within. This document explains this guideline.

1.  What Class Rating is the equipment to be used in?
Classes are used to define the explosive or ignitable substances that are
present in the atmosphere, the two classes are:
            Class I    -    Flammable gases or liquid vapors
            Class II   -    Ignitable metal, carbon or organic dusts

2.  What Group Rating is associated with the environment?
Groups are used to define substances by rating their explosive or ignitable
nature, in relation to other known substances.
                                    TYPICAL Class I Substances
            Group A    -    Acetylene
            Group B    -    Hydrogen or > 30% Hydrogen by volume
            Group C    -    Ethyl Ether& Ethylene
            Group D    -    Acetone, Ammonia, Benzene & Gasoline
                                    TYPICAL Class II Substances
            Group E    -    Aluminum, Magnesium & Alloys
            Group F    -    Carbon, Coke & Coal
            Group G   -    Flour, Grain, Wood, Plastic & Chemicals

3.  What Division Rating is the equipment to be used in?
Divisions are used to determine the degree of hazard by determining the
explosive or ignitable substance's expected concentration in the atmosphere.
            Division 1    -    Contains substances under normal conditions
            Division 2    -    Contains substances under abnormal conditions