Class II
Combustible dusts
Division 2
•Not normally in the air
•Accumulations normally sufficient to interfere with normal
operation of electrical equipment or oth er ap paratus
•In the air as a result of infrequent malfunctioning of
- handling equipment
- process equipment
•Accumulations are sufficient to interfere with the safe
dissipation of heat from electrical equipment
•Accumulations may be ignitible by abnormal or fa il ur e of
electrical equipment
Group E: Atmospheres containing combustible metal dusts
(regardless of resistivity), dusts of similarly
hazardous characteristics (< 100 kΩ/cm), or
electrically conductive dusts
Group F: Atmospheres containing combustible carbon black,
charcoal, or coke dusts that have > 8% total volatile
material or if these dusts are sensitized so that
they present an explosion hazard and have a
resistivity > 100 kΩ/cm but ≤ 100 MΩ/cm
Group G: Atmospheres containing combustible dusts
having a resistivity > 100 kΩ/cm or electrically
nonconductive dusts
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