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Ignition Protection Categories

Symbol Standard Explanation Application
Area
“o” IEC 60079-6 Oil immersed apparatus: Zone 1 + 2
EN 60079-6 Electrical equipment or parts of such equipment
are immersed in oil.

“p” IEC 60079-2 Pressurized enclosure: Zone 1 + 2
EN 60079-2 The ingress of the external (explosive) atmos-
phere into the electrical equipment housing is
prevented by maintaining a protective gas inter-
nally at a pressure above that of the external
atmosphere.
“q” IEC 60079-5 Powder-filled apparatus: Zone 1 + 2
EN 60079-5 Filling the electrical equipment housing with fine
grain sand prevents the ignition of a surrounding
explosive atmosphere by an electric arc genera-
ted in the housing.

“d” IEC 60079-1 Flameproof enclosure: Zone 1 + 2
EN 60079-1 The parts that could ignite an explosive atmos-
phere are encapsulated in a housing, which
will withstand the explosion pressure within the
housing.
“e” IEC 60079-7 Increased safety: Zone 1 + 2
EN 60079-7 Additional measures applied to achieve increa-
sed security against the possibility of excessive
temperatures and the occurrence of arcs or
sparks.
“i” IEC 60079-11 Intrinsic safety: Zone 1 + 2
EN 60079-11 Power circuit in which no sparks or thermal following
effects can occur and cause the ignition of a cer- special
tain explosive atmosphere. testing
Zone 0

“n” IEC 60079-15 Non-sparking: Zone 2
EN 60079-15 Electrical equipment of group II for use in areas
in which an explosive mixture of gas, vapor or
mist is unlikely to occur during normal operation
and, if it does, will be for a short period.
“m” IEC 60079-18 Cast encapsulation: Zone 1 + 2
EN 60079-18 Dangerous electrical equipment is embedded in
a cast mass. This corresponds approximately to
the known special Ex s protection type.
IEC 60079-25 Intrinsically safe electrical systems “i”: Zone 1 + 2
EN 60079-25 Assembly of interconnected electrical equipment following
in which the circuits intended for use, as a whole special
or in part, in hazardous environments are intrin- testing
sically safe. It is documented accordingly in the Zone 0
system description.

IEC / TS FISCO standard:
60079-27 Electrical equipment for explosive gas atmosphe-
res – Part 27: Fieldbus intrinsically safe concept
(FISCO) and Fieldbus non-incendive concept
(FNICO).

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