CEI EN 60079-11

This part of IEC 60079 specifies the construction and testing of
intrinsically safe apparatus intended for use in an explosive
atmosphere and for associated apparatus, which is intended for
connection to intrinsically safe circuits which enter such
atmospheres.

This type of protection is applicable to electrical equipment in
which the electrical circuits themselves are incapable of causing
an explosion in the surrounding explosive atmospheres.

This standard is also applicable to electrical equipment or
parts of electrical equipment located outside the explosive
atmosphere or protected by another Type of Protection listed in IEC
60079-0, where the intrinsic safety of the electrical circuits in
the explosive atmosphere may depend upon the design and
construction of such electrical equipment or parts of such
electrical equipment. The electrical circuits exposed to the
explosive atmosphere are evaluated for use in such an atmosphere by
applying this standard.

The requirements for intrinsically safe systems are provided in
IEC 60079-25.

This standard supplements and modifies the general requirements
of IEC 60079-0, except as indicated in Table 1. Where a requirement
of this standard conflicts with a requirement of IEC 60079-0, the
requirements of this standard shall take precedence.

If requirements in this standard are applicable to both
intrinsically safe apparatus and associated apparatus the term
"apparatus" is used throughout the standard.

This standard is for electrical equipment only; therefore the
term "equipment" used in the standard always means "electrical
equipment".

If associated apparatus is placed in the explosive atmosphere,
it shall be protected by an appropriate Type of Protection listed
in IEC 60079-0, and then the requirements of that method of
protection together with the relevant parts of IEC 60079-0 also
apply to the associated apparatus.