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 ignition of a surrounding explosive atmosphere. This includes electrical equipment which contains circuits that are intrinsically safe only under certain conditions, for example under battery supply with mains supply removed.
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 assessed for use in such an atmosphere by applying this standard.
This standard applies to sensors connected to intrinsically safe circuits but does not apply to the protection of catalytic elements for Group IIC or Group IIB + H2.
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 requirement of this standard takes precedence.
Unless otherwise stated, the requirements in this standard are applicable to both intrinsically safe apparatus and associated apparatus, and the generic term "apparatus" is used throughout the standard.
As this standard applies only to electrical equipment, the term "equipment" used in the standard always means “electrical equipment”.
This standard applies to apparatus for use under the atmospheric conditions of IEC 60079-0 with additional requirements for for use at lower atmospheric pressures in the range from 60 kPa (0,6 bar), up to 110 kPa (1,1 bar).