Glossary
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Energy-limited Apparatus
Definition(s)
Energy-limited Apparatus
Electrical equipment in which the circuits and components are constructed according to the concept of energy limitation. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsType of Protection “n”
Definition(s)
Type of Protection “n”
Type of protection applied to electrical equipment such that, in normal operation and in certain specified abnormal conditions, it is not capable of igniting a surrounding explosive atmosphere. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsLeakage Compensation
Definition(s)
Leakage Compensation
Flow of protective gas sufficient to compensate for any leakage from the pressurized enclosure and its ducts. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsContinuous Dilution
Definition(s)
Continuous Dilution
Continuous supply of a protective gas, after purging, at such a rate that the concentration of a flammable substance inside the pressurized enclosure is maintained at a value outside the explosive limits at any potential ignition source (that is, outside the dilution area). Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsPressurization “p”
Definition(s)
Pressurization “p”
Technique of guarding against the ingress of the external atmosphere into an enclosure by maintaining a protective gas therein at a pressure above that of the external atmosphere. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsMaximum External Inductance to Resistance Ratio (Lo/Ro)
Definition(s)
Maximum External Inductance to Resistance Ratio (Lo/Ro)
Maximum value of ratio of inductance to resistance that can be connected to the external connection facilities of the electrical apparatus without invalidating intrinsic safety. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsIntrinsically Safe Sub-circuit
Definition(s)
Intrinsically Safe Sub-circuit
Part of an intrinsically safe circuit which is galvanically isolated from another part or other parts of the same intrinsically safe circuit. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsIntrinsically Safe Electrical System
Definition(s)
Intrinsically Safe Electrical System
Assembly of interconnected items of electrical equipment, described in a descriptive system document, in which the circuits or parts of circuits intended to be used in an explosive atmosphere are intrinsically safe. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsSystem, Intrinsically Safe
Definition(s)
System, Intrinsically Safe
An assembly of interconnected intrinsically safe apparatus, associated apparatus, and interconnecting cables in which those parts of the system that may be used in hazardous (classified) locations are intrinsically safe circuits. An intrinsically safe system may include more than one intrinsically safe circuit. Source: API Recommended Practice 14FZ, Recommended Practice for Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations, Second Edition, May 2013. Global Standards Source: API RP 14F, Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class 1, Division 1 and Division 2 Locations, Fifth Edition, July 2008. Global StandardsSimple Apparatus
Definition(s)
Simple Apparatus
A device that will not generate or store more than 1.2 V, 0.1 A, 25 mW, or 20 ìJ. Examples are switches, thermocouples, light-emitting diodes, connectors, and resistance temperature detectors (RTDs). Apparatus reliant on voltage or current limiting or suppression devices for remaining within the limits given in the definition, and sensors (e.g. certain gas detector sensors) that utilize catalytic reaction or other electrochemical mechanisms are excluded by IEC 60079-11 from the category of “simple apparatus”. Temperature limitations as described in 4.2 are applicable to simple apparatus.
Source: API Recommended Practice 14FZ, Recommended Practice for Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations, Second Edition, May 2013. Global StandardsSimple Apparatus
Electrical component or combination of components of simple construction with well-defined electrical parameters which is compatible with the intrinsic safety or energy-limited safety of the circuit in which it is used. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsGalvanic Isolation
Definition(s)
Galvanic Isolation
Arrangement within an item of intrinsically safe apparatus or associated apparatus which permits the transfer of signals or power between two circuits without any direct electrical connection between the two. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsIntrinsically Safe Apparatus
Definition(s)
Intrinsically Safe Apparatus
Electrical apparatus in which all the circuits are intrinsically safe. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsAssociated Apparatus
Definition(s)
Associated Apparatus
Electrical apparatus which contains both intrinsically safe circuits and non-intrinsically safe circuits and is constructed so that the non-intrinsically safe circuits cannot adversely affect the intrinsically safe circuits. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsAssociated Apparatus
Apparatus used in intrinsically safe systems in which the circuits are not necessarily intrinsically safe themselves but affect the energy in the intrinsically safe circuits and are relied on to maintain intrinsic safety, see NEC Articles 504.4 and 505.8 for additional details.
Source: API Recommended Practice 14FZ, Recommended Practice for Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations, Second Edition, May 2013. Global StandardsTime (tE)
Definition(s)
Time (tE)
Time taken for an a.c. rotor or stator winding, when carrying the initial starting current IA, to be heated up to the limiting temperature from the temperature reached in rated service at the maximum ambient temperature. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsStarting Current Ratio (IA/IN)
Definition(s)
Starting Current Ratio (IA/IN)
Ratio between initial starting current IA and rated current IN. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsInitial Starting Current (IA)
Definition(s)
Initial Starting Current (IA)
Highest r.m.s. value of current absorbed by an a.c. motor at rest or by an a.c. magnet with its armature clamped in the position of maximum air gap, when supplied at the rated voltage and rated frequency. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsIncreased Safety “E”
Definition(s)
Increased Safety “E”
Type of protection applied to electrical equipment in which additional measures are applied so as to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks in normal service or under specified abnormal conditions. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsPressure-Piling
Definition(s)
Pressure-Piling
Increased pressure resulting from an ignition, in a compartment or subdivision of an enclosure due to a gas mixture being pre-compressed, e.g. due to a primary ignition in another compartment or subdivision. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsFlameproof Enclosure “d”
Definition(s)
Flameproof Enclosure “d”
Type of protection in which the parts capable of igniting an explosive gas atmosphere are provided with an enclosure which can withstand the pressure developed during an internal explosion of an explosive mixture and which prevents the transmission of the explosion to the explosive gas atmosphere surrounding the enclosure. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsZone 22
Definition(s)
Zone 22
Area in which an explosive atmosphere in the form of a cloud of dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsZone 21
Definition(s)
Zone 21
Area in which an explosive atmosphere in the form of a cloud of dust in air is likely to occur, occasionally, in normal operation. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsZone 20
Definition(s)
Zone 20
Area in which an explosive atmosphere in the form of a cloud of dust in air is present continuously, or for long periods or frequently. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsZones
Definition(s)
Zones
Hazardous areas classified into zones based upon the frequency of the occurrence and duration of an explosive atmosphere. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsMaximum Permissible Surface Temperature
Definition(s)
Maximum Permissible Surface Temperature
Highest temperature that a surface of electrical equipment is allowed to reach in practical service to avoid ignition. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsHybrid Mixture
Definition(s)
Hybrid Mixture
Mixture of a flammable gas or vapour with a combustible dust. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsGroup
Definition(s)
Group
Group of electrical equipment for explosive atmospheres> classification of electrical equipment related to the explosive atmosphere for which it is to be used Note 1 to entry: Electrical equipment for use in explosive atmospheres is divided into three groups:- Group I: electrical equipment for mines susceptible to firedamp;
- Group II (which can be divided into subgroups): electrical equipment for places with an explosive gas atmosphere, other than mines susceptible to firedamp;
- Group III (which can be divided into subgroups): electrical equipment for places with an explosive dust atmosphere.