Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Personal
Definition(s)
Personal
Equipment intended to be supported by a person’s body during normal use. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsTransportable
Definition(s)
Transportable
Equipment not intended to be carried by a person nor intended for fixed installation which can be moved when energized. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsFixed
Definition(s)
Fixed
Equipment fastened to a support, or otherwise secured in a specific location when energized. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsSafety Extra-low Voltage System (SELV)
Definition(s)
Safety Extra-low Voltage System (SELV)
Electric system in which the voltage cannot exceed the value of extra-low voltage:- under normal conditions and
- under single fault conditions, including earth faults in other electric circuits.
Protective Extra-low Voltage System (PELV)
Definition(s)
Protective Extra-low Voltage System (PELV)
Electric system in which the voltage cannot exceed the value of extra-low voltage:- under normal conditions, and
- under single fault conditions, except earth faults in other electric circuits.
Protection by Enclosure “t”
Definition(s)
Protection by Enclosure “t”
Type of protection whereby all electrical equipment is protected by an enclosure to avoid ignition of a dust layer or cloud. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsEncapsulation “m”
Definition(s)
Encapsulation “m”
Type of protection whereby parts that are capable of igniting an explosive atmosphere by either sparking or heating are enclosed in a compound in such a way that the explosive atmosphere cannot be ignited under operating or installation conditions. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsPowder Filling “q”
Definition(s)
Powder Filling “q”
Type of protection in which the parts capable of igniting an explosive gas atmosphere are fixed in position and completely surrounded by filling material to prevent the ignition of an external explosive atmosphere. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsOil-immersion “o”
Definition(s)
Oil-immersion “o”
Type of protection in which the electrical equipment or parts of the electrical equipment are immersed in a protective liquid in such a way that an explosive gas atmosphere which may be above the liquid or outside the enclosure cannot be ignited. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsAssociated Energy-limited Apparatus
Definition(s)
Associated Energy-limited Apparatus
Electrical equipment which contains both energy-limited and non-energy-limited circuits and is constructed so that the non-energy-limited circuits cannot adversely affect the energy-limited circuits. Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global StandardsEnergy-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 Standards