Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Opportunity Maintenance
Definition(s)
Opportunity Maintenance
Maintenance of an item that is deferred or advanced in time when an unplanned opportunity becomes available. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsOperating Time
Definition(s)
Operating Time
Time interval during which an item is in operating state. NOTE Operating time includes actual operation of the equipment or the equipment being available for performing its required function on demand. See also Table 4. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsOperating Time
Time interval during which an item is in an operating state. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsOperating State
Definition(s)
Operating State
State when an item is performing a required function. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global Standards Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsNon-Critical Failure
Definition(s)
Non-Critical Failure
Failure of an equipment unit that does not cause an immediate cessation of the ability to perform its required function. NOTE Non-critical failures can be categorized as “degraded” (3.7) or “incipient” (3.26). Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsModification
Definition(s)
Modification
Combination of all technical and administrative actions intended to change an item. NOTE Modification is not normally a part of maintenance, but is frequently performed by maintenance personnel. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsModification
Combination of all technical and administrative actions intended to change an item. NOTE Modification is not normally a part of maintenance, but is frequently performed by maintenance personnel. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsModification
Change to the design of the equipment which affects material, fit, form or function. Source: IEC 60079-19:2015, Explosive atmospheres – Part 19: Equipment repair, overhaul and reclamation, Edition 3.1, March 2015. Global StandardsModification
Combination of all technical and administrative actions intended to change an item. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsModification:
Modification means a change required by the Regional Supervisor to an EP, DPP, or DOCD (see 30 CFR 550.233(b)(2) and 550.270(b)(2)) that is pending before BOEM for a decision because the OCS plan is inconsistent with applicable requirements. Source: Oil and Gas and Sulphur Operations in the Outer Continental Shelf, 30 CFR 250 (2013). RegulationsMaintenance Man-Hours
Definition(s)
Maintenance Man-Hours
Accumulated duration of the individual maintenance times used by all maintenance personnel for a given type of maintenance action or over a given time interval. NOTE 1 Maintenance man-hours are expressed in units of hours. NOTE 2 As several people can work at the same time, man-hours are not directly related to other parameters like MTTR or MDT (see definitions in Annex C.5). Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsMaintainability (General)
Definition(s)
Maintainability (General)
Ability of an item under given conditions of use, to be retained in, or restored to, a state in which it can perform a required function, when maintenance is performed under given conditions and using stated procedures and resources. NOTE For a more detailed definition and interpretation of maintainability, see Annex C. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsMaintainability (General)
Ability of an item under given conditions of use, to be retained in, or restored to, a state in which it can perform a required function, when maintenance is performed under given conditions and using stated procedures and resources. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsMaintenance Record
Definition(s)
Maintenance Record
Part of maintenance documentation that contains all failures, faults and maintenance information relating to an item. NOTE This record can also include maintenance costs, item availability or up time and any other data where relevant.1Source(s)
1. API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandards
Maintenance Impact
Definition(s)
Maintenance Impact
Impact of the maintenance on the plant or equipment’s function(s). NOTE On the equipment level, two severity classes are defined: critical and non-critical. On plant level, three classes are defined: total, partial or zero impact. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsMaintenance
Definition(s)
Maintenance
Action(s) taken to minimize the likelihood of causes of equipment failure and unscheduled interruptions.- NOTE: This is referred to in API Q2 as “preventive maintenance”.
Maintenance
Upkeep of well control equipment that is performed in accordance with the equipment owner’s preventive maintenance (PM) program and the manufacturer’s guidelines.- NOTE: These procedures may include but are not limited to: inspections, cleaning, polishing, function testing, pressure testing, NDE, and change out of sealing parts and those parts defined in the PM program to be changed either periodically or on a cycle basis.
Maintenance
Actions including inspection, adjustments, cleaning, lubrication, testing, and replacement of expendable parts, as necessary to maintain the serviceability of the equipment. Source: API RP 8B, Recommended Practice for Procedures for Inspections, Maintenance, Repair and Remanufacture of Hoisting Equipment, Seventh Edition, March 2002 (Reaffirmed: August 2012). Global StandardsMaintenance
Total set of activities performed during the service life of the riser to preserve its function. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global Standards Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global StandardsMaintenance
Combination of all technical and administrative actions, including supervisory actions, intended to retain an item in, or restore it to, a state in which it can perform a required function. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandards Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsMaintenance
Combination of any actions carried out to retain an item in or restore it to, conditions in which it is able to meet the requirements of the relevant specification and perform its required functions. Source: IEC 61892-7, Mobile and fixed offshore units – Electrical installations – Part 7: Hazardous areas. Global Standards Source: IEC 60079-17:2013, Explosive atmospheres – Part 17: Electrical installations inspection and maintenance, Edition 5.0, November 2013. Global Standards Source: IEC 60079-19:2015, Explosive atmospheres – Part 19: Equipment repair, overhaul and reclamation, Edition 3.1, March 2015. Global StandardsMaintenance
Maintenance means minor coating restoration work regularly performed by a ship’s crew using normal shipboard means and tools to maintain “GOOD” or “FAIR” coating conditions. Maintenance delays or slows down the coating deterioration and effects short term steel protection. Source: IMO MSC.1/Circ.1330, Guidelines for maintenance and repair of protective coatings, 11 June 2009, International Maritime Organization. Regulatory GuidanceMaintenance
Set of activities performed during the operating life of a structure to ensure it is fit-for-purpose. Source: ISO 19901-7:2013, Petroleum and natural gas industries – Specific requirements for offshore structures – Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units. Global StandardsMaintenance
Combination of all technical and administrative actions, including supervisory actions, intended to retain an item in, or restore it to, a state in which it can perform a required function Note 1 to entry: There are two basic categories of maintenance: corrective maintenance done after a failure has occurred and preventive maintenance (testing, inspection, condition monitoring, periodic) done before a failure has occurred. See also ISO 14224[15], 9.6. Note 2 to entry: Maintenance activities of either preventive or corrective maintenance category type, is shown in ISO 14224:2006[15], Table B.5. [SOURCE: ISO 14224] Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global StandardsMaintenance
Maintenance means the combination of all technical, administrative and managerial actions during the life cycle of a facility or parts thereof, required to retain it in or restore it to a state in which it can perform the intended functions. Facility or parts thereof includes temporary equipment and third party equipment also. Life cycle include periods in which the facility or parts thereof are temporarily or permanently shut down. Maintenance encompasses activities such as monitoring, inspection, testing, repair and housekeeping. Source: Guidance Notes on Petroleum and Natural Gas (Safety in Offshore Operations) Rules, 2008, Oil Industry Safety Directorate (India), 2012. Regulatory GuidanceMaintenance
Maintenance means the combination of all technical, administrative and management measures during the life cycle of a unit intended to keep it in, or restore it to, a state in which it can perform its intended functions, cf. definition 2.1 (with associated terminology) in the NS-EN 13306 standard. Maintenance includes activities such as monitoring, inspection, testing, trial and repair, and keeping things tidy. Source: Guidelines Regarding the Activities Regulations, Norway, updated December 2012. Regulatory GuidanceMaintenance
Maintenance effectiveness as mentioned in the first subsection, means the ratio between the requirements stipulated for performance and technical condition and the actual results. Source: Guidelines Regarding the Activities Regulations, Norway, updated December 2012. Regulatory GuidanceMaintenance
Maintenance means the combination of all technical, administrative and managerial measures during the life cycle of a unit that are intended to maintain the unit in, or restore it to, a state in which it can perform the intended functions, cf. definition 2.1 (with associated terminology) in the NS-EN 13306 standard. Maintenance includes activities such as monitoring, inspection, testing and repair, and keeping things tidy. Source: Guidelines Regarding the Technical and Operational Regulations, Norway, updated December 2012. Regulatory GuidanceMaintainable Item
Definition(s)
Maintainable Item
Item that constitutes a part or an assembly of parts that is normally the lowest level in the equipment hierarchy during maintenance. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsMaintainable Item
Item that constitutes a part, or an assembly of parts, that is normally the lowest level in the equipment hierarchy during maintenance. See ISO 14224:2006, Annex A, for examples of maintainable items for a variety of equipment. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsLogistic Delay
Definition(s)
Logistic Delay
That accumulated time during which maintenance cannot be carried out due to the necessity to acquire maintenance resources, excluding any administrative delay. NOTE Logistic delays can be due to, for example, travelling to unattended installations, pending arrival of spare parts, specialist, test equipment and information, and delays due to unsuitable environmental conditions (e.g. waiting on weather). Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsLogistic Delay
Accumulated time during which maintenance cannot be carried out due to the necessity to acquire maintenance resources, excluding any administrative delay. NOTE Logistic delays can be due to, for example, travelling to unattended installations; pending arrival of spare parts, specialist, test equipment and information; or delays due to unsuitable environmental conditions (e.g. waiting on weather). Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsItem
Definition(s)
Item
Any part, component, device, subsystem, functional unit, equipment or system that can be individually considered. NOTE In this International Standard, the common term “item” is used on all taxonomy levels 6 to 9 in Figure 3. See also 3.30, which defines a specific item level. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsItem
Any part, component, device, subsystem, functional unit, equipment or system that can be individually considered. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsItem
question or specimen that appears on an examination . Source: ISO/IEC TS 17027:2014, Conformity assessment – Vocabulary related to competence of persons used for certification of persons, Global StandardsIndenture Level
Definition(s)
Indenture Level
Level of subdivision of an item from the point of view of maintenance action. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsIncipient Failure
Definition(s)https://www.iadclexicon.org/wp-admin/post.php?post=4378&action=edit
Incipient Failure
Imperfection in the state or condition of an item so that a degraded or critical failure might (or might not) eventually be the expected result if corrective actions are not taken. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsIdle Time
Definition(s)
Idle Time
Part of the up time that an item is not operating. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsHidden Failure
Definition(s)
Hidden Failure
Hidden failure means a failure that is not immediately evident to operations or maintenance personnel and has the potential for failure of equipment to perform an on-demand function, such as protective functions in power plants and switchboards, standby equipment, backup power supplies or lack of capacity or performance.
Source: IMO MSC.1/Circ.1580, GUIDELINES FOR VESSELS AND UNITS WITH DYNAMIC POSITIONING (DP) SYSTEMS, 16 June 2017, International Maritime Organization. Regulatory GuidanceHidden Failure
A failure that is not immediately evident to operations or maintenance personnel and has the potential for failure of equipment to perform an on-demand function, such as protective functions in power plants and switchboards, standby equipment, backup power supplies or lack of capacity or performance.
Source: IMO MSC.1/Circ.1580, GUIDELINES FOR VESSELS AND UNITS WITH DYNAMIC POSITIONING (DP) SYSTEMS, 16 June 2017, International Maritime Organization. Regulatory GuidanceHidden Failure
Covert failure Dormant failure Unrevealed failure Undetected failure failure which is not immediately evident to operations and maintenance personnel- Note: 1 to entry: Hidden failures do not show themselves when they occur. The occurrence of a hidden failure gives a latent fault which may be revealed by specific tests (e.g. periodic tests) or by the failure of the item to performi ts function when required.
- Note: 2 to entry: The repair of hidden failures cannot begin as long as they have not been detected. The unknown times spent between the failures and their detections belong to the MTTRes.
Hidden Failure
Failure that is not immediately evident to operations and maintenance personnel. NOTE Equipment that fails to perform an “on demand” function falls into this category. It is necessary that such failures be detected to be revealed. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsGeneric Reliability Data
Definition(s)
Generic Reliability Data
Reliability data covering families of similar equipment. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsGeneric Reliability Data
reliability data covering families of similar equipment Note 1 to entry: See ISO 14224[15] for further details on equipment boundaries and equipment taxonomies that define these families of equipment within the petroleum, petrochemical and natural gas industries. Note 2 to entry: Plant-specific data on specific equipment could be part of generic reliability databases, but could differ a lot from generic data and should not be mixed with those. [SOURCE: ISO 14224] Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global StandardsFault
Definition(s)
Fault
Abnormal, undesirable state of a system element induced by the presence of an improper command or absence of a proper one, or by a failure- Note 1 to entry: All failures cause faults; not all faults are caused by failure.
- Note 2 to entry: System elements can include, for example, an entire subsystem, an assembly, or a component.
Fault
State of an item characterized by inability to perform a required function, excluding such inability during preventive maintenance or other planned actions, or due to lack of external resources. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsFault
State of an item characterized by inability to perform a required function, excluding the inability during preventive maintenance or other planned actions, or due to lack of external resources. NOTE A fault is often a result of a failure of the item itself but the state can exist without a failure. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsFault
inability to perform as required- Note 1 to entry: A fault of an item is a state, as distinct from a failure of an item which is an event (see Figure 8).
- Note 2 to entry: A fault of an item may result from a failure of the item or from a deficiency in an earlier stage of
- the life cycle, such as specification, design, manufacture or maintenance.
- Note 3 to entry: Qualifying terms may be used to indicate the cause of a fault, such as specification, design,
- manufacture, maintenance or misuse.
- Note 4 to entry: Inability to perform due to preventive maintenance, other planned actions, or lack of external
- resources does not constitute a fault.
- Note 5 to entry: Figure 8 illustrate the relationship between the concepts of failure and fault:
— The Failure x occurs at stage 1 and leads to the state Fault x which is not detected.
— from stage 2 point of view Fault x is a pre-existing fault.
— The Failure y occurs at stage 2 and lead to the state Faults x,y which is not detected.
— From stage 3 point of view Fault x,y is a pre-existing fault.
— and so on.
[SOURCE: IEC 60050 −191]
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards
Failure on Demand
Definition(s)
Failure on Demand
Failure occurring immediately when the item is solicited to start (e.g. stand-by emergency equipment). NOTE See also Clause C.6. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsNon-Refrigerated Tank
Definition(s)
Non-Refrigerated Tank
Container that stores material in a liquid state without the aid of refrigeration, either by evaporation of the tank contents or by a circulating refrigeration system. NOTE Generally, the storage temperature is close to, or higher than, ambient temperature. Source: API STD 2000, Venting Atmospheric and Low-pressure Storage Tanks, Sixth Edition, November 2009. Global StandardsFailure Mode
Definition(s)
Failure Mode
Effect by which a failure is observed on the failed item. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global StandardsFailure Mode
Effect by which a failure is observed on the failed item. NOTE: See also B.2.6. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsFailure Mode
Effect by which a failure is observed on the failed item. NOTE Failure-mode codes are defined for some equipment classes in ISO 14224:2006, B.2.6. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsFracture Pressure
Definition(s)
Fracture Pressure
Force applied to the surface of a body divided by the original area of that surface. Source: API TR 5C3, Technical Report on Equations and Calculations for Casing, Tubing, and Line Pipe Used as Casing or Tubing; and Performance Properties Tables for Casing and Tubing, Upstream Segment, First Edition, December 2008. Global StandardsFailure Mechanism
Definition(s)
Failure Mechanism
Physical, chemical or other process that leads to a failure. NOTE See also B.2.2. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. GlobalStandardsFailure Data
Definition(s)
Failure Data
Specific equipment unit within an equipment class as defined by its boundary (e.g. one pump). Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsFailure Data
Data characterizing the occurrence of a failure event. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsFailure Cause or Root Cause
Definition(s)
Failure Cause or Root Cause
Circumstances associated with design, manufacture, installation, use and maintenance that have led to a failure. NOTE See also B.2.3. Source: API STD 689, Collection and Exchange of Reliability and Maintenance Data for Equipment, First Edition, July 2007. Global StandardsFailure Cause
Circumstances during design, manufacture or use that have led to a failure. NOTE Generic failure cause codes applicable for equipment failures are defined in ISO 14224:2006, B.2.3. Source: ISO 20815:2008, Petroleum, petrochemical and natural gas industries – Production assurance and reliability management. Global StandardsFailure
Definition(s)
Failure
Loss of structural integrity and/or transmission of fluid leakage through the wall of a component or a joint.Source: ISO 14692-1:2017, Petroleum and natural gas industries — Glass-reinforced plastics (GRP) piping — Part 1: Vocabulary, symbols, applications and materials, Second Edition, August 2017. Global Standards
Failure
An occurrence in a component or system that causes one or both of the following effects:- loss of component or system function
- deterioration of functional capability to such an extent that the safety of the vessel, personnel or environment protection is significantly reduced.
Failure
Failure means an occurrence in a component or system that causes one or both of the following effects:- loss of component or system function; and/or
- deterioration of functional capability to such an extent that the safety of the vessel, personnel or environment protection is significantly reduced.
Failure
Loss of ability to perform as required. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global StandardsFailure
The inability of a system or component to perform its required functions within specified performance requirements. From: NCSD Glossary. Source: NICCS™ Portal Cybersecurity Lexicon, National Initiative for Cybersecurity Careers and Studies (https://niccs.us-cert.gov/glossary) as of 11 November 2015, Global StandardsFailure
Loss of ability to perform as required Note 1 to entry: A failure of an item is an event, as distinct from a fault of an item, which is a state (see Figure 8). [SOURCE: IEC 60050 −191]
Source: ISO/TR 12489:2013(E) Reliability modelling and calculation of safety systems. Global Standards
Failure
Event causing an undesirable condition, e.g. loss of component or system function, or deterioration of functional capability to such an extent that the safety of the unit, personnel or environment is significantly reduced.- NOTE: Examples are structural failure (excessive yielding, buckling, rupture, leakage) or operational limitations (excessive riser tensioner stroke).
Failure
Any equipment condition that prevents it from performing to the requirements of the functional specification. Source: API SPEC 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October 2005 (Reaffirmed June 2012). Global StandardsFailure
Event causing an undesirable condition, e.g. loss of component or system function, or deterioration of functional capability to such an extent that the safety of the unit, personnel or environment is significantly reduced.- EXAMPLE Structural failure (excessive yielding, buckling, rupture, leakage) or operational limitations (slick joint protection length, clearance).
Failure
Improper performance of a device or equipment that prevents completion of its design function. Source: API RP 7G-2, Recommended Practice for Inspection and Classification of Used Drill Stem Elements, First Edition, August 2009. Global Standards Source: API RP 7G, Recommended Practice for Drill Stem Design and Operating Limits, Upstream Segment, Sixteenth Edition, August 1998 (Addendum 2: September 2009). Global StandardsFailure
Termination of the ability of an item to perform a required function.- NOTE: 1 After the failure, the item has a fault.
- NOTE: 2 “Failure” is an event, as distinguished from a “fault,” which is a state.
- NOTE: 3 This concept as defined does not apply to items consisting of software only.
- NOTE: 4 See also Table B.1 and Clauses F.2 and F.3.