Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Deadlegs
Definition(s)
Deadlegs
Components of a piping system that normally have little or no significant flow. Some examples include blanked (blinded) branches, lines with normally closed block valves, lines with one end blanked, pressurized dummy support legs, stagnant control valve bypass piping, spare pump piping, level bridles, pressure relieving device inlet and outlet header piping, pump trim bypass lines, high-point vents, sample points, drains, bleeders, and instrument connections. Deadlegs also include piping that is no longer in use but still connected to the process.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsDamage Rate
Definition(s)
Damage Rate
The rate of deterioration other than corrosion, i.e. rate of cracking, rate of HTHA, creep rate, etc.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsCritical Check Valves
Definition(s)
Critical Check Valves
Check valves in piping systems that have been identified as vital to process safety (see 5.13). Critical check valves are those that need to operate reliably in order to avoid the potential for hazardous events or substantial consequences should reverse flow occur.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsCorrosion Barrier
Definition(s)
Corrosion Barrier
The corrosion allowance in FRP equipment typically composed of an inner surface and an interior layer which is specified as necessary to provide the best overall resistance to chemical attack.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsContact Point
Definition(s)
Contact Point
The locations at which a pipe or component rests on or against a support or other object which may increase its susceptibility to external corrosion, fretting, wear or deformation especially as a result of moisture and/or solids collecting at the interface of the pipe and supporting member.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsCondition Monitoring Locations
Definition(s)
Condition Monitoring Locations
Designated areas on piping systems where periodic examinations are conducted in order to assess the condition of the piping. CMLs may contain one or more examination points and utilize multiple inspection techniques that are based on the predicted damage mechanism(s). CMLs can be a single small area on a piping system e.g. a 2 in. diameter spot or plane through a section of a pipe where examination points exist in all four quadrants of the plane.- NOTE: CMLs now include, but are not limited to what were previously called TMLs.
CMB
Definition(s)
CMB
Computerized monitoring button.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsAuxiliary Piping
Definition(s)
Auxiliary Piping
Instrument and machinery piping, typically small-bore secondary process piping that can be isolated from primary piping systems but is normally not isolated. Examples include flush lines, seal oil lines, analyzer lines, balance lines, buffer gas lines, drains, and vents.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsAuthorized Piping Inspector
Definition(s)
Authorized Piping Inspector
An employee of an owner/user organization or authorized inspection agency (3.1.6) who is qualified and certified by examination under the provisions of Section 4 and Annex A and is able to perform the functions specified in API 570 where contracted or directed to do so. An NDE examiner is not required to be an authorized piping inspector. Whenever the term inspector is used in API 570, it refers to an authorized piping inspector.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsApplicable Code
Definition(s)
Applicable Code
The code, code section, or other recognized and generally accepted engineering standard or practice to which the piping system was built or which is deemed by the owner/user or the piping engineer to be most appropriate for the situation, including but not limited to the latest edition of ASME B31.3.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsAlloy Material
Definition(s)
Alloy Material
Any metallic material (including welding filler materials) that contains alloying elements, such as chromium, nickel, or molybdenum, which are intentionally added to enhance mechanical or physical properties and/or corrosion resistance. Alloys may be ferrous or non-ferrous based.- NOTE: Carbon steels are not considered alloys, for purposes of this Code.
Abandoned-in-place
Definition(s)
Abandoned-in-place
Piping system, circuit or contiguous sections thereof meeting all of the following: has been decommissioned with no intention for future use; has been completely de-inventoried/purged of hydrocarbon/chemicals; and is physically disconnected (e.g. air-gapped) from all energy sources and/or other piping/equipment.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsVessel Material(s)
Definition(s)
Vessel Material(s)
Vessel material(s) are defined as material essential to the structural integrity of the vessel.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsTightness Test
Definition(s)
Tightness Test
A pressure test that is conducted on pressure vessels after maintenance or repair activities to indicate that the equipment is leak free and is conducted at a test pressure determined by the owner/user that is not higher than the MAWP.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsSame or Similar Service
Definition(s)
Same or Similar Service
A designation where two or more pressure vessels are installed in parallel, comparable, or identical service and their process and environmental conditions have been consistent over a period of years based on the inspection criteria being assessed such that the damage mechanisms and rates of damage are comparable.- EXAMPLE: 1 Parallel service: A process or part of a process connected in parallel having comparable configuration with analogous and readily recognized similarities.
- EXAMPLE: 2 Identical service: A designation where there is agreement that the configuration, process and operating regime, metallurgy, and environmental conditions are all the same, such that expected degradation characteristics are expected to be the same.
Scanning Nondestructive Examination
Definition(s)
Scanning Nondestructive Examination
Examination methods designed to find the thinnest spot or all defects in a specified area of a pressure vessel such as profile radiography of nozzles, scanning ultrasonic techniques, and/or other suitable nondestructive examination (NDE) techniques that will reveal the scope and extent of localized corrosion or other deterioration.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsOwner/User
Definition(s)
Owner/User
An owner or user of pressure vessels who exercises control over the operation, engineering, inspection, repair, alteration, maintenance, pressure testing, and rerating of those pressure vessels.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsOwner/User
The organization that exercises control over the operation, engineering, inspection, repair, alteration, pressure testing, and rating of the piping systems.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsOverdue Inspection Recommendations
Definition(s)
Overdue Inspection Recommendations
Recommendations for repair or other mechanical integrity purposes for vessels that are still in operation that have not been completed by their documented due dates, which have not been deferred by a documented deferral process. See 6.8.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsOverdue Inspections
Definition(s)
Overdue Inspections
Inspections for in-service vessels that are still in operation that have not been performed by their due dates documented in the inspection plan, which have not been deferred by a documented deferral process. See 6.7.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsOverdue Inspections
Piping inspections for in-service equipment that have not been performed by their established due dates documented in the inspection schedule/plan and that do not have an approved deferral per 7.10. A piping system not currently in operation due to a process outage would not be considered overdue for inspection if its due date coincides with the time it is out-of-service; however, it would be overdue for inspection if it were placed back in-service before being inspected. Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsNonpressure Boundary
Definition(s)
Nonpressure Boundary
Components of the vessel that do not contain the process pressure (e.g. trays, tray rings, distribution piping, baffles, nonstiffening insulation support rings, clips, davits, etc.).Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards
Nonpressure Boundary
Components and attachments of, or the portion of piping that does not contain the process pressure.- EXAMPLE: Clips, shoes, repads, supports, wear plates, nonstiffening insulation support rings, etc.
Minimum design metal temperature/Minimum allowable temperature
Definition(s)
Minimum design metal temperature/Minimum allowable temperature
The lowest permissible metal temperature for a given material at a specified thickness based on its resistance to brittle fracture. In the case of MAT, it may be a single temperature, or an envelope of allowable operating temperatures as a function of pressure. It is generally the minimum temperature at which a significant load can be applied to a pressure vessel as defined in the applicable construction code [e.g. ASME Code, Section VIII, Division 1, Paragraph UG-20(b)]. It might be also obtained through a FFS evaluation. Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsMinimum design metal temperature/Minimum allowable temperature
The lowest permissible metal temperature for a given material at a specified thickness based on its resistance to brittle fracture. In the case of MAT, it may be a single temperature, or an envelope of allowable operating temperatures as a function of pressure. It is generally the minimum temperature at which a significant load can be applied to a piping system as defined in the applicable construction code. It might be also obtained through a Fitness-For-Service evaluation.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsMDMT/MAT
Definition(s)
MDMT/MAT
Minimum design metal temperature/minimum allowable temperature. Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsMDMT/MAT
The lowest permissible metal temperature for a given material at a specified thickness based on its resistance to brittle fracture. In the case of MAT, it may be a single temperature, or an envelope of allowable operating temperatures as a function of pressure. It is generally the minimum temperature at which a significant load can be applied to a pressure vessel as defined in the applicable construction code [e.g. ASME Code, Section VIII, Division 1, Paragraph UG-20(b)]. It might be also obtained through a FFS evaluation. Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsMDMT/MAT
The lowest permissible metal temperature for a given material at a specified thickness based on its resistance to brittle fracture. In the case of MAT, it may be a single temperature, or an envelope of allowable operating temperatures as a function of pressure. It is generally the minimum temperature at which a significant load can be applied to a piping system as defined in the applicable construction code. It might be also obtained through a Fitness-For-Service evaluation.
Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsMAT
Definition(s)
MAT
Minimum allowable temperature. Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsManufacturer’s Data Report
Definition(s)
Manufacturer’s Data Report
A document that contains data and information from the manufacturer of the pressure vessel that certifies that the materials of construction contained in the vessel meet certain material property requirements, tolerances, etc. and are in accordance with specified standards.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsMajor Repair
Definition(s)
Major Repair
Any work not considered an alteration that removes and replaces a major part of the pressure boundary other than a nozzle (e.g. replacing part of the shell or replacing a vessel head). If any of the restorative work results in a change to the design temperature, minimum allowable temperature (MAT), or maximum allowable working pressure (MAWP), the work shall be considered an alteration and the requirements for rerating shall be satisfied.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsIntegrity Operating Window
Definition(s)
Integrity Operating Window
Established limits for process variables (parameters) that can affect the integrity of the equipment if the process operation deviates from the established limits for a predetermined amount of time. See 4.1.4.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsIOW
Definition(s)
IOW
Integrity operating window. Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsIOW
Established limits for process variables (parameters) that can affect the integrity of the equipment if the process operation deviates from the established limits for a predetermined amount of time. See 4.1.4.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards Source: API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping Systems, Fourth Edition, February 2016, with Addendum May 2017. Global StandardsInspection Deferral
Definition(s)
Inspection Deferral
A documented work process using risk assessment to defer an inspection beyond its due date for a specific period of time. See 6.7.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global StandardsInspection Code
Definition(s)
Inspection Code
A reference to the API 510 code.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards