M

Definition(s)

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Maintenance, Operational

Any maintenance activity, excluding corrective maintenance, intended to be performed by the operator and required in order for the equipment to serve its intended purpose. Such activities typically include the correcting of zero on a panel instrument, changing charts, record keeping, adding ink, and the like.

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

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Maintenance,Corrective

Any maintenance activity that is not normal in the operation of equipment and requires access to the equipment's interior. Such activities are expected to be performed by a qualified person. Such activities typically include locating causes of faulty performance, replacement of defective components, adjustment of internal controls, and the like.

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

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Minimum Bending Radius

Minimum radius to which the synthetic fiber rope construction can be bent to without damage to any part of the rope construction (including the jacket and filter). Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards

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Mixing Point

Mixing points are locations in a process piping system where two or more streams meet. The difference in streams may be composition, temperature or any other parameter that may cause deterioration and may require additional design considerations, operating limits, inspection and/or process monitoring.

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 Standards

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Minimum Required Thickness

The thickness without corrosion allowance for each component of a piping system based on the appropriate design code calculations and code allowable stress that consider pressure, mechanical and structural loadings.

• NOTE: Alternately, minimum required thicknesses can be reassessed using Fitness-For-Service analysis in accordance with API 579-1/ASME FFS-1.

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 Standards

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Minimum Alert Thickness (flag thickness)

A thickness greater than the minimum required thickness that provides for early warning from which the future service life of the piping is managed through further inspection and remaining life assessment.

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 Standards

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Material Verification Program

A documented quality assurance procedure used to assess metallic alloy materials (including weldments and attachments where specified) to verify conformance with the selected or specified alloy material designated by the owner/user.

• NOTE: This program may include a description of methods for alloy material testing, physical component marking, and program recordkeeping (see API 578).

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 Standards

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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 Standards  

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 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 Standards

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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 Standards

MDMT/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 Standards  

MDMT/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 Standards

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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 Standards

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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 Standards

Definition(s)

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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 Standards

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Mud Cap Drilling

A drilling process that involves maintaining a mud level in the annulus below the surface for hole stability and well control purposes, and no surface back-pressure. In MCD, there are no flow returns to the surface while maintaining mud column on the annular side. There exists several MCD variations, such as PMCD, FMCD etc. MCD is an umbrella term used for FMCD and PMCD.

Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards

Definition(s)

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MCD

Mud Cap Drilling. Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards  

MCD

A drilling process that involves maintaining a mud level in the annulus below the surface for hole stability and well control purposes, and no surface back-pressure. In MCD, there are no flow returns to the surface while maintaining mud column on the annular side. There exists several MCD variations, such as PMCD, FMCD etc. MCD is an umbrella term used for FMCD and PMCD. Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards

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MPD Annular

A device installed in the drilling riser below the RCD to make possible removing and replacing a worn RCD sealing/bearing element while back-pressure is being applied. MPD annular may be used to isolate the RCD during emergencies such as a gas in riser event.

Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards

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Mass Flow Meter

A measuring device that is capable of working with flow streams to measure the mass rate of flow and the density of the fluid stream (e.g., Coriolis Meter). Source: ABS Guide for Classification and Certification of Managed Pressure Drilling Systems, September 2017. Global Standards

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Piping Component

Mechanical element suitable for joining or assembly into a pressure-tight fluid-containing piping system.

• EXAMPLE: Pipe, fittings, flanges, gaskets, bolting, valves, and devices such as expansion joints, flexible joints, pressure hoses, liquid traps, strainers and in-line separators.

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

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Modulated differential scanning calorimetry

Type of DSC (3.2.19) that enables reversible reactions to be distinguished from irreversible processes such as additional polymerization of the resin during the test. 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

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MDSC

Type of DSC (3.2.19) that enables reversible reactions to be distinguished from irreversible processes such as additional polymerization of the resin during the test. 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

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Minor Poisson’s Ratio, Vah

Hoop strain resulting from a stress in the axial direction.

• Note: 1 to entry: GRP pipes will typically contract in the hoop direction when subjected to an axial stress.

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

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Mill Hydrostatic Test

Short-term hydrotest at the mill, or factory, used as a quality control check which is carried out at a pressure above the design pressure.

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

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Megohmmeter

High-voltage instrument used for measuring electrical resistance.

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

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Mechanical Joint

Joint between GRP piping components which can resist thrust from internal pressure and is not made by bonding.

• Note 1 to entry: A mechanical joint typically involves use of proprietary devices.
• Note 2 to entry: A prescribed threaded joint (3.2.98) is a type of mechanical 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

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Matrix

Homogeneous resin or polymer material in which the fibre system is imbedded in a laminar arrangement.

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

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Maximum Pressure Rating

Pressure rating given by the manufacturer in product literature.

• Note: 1 to entry: MPR_xx is the maximum pressure rating at sustained conditions for a 20-year design life at the temperature of xx °C. MPR_xx is the maximum catalogue value published by the manufacturer.

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

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Major Poisson’s Ratio, V_ha

Axial strain resulting from a stress in the hoop direction.

• Note: 1 to entry: GRP pipes will typically contract in the axial direction when subjected to a hoop stress.
• Note: 2 to entry: For GRP pipes wound at a 54° winding angle, the Poisson's ratio will typically be smaller in magnitude than the minor Poisson's ratio (3.2.79).

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

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Mud Logging Module

Modularized facilities that include mud logging room, data acquisition system and display terminal, used to provide mud logging services. Source: ISO 18647:2017, Petroleum and natural gas industries — Modular drilling rigs for offshore fixed platforms, First Edition, August 2017. Global Standards

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Modular Drilling Rig

Modularized facilities for drilling from a fixed offshore platform consisting of drilling equipment set, drilling support, P-tank, cementing, well logging, mud logging and other equipment. Source: ISO 18647:2017, Petroleum and natural gas industries — Modular drilling rigs for offshore fixed platforms, First Edition, August 2017. Global Standards

Definition(s)

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 MDR

Modular Drilling Rig. Source: ISO 18647:2017, Petroleum and natural gas industries — Modular drilling rigs for offshore fixed platforms, First Edition, August 2017. Global Standards  

MDR

Manufacturer's data reports. 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 Standards  

MDR

Modularized facilities for drilling from a fixed offshore platform consisting of drilling equipment set, drilling support, P-tank, cementing, well logging, mud logging and other equipment. Source: ISO 18647:2017, Petroleum and natural gas industries — Modular drilling rigs for offshore fixed platforms, First Edition, August 2017. Global Standards