Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Moderate Galling
Definition(s)
Moderate Galling
Galling that can be repaired by the use of fine files and abrasive paper. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global StandardsLight Galling
Definition(s)
Light Galling
Galling that can be repaired by the use of abrasive paper. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global StandardsFailure Load
Definition(s)
Failure Load
Load at which the pipe body or connection will fail catastrophically as in an axial separation, a rupture, large permanent deformation (e.g. buckling or collapse) or massive loss of sealing integrity. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global StandardsConnection
Definition(s)
Connection
Assembly consisting of either two pins and a coupling or one pin and an integral box. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global StandardsConnection
Threaded assembly of tubular components. Source: API SPEC 5CT, Specification for Casing and Tubing, Upstream Segment, Ninth Edition, July 2011 (Errata September 2012). Global StandardsAxial-Pressure Load Diagram
Definition(s)
Axial-Pressure Load Diagram
Plot of pressure versus axial load showing pipe and/or connection test load envelope or limit load extremes. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global StandardsGassy System
Definition(s)
Gassy System
Gassy systems are those in which the unwanted reaction produces non-condensable products and the rate of temperature rise is not tempered by boiling liquid. Gassy systems can be either liquid-phase decompositions or vapour-phase reactions. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsAmbient Temperature
Definition(s)
Ambient Temperature
Prevailing temperature at test site.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global StandardsAmbient Temperature
Actual room temperature in the test lab with no residual heat remaining in test specimens from previous thermal tests. Source: API RP 5C5, Recommended Practice on Procedures for Testing Casing and Tubing Connections, Third Edition, July 2003 (Reaffirmed August 2010). Global StandardsAmbient Temperature
Temperature of the surroundings.. Source: IADC UBO / MPD Glossary, December 2011. Global StandardsTempered System
Definition(s)
Tempered System
Tempered systems are those in which the unwanted reaction produces condensable products and the rate of temperature rise is tempered by liquid boiling at system pressure. Typically, tempered systems are liquid-phase reactions in which a reactant (or solvent) is a major portion of the reactor contents. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsUtility Tip or Pipe-Flare Tip
Definition(s)
Utility Tip or Pipe-Flare Tip
The simplest flare-tip design is commonly referred to as a utility or pipe-flare tip and can consist of little more than a piece of pipe fitted with a flame retention device for flame stability at higher exit velocities (the upper portion is typically stainless steel to endure the high flame temperatures) and a pilot for gas ignition. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsVolumetric Heating
Definition(s)
Volumetric Heating
On the other hand, reactive systems in which an external fire can result in an exothermic reaction are subject to boiling throughout the volume of the vessel due to heat evolved from the reaction. This is commonly referred to as volumetric heating, which results in more liquid-swell than wall-heating and, thus, increases the potential for longer-duration two-phase relief. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsWall-Heating
Definition(s)
Wall-Heating
In non-reactive systems subjected to an external fire, boiling occurs at or near the walls of the vessel, commonly referred to as wall-heating. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsBase of a Pool Fire
Definition(s)
Base of a Pool Fire
The term “base of a pool fire” usually refers to ground level but could be at any level at which a substantial spill or pool fire could be sustained. Various classes of vessels are operated only partially full. Table 5 gives recommended portions of liquid inventory for use in calculations. Wetted surfaces higher than 7,6 m (25 ft) are normally excluded because pool fire flames are not likely to impinge for long durations above this height. Also, vessel heads protected by support skirts with limited ventilation are normally not included when determining wetted area. The user shall specify whether to include the wetted surface area of connected piping in the wetted area calculation. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsSafety Instrumented System
Definition(s)
Safety Instrumented System
System composed of sensors, logic solvers, and final control elements for the purpose of taking the process to a safe state when predetermined conditions are met.- NOTE Other terms commonly used for a SIS include emergency shutdown system (ESD, ESS), safety shutdown system (SSD), and safety interlock system (see E.3.3.1).
Safety Instrumented System
ISA S84.01 defines a safety instrumented system as a “system composed of sensors, logic solvers, and final control elements for the purpose of taking the process to a safe state when predetermined conditions are violated. Other terms commonly used include emergency shutdown system (ESD, ESS), safety shutdown system (SSD), and safety interlock system.” HIPS also fit the definition of a safety instrumented system. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsSafety Instrumented System
System used to implement one or more safety-instrumented functions [2].- Note: A safety-instrumented system is composed of any combination of sensor(s), logic solver(s), and actuator(s).
Windshield
Definition(s)
Windshield
Device used to protect the downwind side of an elevated flare burner from direct flame impingement.- NOTE: Windshields are also integral to the design of pilots to avoid flame-outs due to high winds.
Windshield
Device used to protect the outside of a flare burner from direct flame impingement.- NOTE: The windshield is so named because external flame impingement occurs on the downwind side of an elevated flare burner.
Vent Stack
Definition(s)
Vent Stack
Elevated vertical termination of a disposal system that discharges vapours into the atmosphere without combustion or conversion of the relieved fluid. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsVent Header
Definition(s)
Vent Header
Piping system that collects and delivers the relief gases to the vent stack. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsVelocity Seal
Definition(s)
Velocity Seal
Dry vapor seal based on a flow restriction that minimizes the required purge gas needed to protect against air infiltration into the flare burner exit.
Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global StandardsVelocity Seal
Dry vapour seal that minimizes the required purge gas needed to protect against air infiltration into the flare burner exit. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsVapour Depressuring System
Definition(s)
Vapour Depressuring System
Protective arrangement of valves and piping intended to provide for rapid reduction of pressure in equipment by releasing vapours. NOTE The actuation of the system can be automatic or manual. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsSuperimposed Back Pressure
Definition(s)
Superimposed Back Pressure
Static pressure that exists at the outlet of a pressure-relief device at the time the device is required to operate. NOTE It is the result of pressure in the discharge system coming from other sources and can be constant or variable. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsStorage Tank or Storage Vessel
Definition(s)
Storage Tank or Storage Vessel
Fixed tank or vessel that is not part of the processing unit in petrochemical facilities, refineries, gas plants, oil and gas production facilities, and other facilities. cf. process tank (3.57). NOTE These tanks or vessels are often located in tank farms. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsStoichiometric Air
Definition(s)
Stoichiometric Air
Chemically correct ratio of fuel to air capable of perfect combustion with no unused fuel or air. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsStaged Flare
Definition(s)
Staged Flare
Group of two or more flares or burners that are controlled so that the number of flares or burners in operation is proportional to the relief gas flow. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsShear Pin Device
Definition(s)
Shear Pin Device
Non-reclosing pressure-relief device actuated by static differential or static inlet pressure and designed to function by the shearing of a load-carrying member that supports a pressure-containing member. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsSafety Relief Valve
Definition(s)
Safety Relief Valve
Spring-loaded pressure-relief valve that can be used as either a safety valve or a relief valve depending on the application. Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsSafety-Integrity Level (SIL)
Definition(s)
Safety Integrity Level
Discrete integrity level of a safety instrumented function in a safety instrumented system.- NOTE: SILs are categorized in terms of probability of failure; see Annex E.
Safety-Integrity Level (SIL)
Discrete integrity level of a safety instrumented function in a safety instrumented system. NOTE SILs are categorized in terms of probability of failure; see Annex E. Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global StandardsSafety-Integrity Level (SIL)
discrete level (one out of four) for specifying the safety integrity requirements of the safety instrumented functions to be allocated to the safety instrumented systems Note 1 to entry: Safety integrity level 4 is related to the highest level of safety integrity; safety integrity level 1 has the lowest. Note 2 to entry: The safety integrity level is a requirement about a safety instrumented function. The higher the safety integrity level, the higher the probability that the required safety instrumented function (SIF) will be carried out upon a real demand. Note 3 to entry: This term differs from the definition in IEC 61508–4[2] t o r eflect d ifferences i n p rocess sector terminology. Source: ISO/TR 12489:2013(E), Global StandardsYoke Magnetization
Definition(s)
Yoke Magnetization
Magnetic field induced in OCTG, or in an area of a OCTG, by means of an external electromagnet shaped like a yoke. Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global StandardsRupture-Disk Device
Definition(s)
Rupture-Disk Device
Nonreclosing pressure-relief device actuated by static differential pressure between the inlet and outlet of the device and designed to function by the bursting of a rupture disk.- NOTE: A rupture disk device includes a rupture disk and a rupture disk holder.
Rupture-Disk Device
Non-reclosing pressure-relief device actuated by static differential pressure between the inlet and outlet of the device and designed to function by the bursting of a rupture disk.- NOTE:1 A rupture disk device includes a rupture disk and a rupture disk holder.
- NOTE: 2 In ISO 4126-2, this is termed a bursting-disc safety device.