Glossary
Browse the IADC Lexicon alphabetically or by category. Get comprehensive definitions of drilling industry terms.
Probabilistic Seismic Hazard Analysis
Definition(s)
Probabilistic Seismic Hazard Analysis
Framework permitting the identification, quantification, and rational combination of uncertainties in earthquakes' intensity, location, rate of recurrence, and variations in ground motion characteristics. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsPSHA
Definition(s)
PSHA
Probabilistic seismic hazard analysis. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsPSHA
Framework permitting the identification, quantification, and rational combination of uncertainties in earthquakes' intensity, location, rate of recurrence, and variations in ground motion characteristics. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsMud Volcanoes
Definition(s)
Mud Volcanoes
Diapiric intrusion of plastic clay causing high pressure gas-water seepages which carry mud, fragments of rock (and occasionally oil) to the surface. NOTE The surface expression of a mud volcano is a cone of mud with continuous or intermittent gas escaping through the mud. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsModal Combination
Definition(s)
Modal Combination
Combination of response values associated with each dynamic mode of a structure. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsLiquefaction
Definition(s)
Liquefaction
Fluidity of cohesionless soil due to the increase in pore pressures caused by earthquake action under undrained conditions. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsGround Motions
Definition(s)
Ground Motions
Accelerations, velocities, or displacements of the ground produced by seismic waves radiating away from earthquake sources. NOTE A fixed offshore structure is founded in or on the seabed and consequently only seabed motions are of significance. The term ground motions is used rather than seabed motions for consistency of terminology with seismic design for onshore structures. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsFault Movement
Definition(s)
Fault Movement
Movement occurring on a fault during an earthquake. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsExtreme Level Earthquake
Definition(s)
Extreme Level Earthquake
Earthquake with a severity which the structure should sustain without major damage. NOTE The ELE event is comparable to the extreme environmental event in the design of fixed structures which is described in API 2A-WSD, 22nd Edition and ISO 19903, When exposed to an ELE, a structure is supposed to retain its full capacity for all subsequent conditions. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsEscape and Evacuation Systems
Definition(s)
Escape and Evacuation Systems
Systems provided on a platform to facilitate escape and evacuation in an emergency. NOTE Escape and evacuation systems include passageways, chutes, ladders, life rafts, and helidecks. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsDirectional Combination
Definition(s)
Directional Combination
Combination of response values due to each of the three orthogonal components of an earthquake motion. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsAttenuation
Definition(s)
Attenuation
Decay of seismic waves as they travel from a source to the site under consideration. Source:API RP 2EQ, Seismic Design Procedures and Criteria for Offshore Structures, First Edition, November 2014. Global StandardsAbnormal Level Earthquake
Definition(s)
Abnormal Level Earthquake
Intense earthquake of abnormal severity under the action of which the structure should not suffer complete loss of integrity.- NOTE: The ALE event is comparable to the abnormal event in the design of fixed structures which are described in API 2A-WSD and ISO 19903. When exposed to the ALE, a manned structure is supposed to maintain structural and/or floatation integrity for a sufficient period of time to enable evacuation to take place.
Yarn-on-yarn Abrasion Property
Definition(s)
Yarn-on-yarn Abrasion Property
The average cycles to failure at a designated applied load which the yarn exhibits when tested by the yarn-on-yarn abrasion test method. Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsYarn Elongation
Definition(s)
Yarn Elongation
The average elongation at break from several yarn break tests. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsYarn Creep
Definition(s)
Yarn Creep
The characteristics of the yarn that undergo a time related non-recoverable increase in length when subjected to sustained load. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsYarn Break Strength
Definition(s)
Yarn Break Strength
The average breaking load from several yarn break tests. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsYarn Assembly Checklist
Definition(s)
Yarn Assembly Checklist
A document completed during the yarn assembly process which states the nominal values and records the actual values for each set-up of each step of the process of the yarn. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsYarn
Definition(s)
Yarn
A generic term for a bundle of untwisted or twisted fibers. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsWedged Socket
Definition(s)
Wedged Socket
A termination generally consisting of a tapered socket into which the rope is inserted with separated strands and broomed out yarns and then secured by a tapered wedge-like device set and driven into the center of the yarns. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsTermination Specification
Definition(s)
Termination Specification
A document which completely describes the design of the termination and the process of making that termination, including materials and steps for making or assembling the termination. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsSubrope-to-Rope Efficiency
Definition(s)
Subrope-to-Rope Efficiency
The percentage of the full rope strength compared to the aggregate subrope strength of the assembly. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsStrand Assembly Checklist
Definition(s)
Strand Assembly Checklist
A document completed during the strand assembly process which states the nominal values and records the actual values for each set-up of each step of the process of assembling strands. Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsStrain
Definition(s)
Strain
The ratio of elongation to the gauge length over which the elongation takes place. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsRope Yarn
Definition(s)
Rope Yarn
The largest yarn-like component of a strand generally formed by twisting intermediate yarns together. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsRope Strength Factor
Definition(s)
Rope Strength Factor
The ratio of rope break strength to aggregate yarn strength. Source: API RP 2SM Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, Second Edition, July 2014. Global Standards Source: API RP 2SM, Design, Manufacture, Installation, and Maintenance of Synthetic Fiber Ropes for Offshore Mooring, First Edition, July 2014. Global StandardsRope Stiffness
Definition(s)
Rope Stiffness
rope modulus The ratio of rope stress to strain/the ratio of rope tension to elongation.- NOTE: Stiffness is often preferred as it is difficult to determine the area for a synthetic rope. Often the terms
- dynamic modulus/stiffness and static modulus/stiffness are used. Dynamic refers to modulus/stiffness values
- obtained when the rope is loaded quickly (seconds to minutes) where static refers to modulus/stiffness values
- obtained when the rope is loaded slowly (hours to days).