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Galvanic corrosion: Corrosion
due to dissimilar materials being in the presence of an electrolyte.
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Galvanic probe: Basically
a zero resistance ammeter used to measure galvanic coupling across two dissimilar
metals. Typically used for steel and brass in seawater applications and various
atmospheric corrosivity probes..
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Gathering Line: A pipeline
that transports gas from a production facility, e.g. gas well, to a processing
or compressor station prior to entry into the transmission pipeline.
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Gauge Plate/Bend Plate Pig:
A utility pig mounted with a flexible metal plate of a specified diameter
less than the minimum internal diameter of the pipeline. Pipe bore restrictions
less than the plate diameter or short radius bends will permanently deflect
the plate material.
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Gauging Pig: A utility
pig mounted with a flexible metal plate, or plates, of a specified diameter
less than the minimum internal diameter of the pipeline. Pipe bore restrictions
less than the plate diameter or short radius bends will permanently deflect
the plate material.
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Gel Pig: A utility pig
that is composed of a highly viscous gelled liquid, often used for pipeline
cleaning.
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Geographical Information System (GIS):
A computer system capable of assembling, storing, manipulating, and displaying
geographically referenced information.
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Geometry Pig: A configuration
pig designed to record conditions, such as dents, wrinkles, ovality, bend radius
and angle, and occasionally indications of significant internal corrosion, by
sensing the shape of the internal surface of the pipe.
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Girth Weld: Circumferential
weld joining two joints of pipe.
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Girth Weld Cracks: Cracks
in the weld or weld zone of the butt welds that connect sections of pipe.
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Global Positioning System (GPS):
The navigational system utilizing satellite technology to provide a user
an exact position on the earth's surface.
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Gouge: Local damage caused
by mechanical or forceful removal of metal from a local area on the surface
of the pipe that may work harden the pipe and make it more susceptible to cracking.
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Gouging: The process of
creating a zone of mechanical damage that includes cold working, residual stresses,
plastic distortion, and (generally) moved or removed metal.
