False Call: An indication
from an inspection that is classified as an anomaly where no imperfection, defect,
or critical defect actually exists.
Faraday (F): Quantity
of electric charge carried by one mole of singly charged atoms, i.e. 96,487
Fatigue: The phenomenon
leading to fracture of a material under repeated or fluctuating stresses having
a maximum value less than the tensile strength of the material.
Fatigue Cracks: Progressive
cracking in the base material, weld, or weld zone that is caused by pressure
cycling or oscillatory stresses associated with the operation of a system.
Feature: The presence
of any physical object detected by an in-line inspection tool during the performance
of an inspection run. Features may be anomalies or indications, pipeline valves
and fittings, nearby metallic objects, or other items.
Field signature method (FSM):
Corrosion monitoring technique which provides a measure of the thickness
of the metal from resistance measurements between sets of pins attached to the
surface. A coil surrounding the area produces the magnetic field to induce the
Flash Welded: Distinct
type of electric resistance weld pipe, made from individually rolled plates
formed into cans before being welded.
Flush coupon: Inserted
coupon flush with the surface of the pipe or vessel.
Flux: The (scalar) number
of flux lines crossing a unit area at right angles to the unit area. See magnetic
Flux Density: (1) A measure
of the intensity of magnetization produced by a magnetic field. (2) A vector
quantity representing the number of flux lines crossing a unit area at right
Flux Leakage: The flow
of flux out of a magnetic material, such as the wall of a pipe, into a medium
with lower permeability, such as gas or air.
Fracture Mechanics: A
quantitative analysis for evaluating structural reliability in terms of applied
stress, crack length, and specimen geometry. For the purpose of this report,
the study of the physics of defect initiation and growth in a material.
Fracture Toughness: A
measure of the resistance of a material to defect extension, either slow or
Free Corrosion Potential:
The electric potential that exists in the absence of an applied potential
with corrosion occurring.
Free Surface: A surface
with one side not constrained by adjacent metal, just air.