Page 96 - Pipeline Pigging Technology

Pigging for flexible pipes

Defects
Geometry Material Cracks & Cracks in Dis-
changes degra- breakage polymer bonding
dation in steel layers
comp.
Method

Thermography X X X X
X-ray and gamma X X X X
radiography
Acoustic methods X X X
Tracing isotopes X X X
Cable-based leak X X X
detection
Magnetic induction X
Eddy current X X
Photogrammetry X
Boroscopes X X X X
Ultrasonic inspection X X X
Holography X X X
Impedence X

Table 2. Relationship between pipe defects and recognition by
various equipment.

RECOMMENDATIONS AND CONCLUSIONS

Flexible pipe is an inhomogeneous structure which because of its compos-
ite construction exhibits a complex behaviour. Due to the roughness of its
internal bore and differences in the mechanical properties of its varying
components, it is essential to gain an appreciation of this new pipeline
technology before an inspection programme can be formulated. Inspection
of flexible pipe is possible and has been previously reported [Neffgen,1988].
A number of specifically-adapted techniques have already been tested and
their applicability is illustrated in Table 2, which also illustrates the relation-
ship between effects caused by the most likely defects and the ability of a NDT

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