Defect types

Minimum depth

Depth sizing accuracy (90%confidence level)

Width sizing accuracy

(90% confidence level)

Length sizing accuracy(90% confidence level)

General metal loss

0.05T (external)

±0.15T

±25mm

±20mm

0.03T(internal)

Pitting

0.08T(external)

±0.15T

±25mm

±15mm

0.04T(internal)

Axial groove

0.08T(external)

-0.2T/0.15T

±25mm

±25mm

0.04T(internal)

Ring groove

0.05T(external)

-0.15T/0.2T

±25mm

±25mm

0.03T(internal)

Diameter scope

6"~48"

Minimum bend radius

1.5D

Maximum deformation

15%D

Axial orientation

±10°

Identifiable pipeline component

Flange, valve, T-joint, bend, coupling, casing pipe, patch, weld

Defect location accuracy（axial）

The accuracy of distance between defect point and welding edge is ±0.2m,the accuracy of nominal distance between upstream welding edge and identified position is ±1%.