6.3.7.1 For type A independent
tanks and semi-membrane tanks where the design temperature is -20°C
or less, and for type B independent tanks regardless of temperature,
all full penetration butt welds of the shell plating of cargo tanks
should be subjected to 100% radiographic inspection.
6.3.7.1.1 Where the design
temperature is higher than -20°C, all full penetration butt welds
in way of intersections and at least 10% of the remaining full penetration
welds of tank structures should be subjected to radiographic inspection.
6.3.7.1.2 In each case
the remaining tank structure including the welding of stiffeners and
other fittings and attachments should be examined by magnetic particle
or dye penetrant methods as considered necessary by the Administration.
6.3.7.1.3 All test procedures
and acceptance standards should be in accordance with Recognized Standards.
The Administration may accept an approved ultrasonic test procedure
in lieu of radiographic inspection, but may in addition require supplementary
inspection by radiography at selected locations. Further, the Administration
may require ultrasonic testing in addition to normal radiographic
inspection.
6.3.7.2 Inspection of type
C independent tanks and process pressure vessels should be carried
out in accordance with 4.10.9.
6.3.7.3 For integral and
membrane tanks, special weld inspection procedures and acceptance
criteria should be in accordance with Recognized Standards.
6.3.7.4 The inspection and
non-destructive testing of the inner hull or the independent tank
structures supporting internal insulation tanks should take into account
the design criteria given in 4.4.7.
The schedule for inspection and non-destructive testing should be
to the satisfaction of the Administration.
6.3.7.5 Inspection of piping
should be carried out in accordance with the requirements of chapter 5.
6.3.7.6 The secondary barrier
should be radiographed as considered necessary by the Administration.
Where the outer shell of the hull is part of the secondary barrier,
all sheer strake butts and the intersections of all butts and seams
in the side shell should be tested by radiography.