Ultrasonic Test (UT) and Die Penetrant Test (DPT)

The NDTs have their own limitations and are not interchangeable for the requirements.

The RT has its limitation regarding sensitivity. This is improved by the UT. However UT has its dead zone so is supplemented by LPI/ MPI.

Our practice is to

- Root layer LPI after back chipping

- UT 100% after welding.

- LPI- 100% after welding

- MPI in certain critical zones

- RT 10% + 100% in certain joints - T, Knot etc.

Hi maraamaram,

Radiography has a limit of up to at least 2 inches. in your case u still can go for it but the sensitivity on your radiographs will most likely be poor.

Considering that this is a pressure vessel it is not a good idea to totaly rely on radiographs that lack a clear definition.

Carry out LPI on the root run after carrying out mechanical cleaning to bare metal.

Carry out the necessary repairs if any and repeat LPI on the subsequent passes up to the capping.

Carry out spot radiography on intersections and random spot shots on plain welds

If internal access to the vessel is possible grind the root run and weld one pass from the inside and carry out LPI.

In short, 100% LPI, spot radiography say 20% radiography and 100% MPI or UT on all nozzle welds and attachments to the shell.

But first its of vital importance to find out to what code or standard the vessel is constructed to. If you do not get to know try API 510-Pressure vessel inspection code.

regards,

maloba.