Doing Dye Penetrant Test on the welding of the nipple of the drain valve [ plug and sealed weld]
after it was hydrotested. Does this practice is acceptable ??
Dye penetrant testing is , probably the cheapest and least reliable test procedure for welding ! In a non pressure vessel (non hazardous content) I see no reason not to use dye, however, UT would be MUCH better. In ANY critical application, I choose UT over dye penetrant.
Dye penetrant is so simple to use and readily available to everyone that in some cases it is NOT used correctly. A contradiction in terms, maybe, but none the less a problem. There are no certifications for operators of dye penetrant.
A note here---It is NOT acceptable to weld on high pressure vessels without proper certification and re-testing under current Cal-OSHA regulations!
hjom,
In my opinion, it is acceptable. I understand that seal welding is carried out after drain the water from your piping system. If you would like to re-hydrostatic test, you should think about draining again...without plug removal...
