We have a mounded storage tank for LPG with capacity of 4000 m3. And the stiffener ring for the tank was welded with unapproved WPS and PQR. Since the PQR failed in charpy impact test at required MDMT of -46°C.
Stiffener rings are impact testing exempted as per §UCS-68 (c) and §UCS-67 of ASME...