The Manufacturer prpares under his responsibility, the Design Report(consisting in design drawing and design calculations, based upon the UDS(User's Design Specification). RPE (Registered Professional Engineer) certifies the design report at Manufacturer's responsibility, to be in accordance with the requirements of the UDS the Code of construction (Sect.VIII Div.2 in our case) and good engineering practice. He will not certify the WPS/PQR. The UDS as well shall be certified by an RPE, at User's responsibility, the minimum content of the UDS is specified in AG-301. WPS's are prepared by the Manufacturer who shall also provide to certify supporting PQR's. In ASME design process there is no other responsibility for the Owner than to provide UDS and have it certified by the RPE.
The AI has the responsibility to verify all process i.e.
He shall verify: UDS, Design Report, WPS/PQR are in accordance with the Code. As a matter of liability the AI does not approve or certify these documents, but when signing the MDR issued by the Manufacturer he signs the certificate of Shop Inspection with the wording..."that at the best of my knowledge and belief, the Manuffacturer has constructed this pressure vessel in accorddance with ASME Code Sect.VIII Div.1". The AI has the duty to ensure that all construction (As per Note 1 of the Foreword, construction is an all inclusive term comprising materials, design, fabrication, examination, inspections, testing,certification, and pressure relief) is in accordance with the Code. Among all he shall verify WPS are duly qualified in accordance with the Code, but he is not required to be a design engineer, not a NDE specialist nor a welding engineer. However he is required to know the Code requirements for all these fields.
Mutual responsibilities are clearly established in Art. G-3 of Sect.VIII Div.2. Mauro