My organization recently had a large diameter pipe spool (24") replaced that joins two existing tanks at their flanges. Prior to fabrication, the vendor came to site and took measurements between the existing tank flanges to ensure the spool would be fabricated correctly. Shop drawings were created and the pipe spool was fabbed. In the end, fitup is poor and we're using gaskets to make up gaps.

My question is; in pipe fabrication, is there an industry standard means of measuring between the two tank flanges that a pipe spool fabricator needs to utilize? My thought is to measure squareness by measuring four common spots on each flange to establish length and to check if the flanges are square (parallel to one another), but I am not a fabricator so I don't know best practice.

Also, lidar scanning is not really an option in this case.
Thank you.