Mechanical integrity inspections during capital projects

Putting off the initial thickness measurements (i.e., baseline) of piping and vessels in a new process unit is both common and problematic. The tendency of owners is to rely on the nominal thickness because the actual original thickness was either not measured or not recorded for calculating corrosion rates after the thickness readings of first wave are taken with the equipment having been in service for some period of time. Consequently, significant errors in calculated corrosion rates may result from variations of thickness allowed by mill tolerance standards during fabrication. Not having the original thickness can either mask potentially hazardous conditions or cause concern where none is really warranted. Involvement of the inspection department in a capital project can significantly improve quality, reduce cost, and ensure compliance. The objectives of this article are to provide: (1) justification for a detailed inspection during capital projects; (2) show effective roles for inspection departments in capital projects; (3) justification for performing vendor surveillance in capital projects; (4) the technical advantages for performing preservice baseline inspections. © 2011 American Institute of Chemical Engineers Process Saf Prog, 2011