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API 653 Out-of-Service Inspection Report <br /> for m m m m <br /> J.R. Simplot Inspection <br /> Tank No. 8 August 27-28,2048 <br /> Lathrop, CA Page 5 of 54 <br /> 2.0 SUMMARY, REPAIR RECOMMENDATIONS AND POST- <br /> REPAIR FINDINGS <br /> FOUNDATION: The survey found the tank to be out of level by 0.875 inch. API 653 <br /> calculation for deflection of this tank is 0.403 inch. API maximum deflection permitted for <br /> this tank is calculated to be 0.93 inch. API 653 calculations for differential settlement do <br /> not exceed the allowable (ref. API 653, Para. B.2.2). Settlement should be monitored by <br /> future periodic survey measurements. <br /> The perimeter of the tank bottom has edge settlement up to a 0.625-inch drop over a 2- <br /> foot distance from the shell in the worst area. Per API 653, Appendix B, Figures B-10 <br /> and B-11, the edge settlement does not exceed 75% of the maximum allowable <br /> settlement. Consideration should be given to monitoring this edge settlement during <br /> future inspections. <br /> The tank rests a.raised gravel pad. A concrete apron will be installed around the tank at <br /> this time to replace this gravel pad (per client). <br /> BOTTOM: Magnetic Flux Leakage (MFL) scanning identified two (2) areas of <br /> recordable metal loss with a remaining thickness of 0.240 inch or below. All areas were <br /> the result of soil side metal loss and no recordable internal metal loss was identified. <br /> Nominal bottom plate thickness is 0.375 inch. Patch plates should be fabricated and <br /> installed to repair these areas. Areas to be repaired by patch plates should have <br /> minimum 12-inch x 12-inch x 0.25-inch carbon steel patches installed using approved <br /> welding and NDE procedures per API 653 guidelines. Vacuum Box (LT/BT) testing <br /> should be performed on all weld repairs. <br /> Corrosion rate calculations based on this inspection information and the age of the <br /> bottom (21 years per data from the client) results in a next inspection cycle <br /> recommendation of no more than 10 years if all areas of corrosion resulting in a <br /> remaining thickness less than 0.240 inch are repaired. <br /> Post-Repair Comments: At the time of this post-repair inspection, all areas of recordable <br /> metal loss were properly repaired with suitable size lap__welded_patch plates. These <br /> repairs had Visual VTperformed and were found to be in accel2table condition. <br /> APIRPTNEMOT REV 2 2628030418r.dw 9f2MDG8 10:09 AM <br />