API 653 Summary

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FOUNDATION

1. The perimeter of the tank bottom has edge settlement up to a 1.32-inch drop over a 1-foot distance from the shell. The B/R ratio is 1.32 inches per foot, which exceeds the API allowable of 0.37 inch per foot (Ref. API 653, Para. B.3.3). Since the shell-to-bottom joint was examined by Magnetic Particle (MT), Vacuum Box (LT/BT) and Visual Testing (VT) inspection methods and no recordable indications were found, no corrective action is required. The edge settlement should be re-evaluated at the next inspection interval. 2. The perimeter of the tank bottom has edge settlement up to a 4.68-inch drop over a 3.33-foot distance from the shell. The B/R ratio is 1.41 inches per foot, which exceeds the API allowable of 0.37 inch per foot (Ref. API 653, Para. B.3.3). Since the shell-to-bottom joint is coated additional NDE examinations could not be performed. The extent of the settlement warrants foundation repair or a more detailed analysis should be performed. 3. Normally, differential settlement is a good indicator of settlement related to foundation problems. In this instance, the tank rests on a concrete slab with no evidence of cracks or significant misalignment due to original construction (i.e. no cold joint). Since the tank is small in diameter, the short arc distance between settlement readings results in a very small allowable settlement per API 653 calculation. Because this tank is on a stable slab, no corrective action or further evaluation of settlement is necessary at this time. 4. The tank rests on a raised sand pad with an asphalt coating. The asphalt berm has been severely broken up, creating voids around the tank. The grade should be re-worked and these voids should be filled with homogenous material to provide adequate drainage away from the tank to allow for visual inspection of the shell-to-bottom joint area at all times (Ref. API 653, Para. 4.3.1). 5. The concrete ring has severe damage at two (2) locations, Stations 16 ft. and 212 ft. (measured CCW from Manway A). These cracks should be further investigated to determine their depth and the ringwall should be checked as to whether reinforcement is present and as to its condition. The cracks should then be repaired to minimize further degradation of the foundation. 6. The tank is resting on a concrete ringwall foundation. This ringwall has cracks intermittently around the tank. These cracks should be sealed to prevent further degradation of the foundation from moisture penetration corroding the reinforcement or from freeze/thaw cycling further opening these cracks.

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FOUNDATION

7. This ringwall has minor cracks intermittently around the tank. These cracks should be sealed to minimize further degradation of the foundation from moisture penetration corroding the reinforcement or from freeze/thaw cycling further opening these cracks. 8. The tank is resting on a concrete ringwall foundation. This ringwall has hairline cracks intermittently around the tank. The ringwall is coated and this coating has failed. Consideration should be given to recoating the ringwall to minimize further degradation of the foundation from moisture penetration corroding the reinforcement or from freeze/thaw cycling further opening these cracks. 9. The tank is resting on a concrete ringwall foundation. This ringwall has severe spalling and cracks intermittently around the tank. These areas should be repaired and sealed to minimize further degradation of the foundation from moisture penetration corroding the reinforcement or from freeze/thaw cycling further opening these cracks. 10. The grade surrounding the tank does not provide drainage away from the foundation. Vegetation around the foundation and from under tank is heavy. Consideration should be given to re-working the grade to provide adequate drainage away from the tank and to allow for visual inspection of the shell-to-bottom joint area at all times (Ref. API 653, Para. 4.3.1). 11. The grade around the perimeter of the tank has washed away creating voids under the shell and bottom edge projection. This condition should be corrected by the addition of suitable subgrade material to the periphery of the tank and under the shell-to-bottom projection. (Precautions should be taken to avoid placing rock or gravel under the tank since the presence of such material may result in increased underside pitting corrosion). 12. At the time of inspection, the lower 0.5 to 1.0 inch of the shell was covered with rock and soil from Stations 186.0 to 222.0 feet (measured circumferentially CCW from Manway A). This area has active corrosion on the shell and the bottom edge projection. Consideration should be given to re-working this area to provide adequate drainage away from the tank to allow for visual inspection of the shell-to-bottom joint area at all times (Ref. API 653, Para. 4.3.1). This area should be re-coated to minimize further corrosion. 13. There is no moisture barrier in place at the bottom edge projection, allowing water to enter under the tank bottom. A suitable moisture barrier should be installed around the entire tank bottom perimeter.

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BOTTOM

Twenty-eight (28) areas of underside corrosion with a remaining thickness at or below 0.180 inch were found. Seven (7) areas of internal corrosion with a pit depth of 0.070 inch or greater were found. Thirty-four (34) holes were also found as a result of internal corrosion. Patch plates should be fabricated and installed by lap welding. Areas to be repaired should be ground smooth and minimum 12-inch x 0.25inch carbon steel patch plates should be installed over each area using approved weld procedures per API 653 guidelines. Vacuum Box Testing (LT/BT) should be performed on the patch plate weld seams. Consideration should be given to improving top side or underside corrosion protection by application of a coating or installation of a cathodic protection system. 14. Exceptions to this are the three (3) areas of underside corrosion and one (1) area of internal corrosion that lie in the critical zone. The recommended repair for this widely scattered pitting (Ref. API 653, Para. 7.9.1.1) should be by welding bottom patches (Revision to API 653, per Addendum 3, now allows bottom patches in the critical zone Ref. Para. 7.10.1.2 and Fig. 7-5). 15. Exceptions to this are the seven (7) holes and one hundred one (101) areas of internal plate and weld corrosion that lie in the critical zone. Due to the combination of internal corrosion and severe corrosion of the bottom-to-shell weld, the recommended repair would be to install new sketch plates around the entire base of the tank in accordance with API 653 guidelines. Due to the extent of the corrosion found in these areas, weld repairs within the critical zone would exceed API 653 guidelines. Consideration should be given to improving top side or underside corrosion protection by application of a coating or installation of a cathodic protection system. 16. The MFE floorscan revealed no areas of significant metal loss. There is general internal corrosion throughout the tank averaging 0.010 to 0.020 inch, with a maximum depth of 0.040 inch. Based on these findings, the next internal inspection should be conducted within 20 years if no repairs are made or no coatings are applied to the bottom at this time. 17. The bottom is coated with an irregular fiberglass coating. Due to this irregular coating, the MFE and UT examination of the bottom could not be performed. The coating is in acceptable condition. Nominal bottom thickness is 0.250 inch, which was verified at the bottom edge projection outside. 18. The MFE and visual inspection of the tank bottom revealed over one thousand (1,000) areas of internal pitting and severe general internal corrosion. The shell-to-bottom weld has severe corrosion over 75% of

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BOTTOM

the total perimeter. There are several sketch plates that have pitting within the critical zone that cannot be considered widely scattered. This tank is a good candidate for a complete bottom replacement. 19. Corrosion rate calculations per API Standard 653, Para. 2.4.7 regarding minimum tank bottom plate thickness based on the original date of construction and the results of the inspection measurements by ultrasonic readings, taken at random locations and at several areas of one square foot automated scans, indicate a future service cycle recommendation of 20 years is possible but it should be noted that areas of the floor not inspected (especially bottom plate underside areas not visible) could have actual corrosion rates which would exceed those calculated from the information taken. On that basis, consideration should be given to planning at least one additional internal inspection at an intermediate interval to the 20-year calculated cycle to confirm these corrosion rates or to establish new ones from more complete or more recent data. 20. Based on these findings, the next internal inspection should be conducted within 20 years subject to intermediate confirmation of continuing coating integrity (tank should be cleaned and inspected for evidence of internal corrosion or paint failure). 21. There are numerous pre-existing lap welded patch plates in the critical zone which do not intersect the shell-to-bottom weld at ninety degrees as recommended by API 653. This can result in areas of increased stress concentration and possible accelerated corrosion. Visual inspection did not identify any such corrosion present. Additional inspection by Magnetic Particle (MT) methods indicated no identifiable defects. 22. The roof support columns are welded to bearing plates that are welded to the bottom. This detail results in the roof being rigidly connected to the bottom. This practice is not recommended and these details should be changed at the time the new bottom is installed. 23. The roof support pipe columns are welded to their base plates and these base plates are not seal welded to the bottom. Consideration should be given to changing this detail by detaching the pipe columns from their base plates, installing lateral clips and seal welding the base plates to the bottom. 24. The center roof support column clips do not provide adequate lateral restraint from movement. Lateral clips should be installed to restrict lateral movement in all directions.

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BOTTOM

25. The existing bottom edge projection from Stations 273.0 to 286.0 feet is less than the 3/8 inch allowable per API 653, Para. 2.4.7.7. The sketch plates affected by this condition should be replaced with material having sufficient edge projection the next time this tank is scheduled for major repairs to the shell or when a hydrotest is required due to other repairs. 26. Eight (8) of the sixteen (16) floating roof striker plates exhibit numerous areas of weld corrosion and product weeping from beneath. These conditions should be repaired prior to returning the tank to service. 27. There are several areas of evidence of leakage from the bottom around the tank. This riveted bottom is lined with a heavy irregular fiberglass coating that extends up the shell. The lower six (6) inches of the shell and rivets on the outside of the tank are severely corroded under layers of epoxy coating. Due to the heavy irregular bottom coating, the MFE and ultrasonic examination of the bottom plates could not be performed. Visual (VT) inspection of the shell-to-bottom connection was also impossible due to this heavy coating. This bottom should be replaced with a new lap welded bottom installed through slots in the shell cut above the corrosion or the coating could be removed to allow for more complete bottom inspection. 28. Two leak paths were found on the bottom, one located on a plate-to-plate lap weld and the other on the center roof support bearing plate seal weld. These areas should be repaired in accordance with API 653 prior to returning the tank to service. 29. The ladder/gauge pole assembly is welded to its bearing plate and this bearing plate is not seal welded to the bottom. The bearing plate is restricted from movement with lateral clips welded to the bottom. A better detail would be to seal weld the bearing plate to the bottom, detach the ladder from the plate and relocate the lateral clips to restrict the ladder/gauge pole movement. 30. There are two (2) pre-existing lap welded patch plates in the critical zone on Plate 105 which do not intersect the shell-to-bottom weld at ninety degrees as recommended by API 653. This can result in areas of increased stress concentration and possible accelerated corrosion. Visual (VT) inspection did not identify any such corrosion present. Additional inspection by Magnetic Particle (MT) methods indicated no identifiable defects. 31. Two leak paths were found in the shell-to-bottom weld on Plates 3 and 23. These leak paths should be repaired in accordance with API 653. The visual examination of the shell-to-bottom joint was limited due to poor cleaning.

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BOTTOM

32. The tank currently has four (4) water draw nozzles with no draw-off sumps. Consideration should be given to installing draw-off sumps in the bottom at these locations so that water may be more effectively removed from the tank. The draw-off sumps should be installed in accordance with API 650 and 653 guidelines (Ref. API 650, Figure 318 and Table 3-16). 33. The tank currently does not have cathodic protection. Consideration should be given to installing a cathodic protection system as a method of achieving better corrosion control (Ref. API 651, Cathodic Protection of Aboveground Petroleum Storage Tanks). 34. The center roof support column lateral clips do not provide adequate restraint from movement. Consideration should be given to modifying the clips so that lateral movement will be restrained. 35. The shell-to-bottom weld has severe crevice corrosion and the sketch plates have deformed due to the edge settlement around the perimeter of the tank. Note the examination of the sketch plates was limited due to the edge settlement. The shell-to-bottom weld is covered with an epoxy coating thus preventing a complete examination. Consideration should be given to replacing the sketch plates to correct these conditions or the coating should be removed to allow for more complete inspection of these areas. 36. The roof support pipe columns do not have drainage holes at their base. Drainage holes should be installed at the base of these pipe columns to provide positive drainage. 37. The bottom edge projection has severe corrosion around the entire perimeter of the tank with areas of complete deterioration. This corrosion does not appear to extend beyond the shell-to-bottom weld. Due to severe internal corrosion within the critical zone and edge settlement, the recommended repair would be to install a new annular plate ring around the entire base of the tank in accordance with API 653. Consideration should be given to improving the top side or underside corrosion protection by application of a coating or by installation of a cathodic protection system.

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SHELL

The tank does not have a ground system. Consideration should be given to whether or not the tank is adequately grounded (Ref. API RP 2003 for additional guidance). 38. There are two (2) vertical welds that exhibit product leakage located on Course 4 at Station 142.9 feet and on Course 3 at Station 173.4 feet (measured circumferentially CCW from Manway A). Further investigation of these two (2) areas should be performed to identify the cause of the leakage. 39. The shell has a band of corrosion up to six (6) inches from the shell-tobottom weld intermittently around the entire tank. The maximum depth of this corrosion measured approximately 0.4 inch. Consideration should be given to slotting the shell above this band of corrosion when the tank bottom is replaced. 40. There are ten (10) holes equally spaced around the shell 27 inches below the top of the tank. The holes are 1.5 inches in diameter and were installed to provide visual confirmation of tank overfilling. A mechanical shield and screen should be installed over these openings to prevent water and birds from entering the tank. 41. The shell has thirty (30) vents with rain hoods evenly spaced around the top course. These vents do not have screens covering them to prevent birds from entering the tank. The installation of screening over these vents should be performed. 42. There are two (2) riveted door sheets located at Station 38.1 and Station 226.9 feet (measured circumferentially CCW from Manway A). There is evidence of leakage at both locations on the outside of the tank. This riveted door sheet is an API Appendix A shell connection which is not normally used in tanks built to more current industry practices. Consideration should be given to replacing this shell connection with an API flush-type cleanout connection. 43. There are four (4) holes equally spaced around the shell 24 inches below the top of the tank. The holes are 1.5 inches in diameter and were installed to provide visual confirmation of tank overfilling. Consideration should be given installing a mechanical shield and screen to prevent water and birds from entering the tank. 44. Shell thickness calculations indicate the safe fill height of 48.00 feet can be utilized with any product specific gravity up to 0.98. The hydrostatic test height, or storage of any product with a specific gravity between 0.98 and 1.0, should be restricted to between 48.00 and 47.18 feet, respectively (Ref. API 653, Para. 2.3.3.1).

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SHELL

45. There is a riveted door sheet located at Station 121.5 feet (measured circumferentially CCW from Manway A). This riveted door sheet is an API Appendix A shell connection which is not normally used in tanks built to more current industry practices. Consideration should be given to replacing this shell connection with an API flush-type cleanout connection if there is long-term concern about the possibility of leaking rivets. 46. Item K is a 5-inch diameter butt welded shell insert plate. This insert plate does not meet API 653 minimum size requirements. This insert plate should be replaced with one that meets API 653 requirements the next this tank is scheduled for major repairs. 47. The bottom edge projection has leafing-type corrosion and coating failure intermittently around the tank periphery. This area should be properly cleaned to determine the extent of the corrosion and then re-coated to minimize further corrosion. 48. The shell-to-bottom joint and bottom edge projection area has coating failure around the entire periphery as well as active leafing-type corrosion of the bottom edge projection. This area should be completely sandblasted and re-coated. 49. Item L is a 5-inch x 0.25-inch lap welded patch plate. The lap patch should be removed and a butt welded insert plate installed according to current API standards (minimum 6-inch patch size required) the next time welded repairs to the shell are performed. 50. The tank nameplate mounting bracket is not attached to the tank. This nameplate should be permanently re-attached to the tank. 51. Due to the extended time this tank has been out of service, a full height hydrostatic test is recommended prior to returning the tank to service.

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NOZZLES

Nozzles A, B, E, G, H and S have a weld spacing between their reinforcing plates and the shell-to-bottom joint less than that required by API 650, Para. 3.7.3. Nozzle F has a weld spacing between the nozzle neck and shell-to-bottom joint less than that required by API 650, Para. 3.7.3. Nozzle D has a weld spacing from the nozzle neck to the adjacent vertical weld less than that required by API 650, Para. 3.7.3. Such practices result in areas of increased stress concentration and possible accelerated corrosion. Visual (VT) inspection of these nozzles did not identify any such corrosion at this time. Additional inspection by Magnetic Particle (MT) methods should be performed (was performed and no identifiable defects were found). 52. Nozzles B and E have a weld spacing between their reinforcing plates and the shell-to-bottom joint less than that required by API 650, Para. 3.7.3. Nozzles T and U have a weld spacing from their nozzle necks to the shell-to-bottom weld less than that required by API 650, Para. 3.7.3. These nozzles should be raised in accordance with API 653, Para. 7.8 at the time the bottom is replaced. Nozzles B to E and E to F have a weld spacing between their reinforcing plates less than that required by API 650, Para. 3.7.3. Item G covers twelve (12) sample spigots that have a weld space between their necks less than that required by API 650, Para. 3.7.3. Such practices result in areas of increased stress concentration and possible accelerated corrosion. Visual (VT) inspection did not identify any such corrosion at this time. Additional inspection by Magnetic Particle (MT) methods should be performed (was performed and no identifiable defects were found). 53. Nozzles A, D, F, H, J and K have a weld spacing between their reinforcing plates and the shell-to-bottom joint less than that required by API 650, Para. 3.7.3. Such practice results in areas of increased stress concentration and possible accelerated corrosion. Visual (VT) inspection of these nozzles did not identify any such corrosion at this time. Additional inspection by Magnetic Particle (MT) methods should be performed (was performed and no identifiable defects were found). 54. Nozzles A, C, D, E, I, O, Q, S and U have a weld spacing between their reinforcing plates and the shell-to-bottom joint less than that required by API 650, Para. 3.7.3. 55. Nozzles N & O and Q & S have a weld spacing between their reinforcing plates less than that required by API 650, Para. 3.7.3. 56. Nozzles C and D have a common reinforcing plate that is welded directly over a vertical weld. API 650 currently allows this practice subject to additional non-destructive examination. This detail has been present for an extended period and visual inspection found no identifiable defects. 57. Nozzles Q & R, R & S and V & W have a weld spacing between the reinforcing plates and nozzle necks less than that required by API 650, Para. 3.7.3.

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NOZZLES

58. Nozzles O to N and F to G have a weld spacing from their reinforcing plate to nozzle neck weld less than that required by API 650, Para. 3.7.3. 59. Item L covers twelve (12) sample spigots that have weld space between their necks less than that required by API 650, Para. 3.7.3. 60. Nozzles G to H, H to J, J to K, K to M and M to N have a weld spacing between their necks less than that required by API 650, Para. 3.7.3. Such practices result in areas of increased stress concentration and possible accelerated corrosion. Visual (VT) inspection did not identify any such corrosion at this time. Additional inspection by Magnetic Particle (MT) methods should be performed (was performed and no identifiable defects were found). 61. Nozzles B, C, H, J and K have a weld spacing between their reinforcing plates and the shell-to-bottom joint less than that required by API 650, Para. 3.7.3. Nozzles D and F have a weld spacing between their reinforcing plates less than that required by API 650, Para. 3.7.3. Nozzle J has a weld spacing from the reinforcing plate to the adjacent vertical weld less than that required by API 650, Para. 3.7.3. These nozzles should be raised in accordance with API 653, Para. 7.8 if the bottom is replaced and the shell is slotted. 62. Nozzles A, J, T and AA have a weld spacing between their reinforcing plates and the shell-to-bottom joint less than that required by API 650, Para. 3.7.3.1. The weld spacing between the reinforcing plate of Nozzle T and the adjacent vertical weld is less than that required by API 650, Para. 3.7.3.1. Such practices result in areas of increased stress concentration and possible accelerated corrosion. Visual (VT) inspection did not identify any such corrosion at this time. Additional inspection by Magnetic Particle (MT) methods should be performed (was performed and no identifiable defects were found). 63. The weld spacing between the neck of Nozzle F to the reinforcing plate of Nozzle G is less than that required by API 650, Para. 3.7.3. Nozzle O has a weld spacing from its neck to the adjacent vertical shell weld less than that required by API 650, Para. 3.7.3. Such practices result in areas of increased stress concentration and possible accelerated corrosion. Visual (VT) inspection did not identify any such corrosion at this time. Additional inspection by Magnetic Particle (MT) methods should be performed (was performed and no identifiable defects were found). 64.

Item Y is a square-cornered door sheet not coincident with the nearest shell horizontal weld seams. API 653, Figure 7-1 suggests that replacement shell plates should have rounded corners with a minimum radius of curvature of Dr /2. The corner areas should be further inspected by Magnetic Particle (MT) methods to determine if any

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NOZZLES

identifiable defects are present (was inspected and no identifiable defects were found) and these areas should be monitored in future for signs of stress concentrations. 65. Nozzle U has a split reinforcing plate with only one telltale hole. API 650, Paras. 3.7.5.1 and 3.7.6.1 indicate reinforcing plates or each segment of the plates if they are not made in one piece should be installed with telltale holes. A telltale hole should be drilled and the space behind the reinforcing plate verified as gas-free prior to any future hot work on this nozzle detail in case any undetected product has leaked into this area. 66. Nozzle J has a reinforcing plate without a telltale hole. API 650, Paras. 3.7.5.1 and 3.7.6.1 indicate reinforcing plates should be installed with telltale holes. A telltale hole should be drilled and the space behind the reinforcing plate verified as gas-free prior to any future hot work on this nozzle in case any undetected product has leaked into this area. The telltale hole should then be left open to the atmosphere. 67. Nozzles J and K have reinforcing plates without telltale holes. API 650, Paras. 3.7.5.1 and 3.7.6.1 indicate reinforcing plates should be installed with telltale holes. Telltale holes should be drilled and the space behind each reinforcing plate verified to be gas-free prior to any future hot work on these nozzles in case any undetected product has leaked into this area. The telltale holes should then be left open to the atmosphere. 68. Nozzles A, B, C, E, F, G, J and K have telltale holes that are plugged. API 650, Paras. 3.7.5.1 and 3.7.6.1 indicate reinforcing plates should be installed with telltale holes left open to the atmosphere. These plugs should be removed prior to returning the tank to service. The telltale holes should then be left open to the atmosphere. 69. Nozzle A has a telltale hole that is plugged. API 650, Paras. 3.7.5.1 and 3.7.6.1 indicate reinforcing plates should be installed with telltale holes left open to the atmosphere. This plug should be removed prior to returning the tank to service. The telltale hole should then be left open to the atmosphere. 70. The internal neck-to-shell weld on Nozzles I and J shows signs of weld corrosion and product stains indicating a leak path. These nozzles should be weld repaired in accordance with API 653. 71. Nozzle J does not have a reinforcing plate as suggested by API 650, Para. 3.7.2.1 which states that, “Openings in tank shells larger than required to accommodate a NPS 2 flanged or threaded nozzle shall be reinforced.” Consideration should be given to installing a reinforcing

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NOZZLES

plate around this nozzle neck at the next opportunity when welding repairs to the shell are to be performed. 72. Nozzle F has its valve welded directly to the shell. This is not an API standard connection detail. This connection should be replaced with an API standard shell nozzle detail the next time this tank is scheduled for major repairs to the shell or when a hydrotest is required due to other repairs. 73. The water draw Nozzle H is a 4-inch threaded nozzle with a 6-inch opening cut in the shell. This is not an API standard detail and is not a recommended practice. This nozzle should be replaced with an API standard nozzle detail (per API 650, Fig. 3-5) the next time this tank is scheduled for major repairs to the shell. 74. The nominal neck thickness of Nozzles A, B, C… has been reduced as a result of service conditions over the life of the item. Consideration should be given to performing further evaluation to determine whether or not the nozzle neck is suitable for continued service without repair or replacement (Note to API Inspector/Technical Report Writer - from a practical standpoint, we should record in the field and include in the report Summary any neck thickness more than 10% less than the nominal thickness. This assumes that the neck was either Sch. 80 or X-strong wall thickness to begin with). 75. The neck thickness of Nozzle G indicates that the nozzle neck is less than the minimum required per API 650, Table 3-6, Column 3. These details have been present for an extended period of time and no immediate corrective action is required. Consideration should be given to further evaluation to determine whether or not the nozzle neck is suitable for continued service without repair or replacement, or to modifying these details as necessary at a future opportunity when welded repairs to the tank are planned. The neck thickness of Nozzles G, L, P, and R indicates that the nozzle necks are less than the minimum required per API 650, Table 3-6, Column 3. These details have been present for an extended period of time and no immediate corrective action is required. Consideration should be given to further evaluation to determine whether or not the nozzle necks are suitable for continued service without repair or replacement, or to modifying these details as necessary at a future opportunity when welded repairs to the tank are planned. 1.

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NOZZLES

The neck thickness of Nozzle J-1 does not meet the minimum requirements of API 650, Table 3-6, Column 3. Consideration should be given to replacing this nozzle with details that meet minimum API 650 nozzle requirements (ref. Fig. 3-5).

1. The neck thickness of Nozzles A, B, C…. indicates that the nozzle neck is less than Sch. 80 or X-strong thickness required by API standards of construction. These details have been present for an extended period of time and no immediate corrective action is required. Consideration should be given to further evaluation to determine whether or not the nozzle neck is suitable for continued service without repair or replacement, or to modifying these details as necessary at a future opportunity when welded repairs to the tank are planned (Note to API Inspector/Technical Report Writer - this situation should be noted in the inspection checklist and this comment used in the report Summary whenever it is evident from UT readings that the nozzle neck does not meet minimum API 650 neck thickness requirements from original construction or later modification). 2. Nozzles A, B, E, F, and H have reinforcing plates that do not meet the minimum size requirements of API 650 (Ref. Table 3-6, Columns 5 and 6). These nozzles should be replaced with API standard nozzle details the next time this tank is scheduled for major repairs to the shell.(IRD) 3. Nozzles A, B, E, F, and H have reinforcing plates that do not meet the minimum thickness requirements of API 650 (Ref. Table 3-7, Column 1). These nozzles should be replaced with API standard nozzle details the next time this tank is scheduled for major repairs to the shell. (IRT) 4. Nozzle G is a manway with a six-inch product suction line penetrating its cover. This detail (withdrawal line through manway cover plate) is not a common practice. Consideration should be given to replacing this detail with a standard API shell nozzle penetration the next time this tank is scheduled for major repairs. 5. There is a riveted door sheet located at Station 123.0 feet (measured circumferentially CCW from Manway A). This riveted door sheet is an API Appendix A shell connection which is not normally used in tanks built to more current industry standards. Consideration should be given to replacing this shell connection with an API flush-type cleanout connection. 6. Nozzle F is a blind flange that has thread engagement less than flush on several bolts. This bolting detail should be replaced with studs of sufficient length to provide at least one thread per stud extending past the nut.

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NOZZLES

7. Nozzles D and J are 10-inch product lines with 16-inch openings cut in the shell. This results in the nozzle neck being welded to the reinforcing plate but not to the shell. The size of the reinforcing plate is also less than required for this size shell opening. These are not API standard details and are not recommended practices. These nozzles should be replaced with API standard nozzle details (per API 650, Fig. 3-5) the next time this tank is scheduled for major repairs to the shell. 8. The water draw Nozzles E, I and S are threaded nozzles. Consideration should be given to replacing these nozzles with API 650 flanged nozzle details per Figure 3-5. 9. Nozzles B, D, E and F are 3-inch threaded water draw nozzles. Consideration should be given to replacing these nozzles with new API flanged nozzle details at a future opportunity when the tank is taken out of service for welded shell repairs. 10. Nozzle I is a 3-inch nozzle installed offset into a 5-inch shell opening with very poor quality welding between the nozzle, shell and reinforcing plate. This nozzle should be replaced with an API standard nozzle detail (per API 650, Fig. 3-5) at a future opportunity when welded repairs to the shell are performed. 11. Nozzles D and Q have their valve bodies welded directly to the shell. This is not an API standard detail. These connections should be replaced with API standard shell nozzle details the next time this tank is scheduled for welding repairs to the tank shell or when a hydrotest is scheduled for other repairs. 12. Nozzle J appears to have been installed by hot tapping. This nozzle should have the sharp edges removed and the inside neck-to-shell detail should be seal welded. 13. The tank gauge and high level alarm systems should be tested, repaired if necessary and calibrated prior to returning the tank to service. 14. The tank ground system has two (2) locations with no ground cable or rod. A ground cable and rod should be properly installed at these locations prior to returning the tank to service if it is determined that additional tank grounding is required. 15. Nozzle N (the roof drain) is bolted to its reinforcing plate. This is not an API standard detail and should be replaced with a welded API flanged nozzle detail.

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NOZZLES

16. The tank currently does not have a high level alarm. Consideration should be given to installing a high level alarm system or alternative overfill protection device prior to returning the tank to service. 17. The reinforcing pad for Nozzle K is welded over a vertical seam. This practice also presents risks of accelerated corrosion and stress concentration. API 650 currently allows this practice subject to additional non-destructive examination. This detail has been present for an extended period of time and Visual (VT) inspection found no identifiable defects. The nozzle detail should be monitored in future. 18.

Nozzles A, B, C, D, N, Q, R, T and X have square-cornered reinforcing plates. API 650, Figure 3-5 suggests that reinforcing plates should have rounded corners with a minimum radius of curvature of D r /2. These details have been present for an extended period of time and no immediate corrective action is required. Consideration should be given to replacing these reinforcing plates with API standard detail plates at a future opportunity when other welding repairs to the shell are planned.

19. The tank ground system has three (3) locations with improper connections. Item J located at Station 96.8 feet is not attached at the rod. Item M located at Station 154.4 feet, the rod is pulled out of the ground and laying on the surface. Item Y located at Station 333.7 feet is not attached at the shell. All locations are measured circumferentially CCW from Manway A. Consideration should be given to further evaluating the need for grounding of this tank (reference API 2003 for additional guidance). 20. There is an attachment weld failure on the stairway between Treads 28 and 29. These attachment welds should be repaired before the tank is returned to service or use of the stairway restricted due to personnel safety concerns. 21. Nozzles C and F were installed by hot tapping. These nozzles should be have the sharp edges removed and each inside neck-to-shell detail should be seal welded. 22. Nozzles J and K are 10-inch nozzles with a 14.5-inch hole cut in the shell resulting in the nozzle being welded to the reinforcing plate. This is not a standard API nozzle detail and is not a recommended practice. Consideration should be given to replacing this nozzle detail with a standard API nozzle connection detail at a future opportunity where welded repairs to the shell are to be performed. 23. Nozzle D is a blind flange that has thread engagement less than flush on several bolts. This nozzle has a plugged telltale hole and seepage

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NOZZLES

from a hole within the seal weld on the internal side. Consideration should be given to replacing the bolting with studs of sufficient length to provide at least one thread extending past the nut on each stud and to repairing the internal seal weld and pressure testing the reinforcing plate. 24. Nozzle Q was installed by hot tapping and the trough on the inside of the tank is only partially welded to the shell. This nozzle is not in service. It is blinded on the outside of the tank and does not currently have external connecting piping. The reinforcing plate on this nozzle does not have rounded corners or a telltale hole. Consideration should be given to carefully removing the trough from the shell grinding the sharp edges and possibly seal welding this nozzle on the inside, but only after a telltale hole is drilled in the reinforcing plate outside and the space is verified to be gas-free before any hot work is performed. 25. Nozzle H does not have an adequate reinforcement plate in accordance with API 650. This nozzle should have its reinforcement plate replaced using an API standard detail at a future opportunity when welding repairs to the tank shell are to be performed. 26. Nozzles D and K have evidence of leakage around the valve stems. The valve packing should be replaced on these nozzles valves prior to returning the tank to service. 27. The water draw line piping support welds at the support to the pipe, near the shell, are cracked. These welds should be repaired or the support detail should be changed to one providing more flexibility of future movement. 28. Nozzles M, O and the RVP nozzle were installed by hot tapping. These nozzles should have the sharp edges removed and seal welded on the inside. These three (3) nozzles also have plugged telltale holes. After completion of the repairs, the plugs should be removed and the telltale holes left open. 29. Nozzle F appears to have been installed by the hot tap method. The sharp edges remaining on the inside of the shell should be removed and the nozzle seal welded on the inside. 30. Nozzles E and G have sharp edges and burrs on the inside of the shell. These conditions should be corrected prior to returning the tank to service. 31. Nozzles C and H both have their valves welded directly to the shell. This is not an API standard detail and not a recommended practice. Both

Nelson Words

NOZZLES

nozzles should be replaced with an API standard shell nozzle detail at a future opportunity when welded repairs to the shell are performed. 32. The attachment weld at Station 173.0 feet (measured circumferentially CCW from Manway A) has a visual indication of possible weld defect. The coating should be removed and a surface examination such as Magnetic Particle (MT) or Liquid Penetrant (PT) performed to verify its integrity. 33. There is an open area between the intermediate platform handrail and the stairway handrail that is a safety concern. A safety chain or other suitable device should be installed to eliminate this open area. 34. The shell penetration for the water draw (Nozzle G) is cut through an existing insert plate. A Magnetic Particle (MT) examination was performed on the penetration area and no indications were identified. This nozzle should be monitored during future inspections. 35. The cathodic protection cable attachment to the shell located at Station 187.2 feet (measured circumferentially CCW from Manway A) is detached. Consideration should be given to re-attaching this connection to the shell. 36. The tank gauge pole is supported by the bottom of the tank and is only slotted up to a level even with the top of the second shell course. This comment is supplied as information only. 37. Nozzle H is a six-inch threaded coupling that does not have a reinforcing plate. This is not an API standard nozzle detail. Nozzle reinforcement calculations indicate this nozzle does not provide adequate reinforcement. Consideration should be given to replacing this nozzle with an approved API standard detail nozzle design at a future opportunity when welded repairs to the shell are to be performed.

Nelson Words

FIXED ROOF

Nozzles B, C and D are bolted to the roof to accommodate the Enraf gauge and the high level alarm. Consideration should be given to replacing these bolted nozzles with API 650 welded roof nozzle details (Ref. Fig. 3-16) or appropriate measures should be taken to insure that these details do not allow water to leak into the tank or product vapor to escape out. 38. The fixed roof has three (3) six-inch pressure/vacuum vents that are painted shut. Consideration should be given to verifying the requirement for these vents and for the cleaning, testing and calibrating of them if they are required for tank operation. 39. The roof coating is failing near the frangible joint with areas of peeling, rust-colored stains and corrosion. These areas should be sandblasted and re-coated. 40. Nozzles A and B are bolted to the roof. Consideration should be given to replacing these bolted details with welded API 650 roof nozzle details (Ref. Figure 3-16) or appropriate measures taken to insure that these details do not let water leak into the tank or product vapor to escape out. 41. Nozzles B, C and D are bolted to the roof to accommodate the level gauge, temperature instrumentation and the high level alarm. Consideration should be given to replacing these bolted nozzles with API detail welded roof nozzles or appropriate measures should be in place to insure that these details do not allow water to leak into the tank or product vapor to escape out. 42. Nozzle E is bolted to the roof to accommodate the system. This bolted nozzle should be replaced with roof nozzle detail (Ref. Figure 3-16) or appropriate be in place to insure that this detail does not allow the tank or product vapor to escape out.

high level alarm a welded API 650 measures should water to leak into

43. There is a safety rail extending to the center of the roof from the stairway platform that is both bolted to the roof and to its attachment members. Consideration should be given to replacing all bolted connections with welded ones. 44. The flame arrestor should be cleaned, tested and calibrated to insure proper operation. 45. There is one overflow located over the stairway. Consideration should be given to either relocating this overflow or sealing it closed.

Nelson Words

FIXED ROOF

46. The mid-rail for the roof safety railing at the top of the stairway has a failed weld. The attachment weld at the mid-rail should be repaired as soon as possible to eliminate a possible personnel safety hazard. 47. There is a safety rail extending from the stairway platform railing to the gauge support structure that is both bolted to the roof and to its attachment members. Consideration should be given to replacing all bolted connections with welded ones. 48. There are two (2) ten-inch pressure/vacuum vents with flame arrestors. Consideration should be given to verifying they provide adequate relief for the tank and to cleaning, testing and calibrating both units. 49. There is an old gauge access hatch that is bolted to the roof. This hatch is missing three (3) bolts and allows water to enter the tank. Consideration should be given to replacing this hatch with a seal welded patch plate or appropriate measures should be taken to insure that this detail does not allow water into the tank or product vapor to escape out. 50. The roof has four (4) eight-inch vacuum breakers that are bolted connections. Consideration should be given to determining the requirement of these vents and either replacing them with welded nozzles or removing them and seal welding patch plates on the roof. If required for operation, appropriate measures should be taken to insure that these details do not allow water into the tank or product vapor to escape out. These vents should be cleaned and calibrated if they are to remain in service. 51. The tank does not have a ladder from the fixed roof to the floating roof. The gauge pole is an eight-inch aluminum pipe that is welded to the tank bottom. Consideration should be given to replacing the gauge pole with a combination gauge pole/ladder assembly to provide access to the floating roof. 52. The hatch cover on the gauge pole is missing a hinge and is not attached to the hatch. This condition should be corrected. 53. The roof center vent does not have a screen to prevent birds from entering the tank. This vent should have a screen installed over the opening.

Nelson Words

FLOATING ROOF

The floating roof seal is a foam log. This seal is soaked with product and should be replaced prior to returning the tank to service. 54. Nozzle C, vacuum breaker, currently does not have a striker plate under its leg. Consideration should be given to installing a seal welded striker plate under the vacuum breaker leg. 55. The roof drain sump is full of debris. The sump and drain line should be cleaned out to allow for proper drainage of the roof. The roof currently is retaining a large amount of water around the center pontoon chamber. This condition should be monitored after the roof is returned to service to verify that the water properly drains away. 56. The grounding cable from the shell to the rolling ladder is not connected. This cable connection should be repaired or replaced prior to returning the tank to service. 57. The vacuum breakers have only one leg setting (low roof position) and are blind-flanged, rendering them inoperable. The need for and operability of the vacuum breakers should be evaluated and any necessary modifications or repairs should be performed. 58. The primary seal is a mechanical shoe. The vapor barrier and the shoes are severely deteriorated. A new primary seal should be installed prior to returning the tank to service. 59. The floating roof seal has been removed. A new primary seal should be installed prior to returning the tank to service. 60. The foam log primary seal was removed prior to the inspection. A new primary seal is scheduled to be installed prior to returning the tank to service. 61. The floating roof nozzle vapor gaskets and appurtenance vapor seals should be replaced prior to returning the tank to service. 62. The mechanical vacuum breaker leg is not adjustable and will only operate when the roof is in low position. Consideration should be given to making the vacuum breaker leg adjustable (pin settings for both high and low roof positions). 63. The floating roof was not accessible due to the unsafe condition of the vertical ladder. Visual inspection of the seal from the underside of the floating roof revealed no apparent defects. The vertical ladder should be repaired if access via that means is ever anticipated or desired.

Nelson Words

FLOATING ROOF

64. The floating roof is a steel pan with legs in fixed low roof position which was installed in 1972. This roof does not have a vacuum breaker. 65. The floating roof appurtenance vapor seals (i. e. vapor seal at the gauge pole well or around column wells in internal floating roofs) should be replaced prior to returning the tank to service. 66. The primary seal is a foam log. This seal has gaps of 0.5 inch to 1.25 inches for over 45% of the tank perimeter. This seal should be repaired or completely replaced prior to returning the tank to service. 67. The primary seal mechanical shoes are severely corroded intermittently around the tank. The primary seal shoes should be replaced prior to returning the tank to service. 68. The mechanical vacuum breaker leg is not adjustable and will only operate when the roof is in low position. Consideration should be given to making the vacuum breaker leg adjustable. 69. The floating roof rim vent is not operable. This vent should be repaired to allow for proper operation. 70. The rolling ladder platform is bolted to the roof. Consideration should be given to replacing the bolted connections with welded details. 71. The floating roof appurtenance seals (i. e. vapor seal around gauge pole well or at column wells in internal floating roofs) show signs of deterioration and should be replaced prior to returning the tank to service. 72. There are three (3) floating roof legs located on Plates 22, 31 and 37 that are too short and do not provide support to the roof. There is also one (1) leg missing on Plate 27. These conditions should be corrected prior to any additional work being performed on or under the roof. 73. The mechanical vacuum breaker legs are not adjustable and will only operate when the roof is in low position. Consideration should be given to making the vacuum breaker legs adjustable so that they will operate the vents with the roof in either low or high position. 74. Nozzles B and L are combination pressure/vacuum vents. Nozzle L also has a flame arrestor. This tank has four roof vents and four shell vents that were installed after original construction. Due to the additional venting to the tank, Nozzles B and L may no longer be required for tank operation. Consideration should be given to determining the need for these vents and either removing them or cleaning, testing and calibrating them prior to returning the tank to service.

Nelson Words

FLOATING ROOF

75. There are two (2) six-inch pressure/vacuum vents. These vents should be cleaned, tested and calibrated prior to returning the tank to service. 76. The roof bolting securing the sheeting to the channels is severely corroded. There is one area near the shell where the bolting is loose and not securing the sheeting properly. Consideration should be given to replacing this bolting with a non-corroding material. 77. The roof seal is an old style mechanical system that is worn and may not have much service life remaining. The seal fabric was removed prior to the inspection. Consideration should be given to replacing the old mechanical seal system with a new design. 78. The rolling ladder is missing a handrail at the top on one side. The support structure does not have a deck to step on to at the bottom of the ladder. The ladder does not have self-leveling stairs. The rolling ladder should be repaired to insure a safer and more operable condition. 79. There are five (5) roof legs that do not rest on the tank bottom. The legs are located on Plates 24, 48, 50, 69 and 70. These roof legs should be modified/adjusted so that they provide adequate support for the floating roof. 80. The roof coating system has failed and there is rust and corrosion on the roof deck. Consideration should be given to sandblasting and recoating the roof deck. 81. The top of the pontoon roof deck has been sand blasted around the outside perimeter following the removal of the seal material. This area has scattered pitting with an average depth of 0.060 inch. This seal should be replaced with a new system that will not retain product at the rim and the roof re-coated to minimize further corrosion. 82. There are two (2) pontoons that have product inside the chambers on the outside perimeter. These pontoons should be removed and replaced. 83. The roof drain sump is full of dirt and debris. Consideration should be given to cleaning the sump and the drain line. 84. The floating roof is an aluminum pontoon. The roof has three (3) missing legs, one (1) leg that is bent, thirty-nine (39) legs out of plumb and ten (10) legs that are corroded and missing their feet. The roof is in severe service due to the high velocity of product entering the tank, especially near the diffuser line where pontoons were added to provide additional

Nelson Words

FLOATING ROOF

flotation. Consideration should be given to replacing this roof with one that could better withstand the service presented by these conditions. 85. The inspection found two (2) grounding cables between the floating roof and the shell that are no longer attached. These cables are to help prevent the build-up of static electricity. Consideration should be given to re-attaching these ground cables (shunts) from the floating roof to the shell. 86. The floating roof has three (3) vacuum breakers that are currently not operable. Two (2) vacuum breakers are missing one of the guide vanes. All three (3) vacuum breakers are not pinned and would not operate at the current roof position. Consideration should be given to correcting these conditions before the tank is returned to service. 87. The rolling ladder is missing a handrail at the top on one side. There is mechanical damage to the ladder and handrail midway down the ladder and on the support structure at the base of the ladder. The ladder runway does not have grating to step on to at the bottom of the ladder. The ladder does not have self-leveling stairs. The rolling ladder was sand blasted prior to the inspection. The rolling ladder damage should be repaired to a safer and more operable condition before the tank is returned to service. 88. The mechanical vacuum breaker leg is not adjustable and will only operate when the roof is in low position. Consideration should be given to making the vacuum breaker leg adjustable. 89. There are three (3) roof legs that do not rest on the tank bottom. The legs are located on Plate numbers 36, 56 and 91. Consideration should be given to adjusting or modifying the length of these roof legs so that they provide adequate support for the floating roof. 90. There is one (1) vacuum breaker six (6) inches in diameter on the roof. The leg of this vacuum breaker is bent preventing its proper operation This vacuum breaker should be repaired prior to returning the tank to service. 91. The floating roof rim vent is full of debris. This vent should be cleaned so that its proper operation can be performed. 92. The roof drain is an old style pipe system. This drain system should be cleaned and pressure tested to verify its integrity or completely replaced with a new style system. 93. The roof drain line has failed on both the inside and outside of the tank. There is currently a bolted clamp-on seal on the outside of the tank

Nelson Words

FLOATING ROOF

near the valve to prevent product leakage. This line is no longer used to drain water from the roof due to the installation of a geodesic dome. This line should be completely removed or isolated as soon as access to the tank can be achieved. A close visual inspection and possible Ultrasonic (UT) examination of the remaining piping should be performed to verify its integrity or a pressure test should be performed once the tank is emptied and before the tank is returned to service. 94. The roof is currently pinned in high position and there are only cotter pins on one side of the roof leg pins. Consideration should be given to installing cotter pins on both sides of the leg pins to keep them in position. 95. The rolling ladder has two treads that have come off their pivot hinges and one tread missing at the base of the ladder. These conditions should be corrected before the tank is returned to service to allow continued safe operation of the ladder. 96. The floating roof primary seal has deteriorated with large areas of the seal missing and the secondary seal is starting to show signs of deterioration. A new primary and secondary seal should be installed prior to returning the tank to service. 97. The floating roof vacuum breaker legs are currently set for the low roof position. The roof is currently set in high position, making the vacuum breakers inoperable. The roof legs should be set to operate in low roof position after returning the tank to service. 98. The pontoon support straps on the pontoons above Plates 41 and 89 have failed and the strap on the pontoon above Plate 5 is torn. These straps should be replaced prior to returning the tank to service. 99. There are eighty-five (85) floating roof legs with no striker plates. Consideration should be given to installing seal welded striker plates, steel striker plates permanently affixed to the bottom by alternate means (epoxy) or manufacturer’s aluminum leg pads (with pins) under each roof leg. 100.There are two (2) twenty-inch combination pressure/vacuum vents on the floating roof. Consideration should be given to cleaning, testing and calibrating these vents. 101.The floating roof has six (6) legs that are not plumb on Plates 3, 8, 19, 21, 40 and 49. Consideration should be given to re-positioning these roof legs.

Nelson Words

FLOATING ROOF

102.The two (2) gauge openings and the ladder opening on the floating roof do not have vapor seals to prevent the escape of product vapors. These penetrations should have vapor seals installed around their openings to reduce the escape of product vapors. 103.There is a ten-inch vacuum breaker vent on the floating roof. This vent is currently not operable due to the adjustment pin being removed. This pin should be replaced at the proper setting prior to returning the tank to service. 104.The floating roof has twenty-four (24) legs that are missing one (1) of their cotter pins and two (2) legs that are missing both cotter pins that help keep the leg pins in proper position. These cotter pins should be replaced prior to returning the tank to service. 105.Safety Note: The access to the rolling ladder has been modified due to the installation of the geodesic dome. The current access is not safe due to the lack of steps from the platform to the rolling ladder. This detail should be modified or changed to increase the personnel safety at this access point. 106.The floating roof primary seal is a mechanical shoe. The vapor seal material and shoes are starting to deteriorate with areas of severe corrosion and holes. This seal should be replaced. The secondary seal is a wiper. This seal is in acceptable condition. 107.The roof drain is an old style mechanical joint drain. There are several areas of damage along the fixed piping. The useful remaining life of this drain is limited and consideration should be given to replacing it with a more modern system designed for better flow and reliability or this drain should be pressure tested prior to returning the tank to service. 108.The rolling ladder is missing a handrail at the top on one side. The ladder does not have self- leveling stairs. The rolling ladder should be repaired to a safe operating condition before the tank is returned to service.

Nelson Words GEODESIC DOME The dome attachment plate bolting to the roof near the rolling ladder is loose and the plate is not normal to the attachment point. Consideration should be given to correcting this condition. 109.There are four (4) areas of the bird screening that have fallen away from the dome. Consideration should be given to replacing the screens. 110.There is visual evidence on the internal floating roof deck (water stains) that the dome has leaks. The roof leaks should be repaired or the floating roof drain system should be kept in operation.