Eielson AFB-6239 OOS Final Report.pdf
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About this file
This document is an API 653 Tank Inspection Report for Tank 15 at the E-2 Fuels Complex at Eielson Air Force Base, Alaska.
The report summarizes the findings of a comprehensive out-of-service internal and external inspection performed on August 15, 2011. The inspection assessed the tank's hydraulic and structural integrity, evaluated its suitability for continued service, and provided recommendations for mandatory repairs, non-mandatory recommended repairs, and long-term serviceability. The tank was found to be in acceptable condition and suitable to return to service, with no mandatory repairs required. Recommended repairs included addressing sealant failures, bird nests, coating issues, and seals on the floating pan. The report recommends the next API external inspection be scheduled by August 2016 and the next API internal inspection by August 2031, or sooner if changes in condition occur. Overall, the tank was determined to be in a condition suitable for continued service.
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AFCESA CONTRACT FA8903-08-D-8770, SK 19
TANK 15 (FACILITY NO. 6239)
API 653 TANK INSPECTION AND
SUITABILITY FOR SERVICE EVALUATION
(FINAL: PRE-REPAIR)
Eielson Air Force Base
October 2011
Prepared For:
Air Force Civil Engineer Support Agency (AFCESA) 139 Barnes Drive, Suite 1 Tyndall AFB, FL 32403-5319
Presented By:
AECOM
8005 Outer Circle Road Brooks City-Base, Texas 78235
Prepared By:
David A. Stchyrba, P.E., API 653 Certificate No. 27187
Submitted By:
Stephen S. Brooks, P.E.
Principal, API 653 Certificate No. 17 2525 Gambell Street, Suite 200, Anchorage, AK 99503
EEI PROJECT 10-5632
ABSTRACT
Enterprise Engineering, Inc. (EEI) has completed a comprehensive, out-of-service internal and external inspection and suitability for service evaluation of Tank 15 at Eielson AFB, Alaska.
The inspection was performed on August 15, 2011 in accordance with the applicable criteria of API Standard 653, UFC 3-460-01, and the Statement of Work.
This report provides inspection findings, tank suitability for service evaluation, conclusions, and recommendations for repair, prior to returning the tank to service. Recommendations for continued long-term service are also provided.
EEI recommends the next API external in-service inspection be scheduled no later than August 2016 (5 years from 2011 inspection), or sooner if a change in condition has occurred.
EEI recommends the next API internal out-of-service inspection be scheduled no later than May August 2031 (20 years from 2011 inspection), or sooner if a change in condition has occurred.
In accordance with API Standard 653, this report satisfies the requirement for an out-of-service, integrity inspection and as such, should remain available as a historical record for future reference.
I hereby acknowledge that being familiar with the provisions of API Standard 653, the inspection and evaluation was performed in accordance with the provisions of API Standard 653 and good engineering practices, and with the exercise of usual and customary care.
October 21, 2011 David A. Stchyrba, P.E.
API 653 AST Inspector Certificate No. 27187
This tank inspection has determined that mandatory repairs are not required prior to return to service. Tank 15 may be returned to service. Recommended repairs have been identified, an if possible, should be completed before returning the tank to service.
Tank 15 – API 653 Inspection TABLE OF CONTENTS Eielson Air Force Base, Alaska October 2011 EEI Project No. 10-5632
TABLE OF CONTENTS
Page
SUMMARY
Scope General
INSPECTION ASSESSMENT
Hydraulic Integrity Structural Integrity Next Inspection
REPAIR ITEMS
Standard of Care Required Repairs Prior to Return to Service (Mandatory) Recommended Repairs Prior to Return to Service (Non-Mandatory) Assessment of Compliance with Current Military Criteria Recommended Repairs for Long Term Serviceability
COATING SYSTEM
Interior and Exterior Coating Requirements Out of Service Concerns
SUITABILITY FOR SERVICE EVALUATION
Corrosion Rates Tank Floor Corrosion Rates Hydraulic and Structural Integrity
ADDITIONAL DISCUSSION ITEM
Gauge Tubes
CLOSURE
Conclusions Project Team
APPENDICES
Tank Inspection Data Sheet and Evaluation Items ................................................... Tab A Non-Destructive Examination (NDE) and Evaluation Criteria ................................... Tab B Tank Drawings .........................................................................................................Tab C Tank Photographs ....................................................................................................Tab D NDE Results ............................................................................................................. Tab E Calculations .............................................................................................................. Tab F Coating Requirements ............................................................................................ Tab G Repair Locations .................................................................................................... Tab H Preliminary Inspection Report ................................................................................... Tab I Rough Order Magnitude (ROM) Costs ..................................................................... Tab J
Tank 15 – API 653 Inspection Page 1
EEI Project No.: 10-5632
TANK 15
API 653 TANK INSPECTION
SUITABILITY FOR SERVICE EVALUATION
Eielson AFB, Alaska
SUMMARY
Scope
Enterprise Engineering Inc. (EEI) has been retained to perform an out-of-service internal and external inspection of Tank 15 at the E-2 Fuels Complex at Eielson AFB, Alaska. The inspection was performed on August 15, 2011. The inspection was performed in accordance with the applicable portions of API Standard 653, UFC 3-460-01 and the Statement of Work.
The API 653 criteria were followed in terms of procedure and evaluation to the greatest extent possible. Inspection findings and recommended repairs are provided below.
The scope of this project is to determine the structural and hydraulic condition of the tank, determine suitability for service, provide written recommendations for repairs and develop recommendations for long-term service based on visual inspection and non-destructive examination (NDE).
General
Tank 15 is a field erected above ground storage tank. The tank was originally fabricated and erected in 1952. It was relocated in 1998 and provided with a new floor, secondary containment liner and set on a new concrete ringwall. The tank is 60 feet in diameter and 31 feet 8-½ inches high and of welded construction with butt-welded shell plates and lap-welded floor and roof plates. The tank is equipped with an aluminum honeycomb floating pan and the nominal shell capacity is 15,000 bbls. Tank 15 is currently in JP-8 service.
INSPECTION ASSESSMENT
The Appendices in this report include a comprehensive table identifying tank features with findings and conclusions as appropriate. The Appendices also contain numerous tables with full reporting of data taken. The following discussion only addresses key integrity issues.
Tank 15 is considered suitable to return to service as no mandatory repairs were identified. The following are significant findings of the inspection.
Hydraulic Integrity
Hydraulic integrity is the ability of the tank to hold product without compromise to the boundaries of the floor and shell.
Visual inspection of the tank shell found no indications of leakage. A pit survey was conducted for topside corrosion on the floor and no pits were identified requiring repair. A magnetic flux leakage (MFL) scan of the tank floor found no relevant indications of corrosion on the bottom side of the floor requiring repair. Tank 15 is in acceptable hydraulic condition.
Tank 15 – API 653 Inspection Page 2
EEI Project No.: 10-5632
Structural Integrity
Structural integrity is the capability of the tank to remain freestanding, with or without product, under the conditions of its design basis. Structural attributes include the floor, shell, roof and their attachments. Ultrasonic inspections of the shell were performed on the first course and on each course up the exterior spiral stair. From interpretation of ultrasonic test (UT) readings recorded, only minor metal loss due to corrosion were observed. Based on this inspection of the accessible components, Tank 15 is in acceptable structural condition.
Next Inspection
API 653 recommends the interval to the next internal inspection be determined based on known corrosion rates, but in no case shall the interval exceed 20 years from the date of inspection.
When corrosion rates are not known or well established, API 653 recommends that the tank be inspected within 10 years. A maximum interval between inspections of 10 years is also commonly used in many government and commercial facilities.
Based on the current corrosion rates, the useful life of the tank exceeds the 20 year API interval restriction using the calculated corrosion rate. As the remaining metal thickness of the floor and shell, after an additional 20 years of service, is above minimums, corrosion conditions will not govern the next required inspection interval. EEI recommends that the next API internal inspection should be scheduled no later than 20 years from the inspection date, or sooner if a change in tank condition has occurred. In the interim, a limited out-of-service inspection of the coating should be performed during maintenance cleanings. EEI acknowledges that a 20 year inspection interval exceeds the 10 year interval commonly used by the government but the low corrosion rates support the longer interval.
An external in-service inspection be conducted in accordance with API 653 requirements no later than August 2016 (5 years from 2016 inspection), or sooner if a change in condition has occurred.
REPAIR ITEMS
Based upon the API field inspection, engineering judgment and knowledge of funding practices, recommendations developed are listed below as required (mandatory), recommended (non-mandatory), recommended per military criteria and recommended for long term serviceability.
Standard of Care
All repairs shall strictly meet the requirements of API 650 and API 653 regarding material, welding procedures and qualification of welders, non-destructive examination (NDE) of welding and testing requirements. Obtaining hot work permits and developing the appropriate hot work procedure for the tank floor is the responsibility of the repair contractor, and shall consider the tank has been in petroleum service. The provisions of API 2207 “Preparing Tank Bottoms for Hot Work” shall be considered.
Tank 15 – API 653 Inspection Page 3
EEI Project No.: 10-5632
Required Repairs Prior to Return to Service (Mandatory)
Mandatory repairs are repairs that are critical to the hydraulic and structural integrity of the tank and are required prior to returning Tank 15 to service.
• The inspection of Tank 15 found no significant deficiencies that would require mandatory repair and prevent returning the tank to service.
Recommended Repairs Prior to Return to Service (Non-Mandatory)
The repairs listed below are not mandatory per API 653 or for structural and hydraulic integrity of the tank. EEI highly recommends these repairs for long-term preservation and integrity of the tank, and believes that the repairs should be performed while the tank is out-of-service.
1. The sealant between the floor projection (chine) and the concrete ringwall is failing at several locations. The following repair is recommended:
• Remove the sealant from the perimeter of the tank.
• Clean the surfaces to be sealed.
• Provide jet fuel-resistant polysulfide sealant between the floor projection and the ringwall.
2. Tank 15 is equipped with two standpipes as part of the leak detection system. Water was observed in the bottom of each pipe. A sheen was also visible and a hydrocarbon odor was detected. The following repair is recommended:
• Drain the fluid from the standpipes.
• Test the fluid for the presence of hydrocarbons.
• Monitor the standpipes for future accumulation of fluid.
• Note: No defects were observed in the floor as part of the inspection to suggest that there is a leak. Facility personnel reported that Tank 15 may have been one of the last tanks at Eielson AFB that was provided with an oil sand bottom. The project drawings and specifications were made available for review. The specifications called for an oil sand bottom. Documentation was not available to verify the as-built condition.
3. Minor bulges/depressions were observed in the first shell course. The defects have been attributed to the relocation of the tank to its current site. The operators report that the floating pan cannot be set at its low leg position because it will hang up on the defects. The following is noted:
• No repair is recommended at this time. Monitor the defects as part of routine maintenance.
4. Tank 15 is equipped with 6 overflow ports. A screen is present at the opening in the shell but not at the opening in the underside of the port. A significant number of bird nests were observed within the ports. From within the floating pan, it appears that the screens in the shell are becoming plugged. Plugged screens will affect the tanks ability to breathe during filling and emptying operations. The following repair is recommended:
• Remove all of the bird nests.
• Provide bird and insect screens at the underside of each overflow port.
Tank 15 – API 653 Inspection Page 4
EEI Project No.: 10-5632
• Note: The removal of the bird nests must be co-ordinated with base environmental as there are restrictions on the time frame when the work may be performed.
5. Tank 15 is equipped with an 8 inch gooseneck atmospheric vent. The opening is not equipped with a screen. The following repair is recommended:
• Provide a bird and insect screen at the opening of the vent.
6. The telltale hole in the reinforcing plate at manway #1, manway #2, the 8 inch fill, 8 inch issue, 4 inch low fuel and the 3 inch water draw-off nozzles are open. The following repair is recommended:
• Pack the tell tale holes with general purpose grease to prevent moisture migration between the reinforcing plate and the shell.
7. Minor coating failure was observed on the shell appurtenances and roof appurtenances. The following repair is recommended:
• Remove the coating from the affected areas, clean and recoat to prevent further degradation.
8. Approximately 10 square feet of coating failure was observed on the tank roof. The following repair is recommended:
• Remove the coating from the affected areas, clean and recoat to prevent further degradation.
9. Approximately 16 square feet of coating failure was observed on the interior tank floor. The following repair is recommended:
• Remove the coating from the affected areas, clean and recoat to prevent further degradation.
10. Corrosion was observed on the product recovery tank. The following repair is recommended:
• Remove the coating from the affected areas, clean and recoat to prevent further degradation.
11. The 8 inch manual gauge hatch is located within the cover plate of the roof manway. Only two bolts are present in the flange. The following repair is recommended:
• Provide the remaining missing bolts.
12. Tank 15 is equipped with an aluminum honeycomb floating pan. The floating pan is equipped with a primary (bottom) and secondary (top) wiper seal. Both wipers have folded under at several locations. The following repair is recommended:
• Manually readjust the wiper seals so that they oriented correctly.
13. Seals have been provided at the penetrations in the floating pan for the gauge tube, combination ladder/gauge tube and the center column. The seals have deteriorated. The following repair is recommended:
• Replace the seals at the pan penetrations.
Tank 15 – API 653 Inspection Page 5
EEI Project No.: 10-5632
14. Tank 15 is equipped with a Varec tape gauge. Water was observed inside the tape gauge display. The following repair is recommended:
• Provide a new tape gauge system calibrated in 1/16 inch gradations complete with gauge head, conduit, wires, float and springs.
• This recommendation is based on historical observations by EEI at multiple government facilities when reviewing repair vs. replacement costs.
15. Tank 15 is equipped with ice/snow shields at multiple locations to protect minor piping.
Unprotected hydraulic tubing is present at the valve on the water draw-off nozzle. The following repair is recommended:
• Provide an ice/snow shield above the hydraulic tubing. From past experience, it is the suggestion of EEI to provide a 6 inch x 6 inch x ¼ inch angle x 2 feet long with the heel facing up. Weld the angle to a ¼ inch thick doubler plate that is 10 inches wide and 14 inches long with 2 inch radius corners. The angle should be braced with a ¼ inch thick tapered gusset plate, oriented vertically.
16. Provide surface preparation and recoat all interior and exterior repair areas and areas damaged as a result of repairs in accordance with Tab G - Coating Requirements. When welding on the shell or roof, the coating on the opposite side from the weld shall be inspected and repaired if damaged.
17. The existing gauge tubes were evaluated for compliance with the DESC/DLA Memorandum and UFC 3-460-01. Refer to “Additional Discussion Item – Gauge Tubes” for further commentary. The following is recommended:
• Continue to use one of the gauge tubes for the ENRAF ATG displacer. A waiver may be required since the tube is not fully slotted.
• Use the second existing gauge tube for the water/temperature probe. It should be noted that the gauge tube is not located near the low point sump.
• Use the gauge tube containing the displacer for the ENRAF ATG for manual gauging.
The displacer would have to be retracted each time.
• Note: These recommendations must be validated by DLA-E.
Assessment of Compliance with Current Military Criteria
The following recommended repairs are in accordance with UFC 3-460-01, Table 8-1, and Chapter 12, §12.3:
Table 8-1 of UFC 3-460-01 (Aug 2010 issue) describes appurtenances for vertical aboveground storage tanks.
1. Tank 15 is not equipped with item (c) a manhole located above the internal floating pan’s high position.
• EEI does not recommend installing an additional manhole.
2. Tank 15 is not equipped with item (e) four 24 inch square inspection hatches.
• EEI does not recommend installing additional inspection hatches.
Tank 15 – API 653 Inspection Page 6
EEI Project No.: 10-5632
3. Tank 15 is not equipped with item (f) two 36 inch shell manholes.
• The tank is equipped with two 28 inch manholes. There is no compelling reason to upsize the shell manholes.
4. Tank 15 is not equipped with item (r) one 8 inch gauge hatch for water bottom sampling as close to the center as possible.
• Refer to “Gauge Tube Assessment” for additional discussion.
Recommended Repairs for Long Term Serviceability
1. Program the tank for an API external in-service inspection in 5 years and an API out-of-service internal inspection no later than August 2031.
2. Test all level alarms and switches as part of on-going maintenance.
COATING SYSTEM
Interior and Exterior Coating Requirements
Refer to Appendix G for complete coating materials and application requirements for type and location of coating repair items identified by the inspection.
Out of Service Concerns
Tank 15 is currently out-of-service awaiting repairs. At the time of the inspection, the floor was found in good condition. It should be noted that degradation of the coating system may occur the longer the tank remains out-of-service. This can be attributed to possible original application defects such as incorrect surface profile preparation or insufficient removal of chlorides with potable water between coats. All of these potential defects could result in stress points and cracking during extreme temperature changes.
Inter-layer chloride contaminants, if present, will absorb water from moist air and swell. The coating is generally protected from temperature changes and contact with moist air by immersion in product, thus it may appear to exhibit certain characteristics when first cleaned but degrade over time.
SUITABILITY FOR SERVICE EVALUATION
Corrosion Rates
Corrosion rates for the tank floor, shell and roof were calculated using assumed nominal metal thicknesses when the tank was constructed in 1952. The corrosion calculations are also based upon the plate thickness obtained from UT thickness measurements at the time of the inspection.
The corrosion rates are summarized as follows:
Floor: 0.001047 inches per year Shell: Negligible – Plate thickness is within mill tolerance Roof: 0.000260 inches per year Based on the current corrosion rates, the useful life of the tank will exceed a 20 year inspection interval.
Tank 15 – API 653 Inspection Page 7
EEI Project No.: 10-5632
Tank Floor Corrosion Rates
The tank floor coating, with an average thickness of 14.0 mils, is a thin-film liner. For tanks with coated floors, API 653 permits a product side corrosion rate (StPr) of 0.00 in/yr. The coating was found to be in good condition with no topside pits identified as requiring repair.
StPr = 0.00 in/yr was used in the corrosion calculations.
Bottom side corrosion with small volumetric metal loss may be present and not detected by MFL scanning. The metal loss used to calculate the bottom side corrosion rate (Upr) was conservatively calculated using the average thickness of the floor minus a 20% threshold value for undetected bottom side pits. The MFL floor scanner is not setup to indicate (alarm) for minor metal loss.
The minimum remaining floor thickness (MRT) used in the calculations is based on API 653 Section 4.4.5 and Table 4.4. The tank has been equipped with the means to detect and contain a bottom leak. Based on this information, the MRT used in the calculations is 0.100 inch.
It was found that the floor plate thickness will not be reduced below the limiting MRT at a 20 year inspection interval.
Hydraulic and Structural Integrity
The following table summarizes the hydraulic and structural integrity of Tank 15:
HYDRAULIC AND STRUCTURAL INTEGRITY
Evaluation Item
Findings Comments
Foundation Tank 15 sits on a concrete ringwall. The tank passes API 653 criteria for levelness and differential settlement.
Acceptable
Floor Visual inspection of the floor joints found no relevant indications. MFL scanning of the tank floor found no relevant indications of corrosion on the bottom side of the floor. A pit survey was conducted for topside corrosion and no pits were identified requiring repair.
No localized bulges or depressions of the floor were found during the inspection.
Based upon the calculated corrosion rate, the floor plate thickness will not be reduced below the requirements for minimum floor plate thickness of 0.100 inch at a 20 year inspection interval.
Acceptable
Shell The inspection found no indications of damage or deterioration to the shell.
Acceptable
Roof The underside of the roof and roof structure appears sound with no significant indications or problems requiring repair. Inspection of the topside found no indications of damage or deterioration.
Acceptable
Internal Fluid Pressure
Hoop stresses by internal fluid pressure pass API 653 criteria.
Acceptable
Tank 15 – API 653 Inspection Page 8
EEI Project No.: 10-5632
HYDRAULIC AND STRUCTURAL INTEGRITY
Evaluation Item
Findings Comments
Hydrostatic Test
Shell is adequate to resist the internal fluid pressure caused by a full height hydrostatic test with water.
Acceptable
Brittle Fracture The API 653, Section 5, Figure 5.1, Brittle Fracture Considerations has been evaluated with the following findings:
1. Does the tank meet API 650(7th edition or later, 1980): No, constructed in 1952.
2. Has a prior hydrotest been performed demonstrating fitness: Unknow, but likely with installation of new floor.
3. Is the tank shell thickness < 0.5 inch: Yes.
4. Does the tank operate at metal temperature above 60 deg F?: No.
5. Is the tank membrane stress below 7 ksi?: No.
6. Tank steel exempt per API 650, Figure 4-1 or API
653 Figure 5.2: Yes.
7. Tank full at lowest one day temperature per API 650
Figure 2.2: Unknown.
The tank, having a thickness less than 0.5 inches and steel exemption per Figure 5.2, does not fit the API 653 at-risk profile for brittle fracture failure.
Seismic Evaluation
Seismic calculations were performed in accordance with API 650 Appendix E. It was found that the tank is considered stable against overturning and longitudinal stresses are acceptable at the current fill height.
Calculations were performed utilizing the specific gravity for JP-8 (S.G. = 0.84), a ringwall foundation, seismic parameters Ss = 1.06, S1 = 0.29, an importance factor of 1.0.
Acceptable
Wind Evaluation
A wind analysis was performed per API 650, Section 5.11.
Calculations were performed using an importance factor of
1.0 and a wind velocity of 90 mph.
The tank is not anchored. The evaluation determined that an empty unanchored tank is not at risk of overturning or sliding.
Evaluation of the shell buckling determined that the shell is adequate, without stiffeners, for wind speeds in excess of 90 mph.
Acceptable
ADDITIONAL DISCUSSION ITEM
Gauge Tubes
The requirements for stilling wells have been reviewed. These requirements are based on the DESC Memorandum “Automated Tank Gauge (ATG) Installation Policy” of December 2009.
The comments below represent concept solutions based on the memorandum. It is recommended that the concept be submitted to DESC for ratification or redirection. Field verification of constructability by the prime contractor is also recommended.
Tank 15 – API 653 Inspection Page 9
EEI Project No.: 10-5632
Tank 15 Existing Conditions
Tank 15 is an AST with a cone-down floor with a near center sump and a floating pan. The tank is equipped with two 8 inch aluminum gauge tubes. One gauge tube, located 11 feet from the shell, contains the displacer and temperature probe for the ENRAF ATG system. The other gauge tube, located 7 feet from the shell, is used for manual gauging. The slots in both gauge tubes are limited to the lower 40 inches of the tubes.
Gauge Tube Recommendations
The following are recommended for compliance with the DESC/DLA Memorandum (for ATG) and UFC 3-460-01 (for operations):
1. Continue to use one of the gauge tubes for the ENRAF ATG displacer (DLA directive). A waiver may be required since the tube is not fully slotted.
2. Use the second existing gauge tube for the water/temperature probe (DLA directive). It should be noted that the gauge tube is not located near the low point sump. If it is desired to provide the water probe over the low point, it will be necessary to provide a new roof nozzle, a 6 inch slotted aluminum gauge tube and a new penetration in the floating pan. The roof nozzle and gauge tube would have to be fitted between roof framing members. The issue piping, low fuel piping and water draw-off piping, currently located above the low point sump, would require re-working.
3. Use the gauge tube containing the displacer for the ENRAF ATG for manual gauging (UFC criteria). The displacer would have to be retracted.
Note: These recommendations must be validated by DLA-E.
CLOSURE
Conclusions
Based on the extent of this inspection, Tank 15 is suitable to return to service.
Project Team
Site Team
David A. Stchyrba, P.E. Structural Engineer, API 653 Aboveground Storage Tank Inspector Certificate No. 27187, API Inspector of Record.
Todd Lichtenberg Sr. NDE Technician, Level II Inspector
Mike Lawrence Tank Technician
Support Team
Stacy M. Kaplan-McMillan Project Manager
Stephen S. Brooks, P.E. Technical Advisor, QA Review, API 653 Aboveground Storage Tank Inspector Certificate No. 17.
APPENDIX A
Tank Inspection Data Sheet and Evaluation Items
APPENDIX A AST Tank Inspection Data Sheet Tank 15 – API 653 Inspection October 2011 EEI Project No.: 10-5632
DLA-E TANK CMP CONDITION FORM
TANK INSPECTION SUMMARY SHEET
Tank Location E-2 Fuels Complex, Eielson Air Force Base, Alaska Tank No. 15
Facility No. 6239 Inspection Date(s): August 15, 2011
Tank Type: Vertical AST Type of Inspection: Internal & External w/ Suitability for Service
Contract Number, Task Order: FA8903-08-D-8770 Prime Contractor Name: AECOM Inspector, Certificate #: David A. Stchyrba, P.E.
API-653 AST Inspector Certificate No. 27187
Inspection Company: Enterprise Engineering, Inc.
2525 Gambell Street, Suite 200 Anchorage, AK 99503
(907) 563-3835
Manufacturer, Date, Design Standard Original: Unknown, 1952, API Standard 12C New Floor: Morse Construction, 1998, API 653 2nd Edition
Diameter: 60'-0" Shell Height: 31’ – 8½"
Product, Specific Gravity: JP-8, 0.84 Design Pressure / Temperature: Unknown
Gross Capacity / Nominal Capacity: 15,000 Bbls / 14,723 Bbls Safe Fill Height: 26' – 6-1/8” (Elevation of overflow ports)
GPS Latitude & Longitude: 64 Deg 39’ 35.81” N, 147 Deg 03’ 21.56” W (Source – Google Earth)
Foundation Configuration: Concrete Ringwall Shell Configuration: Butt Welded w/ 5 courses (Add’l info enclosed) Floor Configuration: Cone down w/ lap welded plates oriented in rows with center sump (Add’l info enclosed) Roof: Column supported roof (Add’l info enclosed)
Cathodic Protection: None present Still Wells: Two present (Add’l info enclosed)
Last Inspection (Type, Date): In-Service, September 2009 Last Coated Internally (Product): 1998, Devoe Coatings (specific product unknown)
Last Coated Externally (Product): 1998, Devoe Coatings (specific product unknown)
INSPECTION RESULTS
Can tank be returned to service? Yes, following mandatory repairs.
Deficiencies identified as mandatory repairs: No. (See paragraph titled “Repair Items” in body of report)
Deficiencies identified as recommended repairs:
Yes. (See paragraph titled “Repair Items” in body of report)
Deficiencies identified as long term repairs: Yes. (See paragraph titled “Repair Items” in body of report) Next Scheduled Inspections (Type, Date:) In-Service: August 2016 (5 Years)
Out-of-Service: August 2031 (20 Years)
ADDITIONAL ITEMS
Change in Service: None As-Built Drawings, Specifications: Not available
APPENDIX A AST Evaluation Items - TOC Tank 15 – API 653 Inspection October 2011 EEI Project No.: 10-5632
AST EVALUATION ITEMS
TABLE OF CONTENTS
PAGE
FOUNDATION
FLOOR
SHELL
ROOF
INTERNAL FLOATING PAN
COATINGS
APPURTENANCES
PIPING
APPENDIX A - AST Evaluation Items Page 1 Tank 15 – API 653 Inspection October 2011
FOUNDATION
Evaluation Item Finding(s) Comments/Recommendations
(A blank in comments column indicates lack of significance, or condition is acceptable.)
FOUNDATION
Type Tank 15 rests on a concrete ring wall.
Levelness Tank 15 is relatively level. The maximum measured differential between max and min elevations is
0.04 feet.
Tank 15 passes API 653 criteria for levelness and differential settlement.
Rigid Body Tilt Tank 15 is slightly tilted. The amount of tilt is 0.02 inches.
Amount of tilt is within acceptable limits.
Height Above Dike Floor The concrete ringwall is approximately 16 inches above the dike floor.
Material Below Tank Floor The material below the tank floor could not be inspected.
Drainage Around Tank Drainage around the tank appears to be adequate.
Tank Anchors Tank 15 is not equipped with anchors.
Secondary Containment Tank 15 sits within an earthen dike with a membrane liner.
Settlement Tank 15 rests on a concrete ringwall. No concern.
Erosion/Washouts No indications of washouts or erosion were observed.
Sealed at Foundation The sealant between the tank floor projection and the concrete ringwall is failing.
Recommend removing the sealant from the tank perimeter. Clean, prep surfaces and provide new jet fuel resistant sealant.
Additional Foundation Items, Comments or Notes:
None.
APPENDIX A - AST Evaluation Items Page 2 Tank 15 – API 653 Inspection October 2011
FLOOR
(A blank in comments column indicates lack of significance, or condition is acceptable.)
TANK FLOOR
Type Lap welded steel floor plates in a cone down arrangement.
Nominal Thickness The floor consists of 5/16 (0.3125) inch thick floor plates.
Annular Ring Plates Tank 15 is not equipped with an annular ring.
Thickness The average thickness of the interior floor plates is 0.309 inches. The exterior floor projection has an average thickness of 0.311 inches.
Interior Width The floor plate width is approximately 8 feet.
Floor seam welds Visual inspection of the floor seam welds found no significant indications requiring further inspection.
MFL Floor Scan MFL scan of the accessible areas of the floor found no indications requiring UT prove-up.
Bottom Side Floor Pitting/Corrosion
Based on MFL and UT examination, bottom side pitting/corrosion is not prevalent.
Top Side Floor Pitting/Corrosion
The floor is coated. No pitting was observed.
Patch Plates No lapped patch plates were observed on the floor.
Oil Canning/Flexing No significant flexing of floor plates was
Edge Settlement Edge settlement was not noted.
Measurements taken for edge settlement at 8 equidistant locations pass API 653, Appendix B criteria.
Floor Bulges, Depressions No significant bulges or depressions were noted.
Doubler/Support Plates Doubler plates are present below each of the floating pan legs. The plates consist of light gauge stainless steel that has been attached to the floor with epoxy.
Plug Welds No plug welds were observed.
APPENDIX A - AST Evaluation Items Page 3 Tank 15 – API 653 Inspection October 2011
FLOOR
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Weld Artifacts No weld artifacts were noted.
Vacuum Box Testing Vacuum box testing was not performed. The tank floor is coated and no suspect areas were noted.
Helium Leak Testing HLT not performed.
Floor Critical Zone No corrosion or deflection was observed within the critical zone.
Floor Profile The floor is cone down with one near center sump. The tank floor has a 6.60% slope to the sump.
Sumps Tank 15 has one 40 inch diameter sump. Wall thickness is 0.370 inches (UT) and bottom thickness is 0.356 inches (UT).
Leak Detection Below Floor There are no leak detection ports extending through the ringwall. The extent of the piping connected to the leak detection standpipes is unknown.
Leak Detection Standpipe Tank 15 is equipped with two leak detection standpipes. Water was observed in the bottom of each pipe. A sheen was also visible and a hydrocarbon odor was detected.
Recommend draining the fluid from the standpipes and test for the presence of hydrocarbons.
Cathodic Protection Below Floor
Tank 15 is not equipped with a cathodic protection system.
Additional Floor Items, Comments, Notes:
APPENDIX A - AST Evaluation Items Page 4 Tank 15 – API 653 Inspection October 2011
SHELL
(A blank in comments column indicates lack of significance, or condition is acceptable.)
TANK SHELL
Nominal Thickness UT Thickness Coating
1st Course 0.268 inch 24.4 mils
2nd Course 0.278 inch 21.9 mils
3rd Course 0.253 inch 25.7 mils
4th Course 0.253 inch 26.5 mils
5th Course 0.246 inch 20.9 mils
Rim Angle 0.308 inch
Plumbness Visual observations found tank is not out-of-plumb.
Roundness The tank was measured across two diagonal locations with no out-of-roundness noted.
Dents/Buckles Minor bulges/depressions were observed in the 1st shell course. The defects have been attributed to the relocation of the tank to its current site.
The operators report that the floating pan cannot be set at its low leg position because it will hang up on the defects.
No repair is recommended at this time.
Monitor the defects as part of routine maintenance.
Banding/Peaking No significant banding or peaking was
Interior Shell pitting/corrosion No pits or corrosion were observed on the interior shell courses.
Exterior Shell pitting/corrosion No significant pits or corrosion were observed on the exterior shell courses.
Door sheet No door sheets were observed.
Welded Patch Plates No welded patch plates were observed on the exterior or interior shell surfaces.
Insert plates An insert plate 24 inches tall x 60 inches long was observed in the 1st shell course.
Interior Shell Welds Visual inspection of accessible interior shell welds found no indications for further inspections or examinations.
Exterior Shell Welds Visual inspection of accessible exterior shell welds found no indications for
APPENDIX A - AST Evaluation Items Page 5 Tank 15 – API 653 Inspection October 2011
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Shell-to Floor Weld – Interior Visual inspection of the interior shell-to-bottom welds found no indications for
Shell-to Floor Weld – Exterior Visual inspection of the exterior shell-to-floor welds found no indications for
Shell Manways The tank is equipped with two first course shell manways.
Shell Reinforcing Plates
Manways
(Size, Thickness, Telltale Hole)
28 inch nozzle, 0.574 inch thick neck
(UT).
Manway #1
Diamond reinforcing plate 64 inches wide x 52 inches tall and 0.621 inches thick (UT).
The telltale hole in the reinforcing plate is open.
Recommend packing the hole with general purpose grease to prevent moisture migration between the reinforcing plate and the shell.
28 inch nozzle, 0.572 inch thick neck
(UT).
Manway #2
Diamond reinforcing plate 64 inches wide x 52 inches tall and 0.615 inches thick (UT).
The telltale hole in the reinforcing plate is open.
Recommend packing the hole with general purpose grease to prevent
Receipt/Fill
(Size, Thickness, Telltale Hole)
8 inch nozzle, 0.489 inches thick neck
(UT).
Circular reinforcing plate 19 inches side and 0.312 inches thick (UT). The telltale hole in the reinforcing plate is open.
Recommend packing the hole with general purpose grease to prevent
Issue/Service
Hole)
8 inch nozzle, 0.486 inch thick neck
(UT).
Circular reinforcing plate 19 inches wide and 0.318 inch thick (UT). The telltale hole in the reinforcing plate is open.
Recommend packing the hole with general purpose grease to prevent
APPENDIX A - AST Evaluation Items Page 6 Tank 15 – API 653 Inspection October 2011
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Low Fuel Draw-Off
(Size, Thickness, Telltale Hole)
4 inch nozzle, 0.346 inch thick neck
(UT).
Circular reinforcing plate 11½ inches wide and 0.311 inches thick (UT). The telltale hole in the reinforcing plate is open.
Recommend packing the hole with general purpose grease to prevent
Water Draw-Off
Hole)
3 inch nozzle, 0.316 inch thick neck
(UT).
Tombstone reinforcing plate 10½ inches wide x 17 inches tall and 0.310 inches thick (UT). The telltale hole in the reinforcing plate is open.
Recommend packing the hole with general purpose grease to prevent
Low Level Alarm Nozzle (Upper)
(Size, Thickness, Telltale Hole)
2 inch nozzle, 0.236 inch thick neck
(UT).
A reinforcing plate is not present.
A reinforcing plate is not required.
Low Level Alarm Nozzle (Lower)
(Size, Thickness, Telltale Hole)
2 inch nozzle, 0.239 inch thick neck
(UT).
A reinforcing plate is not present.
A reinforcing plate is not required.
Shell Vents Tank 15 is not equipped with shell vents.
Overflow Ports The tank is equipped with 6 overlfow ports. A screen is present at the opening in the shell but not at the opening in the underside of the port. A significant number of bird nests were observed within the ports. Plugged screens will affect the tanks ability to breathe during filling and emptying operations.
Recommend removing all of the bird screens and providing a bird/insect screen at the underside of each port.
Wind Girders and Shell Stiffeners (Size & Elevation)
Tank 15 is not equipped with a wind girder or shell stiffener.
Tank Nameplate Data:
Repaired/Altered to API 653 2nd Edition Altered by: Morse Construction Group Inc., Rockford Corporation Morse Job No. 2230-EI-5807 Year Altered: 1998 Inserts: A131CS Nominal Diameter: 60 ft Nominal Height: 31’-8½” Capacity: 616,403 Gallons Maximum Liquid Level 28’-5” Design Specific Gravity: JP-8 Original Standard: 12-C Original Construction Date: 1952
APPENDIX A - AST Evaluation Items Page 7 Tank 15 – API 653 Inspection October 2011
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Secondary Nameplate:
Horton Tank Chicago Bridge & Iron Co.
Year: 1952 Diameter: 60 ft Height: 32 ft Nominal Capacity: 16,000 bbls
Additional Shell Items, Comments or Notes:
APPENDIX A - AST Evaluation Items Page 8 Tank 15 – API 653 Inspection October 2011
ROOF
(A blank in comments column indicates lack of significance, or condition is acceptable.)
TANK ROOF
Type Fixed cone steel roof with lap welded roof plates.
Roof Plate Thickness The roof consists of 3/16 inch (0.1875 inch) thick plates. Average thickness
0.191 inches (UT).
Roof Topside pitting/corrosion No pitting was identified on the topside of the roof.
Roof Bulges/Depressions No significant bulges or depressions were identified. No water ponding areas were observed.
Roof Joints Roof plates are lap welded on the exterior of the roof. Visual inspection of roof topside welds found no significant indications requiring further examination.
Frangible Joint (Size/Condition) Tank 15 is equipped with a frangible joint.
Roof Vents (Size & Type) The tank is equipped with an 8 inch gooseneck style atmospheric vent.
The vent opening is not equipped with a screen.
Two 10 pressure/vacuum vents are present on the roof. However, the pallets have been removed so they function only as atmospheric vents.
Recommend providing a bird/insect screen at the vent opening.
Roof Manways The tank is equipped with one 24 inch and one 36 inch manway. The 36 inch manway is located above the combination ladder/gauge tube.
Roof Hatches The tank is equipped with one 3 foot x 6 foot construction hatch. Coating failure and minor corrosion on the hatch.
Recommend removing coating from affected areas, clean and recoat.
Roof Nozzles Additional nozzles include four 2 ½ inch nozzles with threaded caps and a 12 inch nozzle. The 12 nozzle contains the displacer and temperature probe for the ENRAF ATG.
APPENDIX A - AST Evaluation Items Page 9 Tank 15 – API 653 Inspection October 2011
ROOF
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Gauge Hatch The tank is equipped with an 8 inch hatch for manual gauging. Only two bolts are present in the flange.
Recommend providing the remaining missing bolts.
Handrails The tank roof is equipped with a perimeter handrail.
Roof Access from Ground Roof access is by spiral stairs.
Roof Access to Adjacent Tank None.
Roof Framing / Roof Underside Condition
The interior roof structure appears to be in good condition with no twisting or bending of components. The interior roof framing was evaluated visually from the floating pan with no indications for further examination.
Roof Patch Plates No patch plates were observed on the roof of Tank 15.
Roof Elevation The center of the cone roof is raised above the shell elevation.
Interior Columns The tank is equipped with a single built-up channel column including a frame and base plate. The base plate is welded to the floor. The frame is not welded to the plate. Lateral movement of the frame is limited by restraint angles.
Additional Roof Items, Comments or Notes:
APPENDIX A - AST Evaluation Items Page 10 Tank 15 – API 653 Inspection October 2011
INTERNAL FLOATING PAN
(A blank in comments column indicates lack of significance, or condition is acceptable.)
FLOATING ROOF
Material Type Aluminum honeycomb floating pan.
Primary Seal Type The floating pan is equipped with a primary (lower) wiper seal. The wiper has folded under at several locations.
Recommend manually readjusting the wiper seal so that it is correctly oriented.
Secondary Seal Type The floating pan is equipped with a secondary (upper) wiper seal. The wiper has folded under at several locations.
Recommend manually readjusting the wiper seal so that it is correctly oriented.
Vacuum Breaker The floating pan is equipped with one vacuum breaker.
Roof Access – Ladder to roof The tank is equipped with a combination ladder/gauge tube.
Leg Supports The floating roof is equipped with 15 support legs. The tank floor is equipped with a striker plate below each leg.
Anti-Rotation Method The floating roof is equipped with one anti-rotation cable that extends from roof to floor.
Roof Grounding The floating pan is equipped with two grounds.
Appurtenance Seals The seals at the center column, gauge tube and combination ladder/gauge tube have deteriorated.
Recommend replacing the seals.
Additional Floating Roof Items, Comments or Notes:
APPENDIX A - AST Evaluation Items Page 11 Tank 15 – API 653 Inspection October 2011
COATINGS
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Exterior Coatings
Shell
Type/age Epoxy coating system. It was reported that the coating was installed in 1998.
General Condition The exterior coating is in satisfactory condition.
Isolated Conditions Minor areas with coating failure and corrosion were observed on the shell appurtenances.
Recommend removing the coating from the affected areas, clean, prep and coat.
Nominal Thickness The average thickness of the shell coating for all 5 courses is 23.9 mils;
with a maximum thickness of 31.9 mils and a minimum thickness of 14.8 mils.
Roof
General Condition The exterior coating is in satisfactory condition.
Isolated Conditions Approximately 10 square feet of localized coating failure was observed on the tank roof. Minor areas with coating failure and corrosion were observed on the roof appurtenances.
Recommend removing the coating from the affected areas, clean, prep and coat.
Nominal Thickness The average thickness of the coating is
21.9 mils; with a maximum thickness of
32.2 mils and a minimum thickness of
14.8 mils.
Interior Coatings
Floor
General Condition The coating is stained but in satisfactory condition.
Isolated Conditions Approximately 16 square feet of localized coating failures were observed on the floor of Tank 15.
Recommend removing the coating from the affected areas, clean, prep and coat.
APPENDIX A - AST Evaluation Items Page 12 Tank 15 – API 653 Inspection October 2011
COATINGS
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Nominal Thickness The average thickness of the coating is
14.0 mils; with a maximum thickness of
29.8 mils and a minimum thickness of
7.5 mils.
Shell
General Condition In general, the interior coating is in good condition with good adherence.
Isolated Conditions No localized areas of coating failure
Nominal Thickness The average thickness of the coating is
20.2 mils; with a range of 11.9 to 29.4 mils.
Underside Roof
General Condition In general, the interior coating is in good condition with good adherence.
Isolated Conditions No localized areas of coating failure
Nominal Thickness Unable to access underside of roof.
Additional Coating Items, Comments or Notes:
APPENDIX A - AST Evaluation Items Page 13 Tank 15 – API 653 Inspection October 2011
APPURTENANCES
(A blank in comments column indicates lack of significance, or condition is acceptable.)
APPURTENANCES
Float Gauge Tank 15 is equipped with a Varec tape gauge. Water was observed in the tape gauge display.
Recommend providing a new tape gauge system.
ATG (Automatic Tank Gauging) or RTG (Remote Tank Gauging) System
Tank 15 has an ENRAF ATG. The displacer and temperature probe for the ATG system are located within an 8 inch aluminum gauge tube.
HI/HI-HI Level Alarms The HI and HI-HI level alarms are incorporated as part of the ENRAF ATG system. Alarm points of 26 feet 7 inches and 28 feet 0 inches are built into the software program that is connected to the POL office.
Low Level Alarms The LOW level alarm is incorporated as part of the ENRAF ATG system. Alarm set point is 1 foot 8 inches.
High Level Shut-Off Valve Float
Tank 15 is equipped with a high level shut-off valve. The float for the valve is located on the tank shell. The set point is 27 feet 5 inches.
Independent Level Alarm Tank 15 is equipped with an independent HI-HI and HI level alarm system.
Gauge Tube – Sampling/Testing/Hand Gauging
Manual gauging occurs at the 8 inch gauge hatch located in the roof manway.
Datum Plate on Floor A datum plates was observed within the combination ladder/gauge tube.
Tank Grounding The tank is grounded.
Fire Suppression System The tank is equipped with a fire suppression system.
Product Recovery Tank Tank 15 is equipped with a product recovery tank connected to the water draw-off piping. Corrosion and coating failure was observed on the tank.
Recommend removing the coating from the affected areas, clean, prep and coat.
Additional Appurtenance Items, Comments or Notes:
APPENDIX A - AST Evaluation Items Page 14 Tank 15 – API 653 Inspection October 2011
PIPING
(A blank in comments column indicates lack of significance, or condition is acceptable.)
PIPING
Fill / Receipt / Piping
Interior Piping, Size, Type, UT The interior fill piping consists of an 8 inch pipe extending inward from the shell and includes a diffuser. UT thickness of the pipe is 0.492 inches.
Valve (Type/Condition) 8 inch steel, Class 150, General Twin Seal DB&B plug valve with gear actuator. Corrosion and coating failure were observed on the valve.
Recommend removing the coating from the affected areas, clean and recoat.
Pressure Relief Piping The pressure relief loop is equipped with two ¼ turn ball valves for isolation and testing.
High Level Shut-Off Valve
(Type/Condition)
8 inch, 150 lb class, Clav-Val high level shut-off valve (HLV). The valve is operated by an auto level shut-off valve float located on 5th shell course.
Stainless steel pilot tubing extends from the float to the valve.
Issue Piping
Interior Piping, Size, Type, UT The interior Issue piping consists of a 8 inch pipe that extends above the sump.
UT thickness of the pipe is 0.491 inches.
Valve (Type/Condition) 8 inch steel, Class 150, General Twin Seal DB&B plug valve with gear actuator. Corrosion and coating failure were observed on the valve.
Recommend removing the coating from the affected areas, clean and recoat.
Pressure Relief Piping The pressure relief loop is equipped with two ball valves for isolation and testing.
Sump / Water Draw-Off
Interior Piping, Size, Type, UT The interior water draw-off piping consists of a 3 inch pipe that reduces to 1½ inches and extends into the sump.
UT thickness of the pipe is 0.304 inches.
APPENDIX A - AST Evaluation Items Page 15 Tank 15 – API 653 Inspection October 2011
PIPING
(A blank in comments column indicates lack of significance, or condition is acceptable.)
Valve (Type/Condition) 3 inch, 150 lb class, General Twin Seal DB&B plug valve with manual operator.
Corrosion and coating failure were observed on the valve.
Unprotected hydraulic tubing is protected at the valve.
Recommend removing the coating from the affected areas, clean and recoat
Recommend providing an ice/snow shield above the hydraulic tubing.
Low Fuel Draw-Off
Interior Piping, Size, Type, UT The interior low fuel draw-off piping consists of a 4 inch pipe that extends into the sump. UT thickness of the pipe is 0.342 inches.
Valve (Type/Condition) 4 inch, 150 lb class, General Twin Seal DB&B plug valve with gear operator.
Corrosion and coating failure were observed on the valve.
Recommend removing the coating from the affected areas, clean and recoat.
Additional Piping Items, Comments or Notes:
END OF…
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