Attachment K.1 WPN-FY20-FAC 7052-Tank 255-FINAL.pdf

US Army Corps of Engineers Omaha District

API 653 In-Service Inspection Report

Wright-Patterson Air Force Base Tank 255

Facility 7052

US Army Corps of Engineers Center of Expertise for Petroleum, Oils and Lubricants

(USACE POL-MCX)

10/8/2020

API 653 Inspection Report Wright-Patterson AFB, Ohio

TABLE OF CONTENTS

GENERAL SUMMARY

INSPECTION DATE

STATE REGULATIONS

PREVIOUS INSPECTION DATES

RECOMMENDED FUTURE INSPECTION DATES

GENERAL TANK INFORMATION

A. GENERAL PROJECT INFORMATION

1. API 653 IN-SERVICE (EXTERNAL) INSPECTION

2. SITE INFORMATION

B. TANK INSPECTION COMMENTS

1. TANK CONSTRUCTION

2. TANK FOUNDATION

3. CATHODIC PROTECTION

4. TANK SHELL

5. GEODESIC DOME ROOF

6. INTERNAL FLOATING ROOF

7. TANK APPURTENANCES

8. TANK AND PIPING COATING

9. TANK PIPING SYSTEM

10. FIRE PROTECTION SYSTEM

11. SECONDARY CONTAINMENT

C. FINDINGS AND RECOMMENDATIONS

1. MANDATORY REPAIRS PER API 650/653, UFC 3-460-01/3-460-03, OR DoD AW 78-24-27

2. SHORT-TERM RECOMMENDED REPAIRS

3. LONG-TERM RECOMMENDED REPAIRS

APPENDIX A: ENGINEERING CALCULATIONS AND DRAWINGS

NEXT INSPECTION

API/OSHA ACCESS STRUCTURE REPORT

APPENDIX B: API 653 CHECKLISTS FOR TANK INSPECTIONS

APPENDIX C: PHOTOGRAPHS

ACRONYMS AND ABBREVIATIONS

AFB Air Force Base

AFFF Aqueous Film Forming Foam

API American Petroleum Institute

ATG Automatic Tank Gauge

BBL Barrel

BMP Best Management Practice

CP Cathodic Protection

DB&B Double Block and Bleed

DFT Dry Film Thickness

DoD Department of Defense

FML Flexible Membrane Liner

HHLA High-High Level Alarm

HLA High Level Alarm

HLCV High Level Control Valve

IAW In Accordance With

ICCP Impressed Current Cathodic Protection

IFR Internal Floating Roof

LLA Low Level Alarm

LLLA Low-Low Level Alarm

NDT Non-Destructive Testing

NFPA National Fire Protection Association

OOS Out-of-Service

OSHA Occupational Safety and Health Administration

PST Product Saver Tank

TLG Tape Level Gauge

TRV Thermal Relief Valve

UFC Unified Facilities Criteria

USACE United States Army Corps of Engineers

UTT Ultrasonic Thickness Testing

VT Visual Testing

GENERAL SUMMARY

Pond was retained by the United States Army Corps of Engineers (USACE) to provide an in-service tank inspection for Tank 255 (Facility 7052) at Wright-Patterson Air Force Base (AFB) in Dayton, Ohio.

The in-service inspection was performed 7-8 October 2020. Results of this inspection identified recommended repairs/upgrades to fully comply with applicable sections of American Petroleum Institute (API) 650/653, Unified

Facilities Criteria (UFC) 3-460-01/3-460-03, Department of Defense (DoD) Standard Design AW 78-24-27, National

Fire Protection Association (NFPA) 407, best management practices (BMP), and industry standards.

Tank 255 is a welded, steel, vertical, aboveground Jet-A storage tank. The tank was constructed by Chicago Bridge and Iron Company in 1952 and is assumed to be built to API 12C standards. The tank was repaired to API 653, 3rd edition by Toltest, Inc. in 2005 and repaired again to API 653 by Cape in 2009. The tank is 42’-6” in diameter and

42’-0” high with a nominal capacity of 10,620 barrels (BBL) (446,040 gallons). The bulk fuel storage area at Wright-

Patterson AFB consists of eleven (11) storage tanks. According to facility personnel, three (3) tanks are in service, and eight (8) are out of service and scheduled for demolition. Tank 255 is currently in-service and scheduled to be one (1) of the three (3) tanks to remain.

Testing and inspection activities were performed in accordance with (IAW) applicable sections of API 653, 5th

Edition. This report contains a detailed account of the tank inspection, non-destructive testing (NDT) methods, and conclusions derived from the inspection and testing activities. Findings from this inspection are further detailed in

Section B – Tank Inspection Comments. Recommended repairs and upgrades identified in Section B are further classified and listed in Section C – Findings and Recommendations.

INSPECTION DATE

API In-Service (External) Inspection Date: 8 October 2020 Equipment Used:

Manufacturer: GE Krautkramer Ultrasonic Thickness Gauge Model Number: DMS GO+ Calibration Method: One-Point Calibration

Manufacturer: Fischer Technologies Dry Film Thickness (DFT) Gauge Model Number: Dual Scope MPOR Calibration Method: Calibration to Known Thickness Standard

Manufacturer: Technidea Corporation Model Number: ZipLevel Pro 2000 Calibration Method: Manufacturer Calibrated

Inspector:

Andrew D. Morrissette

STATE REGULATIONS

State Regulation for API In-Service Tank Inspections: N/A State Regulation for API Out-of-Service Tank Inspections: N/A

PREVIOUS INSPECTION DATES

API Out-of-Service (OOS) (Internal) Inspection Date: August 2009 API In-Service (External) Inspection Date: July 2015

RECOMMENDED FUTURE INSPECTION DATES

API OOS (Internal) Inspection Date: August 2029* API In-Service (External) Inspection Date: October 2025 *OOS inspection date based on the previous in-service inspection report dated July 2015.

Andrew D. Morrissette Brian W. Lunsford

Mechanical Integrity Engineer Vice President | Asset Integrity

API 653 Inspector # 80109 API 653 Inspector # 28526

ASNT NDT Level II ASNT NDT Level II

GENERAL TANK INFORMATION

ITEM DESCRIPTION

Owner US Air Force

Location Wright-Patterson Air Force Base

Facility Number 7052

Tank Number Tank 255

State / Country Ohio, USA

City Dayton

Inspection Date 8 October 2020

Tank Manufacturer Chicago Bridge & Iron Company (Original) Toltest, Inc. and Cape (Repair/Alteration)

Design Standard API 12C (Assumed) API 653 (Repair/Alteration)

Date of Construction 1952

Tank Contents Jet-A

Tank Diameter 42’-6”

Shell Height 42-0”

Tank Capacity 10,620 BBL (446,040 gallons)

Foundation Concrete Ring Wall

Construction

Bottom: Lap-Welded(1)

Shell: Butt-Welded / Seven (7) Shell Courses

Fixed Roof: Geodesic Dome

Floating Roof: Lap-Welded / Double Wiper Peripheral Seals

Material

Bottom: Carbon Steel(1)

Shell: A36 Carbon Steel

Fixed Roof: Aluminum

Floating Roof: Carbon Steel

Cathodic Protection (CP) Impressed Current Cathodic Protection (ICCP) System

Interior Coating System Unknown

Exterior Coating System Epoxy with Polyurethane Topcoat (Assumed)

Level Gauging Enraf Automatic Tank Gauge (ATG) Varec Tape Level Gauge (TLG)

Overfill Protection High Level Alarm (HLA) / High-Level Control Valve (HLCV) Float Pilot

Piping

Receipt 6-inch Carbon Steel

Type III Return 8-inch Stainless Steel

Type III Issue 12-inch Stainless Steel

Fill Stand Issue/Transfer 8-inch Carbon Steel

Stripper 4-inch Carbon Steel

Water Draw-Off 3-inch Carbon Steel

Product Saver Tank (PST) Return

3-inch Carbon Steel

Aqueous Film Forming Foam (AFFF)

Carbon Steel

Level Alarms HLA and Low Level Alarm (LLA)

Notes:

(1) Based on previous in-service inspection report dated July 2015.

A. GENERAL PROJECT INFORMATION

1. API 653 IN-SERVICE (EXTERNAL) INSPECTION

The in-service inspection was performed 7-8 October 2020. Results of this inspection identified recommended repairs/upgrades to fully comply with applicable sections of API 650/653, UFC 3-460-

01/3-460-03, DoD Standard Design AW 78-24-27, NFPA 407, and industry standards.

2. SITE INFORMATION

Wright-Patterson AFB is headquarters for a vast, worldwide logistics system, a world-class laboratory research function, and is the foremost acquisition and development center in the U.S. Air Force. Dozens of associate organizations representing a broad spectrum of Air Force and Department of Defense activities call Wright-Patterson home. The base is comparable to a medium sized city with services ranging from shopping facilities and childcare centers to housing areas and a large medical center.

B. TANK INSPECTION COMMENTS

1. TANK CONSTRUCTION

Tank 255 is a welded, carbon steel, vertical, aboveground Jet-A storage tank. The tank was constructed by Chicago Bridge and Iron in 1952 and is assumed to be built to API 12C standards. The tank was repaired to API 653 by Toltest, Inc. in 2005 and Cape in 2009. The tank is 42’-6” in diameter and 40’-0” high with a nominal capacity of 10,000 BBL (420,000 gallons). The bulk fuel storage area at Wright-

Patterson AFB consists of eleven (11) storage tanks. According to facility personnel, three (3) tanks are in service, and eight (8) are out of service and scheduled for demolition. Tank 255 is currently in-service and scheduled to be one (1) of the three (3) tanks to remain.

2. TANK FOUNDATION

Tank 255 rests on a concrete ring wall foundation. The tank chime-to-foundation joint is provided a sealant along its entire circumference. Sealant is in good condition with no signs of damage or deterioration. Coating on the tank chime exhibits flaking and areas of base metal exposure with surface corrosion.

A settlement evaluation was performed during the inspection. The settlement evaluation does not satisfy

API 653 criteria; however, the settlement evaluation performed does not accurately represent tank settlement, as the small tank diameter results in a small arc length. No visual signs of excessive settlement were observed. Settlement should continue to be monitored during future inspections. See Appendix A for settlement results.

3. CATHODIC PROTECTION

Tank 255 is equipped with an ICCP system. According to the previous CP survey report dated February

2020, the deep well ground bed has been depleted. The deep well groundbed is scheduled to be replaced.

4. TANK SHELL

The tank shell is equipped with seven (7) fully coated, butt-welded, A36 carbon steel courses. Shell plates were examined using ultrasonic thickness testing (UTT) and visual testing (VT) methods. Nine (9) UTT measurements were taken on each plate of the 1st shell course. Ten (10) UTT measurements were taken on each of the 2nd through 7th shell courses using the spiral staircase for access. UTT measurements indicated no significant signs of metal loss on shell plates.

The tank shell is equipped with a wind girder on the 7th shell course, 3-feet from the top of the tank shell.

The external coating for the wind girder and tank shell exhibits widespread chalking, flaking, corrosion staining, and base metal exposure with surface corrosion.

Tubing for the receipt and Type III return HLCV float pilots is in contact with the tank shell. Contact point corrosion was observed at the time of inspection. One (1) angle iron support is welded at the vertical weld between shell plates 3-6 and 3-1. API mandates a minimum spacing of 6-inches between welded appurtenances and adjacent vertical shell welds. No visual signs of stress cracking were observed during the inspection. VT was limited due to the elevation of the angle iron.

Product designation labeling for Tank 255 exhibits fading and is no longer legible. The tank is not provided with an emergency responder diamond IAW NFPA 704.

Refer to Drawing A-1, “Shell Layout”, in Appendix A for shell plate locations and Table 1, “Shell UTT

Measurements”, in Appendix A for shell plate UTT measurements.

5. GEODESIC DOME ROOF

Tank 225 is provided an aluminum geodesic dome roof. The geodesic dome roof was examined using VT methods. According to facility personnel, the tank was previously an external floating roof that was retrofitted with the geodesic dome. Facility personnel also stated that the dome is water-tight. No signs of water intrusion were observed during inspection. The dome, associated support members, and sealant are in good condition with no signs of deterioration or damage.

6. INTERNAL FLOATING ROOF

Tank 255 is equipped with a lap-welded, steel internal floating roof (IFR). The IFR was inspected using

VT methods. The IFR is not provided with grounding cables to dissipate static buildup due to normal operations. One (1) grounding cable was observed attached to the geodesic dome roof support; however, the cable hangs freely and is not attached to the IFR. The IFR is provided a double wiper peripheral seal.

The seal is torn with significant portions of the seal missing. Product was observed in the gap between the IFR and tank shell.

7. TANK APPURTENANCES

a. TANK SHELL

Tank 255 is equipped with sixteen (16) shell nozzle penetrations: one (1) 32-inch by 20-inch manway, two (2) Type III return HLCV float pilot penetrations, one (1) 8-inch Type III return, one (1)

6-inch receipt, one (1) 8-inch fill stand issue/transfer, one (1) 12-inch Type III issue, one (1) 4-inch

LLA penetration, two (2) 1 ½-inch receipt HLCV float pilot penetrations, two (2) 1 ½-inch HLA penetrations, one (1) 4-inch stripper, one (1) 3-inch water draw-off, one (1) 3-inch PST return, and one (1) AFFF discharge chamber.

Reinforcement pads for the Type III return, Type III issue, receipt, fill stand issue/transfer, and LLA are provided with square corners. Square cornered attachments should be avoided as they are potential stress risers. No visual signs of stress cracking were observed at the time of inspection.

Reinforcement pads for the receipt and fill stand issue/transfer are welded approximately 2 ½-inches from the shell-to-bottom weld. The reinforcement pad for the Type III issue is welded approximately 2-inches from the shell-to-bottom weld. The receipt HLCV float pilot is welded approximately 1-inch from the horizontal weld between shell courses 6 and 7 and the Type III return

HLCV float pilot is welded at the horizontal weld between shell courses 6 and 7. API requires a minimum spacing of 3-inches to compensate for stresses in the heat affected zone. No visual signs of stress cracking were observed during the inspection. Due to the age and service history of the tank, attachment and nozzle spacings are considered adequate. The areas should continue to be monitored during future inspections. VT was limited on the Type III return HLCV float pilot due to the elevation of the appurtenance.

Skin valves for the Type III return, receipt, fill stand issue/transfer, water draw-off, PST return, and stripper nozzles are ball valves. UFC requires double block and bleed (DB&B) valves for tank skin valves. The receipt is also not provided a DB&B valve upstream of the HLCV. A DB&B valve is required upstream of the HLCV to provide positive isolation of the HLCV for maintenance activities. The manway is not equipped with means for cover plate movement and is not provided with confined space labeling.

Refer to Drawing A-1, “Shell Layout”, in Appendix A for shell nozzle locations and Table 2, “Nozzle/Repad UTT Measurement”, in Appendix A for nozzle and associated reinforcement pad UTT measurements.

b. GAUGING

The tank is provided an Enraf ATG with fully slotted stilling well and Vito temperature/water probe for automatic gauging. The Vito temperature/water probe is not provided a fully slotted stilling well.

A manual gauging hatch with fully slotted stilling well is provided for manual gauging and sampling operations and a Varec TLG is provided for monitoring product from the ground level. The TLG passed the field operability test. External coating on the TLG tubing exhibits flaking and base metal exposure with surface corrosion. Fasteners for the Enraf ATG exhibit surface corrosion.

c. LEVEL ALARMS

The tank is provided with independent, shell-mounted level alarms in the low and high positions as well as a HLCV float pilot for each of the receipt and Type III return lines for overfill protection.

According to facility personnel, the level alarms and the HLCV float pilot are functioning properly.

The tank is not provided a low-low level alarm (LLLA) or a high-high level alarm (HHLA). The LLA is not IAW UFC standards and AW standard design. The Type III return HLCV float pilot is currently inaccessible as it is not provided a means of access. The receipt HLCV float pilot, Type III return HLCV float pilot, and HLA assemblies are provided threaded nozzle connections. The PST is not provided with tubing to the HLA and HLCV float pilots to facilitate wet testing of the components.

d. STAIRS AND PLATFORMS

The tank is provided a spiral staircase with one (1) upper platform for access to the geodesic dome roof. The containment is provided one (1) concrete dike entry staircase. Coating on the dike entry handrails exhibits flaking and base metal exposure with surface corrosion.

e. GROUNDING AND BONDING

The tank shell is equipped with one (1) grounding lug; however, the lug does not have an associated grounding cable. Four (4) grounding cables should be provided for the tank in order to adequately dissipate static buildup due to normal operations.

8. TANK AND PIPING COATING

External coating for the tank shell, associated piping, and appurtenances is epoxy with a polyurethane topcoat. External coating on the tank shell, wind girder, chime, and spiral staircase exhibits corrosion staining, flaking, base metal exposure with surface corrosion, and widespread chalking. Coating on the containment carbon steel piping, Type III DB&B valve, and manway nozzle neck exhibits flaking, base metal exposure with surface corrosion, and widespread chalking.

A DFT survey was performed on the external tank shell. Refer to Table 3, “DFT Measurements”, in

Appendix A for tank shell DFT results.

9. TANK PIPING SYSTEM

The Type III return and issue piping are constructed of stainless steel. PST piping is constructed of both stainless steel and galvanized steel. All remaining piping is constructed of fully-coated carbon steel. PST piping is not provided with isolation at two (2) galvanized steel-to-stainless steel interfaces. This configuration accelerates corrosion at the galvanized steel piping. The PST piping is equipped with threaded connections. Threaded connections are no longer used as they are a potential leak path.

Thermal relief valves (TRV) and crossover piping for the Type III return, Type III issue, fill stand issue/transfer, and receipt are equipped with threaded connections and not provided test tees. The Type

III return, Type III issue, and fill stand issue/transfer TRVs are rated for vapor service. UFC requires that all TRV assemblies be in liquid service, provided test tees, and constructed of flanged or socket welded connections as threaded connections are a potential leak path.

The receipt is supported at the tank shell by an I-beam. The support is non-typical and not provided isolation. General corrosion was observed at the contact point between the piping and support. Pipe supports for the Type III return, fill stand issue/transfer, PST, receipt, and piping for other tanks in the tank farm (running through dike on the southeast side) are not provided with Teflon isolation pads and various supports are not fully engaged with the respective piping. Contact point corrosion was observed at various pipe-to-support interfaces. The PST piping is provided with hanger pipe supports, which is not recommended.

Fasteners for the Type III return connecting flanges and HLCV body exhibit surface corrosion. Flow arrows and product designation labeling for the Type III issue exhibits fading and peeling. Flow arrows also indicate that fluid can move both to and from the tank. According to facility personnel, the piping is only capable of issuing product from the tank. Fill stand issue/transfer, receipt, and Type III return piping are not provided flow arrows or product designation labeling.

10. FIRE PROTECTION SYSTEM

For internal fire protection, a steel IFR is provided. The tank is also provided an AFFF system and flapper valves with fusible links at the receipt and Type III return. These forms of fire protection are redundant.

According to facility personnel, there have been issues in the past with fusible link failures not associated with a fire.

11. SECONDARY CONTAINMENT

Tank 255 is located within a 100-foot long by 94-foot wide earthen containment dike covered with a flexible membrane liner (FML). The dike has sloped walls measuring 6-feet high with a slope length of

15-feet. The capacity of the secondary containment is approximately 15,294 BBL (642,339 gallons) and meets the 1-foot capacity requirement of UFC. The containment is provided a plastic grate walkway around the perimeter of the tank shell. According to facility personnel, the containment drain valve is in good condition.

One (1) soil access port adjacent to the tank spiral staircase is not sealed to the FML. The port is also capable of being removed, presenting a pathway for fluid to escape in the event of a spill.

C. FINDINGS AND RECOMMENDATIONS

Based on the in-service API 653 inspection of Tank 255 located at Wright-Patterson AFB in Dayton, Ohio, preliminary repair/upgrade recommendations have been identified. The following recommendations outline observations from this inspection. All repair recommendations are based on applicable sections of

API 650/653, UFC 3-460-01/3-460-03, DoD AW 78-24-27, NFPA 407, Occupational Safety and Health

Administration (OSHA) guidelines, BMPs and industry standards.

1. MANDATORY REPAIRS PER API 650/653, UFC 3-460-01/3-460-03, OR DoD AW 78-24-27

Mandatory repairs represent items that require immediate attention in order to prevent imminent risk to system operators, equipment integrity, or the adjacent environment. The tank should be removed from service until these repairs are completed.

No mandatory repairs are required for Tank 255.

2. SHORT-TERM RECOMMENDED REPAIRS

Short-term recommended repairs are repairs that will assist in maintaining tank operability and serviceability or are required to meet current codes. Short-term recommended repairs should be performed within five (5) years of the inspection date.

2.1 Shell Coating

OBSERVATION: Coating on the tank shell, exhibits corrosion staining, flaking, base metal exposure with surface corrosion, and widespread chalking.

REFERENCE: UFC 3-460-01, Section 8-3.10

RECOMMENDATION: Provide a full recoat of the tank shell, approximately 6,650 ft2.

2.2 Wind Girder Coating

OBSERVATION: Coating on the wind girder exhibits flaking, base metal exposure with general corrosion, and pitting.

RECOMMENDATION: Provide a full recoat of the wind girder, approximately 150 ft2.

2.3 Chime Coating

OBSERVATION: Coating on the chime, exhibits cracking, flaking, and spot base metal exposure with minor surface corrosion.

RECOMMENDATION: Provide a full recoat of the tank chime, approximately 150 ft2.

2.4 Spiral Staircase Coating

OBSERVATION: Coating on the spiral staircase exhibits corrosion staining, flaking, base metal exposure with surface corrosion, and widespread chalking.

RECOMMENDATION: Provide a full recoat of the tank spiral staircase, approximately 300 ft2.

2.5 Nozzles, Piping, and Appurtenances Coating

OBSERVATION: Coating on the Varec TLG tubing, 12-inch Type III issue DB&B valve, the 32-inch by 20-inch manway nozzle neck, 6-inch receipt piping, and 8-inch fill stand issue/transfer piping exhibits corrosion staining, flaking, base metal exposure with surface corrosion, and widespread chalking.

REFERENCE: UFC 3-460-01, Section 8-3.10

RECOMMENDATION: Provide a full recoat of the Varec TLG tubing, 12-inch Type III issue DB&B valve, the 32-inch by 20-inch manway nozzle neck, 6-inch receipt piping, and 8-inch fill stand issue / transfer piping, approximately 400 ft2.

2.6 Containment Piping Coating

OBSERVATION: Coating for adjacent tank piping running through the containment exhibits flaking, base metal exposure with surface corrosion, and widespread chalking.

REFERENCE: UFC 3-460-01, Section 9-10 (a)

RECOMMENDATION: Provide a full recoat of the carbon steel piping within the secondary containment, approximately 900 ft2.

2.7 Tank Nozzle TRVs

OBSERVATION: TRVs and crossover piping for the Type III return, Type III issue, fill stand issue / transfer issue, and receipt are equipped with threaded connections and not provided with test tees. The Type III return, Type III issue, and fill stand issue / transfer TRVs are rated for vapor service.

REFERENCE: UFC 3-460-01, Section 9-3.5.1

RECOMMENDATION: Provide the Type III return, Type III issue, fill stand issue / transfer, and receipt with standard TRVs and crossover piping IAW UFC and AW requirements. TRVs shall be rated for liquid service, equipped with test tees, and constructed with flanged or socket welded connections.

2.8 Tank Nozzle Skin Valves

OBSERVATION: Skin valves for the Type III return, receipt, fill stand issue / transfer, water draw-off, PST return, and stripper nozzles are ball valves. UFC requires that tank skin valves be DB&B valves to provide positive isolation of the tank during maintenance and inspection activities.

REFERENCE: UFC 3-460-01, Section 4-6 (i)

RECOMMENDATION: Provide the following nozzles with DB&B skin valves:

• 12-inch Type III Return

• 6-inch Receipt

• 8-inch Fill Stand Issue/Transfer

• 3-inch Water Draw-Off

• 3-inch PST Return

• 4-inch Stripper Nozzle

2.9 Receipt Pipe Support

OBSERVATION: The receipt is supported at the tank shell by an I-beam. The support is non-typical and not provided isolation. General corrosion was observed at the contact point between the piping and support.

REFERENCE: AW 78-24-27, Sheet CD.13

RECOMMENDATION: Provide the receipt with a typical sliding pipe support at the tank shell and provide a Teflon isolation pad or equivalent.

2.10 Pipe Supports

OBSERVATION: Pipe supports for the Type III return, fill stand issue / transfer, PST, receipt, and piping for other tanks in the tank farm (running through dike on the southeast side) are not provided with Teflon isolation pads and various supports are not fully engaged with the respective piping. Contact point corrosion was observed at various pipe-to-support interfaces.

REFERENCE: AW 78-24-27, Sheet CD.11, Detail PS-1

RECOMMENDATION: Provide Teflon isolation pads or equivalent at the following locations:

• Receipt – Three (3) adjustable saddle pipe supports

• Fill stand issue / transfer – Three (3) adjustable saddle pipe supports

• Type III return – One (1) adjustable saddle pipe support

• PST – Seven (7) hanger pipe supports

• Adjacent tanks’ piping running through Tank 255 containment dike – Forty-eight (48) U-bolt pipe supports

Adjust saddle pipe supports to engage with piping at the following locations:

• Receipt – One (1) adjustable pipe support

• Fill stand issue / transfer – Two (2) adjustable saddle pipe supports

• Type III return – One (1) adjustable saddle pipe support

See Recommendation 3.10

2.11 IFR Peripheral Seal

OBSERVATION: The steel IFR is provided with a double wiper peripheral seal, which is torn, damaged and missing significant pieces. Product was visible beneath the pan from the geodome roof hatch.

REFERENCE: API 650, Annex H.4.4.4 Item c

RECOMMENDATION: Provide a mechanical shoe seal for the steel IFR. Steel IFRs should be provided with a mechanical shoe seal, rather than a double wiper seal, to avoid damage to the seal due to movement and ability to effectively attach the seal to the steel IFR.

2.12 Dike Access Handrail Coating

OBSERVATION: Coating for the dike access handrail exhibits flaking and base metal exposure with surface corrosion.

RECOMMENDATION: Provide a full recoat of the dike access handrail, approximately 50 ft2.

2.13 Soil Access Port

OBSERVATION: One (1) soil access port adjacent to the tank spiral staircase is not sealed to the containment FML and is capable of being removed, presenting a pathway for fluid to escape in the event of a spill. This port construction is typical of three (3) ports.

REFERENCE: UFC 3-460-03, Section 8-10.5.1 Item B

RECOMMENDATION: Replace the three (3) soil access ports with a boot and band clamp.

3. LONG-TERM RECOMMENDED REPAIRS

Long-term repairs that relate to repair/upgrade of an asset to bring it up to the current standard from the standard at time of construction. Long-term repairs represent items that should be addressed in a timely manner in order to prevent future potential risks to system operators, equipment integrity, or the adjacent environment.

3.1 Manway 1 Cover Plate

OBSERVATION: Manway 1 is not provided a davit arm with grease fitting to facilitate handling of the cover plate.

REFERENCE: API 650, Section 5.8.3.5

RECOMMENDATION: Provide Manway 1 with a davit arm with grease fitting to facilitate handling of the cover plate during maintenance and inspection activities.

3.2 Receipt DB&B Valve

OBSERVATION: The receipt is not provided a DB&B valve upstream of the HLCV. A DB&B valve is required upstream of the HLCV to allow isolation of the HLCV for maintenance and inspection purposes.

REFERENCE: UFC 3-460-01, Section 6-5 Item d (3) and AW 78-24-27, Sheet D.12, Detail 3

RECOMMENDATION: Provide the receipt with a DB&B valve upstream of the HLCV. Ensure adequate thermal relief is provided.

3.3 Type III Return HLCV Float Pilot

OBSERVATION: The Type III return HLCV float pilot is currently inaccessible, and not provided any means of access. This makes personnel unable to test the chamber and provide maintenance as necessary. The float pilot is also not provided with valves at the nozzle penetrations.

REFERENCE: UFC 3-460-03, Section 8-9.6.1.1

RECOMMENDATION: Relocate the Type III HLCV float pilot to the spiral staircase to facilitate testing and maintenance activities. Provide the new nozzles penetrations with valves for the

HLCV float pilot. See Recommendation 3.4

3.4 PST

OBSERVATION: The PST is not provided tubing to the HLA, Type III return HLCV float pilot, and receipt HLCV float pilot to facilitate wet testing of the components.

REFERENCE: AW 78-24-27, Sheet D.13 Detail 5

RECOMMENDATION: Provide tubing and pump IAW AW to the PST to facilitate wet testing of the HLA, Type III return HLCV float pilot, and the receipt HLCV float pilot systems. See

Recommendations 3.3 and 3.5

3.5 Tank Level Alarms

OBSERVATION: Tank 255 is not provided with a LLLA or HHLA. The tank is provided with a HLA and LLA. The HLA and LLA are non-standard alarm systems. The LLA is provided a reinforcement pad with no tell tale hole.

REFERENCE: UFC 3-460-01, Table 8-1 Item l and AW 78-24-27, Sheet D.12

RECOMMENDATION: Provide the tank with standard level alarms in the high, high-high, low, and low-low level positions IAW UFC and AW standards. Remove the reinforcement pad for the LLA. See Recommendation 3.4

3.6 Receipt and Type III Return HLCV Tubing

OBSERVATION: Tubing provided for the receipt and Type III return HLCVs are not provided standard conduit supports on the tank shell. Three (3) of the receipt HLCV tubing supports are broken, one (1) of which has been repaired using zip ties. The tubing for both the receipt and Type III return are in contact with the tank shell at multiple locations due to the configuration. Contact point corrosion was observed during inspection.

REFERENCE: AW 78-24-27, Sheet D.10 Detail 5

RECOMMENDATION: Provide typical supports for the HLCV float pilot tubing and rework so the tubing is not in contact with the tank shell. Note that coating repair at contact points is included in Recommendation 6.

3.7 AFFF and Flapper Valves

OBSERVATION: The tank is provided an AFFF system and flapper valves with fusible links at the receipt and Type III return. These forms of fire protection are redundant, as the tank is provided with an IFR for fire protection. According to facility personnel, there have been issues in the past with fusible link failures not associated with a fire.

REFERENCE: UFC 3-460-01, Section 2-14.2.2

RECOMMENDATION: With approval from the base fire chief, remove the AFFF discharge chambers and associated piping as well as the flapper valves with fusible links.

3.8 Nozzle and Piping Threaded Connections

OBSERVATION: Nozzles for both the receipt and Type III return HLCV float pilots, HLA, and PST piping are provided threaded connections, Threaded connections should be avoided as they are a potential leak path.

REFERENCE: UFC 3-460-01, Section 9-8 (e)

RECOMMENDATION: Provide both HLCV float pilot nozzles, HLA nozzles, and PST piping with flanged or socket welded connections. See Recommendation 3.9

3.9 PST Piping

OBSERVATION: Piping for the PST consists of both stainless steel and galvanized steel, which are directly connected. Such configuration creates a galvanic corrosion cell, accelerating corrosion at the galvanized steel piping. Areas of surface corrosion were observed on the galvanized steel piping.

REFERENCE: BMP

RECOMMENDATION: Provide PST piping with one (1) isolation flange kit at the point where galvanized steel piping joins with stainless steel piping to mitigate galvanic corrosion and one

(1) dielectric union at the threaded galvanic steel-to-stainless steel joint. See

Recommendations 3.8 and 3.10

3.10 PST Pipe Supports

OBSERVATION: Piping for the PST is provided seven (7) hanger type pipe supports. Crevice corrosion was observed at the pipe-to-support interfaces.

REFERENCE: UFC 3-460-01, Section 9-3.2

RECOMMENDATION: Provide standard pipe supports for PST piping IAW UFC and AW standards. See

Recommendation 2.10

3.11 Type III Return Fasteners

OBSERVATION: Fasteners for the Type III return connecting flanges and Type III HLCV body exhibit surface corrosion.

REFERENCE: BMP

RECOMMENDATION: Replace twenty-four (24) fasteners for the Type III return connecting flanges and sixteen (16) for the Type III return HLCV body with stainless steel fasteners.

3.12 Tank Grounding

OBSERVATION: Tank 255 is not provided with grounding cables. One (1) grounding lug is provided, however there is no associated grounding cable attached to the lug.

REFERENCE: AW 78-24-27, Sheet ED.02, API 650 Section 5.8.11.3

RECOMMENDATION: Provide Tank 255 with four (4) grounding cables evenly spaced around the perimeter of the tank.

3.13 Tank Labeling

OBSERVATION: Tank product designation labeling exhibits fading and is no longer legible. The tank is also not provided with an NFPA emergency responder diamond.

REFERENCE: UFC 3-460-01, Section 2-17 Item c

RECOMMENDATION: Provide the tank with new product designation labeling and an NFPA emergency responder diamond.

3.14 Manway 1 and Geodome Hatch Confined Space Labeling

OBSERVATION: Manway 1 is not provided with proper confined space labeling, and the geodesic dome roof hatch confined space labeling exhibits fading.

REFERENCE: UFC 3-460-01, Section 2-17

RECOMMENDATION: Provide Manway 1 and the geodesic dome roof hatch with confined space labeling.

3.15 Vito Probe Stilling Well

OBSERVATION: The Vito temperature/water probe is not provided with a fully slotted stilling well.

REFERENCE: UFC 3-460-01, Table 8-1 Item w, DLA ATG Installation Policy

RECOMMENDATION: Fully slot the stilling well for the Vito temperature/water probe.

3.16 Enraf ATG Fasteners

OBSERVATION: Fasteners for the Enraf ATG exhibit surface corrosion.

REFERENCE: BMP

RECOMMENDATION: Replace twenty (20) carbon steel fasteners at the Enraf ATG with stainless steel fasteners or provide isolation flange washers.

3.17 IFR Grounding

OBSERVATION: The tank IFR is not provided with proper grounding. One (1) grounding cable was observed; however, it is currently hanging freely from its roof attachment point and not attached to the IFR.

REFERENCE: API 650, Annex H.4.1.6 and UFC 3-460-01, Section 8-8.3 Item c

RECOMMENDATION: Provide the IFR with two (2) grounding cables, 180 degrees apart, to adequately dissipate static buildup due to normal operations.

3.18 IFR Anti-Rotation

OBSERVATION: The tank IFR is not provided with anti-rotation devices.

REFERENCE: API 650, Annex H.5.4 and UFC 3-460-01, Section 8-8.3 Item d

RECOMMENDATION: Provide the IFR with anti-rotation devices to resist rotation and maintain the IFR centered position.

3.19 Piping Flow Arrows and Product Designation Labeling

OBSERVATION: Flow arrows and product designation labeling for the Type III issue exhibits fading and peeling. Flow arrows also indicate that the piping is bidirectional. According to facility personnel, the piping is only capable of issuing product from the tank.

The fill stand issue / transfer, receipt, and Type III return piping are not provided with flow arrows or product designation labeling.

REFERENCE: UFC 3-460-01, Section 2-17

RECOMMENDATION: Provide flow arrows and product designation labeling for the type II issue, Type III return, fill stand issue / transfer, and receipt.

APPENDIX A: ENGINEERING CALCULATIONS AND DRAWINGS

6'-0"

6'-0"

6'-0"

6'-0"

6'-0"

6'-0"

6'-0"

TANK FOUNDATION

WIND

GIRDER

MW1

N3

N1

N2

N4

N5

N6

N7

N8

N9

N10

N11

N12 N13

N14

N15

FLAPPER VALVE

CONDUIT SUPPORT

(TYP. 8)

LEVEL ALARM

CONDUIT SUPPORT

(TYP. 2)

HLCV TUBING

CONDUIT SUPPORT

(TYP. 17)

VAREC TLG

CONDUIT SUPPORT

(TYP. 4)

AFFF PIPE SUPPROT

(TYP. 4)

UPPER PLATFORM

SUPPORT

GROUNDING

LUG

THICKENED INSERT PLATE

0.493"

GEODESIC DOME ROOF

1-1 1-2

1-3 1-4 1-5

2-1 2-2 2-3 2-4 2-52-6

3-1 3-2 3-3 3-4 3-5 3-6

4-6 4-1 4-2 4-3 4-4 4-5

5-6 5-1 5-2 5-3 5-4 5-5

6-6 6-1 6-2 6-3 6-4

7-5 7-6 7-1 7-2 7-3 7-4

NAMEPLATE (TYP. 3)

6-5

NOTES:

1. REFER TO TABLE 1, "SHELL UTT MEASUREMENTS", IN

APPENDIX A FOR INDIVIDUAL SHELL PLATE UTT

READINGS.

2. REFER TO TABLE 2, "NOZZLE / REPAD UTT

MEASUREMENTS", IN APPENDIX A FOR NOZZLE DATA.

C O

N T

R A

C T

N

O

F I L E

A M

E

D W

N

B

Y

C K

D

B

Y

D E

S I G

N E

D

B

Y

D E

S C

R I P

T I O

N

D

2 3

C

A

B

M A

R K

A P

P R

D A

T E

F I

U M

B E

R

S I Z

E

S U

B M

I T

T E

D

B

Y

P L O

T

S

C A

L E

P

L O

T

D

A T

E

D A

T E

M A

R K

D E

S C

R I P

T I O

N

D E

L I V

E R

Y

O

R D

R

SHEET

IDENTIFICATION

D A

T E

A P

P R

SHEET OF

U S

A

R M

Y

C

O R

P S

F

E

N G

I N

E E

R S

O M

A H

A

N

E

O M

A H

A

D

I S

T R

I C

T

D A

Y T

O N

O

H I O

W R

I G

H T

P

A T

T E

R S

F B

T A

K

Y O

U T

N T

S

N A

W

F

D

W

F

F

A N

S I

B

P a r k w a y

L a n e

S u i t e

P e a c h t r e e

C o r n e r s

G

A

P h o n e

F a x

J O

B

N

O

A E

C

C J P

A D

M

N A

TANK INFORMATION

TANK NO.: TANK 255

MANUFACTURER: CHICAGO BRIDGE & IRON CO.

YEAR BUILT: 1952

TANK DIAMETER: 42'-6"

TANK HEIGHT: 42'-0"

NOMINAL CAPACITY: 10,000 BBLS

PRODUCT: JET-A

PRODUCT SPECIFIC GRAVITY: 0.84

GPS COORDINATES: 39.830968°, -84.027954°

N A

S H

E L

L

L A

Y O

U T

A-1

NOZZLE

SCHEDULE

NOZZLE

SIZE

SHELL LAYOUT

MW1 32" x 20" MANWAY

N1 - TYPE III RETURN HLCV FLOAT PILOT

N2 - TYPE III RETURN HLCV FLOAT PILOT

N3 8" TYPE III RETURN

N4 6" RECEIPT

N5 8" FILL STAND ISSUE/TRANSFER

N6 12" TYPE III ISSUE

N7 4" LLA

N8 1

" RECEIPT HLCV FLOAT PILOT

N9 1

" RECEIPT HLCV FLOAT PILOT

N10 1

" HLA

N11 1

" HLA

N12 4" STRIPPER

N13 3" WATER DRAW-OFF

N14 3" PST RETURN

N15 - AFFF

LEGEND:

- UTT READING0.XXX"

TABLE 1 - SHELL UTT MEASUREMENTS

Roof

Shell Course

Plate 7-1 Plate 7-2 Plate 7-3 Plate 7-4 Plate 7-5 Plate 7-6 .177 .179 .178 .177 .178 .180 .178 .178 .179 .176

Avg. .178 Circumferential Weld C7

Shell Course

Plate 6-1 Plate 6-2 Plate 6-3 Plate 6-4 Plate 6-5 Plate 6-6 .175 .175 .173 .176 .175 .177 .176 .177 .177 .180

Avg. .176 Circumferential Weld C6

Shell Course

Plate 5-1 Plate 5-2 Plate 5-3 Plate 5-4 Plate 5-5 Plate 5-6 .180 .184 .181 .184 .183 .183 .184 .183 .183 .184

Avg. .183 Circumferential Weld C5

Shell Course

Plate 4-1 Plate 4-2 Plate 4-3 Plate 4-4 Plate 4-5 Plate 4-6 .188 .189 .187 .188 .187 .186 .186 .188 .187 .186

Avg. .187 Circumferential Weld C4

Shell Course

Plate 3-1 Plate 3-2 Plate 3-3 Plate 3-4 Plate 3-5 Plate 3-6 .183 .182 .183 .185 .183 .183 .183 .180 .182 .184

Avg. .183 Circumferential Weld C3

Shell Course

Plate 2-1 Plate 2-2 Plate 2-3 Plate 2-4 Plate 2-5 Plate 2-6 .246 .240 .240 .244 .243 .239 .241 .240 .236 .235

Avg. .240

TABLE 1 - SHELL UTT MEASUREMENTS (CONTINUED)

Circumferential Weld C2

Shell Course

Plate 1-1 Plate 1-2 Plate 1-3 Plate 1-4 Plate 1-5 .249 .252 .247 .246 .250 .247 .242 .243 .247 .248 .252 .248 .246 .254 .253 .250 .255 .248 .247 .253 .251 .245 .247 .248 .253 .254 .252 .249 .255 .254 .250 .254 .250 .248 .250 .244 .243 .244 .248 .251 .254 .251 .247 .255 .251

Avg. .251 .248 .245 .251 .252 Circumferential Weld C1

Thickness represented in inches. Average shell course 2: .240” Average shell course 4: .187” Average shell course 6: .176”

Average shell course 1: .249” Average shell course 3: .183” Average shell course 5: .183” Average shell course 7: .178”

TABLE 2 - NOZZLE / REPAD UTT MEASUREMENTS

Nozzle Nozzle Size

(Diameter or Width/Height)

Repad Shape

Repad Size (W X H)

Repad Thickness

Nozzle Thickness H1 H2

Nozzle Location (Measured circumferentially from Manway 1)

Notes

0⁰ 90⁰ 180⁰ 270⁰

MW1 32” x 20” A 46” x 66” .389 .343 .329 .345 .343 2’-6” 0’-7 ½” 0’-0” Manway

N1 - - - - - - - - - - 4’-5” Type III Return HLCV Float Pilot

N2 - - - - - - - - - - 4’-5” Type III Return HLCV Float Pilot

N3 8” A 24” x 21” .350 .324 .319 .314 .317 1’-0” 0’-4” 4’-5” Type III Return

N4 6” A 20” x 16” .253 .424 .415 .415 .440 0’-10 ½” 0’-2 ½” 36’-10” Receipt

N5 8” A 24” x 20” .265 .491 .507 .485 Obstr. 1’- ½” 0’-2 ½” 69’-10” Fill Stand Issue/Transfer

N6 12” A 36” x 31” .366 .383 .376 .389 .396 1’-2 ½” 0’-2” 102’-9” Type III Issue

N7 4” A 8” x 10” Obstr. Obstr. Obstr. Obstr. Obstr. 1’-6” 1’-1” 105’-8” LLA

N8 1 ½” - - TH TH TH TH TH 37’-9 ½” 37’-8” 108’-3” Receipt HLCV Float Pilot

N9 1 ½” - - TH TH TH TH TH 35’-9 ½” 35’-8” 108’-3” Receipt HLCV Float Pilot

N10 1 ½” - - TH TH TH TH TH 37’-3 ½” 37’-2” 110’-4” HLA

N11 1 ½” - - TH TH TH TH TH 36’-4” 36’-3” 110’-4” HLA

N12 4” D 12” x 15” .373 .332 .335 .336 .332 0’-9” - 122’-0 Stripper

N13 3” D 18” x 27” (TIP) .492 .243 .291 .287 .290 1’-6” - 127’-11” Water Draw-Off

N14 3” D 18” x 27” (TIP) .492 .291 .303 .280 .280 0’-10” - 127’-11” PST Return

N15 - - - - - - - - - - 129’-7” AFFF

Thickness measurements are in inches.

H1 = Centerline of pipe to edge of tank chime

H2 = Edge of tank or chime to toe weld of reinforcement pad or nozzle

TH = Threaded

TIP = Thickened insert plate

Obstr. = Obstruction. UTT readings could not be obtained on the LLA due to the flange distance from the shell and on the fill stand issue/transfer due to surface irregularities.

Repad shapes:

TABLE 3 – DFT MEASUREMENTS

External Shell Coating Thickness Average Standard Deviation Number of Readings Minimum Maximum

13.73 5.19 20 7.04 24.44 Thicknesses are represented in mils.

TABLE 4 – SHELL SETTLEMENT MEASUREMENTS

Point Arc Length

(ft.)

Tank Chime

(ft.)

1 0.00 0.54 2 16.69 0.49 3 33.38 0.54 4 50.07 0.50 5 66.76 0.50 6 83.45 0.51 7 100.14 0.52 8 116.83 0.52

Settlement points were measured clockwise from MW1.

The listed data should be used in future API inspections for comparison.

API-653 APPENDIX B SHELL SETTLEMENT EVALUATION

(para. B.2.2.4)

Report No Client Inspector Vessel Date WPAFB Tank 255 USACE ADM Tank 255 10/08/2020

Base Elev Max Elev Elev

FT 0.490 0.540 0.050 R^2 = 0.698

IN 5.880 6.480 0.600

MorrissetteA Text Box The optimum cosine curve used in the shell settlement evaluation per API 653 para. B.2.2.4 is invalid as R2 is less than 0.90. As an alternative, the evaluation provided in API 653 para. B.2.2.5 was used in determining shell settlement. See next page.

(para. B.2.2.5)

Report No. Client Inspector Vessel Date

WPAFB Tank 255 USACE ADM Tank 255 10/08/2020

Base Elev Max Elev Elev

FT 0.490 0.540 0.050

IN 5.880 6.480 0.600

Report No.: WPAFB Tank 255

D H Roof Type 1st Crs Plt Spec Y E K

42.500 42 F A 36 36000 29000000 10.500

Where:

D = Tank Diameter, in ft H = Tank Height, in ft Roof Type: F = fixed, O = Open Y = Yield strength of shell 1st course , in pounds per Sq.Inch (psi) E - Young's modulus, in pounds per Sq.Inch (psi) K = factor from table in B.3.2.2 (API-653 App. B) PE2 = Predicted elevation (for secondary evaluation), in ft Sarc = the effective settlement arc length, see B.2.2.5.1, in ft Si = out-of-plane settlement, in inch Smax = Maximum allowed out-of-plane settlement, in inch (min(K*Sarc*(D/H)*(Y/E), 4.0)

Point Elevation PE2 Sarc Si Smax Results

1 0.540 0 0.540 33.4 0.000 0.440 SAT

2 0.490 45 0.540 33.4 0.600 0.440 UNSAT

3 0.540 90 0.540 100.1 0.000 1.320 SAT

4 0.500 135 0.540 100.1 0.480 1.320 SAT

5 0.500 180 0.540 100.1 0.480 1.320 SAT

6 0.510 225 0.540 100.1 0.360 1.320 SAT

7 0.520 270 0.540 100.1 0.240 1.320 SAT

8 0.520 315 0.540 100.1 0.240 1.320 SAT

MorrissetteA

The maximum measured out-of-plane deflection is 0.600 inches and maximum allowable deflection is 0.440 inches; therefore, the tank is not within API 653 acceptable limits. The allowable deflection of the tank is not accurately represented by the above analysis due to the small size of the tank which results in a small arc length. No visual settlement was identified during the inspection. It is recommended to monitor the tank settlement during future inspections.

SHELL MINIMUM THICKNESS CALCULATIONS

Tank Shell Minimum Thickness and Remaining Life Calculations Date 10/08/2020

File No. Report No. Client Tank No. Temp. (degF) Initials

4462 WPAFB Tank 255 USACE Tank 255 ADM tmin = 2.6(H-1)DG

SE

Where:

H = The height above the bottom of the course of study to the maximum liquid level height of the product, in ft. For corroded or pitted areas, H = the height from the bottom of the corroded or pitted area to the maximum liquid level height of the product, in ft.

tmin = The calculated minimum acceptable shell thickness, in inch (cannot be less than

0.10 inch for any course). The minimum acceptable shell thickness allowed by API-653 and STI-SP001 for tank size, in inch .

D = Nominal diameter of tank, in ft.

G = Highest specific gravity of the contents (including test water if tank will, or may, be tested in the future).

S = Maximum allowable stress, in psi. For welded tanks; use the smaller of 0.80Y of 0.429T for bottom and second course or the smaller of 0.88Y or 0.472T for all other courses. For riveted tanks; S = 21000 psi. For STI Tank Inspections S = 26000 psi (E = 1)

Y = Specified minimum yield strength of the plate, in psi; use 30000 psi if not known (N/A for riveted tanks).

T = The smaller of the specified minimum tensile strength of the plate or 80000 psi; use 55000 psi if not known (N/A for riveted tanks).

E = Original joint efficiency for the tank. For welded tanks; use API-653, Table 2-1 ; use E =

1.0 when evaluating the retirement thickness in a corroded plate, when away from welds or joints by at least the greater of one inch or twice the plate thickness. For riveted tanks; use E = 1.0 for shell plates greater than 1 inch away from rivets; use the value of E from API- 653 Table 2-1 when within 1 inch of rivets. For STI Tank Inspections E = 1 where S = 26000 psi.

D (ft) 42.50 G 0.84 E 0.85 Fill Height (ft) 37.8

Material Crs H (ft) H (ft) S (psi) tmin (inch) Course 1 A 36 6 37.8 24900 0.161 Course 2 A 36 6 31.8 24900 0.135 Course 3 A 36 6 25.8 27400 0.100 Course 4 A 36 6 19.8 27400 0.100 Course 5 A 36 6 13.8 27400 0.100 Course 6 A 36 6 7.8 27400 0.100 Course 7 A 36 6 1.8 27400 0.100

SHELL REMAINING LIFE CALCULATIONS

Tank Shell Minimum Thickness and Remaining Life Calculations Date 10/08/2020

File No. Report No. Client Tank No. Temp. (degF) Initials

4462 WPAFB Tank 255 USACE Tank 255 ADM

Ca = tact-tmin = Remaining Corrosion Allowance (inch) Cr = tprev-tact / Y = Corrosion Rate (inch/Yr) RL = Ca / Cr = Remaining Life (year)

Y = 68 = Tank age (year)

Where:

Ca = Remaining corrosion allowance of the shell course under consideration, in inch.

Cr = Corrosion rate of the shell course under consideration, in inch per year.

FHc = Calculated fill Height = (SEtact/2.6DG+1) + (product height below course of interest), in ft.

tact = Minimum thickness measurement of the shell course under consideration, as recorded at the time of inspection, in inch.

tmin = minimum required thickness of shell course, at the maximum allowable fill height, in inch.

tprev = previous thickness measurement of shell course under consideration, as recorded at last inspection or nominal thickness if no previous thickness measurements, in inch.

RL = Estimated remaining life of the shell course under consideration, in year.

Y = Time span between thickness readings or age of the tank if nominal thickness is used for tprev, in year.

tprev tact tmin Ca Cr RL FHc Course 1 0.250 0.249 0.161 0.088 0.0000 5958 57.78 Course 2 0.250 0.240 0.135 0.105 0.0002 713 61.73 Course 3 0.188 0.183 0.100 0.083 0.0001 1129 58.92 Course 4 0.188 0.187 0.100 0.087 0.0000 5916 65.92 Course 5 0.188 0.183 0.100 0.083 0.0001 1129 70.92 Course 6 0.188 0.176 0.100 0.076 0.0002 431 75.16 Course 7 0.188 0.178 0.100 0.078 0.0002 530 81.66

MorrissetteA

Tprev is based on an assumed nominal thickness. The previous in-service inspection report dated July 2015 did not include thickness data.

NEXT INSPECTION

The interval between tank inspections (both internal and external) should be determined by the tank service history.

Inspection intervals can be adjusted based on known corrosion rates. Corrosion rates can only be determined when a comparison is made between UTT measurements taken over an interval of time. In this case, corrosion rates were determined using an assumed nominal thickness and UTT measurements taken during this inspection. Listed below are recommended inspection intervals:

1. Routine In-service Inspection

Facility personnel shall perform a visual inspection of the tank exterior surfaces and associated piping. Gross defects, leaks, shell distortions, signs of settlement, and corrosion should all be monitored along with the foundation condition (including tank chime-to-foundation joint), coating, and appurtenances.

a. Interval: Monthly

2. External Visual Inspection

Formal visual external inspection shall be performed by an API certified inspector every five (5) years or RCA/4N years (where RCA is the difference between the measured shell thickness and the minimum required thickness and

N is the shell corrosion rate), whichever is less. Based on the review of shell thickness measurements, the 5-year interval will govern the next external visual inspection. This inspection includes inspection requirements listed in a routine in-service inspection as well as a visual inspection of the tank grounding system.

b. Interval: Five (5) years; October 2025

3. External Visual Inspection with Ultrasonic Thickness Testing

An API certified inspector with the assistance of an NDT examiner shall perform this inspection. UTT measurements shall be taken to verify thickness of the tank shell and associated components. Obtained UTT measurements are used to determine corrosion rates and remaining life of the tank shell. UTT measurements of shell plates can be performed with the tank in service and scheduled at a maximum interval of fifteen (15) years or RCA/2N, whichever is less.

Based on shell thickness measurements and corrosion rates, the recommended interval for this inspection is fifteen

(15) years.

c. Interval: Fifteen (15) years; October 2035

4. Internal Inspection

An API certified inspector with the assistance of an NDT examiner shall perform this inspection. This inspection consists of verifying that the tank bottom is not severely corroded and/or leaking, identifying and evaluation tank bottom settlement, and inspection requirements listed in both external visual inspections. The next OOS API 653 inspection is based on recommendations from the previous in-service inspection report dated July 2015.

d. Interval: Twenty (20) years; August 2029

API/OSHA ACCESS STRUCTURE REPORT

API/OSHA Stairway…