Attachment J.5 Fac 3474 - Insp Report - Jan 2018.pdf

API 653 Out-of-Service Inspection Report Andrews AFB, Maryland

US Army Corps of Engineers Omaha District

API 653 Out-of-Service Inspection Report

Andrews AFB Facility 3474

Tank 2 US Army Corps of Engineers Center of Expertise for Petroleum, Oils and Lubricants

(USACE POL-MCX)

2/5/2018

Table of Contents

ACRONYMS AND ABBREVIATIONS

GENERAL SUMMARY

INSPECTION DATE

PREVIOUS INSPECTION DATES

RECOMMENDED FUTURE INSPECTION DATES

GENERAL TANK INFORMATION

A. GENERAL PROJECT INFORMATION

1. API 653 Inspection

2. Site Information

B. TANK INSPECTION COMMENTS

1. Tank Construction

2. Tank Foundation

3. Cathodic Protection

4. Tank Bottom

5. Tank Shell

6. Fixed Roof

7. Tank Appurtenances

a. Tank Shell

b. Fixed Roof

c. Gauging

d. Level Alarms

e. Stairs and Platforms

f. Grounding and Bonding

8. Tank Coating

9. Fire Protection System

10. Secondary Containment

11. Internal Floating Roof

C. OBSERVATIONS AND RECOMMENDATIONS

1. MANDATORY REPAIRS per API 653, UFC 3-460-01, or AW 78-24-27 Standards

2. RECOMMENDED REPAIRS to Fully Comply with API 653, UFC 3-460-01, or AW 78-24-27 Standards

3. RECOMMENDED REPAIRS as Part of Regular Maintenance

D. INSPECTION INTERVALS

1. Routine In-service Inspection

2. External (In-Service) Inspection

3. Ultrasonic Thickness Inspection

4. Internal (Out-of-Service) Inspection

APPENDIX A: ENGINEERING CALCULATIONS AND DRAWINGS

Drawing 01 Bottom Layout

Table 1: Tank Bottom Ultrasonic Thickness Readings

Table 2: Tank Bottom Critical Zone Ultrasonic Thickness Readings

Tank Bottom Service Life Evaluation

API 653 Appendix B Settlement Evaluation

Table 3: Tank Bottom Elevation Measurements

Drawing 02: Shell Layout

Table 4: Shell Plate Ultrasonic Thickness Readings

Shell Service Life Evaluation

Out-of-Roundness Evaluation

Drawing 03: Fixed Roof Layout

Table 5: Fixed Roof Ultrasonic Thickness Readings

Roof Life Evaluation

Table 6: Nozzle and Appurtenances

Table 7: Dry Film (Coating) Thickness

APPENDIX B: API 653 CHECKLISTS FOR TANK INSPECTIONS

APPENDIX C: PHOTOGRAPHS

ACRONYMS AND ABBREVIATIONS

AFB Air Force Base

API American Petroleum Institute

ATG Automatic Tank Gauge

BBL Barrel

BMP Best Management Practice

COMAR Code of Maryland Regulations

DB&B Double Block and Bleed

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

MFL Magnetic Flux Leakage

NDT Non-Destructive Testing

NFPA National Fire Protection Association

OOS Out-of-Service

SG Specific Gravity

UFC Unified Facilities Criteria

USACE United States Army Core of Engineers

UTT Ultrasonic Thickness Testing

VT Visual Testing

W/ With

W/O Without

GENERAL SUMMARY

POND was under contract to the United States Army of Engineers (USACE), Omaha District, to provide an out-of-service (OOS) American Petroleum Institute (API) 653 tank inspection, provide a hydrostatic test of the tank containment, and replace the internal floating roof primary and secondary seals with double wiper seals on Tank 2

(Facility 3474), at Andrews Air Force Base (AFB) located in Joint Base Andrews, Maryland.

The OOS API 653 inspection was performed 30-31 January, 2018 in accordance with (IAW) API 653, 5th Edition.

Results of this inspection and testing activities identified recommended repairs and upgrades required to comply with API 650/653, Unified Facilities Criteria (UFC) 3-260-01/3-460-03, AW 78-24-27, Code of Maryland

Regulations (COMAR), and industry standards.

Contained in this report is 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 of this report. Recommended repairs and upgrades identified in Section B are further classified and listed in Section C of this report.

INSPECTION DATE

API Out-of-Service Inspection Date: 30-31 January, 2018 Equipment Used:

Manufacturer: MFE Enterprises Tank Floor Scanner Model Number: MFE 2412 Mark III Calibration Method: Function Plate with Known Defect

Manufacturer: GE Krautkramer Ultrasonic Thickness Gauge with Topcoat Model Number: DMS GO+ Calibration Method: 1-point Calibration

Manufacturer: Fisher Technologies Dry Film Thickness Gauge Model Number: Dual Scope MPOR Calibration Method: Calibration to Known Thickness Standard

Manufacturer: Johnson Self-Leveling Rotary Laser Level Model Number: 40-6515 Calibration Method: Self-Leveling

Inspector(s):

John Cronin Andrew Morrissette

PREVIOUS INSPECTION DATES

API Out-of-Service (Internal) Inspection Date: Unknown API In-Service (External) Inspection Date: Unknown

RECOMMENDED FUTURE INSPECTION DATES

Routine In-Service: Monthly API 653 Out-of-Service (Internal): 31 January 2028 API In-Service (External) w/o UTT: 31 January 2023 w/ UTT: 31 January 2033

NOTE:

IAW UFC 3-460-03, New Summary Sheet, Unification Issues, the Air Force requires tanks above 20,000 gallons in capacity to be cleaned on a ten (10) year cycle. Coating along the shell-to-bottom weld is in poor condition displaying disbondment from the shell and allowing water ingress due to tank sweating. Integrity of this weld could not be inspected due to the presence and condition of the coating. Based on the significance of the integrity of this weld, it is recommended to maintain a ten (10) year inspection interval to further evaluate the coating and weld integrity.

John Cronin, EIT Andrew Morrissette Brian W. Lunsford, P.E.

Integrity Engineer Integrity Engineer Program Manager / Integrity Engineer

API 653 Inspector # 77554 API 653 Inspector #28526

GENERAL TANK INFORMATION

ITEM DESCRIPTION

Owner U.S. Air Force

Location Andrews AFB

Facility Number 3474

Tank Number 2

State / Country Maryland / United States

City Joint Base Andrews

Inspection Date 30-31 January, 2018

Tank Manufacturer Witherup Fabrication and Erection, Inc.

Design Standard API 650, 10th Edition, Revision B

Date of Construction 2005

Tank Contents JET-A (F-24) (SG = 0.85)

Tank Diameter 31’-0”

Tank Height 41’-3”

Design Liquid Level 37’-7”

Tank Capacity 5,000 Barrels (BBL) – 210,000 Gallons

Foundation Concrete Ring Wall

Construction

Bottom Cone Down / Lap-Welded Steel Plates

Shell Butt-Welded Steel Plates / Five (5) Shell Courses

Floating Roof Aluminum Honeycomb Pan / Double Wiper Seal System

Fixed Roof Lap-Welded Steel Plates / Cone-Up / Self-Supported

Material

Bottom Carbon Steel

Shell A-36 MOD Carbon Steel

Floating Roof Aluminum

Fixed Roof Carbon Steel

Cathodic Protection Impressed Current Cathodic Protection (ICCP) System

Interior Coating System Unknown (Assumed Epoxy Based)

Exterior Coating System Unknown (Assumed Epoxy Based)

Level Gauging Enraf Automatic Tank Gauge (ATG)

Overfill Protection High Level Control Valve (HLCV) and HLCV Shut-Off Switch / Four (4) Overflow Vents

Piping Product Receipt 8” Carbon Steel

Main Suction 12” Carbon Steel

Water Draw-Off 1 ½” Carbon Steel

Low Suction 4” Carbon Steel

Level Alarms High Level Alarm (HLA), High-High Level Alarm (HHLA), Low Level Alarm (LLA), and Low-Low Level Alarm (LLLA)

A. GENERAL PROJECT INFORMATION

1. API 653 Inspection

An OOS API 653 inspection was performed 30-31 January, 2018 on Tank 2 (Facility 3474). Results of this inspection identified recommended repairs and upgrades required to comply with API 650/653, UFC 3-460-01/3-460-03, AW 78-24-27, and industry standards.

2. Site Information

Andrews Air Force Base is the airfield portion of Joint Base Andrews which is under the jurisdiction of the United States Air Force. In 2009, Andrews Air Force Base merged with Naval Air Facility

Washington to form Joint Base Andrews. Andrews is the home base of two Boeing VC-25A aircraft with the call sign Air Force One when the president is on board, that serve the President of the United States.

The host unit at Andrews is the 11th Wing, assigned to the Air Force District of Washington. It is responsible for maintaining emergency reaction rotary-wing airlift and other National Capital Region contingency response capabilities critical to national security; and for organizing, training, equipping and deploying combat-ready forces for Air and Space Expeditionary Forces.

B. TANK INSPECTION COMMENTS

1. Tank Construction

Tank 2 (Facility 3474) is a welded, steel, single-wall, JET-A (F-24), vertical aboveground storage tank.

The tank was constructed in 2005 by Witherup Fabrication and Erection, Inc. IAW API 650 10th Edition, Revision B. Tank 2 is 31’-0” in diameter and 41’-3” high with a nominal capacity of 5,000 BBL.

Construction drawings were not available for review. The facility possesses strapping charts for the tank. Strapping charts are provided in 1” increments with a separate column for calculating values within 1/16” increments.

2. Tank Foundation

Tank 2 rests on a concrete ring wall foundation. The tank chime-to-ring wall interface is provided with sealant in good overall condition displaying only minor signs cracking and staining. Sealant provided at the tank ring wall-to-containment interface is in poor condition and exhibits signs of voids, cracking, disbondment, and vegetation growth. A settlement evaluation was performed during the inspection. No signs of settlement were noted. See Appendix A for settlements results.

3. Cathodic Protection

The tank is cathodically protected from soil-side corrosion by an ICCP system.

4. Tank Bottom

The tank bottom is of cone-down construction with lap-welded carbon steel plates. The tank bottom was examined using magnetic flux leakage (MFL), ultrasonic thickness testing (UTT), and visual testing

(VT) methods. The MFL bottom scan revealed no indications of top-side or soil-side indications. Five

(5) UTT measurements were taken on each bottom plate. One (1) UTT reading was taken every 2 feet around the tank perimeter within the tank bottom critical zone.

UTT readings revealed no significant metal loss on bottom plates. VT was performed along the bottom plate lap-welds and the bottom-to-shell weld. Coating along the shell-to-bottom weld displays disbondment. Due to possible sweating of the tank during change in temperatures throughout the day, moisture may seep behind the coating and come in contact with the shell-to-bottom weld. VT examination of the shell-to-bottom weld was limited due to the presence and condition of the internal coating. Two (2) anti-rotation cables are attached to the bottom via square-cornered attachments.

Square corners present stress risers that could affect the integrity of the weld. The tank is currently equipped with a 29” diameter, 9” deep center sump. Coating provided for the center sump displays minor signs of failure and deterioration. Widespread pitting was observed throughout the tank bottom.

Maximum pit depth was found to be 0.035”. This value is within the maximum tolerance allowed by

API. At the time of the inspection, pitting was coated and inactive. Pitting may have been limited to impurities and inclusions in the coating, caused by improper application or incorrect surface preparation.

Refer to Drawing 01, “Bottom Layout” for the bottom plate layout and Table 1, “Tank Bottom Ultrasonic

Thickness Readings” and Table 2, “Tank Bottom Critical Zone Ultrasonic Thickness Readings” in

Appendix A for bottom plate UTT readings.

5. Tank Shell

The tank shell is equipped with five (5) butt-welded A-36 MOD steel shell courses. Shell plates were examined using UTT and VT methods. Nine (9) UTT measurements were taken on each plate of the 1st shell course. Nine (9) UTT measurements were taken on the 2nd through 5th shell course using the spiral staircase for access. UTT readings indicated no significant metal loss. The tank shell is not provided with a National Fire Protection Association (NFPA) emergency responder diamond. Conduit provided for the HLCV shutoff and visible alarm system is supported along the tank shell via-stitch welded connections. Stitch-welding creates a crevice between the shell and support. Crevice corrosion and weep staining was observed during the inspection at the interstice.

Refer to Drawing 02, “Shell Rollout” and Table 4, “Shell Plate Ultrasonic Thickness Readings” in

Appendix A for the shell plate layout and UTT readings.

6. Fixed Roof

The self-supported fixed roof is of cone-up construction with fully coated lap-welded steel plates. Fixed roof plates were examined using UTT and VT methods. Five (5) UTT measurements were taken on each fixed roof plate. UTT readings indicated no significant metal loss on the fixed roof plates.

Refer to Drawing 03, “Fixed Roof Layout” and Table 5, “Fixed Roof Ultrasonic Thickness Readings” in

Appendix A for plate location and UTT readings.

7. Tank Appurtenances

a. Tank Shell

Shell nozzles consist of three (3) 36” manways, one (1) 8” receipt, two (2) 1 ½” HLCV shut-off switch penetrations, two (2) 1 ½” high level alarm penetrations, two (2) low level alarm (2) penetrations, one (1) 12” main suction, one (1) 4” low suction, and one (1) 1 ½” water draw-off line. Shell nozzles and reinforcement pads were examined using UTT and VT methods. Four (4)

UTT reading were taken on each nozzle with a welded connection in each of four (4) quadrants

(0°, 90°, 180°, and 270°). One (1) UTT reading was taken on each reinforcement pad. UTT readings indicated no significant metal loss. Tell-tale holes provided for reinforcement pads are open to the atmosphere. The main suction and receipt piping is not provided standard military labeling. Crossover piping provided for the receipt and main suction lines are provided with sight flow indicators. Sight flows are no longer used in this application as they present potential leak paths. Coating provided for the main suction and receipt crossover piping, HLA, HHLA, HLCV shutoff, and the LLA displays flaking, corrosion staining, and deterioration. The HLA, HHLA, HLCV, and LLA are provided with threaded connections. The low suction line is provided with a 4” threaded connection proceeding the cam lock connection. UFC limits the use of threaded connections as they may not provide an adequate seal. The water draw-off line is provided with a ball valve at the tank skin location. Double block and bleed (DB&B) valves should always be used at the skin location as a ball valve may not provide adequate isolation during maintenance and inspection activities.

The internal main suction line extends half the tank radius; however, does not turn down towards the tank bottom. Neither the main suction nor low suction piping is provided with U-bolt attachments to limit lateral movement of the internal piping.

Refer to Drawing 02, “Shell Rollout” and Table 6, “Nozzles and Appurtenances” in Appendix A for nozzle location and data.

b. Fixed Roof

Fixed roof nozzles consist of two (2) 2 ½” anti-rotation cables, one (1) 36” manway with an 8” gauge hatch and internal access ladder, one (1) 6” Enraf automatic tank gauge (ATG) with an attached VITO temperature/water probe, one (1) 72” x 24” hatch, two (2) 2 ½” pan ground cables, one (1) 4” cap, one (1) 24” center vent, and one (1) 1 ½” tape level gauge penetration.

Fixed roof nozzles and reinforcement pads were examined using UTT and VT methods. Four (4)

UTT reading were taken on each nozzle with a welded connection in each of four (4) quadrants

(0°, 90°, 180°, and 270°). One (1) UTT reading was taken on each reinforcement pad. UTT readings indicated no significant metal loss on nozzles and associated reinforcement pads. The

Enraf ATG nozzle is equipped with carbon steel bolts that exhibit corrosion. The VITO temperature/water probe is provided in the same stilling well and riser as the Enraf ATG. To accurately gauge water levels within the tank, the VITO temperature/water probe should be placed as close to the tank sump as feasible. A cap located on a 1” pipe extruding the Enraf ATG riser is severely corroded exhibiting surface corrosion with metal loss.

Refer to Drawing 03, “Fixed Roof Layout” and Table 6, “Nozzles and Appurtenances” in

Appendix A for nozzle location and data.

c. Gauging

The tank is provided with an Enraf ATG system for automatic tank gauging. The Enraf ATG has a fill height label stating 33’-0”, while the strapping charts state the safe fill height as 34’-0”. The

Enraf ATG shares the same riser and stilling well as the VITO temperature/water probe. Manual gauging is performed through the gauging hatch located on the fixed roof manway. Neither the

Enraf ATG nor manual gauging hatch stilling wells are fully slotted. Stilling wells provided for the manual gauging hatch and Enraf ATG are attached directly to well guides at the tank bottom.

If the tank begins to settle, this configuration may cause icreased stress at the tank bottom. The tank is provided with a Shand and Jurs float gauge for gauging the tank volume from the ground level.

d. Level Alarms

The tank is equipped with shell-mounted independent level alarms in the high, high-high, low, and low-low level positions. The tank is provided with a HLCV shutoff for overfill protection.

e. Stairs and Platforms

The tank is provided with a spiral staircase with three (3) platforms. The first platform as for access to MW3 and the internal floating roof (IFR). The second platform is for level alarm access and maintenance. The third platform is for access to the fixed roof.

f. Grounding and Bonding

The tank is equipped with four (4) grounding lugs and cables that are in good overall condition with no signs of damage or detachment.

8. Tank Coating

All exterior and internal surfaces of the tank are coated. Coating was in good overall condition with only minor signs of failure located primarily on nozzles, appurtenances, and in the center sump with the exception of the shell-to-bottom weld which displayed disbondment.

9. Fire Protection System

For internal fire protection, Tank 2 is provided with a full contact aluminum honeycomb IFR.

10. Secondary Containment

Tank 2 is located within a concrete containment dike. Control joints for the concrete dike floor exhibit damaged (voids, cracking, disbondment, and vegetation growth) sealant. Minor signs of cracking and spalling were observed throughout the containment dike floor. Based on year of construction of the tank, it could be assumed a flexible membrane liner is provided under the tank containment; however, due to lack of as-built or construction drawings this could not be verified. In the event of a spill, the containment dike can hold approximately 40,000 BBLs. This value is approximately 127% greater than the maximum capacity of the tank.

A leak test was performed by Dark Horse on the containment dike drainage system. The leak test consisted of filling the dike drain to 3 7/16” below the drain grate and holding this volume for approximately 2 hours and 15 minutes. At the end of this time interval there was no change in height from the drain grate.

11. Internal Floating Roof

The tank is provided with an aluminum honeycomb (IFR. The IFR was provided with foam log primary and secondary seals. The foam log seals were replaced with a double wiper seal system as part of this inspection. The IFR was examined using VT methods. No gross defects nor damage were noted. The IFR is provided with six (6) support legs. Each support leg is provided with a landing pad that are sealed to the tank bottom. Two (2) mounting clips for the IFR anti-rotation cables are welded directly to the tank bottom and not provided with a fully seal welded base plate.

C. OBSERVATIONS AND RECOMMENDATIONS

The following subsections outline the itemized tank repairs/upgrades. Repairs and upgrades shall be completed IAW API 653, UFC 03-460-01, requirements and best engineering practice.

1. MANDATORY REPAIRS per API 653, UFC 3-460-01, or AW 78-24-27 Standards

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 remain OOS until these repairs are completed.

There are no mandatory repairs required to return the tank to service.

2. RECOMMENDED REPAIRS to Fully Comply with API 653, UFC 3-460-01, or AW 78-24-27

Standards

Recommended 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. These items may be required by Federal, State and Local Codes or by Military Criteria.

a. Tank Chime Sealant

OBSERVATION: Sealant provided for the tank chime displays cracking and staining.

CODE REFERENCE: UFC 3-460-03 SECTION 8-4.1.B

RECOMMENDATION: Provide approximately 5 linear feet of sealant repair at the tank chime-to-ring wall interface.

b. Pipeline Labeling

OBSERVATION: Piping within the containment dike is not provided with standard military labeling.

CODE REFERENCE: UFC 3-460-01, 2-18

RECOMMENDATION: Provide MIL-STD-161H labeling and flow arrows on the receipt and main suction line.

c. Ring Wall Control Joint

OBSERVATION: The tank ring wall-to-containment interface exhibits voids, cracking, disbondment, and vegetation growth.

CODE REFERENCE: UFC 3-460-03 SECTION 8-10.2.2 (C)

RECOMMENDATION: Provide approximately 100 linear feet (100%) of sealant repair at the tank ring wall-to-containment interface with a flexible, UV protective, and fuel resistant sealant.

d. Control Joint Sealant

OBSERVATION: Sealant provided for control joints located in the containment dike exhibit voids, cracking, disbondment, and vegetation growth.

CODE REFERENCE: UFC 3-460-03 SECTION 8-10.2.2 (C)

RECOMMENDATION: Provide approximately 50 linear feet of sealant repair at control joints within the containment dike with a flexible, UV protective, and fuel resistant sealant.

e. Containment Floor Cracking

OBSERVATION: Cracking was observed throughout the containment dike floor.

CODE REFERENCE: UFC 3-460-03 SECTION 8-10.2.2 (C)

RECOMMENDATION: Provide approximately 25 linear feet of sealant to cracking located throughout the containment dike.

f. Containment Floor Spalling

OBSERVATION: Spalling and damage was observed throughout the containment dike floor.

CODE REFERENCE: UFC 3-460-03 Section 8-10.2.2 (B)

RECOMMENDATION: Repair concrete dike floor. Existing floor exhibits approximately 10 ft2 of spalling and damage.

g. Emergency Responder Diamond

OBSERVATION: The tank is not provided with an emergency responded diamond.

CODE REFERENCE: UFC 3-460-01 2-18 (C)

RECOMMENDATION: Provide emergency responder diamond in accordance with NFPA 704.

h. Coating Failure

OBSERVATION: Coating provided for various piping, nozzles, and appurtenance displays flaking, corrosion staining, and deterioration.

CODE REFERENCE: UFC 3-460-03, Section 8-3.1

RECOMMENDATION: Provide approximately 12 ft2 of coating repair at the following piping, nozzles, and appurtenances:

• Main suction crossover piping – 2 ft2

• Receipt crossover piping – 2 ft2

• HLA, HHLA, and high level control valve (HLCV) shutoff switch – 2 ft2

• LLA and LLLA – 3 ft2

• Center sump – 1 ft2

i. Low Suction Piping

OBSERVATION: The low suction line is provided with 4” threaded piping. Threaded piping is not recommended for piping larger than 2”.

CODE REFERENCE: UFC 3-460-01, 7-5.2 (a)

RECOMMENDATION: Replace 1 linear foot of threaded piping located on the 4” low suction line.

j. Water Draw-Off Line

OBSERVATION: The water draw-off line is provided with a ball valve at the skin location. Ball valves may not provide adequate isolation during maintenance and inspection operations.

CODE REFERENCE: UFC 3-460-01, Table 8-1 (Z)

RECOMMENDATION: Replace 1” ball valve with a 1” DB&B valve on the water draw-off line.

k. Internal Shell-to-Bottom Weld

OBSERVATION: Coating along the shell-to-bottom weld displayed cracking and disbondment.

CODE REFERENCE: UFC 3-460-03, Section 8-3.2

RECOMMENDATION: Recoat 100 ft2 (100%) of internal shell-to-bottom weld.

l. Sight Flow Indicators

OBSERVATION: Sight flow indicators are located in crossover piping for the main suction and receipt line. Sight flow indicators are no longer used in this application as they present potential leak paths.

CODE REFERENCE: UFC 3-460-01 9-3.5.1

RECOMMENDATION: Remove two (2) sight flow indicators located in the crossover piping provided for the receipt and main suction lines.

m. HLA, HHLA, HLCV, LLA, and LLLA

OBSERVATION: Piping provided for the HLA, HHLA, HLCV, LLA, and LLLA and provided with threaded connections.

CODE REFERENCE: UFC 3-460-01, 7-5.2 (b)

RECOMMENDATION: Either replace the HLA, HHLA, HLCV, LLA, and LLLA piping with welded/flanged connections or seal weld existing threaded connections.

n. VITO Temperature/Water Probe

OBSERVATION: The VITO temperature/water probe shares a nozzle riser and stilling well with the Enraf ATG.

CODE REFERENCE: UFC 3-460-01, Table 8-1 (S) / DLA-E ATG Policy

RECOMMENDATION: Provide the VITO temperature/water probe with an 8” riser and 6” fully slotted stilling well as close to the center sump as feasible.

o. Enraf ATG Fasteners

OBSERVATION: Fasteners provided for the Enraf ATG flanges display coating failure and surface corrosion.

CODE REFERENCE: UFC 3-460-01, 9-8 (f)

RECOMMENDATION: Replace sixteen (16) corroded fasteners located in the Enraf ATG flange.

p. Main Suction Internal Piping

OBSERVATION: Internal piping provided for the main suction line does not turn down, and is not provided with an anti-vortex plate.

CODE REFERENCE: AW 78-24-27, D.08 (4)

RECOMMENDATION: Provide the 12” main suction line with a short radius elbow and anti-vortex plate.

q. Tell-Tale Hole

OBSERVATION: Tell-tale holes provided for nozzle reinforcement pads are opened to the atmosphere allowing water ingress, and place for insects nesting.

CODE REFERENCE: UFC 3-460-03, 8-9.13.4.1

RECOMMENDATION: Provide a heavy lithium grease to all nozzle reinforcement pad tell-tale holes to prevent water ingress.

r. Gauging Stilling Wells

OBSERVATION: Stilling wells provide for the Enraf ATG and manual gauging hatch are partially slotted, with slots only running up to initial 4 ft of the stilling well.

CODE REFERENCE: UFC 3-460-01, Table 8-1 (R)/(S) / DLA-E ATG Policy

RECOMMENDATION: Fully slot stilling wells provided for the manual gauging hatch and Enraf

ATG.

s. Anti-Rotation Cable

OBSERVATION: Two (2) anti-rotation cables are attached directly to the tank bottom via square corner attachments.

CODE REFERENCE: API 653 Figure 9-13

RECOMMENDATION: Provide two (2) circular bearing plates for both anti-rotation cables.

t. U-bolt

OBSERVATION: The main suction and low suction lines are not provided with U-bolts, used to limit lateral movement of the piping during regular operations.

CODE REFERENCE: AW 78-24-27, D.08 (6)

RECOMMENDATION: Provide one (1) stainless steel u-bolt restraint with loosened nuts for both the internal main suction and low suction line. Internal piping must be allowed to move vertically with the tank bottom.

u. Attached Stilling Wells

OBSERVATION: Stilling wells provided for the manual gauging hatch and Enraf ATG are attached directly to well guides. This attachment may cause severe damage to the tank bottom should the tank begin to settle.

CODE REFERENCE: AW 78-24-27, D.08 (6)

RECOMMENDATION: Rework stilling wells for the manual gauging hatch and Enraf ATG by removing welds attaching the stilling wells to well guides.

3. RECOMMENDED REPAIRS as Part of Regular Maintenance

Recommended 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.

a. Conduit Support

OBSERVATION: Conduit supports provided for the HLCV and visible alarm conduit is stitch-welded. Crevice corrosion and staining was observed between the conduit-to-shell interfaces.

CODE REFERENCE: BMP

RECOMMENDATION: Provide sealant or fully weld eighteen (18) stitch-welded conduit supports provided for both the HLCV conduit and the visible alarm conduit.

b. Fill Height

OBSERVATION: A white label is placed on the Enraf ATG stating a fill height of 33’-0” while the strapping charts list the safe fill height as 34’-0”.

CODE REFERENCE: BMP

RECOMMENDATION: Correct safe fill limit shown on the Enraf ATG display.

c. Pipe Cap

OBSERVATION: Cap located on piping extruding from the Enraf ATG riser displays significant surface corrosion with noticeable metal loss.

CODE REFERENCE: BMP

RECOMMENDATION: Replace corroded cap located on the 1” pipe extruding from the Enraf ATG riser.

D. INSPECTION INTERVALS

Intervals between tank inspections (both internal and external) should be determined by the tank service history, corrosion rates, and regulatory requirements. Corrosion rates can only be determined when a comparison is made between measurements taken over an interval of time. In this case, corrosion rates were determined based on the assumed nominal thicknesses and actual thickness measurements taken during this inspection.

1. Routine In-service Inspection

Facility personnel shall perform a visual inspection of the tank exterior surfaces, containment, 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 interface), coating, and appurtenances.

Interval: Monthly

2. External (In-Service) Inspection

An API certified inspector shall perform this inspection 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. This inspection includes inspection requirements of the routine in-service inspection as well as a visual inspection of the tank grounding system (shunts and cables) for damage.

Interval: Five (5) years; January 2023

3. Ultrasonic Thickness Inspection

An external UT inspection of the tank shell and roof (if applicable) shall be performed by an API certified inspector every fifteen (15) years or RCA/4N, whichever is less. The UT inspection may be performed in conjunction with the external inspection.

Interval: Fifteen (15) years; January 2033

4. Internal (Out-of-Service) Inspection

An API certified inspector shall perform the internal inspection every 20 years or ½ remaining life of the tank bottom, whichever is less. This inspection includes a visual inspection of the tank interior surfaces and associated piping and an evaluation of the tank bottom via NDT methods. Since UFC requires tank cleaning every ten (10) years, it is recommended to perform the next internal inspection at this date to further evaluate the shell-to-bottom weld.

Interval: Ten (10) years; January 2028

APPENDIX A: ENGINEERING CALCULATIONS AND DRAWINGS

21 3

8 9 10 11

12 13 14

NOTES:

1. REFER TO TABLE 1, "TANK BOTTOM PLATE ULTRASONIC

THICKNESS READINGS" IN APPENDIX A FOR INDIVIDUAL BOTTOM

PLATE UTT READINGS.

2. REFER TO TABLE 2, "TANK BOTTOM CRITICAL ZONE ULTRASONIC

THICKNESS READINGS" IN APPENDIX A FOR CIRCUMFERENTIAL

UTT READINGS.

3. REFER TO TABLE 6, "NOZZLES AND APPURTENANCES", IN

APPENDIX A FOR NOZZLE DATA.

C O

N T

R A

C T

N

O

F I L

E

N

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

4 5

A

B

M A

R K

A P

P R

D A

T E

F I L

E

N

U M

B E

R

S I Z

E

S U

B M

I T

T E

D

B

Y

P L

S

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

E R

SHEET

IDENTIFICATION

D A

T E

A P

P R

SHEET OF

N T

S

N A

W

F

F

X

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

J G

C

K B

B

N A

TANK INFORMATION

TANK NO. (FACILITY NO.): 2 (3474)

MANUFACTURER: WITHERUP FABRICATION AND ERECTION, INC.

YEAR BUILT: 2005

TANK DIAMETER: 31'-0"

TANK HEIGHT: 41'-3"

MAX FILL CAPACITY: 5,000 BBLS

PRODUCT: JET-A (F-24)

PRODUCT SPECIFIC GRAVITY: 0.85

GPS COORDINATES: N 38° 48' 56.16"

W 76° 51' 28.67"

U S

A C

E

O M

A H

A

D

I S

T R

I C

T

J O

I N

T

B

A S

E

A

N D

R E

W S

M

A R

Y L

A N

D

A N

D R

E W

S

A

F B

T A

K

L

A Y

O U

T

N A

W

F

D

J R

D

ANTI-ROTATION

CABLE (TYP. 2)

LADDER

LOW SUCTION

(N7)

WATER

DRAW-OFF

(N9)

STRIKER PLATE FOR IFR

SUPPORT LEG (TYP. 6)

RECEIPT

(N10)

MAIN SUCTION

(N8)

MW2

MW1

PIPE SUPPORT

(TYP. 4)

ENRAF ATG

STILLING WELL

(N12)

MANUAL

GAUGING HATCH

STILLING WELL

(MW4)

SUMP DETAIL

0.499"

0.483" 0.498"

0.499"

0' 9"

0.483"

0.515"

0.484"

0.517"

0.483"

2' 5"

.XXX"

LEGEND

- UTT READING

- COATING FAILURE

B O

T T

M

Y

O U

T

PIPE SUPPORT

(TYP. 3)

Table 1: Tank Bottom Ultrasonic Thickness Readings

Plate 1 Plate 2 Plate 3 Plate 4 Plate 5

.306 .306 .316 .315 .307 .305 .309 .305 .302 .302

.303 .316 .304 .315 .303

.306 .305 .310 .316 .306 .305 .312 .315 .304 .302

Avg. .305 .315 .305 .311 .303

Plate 6 Plate 7 Plate 8 Plate 9 Plate 10

.309 .306 .303 .304 .301 .303 .302 .312 .310 .306

.311 .304 .305 .317 .304

.308 .309 .300 .301 .301 .303 .310 .313 .304 .307

Avg. .309 .302 .303 .311 .306

Plate 11 Plate 12 Plate 13 Plate 14

.306 .312 .299 .301 .311 .311 .304 .304

.317 .303 .313 .306

.316 .314 .305 .312 .314 .303 .306 .305

Avg. .313 .304 .310 .305 Thickness reading in inches.

Average tank bottom thickness reading: 0.307” Refer to Drawing 01, Bottom Layout, for plate layout.

Table 2: Tank Bottom Critical Zone Ultrasonic Thickness Readings

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

.300 .306 .302 .307 .319 .323 .320 .313 .310 .299 .307 .311 .310 .309 .309 .309 .319

34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66

.319 .320 .309 .309 .310 .307 .309 .312 .303 .306 .300 .303 .316 .319 .314 .316 .317

68 70 72 74 76 78 80 82 84 86 88 90 92 94 96

.306 .311 .309 .308 .304 .302 .313 .315 .314 .318 .311 .306 .309 .306 .301

Thickness readings are in inches.

Average tank bottom critical zone plate thickness reading: 0.310” Refer to Drawing 01, Bottom Layout, for plate layout and UTT reading locations.

0’ = directly below manway opening.

Thickness readings were taken within 3” of the shell-to-bottom weld proceeding clockwise around the tank.

STORAGE TANK FLOOR EVALUATION

Date 01/31/2018

MINIMUM REMAINING THICKNESS (MRT) CALCULATIONS

File No Report No Client Inspector Tank No Temp (degF)

Andrews AFB Tank 2

(3474) USACE Omaha

John Cronin

(POND)

Tank 2 (3474)

Liner CP Protec 50mil Liner RPB Ca Shell tmin

Shell tnom D H

Yes Yes No N/A 0.188 0.101 0.250 31.000 37.583

Where;

Ca = corrosion allowance, in (inch).

MRT = minimum remaining thickness at the end of interval Or. This value must meet the requirements of Table 4-1 and sections 2.4.7.4 and 2.4.8.

Or = In-service interval of operation (years to next internal inspection) not to exceed that allowed by 4.4.2.

RTbc = minimum remaining thickness from bottom side corrosion after repairs.

RTip = minimum remaining thickness from internal corrosion after repairs.

StPr = maximum rate of corrosion not repaired on the top side. StPr = 0 for coated areas of the bottom.

The expected life of the must equal or exceed Or to use StPr = 0.

tmin = minimum allowable thickness in accordance with requirements of Table 4-1 and sections 2.4.7.4 and 2.4.8.

to = bottom plate original thickness.

UPr = maximum rate of corrosion on the bottom side. To calculate the corrosion rate, use the minimum remaining thickness after repairs. Assume a linear rate based on the age of the tanks. UPr = 0 for areas that have effec D = nominal diameter of tank, in (ft), H =Height, in (ft), from the bottom of the 1st shell course to the maximum allowable fill height S=Stresses are calculated from 2.6(H-1)DG/SE.

GENERAL PLATES-AFTER INSPECTION / REPAIRS

Age to RTbc RTip UPr StPr Or MRT tmin Results

13 0.313 0.307 0.307 0.00000 0.00000 20 0.307 0.100 ACCEPTABLE

PLATES IN CRITICAL ZONE (3") - AFTER INSPECTION / REPAIRS

Age to RTbc RTip UPr StPr Or MRT tmin Results

13 0.313 0.310 0.310 0.00000 0.00000 20 0.310 0.100 ACCEPTABLE

croninj Typewritten Text Nominal thickness was assumed to be 0.3125" (5/16").

API-653 APPENDIX B SHELL SETTLEMENT EVALUATION

(para. B.2.2.4)

Report No Client Inspector Vessel Date Andrews AFB Tank

2 (3474) USACE Omaha John Cronin (POND) Tank 2 (3474) 02/06/2018

Base Elev Max Elev Elev

FT 0.458 0.479 0.021 R^2 = 0.960

IN 5.496 5.748 0.252

API-653 APPENDIX B SHELL SETTLEMENT EVALUATION

Report No.: Andrews AFB Tank 2 (3474)

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

31 41.3 F 9.74 A 36 36000 29000000

Where:

D = Tank Diameter, in ft H = Tank Height, in ft Roof Type: F = fixed, O = Open L = Arc length between measurement points, in ft (32' max) (greatest dist. allowed based on even # of points) Y = Yield strength of shell 1st course , in pounds per Sq.Inch (psi) E - Young's modulus, in pounds per Sq.Inch (psi)

= Angle theta at elevation point, in degrees PE = Predicted elevation, in ft Ui = Measured out-of-plane settlement in relation to a cosine curve, in ft Si = Deflection, in ft, (out-of-plane distortion) Smax = Maximum allowed deflection, in ft, (out-of-plane distortion)

Smax =((L^2*Y*11)/2*(E*H)) = 0.016

Point Elevation PE Ui Si Results

1 0.458 0 0.460 -0.002 0.002 SAT

2 0.458 36 0.465 -0.007 -0.005 SAT

3 0.469 72 0.472 -0.003 0.000 SAT

4 0.479 108 0.477 0.002 0.003 SAT

5 0.479 144 0.479 0.000 -0.002 SAT

6 0.479 180 0.477 0.002 0.003 SAT

7 0.469 216 0.472 -0.003 0.000 SAT

8 0.458 252 0.465 -0.007 -0.005 SAT

9 0.458 288 0.460 -0.002 0.002 SAT

10 0.458 324 0.458 0.000 0.002 SAT

Table 3: Tank Bottom Elevation Measurements

Point Arc Length (ft.) 0'-2" 10'-0" 15'-0"

1 0.00 .458 1.083 1.271

2 9.74 .458 1.042 1.271

3 19.48 .469 1.000 1.271

4 29.22 .479 .948 1.271

5 38.96 .479 1.052 1.260

6 48.69 .479 1.063 1.271

7 58.43 .469 1.010 1.271

8 68.17 .458 .854 1.271

9 77.91 .458 OBS 1.271

10 87.65 .458 1.000 1.271

Point 1 is located at Manway 1 and subsequent points are measured clockwise circumferentially every 9.74’.

8'-0"

8'-0"

8'-0"

8'-0"

9'-3"

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

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

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

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

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

NOTES:

1. REFER TO TABLE 5, "SHELL PLATE ULTRASONIC THICKNESS READINGS", IN APPENDIX A FOR

INDIVIDUAL SHELL PLATE UTT READINGS.

2. REFER TO TABLE 6, "NOZZLES AND APPURTENANCES", IN APPENDIX A FOR NOZZLE DATA.

C O

N T

R A

F I L

E

N

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

4 5

A

B

M A

R K

A P

P R

D A

T E

F I L

E

N

U M

B E

R

S I Z

E

S U

B M

I T

T E

D

B

Y

P L

S

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

E R

SHEET

IDENTIFICATION

D A

T E

A P

P R

SHEET OF

N T

S

N A

W

F

F

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

J G

C

K B

B

N A

TANK INFORMATION

TANK NO. (FACILITY NO.): 2 (3474)

MANUFACTURER: WITHERUP FABRICATION AND ERECTION, INC.

YEAR BUILT: 2005

TANK DIAMETER: 31'-0"

TANK HEIGHT: 41'-3"

MAX FILL CAPACITY: 5,000 BBLS

PRODUCT: JET-A (F-24)

PRODUCT SPECIFIC GRAVITY: 0.85

GPS COORDINATES: N 38° 48' 56.16"

W 76° 51' 28.67"

U S

A C

E

O M

A H

A

D

I S

T R

I C

T

J O

I N

T

B

A S

E

A

N D

R E

W S

M

A R

Y L

A N

D

A N

D R

E W

S

A

F B

T A

K

Y

O U

T

N A

W

F

D

J R

D

N5

N6

N1

N2

N3

N4

MW1

S H

E L

L

R

O L

L O

U T

MW2

N7

N8

N9

N10

MW3

CONDUIT SUPPORT

(TYP. 6)

CONDUIT SUPPORT (TYP. 8)

CONDUIT SUPPORT (TYP. 14)

TAPE LEVEL GAUGE SUPPORT (TYP. 4)

SPIRAL

STAIRCASE

(TYP.)

GROUNDING CABLE

(TYP. 4)

PERIMETER HANDRAIL

TANK FOUNDATION

OVERFLOW PORT

(TYP.4)

Table 4: Shell Plate Ultrasonic Thickness Readings

Roof

Shell Course

Plate 5-1 Plate 5-2 Plate 5-3 Plate 5-4

.277 .266 .280

.269 .265 .275 N/A N/A N/A

.267 .261 .278

Avg. .271

Circumferential Weld C5

Shell Course

Plate 4-1 Plate 4-2 Plate 4-3 Plate 4-4

.284 .285 .309

.288 .295 .288 N/A N/A N/A

.294 .274 .300

Avg. .291

Circumferential Weld C4

Shell Course

Plate 3-1 Plate 3-2 Plate 3-3 Plate 3-4

.304 .270 .277

.286 .271 .283 N/A N/A N/A

.284 .271 .302

Avg. .266

Circumferential Weld C3

Shell Course

Plate 2-1 Plate 2-2 Plate 2-3 Plate 2-4

.274 .285 .297

N/A N/A N/A .270 .284 .285

.269 .278 .285

Avg. .281

Circumferential Weld C2

Shell Course

Plate 1-1 Plate 1-2 Plate 1-3 Plate 1-4 Plate 1-5

.276 .284 .288 .286 .296 .310 .306 .309 .276 .288 .310 .279 .288 .292 .280

.285 .283 .282 .282 .283 .308 .305 .321 .287 .289 .297 .278 .274 .284 .277

.281 .280 .279 .290 .279 .285 .298 .317 .271 .296 .281 .275 .275 .298 .276

Avg. .282 .291 .299 .288 .283

Circumferential Weld C1

Thickness readings are in inches.

Shell Course 1 Average: 0.289” Shell Course 2 Average: 0.281” Shell Course 3 Average: 0.266” Shell Course 4 Average: 0.291” Shell Course 5 Average: 0.271” Refer to Drawing 02, Shell Rollout, for shell layout.

SHELL MINIMUM THICKNESS CALCULATIONS

Tank Shell Minimum Thickness and Remaining Life Calculations Date 02/06/2018

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

1908 Andrews AFB Tank 2 (3474)

USACE Omaha Tank 2 (3474) John Cron 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) 31 G 0.85 E 1.00 Fill Height (ft) 37.6

Material Crs H (ft) H (ft) S (psi) tmin (inch) Course 1 A 36 9.25 37.6 24900 0.101 Course 2 A 36 8 28.3 24900 0.100 Course 3 A 36 8 20.3 27400 0.100 Course 4 A 36 8 12.3 27400 0.100 Course 5 A 36 8 4.3 27400 0.100

SHELL REMAINING LIFE CALCULATIONS

Tank Shell Minimum Thickness and Remaining Life Calculations Date 02/06/2018

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

1908 Andrews AFB Tank 2 (3474)

USACE Omaha Tank 2 (3474) John Cron

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

Y = 13 = 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 0.289 0.101 0.188 0.0000 >40 106.04 Course 2 0.250 0.281 0.100 0.181 0.0000 >40 112.38 Course 3 0.250 0.266 0.100 0.166 0.0000 >40 124.63 Course 4 0.250 0.291 0.100 0.191 0.0000 >40 142.63 Course 5 0.250 0.271 0.100 0.171 0.0000 >40 142.63

1ST SHELL COURSE (0'-3"):

16'-2"

MW2

1ST SHELL COURSE (3'-0"):

1ST SHELL COURSE (6'-0"):

30'-11

30'-11

30'-11

MW1

30'-10

31'-

30'-11

MW2

MW1

MW2

MW1

30'-10

30'-11

30'-11

Table 5: Fixed Roof Ultrasonic Thickness Readings

Plate 1 Plate 2 Plate 3 Plate 4 Plate 5

.295 .293 .288 .275 .298 .298 .294 .288 .289 .286

.300 .274 .297 .288 .301

.294 .284 .271 .281 .291 .295 .282 .292 .297 .283

Avg. .293 .278 .296 .289 .291

Plate 6 Plate 7 Plate 8 Plate 9 Plate 10

.293 .308 .305 .289 .281 .304 OBS OBS .290 .291

.286 .299 .297 OBS .300

.286 .298 .291 .285 .298 .291 OBS OBS .281 .293

Avg. .294 .294 .294 .291 Thickness readings are in inches.

Average fixed roof plate thickness reading: 0.291”

OBS - Obstructed

Refer to Drawing 03, Fixed Roof Layout, for fixed roof layout and UTT reading locations.

AST ATMOSPHERIC STORAGE TANK FIXED ROOF EVALUATION

MINIMUM THICKNESS, REMAINING LIFE, PRESSURE CALCULATIONS

Date 02/06/2018

File No Report No Client Inspector Tank No Temp(degF)

Andrews AFB Tank 2

(3474) USACE Omaha John Cronin (POND) Tank 2 (3474)

Where;

Ca = remaining corrosion allowance of the tank component under consideration, in inch (t act - t min).

Cr = corrosion rate of the tank component under consideration, in inch per year (t prev - t act / Y).

oz = unit of measurement, (weight, in ounces, per square inch), (16 oz per pound) psi = unit of measurement, (weight, in pounds, per square inch) RL = estimated remaining life of the tank component under consideration, in year (Ca / Cr).

t act = actual thickness measurement of the tank component under consideration, as recorded at the time of inspection, in inch.

t min = minimum required thickness of tank component, at the design MAWP at the design temperature (200 degF for atm AST's), in inch (greater of psi/wt or 0.090").

t nom = design nominal thickness of tank component under consideration, in inch.

t prev = previous thickness measurement of the tank component under consideration, as recorded at last inspection or nominal thickness if no previous thickness measurements, in inch.

t yn = thickness of the tank component under consideration at the next inspection at twice the calculated corrosion rate, in inch (t act - (2*Cr*Yn).

wt = weight of plate per cubic inch.

wc = unit of measurement, (height, in inch, of water column bearing on 1 Sq.Inch area), (27.7 wc per pound) Y = time span between thickness readings or age of the tank component if tnom is used for tprev, in year.

Yn = estimated time span to next inspection of the tank component under consideration, in year.

ROOF PLATES - REMAINING LIFE

Y t prev (inch) t act (inch) t min (inch) Cr (inch/Yr) Ca (inch) RL

13 0.313 0.291 0.090 0.00169 0.201 119 croninj Typewritten Text Nominal thickness was assumed to be 0.3125" (5/16").

Table 6: Nozzle and Appurtenances

Nozzle Nozzle Size

(Diameter or Width/Height)

Repad Shape

RepadSize (W X H)

Repad Thickness

Nozzle Thickness

H1 H2

Nozzle Location (Measured circumferentially from Manway A)

Notes 0° 90° 180° 270°

MW1 36" B 6'-0" .298 .425 .413 .410 - 3'-3" 0'-6" 0' Manway

N1 1 1/2" - - - TH TH TH TH 39'-10" - 9'-6" HHLA

N2 1 1/2" - - - TH TH TH TH 36'-1" - 9'-6" HLA

N3 1 1/2" - - - TH TH TH TH 39'-4" - 12'-9" HLCV Shutoff

N4 1 1/2" - - - TH TH TH TH 37'-8" - 12'-9" HLCV Shutoff

N5 1 1/2" - - - TH TH TH TH 3'-0" - 12'-9" LLA

N6 1 1/2" - - - TH TH TH TH 1'-6" - 12'-9" LLLA

MW2 36" B 6'-0" .261 .410 .412 .390 .408 3'-8" 0'-6" 49'-0" Manway

N7 4" B 1'-0" .273 .303 .329 .313 .323 0'-10" 0'-4" 61'-3" Low Suction

N8 12" B 2'-2" .275 .532 .526 .515 .535 1'-5" 0'-5" 65'-1" Main Suction

MW3 36" B 6'-0" .283 .419 .399 .394 .399 9'-4" 6'-4" 79'-0" Manway

N9 1 1/2" - - - .251 - - - 0'-6" - 87'-0" Water Draw-Off

N10 8" B 1'-7" .271 .530 .498 .533 - 1'-6" 0'-9" 89'-7" Receipt

N11 2 1/2" - - - TH TH TH TH Fixed Roof Anti-Rotation Cable

MW4 36" B 4'-6" .273 .265 .242 .255 .257 Fixed Roof Manway w/ 8" Gauge Hatch

N12 6" B 1'-3" .290 .267 .273 .289 .262 Fixed Roof Enraf ATG / VITO Temp/Water Probe

N13 72" x 24" - - - .414 .435 .403 .424 Fixed Roof Hatch

N14 2 1/2" - - - TH TH TH TH Fixed Roof Pan Ground

N15 4" B 0'-9" .372 .267 .270 .278 .276 Fixed Roof Cap

N16 24" B 2'-9" .235 .276 .283 .280 .296 Fixed Roof Center Vent

N17 2 1/2" - - - TH TH TH TH Fixed Roof Pan Ground

N18 2 1/2" - - - TH TH TH TH Fixed Roof Anti-Rotation Cable

N19 1 1/2" - - - TH TH TH TH Fixed Roof Shand and Jurs Tape Level Gauge

Thickness measurements are in inches.

H1 = C/L of pipe to edge of roof or chime H2 = Edge of tank or chime to nearest weld toe.

TH = Threaded Repad Shapes:

Table 7: Dry Film (Coating) Thickness

External Shell Coating Thickness

Average Standard Deviation Number of Readings Minimum Maximum

12.380 2.879 23 8.169 20.000

Internal Shell Coating Thickness

27.450 5.998 14 18.700 36.950

Bottom Coating Thickness

16.270 4.130 15 9.624 24.970

Fixed Roof Coating Thickness

15.200 3.546 13 12.330 23.860

Readings are represented in mils.

APPENDIX B: API 653 CHECKLISTS FOR TANK INSPECTIONS

Tank In-Service Inspection Checklist

Item Completed

X

B.1.1 Foundation a Measure foundation levelness and bottom elevations (see Annex B for extent of measurements).

X

B.1.1.1 Concrete Ring a Inspect for broken concrete, spalling, and cracks, particularly under backup bars used in welding butt-welded annular rings under the shell.

X b Inspect drain openings in ring, back of waterdraw basins and top surface of ring for indications of bottom leakage.

X c Inspect for cavities under foundation and vegetation against bottom of tank. X d Check that runoff rainwater from the shell drains away from tank. X e Check for settlement around perimeter of tank. X

B.1.1.2 Asphalt a Check for settling of tank into asphalt base which would direct runoff rain water under the tank instead of away from it.

N/A b Look for areas where leaching of oil has left rock filler exposed, which indicates hydrocarbon leakage.

N/A

B.1.1.3 Oiled Dirt or Sand a Check for settlement into the base which would direct runoff rain water under the tank rather than away from it.

N/A

B.1.1.4 Rock a

Presence of crushed rock under the steel bottom usually results in severe underside corrosion. Make a note to do additional bottom plate examination (ultrasonic, hammer testing, or turning of coupons) when the tank is out of service.

N/A

B.1.1.5 Site Drainage a Check site for drainage away from the tank and associated piping and manifolds. X b Check operating condition of the dike drains. X

B.1.1.6 Housekeeping a Inspect the area for buildup of trash, vegetation, and other inflammables buildup. X

B.1.1.7 Cathodic Protection a Review cathodic protection potential readings. X

B.1.2 Shells

B.1.2.1 External Visual Inspection a Visually inspect for paint failures, pitting, and corrosion. X

Item Completed

X b Clean off the bottom angle area and inspect for corrosion and thinning on plate and weld.

X c Inspect the bottom-to-foundation seal, if any. X

B.1.2.2 Internal (Floating Roof Tank) a Visually inspect for grooving, corrosion, pitting, and coating failures. N/A

B.1.2.3 Riveted Shell Inspection a Inspect external surface for rivet and seam…