Attachment J.1 - DOV-FY20-FAC 734-Tank 734-FINAL.pdf

US Army Corps of Engineers Omaha District

API 653 In-Service Inspection Report

Dover Air Force Base, Delaware Tank Facility 734

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

USACE POL-MCX

30 Jan 2020

API 653 In-Service Inspection Report Dover AFB, Delaware

Table of Contents

ACRONYMS AND ABBREVIATIONS

EXECUTIVE SUMMARY AND SUITABILITY FOR CONTINUED SERVICE

THIS INSPECTION

PREVIOUS INSPECTION DATES

STATE REGULATIONS

RECOMMENDED FUTURE INSPECTION DATES

A. GENERAL PROJECT INFORMATION

1. SPCC Mandated AST Inspections

2. Site Information

3. Previous Inspection and Repairs

4. Future Projects

B. TANK INSPECTION COMMENTS

1. Tank Construction

2. Tank Foundation

3. Tank Bottom

4. Tank Roof

5. Tank Shell

6. Tank Appurtenances

7. Tank Coating

8. Tank Piping System

9. Fire Protection System

10. Secondary Containment

11. Cathodic Protection

GENERAL TANK INFORMATION

C. FINDINGS AND RECOMMENDATIONS

1. MANDATORY REPAIRS per API 653, NFPA, or CFRs

2. SHORT TERM RECOMMENDATIONS

APPENDIX ‘A’: ENGINEERING CALCULATIONS AND DRAWINGS

SHELL THICKNESS CALCULATIONS

SHELL AND ROOF ULTRASONIC THICKNESS MEASUREMENTS

SHELL SETTLEMENT ANALYSIS

TANK DRAWINGS

OSHA ACCESS STRUCTURE REPORT

APPENDIX ‘B’: API 653 CHECKLISTS FOR TANK INSPECTIONS

APPENDIX ‘C’: PHOTOGRAPHS

ACRONYMS AND ABBREVIATIONS

API American Petroleum Institute

AFFF Aqueous Film Forming Foam

ASME American Society of Mechanical Engineers

ASNT American Society of Non-Destructive Testing

ATG Automatic Tank Gauge

BBL Barrel

CC Carbon Steel

CFR Code of Federal Regulations

CP Cathodic Protection

CS Carbon Steel

DFT Dry Film Thickness

FAC Facility

HLA High Level Alarm

HLCS High Level Control Shutoff

HHLA High-High Level Alarm

LLA Low Level Alarm

LLLA Low-Low Level Alarm

MFL Magnetic Flux Leakage

MT Magnetic Particle Testing

NA Not Applicable

NACE National Association of Corrosion Engineers

NDT Non-Destructive Testing

NFPA National Fire Protection Association

PSI Pounds per Square Inch

PT Penetrant Testing

PTFE Polytetrafluoroethylene (e.g., TEFLON)

P/V Pressure/Vacuum

PST Product Saver Tank

SS Stainless Steel

TRV Thermal Relief Valve

UFC Unified Facilities Criteria

UFGS Unified Facilities Guide Specifications

UG Underground

UT Ultrasonic Testing

EXECUTIVE SUMMARY AND SUITABILITY FOR CONTINUED SERVICE

Austin Brockenbrough & Associates, LLC (Brockenbrough) was retained by Omaha District USACE under Contract

No. W9128F-17-D-0017 Delivery Order W9128F20F0024 to perform SPCC Mandated AST/UST Inspections at various locations. As required by this task, Brockenbrough executed a tank inspection site visit to Dover Air Force

Base, Dover, Delaware. An API 653 In-service (visual external) Inspection was conducted for Facility No. 734, on

January 30, 2020. This inspection was performed in accordance with API Standard 653, “Tank Inspection, Repair, Alteration, and Reconstruction,” and the referenced contract. The inspection included a tank foundation settlement evaluation and UT inspection of the shell and roof. All observations made during this in-service (visual external) inspection were made from the exterior of the tank.

Facility 734 is a 100-foot diameter by 40-foot 6-inch tall, single wall, vertical, field-erected tank with a nominal storage capacity of 51,370 barrels (per dataplate) of Jet A (F-24). A tank erector’s nameplate could not be found.

The repair contractor’s nameplate and completion report indicates the tank was constructed to API 650 in 1970 and that the second bottom, stilling wells for manual gauging and the water probe, Petrex aluminum internal floating pan, 36-inch shell and roof manholes, internal ladder, receipt, issue and water draw-off nozzles, product saver tank, internal piping, and level alarms were installed in 2010. Details of tank construction and appurtenances are included in the Tank Information Table on in Section ‘B’.

This tank was found to be in generally good condition, fully serviceable, with no mandatory repairs noted, and suitable for continued service. However, the dike liner has passed the end of its useful service life and should be replaced as soon as practical. Additional noted deficiencies are discussed in more detail in Section ‘C’ and should be addressed in a timely manner. Photographs of the tank are included in Appendix ‘C’.

Delaware aboveground storage tank regulations require in-service and out-of-service inspections to be performed at intervals in accordance with API 653. The next API In-service (external) inspection of Tank 734 should be performed by January 2025. The next ultrasonic thickness inspection of the shell should be performed by January

2035. API 653 recommends the next out-of-service (internal) inspection be performed within 30 years of initial service of a new tank bottom with an internal coating, leak detection, secondary containment, cathodic protection, and extra corrosion allowance. However, current military practice limits the inspection interval to 20 years.

Therefore, the next API 653 Out-of-service (internal) inspection should be performed by June 2030. The inspection should include an examination of the tank bottom by magnetic flux leakage (MFL or MFE) technology and a thorough code compliance evaluation.

THIS INSPECTION

API In-Service (External) Inspection Date: 30 January 2020

Equipment Used:

Shell Settlement Survey Equipment

Rotary Laser Level: CST/berger Model: ALHV Calibrated: Self -leveling

Ultrasonic Thickness Gauge

Manufacturer: NDT Systems Model Number: Nova TG110-DL Probe: 560P (Thru-paint) Calibration Method: Calibration Block NDT Technician (s): Mike O’Connor

Inspector(s): Mike O’Connor

PREVIOUS INSPECTION DATES

API Out-of-Service (Internal) Inspection Date: NA API In-Service (External) Inspection Date: October 2015

STATE REGULATIONS

State Regulation for API In-Service Tank Inspections January 2025 State Regulation for API Out-of-Service Tank Inspections June 2040

RECOMMENDED FUTURE INSPECTION DATES

API Out-of-Service (Internal) Inspection Date: June 2030 API Ultrasonic Thickness Inspection of Shell Date: January 2035 API In-Service (External) Inspection Date: January 2025

Mike O’Connor Mechanical Designer API 653 Inspector No. 6230

A. GENERAL PROJECT INFORMATION

1. SPCC Mandated AST Inspections

This project will perform API 653 and STI SP001 inspections of various tanks at facilities throughout the United States. The specific inspection performed is based on available information on the tank type, product being stored, and recommendations from previous inspection reports (if available). Additional consideration is given to federal, state, and local regulations, as well as applicable military criteria and general industry standards. For this Task Order, Brockenbrough performed Inspection of Facilities

734, 756, and 757 located at Dover Air Force Base, Delaware. For the Tank Facility 734, an API 653 In-service (external) Tank Inspection was performed on January 30, 2019. The inspection included a shell settlement survey and a shell UT inspection.

2. Site Information

Dover Air Force Base is located in Dover, Delaware. The 436th Airlift Wing (AW), a subordinate of

Eighteenth Air Force also known as the "Eagle Wing," is the active duty military host unit for the Base.

Eagle Wing consists of operations, maintenance, mission support and medical groups and has more than 4,000 active-duty military and civilian employees. Dover Air Force Base is also home to the Air

Force Reserve’s 512th Airlift Wing, whose mission is to assist with maintenance and operation of the C-

5M and C-17 aircraft assigned to the 436th AW. The 436th and 512th AWs fly hundreds of missions throughout the world, providing movement of outsized cargo and personnel on scheduled, special assignment, exercise, and contingency airlift missions. Together, they account for 20 percent of the nation's strategic outsized airlift capability and fly to more than 100 countries.

3. Previous Inspection and Repairs

A 2010 completion report indicates the second bottom, stilling wells for manual gauging and the water probe, 36-inch shell and roof manholes, internal ladder, Petrex aluminum internal floating pan, receipt, issue and water draw-off nozzles, product saver tank, internal piping, and level alarms were installed in

2010. An in-service inspection was performed in October 2015.

4. Future Projects

Facility personnel report there are currently no projects scheduled for execution in the future that affect the operation of the tank.

B. TANK INSPECTION COMMENTS

1. Tank Construction

Tank Facility 734 is an aboveground, vertical, storage tank, measuring 100 feet in diameter and 40 feet and 6 inches tall, and with a nominal capacity of 51,370 BBLs (per repair contractor’s nameplate). The capacity of the tank from the bottom of shell to the overflow is approximately 53,500 BBLs. The tank manufacturer’s nameplate could not be found. However, the repair contractor’s nameplate and the repair completion report indicate the tank was constructed to API 650 in 1970.

2. Tank Foundation

The perimeter of the bottom rests on a generally at-grade concrete ringwall. Due to lack of projection above grade and the tank bottom covering most of the top of the ringwall, only a small strip of the ringwall, measuring approximately 1 inch wide, is exposed for examination. No cracks were observed in the exposed areas of the ringwall. However, erosion has left the aggregate exposed. A shell settlement survey was performed during the inspection in accordance with Appendix ‘B’ of API

Standard 653. The shell settlement evaluation indicates the settlement of the bottom of the shell and perimeter of the tank bottom is acceptable.

3. Tank Bottom

The 2010 completion report indicates the cone-down bottom is made of 5/16-inch lap-welded plate.

4. Tank Roof

The tank roof is a lap-welded cone roof, constructed of steel plate. There are bird droppings on the roof and roof perimeter guardrails. There is corrosion on the internal floating pan installation hatch and where a conduit support channel for the water probe is broken loose from the glue.

5. Tank Shell

The vertical and cylindrical shell consists of five butt‐welded courses. The ultrasonic thickness measurements of the shell and calculations, included in Appendix ‘A’, indicate the shell has more than

30 years of remaining life. API 653 recommends ultrasonic thickness measurements of the shell be taken at least every 15 years. The exterior of the shell was visually inspected and evaluated for peaking and banding. Little peaking and banding of the butt-welded shell seams were observed. The peaking-and-banding appeared to be within limits allowed by API 650.

6. Tank Appurtenances

a. Gauging

The tank’s Honeywell Enraf ATG is installed through an 8-inch roof nozzle consisting of a threaded carbon steel coupling. According to the 2010 repair drawing, an 8‐inch fully slotted aluminum ATG well is hung from the threaded carbon steel coupling inside of the tank. The 8-inch aluminum manual gauge well is mounted through a 10-inch flanged roof nozzle and is fitted with a floating plug retriever. A Vito water probe is installed through a 4-inch aluminum well mounted through a flanged 6-inch roof nozzle, which is located over the off-center tank bottom sump. The tank also has a Shand and Jurs autogauge, which is not consistent with the ATG. Contrary to manufacturer’s instructions, the tape is attached directly to the internal floating pan, which often results in damage to the autogauge and inconsistent level readings.

b. Level Alarms

The tank has shell mounted (independent) high, high-high, and low-low level alarms. The tank also has redundant ATG alarms as well as alarms actuated by the autogauge.

c. Stairs and Platforms

The tank’s steel cone roof is accessible by a circumferential stairway mounted on the shell of the tank. The circumferential stairway step rise is generally 9 inches continuously from approach landing level to the top landing. The width of the stair steps is generally 28 inches. The measured height of the stairway handrail is 32 inches. The approach landing to the circumferential stairway is accessible by a stairway mounted radially to the tank. The radial approach step rise is generally

10 1/2 inches continuously from bottom step to the approach landing, but the rise from ground level to the bottom step is only 9 inches due to 1 1/2-inch thick pavers being placed on the dike liner at the bottom of the approach steps. The width of the approach steps is generally 43 inches.

The measured height of the approach stairway handrail is 30 inches.

d. Grounding and Bonding

While there are numerous grounding lugs on the dead shell (shell below the new tank bottom), there appears to be only three grounding cables not associated with the cathodic protection system, and they are bolted to lugs and not exothermic welded.

e. Roof Manhole

Entry to the internal ladder is gained through a 36-inch round roof hatch. The hatch does not have a rain lip and there is corrosion on the mating surfaces of the flange and cover plate. The round hatch does not provide 30 inches of clearance on the climbing side of the ladder as required by

OSHA.

f. Roof Inspection Hatches

There are three 24-inch round inspection hatches on the roof. API 650 H.5. currently requires that, when specified by the purchaser, a minimum of four inspection hatches be provided for a tank of this size, and this matches the current UFC 3-460-01 and DoD Standard Design AW 78-24-26.

However, as the inspection hatches may have met the applicable standard at the time of construction, and there are at least some inspection hatches, no recommendation to upgrade the hatches to the current standard is made at this time.

g. Venting

The tank venting is covered with screens with 1/4-inch openings. API 650 requires screens with

1/2-inch openings to reduce the chance of clogging or freezing over. The peripheral venting is provided by 30 vent slots at the top of the shell. The vent slots appear to satisfy the requirements of API 650. However, the vent slots have a different appearance from those included the guidance for new construction provided in UFC 3-460-01 and DoD Standard Design AW 78-24-27. Other than replacing the vent screens to increase the size of the openings, no recommendation to upgrade the vents to the current standard is made at this time.

7. Tank Coating

The tank’s coatings were evaluated for deterioration. The exterior of the shell and roof show little sign of significant deterioration. However, there is a considerable amount of bird droppings on the roof and roof guardrails, which could result in deterioration. There is also corrosion on the internal floating pan installation hatch and where a conduit support channel for the water probe is broken loose from the glue. The mating surfaces of the flange and cover of the 36-inch round internal ladder access roof hatch is also corroded.

8. Tank Piping System

Facility 734 is a bulk storage tank. Fuel is primarily received from a commercial pipeline through the nearby filter house. Fuel is issued from the tank to the hydrant system tanks. Except for the aluminum level control valve, the fuel system piping inside the dike area is aboveground and carbon steel. There appears to be adequate thermal relief throughout the piping system. However, the receipt piping thermal relief valve is set at 75 psi, which may be less than the receipt pressure and could result in slight but continuous bypass filling and premature failure (washout) of the thermal relief valve.

9. Fire Protection System

There are five fire hydrants within 300 feet of the tank.

10. Secondary Containment

Secondary containment consists of an earthen berm with concrete cover and a flexible membrane liner system covering the concrete on the interior of the berms and the secondary containment basin. The secondary containment was evaluated during the inspection. The containment is of sufficient size to contain a total tank loss plus nearly 2 feet of freeboard. However, there are numerous holes and patches in the dike liner. The dike liner fabric is exposed in many places. The liner has reached the end of its useful life. The secondary containment is not impervious as required by state and federal regulations.

11. Cathodic Protection

Impressed current cathodic protection anodes and sand between the FML liner and the tank bottom was installed with the 2010 tank bottom replacement. The analogue indicators on the rectifier indicated the rectifier had normal output voltage and current. The December 2019 annual cathodic protection survey report also indicated that the cathodic protection system was working properly.

GENERAL TANK INFORMATION

ITEM DESCRIPTION

Owner United States Air Force

Location Dover Air Force Base

Facility Number 734

Tank Number Tank 734

State / Country Delaware / U.S.A.

City Dover

Inspection Date January 30, 2020

Tank Manufacturer Unknown

Design Standard API 650 (3rd Edition assumed)

Date of Construction 1970 (per repair certification report)

Tank Contents Jet A (F-24)

Tank Serial Number unknown

Tank Diameter 100’-0”

Shell Height 40’-6”

Overflow Height 38’-3”

Tank Capacity 51,370 BBL nominal (nameplate), 53,500 BBL (to overflow), 47,000 BBL (LLA to HLA)

Foundation At grade concrete ringwall.

Construction and Material

Bottom Lap-welded carbon steel plate (5/16 per 2010 completion report).

Shell Five courses of butt-welded carbon steel plate.

Floating Roof Petrex internal Floating Pan.

Fixed Roof Lap welded steel cone roof.

Cathodic Protection Impressed Current.

Interior Coating System Epoxy 100% (assumed)

Exterior Coating System Epoxy/epoxy/polyurethane (assumed).

Level Gauging Enraf ATG and water probe, manual gauging well, Shand and Jurs autogauge (mechanical tape level gauge).

Overfill Protection Independent high and high-high level alarms, ATG (redundant) alarms, autogauge actuated alarms, float operated high level control valve.

Piping Receipt 8” Welded Carbon steel

Issue 8” Welded Carbon steel

Low Suction 4” Welded Carbon steel

Water Draw-off 1” Welded Stainless-steel

Level Alarms Shell mounted (independent) high, high-high, and low-low level alarms; ATG (redundant) alarms; autogauge actuated alarms.

C. FINDINGS AND RECOMMENDATIONS

Tank Facility 734 was found to be in generally good condition. The tank is fully serviceable, with no mandatory deficiencies that would require immediate removal of the tank from service. However, there were a few minor items observed that could be addressed to reduce long-term maintenance, improve operability, and more clearly comply with federal, state, and local regulations or military criteria.

1. MANDATORY REPAIRS per API 653, NFPA, or CFRs

Mandatory repairs represent items that require immediate attention in order to prevent imminent risk to system operators, equipment, or the adjacent environment. The tank would have to be taken out-of-service to complete these repairs. No Mandatory Repairs are required to be performed.

2. SHORT TERM RECOMMENDATIONS

REQUIRED REPAIRS to Fully Comply with API 653, UFC 3-460-01, or AW 78-24-27 Standards Short-

Term Repairs that directly relate to the long-term preservation of the asset. Short-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. These items may be required by federal, state and local codes or by military criteria.

a. Provide Scaffold Cable Supports

OBSERVATION: There are no scaffold cable supports on the fixed roof. Scaffold cable supports may be incompatible with a perimeter guardrail.

REFERENCE: Guidance for the design of new storage tanks, provided in UFC 3-460-01, Table 8-1, Item ff, and DoD Standard Design AW 78-24-27, includes scaffold cable supports on the fixed roof.

RECOMMENDATION: The next time interior tank coating work is performed, provide two scaffold cable supports on the fixed roof, if coating contractors indicate they can be used with a perimeter guardrail.

b. Provide Overflows

OBSERVATION: While the combined capacity of all of the ways the tank may receive fuel is approximately 3700 gpm, the 8-inch receipt piping may only deliver approximately 1876 gpm at a fuel velocity of 12 feet per second as prescribed by UFC 3- 460-01, paragraph 9-2.1.5. However, the tank has only two small overflows each measuring approximately 2 feet long by 3 inches high and positioned very close to the top of the shell.

REFERENCE: API 653 paragraph H.5.3.3 requires that when overflows are provided, that they be sized to discharge at the receipt rate for the tank and positioned so that an overflow will not damage the tank or roof or interrupt operation floating roof. Guidance for new construction, included in DoD Standard Design Drawing AW 78-24-27, includes overflows with a screened area measuring 1 foot by 3 feet and providing approximately two square feet of net open area per overflow. Note 12 located below the nozzle schedules in the standard design reads, “Provide at least one overflow for every 1200 gpm of receipt. Guidance for new construction, provided in UFC 3-

460-01, Table 8-1, Item l, includes high and high-high level alarms, independent from the tank gauging system, accessible from the stairway, and at 95 percent and 98 percent of level from the tank bottom to the overflow. Guidance for new construction, provided in DoD Standard Design

Drawing AW 78-24-27 and UFC 3-460-01, Table 8-1, Item bb includes a level control valve that closed between high and high-high level.

RECOMMENDATION: Provide two overflows per DoD Standard Design Drawing AW 78-24-27.

Relocate the high and high-high level alarms and the level control valve float chamber per UFC 3-

460-01.

Overflow

c. Provide Upper Shell Manhole

OBSERVATION: The is no upper shell manhole for accessing the top of the internal floating pan.

REFERENCE: Guidance for new construction, provided in DoD Standard Design AW 78-24-27 and

UFC 3-460-01 Table 8-1 item ‘c’ includes an upper shell manhole for accessing the internal floating pan at high leg position.

RECOMMENDATION: Provide an upper shell manhole.

d. Modify Stairway

OBSERVATION: There is no intermediate landing for accessing the high level alarms and level control valve float. There is also no intermediate landing for accessing an upper shell manhole if one is provided. There is also no personnel grounding device at the bottom of the stairs.

REFERENCE: Guidance for new construction, provided in DoD Standard Design AW 78-24-27, includes a circumferential stairway with a lower landing for accessing the upper shall manhole, an intermediate landing for accessing the high level alarms and the level control float chamber, and personnel grounding at the bottom of the stairs.

RECOMMENDATION: Modify the circumferential stairway to provide lower and intermediate landings for accessing the new upper shell manhole and the high level alarms and the level control float chamber. Provide personnel grounding at the bottom of the stairs.

e. Reinstall and Recalibrate Autogauge

OBSERVATION: The Shand and Jurs autogauge tape is connected directly to the floating pan per the

1993 USACE Standard Design AW 78-24-27. As a result, the gauge is broken, and the bump checker is inoperable.

REFERENCE: Guidance for new construction, provided in UFC 3-460-01, Table 8-1, Item o, and DoD

Standard Design AW 78-24-27 (2015) also, includes a mechanical tape level gauge (autogauge).

Manufacturers of mechanical tape level gauges (Varec and Shand and Jurs) recommend attaching the tape to a float in a floating pan penetration well or to a weight resting on top of the pan, but not directly to the pan to avoid damage to the tape or gauge head in the event the pan does not descend smoothly with the fuel, which is a consistent problem with smaller tanks. UFC 3-460-03 Section 8-

9.8.1.1 requires mechanically operated tape gauges to be checked regularly in order to verify accuracy. If the tape is not accurate, UFC 3-460-03 requires calibration.

RECOMMENDATION: Reinstall the autogauge by attaching the tape to an 8-pound weight resting on top of the pan in accordance with manufacturer’s recommendations, repair the autogauge, and calibrate the autogauge against the Enraf ATG and manual gauging. Restore operation of the bump checker. chamber. Provide personnel grounding at the bottom of the stairs.

f. Replace Vent Screens

OBSERVATION: The 24 shell vents and the roof center vent are covered with vents with 1/4-inch holes. Holes smaller than 1/2-inch significantly reduces the ventilation capacity and is subject to clogging and freezing over.

REFERENCE: API 650 paragraph H-5.2.2 requires vent screens with 1/2-inch openings.

RECOMMENDATION: Replace the screens on the 24 shell vents and the roof center vent with screen having 1/2-inch openings.

Stairway top Platform

Peripheral Vent

Roof Center Vent Screen

g. Replace Level Control Valve

OBSERVATION: The nearest isolation valve upstream of the level control valve is approximately 15 feet from the level control valve. The level control valve is made of aluminum.

REFERENCE: UFC 3-460-01 paragraph 12-9 and DoD Standard Design AW 78-24-27 also include an isolation valve near to and upstream of the level control valve for maintenance of the level control valve. NFPA 30 paragraph 27.4.3 and UFC 3-460-01 paragraph 3-6.7.1 prohibit valves made of aluminum and other low melting point materials. Guidance for construction of fuel system piping provided in UFC 3-460-01 paragraph 15-11.5 includes diaphragm control valves made of stainless-steel or internally chrome plated steel or internally nickel-plated nodular iron and prohibits aluminum valves. Guidance for new construction provided in DoD Standard Design AW 78-24-27 includes a pipe support that is mounted on an extension of the tank foundation and located between the level control valve and an upstream isolation valve, which works with the ball joints to eliminate stress on the tank shell.

RECOMMENDATION: Relocate the upstream isolation valve adjacent to and upstream of the level control valve. Replace the aluminum level control valve with a stainless-steel or internally chrome plated steel or internally nickel-plated nodular iron level control valve.

Control Valve

Isolation Valve

h. Provide OSHA Compliant Internal Ladder Access Hatch

OBSERVATION: The 36-inch internal ladder access manhole provides approximately only 28 inches of clearance on the climbing side of the ladder. The cover is not bolted and does not have a rain lip.

A small pool of water was noted on the internal floating pan under the ladder access manhole.

REFERENCE: OSHA regulation 29 CFR 1910.23 (d) (June 2018) requires 30 inches of clearance (24 inches with a deflector plate) on the climbing side of a ladder including at access hatches. Guidance for new construction, provided in DoD Standard Design AW 78-24-27, includes an OSHA compliant internal ladder access hatch with a rain lip.

RECOMMENDATION: Provide an OSHA compliant internal ladder access opening and a hatch with a rain lip.

i. Provide a Grounding System for the Product Saver Tank

OBSERVATION: The product saver tank stainless-steel piping and is not connected to but isolated from the tank by isolation flange kits on the shell nozzle isolation valves. An electric motor is mounted on the side of the product saver tank, but the tank is not grounded.

REFERENCE: Guidance, provided in DoD Standard Design AW 78-24-27 and UFC 3-460-01 paragraph 2-12.3, include grounding for new product saver tanks. Paragraph 9-8. i), includes isolation flanges for connecting dissimilar metals.

RECOMMENDATION: Provide a grounding system for the product saver tank, and not the same grounding system as that on the tank in order to maintain electrical isolation. Provide isolation flange kits on the shell nozzle isolation valves between the carbon steel and the stainless-steel.

j. Provide a Product Return Nozzle

OBSERVATION: The product saver tank product return is the same nozzle as the water draw-off.

REFERENCE: Guidance, provided in DoD Standard Design AW 78-24-27 includes a dedicated product return nozzle, stainless-steel piping and an isolation valve, with an isolation flange kit on the shell nozzle to connect the product return to the product saver tank to more efficiently remove water from the tank.

RECOMMENDATION: Provide a dedicated product return nozzle, stainless-steel piping and an isolation valve, with an isolation flange kit on the shell nozzle.

k. Demolish High Point Vents

OBSERVATION: As shown in the photographs below, which are borrowed from the 2013 Piping

Integrity Management Plan, the receipt and issue nozzles are fitted with high point vents and ball valves. Depending on the slop of the piping, the tank may act as a high point vent or a low point drain. The high point vents are redundant to the tank, are a source of potential leaks, and unnecessarily drain maintenance resources.

REFERENCE: Guidance, provided in DoD Standard Design AW 78-24-27 does not include highpoint vents or low point drains at tanks, but does include sloping the piping to drain toward the tank.

RECOMMENDATION: Demolish the high point vents on the receipt and issue nozzles.

l. Replace Thermal Relief Valves and Piping

OBSERVATION: The receipt piping thermal relief valve data plate indicates a set pressure of 75 psig, which may allow slight and unintentional filling of the tank if the valve is closed when the receipt piping is pressurized and may result in premature failure of the receipt thermal relief valve due to wash out of the internal seats. The receipt thermal relief and low suction thermal relief piping includes sight flow indicators and do not include testing tees. Sections of the thermal relief piping and some of the valves are stainless-steel, with no isolation flanges between the carbon steel and the stainless-steel piping.

REFERENCE: Guidance for new construction, provided in UFC 3-460-01 paragraph 9-3.5, includes thermal relief valves on piping sections that have the potential to be isolated by a shut-off valve.

Paragraph 9-3.5.1 recommends a set pressure of 10 percent above pump deadhead and prohibit installing sight flow indicators on new thermal relief piping. DoD Standard Design AW 78-24-27 testing tees for new thermal relief piping. Guidance for new construction, provided in DoD

Standard Design AW 78-24-27 includes stainless-steel thermal relief piping and vales at storage tanks. Guidance for new construction, provided in UFC 3-460-01 and DoD Standard Design AW 78-

24-27 includes isolation Guidance for new construction provided in DoD Standard Design AW 78-

24-27 and UFC 3-460-01 paragraph 2-12.3 includes isolation flanges for connecting dissimilar metals.

RECOMMENDATION: Replace the thermal relief valves and piping around the receipt, issue, and low suction nozzle isolation valves with valves and piping that comply with UFC 3-460-01 and DoD standard design AW 78-24-27.

3. LONG-TERM RECOMMENDATIONS

RECOMMENDED REPAIRS as Part of Regular Maintenance Long-term Repairs that directly 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.

a. Replace Dike Liner

OBSERVATION: There are numerous holes and patches in the dike liner. The dike liner fabric is exposed in many places. The liner has reached the end of its useful life.

REFERENCE: NFPA 30 paragraph 22.11.2.4 and 40 CFR 112.7(c)(1) require secondary containment to be liquid tight.

RECOMMENDATION: Replace the dike liner. Replace the sealant between the dike access steps and the concrete covered dike berms or consider replacing the dike access steps and attaching the new liner to the new concrete dike access steps.

b. Repair and Seal Concrete Skirt to Foundation

OBSERVATION: The foundation ringwall to dike basin seal has failed. The dike liner is attached to the concrete dike basin at the ringwall. A 1 to 2-inch wide strip of the dike basin is exposed all around the ringwall and is broken up on northwest side.

REFERENCE: NFPA 30-22.11.2.4 and 40 CFR 112.7(c)(1) require liquid tight secondary containment.

RECOMMENDATION: Replace the dike basin concrete adjacent to the ringwall where it is broken up.

Replace the sealant between the dike basin concrete and the tank foundation ringwall or consider attaching the new liner to the dead shell (tank shell below the second bottom).

c. Replace the First (original tank bottom)-to-Foundation Seal

OBSERVATION: The ringwall height varies from zero to 2 inches above the dike basin. The exposed surface of the ringwall is limited to a 1-inch wide strip (measured radially) and is eroded away, exposing the aggregate. There are holes in the first (original) bottom-to-foundation seal on the west side. Moss is growing out from under the bottom-to-foundation seal on east side.

REFERENCE: NFPA 30 paragraph 22.11.2.4 and 40 CFR 112.7(c)(1) require secondary containment to be liquid tight. Guidance for new construction, provided in DoD Standard Design AW 78-24-27 and UFGS Specification 33 56.13.13, include installation of the tank bottom-to-foundation seal to be performed by a coating contractor.

RECOMMENDATION: Coat the underside perimeter of the first (original tank bottom). Seal coat the foundation and replace the tank bottom-to-foundation perimeter seal. Consider attaching the new liner to the dead shell (tank shell below the second bottom) an alternative to the above repairs.

d. Repair Coating

OBSERVATION: There is a considerable amount of bird droppings on the roof and roof guardrails, which could result in deterioration. There is also corrosion on the internal floating pan installation hatch and where a conduit support channel for the water probe is broken loose from the glue. The mating surfaces of the flange and cover of the 36-inch round internal ladder access roof hatch are corroded. The drilled blind flange on top of the water probe well is uncoated carbon steel and is corroded.

REFERENCE: Guidance for new construction, provided in UFC 3-460-01 paragraph 8-3.10, includes coating the exterior. UFC 3-460-03, Appendix F (Monthly Tank Inspection Checklists) requires base personnel to inspect for evidence of corrosion. API 571 paragraph 4.3.2.3.h) reads, “bird turds can also cause accelerated corrosion and unsightly stains.”

RECOMMENDATION: Add regular power washing of the exterior of the roof and lower shell to the regular maintenance schedule. Power wash the exterior of the roof. Provide spot repairs to the coatings on the roof, roof manhole flange and cover, internal floating pan installation hatch, and water probe well blind flange (approximately 25 square feet).

e. Replace ATG Flange Bolting

OBSERVATION: The Enraf ATG flange bolting is corroded.

REFERENCE: Paragraph 9-8. f), includes stainless-steel bolts on stainless-steel flanges, and on carbon steel flanges in corrosive environments.

RECOMMENDATION: Replace the ATG flange bolting with stainless-steel.

f. Demolish Abandoned Conduit Support Channel

OBSERVATION: There are abandoned conduit support channel welded to the shell. Abandoned appurtenances may be a source of deterioration.

REFERENCE: NA

RECOMMENDATION: Demolish the abandoned conduit support channel from the shell.

g. Modify Secondary Containment

OBSERVATION: The secondary containment liner covered basin is sloped toward the tank and piping on the southside to a dike drain sump located on the northside.

REFERENCE: NFPA 30 requires secondary containment to be sloped away from the tank for 50 feet or to the dike wall, whichever is less, and away from product piping for a distance of 50 feet.

RECOMMENDATION: Modify the secondary containment to slope way from the tank and the piping per NFPA 30.

Slope

Dike Drain

Piping

Slope

APPENDIX ‘A’: ENGINEERING CALCULATIONS AND DRAWINGS

SHELL THICKNESS CALCULATIONS

Job No.: 19-091.03

Job Title: SPCC Tank Inspections - Dover AFB

Subject: Tank Facility 734

By: Mike O'Connor Date: 3/6/20

API-12C

API 653

SHELL CALCULATIONS

Diameter 100 feet Shell Height 40.50 feet Freeboard 2.25 feet Design Fill Height 38.25 feet Specific Gravity 0.84 API 650

0.84 API 653

Joint Efficiency 1.00 API 650 Material Unknown Yield Strength 30,000 psi (assumed) Tensile Strength 55,000 psi (assumed)

Original Design Corrosion Allowance

0.062 in

Required thickness Lower Upper

Two CoursesCourses

Allowable Stress 23595 25960

Height Product Required Thickness Course (feet) Depth 1/4" min

5 8.44 6.17

4 8.17 14.33

3 8.17 22.50

2 8.17 30.67

1 7.58 38.25 min 2020 Corrosion Estimated UTM Visual current net 1970 Rate Service Life Inspection Inspection Course UTM* thick Thickness * in/yr yrs. Interval Interval

5 0.255 0.255 0.256 0.000 >30 15 5

4 0.261 0.261 0.264 0.000 >30 15 5

3 0.329 0.329 0.342 0.000 >30 15 5

2 0.446 0.446 0.447 0.000 >30 15 5

1 0.569 0.569 0.579 0.000 >30 15 5

* The original thicknesses are assumed based on required design thicknessess, overtolerance and the range of the UTMs.

P.O. Box 4800 4800 W. Hundred Road Chester, Virginia 23831 Phone: 804-748-8746 Fax: 804-748-7849 www.brockenbrough.com

0.345

0.275

2.6(H-1)DG

0.248

0.118

0.343

0.430

0.297

0.208

0.100

0.469

0.386

0.060

0.154

API-653

Original Design

0.112

0.181

2.6HDG

SESESE

(psi) 2.6(H-1)D

API-650

Original Hydro 2250020000

SHELL AND ROOF ULTRASONIC THICKNESS MEASUREMENTS

Job No.: 19-091.03

Job Title: SPCC Tank Inspections - Dover AFB

Subject: Tank Facility 734

By: Mike O'Connor Date: 3/6/20

SHELL UTM DATA (0.001 inches)

1 3

2 4 Typical Shell Plate UTMs.

1 2 3 4 average 1-1a 569 579 1-2 582

1-4c 581 1-6 585

UTMs Taken From Stairway

1-1 average (assumed original) 2-3 449 446 446 447 average (assumed original) 3-3 329 330 367 342 average (assumed original) 4-1 266 265 261 264 average (assumed original) 5-1 255 256 257 256

Roof UTMs

253 230 225 202 195 260 194 197 190 199 188 204 251 229 233 198

P.O. Box 4800 4800 W. Hundred Road Chester, Virginia 23831 Phone: 804-748-8746 Fax: 804-748-7849 www.brockenbrough.com

SHELL SETTLEMENT ANALYSIS

Austin Brockenbrough & Associates, L.L.P. Job No. 19-091.03

Location: Dover AFB Date: 3/11/2020

Subject: Tank 734 - Shell Settlement Evaluation By: Mike O'Connor

API 653 Appendix B

Optimum cosine curve, B 2.2.4.e) Z = a + b x cos(theta + c)

Diameter (D) = 100 (ft)

Number of equally spaced data points (ft)= 10

L = Arc length between measurement points (ft) = 31.42

Tank Height (H) = 38.3 (ft)

Relative elevation of lowest horizontal weld seam (ft).

* Z U S

0 2.41 0.00 0.00 0.00 0.01

1 2.42 0.01 0.01 0.00 -0.01

2 2.42 0.01 0.01 0.01 0.00

3 2.41 0.00 0.03 0.03 0.02

4 2.44 0.03 0.03 0.01 0.00

5 2.46 0.05 0.04 -0.01 -0.01

6 2.46 0.05 0.03 -0.01 0.00

7 2.44 0.03 0.03 0.00 0.00

8 2.43 0.02 0.01 -0.01 0.01

9 2.43 0.02 0.01 -0.01 -0.01

10 2.41 0.00 0.00 0.00 0.01

Maximum out-of-plane deflection = 0.02

* = measured elevation

*HI (Height of Instrument)

Z = calculated ridged body tilt (in)

U = out-of-plane settlement =

S = out-of-plane deflection z-y

Y = yield sterength of shell material (PSI) = 30,000 (unknown 1970s steel)

E = Youngs modulas of elasticity (lbf/in2) = 29*10^6

S allowable (in) (API 653 B.3.2.1) = (L^2*Y*11)/(2EH)*12 = 0.15 ft

R^2 = (Syy - SSE) / Syy = 0.46 not >=0.9 therefore cosine curve is invalid.

Evaluation by the Arc Length Method described in API 653 B.2.2.5.1 is required.

Austin Brockenbrough & Associates, L.L.P. Job No. 19-091.03

Location: Dover AFB Date: 3/11/2020

Subject: Tank 734 - Shell Settlement Evaluation By: Mike O'Connor

API 653 B.2.2.5.1 Evaluation by Settlement Arc Length Method

* Open top (yes/no) = no Per B.3.2.2, K = 3.9

Settlement arc length (ft), Sarc

Out of plate settlement at Point i (Si)

Allowable settlement at point i (Smax) = MIN[K*Sarc*(D/H)*(Y/E), 4]

Point Sarc (ft) Si (ft) Smax (ft)

0 62.8 0.02 0.06 OK

3 125.7 0.03 0.11 OK

7 94.2 0.01 0.08 OK

* For the purpose of this evaluation tanks with geodesic domes and barn roofs are consided to be open top, as those types of roofs do not significantly restrain shell deformation.

Evaluation of the settlement by the arc length method indicates the settlement is within acceptable limits.

Si < Smax →

Si < Smax →

Si < Smax →

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0 2 4 6 8 10 12

Measured Elevation (in)

Si7 Si3 Si0

TANK DRAWINGS

OSHA ACCESS STRUCTURE REPORT

OSHA Circumferential Stairway Data

OSHA Rq’d Actual

(in) min (in) max (in)

Handrail Height 32 OK 30 34 Step Width 24 OK 22 NA

Step Rise 8 OK 7 9 Bottom Step Rise 8 OK 7 9

BOTTOM STEP

RISE

APPENDIX ‘B’: API 653 CHECKLISTS FOR TANK INSPECTIONS

UL SWRI

API Other

Protected

53,500 BBL (to overflow)

Type: Type:

Size: Date Installed:

stainless steel End Conn: Size: 8" Material: stainless steel End Conn: Size: 12"

Issue To:

Release Prevention Barrier

Overfill Protection / Level Alarms:

Independent L, H, and HH and ATG Alarms Level alarms and 8" level control valve

Receipt Piping Configuration Issue Piping Configuration

Tank Piping

Secondary Containment

In-service, Oct 2015

Tank Specifications

Previous Tank Inspection Date:

Continuous Release Detection Monitoring

Type:

Date Installed:

Current Product:

100'-0" dia by 40'-6" tall

NA

Nominal Capacity:

Inspector Certification Number:

Overfill Protection:

Monitoring well

Useable Capacity:

Tank Construction and Configuration

Insulated

Coated

Plastic / Fiberglass

Other:

welded hydrant system tanks

Liner (assumed)

47,000 BBL (LLA to HLA)

API 653 EXTERNAL INSPECTION CHECKLIST

POL AreaProject Site:Project Name:

Project Location:

Brockenbrough Job No.:

SPCC AST Inspections

Dover AFB

General Inspection Information

19-091.03

Submitted to:

Contract No.:

USACE Omaha

W9128F-17-D-0017

Tank Facility No.:

Local Tank ID No.:

January 30, 2019

Tank Manufacturer:

Tank Construction Date:

Tank 734 Mike O'Connor

Vertical

Rectangular

Double Wall

Fire Resistant

Closed Top Dike

Change of Service:

Last Repair:

Tank Coatings:

Exterior Coating:

epoxy-polyurethane (assumed)

100% - epoxy (assumed)

Jet-A

51,370 BBL (repair plate)

Horizontal Single Wall

Open Type Dike

Tank Inspector Name:

2010 (second bottom, shell manholes, honeycomb-IFR, L, H and HH alarms, and more)

Inspection Date:

Design Std

Tank Outside Dimensions:

Secondary Containment, Overfill, and CRDM

Interior Coating:

Double Bottom

Unknown

Liner over concrete berms

63" by 283' by 328'

Level Alarms:

Material: welded

Receipt From: commercial pipeline

API 653 EXTERNAL INSPECTION CHECKLIST

POL AreaProject Site:Project Name: SPCC AST Inspections

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A Sloped toward tank on southwest.

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Check for:

STATUS

a) b)

COMMENTS

c)

TASK

Check for:

Tank Settlement

Review cathodic protection potential readings

Check for :

C.1.1.4 Rock

Measure foundation levelness and bottom elevations (See Annex B)

C.1.1.1 Concrete Ring

Cavities under foundation;

vegetation against bottom of tank

Broken concrete, spalling, and cracks, especially under backup bars used in welding butt-welded annular rings under the shell

Indications of bottom leakage at drain openings in ring, back of water-draw basins, and top surface of ring

Run-off rainwater from shell draining away from the tank

Ringwall height varies from o" to 2" above the dike basin. Exposed surface of ringwall is limited to a 1" wide strip (measured radially) and is eroded away, exposing the aggregate.

d) a)

C.1.1.3 Oiled Dirt or Sand

7V, 2A b)

Settlements into the base

C.1.1.2 Asphalt

Leaching of oil which has left rock filler exposed indicating hydrocarbon leakage

Tank settlement into asphalt base

C.1.1.7 Cathodic Protection

ITEM

C.1.1 Foundation

Sloped toward tank on southwest.

a) b)

C.1.1.6 Housekeeping

Build-up of trash, vegetation, and other inflammables

e) Settlement around perimeter of tank

C.1.1.5 Site Drainage

Check for:

Proper operation of dike drains

Site drainage away from the tank, associated piping, and manifolds

Check for:

Check for:

Presence of crushed rock under the steel bottom which usually results in severe underside corrosion.

C.1.2.1 External Visual Inspection

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

C.1.2.3 Riveted Shell Inspection

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Holes in bottom to foundation seal on west side. Moss growing out from under seal on east side.

C.1.2.4 Wind Girder (Floating

Roof Tanks) a)

Rivet and seam leaks on external surface

Check for:

Corrosion and thinning on plate and weld after cleaning the bottom angle area

Paint failures, pitting, and corrosion

Full fillet lap-welded vertical seams to increase joint efficiency b) c)

Check for:

Grooving, corrosion, pitting, and coating failures a) b)

c) Bottom-to-Foundation Seal

e) Drawings of riveted seams if available. Otherwise, dimension and sketch (or photograph) the rivet pattern: no. of rows, rivet size, pitch length, butt-riveted or lap-riveted joints a) c)

Broken welds and corrosion damage

(paint failure, pitting, corrosion, product build-up), especially where it occurs at tack-welded junction d)

Check for:

Pitting on support welds to shell, especially on shell plates b)

Corrosion loss and wear on the rivets

Reinforcing pads welded to shell at supports

Leaks and identify the location by sketch or photo

C.1.2. Shells

Check for:

C.1.2.2 Internal (Floating Roof

Tank)

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Check for:

COMMENTSITEM TASK

b)

Cracks or signs of leakage on weld joint at nozzles, manholes, and reinforcing plates

C.1.3.2 Tank Piping Manifolds

Flange leaks and leaks around bolting

Shell plate dimpling around nozzles, caused by excessive pipe deflection c)

Damage on welds on shell-mounted davit clips above valves 6 inches and larger g)

Anchored piping which would be hazardous to the tank shell or bottom connections during earth movement

Adequate thermal pressure relief of piping to the tank

Proper operation of regulators for tanks with purge gas systems

Leaks at sample connections and proper valve operation

Damage and test the accuracy of temperature indicators h)

Sealing of insulation around manholes and nozzles

e) Adequate manholes flange and cover thickness on mixer manholes

Receipt TRV set at 75 psi. TRV piping and flanges corroded. Issue TRV piping is a mixiture of CS and SS with no isolation.

a) Leaks on autogauge tape guide and lower sheave housing (floating swings)

b) Damage on autogauge head

Fire fighting system componentsb) c) d) d)

Check for:

e) f)

a) Leaks at piping manifolds, flanges, and valves

Check for:C.1.3.3 Autogauge System a)

C.1.3.1 Manholes and Nozzles

C.1.3 Shell Appurtenances

STATUS

Pass Fail N/A Bump checker inoperable.

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

c) Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Autogauge inoperable.

C.1.3.3 Autogauge System c) d)

C.1.3.4 Shell-mounted Sample

Station a) a) b)

Proper mounting flange and support

Leakage

COMMENTS

h) Condition of board and legibility of board-type autogauges

Freedom of movement of marker and float b)

Check for:

Function of valves and plugging in sample lines, including drain or return-to-tank line

Leaks in circulation pump and operating problems

Inspect condensate drain for presence of oil indicating leakage C.1.3.5 Heater (Shell Manhole

Mounted)

C.1.3.6 Mixer Check for:

c) Condition of power lines and connections to mixer

Bracing and supports for sample lines and equipment i) e) f) g)

Proper movement of tape by bumping the checker on autogauge head

Size and construction material of the autogauge tape guide and make note (floating roof tanks)

Proper movement of tape. Ask the operator if the tape tends to hang up during tank roof movement (floating roof tanks).

Actual product level compared to the reading on the autogauge. Make note. (max. variation is 2 in.)

No more than 2 feet of tape are exposed at the end of the tape guide when the roof is in lowest position

(floating roof tanks)

ITEM TASK STATUS

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

b) Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Floating: With tank half full or more, lower the swing line, then let out the cable and check if the swing has pulled cable tight, indicating that the winch is operating properly

ITEM TASK

C.1.3.7 Swing Lines: Winch a)

Operation

Indicator: Check that the indicator moves in the proper direction.

Floating swing line indicators show a lower level as cable is wound up on the winch. Non-floating swing line indicators show the opposite b) c)

Target should indicate direction of swing opening (up or down) and height above bottom where suction will be lost with swing on bottom support

COMMENTSSTATUS

C.1.3.12 Swing Lines: Target

Non-floating: Raise, then lower the swing line with the winch and check for cable lightness to confirm the swing line lowered properly

C.1.3.8 Swing Lines: External

Guide System

Check for leaks at threaded and flanged joints

C.1.3.9 Swing Lines: Identify

Ballast Varying Need

Check for significant difference in stock specific gravity

Check for:C.1.3.10 Swing Lines: Cable

Material and Condition a) Corrosion over entire length, for non-stainless steel cable

Wear or fraying on all types of cable

C.1.3.11 Swing Lines: Product

Sample Comparison

Check for water or gravity differences that would indicate a leaking swing joint

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A

Pass Fail N/A No detectable odor at 24 def F in high wind.

ITEM TASK

C.1.4.4 Level of Floating Roof At several locations, measure distance from roof rim to a horizontal weld seam above the roof. A variance in the readings indicates a nonlevel roof with possible shell out-of-round, out-of-plumb, leaking pontoons, or hang-up. On small diameter tanks, an unlevel condition can indicate unequal loading at that level.

C.1.4.5 Gas Test Internal Floating

Roof

Test for explosive gas on top of the internal floating roof, Readings could indicate a leaking roof, leaking seal system, or inadequate ventilation of the area above the internal floating roof.

C.1.4 Roofs

Bird droppings on roof and guardrails. Corrosion on pan installation hatch. Corrosion where conduit support channel is broken loose from glue.

C.1.4.1 Deck Plate Internal

Corrosion

COMMENTS

C.1.4.2 Deck Plate External

Corrosion

STATUS

Visually inspect for…