Above Ground Storage Tank
Design, Inspection, and Compliance
Management
By Gregory Coppola, P.E.
Kinder Morgan Energy Partners,
L.P.
Introduction
• Kinder Morgan Overview
– Midstream Energy Company
– 900+ Storage Tanks in Pacific Region
– Critical Infrastructure for Fuel Distribution
Completed New Tanks
El Paso, TX
Organization of the Presentation
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Objective of the Presentation
API Recommended Practice
Tank Construction and Tank Components
Out-of-Service Inspections
Regulatory Framework
– SPCC Rule
– APSA
– DOT Regulations
– Air Regulations – Federal and Local
Objective of the Presentation
• Provide CUPA members with an overview
of petroleum storage tanks.
• Provide an introduction to applicable
regulations.
• Assist with CUPA regulation under
Assembly Bill 1130, The Aboveground
Petroleum Storage Act.
Aboveground Petroleum Storage Act (APSA),
Assembly Bill 1130
Effective January 1, 2008
• Transfers the responsibility for the
implementation, enforcement and administration
of the Aboveground Petroleum ACT (APSA)
from the State Water Resources Control Board
(SWRCB) to the CUPA’s.
• California Health and Safety Code Chapter 6.67,
Sections 25270 – 25270.13 are also known as
the APSA.
• APSA will be discussed in more detail later in
the presentation.
API Recommended Practices
API Recommended Practices
API 650
• API 650 – Design Standard for welded
steel tanks for oil and fuel storage.
• Typically used for large field fabricated
storage tanks operating at low pressures
or atmospheric pressures.
• The standard covers materials of
construction, design, fabrication/erection,
construction inspection, and welding
procedures.
API 650
Welded Tanks for Oil Storage
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Scope
Reference
Definitions
Materials
Design
Fabrication
Erection
• Methods of Inspection
• Welding Procedures
• Marking
Tank Schematics
• The following schematics show the various
appurtenances for:
– Cone Roof Tanks
– Internal Floating Roof (IFR) Tank with Top
Foam Injection and Vapor Recovery
– Cable Suspended IFR
– External Floating Roof (EFR)
– EFR with Dome
Cone Roof Tank
IFR Tank w/Top Foam and Vapor Recovery
Cable Suspended Internal Floating Roof
External Floating Roof Tank
EFR Tank with Aluminum Dome
Tank Foundations
• Foundation Types
– Earth Foundations
– Gravel/Asphalt Surface
– Ring Walls
– Slab
– Piles with Ring or Slab Caps
Tank Foundations (Con’t)
• Design Concepts
– Vertical Loading
• Liquid pressures
• Shell and roof loads
– Overturning
• Wind
• Seismic
– Foundation Settlement
Liner Installation
Foundation Rebar
Concrete Tank Foundation
Tank Bottoms
• Constructed of overlapping steel plates.
• Plates joined by manual or automatic arc
welding techniques.
• Tank bottom to shell welds undergo the
most stress and are considered critical
welds.
Tank Bottom – In Progress
View of Tank Bottom Beneath IFR Includes Center
Column, Roof Legs, and Reinforcing Pads
Tank Double Bottoms
• Typical components (starting from below)
– Lower tank bottom
– HDPE liner
– Sand or concrete with drainage system
– Upper tank bottom
Shell Design
• Tank shells are constructed from courses
of steel plates.
• The designer will calculate a steel
thickness for each course.
• The bottom courses are thicker steel due
to hydrostatic pressure.
• Shell design criteria include hydrostatics
and wind buckling.
• Thickness includes corrosion allowance.
Construction of First Course –
Crane Inside
Construction of First Course
Hanging Plate for 4th Shell Course
Nozzles and Penetrations
• Openings in the shell result in higher
stress.
• Repads or thickened inserts may be
required.
• Stress relieving may be required.
Manway with Davit Arm
Fixed Roof Types
• Self-supported
– Cones
– Domes and Umbrellas with stiffeners
• Supported Cone Roofs
– Columns are inside tank
• Aluminum Geodesic Domes
Roof Construction – Bull Wheel
and Center Column
Roof Rafter Construction
Lifting Cone Roof
Center Column Support
Supported Roof, Partially Completed
Aluminum Dome, Lifting on to EFR Tank
Frangible Roof Joints
• Roof to shell junction designed to fail first
in an emergency.
• Future piping and maintenance must not
interfere with the functioning of the
frangible roof joint.
Fixed Roof – 24” Mushroom Circulation Vent,
Sample Vent and Skid-Proof Surface Coating
Floating Roofs, Objectives
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Reduces air emissions
Prevents product loss
Meets regulatory requirements
Improves fire safety
Floating Roofs
• Material of Construction: Steel or
Aluminum
• Roof Types
– Floating pan
– Bulkhead
– Internal pontoon
– Double deck
– Honeycomb or Foam Core
– Cable suspended Aluminum
IFR Pontoon Construction
Floating Roof Support Leg and Sleeve
(High Leg Position)
Reinforcing Pad for Roof Leg
Floating Roof Seals
• Primary Seals
– Liquid mounted foam logs
– Liquid mounted shoe seals
– Vapor mounted foam logs
– Vapor Mounted wipers
• Secondary Seals
– Elastomeric wipers
– Metallic wipers
Mechanical Primary Shoe Seal in IFR
Compression Plate Secondary Seal
with Wiper Tip on EFR Tank
Other Tank Appurtenances
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Spiral stairway
Ladders
Level gauges
Pressure vacuum vents
Shell and roof manways
Inlet diffusers
Drain sumps
Roof drain hoses
Spiral Stairway Leading up the
Tank Exterior
Internal Ladders with 8-inch Slotted
Gauge Pole
Level Gauging Systems
• Mechanical level gauging systems are
frequently used. There are multiple alarm
levels.
• Radar gauges can be mounted at the fixed
roof or in a gauge well.
• The gauging system often ties into the
overall facility SCADA system.
• A redundant alarm is recommended by
API.
Level Gauging System
Mounted on Tank Exterior
Sample Hatch
Top View of IFR
Two 12” Pressure Vacuum Vents and Center
Column
Drip Tray for Center Column with
Hold Down Chains
Ladder Well Drip Tray
and Chained Slide Plate
Tank Bottom Sump
Newly Painted
Ladder, Slotted Gauge Pole, and Sump
Slotted Inlet Diffuser
Slotted pipe
Inlet Diffuser -- Hole Type
Suction Line Trough
Water Draw Piping
Coiled Roof Drain Hose
Beneath Internal Floating Roof
Reinstalling a Door Sheet
at the Conclusion of the Project
Fire Systems
• Refer to NFPA 11 – Standard for Low-,
Medium-, and High-Expansion Foam.
• The Standard contains design criteria for
hydrocarbon storage tanks.
• The criteria include:
– Application rate
– Discharge time
– Minimum number of outlets
Fire Systems (Con’t)
• Fixed roof tanks may be designed with
subsurface injections.
• Floating roof tanks will be designed with
over-the-top injection.
• Foam dams are used to focus on fighting
seal area fires.
• Other fire systems are designed for “Full
Surface Fires.”
Foam Fire Systems
Foam Chamber Installed in Tank
Shell
Tank Cathodic Protection
• Galvanic Corrosion
– Can occur on the underside of a tank bottom
causing oxidation, general corrosion, and
pitting.
– Galvanic cell requires:
• Anode – active metal at the tank bottom.
• Cathode – less active metal in the vicinity of the
tank.
• Electrical path – tank bottom and soil.
• Electrolyte.
Tank Cathodic Protection (Con’t)
• Impressed Current Systems
– Includes a DC current source created by a
rectifier and a buried impressed current
anode.
– Creates a current to counteract the galvanic
cell and forces current to the tank bottom to
prevent oxidation (loss of electrons).
• Sacrificial Anode
– The anode losses electrons rather than the
tank.
Impressed Current Corrosion
Protection
API Recommended Practices
API 653
• API 653 – Tank Inspection, Repair,
Alteration and Reconstruction.
• Tanks are inspected to determine their
suitability for service.
• The standard includes recommendations
for tank inspection interval.
• This standard governs out of service
inspection and repair work.
API 653
Tank Inspection, Repair, Alteration and
Reconstruction
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Scope
Reference
Definitions
Suitability for Service
Brittle Fracture
Inspection
Materials
Design Considerations
• Tank Repair and
Alterations
• Dismantling/Reconstr
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• Welding
• Examination Testing
• Marking
Other API Methods Relevant to Tanks
• API 651 – Cathodic Protection for Storage
Tanks.
• API 652 – Linings for Storage Tanks.
Standard for Internal Coating.
• API 2000 – Venting for Atmospheric and
Low Pressure Tanks.
• API 2350 – Overfill Protection for Storage
Tanks.
API Recommended Inspection
Schedule
• Routine In-Service Visual Inspection
– Frequency not to exceed one month.
– Can be performed by Owner/Operator
personnel.
• External In-Service Inspection
– Visual inspection of the tank exterior .
– By Authorized Inspector (API 653 Certified).
– Frequency not to exceed 5 years, but may be
more frequent based on corrosion calculation.
API Recommended Inspection
Schedule
• Ultrasonic Inspection
– Ultrasonic measurement of tank shell.
– Inspections at 15 year intervals or possibly
more frequent based on shell corrosion
calculation.
– Initial inspection in 5 years to establish a
corrosion rate.
– Corrosion rate may be estimated from tanks
in similar service.
API Recommended Inspection
Schedule (Con’t)
• Internal Inspection
– Inspections at 20 year intervals or possibly
more frequent based on tank bottom
corrosion calculation.
– Initial inspection in 10 years to establish a
corrosion rate.
– Corrosion rate may be estimated from tanks
in similar service.
Tank Maintenance Projects
Typical Tasks
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Empty tank.
Isolate.
Clean and degas.
Inspection blast of floor coating.
API 653 inspection.
Issue preliminary inspection report and
develop list of maintenance/repair items.
• Perform tank maintenance and repair
work.
Tank Maintenance Projects
Typical Tasks (Con’t)
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Tank strapping
Final blast
Tank coating
Final inspection
Return tank to service
Exterior painting or concrete/asphalt work
(optional)
• Final construction documentation
Safe Work Practices
• Safety is Everyone’s Job
• Learn to Recognize Safe Work Practices
Safe Work Permitting Procedure
Heavy Tools are Lifted by Rope
Tag Line not Hand Carried
Confined Space Vapor Monitoring
Radio Communication
Leg Setting
• The tank contractor will set the IFR legs
from high position to low position to land
the roof.
• This requires a confined space entry from
the manway on the fixed roof.
Use Body Harness and Tripod for
Confined Space Entry
Tripods Must Have Leg Chains for Stability
Pulley Must be Mounted and Secure
Body Harness Must Be Properly Attached
Lock Out / Tag Out
• Lock out, tag out procedures are followed for
piping and electrical.
• Contractors verify that all valves have been
closed and locked out.
• Ensure that the terminal piping has been
totally isolated (review terminal piping
drawings).
Plan Lockout/Tagout
Gauge the Tank to Check that it is
Empty
Close, Lock, and Tag Valves to
Isolate
Electrical Lockout/Tagout
Tank Valve Lockout
Document the Valve Positions
Tank Isolation
• For all lines, a valve is removed and blinded to
create an air gap.
• Metal drip pans and vacuum truck are required
when isolating the tank.
• Bonding cables are required when removing
valves.
• 150 lb. blind flanges and new gaskets are
required.
• After blinding has been completed, the piping is
visually inspected to ensure tightness.
Inspecting Empty Vacuum Truck Prior to
Use
Bonding Cables and Metal Drip Pan
Valve removal including bonding cables,
respirators, gloves, fire extinguisher, metal
drip pans and vacuum truck hose.
Isolated Tank Valve with Air Gap
Isolated Buried Line with Barricades
Tank Degassing
• Tank degassing is performed, when required,
based on product type and location in
accordance with EPA, State, or local air
regulations.
• Portable Thermal Oxidizers are most frequently
used to handle the combustion throughput. IC
engines or activated carbon systems can be
used.
• The units need to have the appropriate air
permit and operate in accordance with the
permits.
Portable Thermal Oxidizer and Generator
Degassing Unit Placed Outside of Tank
Berm
IC Engine Degassing Unit
Temperature and Flow Monitoring is
Typically Required by the Air Permit
Once the Manway is Removed Plastic
Sheeting is Place over it Immediately
The Vapor Hose Penetrates the Plastic
Sheeting
Tank Cleaning
• Proper placement of equipment to separate
vapors from ignition sources.
• Proper PPE (hard hats, rubber boots, gloves,
suits, full body harness, etc.).
• Enter with supplied fresh air.
• Monitor vapors inside the manway away from
inlet.
• OSHA allows tank entry below 10% LEL for
fresh air work; however, the goal is to be
significantly lower.
Hose Extends from Vacuum Truck
to Tank Manway
Vacuum Truck Exhaust Connected
to Carbon Canister
Manway Setup – Plastic Sheet, Fire
Extinguisher, Confined Space Permits
Intrinsically Safe Fan Mounted on
Opposite Manway from Entrance
PPE for Tank Entry
Interior Appurtenances Removed to
Drain Product
Center Column Mouse Hole
Drained of Product
Marine Chemist Certifies the Tank
as Gas Free
The gas free
certificate is posted
over the manway.
It may have certain
restrictions to be
aware of.
Confined Space Access is Secured when
the Contractor Leaves the Site
Cribbing Blocks Installed to
Support Roof
Anti-Rotational Roof Support
API 653 Tank Inspection
Techniques
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Magnetic Flux Exclusion (MFE)
Ultrasonic Testing (UT)
Vacuum Box Testing
Dye Penetrant Testing
Bottom Settlement Survey
Calibration of Magnetic Flux
Exclusion (MFE) Bottom Scanner
Large MFE/UT Floor Scanner
Scans within 2” of Lap Weld Seams
Marking Corrosion Indications
Circles – Topside Corrosion
Square – Bottomside Corrosion
Calibration of Smaller Hand
Scanner
Smaller Scanner in Congested
Area
Hand Scanner used at Corner
Weld
Remaining Floor Thickness is Marked in
Area of Soil Side Corrosion
Automated Ultrasonic Thickness Measurement
used to “Prove Up” locations marked during MFE
Scan
Vacuum Box Testing of Corner Weld
Vacuum Box Testing of Floor Plate Weld
Seam
Fluorescent Dye Penetrant Applied
to Corner Weld
Using Black Light to Find Defects
Detected with Fluorescent Dye
Bottom Settlement Survey
Ultrasonic Testing of Tank Shell
Ultrasonic Testing of Shell
Reinforcement Pad and Nozzle
Ultrasonic Testing of Internal
Floating Roof
Tank Repairs
Tank Repairs
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Floor Patches and Plate Replacements
Shell Repairs
IFR Repairs
Nozzles
Seal Replacement
Tank Valve Repairs
Calibration and Repair of Gauging System
Follow-up Testing
Testing of Vapors Beneath Tank Floor
Through Small Hole Drilled in the Floor
Bottom Repair at Critical Zone
Testing New Patch With Soapy Water
Dye Penetrant Testing of Shell
Nozzle
Roof Drain Hose Inspection
Replacing Seal Apron Fabric
Fluorescent Testing Beneath IFR
Inspecting the Penetrant Test Above
the Roof to Search for Leaks
Pressure Testing Pontoons
Following Repairs
Tank Interior Coating
SPCC Compliance
Purpose of SPCC Rule
• Requirements help prevent oil discharges
from reaching navigable waters or adjoining
shorelines.
• Certain facilities are required to develop
SPCC Plans that describe equipment,
workforce, procedures, and training to
prevent, control, and provide adequate
countermeasures to a discharge of oil.
– Must comply with the rule requirements.
– Must also implement the written Plan.
What does the SPCC Rule Require?
• Requires facilities to develop and implement a
site-specific SPCC Plan to address:
– Containment and procedures to prevent oil discharge
(operating procedures, inspections & tank testing,
training, etc.)
– Control measures to keep an oil discharge from
entering navigable waters (containment, drainage
valves
– Countermeasures to contain, clean up, and mitigate
any oil discharge that affects navigable waters (spill
response measures)
• Performance-based rule designed to implement
the Congressional policy of “no oil discharges” to
waters of the United States
Aboveground Petroleum Storage
Tank Act (APSA)
What is an Aboveground Petroleum
Storage Tank?
• 55 gallons or more.
• Located substantially above ground.
• Tanks are either UST or AST, but not
regulated as both.
• The volume for mixtures is based on the
total tank capacity not the volume of
petroleum in the mixture.
APSA Exemptions
• Two broad exemptions:
– Exempt Tanks (HSC §25270.2(a)(1 – 6))
• Some exemption conditions (and compliance with
those conditions) should be verified
– Exempt Facilities (HSC §25270.4.5(b))
• Exempt only from APSA requirement to prepare
and implement an SPCC Plan
Tanks Exempted Under APSA
• Boilers & pressure vessels
• Waste & used oil tanks
– Located at DTSC permitted hazardous waste
TSD facilities (and listed on the permit), or
specifically listed on a facility’s PBR Tiered
Permit
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Crude oil production tanks
Most oil-filled electrical equipment
CUPA regulated USTs
Transportation-related tank facility
APSA (and SPCC Rule) Exempt Tanks
• ‘Transportation-related facilities’ are not
regulated under federal SPCC rules or APSA
• Facilities are divided into three categories:
– Transportation-related facilities (exclusively regulated
by DOT / DOI)
– Non-transportation-related facilities (not exclusively
regulated by DOT / DOI)
– Complexes (regulated by both)
• Jurisdiction was established through a series of
Executive Orders (EOs) and Memoranda of
Understanding (MOUs)
EOs and MOUs
• Executive Order 11548 delegated responsibilities for
regulating oil discharges (later superseded by E.O.
11735 and 12777).
– EPA: Non-transportation-related facilities
– DOT: Transportation-related facilities
• EPA-DOT MOU (1971) defines transportation- and
non-transportation-related.
• DOT-DOI-EPA MOU (1994) establishes
responsibilities for offshore facilities, including
pipelines.
Non-Transportation-Related Facilities
(CUPA Jurisdiction under APSA)
• Oil refining and storage facilities
• Industrial, commercial, non-exempt agricultural,
and public facilities that use and store oil
• Waste treatment facilities
• Loading areas and racks, transfer hoses, loading
arms, and other equipment used to transfer oil in
bulk to or from highway vehicles or railroad cars
• Highway vehicles, railroad cars, and pipelines
used to transport oil within confines of nontransportation-related facility
Transportation-Related Facilities
(DOT Jurisdiction)
• Onshore and offshore terminal facilities, including
transfer hoses, loading arms, and other equipment
used to transfer oil in bulk to or from a vessel;
including storage tanks and appurtenances for the
reception of oily ballast water or tank washings from
vessels
• Transfer hoses, loading arms, and other equipment
appurtenant to a non-transportation-related facility
used to transfer oil in bulk to or from a vessel
• Interstate and intrastate onshore and offshore pipeline
systems
• Highway vehicles and railroad cars that are used for
the transport of oil
Complexes
(CUPA and DOT Jurisdiction)
• A facility with both transportation-related
and non-transportation-related activities is
a “complex facility” and is subject to the
dual jurisdiction of the CUPA under APSA
and DOT.
Underground Piping Associated
with Aboveground Tanks
• APSA does regulate buried piping.
• The federal SPCC regulations contain
requirements for buried piping at a
regulated facility and APSA requires the
implementation of the SPCC Plan for
ASTs.
APSA Regulated Piping
• Must be connected to the tank.
• APSA applies to:
– Piping in the containment area.
– Piping up to the first valve or flange outside the
containment area.
– If there is no containment, piping connected to the
first flange or valve.
• Federal SPCC rules for the facility may be
broader and include piping not integrally related
to the storage tank.
APSA (SPCC) Compliance Verification
• Written Plan review
– All rule-required content (and format)
– Facility-specific descriptions, procedures, etc.
• Can be narrative, generic
• Inspect for compliance with the detailed rule
requirements
– Whether adequately described in the Plan or not
• Verifying the written Plan is consistent with
field conditions
• Verifying that the facility is implementing the
Plan as written
DOT Compliance
Applicable DOT Regulations
• Applicable to breakout tanks and pressure
relief tanks at petroleum transportation
facilities.
• DOT views the tanks as part of the
pipeline.
• CFR Title 49 – Transportation.
– Part 195 – Transportation of Hazardous
Liquids by Pipeline.
Applicable Sections of DOT
Regulations for Tanks
• 195.132 -- Design and Construction of
Above Ground Breakout Tanks.
• 195.307 -- Pressure Testing Above
Ground Breakout Tanks (hydrostatic
testing).
• 195.432 -- Inspection of In-Service
Breakout Tanks.
• Subpart G -- Operator Qualification (OQ)
Training Program.
DOT Applicable Regulations
Part 195.432 “Each operator must inspect the
physical integrity of in-service atmospheric and
low-pressure steel aboveground breakout tanks
according to API Standard 653 (incorporated by
reference, see §195.3). However, if structural
conditions prevent access to the tank bottom,
the bottom integrity may be assessed according
to a plan included in the operations and
maintenance manual under §195.402(c)(3).”
Air Regulations
Air Compliance
• Air Compliance rules are confusing,
complex, and sometimes conflicting.
• This presentation will just provide a broad
outline of rules.
• Rule applicability determination depends
on:
– the year the tank was built,
– tank volume,
– vapor pressure of liquid.
Clean Air Act (CAA) Regulations
• Ozone Precursors (VOCs) – Title 1, the
source is the individual tank.
– NSPS Rule, 40CFR Part 60
• Subpart K – Effective 6/11/73
• Subpart Ka – Effective 5/18/78
• Subpart Kb – Effective 7/23/84
– Control Technology Guidelines (CTG),
Reasonably Available Control Technology
(RACT) rules
Clean Air Act Regulations (Con’t)
– Control Technology Guidelines (CTG),
Reasonably Available Control Technology
(RACT) rules.
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Applies to existing source in non-attainment areas.
1977 Fixed Roof Tank.
1978 EFR Tank.
1994 ACT for VOL Storage.
Clean Air Act Regulations (Con’t)
• Air Toxics – Hazardous Air Pollutants
(HAPs Rule), Title III
– NESHAPS (40 CFR Part 61).
• These rules are specific to individual chemical in
individual tanks.
• Subpart Y is for Benzene.
– NESHAPS (40 CFR 63)
• Rule applies to all HAPs and the source is the
entire facility.
Clean Air Act Regulations (Con’t)
– NESHAPS (40 CFR 63) – Continued
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SOCMI HON
Gasoline Distribution
Petroleum Refineries
Oil and Gas Production (a.k.a. – E&P MACT)
Organic Liquids Distribution (a.k.a. – Old MACT)