Crude oil Storage Tanks-Basics

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

• 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 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 • 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

• 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

• 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 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

• Scope

• Reference

• Definitions

• Suitability for Service

• Brittle Fracture

• Inspection

• Materials

• Design Considerations

• Tank Repair and

Alterations

• Dismantling/Reconstr

uction

• 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.


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.


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

• 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)

• 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

• 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

• 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

• 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 non-transportation-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.

• Applies to existing source in non-attainment areas.

• 1977 Fixed Roof Tank.

• 1978 EFR Tank.

• 1994 ACT for VOL Storage.


• 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.


– NESHAPS (40 CFR 63) – Continued

• SOCMI HON

• Gasoline Distribution

• Petroleum Refineries

• Oil and Gas Production (a.k.a. – E&P MACT)

• Organic Liquids Distribution (a.k.a. – Old MACT)

Crude oil Storage Tanks-Basics

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