United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-420) WF
500/B-92/001
April 1992
&EPA Introduction to Leak
Detection
Understanding Federal
Release Detection
Requirements and Acceptable
Release Detection Methods
nstructor Manual
Printed on Recycled Paper
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Contents
Page
NOTES TO THE INSTRUCTOR vii
CHAPTER ONE: BASIC LEAK DETECTION 1
I. OVERVIEW OF LEAKING UNDERGROUND STORAGE TANK SYSTEMS
(USTs) 1
A. The problem 1
B. Releases 2
C. Uses and ownership of USTs 2
II. LEAK DETECTION 3
A. What does leak detection accomplish? 3
B. Why is leak detection necessary for owners and operators of USTs? 3
III. LEAK DETECTION METHODS 5
A. Internal leak detection methods 5
B. Interstitial leak detection methods 5
C. External leak detection methods 5
D. Piping monitoring : 6
IV. OTHERS SOURCES OF INFORMATION ON THE UST PROGRAM 7
CHAPTER TWO: UST WALK-THROUGH 1
I. WHAT IS AN UST? 1
II. UST SYSTEM PARTS 3
A. Tanks 3
B. Piping 3
C. Product dispensers 4
D. The site 5
CHAPTER THREE: SITE CHARACTERISTICS i
I. UST SYSTEM CHARACTERISTICS 2
A. Tank age (new vs. existing) 2
B. Tank size 2
C. Piping system 2
D. UST system size 3
II. PRODUCT CHARACTERISTICS 4
A. Types of stored product 4
B. Characteristics of stored products 5
iii
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Contents
III.
IV.
V.
CHAPTER
1.
II.
III.
CHAPTER
1.
F
SOIL CONDITIONS: BACKFILL & SURROUNDING SOIL
A. Relative porosity
B. Hydraulic conductivity
C. Contamination
CLIMATIC FACTORS
A. Temperature
B. Rainfall
GEOLOGIC CONDITIONS
A. Effects of ground water
B. Important ground-water variables
FOUR: LEAK DETECTION METHODS FOR TANKS
GENERAL LEAK DETECTION REQUIREMENTS
A. Deadlines
B. Leak detection methods allowed
C. Requirements for probability of detection/probability of false alarm
D. Standard test procedures
LEAK DETECTION METHODS: MONTHLY MONITORING
A. Automatic tank gauging systems (ATGS)
B. Manual tank gauging (MTG)
C. Secondary containment with interstitial monitoring
D. Ground-water monitoring
E. Vapor monitoring systems
F. Statistical inventory reconciliation (SIR)
LEAK DETECTION METHOD: INVENTORY CONTROL & TIGHTNESS TESTING
A. Inventory control
B. Tank tightness testing
FIVE: LEAK DETECTION METHODS FOR UST PIPING
UST PIPING
A. Pressurized piping systems
B. Suction piping systems
'age
8
8
8
9
10
10
10
11
11
11
1
1
1
2
2
3
4
4
8
12
16
21
23A
24
24
29
1
1
1
1
IV
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Contents
III.
III.
V.
V.
APPENDICES
1.
II.
III.
LEAK DETECTION FOR UST PIPING
A. Deadlines
B. Requirements
C. Methods
D. Requirements for PD/PFA
E. Standard test procedures
AUTOMATIC LINE LEAK DETECTORS
A. Automatic flow restrictors
B. Automatic flow shutoff devices
LINE TIGHTNESS TESTS
A. Direct volumetric line tightness test
B. Indirect line tightness test
MONTHLY MONITORING METHODS
A. Secondary containment with interstitial monitoring
B. Ground-water monitoring
C. Vapor monitoring
D. Statistical inventory reconciliation
GLOSSARY OF LEAK DETECTION TERMS
EXERCISES
A. Case Study Guideline
B. UST Site Characteristics
C. Automatic Tank Gauging Systems
D. Ground-Water Monitoring
E. Vapor Monitoring
SLIDE SECTION
Page
3
3
4
5
6
6
7
7
8
11
11
13
15
15
17
19
21
1-1
11-1
11-1
II-3
II-5
II-7
II-9
111-1
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VI
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NOTES TO THE INSTRUCTOR
Welcome to "Introduction to Leak Detection." This course presents State and local UST program staff
with a review of acceptable methods of release detection. The training should enable them to understand
leak detection methods and to help UST owners and operators make an educated choice among leak detec-
tion course answers such questions as:
. What are the Federally accepted methods of leak detection?
What are the requirements for monitoring USTs?
What methods are used for leak detection in UST piping systems?
What site characteristics should be considered when deciding on the proper leak detection
method for a certain UST?
What are the advantages and the limitations of the various leak detection methods?
How do each of the methods compare in operation and maintenance?
These questions will be addressed by means of a variety of instructional methods: class lectures,
slide presentations, large and small group discussions, question and answer sessions, and case study
exercises. As an instructor, you should be prepared to present the material in the course as well as to answer
the questions and address the concerns of your students. The course has been designed to give you numer-
ous opportunities to incorporate scenarios and examples that illustrate your experiences and relate the course
material to situations unique to your locale. The more specific the information presented in this course, the
more effective the course will be.
Course Materials
The materials in this package are designed to assist the instructor throughout the entire course.
Three types of materials are provided: The instructor's manual' a student manual1 and visual aids such as text
slides, photographic slides, and graphic slides. You will also find a series of illustrative exercises at the end of
the manual. These resources will be sufficient for a complete training program, but it is suggested that you
incorporate other materials, as appropriate.
The instructor's manual is arranged in a two-column format. The left column contains the text of the
student manual. The right column provides space for your notes, as you are encourage to add State-specific
material and personal experience anecdotes regarding leak detection. The right column also provides
prompts for using the accompanying slides and exercises. (Slide material is described below; see Appendix II
for exercises.)
To help you visually present the course, numerous slides are provided in the slide box that is part of
this training package. Slides are numbered consecutively for each chapter. Hard copies of each text and
graphic slide are provided in the "Slide Section," so you can easily review the slides as you tailor the course
to your needs. Text slides act as prompts for both student and instructor by following the content of the
course in outline form. Graphic slides and photo slides illustrate concepts and equipment being discussed.
(The "Slide Section" does not include hard copies of the photo slides.) You are especially encouraged to
supplement the slides or replace them with others that are more appropriate for the situations your students
are most likely to encounter.
vii
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The student's manual is also arranged in a two-column format. The left column contains the
same text found in the left column of the instructor's manual. The right column labeled 'Student
Notes' indicates only slide numbers; most of the column has been left blank to provide space for
notes. The student's manual also provides definitions of terms in a glossary, and hard copies of most
graphics.
Preparing to Deliver the Course
Because instructors for this course will have various levels of teaching experience, the
following suggestions and teaching hints are provided to make teaching this course a more pleasant
and productive experience. Keep in mind that these are suggestions and may be incorporated into
the course as you feel necessary.
Effective instruction requires careful preparation by the instructor. The more familiar you are
with the course materials, the easier the delivery of the course will be.
Study the instructor's and student's manuals.
Review the reference materials, and select slides and other materials to assist you in
your presentation. Remember that you are encouraged to incorporate supplemental
materials specific to your State. Research for ideas, facts, and anecdotes that will
apply to your situation. (Examples of specific situations include coastal areas, where
tides affect the water table, or areas with extreme temperature changes that may affect
tank testing procedures).
Practice your presentation and use of the visual aids. Get a feel for the length of time
that will be required to cover the material. Remember to include time for questions.
Make notes to yourself on items you want to cover that are not included in the
manuals. It is very easy to forget to include something, once you have begun
instruction.
Contact other instructors who have presented the course to learn from their
experiences.
You may choose to send out an advance registration form to participants requesting
information on their work experience. This may help you to shape the course
materials for a specific audience.
The following are suggestions you may want to consider just prior to delivery of the course:
Prepare and check all materials, training aids, and equipment needed for each class.
Make sure that you have enough copies of the required materials for the number of
students, and include a few extra copies for late registrations.
Check your meeting facilities for lights, heat, chair set-up, and anything else that might
affect the comfort of the students while the course is being conducted.
Review each chapter for its goals and objectives.
VIII
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The following are suggestions to consider while giving the presentation:
Make sure that all students can hear you, and that they can see the slides.
Try to pace your speaking pattern. A nervous instructor tends to talk too fast. Taking
a few deep breaths now and then will help.
Introduce each new unit with an overview of what the student is going to learn.
Close each unit with a brief overview of what was presented.
Make sure to allow time for questions. You may decide to ask students to hold all
questions until the end of a unit, or you may tell them that they may ask questions at
any time.
Applicability of OUST Publications
EPA's Office of Underground Storage Tanks (OUST) has developed many publications and
videos that you may find useful as training tools. You will find a list of these materials at the end of
Chapter One.
In addition, you should be aware of an additional resource not included on that list: a series
of publications appearing under the general title of 'Standard Test Procedures for Evaluating Leak
Detection.' Each publication in the series presents a detailed, highly technical procedure for testing
one of the leak detection methods. Each publication includes a form that can be used to verify that
the method being described meets EPA standards. Although tank owners and government regulators
are not likely to need the actual, detailed test procedures, you may find some of the information
applicable to your training. The series includes the following:
Automatic Tank Gauging Systems (45A)
Liquid-Phase Out-of-Tank Product Detectors (45B)
Non-Volumetric Tank Tightness Test Methods (45C)
Pipeline Leak Detection Systems (45D)
Statistical Inventory Reconciliation Methods (45E)
Vapor-Phase Out-of-Tank Product Detectors (45F)
Volumetric Tank Tightness Test Methods (45G)
Entire set of seven titles above (45SET)
The "Standard Test Procedures' series has been available in limited quantities since 1990 and there
may already be copies in your office. If you need a copy, you can place an order (at no cost) by
using the order numbers indicated above and sending your request to:
U.S. Environmental Protection Agency
Office of Underground Storage Tanks
P.O. Box 6044
Rockville, MD 20850
Questions and Feedback
If you have questions or would like to comment on the contents of the training package,
please contact the Office of Underground Storage Tanks, U.S. EPA, at (703) 308-8850.
IX
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CHAPTER ONE
BASIC LEAK DETECTION
This chapter will introduce you to the problem of leaking underground storage tanks, leak detection
and what it accomplishes, and why leak detection is necessary. It will also provide an overview of
several leak detection methods. The chapter will serve as an introduction for some participants, and
as a review of the material for others with more experience. This information provides the background
necessary for understanding the following chapters.
Lecture Notes
Instructional Aids
OVERVIEW OF LEAKING UNDERGROUND
STORAGE TANK SYSTEMS (USTs)
A. The problem
1. Petroleum and chemicals are
stored in underground storage
tanks, many of which are vulner-
able to corrosion.
84 percent of service station
tanks are made of bare
(unprotected) steel and are
highly susceptible to cor-
rosion.
15 - 20 percent of petroleum
tanks may be leaking, which
means that hundreds of
thousands of USTs may be
leaking.
2. Leaking tanks pose a threat to
ground water. Releases from
USTs into water supplies used for
drinking and other purposes can
endanger public health.
3. The threat of leaking tanks is not
limited to ground water. Other
considerations are:
Contamination of surface
waters;
Slide 1: Chapter One slides.
Note: Each slide is numbered, and corresponds
to a specific section in the manual.
Note: Text in this column is designed to assist
you with talking points. You are encouraged to
incorporate scenarios and examples throughout
the course.
Slide 1A (photo): Leaking tank.
Slide 2: This slide presents the topics to be
covered in Chapter One.
Slide 3 (graphic): This pie graph illustrates the
number of tanks that are unprotected, and there-
fore highly susceptible to corrosion.
Slide 4: Discuss the problem of leaking USTs.
Include specific numbers of the UST universe in
your area, and the specific types of health and
environmental threats that have resulted.
Slide 5: Discuss other risks associated with
leaking USTs.
Note: Although ground-water contamination is a
major concern, there are other problems that
have to be addressed.
Chapter One, Page 1
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Lecture Notes
Instructional Aids
4.
Fires and explosions; and
Toxic fumes that seep into
homes and businesses.
Two components of gasoline,
benzene and ethyl dibromide, are
suspected cancer-causing
agents.
B. Releases
1. Releases result from piping fail-
ure, spills and overfills, and tank
corrosion.
2. When a release occurs, product
can:
Seep through the soil into
the ground water;
Float on top of the water
table;
Discharge into wells or sur-
face water; and/or
Seep into underground
structures (pipelines, utilities,
lines, basements, etc.).
C. Uses and ownership of USTs
1. The largest percentage (39 per-
cent) of regulated USTs are used
in retail motor fuel businesses.
2. The second largest user of USTs
(38 percent) is the non-retail
motor fuel sector, such as rental
companies and government
agencies.
3. Nearly 80 percent of all USTs
used to store petroleum are
owned and operated by gas sta-
tions and industry. Government
and farmers each own about half
of the remaining 20 percent.
Farm tanks with a capacity of
1,100 gallons or less used for
storing motor fuel for noncommer-
cial purposes are not subject to
Federal UST regulations.
Slide 6: Discuss the three types of releases
mentioned. Most of the releases occur due to
piping failures.
Slide 7 (graphic): Use this graphic to point out
the ways that released product can travel.
Slide 8 (graphic): Use this pie chart to discuss
the uses of regulated USTs. Note that the larg-
est percentage of USTs contain motor fuels.
This course will focus on these tanks.
Slide 9 (graphic): Use this pie chart to discuss
the ownership of the petroleum USTs.
Chapter One, Page 2
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Lecture Notes
Instructional Aids
II. LEAK DETECTION
A. What does leak detection
accomplish?
1. Leak detection warns owners and
operators of leaks in tanks and
piping. Early warning enables
owners and operators to take
action to stop the escape of large
amounts of the product into the
environment.
2. Leak detection can prevent
ground-water contamination.
B. Why Is leak detection necessary for
owners and operators of USTs?
1. Detecting leaks is a good busi-
ness practice.
Loss of product costs the
owner/operator money.
Extensive releases can be
very costly to clean up.
USTs that pollute a com-
munity's environment can
cause public relations prob-
lems.
2. Detecting leaks protects human
health and the environment.
Leak detection helps prevent
the contamination of ground
water that may be used as
drinking water. Half of the
U.S. population relies on
ground water as a source of
drinking water.
Petroleum and chemicals
stored in USTs can con-
taminate the soil, air and
water with harmful effects to
people, plants, and animals,
particularly in farm produc-
tion.
Slide 9A (photo): Current headlines demon-
strate the increasing amount of public aware-
ness.
Slide 10: Discuss the effects of leak detection:
it warns the owner/operator of leaks and pre-
vents environmental contamination and risks to
human health.
Slide 11: Emphasize the cost benefits of leak
detection.
Note: The average cost of a cleanup now is
$150,000.
Slide 12: Discuss the four main reasons for leak
detection.
Note: Many service stations want to promote
good public relations and avoid bad publicity.
Leak detection demonstrates to the community
that the owner/operator is concerned about
safety.
Chapter One, Page 3
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Lecture Notes
Instructional Aids
Leaking tanks also can lead
to explosions, fires, toxic
fumes, and contaminated
surface waters.
Detecting leaks can protect
owners and operators against
liability suits.
Local residents and com-
munities can take damage
claims to court.
Detecting leaks is required by
Federal, State, and local laws.
LIST regulations require
preventing, detecting, and
cleaning up leaks and spills.
Chapter One, Page 4
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Lecture Notes
Instructional Aids
III. LEAK DETECTION METHODS
Three types of methods detect leaks from
tanks:
Internal monitoring:
Interstitial monitoring; and
External monitoring.
In addition, piping has special leak detection
requirements.
A. Internal leak detection methods
These methods monitor inside the tank to
check for leaks, and frequently measure
volume loss over time of test. There are four
types of internal monitoring:
1. Inventory control combined with tightness
testing;
2. Manual tank gauging;
3. Automatic tank gauging; and
4. Statistical inventory reconciliation.
B. Interstitial leak detection methods
These methods monitor the area between the
tank and a containment barrier.
C. External leak detection methods
These methods use sensors to monitor the
environment surrounding the tank for the
presence of the leaked product. There are two
types of external monitoring:
1. Vapor mon itoring; and
2. Ground-water monitoring.
Slide 13: There are three main types of leak de-
tection. Each method will be discussed in
detail during the remaining chapters of the
course.
Note: A video is available that reviews each type
of leak detection except for statistical
inventory reconciliation. For information on
ordering this 25-minute video, "Straight
Talk on Leak Detection with Joe Thursday,"
see the publication list and order form at
the end of this chapter. You may want to
show the video in lieu of this portion of the
chapter.
Slide 14: Discuss these methods briefly.
Slide 15: Discuss briefly.
Slide 16: Discuss briefly.
Chapter One, Page 5
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Lecture Notes
Instructional Aids
D. Piping monitoring
1. Requirements for pressurized
piping and suction piping are not
the same.
Compliance deadlines; and
Testing requirements.
2. Pressurized piping must have
automatic line leak detectors to
prevent catastrophic releases.
3. There are three types of leak
detection for piping:
Tightness testing;
Interstitial monitoring; and
External monitoring.
Slide 17: Mention the differences between
these types of piping systems.
Slide 18: Mention that the methods of leak
detection are generally the same as those for
tanks, but piping may be tested either as part of
the whole tank system, or separately.
Chapter One, Page 6
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Lecture Notes
Instructional Aids
IV. OTHER SOURCES OF INFORMATION ON
THE UST PROGRAM
In addition to the materials in this manual,
the UST program also has developed hand-
books, slide shows, and video tapes on a
wide range of topics to inform States, local-
ities and regulated industries about the
regulations and program requirements.
Many of these materials may be of interest
to you.
Additional information sources have been
provided for you on the next few pages of
this manual, including publication and video
order forms and a list of UST Regional and
State contacts.
In addition to these materials, the EPA
RCRA/Superfund Hotline (1-800-424-9346)
can assist you with specific questions about
the UST regulatory requirements.
Slide 19: Use this slide to review the chapter.
Remind students that each method will be dis-
cussed in detail, for both tanks and piping.
Chapter One, Page 7
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U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF UNDERGROUND STORAGE TANKS
PUBLICATIONS LIST
General Information ORDER NO.
Notification for Underground Storage Tanks: EPA Form 7530-1 (Revised 9-88) 5
Hazardous Substance List 7
Here Lies the Problem 39
LUSTLINE Bulletin 10
Normas y Procedimientos para T.S.A. (Spanish version of Musts for USTs, an Overview of Federal
Technical UST Standards) 26S
Managing Underground Storage Tanks (brochure to order a slide show) 40
Straight Talk on Tanks (Leak Detection Summaries) 49
"Oh No! Leaks and Spills!" - First Response (brochure) 73
Leak Lookout (External Leak Detectors) 74
Introducing Reg-ln-A-Box (ordering flier) 84
Regulations
Notification of Requirements for Owners of Underground Storage Tanks; Final Rule 40 CFR Part 280
(Federal Register 11/8/85) 3
Underground Storage Tanks: Technical Requirements and State Program Approval; Final Rule 40 CFR
Parts 280 & 281 (Federal Register Part II9/23/88) 4A
Underground Storage Tanks Containing Petroleum; Financial Responsibility Requirements and State Program
Approval Objective; Final Rule 40 CFR Parts 280 & 281 (Federal Register Part I110/26/88), Underground
Storage Tanks Containing Petroleum; Financial Responsibility Requirements; Interim Final Rule 40 CFR
Part 280 (Federal Register 11/9/89, 5/2/90) 4B
Hazardous Waste; Interim Prohibition Against Installation of Unprotected Underground Storage Tanks;
Interpretive Rule 40 CFR Part 280 (Federal Register 6/4/86) 17
Subtitle I. Hazardous and Solid Waste Amendments of 1984; RCRA 21
Technical Reports
Causes of Release From UST Systems 32
Tank Corrosion Study 42
Estimating Air Emissions from Petroleum UST Cleanups . 88
Detecting Leaks. Successful Methods Step-by-Step 92
ORDER FORM
Name: Title:.
Organization:
Street:
City: State: Zip:.
Telephone: ( ) -
Please return this form to:
U.S. Environmental Protection Agency
Office of Underground Storage Tanks
P.O. Box 6044
Rockville, MD 20850
Please send me the
publications I have circled:
3 4A 4B 5 7
10 17 21 26S 32
39 40 42 49 73
74 84 88 92
UST25
6/17/91 SPEC
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Other Publications of Interest
TITLE/STOCK NO.
COST
AVAILABLE FROM
Musts for USTs: A Summary of the Regulations for
Underground Storage Tank Systems
Stock No. 055-000-00294-1
Dollars and Sense: A Summary of the Financial
Responsibility Regulations for Underground Storage
Tank Systems
Stock No. 055-000-00293-2
Cleanup of Releases from Petroleum USTs: Selected
Technologies
Stock No. 055-000-00272-0
Field Measurements: Dependable Data When You Need It
Stock No. 055-000-00368-8
Petroleum Tank Releases Under Control: A Compendium
of Current Practices for State UST Inspectors
Stock No. 055-000-00295-9
Survey of Vendors of External Petroleum Leak Monitoring
Devices for Use with USTs
Stock No. 055-000-00277-1
$2.50
$1.25
$7.50
$5.50
$8.50
$4.25
Superintendent of Documents
U.S. Government Printing Office
Washington, D.C. 20402
(202) 783-3238
Visa and MasterCard accepted
Evaluation of Volumetric Leak Detection Methods for
Underground Fuel Storage Tanks
Volume 1. No. PB89-124333 paper/microfiche
Volume 2. No. PB89-124341 paper/microfiche
Underground Storage Tank Corrective Action
Technologies
PB 87-171278 paper/microfiche
National Technical Information Service
5285 Port Royal Road
$39.00/$8.00 Springfield, VA 22161
$81.00/$21.50 (703) 487-4600
$31.00/$8.00
Soil Gas Sensing for Detection and Mapping of Volatile
Organlcs
Catalog No. TO49
$35.007 National Water Well Association
member P.O. Box 182039, Dept. 017
$43.757 Columbus, OH 43218
non-member (614) 761 -1711
Reg-ln-A-Box personal computer (PC) software is an $5.00
aid to understanding and working with the Federal UST plus shipping
regulations. Easy to use and available for PC-compatibles and handling
with hard disk drives. Not copy protected.
Public Brand Software
1-800^426-3475 (24 hours a day)
(317)856-7571 (in Indiana)
Visa and MasterCard accepted
Volumetric Tank Testing (Summary of Edison Study
on Internal Leak Detectors)
Stock No. 625/9-89/009
Free
Center for Environmental Research
Information
26 West Martin Luther King Drive
Cincinnati, OH 45268-1072 I
(513) 569-7562
6/17/91 SPEC
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Audiovisual Programs
DEOS
AVAILABLE FROM
"Straight Talk on Leak Detection"
(An introductory overview for owners and operators of underground storage tank
systems on the leak detection methods available for complying with LIST
regulations [Total 35 minutes].)
Part 1: Straight Talk From Tank Owners. (Owners address the problems of
LIST compliance [5 minutes].)
Part 2: Straight Talk on Leak Detection with Joe Thursday (30 minutes).
Cost: $40.00 prepaid
"Doing It Right"
(Proper installation of underground tanks and piping for installation crews.)
Part 1: Tanks (24 minutes)
Part 2: Piping (16 minutes)
Cost: $16.00 prepaid
Environmental Media Center
P.O. Box 30212
Bethesda, MD 20814
OR CALL TOLL FREE:
1-800-522-0362
(301-229-1944 in Maryland)
Visa and MasterCard accepted
"Searching for the Honest Tank: A Guide to LIST Facility Compliance
Inspections"
(Covers major steps of UST inspections from protocols and equipment to
enforcement and followup; from cathodic protection to leak detection. Although
is directed at inspectors, the video is also helpful to owners and operators
minutes].)
Video and Booklet Cost: $40.00 prepaid
Booklet Cost: $5.00 prepaid
New England Interstate
Environmental Training Center
Attn: VIDEOS
2 Fort Road
South Portland, ME 04106
"Tank Closure Without Tears: An Inspector's Safety Guide"
(Focuses on problem of explosive vapors and safe tank removal.)
Video and Booklet Cost: $30.00 prepaid
Booklet Cost: $5.00 prepaid
"What Do We Have Here? An Inspector's Guide to Site Assessment at
Tank Closure."
(A three-part video on inspecting sites for contamination where tanks have been
removed.)
Part 1: Site Assessment Overview (30 minutes)
Part 2: Field Testing Instruments at a Glance (14 minutes)
Part 3: Soil and Water Sampling at a Glance (7 minutes)
Video and Booklet Cost: $45.00 prepaid
Booklet Cost: $5.00 prepaid
"A Question of When: Tank Installation for Inspectors"
(Tank and pipe installation with a checklist for inspectors [28 minutes].)
Cost: $32.85 prepaid
"In Your Own Backyard"
(What tank owners should require from installation contractors [22 minutes].)
Cost: $32.85 prepaid
TZ Communications
P.O. Box 332
Holbrook, MA 02343
6/17/91 SPEC
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Audiovisual Programs
SLIDES AVAILABLE FROM
"Managing Underground Storage Tanks" National Audiovisual Center
(Segments on all phases of tank management from inventory and installation to Customer Services Section/WD
leak detection and clean up.) 185 slides, 27-page script, and 103 pages of 8700 Edgeworth Drive
graphics. Capitol Heights, MD 20743-3701
Cost: $120.00 (301)763-1891
"Tank Talk: The New National Rules" Capital Presentations
(A visual overview of the Federal rules for USTs - - technical standards and 10 Post Office Road - Suite 2N
financial responsibility.) 70 slides, 20-page script, and 30-minute narrated Silver Spring, MD 20910
audio tape. (301)588-9540
Cost: $80.00
6/17/91 SPEC
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U.S. Environmental Protection Agency
Office of Underground Storage Tanks
Regional and State UST/LUST Program Contacts
HI
Guam
Am. Samoa LJ
CNMI
William Torrey
U.S. EPA, Region 1
JFK Federal Building
Mailcode: HPU-7
Boston, MA 02203
617-573-9604
FTS 833-1604
Dit Cheung
U.S. EPA, Region 2
Hazardous & Solid Waste
Programs Branch
26 Federal Plaza
Code: 2AWM-HSWPB
New York, NY 10278
212-264-3384
FTS 264-3384
Renee Gruber, Acting
U.S. EPA, Region 3
J1 Chestnut Building
lilcode: 3HW63
Philadelphia, PA 19107
215-597-7354
FTS 597-3177
EPA Regional UST Program Managers
John Mason
U.S. EPA, Region 4
345 Courtland St.. N.E.
Mailcode: 4WM-GWP-15
Atlanta, GA 30365
404-347-3866
FTS 257-3866
Gerald Phillips
U.S. EPA, Region 5
77 W. Jackson Blvd.
Mailcode: HRU-8J
Chicago, IL 60604
312-886-6159
FTS 886-6159
Samuel Coleman, Acting
U.S. EPA, Region 6
1445 Ross Avenue
Mailcode: 6H-A
Dallas, TX 75202-2733
214-655-6755
FTS 255-6755
Lee Daniels
U.S. EPA, Region 7
RCRA/STPG Branch
726 Minnesota Avenue
Kansas City, KS 66101
913-551-7055
FTS 276-7055
Debbie Ehlert
U.S. EPA, Region 8
999 18th Street
Mailcode: 8-HWM-WM
Denver, CO 80202-2466
303-293-1514
FTS 330-1514
Pat Eklund
U.S. EPA, Region 9
75 Hawthorne Street
10th Floor, H-2-1
San Francisco, CA 94105
415-744-2079
FTS 484-2079
Joan Cabreza
U.S. EPA, Region 10
1200 Sixth Avenue
Mailcode: WD-139
Seattle, WA 98101
206-553-1643
FTS 399-1643
UST93
3/92
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State UST/LUST Program Offices
AL
AR
AZ
CA
^UST/LUST CONTACT2
.AK Dept of Environmental Conservation
Contaminated Sites
410 Willoughby Avenue, Suite 105
Juneau.AK 99801-1795 907-465-5250
UST/LUST CONTACT
'AL Dept. of Environmental Management
Ground-Water Section/Water Division
1751 Congressman W. L. Dickinson Dr.
. Montgomery, AL 36130
UST: 205-271-7986
LUST: 205-271-7834
UST/LUST CONTACT1
AR Dept. of Pollution Control & Ecology
Regulated Storage Tank Division
P.O. Box8913,72219-8913
8001 National Drive
Little Rock, AR 72219-8913
501-562-6533
UST/LUST CONTACT2
. AZ Department of Environmental Quality
3033 North Central Avenue
Phoenix, AZ 85004 602-257-6984
UST/LUST CONTACT
CA State Water Resources Control Board
Division of Clean Water Program
201 4 T Street
.(P.O. Box 944212, Zip: 94244-2120)
ISacramento, CA 95814
UST: 9 16-739-4436
LUST: 916-739-4317
UST CONTACT
CO State Oil Inspection Office
1001 East 62nd Avenue, Room A1
Denver, CO 802 1 6 303-289-5643
LUST CONTACT
CO Department of Health
Hazardous Materials & Waste Mgmt. Div.
Underground Storage Tank Program
4210 East 11th Avenue
Denver. CO 80220 303-331-4864
UST/LUST CONTACT2
CT Dept. of Environmental Protection
Underground Storage Tank Program
165 Capitol Avenue
Hartford, CT 06106 203-566-4630
UST/LUST CONTACT2
DC Environmental Regulatory Admin.
Underground Storage Tank Branch
2100 Martin Luther King Ave. S.E.
Suite 203
Washington, D.C. 20020
202-404-1167
DE UST/LUST CONTACT2
DE Dept. of Natural Resources &
Environmental Control
Underground Storage Tank Branch
715Grantham Lane
Newcastle, DE 19720 302-323-4588
CO
CT
DC
FL UST/LUST CONTACT2
FL Dept. of Environmental Regulation
Tank Section
Twin Towers Office Building - Rm 403
2600 Blair Stone Road
Tallahassee, FL 32399-2400
904-488-3935
GA UST/LUST CONTACT1
GA Department of Natural Resources
- Underground Storage Tank Mgmt. Prog.
4244 International Parkway, Suite 100
Atlanta, GA 30354 404-362-2687
HI UST/LUST CONTACT1
HI Department of Health
Solid and Hazardous Waste Branch
500 Ala Moana Blvd., Suite 250
Honolulu, HI 96813-4913 808-586-4230
IA UST/LUST CONTACT1
IA Department of Natural Resources
Henry A. Wallace Building
900 East Grand
Des Moines, IA 50319 515-281-8135
ID UST/LUST CONTACT2
ID Department of Health & Welfare
ID Division of Environmental Quality
1410 North Hilton
Boise, ID 83706 208-334-5860
IL UST CONTACT
IL Office of State Fire Marshal
Division of Petroleum & Chemical Safety
1035 Stephenson Dr.
Springfield, IL 62703 217-785-5878
LUST CONTACT
IL EPA, Bureau of Land
Div. of Remediation Mgmt., LUST Section
P.O. Box 19276
Springfield, IL 62794-9276 217-782-6760
IN UST CONTACT
IN Dept. of Fire and Services
Office of the State Fire Marshal
402 West Washington Street
Room C241
Indianapolis, IN 46204 317-232-2222
LUST CONTACT
IN Dept. of Environmental Management
Office of Environmental Response
2321 Executive Drive
Indianapolis, IN 46241 317-243-5110
KS UST/LUST CONTACT
KS Department of Health & Environment
Bureau of Environmental Remediation
Underground Storage Tank Section
Forbes Field, Building 740
Topeka, KS 66620-0001
UST: 913-296-1685
LUST: 913-296-1684
KY
LA
MA
MD
ME
Ml
MN
UST/LUST CONTACT1
KY Division of Waste Management
Underground Storage Tank Branch
18 Reilly Road
Frankfort, KY 40601 502-564-6716
UST/LUST CONTACT2
LA Dept. of Environmental Quality
Underground Storage Tank Division
P.O. Box 82178, 7290 Bluebonnet
Baton Rouge, LA 70884-2178
504-765-0243
UST CONTACT
MA Department of Public Safety
Underground Storage Tank Program
P.O. Box 490, East Street, Bldg. #5
Tewksbury, MA 01876 508-851-9813
LUST CONTACT
MA Dept. of Environmental Protection
One Winter Street
Boston. MA 02108 617-556-1044
UST/LUST CONTACT1
MD Department of Environment
Hazardous & Solid Waste Mgmt. Admin.
Underground Storage Tank Program
2500 Broening Highway
Baltimore, MD 21224 410-631-3442
UST/LUST CONTACT1
ME Dept. of Environmental Protection
State House - Station 17
Hospital Street, Ray Building
Augusta, ME 04333 207-289-2651
UST CONTACT
Ml Department of State Police
Fire Marshal Division
P.O. Box 30157
MO
Lansing, Ml 48909
517-322-1935
LUST CONTACT
Ml Department of Natural Resources
Leaking Underground Storage Tank Unit
P.O. Box 30028
Lansing, Ml 48909 517-373-8168
UST/LUST CONTACT
MN Pollution Control Agency
Underground Storage Tank Program
520 Lafayette Road North
St. Paul, MN 55155-3898
UST: 612-297-8609
LUST: 612-297-8574
UST CONTACT
MO Department of Natural Resources
Water Pollution Control Program
P.O. Box 176
Jefferson City, MO 65102 314-751-6822
LUST CONTACT
MO Department of Natural Resources
Environmental Services Program
P.O. Box 176
Jefferson City, MO 65102 314-526-3349
State has 1 person serving as both the UST and LUST Contact.
2 = State has 1 UST and 1 LUST Contact; both have the same address and telephone number.
3/92
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State UST/LUST Program Offices
MS UST/LUST CONTACT1
. ... MS-Department of Environmental Quality ...t
- Bureau of Pollution Control
Underground Storage Tank Section
P.O. Box 10385
Jackson, MS 39289-0385
601-961-5171
MT UST/LUST CONTACT1
MI Dept. of Health & Environ. Science
Solid & Hazardous Waste Bureau
Cogswell Building - UST Program
Helena, MT 59620 406-444-5970
NC UST/LUST CONTACT2
NC Pollution Control Branch
Division of Environmental Management
Dept. of Env. Health & Natural Resources
441 N. Harrington St.
Raleigh. NC 27603 919-733-8486
ND UST/LUST CONTACT1
ND Department of Health
Division of Waste Management
> ' Box'5520,1200 Missouri Ave:,'Roomv302"
Bismarck, ND 58502-5520
701-221-5166
NE UST CONTACT
NE State Fire Marshal's Office
Flammable Liquid Storage Tank Division
246 South 14th Street
Lincoln, NE 68508 402-471-9465
LUST CONTACT
NE Dept. of Environmental Control
GroundwaterSect., Water Quality Division
301 Centennial Mall South, Box 98922
Lincoln, NE 68509-8922 402-471-4230
NH UST/LUST CONTACT1
NH Dept. of Environmental Services
Oil Compliance Section
Groundwater Protection Bureau
6 Hazen Drive, P.O. Box 95
Concord, NH 03301 603-271-3644
NJ UST/LUST CONTACT2
NJ Dept. of Environmental Protection
and Energy
Responsible Party Site Remediation
401 East State Street (CN-029)
Trenton, NJ 08625 609-984-3156
NM UST/LUST CONTACT1
NM Environment Department
Underground Storage Tank Bureau
P.O. Box 26110
1190 St. Francis Drive
Harold Runnels Building, Room N2150
Santa Fe, NM 87502 505-827-0188
NV UST/LUST CONTACT1
NV Dept. of Conservation & Natural Res.
Division of Environmental Protection
- . -,,., Capitol Complex
123W. NyeLane
Carson City, NV 89710 702-687-5872
NY UST/LUST CONTACT1
.-. '. NY Dept of Environmental Conservation
Bulk Storage Section
50 Wolf Road, Room 326.
Albany, NY 12233-3520 518-457-4351
OH UST/LUST CONTACT2
OH Department of Commerce
.-8895 East Main Street
P.O. Box 687
. Reynoldsburg, OH 43068
614-752-7938
OK UST/LUST CONTACT
OK Corporation Commission :
Underground Storage Tank Program
Jim Thorpe Building
2101 North Lincoln Blvd.
Oklahoma City, OK 73105
UST: 405-521-3107
LUST: 405-521-6575
OR UST CONTACT
OR Dept. of Environmental Quality
Underground Storage Tanks
811 SW Sixth Avenue, 7th Floor
Portland, OR 97204 503-229-5733
LUST CONTACT
OR Dept. of Environmental Quality
UST Cleanup Program
811 SW Sixth Avenue, 9th Floor
Portland, OR 97204 503-229-6170
PA UST/LUST CONTACT2
PA Dept. of Environmental Resources
BWQM, Storage Tank Program
3600 Vartan Way, 2nd Floor
P.O. Box 8762
Harrisburg, PA 17105-8762
717-657-4080
Rl UST/LUST CONTACT1
Rl Dept. of Environmental Management
Underground Storage Tank Section
291 Promenade St.
Providence. Rl 02908 401-277-2234
SC UST/LUST CONTACT
SC Dept of Health and Environ. Control
Ground-Water Protection Division
2600 Bull Street
Columbia, SC 29201
UST: 803-734-5335
LUST: 803-734-5331
SD UST/LUST CONTACT1
SD Dept. of Environ. & Natural Resources
Division of Environmental Regulation
523 East Capitol
Joe Foss Building
Pierre, SD 57501-3181 605-773-3351
TN UST/LUST CONTACT1
TN Dept. of Environment & Conservation
200 Doctors Building
706 Church Street
Nashville, TN 37243-1541 615-741-4081
TX UST/LUST CONTACT1
- Texas Water Commission '
Petroleum Storage Tank Division
P.O. Box 13087, Capitol Station
1700 North Congress
Austin, TX 78711-3087 512-371-6200
UT UST/LUST CONTACT1 -
UT Dept of Environmental Quality
Bureau of Solid & Hazardous Waste
- Division of Environmental Response and
Remediation
1950 West North Temple
Salt Lake City, UT 84116 801-538-4100
VA UST/LUST CONTACT
VA State Water Control Board
P.O. Box 11143
Richmond, VA 23230-1143
UST: 804-527-5192
LUST: 804-527-5188
VT UST/LUST CONTACT1
VT Dept of Natural Resources
Underground Storage Tank Program
103 South Main Street, West Building
Waterbury, VT 05676-0404
802-244-8702
WA UST CONTACT
WA Department of Ecology
P.O. Box 47655
Olympia, WA 98504-7655 206-459-
LUST CONTACT
WA Department of Ecology
P.O. Box 47600
Olympia. WA 98504-7600 206-438-7164
Wl UST CONTACT
- Wl Dept. of Industry, Labor & Human
Relations
Bureau of Petroleum Insp. & Fire Protection
P.O. Box 7969
201 East Washington Avenue
Madison. Wl 53702 608-266-7605
LUST CONTACT
Wl Department of Natural Resources
P.O. Box 7921
Madison, Wl 53707-7921 608-267-7560
WV UST/LUST CONTACT2
WV Division of Natural Resources
Waste Management Section
UST/LUST Office
1356 Hansford Street
Charleston, WV 25301 304-348-6371
WY UST/LUST CONTACT1
WY Dept. of Environmental Quality
Water Quality Division
Herschler Building, 4th Floor West
122 West 25th Street
Cheyenne, WY 82002 307-777-7781
1 = State has 1 person serving as both the UST and LUST Contact.
2 - State has 1 UST and 1 LUST Contact; both have the same address and telephone number.
3/92
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State UST/LUST Program Offices
ERRITORIES
AS UST/LUST CONTACT1 :
AS Environmental Protection Agency
Office of the Governor
American Samoa Government
ATTN: UST/LUST Program
> Pago Pago, American Samoa 96799
684-633-2304
CNMI UST/LUST CONTACT1
Division of Environmental Quality
P.O. Box 1304, Dr. Torres Hospital
Commonwealth of Northern Mariana Ids
Saipan, MP 96950 607-234-6984
GU UST/LUST CONTACT1
GU Environmental Protection Agency
IT&E
Harmon Plaza, Complex Unit D-107
130 Rojas Street
Harmon, Guam 96911 671-646-8863
PR UST/LUST CONTACT1
Water Quality Control
Environmental Quality Board
P.O. Box 11488
Commonwealth of Puerto Rico
Santurce, Puerto Rico 00910
809-767-8109
VI UST/LUST CONTACT1
Environmental Protection Division
Dept. of Planning and Natural Resources
Suite 321, Nisky Center
45A Estate Nisky
Charlotte Amalie
St. Thomas, Virgin Islands 00802
809-774-3320
state has 1 person serving as both the LIST and LUST Contact.
2 = State has 1 UST and 1 LUST Contact; both have the same address and telephone number.
3/92
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CHAPTER TWO
UST WALK-THROUGH
This chapter will walk you through an underground storage tank (UST) system, including the tanks,
the piping systems, and the product dispensers. The chapter will also introduce frequently used site
terminology, such as excavation zone and water table. This information will serve as a background for
following chapters on site characteristics and leak detection methods for tanks and piping systems.
Lecture Notes
Instructional Aids
Understanding the different parts of an UST sys-
tem allows you to better evaluate the leak detec-
tion requirements and the various leak detection
methods available. This chapter describes a
typical UST system and each of its major com-
ponents.
I. WHAT IS AN UST?
« Underground Storage Tank (UST) refers to
a system storing petroleum products or
hazardous substances. An UST system for
motor fuel includes the tank(s), piping, and
product dispensers. At least 10 percent of
the combined volume of the tank(s) and
associated piping must be underground for
the system to be considered an UST sys-
tem.
Although multi-tank service station USTs are
among the most common tank systems,
and provide the basis for this course, it is
important to recognize that there are several
other systems, including used oil tanks,
single-tank systems, farm tanks, and tanks
without piping.
« With the following exceptions, underground
tanks must comply with Federal UST regula-
tions:
Farm or residential tanks of 1,100 gal-
lons or less storing motor fuel for non-
commercial purposes;
Tanks storing heating oil for consump-
tive use on the premises where stored;
Tanks holding 110 gallons or less;
Introduce the chapter, describing the material to
be covered as it is mentioned in the introduction.
Slide 1: Chapter Two slides.
Slide 2: Define an UST system, including tank,
piping, and dispenser.
Slides 3 and 3A (graphic and photo): Typical
Retail Gasoline Station. Shows petroleum tanks,
piping, and dispensers.
Note: (<) Draws attention to basic Federal re-
quirements for UST systems. You should note
that State and local requirements may be more
stringent.
Note: This course focuses on the service
station system; however, you should mention
that there are other tank types. Mention those
which may be most common in your area.
Slide 4: Discuss these exceptions to Federal
UST regulations.
Chapter Two, Page 1
-------
Lecture Notes
Instructional Aids
Tanks on or above the floor of under-
ground areas, such as basements or
tunnels;
Septic tanks and systems for collecting
storm water and wastewater;
Flow-through process tanks;
Emergency spill and overfill tanks; and
Surface impoundments, ponds, pits, or
lagoons.
Slide 5: Exceptions to Federal UST regulations.
Chapter Two, Page 2
-------
Lecture Notes
Instructional Aids
II. UST SYSTEM PARTS
A. Tanks
1. Typical retail tanks have a
capacity of 2,000 to 12,000 gal-
lons.
Older tanks typically hold
2,000-6,000 gallons.
Newer tanks generally hold
6,000-12,000 gallons.
2. New tanks are generally con-
structed of cathodically protected
coated steel, fiberglass-reinforced
plastic (FRP), or a steel-fiberglass
composite.
B. Piping
1. Product delivery lines connect the
tanks and product dispensers.
Because delivery lines are
generally installed near the
ground surface and have
many connections, leaks
often come from delivery
lines.
2. Manifolded piping typically refers
to a fueling system in which two
or more dispensers are supplied
with product via a piping system
that is connected to one or more
tanks. Manifolded systems have
multiple connections and are thus
particularly susceptible to piping
failures.
An example of manifolded
piping is a single submer-
sible pump in an UST which
supplies three separate
dispensers.
Slide 6: Use this text slide to discuss charac-
teristics of regulated tanks.
Slide 6A (photo): Most older tanks are unpro-
tected; however, regulations require protection.
Note: There may be some exceptions to the
type of tanks encountered, such as partially
buried tanks, lift tanks, separators, and older
tanks made of concrete. Discuss other tank
types that are found in your State.
Slide 6B (photo): Newer tank types include
cathodically protected coated steel, fiberglass,
and fiberglass reinforced plastic (FRP) and steel
composites.
Slide 6C (photo): Steel - FRP composite.
Slide 6D (photo): Discuss areas of concern for
each type of piping (i.e., where joints commonly
leak and which flex connectors and swing joints
are susceptible to damage).
Chapter Two, Page 3
-------
Lecture Notes
Instructional Aids
5.
Vent pipes are routed from the
tank to the surface as above-
ground vents.
-- Vent pipes allow product
fumes to be vented from the
tank into the atmosphere,
thus reducing the risk of
explosion from volatile fumes
under pressure.
Fill pipes usually connect the
underground tank to an above-
ground fitting where a tank truck
connects its transfer hose.
These pipes are used to fill
the tank with the product.
Remote fills have the poten-
tial to leak.
Vapor recovery lines are pipes
that convey petroleum vapors
back to the tank truck during off-
loading or back to the UST during
dispensing of product. In Stage II
vapor recovery, there will be twice
as much piping in the UST sys-
tem because pipes run from dis-
penser back to tank.
C. Product dispensers
A pumping system draws or
pushes product through the pro-
duct delivery lines to a delivery
hose, which dispenses the pro-
duct.
At retail stations, meters attached
to product dispensers measure
the volume of product dispensed
from the UST system.
Slide 6E (photo): Vent pipes.
Slide 6F (photo): Fill box.
Discuss when remote fills are used. They often
pose special problems because they are
installed as an 'afterthought."
Slide 7: Define vapor recovery lines.
Discuss vapor recovery lines and Stage II, if it is
used in areas of your State.
Chapter Two, Page 4
-------
Lecture Notes
Instructional Aids
D. The site
1. Excavation zone is the entire area
that must be dug up in order to
install an LIST.
2. Backfill is any material used to fill
in the excavation zone after the
tank is in place.
Manufacturers' suggestions
should be followed regard-
ing the proper backfill to be
used (generally, crushed
rock, pea gravel, or sand).
3. Water table is the level where
ground water will rest in porous
soil conditions under normal
atmospheric pressure.
Slide 8: Explain each of these terms and use
the following graphic to point them out.
Slide 9 (graphic): Point out each of the terms
discussed in Slide 8.
Explain that ideally the backfill should meet
specifications, but may in reality be local soil,
contaminated soil, etc. Describe problems you
may have seen that resulted from improper
backfill.
Slide 10 (Review/Wrap Up): This is a repeat of
Slide 1, to be used as a review of what you have
covered. Mention the main topics discussed.
Use this time to answer any questions or to dis-
cuss specific UST systems.
Chapter Two, Page 5
-------
CHAPTER THREE
SITE CHARACTERISTICS
What are the Important site characteristics that should be considered when selecting the proper
leak detection method? This chapter will introduce you to relevant UST system characteristics,
product characteristics, soil conditions, climatic factors, and geologic conditions. An understanding of
these factors will help you assist UST owners and operators in making a more informed decision
about the leak detection methods that can be used with particular UST systems.
Lecture Notes
Instructional Aids
Choosing the appropriate leak detection method
for a particular UST system requires understan-
ding how site characteristics can vary. The basic
factors to consider when selecting a leak detec-
tion method fall into five groups:
I. UST system characteristics;
II. Product characteristics;
III. Soil conditions;
IV. Climatic factors; and
V. Geologic conditions.
Slide 1: Chapter Three slides.
Slide 2: Use this slide to introduce the chapter,
explaining that an understanding of the following
site characteristics will assist the UST staff mem-
ber to work with the owners/operators to deter-
mine the most appropriate leak detection
method for their UST system. Explain that
students will be asked to participate in an exer-
cise at the end of the chapter to review the
material and check for understanding.
Chapter Three, Page 1
-------
Lecture Notes
Instructional Aids
I. UST SYSTEM CHARACTERISTICS
A. Tank age (new vs. existing)
1. New tanks are those installed
after December 23, 1988. Exist-
ing tanks are those installed
before December 23,1988.
2. Leak detection compliance dead-
lines differ for new and existing
tanks.
3. Some leak detection methods can
be used only for 10 years after
installation of a new UST or
upgrade of an existing UST.
4. Some leak detection methods are
better suited for new tanks, while
others easily can be incorporated
into existing tank systems.
B. Tank size
1. Certain leak detection methods
cannot be used with tanks larger
than a specified capacity.
C. Piping system
1. Types of piping systems
Suction piping systems use
a vacuum to draw the pro-
duct from the tank to the
dispenser.
Pressurized piping systems
use a pump at the bottom of
the tank to push the product
to the dispenser.
2. Leak detection requirements for
piping differ based on the type of
piping system used.
Slide 3: This slide is an overview of UST system
characteristics, each of which will be discussed.
Slide 4: There are different compliance dead-
lines for existing tanks - those installed before
December 23,1988, and new tanks - those
installed after December 23, 1988.
Slide 5 (graphic): Phase-in schedule for com-
pliance with Federal UST regulations.
Slide 6: The size of the tank may limit the selec-
tion of leak detection methods involving manual
tank gauging, automatic tank gauging systems,
and some tank tightness tests.
Slide 7: Briefly describe the two types of piping.
These types will be discussed in detail in Chap-
ter Five.
Chapter Three, Page 2
-------
Lecture Notes
Instructional Aids
D. UST system size
1. Number of tanks
Slide 8: Discuss both the numbers of tanks,
and the extent of the site area. These variables
may be important when selecting a leak detec-
tion method.
Some leak detection
methods may be better
suited or less costly than
other methods for systems
with many tanks.
2. Extent of site area
Slide 9: (This slide has been deleted.)
Some leak detection
methods may be more effec-
tive or less costly for UST
systems that cover a large
area.
Chapter Three, Page 3
-------
Lecture Notes
Instructional Aids
II. PRODUCT CHARACTERISTICS
A. Types of stored product
Stored products fall into two general
groups: petroleum products and some
hazardous substances.
1. Petroleum products (major types):
Gasoline and blends;
Diesel fuel;
Aviation fuel;
Kerosene;
Heating oil; and
Used oil.
2. Hazardous substances:
CERCLA (Superfund) hazar-
dous substances are subject
to LIST regulations. For
example, ferric chloride, lead
iodide, and zinc nitrate are
hazardous substances.
CERCLA hazardous sub-
stances require secondary
containment unless it can be
proved that another method
will work. This course does
not equip you to determine if
other methods are sufficient.
RCRA hazardous wastes are
not subject to LIST regula-
tions because they are
under different regulations.
(See 40 CFR Parts 260-270
for hazardous waste regula-
tions.)
Slide 10: Discuss the most common types of
stored products, as well as other products that
workers may encounter. Mention that this
course is geared towards petroleum products;
however, other products may be stored.
Characteristics of the products are discussed
individually below in Section B.
Discuss the hazardous substances that are
stored, and which of these are covered by the
regulations.
Note: It is important to stress to students that
this course is designed to inform them about
leak detection methods, but it will not prepare
them to determine if a method is suitable for
hazardous substances. Secondary containment
with interstitial monitoring is the only method that
is always suitable for hazardous substances.
This will be discussed further in Chapter Four.
Chapter Three, Page 4
-------
Lecture Notes
Instructional Aids
B. Characteristics of stored products
Traits of different products may render
certain leak detection methods inap-
propriate. Important characteristics
include:
Solubility;
Density;
Viscosity;
-- Volatility;
Thermal effects; and
Compatibility with tank and piping
materials.
1. Solubility
Solubility is the ability of a
substance to dissolve in or
mix with another substance.
For example, alcohol mixes
more easily with water than
oil does.
This characteristic is impor-
tant to know because if the
product mixes easily with
water, some methods may
not easily be able to detect
its presence (for example,
ground-water monitoring).
2. Density
Density refers to the mass of
a given substance per unit
volume.
If the density of the product
is higher than that of water,
the product may sink
beneath the ground-water
surface and is not easily
detectable. Therefore,
ground-water monitoring is
not allowed for these sub-
stances.
Slide 11: Product characteristics.
Slide 12: Define solubility. Use examples to
help clarify. For example, alcohol in water is
soluble; oil in water is much less soluble.
Slide 13: Define density. The density of a
material will determine whether it floats or sinks.
Slide 14: Gasoline floats on ground water;
dense non-aqueous phase liquids (DNAPLs) do
not.
Chapter Three, Page 5
-------
Lecture Notes
Instructional Aids
3. Viscosity
Viscosity is a measurement
of the ease with which a
liquid flows (for example,
molasses vs. water).
The degree of viscosity
varies with changes in
temperature.
A product's viscosity may
affect which method is suit-
able (for example, whether
tank testing can be con-
ducted, ground-water moni-
toring is effective, automatic
tank gauging can be used).
4. Volatility
Volatility refers to how
readily a substance will
vaporize.
Volatility of the product may
affect the use of certain leak
detection methods. For
example, a product must
vaporize easily if it is to be
detected in vapor monitoring
wells.
5. Thermal effects
Thermal effects refer to
changes in product charac-
teristics that occur in
response to an increase or
decrease in temperature.
Density, viscosity, and
volatility are product charac-
teristics that are affected by
temperature.
For example, lower tempera-
tures reduce the volatility of
a product. As a result,
vapor monitoring can be
affected at sites storing a
product that does not
vaporize well at low temper-
atures.
Slide 15: Define viscosity. Tell students to
imagine water flowing vs. molasses flowing.
Slide 16: Define volatility. Certain materials
evaporate much easier than others. Use gaso-
line vs. heating oil to clarify.
Slide 17: Thermal effects are of particular con-
cern in areas of extreme temperatures, or areas
that experience large temperature variations.
Discuss how other characteristics change with
temperature.
Chapter Three, Page 6
-------
Lecture Notes
Instructional Aids
Temperature changes can
affect the volume of a pro-
duct. Monitoring methods
that measure volume need
to account for changes in
volume created by tempera-
ture changes.
6. Compatibility
Compatibility refers to the
chemical effects stored pro-
ducts may have on tank
materials.
Certain fuel blends (metha-
nol and ethanol) and
hazardous substances may
not be compatible with the
tank and piping material or
tank lining, causing them to
degrade.
A tank owner storing these
materials should check with
the manufacturer to ensure
that they are compatible with
the tank and piping.
Chapter Three, Page 7
-------
Lecture Notes
Instructional Aids
III. SOIL CONDITIONS: BACKFILL &
SURROUNDING SOIL
A. Relative porosity
1. Relative porosity refers to a
measurement of the extent to
which a material (for example, soil
or backfill) contains small spaces
through which vapors or liquids
can pass.
2. Higher porosity backfill materials
allow product vapors and liquids
to pass through with greater
ease.
3. Methods that monitor the environ-
ment around the tank for signs of
the leaked product require higher
porosity backfills. New backfill
that meets codes would meet
porosity requirements. Older
backfill needs to be tested for
porosity to gauge whether
porosity is sufficient for external
methods to detect leaks quickly.
B. Hydraulic conductivity
1. Hydraulic conductivity refers to a
measurement of the rate at which
a liquid (for example, water) can
flow through a material such as
soil.
2. Some materials can have high
porosities but low hydraulic con-
ductivity; thus, both measure-
ments should be considered.
3. The presence of backfill materials
with low hydraulic conductivity
(for example, clay) generally pre-
cludes the use of leak detection
methods that monitor the environ-
ment around the tank and piping.
Slide 18: There are three soil characteristics
that we will discuss: porosity, hydraulic conduc-
tivity, and contamination.
Slide 19: Define porosity. .
Slide 20 (graphic): This graph shows the effect
of soil conditions (porosity and moisture) on
vapor concentrations. Note that the readings
were taken the same distance from the free pro-
duct, at the same time. A low porosity, high
moisture soil can mask the vapors detected, so
certain detection methods may require greater
well spacing.
Slide 21: Define hydraulic conductivity. Explain
that this and porosity need to be considered. It
is possible to have a high porosity with low con-
ductivity. (The pores may be large, but not con-
nected, so fluid cannot travel through.)
For example, clay has significant void space
(high porosity), but low conductivity.
Conductivity may also be affected by karst
topography or utility conduits.
Chapter Three, Page 8
-------
Lecture Notes
Instructional Aids
C. Contamination
1. Soil or backfill may be con-
taminated by past releases (for
example, leaks, spills, or overfills).
2. Some methods of leak detection
would sense this past con-
tamination and inaccurately signal
a current leak.
Slide 22: Mention problems that can occur due
to previously contaminated soil or backfill. Tests
may incorrectly indicate a leak even when there
is no problem with the UST system.
Review soil conditions. Answer questions.
Chapter Three, Page 9
-------
Lecture Notes
Instructional Aids
IV. CLIMATIC FACTORS
A. Temperature
1. Extreme temperatures or dramatic
changes in temperature may
affect the accuracy of certain leak
detection methods, and may
render other methods ineffective.
Slide 23: Both temperature and amount of rain-
fall may affect results obtained by certain leak
detection methods. Discuss how these factors
may be a problem in your State.
B. Rainfall
1. Sites subject to heavy rainfall may
experience significant changes in
ground-water levels.
Fluctuating ground-water
levels may affect the
accuracy of ground-water
monitoring, and vapor
monitoring.
Chapter Three, Page 10
-------
Lecture Notes
Instructional Aids
V. GEOLOGIC CONDITIONS
A. Effects of ground water
1. The level of ground water relative
to the tank's product level and
the location of the 'hole" can
affect both the rate and direction
of a leak. If ground water is high-
er than the product level inside a
tank, ground water will generally
flow into the tank. If the product
level is higher than the ground-
water level, the product will gen-
erally flow out of the tank. By
influencing both the rate and
direction of a leak, the level and
density of ground water relative to
the level and density of the pro-
duct in a tank can mask a leak.
To detect leaks in this situation,
monitoring devices need to be
used that can detect water in the
tank.
B. Important ground-water variables
1. Depth of water table
The water table depth may
affect the accuracy of vapor
and ground-water monitor-
ing.
2. Large fluctuations in the water
table levels affect the accuracy of
vapor and ground-water monitor-
ing methods.
3. Gradient of ground-water flow
If the gradient is steep, and
the monitoring wells are not
properly placed, ground-
water flow may bypass the
monitoring wells and the
release may not be
detected.
Slide 24: There are also ground-water con-
ditions to consider.
Slide 25: Discuss how the presence of ground
water can mask a leak.
Slide 26 (graphic): Use this diagram to explain
how ground water can slow a leak by exerting
pressure on the tank, or increase the volume by
seeping into the tank.
Slide 27: The depth and gradient of the water
table may influence the leak detection method
used. Stress problems that this causes in your
area, especially in areas of a fluctuating water
table (e.g., tidal areas).
Explain that with a steep gradient, the free pro-
duct may flow in a single, narrow path, thus
missing a well. With a gentle gradient, the pro-
duct may flow slower and spread out more hori-
zontally, thus having a greater chance of being
detected by the well. (Have students envision
water flowing down a steeply versus a slightly
sloped pane of glass.)
Chapter Three, Page 11
-------
Lecture Notes
Instructional Aids
Slide 28: Use this slide as a review to show
what material has been covered in the chapter.
Ask if there are any questions or specific char-
acteristics that they wish to discuss further.
Hand out the exercise on UST Site Characteris-
tics from Appendix II. Have students work either
individually or in small groups. Allow 10-15
minutes (or more if necessary). Then go over
the questions with students in a group. Make
sure that any State-specific questions that might
be helpful are covered. A sample list of ques-
tions also is included in Appendix II.
Chapter Three, Page 12
-------
CHAPTER FOUR
LEAK DETECTION METHODS FOR TANKS
How can you assist the owner or operator to select the right leak detection method for a specific
UST? This chapter describes several methods that meet the Federal requirements for leak detection.
This chapter's descriptions, considerations, and limitations noted for each system can help you assist
owners and operators in choosing the best leak detection system for their particular facilities. The
chapter is divided into three parts: Part I notes some general leak detection requirements, Part II deals
with monthly monitoring methods, and Part III treats the temporary leak detection method of tank
tightness testing and inventory control.
Lecture Notes
Instructional Aids
GENERAL LEAK DETECTION
REQUIREMENTS
A. Deadlines
1. New tanks
Tanks installed after Decem-
ber 23,1988, must comply
with UST leak detection
requirements when
Installed.
2. Existing tanks
Tanks installed before
December 23,1988, must
comply with UST leak detec-
tion requirements according
to the following timetable:
Installation
Date
Must Compty
By
Before 1965
1966 -1969
1970-1974
1975 - 1979
1980-1988
December 1989
December 1990
December 1991
December 1992
December 1993
Or if installation date is unknown.
Slide 1: Chapter Four slides.
Slide 2: Use this slide to introduce the chapter.
Mention that each method will be discussed in
detail in the chapter, including how it works, its
applicability, and special considerations.
Slide 2A (graphic photo): Leak detection alter-
natives.
Slide 3: Remind students that deadlines will
have to be met according to the date of tank
installation. A 'new tank is one installed after
December 1988.
Note: Remind students that the (<) represents
basic Federal regulations.
Slide 4: Review compliance dates.
Chapter Four, Page 1
-------
Lecture Notes
Instructional Aids
B. Leak detection methods allowed
1. New tanks require one of the following:
Monthly monitoring; or
Monthly inventory control with tank tightness
testing every five years. This option can be
used only for ten years after installation.
2. Existing tanks require one of the following:
Monthly monitoring; or
Monthly inventory control and annual tank
tightness testing. This option can be used
only until December 1998; or
Monthly inventory control and tank tightness
testing every five years. This option can be
used only for ten years after a tank has
been upgraded with spill/overflow
prevention devices and corrosion protection.
C. Requirements for probability of
detection/probability of false alarm (PO/
PFA)
1. Some leak detection methods (tank or
piping tightness testing, automatic tank
gauging systems, statistical inventory
reconciliation, and automatic line leak
detectors) must be capable of detecting
the leak rate or quantity specified for that
method with a probability of detection (PD)
of 0.95 and a probability of false alarm
(PFA) of 0.05.
There are two PD/PFA compliance
deadlines:
By December1! 990, automatic tank
gauging systems, statistical inventory
reconciliation, and tightness tests for tanks
or piping must meet PD/PFA
requirements;
By September 1991, automatic line leak
detectors must meet PD/PFA requirements.
Slides 5 and 6: Discuss new tank require-
ments. Point out the differences between
new tank requirements and those for existing
tanks.
Note that monthly inventory control with tank
tightness testing can be used only for ten
years after installation or upgrade (or until
December 1998 for tanks without upgrade).
Slide 7: Discuss PD/PFA "95 and 5"
requirements.
Chapter Four, Page 2
-------
Lecture Notes
Instructional Aids
However, methods permanently installed
before the applicable compliance deadline
are not required to meet the PD/PFA
requirements.
D. Standard test procedures
EPA has developed standard test
procedures (also known as protocols) that
enable manufacturers of release detection
methods and third-party evaluators of those
methods to demonstrate that the methods
can meet the Federal release detection
requirements. Results form these highly
technical testing procedures can be
summarized on a short form provided with
each test procedure. Having summarized
^-test results, -manufacturers can distribute the
forms to tank owners and State and local
regulators, who can use them to verify that
the method being described meets EPA's
release detection standards.
As of January 1992, EPA has published
seven standard test procedures:
Volumetric tank tightness test methods;
Non-volumentric tank tightness test
methods;
Automatic tank gauging systems;
Liquid-phase out-of-tank product detectors;
Vapor-phase out-of-tank product detectors;
Statistical inventory reconciliation methods;
and
Pipeline leak detection systems.
Your course instructor can tell you more
about these published standard test
procedures and how to get copies of them.
Chapter Four, Page 3
-------
Lecture Notes
Instructional Aids
II. LEAK DETECTION METHODS: MONTHLY
MONITORING
Federal regulations describe five acceptable
monthly monitoring methods:
Automatic tank gauging systems;
Manual tank gauging;
Secondary containment with interstitial
monitoring;
Ground-water monitoring; and
Vapor monitoring.
The following sections briefly describe each
method, discuss the conditions suitable for
a method's application, and point out the
major factors owners and operators should
consider when selecting a method.
A. Automatic tank gauging systems
(ATGS)
1. How ATGS work
Automatic tank gauging systems con-
tinuously measure and record product
level and temperature within the tank
to determine the change in volume
over time. If there is a significant loss
of volume, then there may be a leak.
Each tank is equipped with a
probe to measure product level
and temperature.
Underground wiring connects the
tank with a monitor and micropro-
cessor to record data read by
probe:
Product level;
Water level; and
Temperature.
Slide 8: Each of these methods will be
discussed in this chapter.
Note: Place emphasis on the methods that are
most commonly used in your area.
Note: Remind students that these methods are
conducted at least monthly.
Slide 9: Each method is discussed within the
following structure: how the method works;
when the method is appropriate; and con-
siderations for owners/operators.
Slide 9A (graphic photo): ATGS introduction.
Slide 10: The first method is ATGS.
ATGS continuously measure product level, water
level, and temperature in the tank.
Slide 10A (graphic photo): Facility layout show-
ing ATGS.
The sensors continuously measure the product
in the tank. If there is a significant loss of
volume that cannot be accounted for due to
temperature change, a leak may be indicated.
Slide 11 (graphic): Use this graphic to point
out the various parts of an ATGS. Point out that
the probe is inside the tank.
Slide 11A (photo): ATGS probe installed into a
tank.
Slide 11B (photo): ATGS remote monitor. Point
out readings that can be obtained from the mon-
itor.
Slide 11C (photo): ATGS remote monitor.
Chapter Four, Page 4
-------
Lecture Notes
Instructional Aids
A leak is indicated if recorded
temperature changes cannot
account for the measured volume
change.
ATGS must be able to detect 0.2
gal/h release from any portion of
the tank that routinely contains
product.
ATGS have two modes, and the
same equipment performs both
operations:
Inventory control; and
Leak testing.
a. Inventory control mode
This mode automatically
records activities of an
in-service tank, including
deliveries.
Product level and tem-
perature readings are
taken automatically and
computer converts
them to volume meas-
urements.
ATGS operate in this
mode whenever leak
test mode is not being
performed.
In most systems, a probe
measures water levels in the
bottom of the tank and con-
verts to a volume, which is
used in inventory control.
The probe can also indicate
a leak of ground water into
the tank.
For most ATGS, on-site staff
must manually record
dispenser information.
Slide 12: There are two modes of operation of
an ATGS.
Slide 13 (graphic): Based on this flow chart,
discuss activities and procedures for setting up,
monitoring, and analyzing data with an ATGS.
Slide 14: Discuss how an ATGS works; that the
tank has a dedicated opening for the ATGS and
measurements are automatically taken and con-
verted into volume.
Mention that these are typical characteristics of
ATGS, and that systems will vary according to
manufacturer.
Chapter Four, Page 5
-------
Lecture Notes
Instructional Aids
2.
Many systems have alarms
to alert on-site staff of:
High and low product
levels;
High water levels inside
tank; and
Theft.
b. Leak testing mode
Product level and tempera-
ture are measured generally
at least two hours a month
in out-of-service tanks, usu-
ally at night. The test can
be set to last a given length
of time.
The frequency of meas-
urements and length of
test is determined by
the manufacturer to
meet PD/PFA require-
ments and the regula-
tory performance stan-
dard of 0.2 gal/hr, and
are programmed into
ATGS. Generally, the
longer the test is con-
ducted, the higher the
performance level of
the test.
Test can be run with
any level of product in
the tank.
The temperature and
product level readings
are taken automatically.
When automatic tank gauging
systems are appropriate
a. UST system characteristics
ATGS are used primarily on
tanks smaller than 15,000
gallons.
Slide 15: Discuss ATGS Alarm Systems.
Slide 16: Discuss how the leak testing mode
works. The longer the test is conducted, the
more accurate the results will be.
Slides 17 and 18:
appropriate.
Discuss when ATGS are
Chapter Four, Page 6
-------
Lecture Notes
Instructional Aids
ATGS cannot be used for
piping.
b. Product characteristics
To date ATGS used mostly
with gasoline or diesel tanks
because service stations
have been the primary
ATGS users.
If other products are to be
tested, owner/operator
should ascertain that ATGS
meets regulatory per-
formance standards when
used with that product.
c. Soil conditions
Use of ATGS is not
restricted by soil type.
d. Climatic factors
Wait at least six hours
between delivery and testing
to stabilize temperature dif-
ferences between added
product and product already
in tank. The wait time may
vary due to climate.
e. Geologic conditions
If the ground water is high
enough to cover a hole in a
leaking tank, a leak may be
masked and water may
enter the tank.
Therefore, ATGS should
have water sensors with
alarms, so that they can
monitor for an increase in
water as well as a decrease
in the level of product.
Note: For each leak detection method the dis-
cussion will go through each of the site charac-
teristics from Chapter Three.
Slide 19 (graphic): This graphic helps explain
why at least a six-hour waiting period is neces-
sary. Newly added product causes chaos within
the normal tank product stratification (layering).
Once the product has re-stratified, tests can be
conducted, achieving more accurate results.
The left side of the graph represents tempera-
ture. The horizontal axis represents the number
of hours. Note how the temperature layers "calm
down."
Slide 20 (graphic): Use this graphic to explain
how changing levels in ground water can affect
test results. High ground water can mask a leak
or allow water into the tank.
Slide 20A (graphic photo): Sample results from
an ATGS.
Chapter Four, Page 7
-------
Lecture Notes
Instructional Aids
3. Considerations
No product should be
delivered to the tank for at
least six hours before the
monthly test, to allow the
temperature to stabilize.
No withdrawal should be
made from the tank for a few
hours prior to testing. With-
drawals disturb the stratified
layers in the tank, which can
lead to inaccurate test
results.
No product withdrawals or
deliveries can be made
during the monthly test
which lasts one to six hours
or more, depending on the
manufacturers' recommen-
dation.
ATGS automation reduces
time that employees must
spend in monitoring leak
detection.
Inventory control and poten-
tial off-site monitoring
features are attractive to
some owners and operators.
Tanks require a dedicated
opening for the ATGS
probe, making retrofit dif-
ficult in some cases.
B. Manual tank gauging (MTG)
1. How MTG works
MTG is a short-term test in a
static (i.e., closed) tank. It cannot
be used for tanks larger than
2,000 gallons.
a. It differs from inventory con-
trol, which requires daily
recording of volume in an
active tank, and keeping
track of additions and with-
drawals.
Slides 21 and 22: Discuss the other considera-
tions for the use of ATGS.
Hand out exercise on ATGS from Appendix II.
Discuss as a group once students have had the
opportunity to work through the problem.
Slide 23: Note that MTG can be used only on
small tanks (under 2001 gallons). Describe MTG
and explain that this method must be conducted
in a static tank, and must last 36 to 58 hours,
depending on the size of the tank.
Chapter Four, Page 8
-------
Lecture Notes
Instructional Aids
b. With MTG, weekly measure-
ments of product levels are
taken with a gauge stick
inserted in the tank through
the fill pipe.
c. A test is conducted once
each week and lasts at least
36 hours.
d. The UST must not be in use
between measurements (no
product can be added or
withdrawn during this test
period).
e. Four measurements must be
taken:
Two at beginning of the
weekly test; and
Two at end of the weekly
test.
f. A calibration chart specific
to the tank is used to con-
vert product level measure-
ment into product volume.
g. The average of the final two
measurements is subtracted
from the average of the first
two to obtain the change in
product volume over time.
h. The calculated product
volume change is compared
to weekly and monthly stan-
dards (below, in gallons). If
the volume change exceeds
these standards, the tank
may be leaking. (The
monthly figure is a simple
average of the weekly
measurements.)
Slide 23A (photo): Person using a gauge stick.
Slide 24: Discuss each requirement for MTG.
Emphasize those required by the regulations.
Slide 25 (graphic): Enlarged sample calibration
chart. Point out the depth (in inches), tank
capacity, and how to find the product volume.
Emphasize that the owner/operator should have
the calibration chart for his or her tank from the
tank's manufacturer.
Slide 26: Discuss how MTG works.
Slide 27: Discuss the chart of weekly and
monthly standards for volume change.
Chapter Four, Page 9
-------
Lecture Notes
Instructional Aids
Tank
Capacity
faaU
Weekly Monthly Test
Change Change Duration
faat.) taal.) fhrs.i
Up to 550 10 5 36
55M ,000{64'x73") 9 4 44
1,000(48'X128") 12 6 58
If MTG is combined with TTT:
1,001 - 2,000 26 13 36
2. When MTG is appropriate
a. UST system characteristics
Only tanks of 1,000 gallons
or less can use MTG as the
only leak detection method
for the life of the tank.
Tanks between 1,001 and
2,000 gallons must combine
MTG with tank tightness
testing. This combined
method can be used only
for ten years following new
tank installation or upgrade
of existing USTs. Tank tight-
ness tests must be per-
formed annually for existing,
non-upgraded USTs, and
every five years for up-
graded and new USTs.
(USTs that have not been
upgraded cannot use this
combined method after
December 1998.)
- Tanks larger than 2,000
gallons cannot use MTG.
MTG cannot be used for
piping.
b. Product characteristics
Not restricted to particular
fuel types.
Slide 28: Discuss tank size and the restrictions
that apply.
Slide 29: This method is not restricted to fuel
types. However, a heavier fuel, such as used oil,
will be easier to measure. (Imagine using a dip
stick to measure alcohol vs. measuring used oil.
The alcohol level would be difficult to read due
to evaporation.)
Chapter Four, Page 10
-------
Lecture Notes
Instructional Aids
Works best with heavier
fluids (such as used oil and
diesel) because they don't
evaporate easily, are less
sensitive to temperature
changes, and can be seen
more easily on the gauge
stick.
c. Soil conditions
Use is not restricted by soil
type.
d. Climatic factors
Ambient (surrounding)
temperature changes may
affect volume of stored pro-
duct due to expansion and
contraction of liquid. This is
one of the reasons the test
must last so long.
If temperature change is
great, the testing period can
be lengthened so that the
beginning and ending
gauge measurements can
be taken at the same time of
day.
Because this method does
not account for temperature
change, false alarms may
occur in areas of extreme
temperature variation.
e. Geologic conditions
If the ground water is higher
than product level in a
leaking tank, it can exert
pressure that can hide a
leak from MTG.
Permanently high ground
water may render this
method inappropriate.
Slide 30: Mention that the testing period can be
extended so that the tests are conducted at the
same time of day. This may be important in
areas where the temperature varies greatly
between day and night.
Slide 31: Once again, ground water may mask
a leak.
Chapter Four, Page 11
-------
Lecture Notes
Instructional Aids
C.
3. Considerations
UST system must be
removed from service at
least 36 hours every week.
Equipment costs are very
low.
Secondary containment with
Interstitial monitoring
1. How secondary containment with
interstitial monitoring works
Secondary containment involves
placing a barrier between the tank and
its surrounding environment. The bar-
rier may fully or only partially enclose
the UST. Leaks are contained in the
space between the tank and its
secondary barrier. In addition, inter-
stitial monitoring systems test for pres-
ence of released product in the space
(interstice) between the tank and its
outer containment barrier.
a. Secondary containment may
include:
Concrete vault;
Double-walled tank;
Tank with excavation liner;
and
Internal bladder.
Slide 32: Tanks must be taken out of service for
at least 36 hours a week.
Answer any questions pertaining to MTG.
Slide 32A (graphic photo): Interstitial monitor-
ing.
Slide 33: Discuss how secondary containment
provides a barrier between the tank and the
surrounding environment. The interstitial monitor
tests for leaks in the space between the tank
and the barrier.
Slide 34 (graphic): Shows tanks within a con-
crete vault. They are on supports, as shown,
with or without backfill. Notice the sump
installed for detecting leaks.
Slide 35 (graphic): Shows double-walled tanks.
Slide 36 (graphic): Shows a diagram of a tank
with a liner installed.
Slide 36A (photo): Excavation liner.
Slide 36B (photo): Spread out liner.
Slide 36C (photo): Tank and observation wells
installed.
Slide 36D (photo): Backfill.
Slide 36E (photo): Internal bladder.
Slide 36F (photo): Internal bladder installed in
tank.
Slide 36G (photo): Interstitial space monitor for
internal bladder.
Chapter Four, Page 12
-------
Lecture Notes
Instructional Aids
b. Fully enclosed systems
include:
Concrete vaults,
Double-walled tanks, and
Internal bladders.
c. Partially enclosed systems
may include:
Excavation liners.
In areas of heavy rainfall,
liners should fully enclose
the tank to prevent rainwater
from sitting in the backfill
and interfering with the mon-
itoring equipment.
d. Interstitial monitoring
methods include:
Electrical conductivity
methods monitor changes in
conductivity by differentiat-
ing between petroleum (non-
polar) and water (polar).
Pressure sensing methods
apply either vacuum or pres-
sure to the interstitial space.
A leak is detected by chang-
es in pressure.
Liquid sensors detect the
presence of a liquid by use
of coated fibers or other
materials that respond pre-
ferentially to liquid in the
tank. Alternatively, there
may be a pressure switch at
the bottom of the interstitial
space.
Hydrostatic sensors monitor
changes in the level of liquid
in the interstitial space.
Manual detection methods
use product-finding paste on
a dipstick to find liquid pro-
duct in the interstitial space.
Slide 37: Discuss each monitoring method.
Which are most common in your State?
Slide 38 (graphic): Shows where sensors for
two types of interstitial monitoring are placed.
Mention that the system would normally use only
either vapor or liquid sensors, not both.
Chapter Four, Page 13
-------
Lecture Notes
Instructional Aids
Vapor monitoring checks for
presence of product fumes
in the interstitial space.
2. When secondary containment
with interstitial monitoring is
appropriate
a. UST system characteristics
This method can be used
for both tanks and piping.
Containment system for
piping involves placing
liner underneath or
around piping to
establish interstitial
space, assembling a
pipe within a larger
diameter pipe, and
double-walled piping.
Double-walled tanks are
seldom larger than 20,000
gallons.
Larger tanks are very
heavy and difficult to
ship.
Excavation liners may be
used around any size tank.
Secondary containment is
impractical for existing tanks
and piping, except when
internal bladders are
available for existing tanks.
Installation for existing
tanks and piping
requires substantial
retrofitting.
b. Product characteristics
Use of this method is un-
restricted for all fuel types.
c. Soil conditions
Use of this method is not
restricted by soil type.
Slide 39: Discuss each point on the slide.
Slide 40: Note that this is the only method that
can always be used for hazardous substances,
as long as interstitial monitoring is appropriate
for the stored substance. Other methods can be
used with hazardous substances if the manufac-
turer can demonstrate that the method is effec-
tive. This course does not prepare the student
to determine if the other methods are
appropriate for specific hazardous substances.
Chapter Four, Page 14
-------
Lecture Notes
Instructional Aids
d. Climatic factors
This method can be used in
all climatic conditions. How-
ever, in areas with heavy
rainfall, a barrier system
which fully encloses the tank
should be used to prevent
rain from interfering with the
monitoring system. A tank
liner that only partially
encloses the tank may
collect water, and therefore
is not appropriate.
e. Geologic conditions
Tanks located in areas with
high ground water should
use a fully enclosed contain-
ment system.
3. Considerations
a. Installation of secondary
containment using liners
requires even more careful
attention by professional
installers than other leak
detection methods.
b. Containment barrier used
must be compatible with
product stored.
Exposure to product should
not result in deterioration of
barrier, which would release
product into the environ-
ment.
For standard petroleum
products, such as gasoline
and diesel fuel, most liners
sold by reputable firms are
compatible with product.
For other products, nature of
product and type of barrier
must be considered to en-
sure an appropriate match.
Slide 41: Areas where there is high annual
rainfall or a high water table will need to install
fully enclosed containment systems to prevent
water from interfering with the monitoring
system.
Slides 42, 43, and 44: Discuss other points to
consider when using secondary containment
with interstitial monitoring. What are other con-
siderations or problems that you have
encountered?
Chapter Four, Page 15
-------
Lecture Notes
Instructional Aids
c. If a leak occurs, the barrier
provides a degree of protec-
tion for surrounding environ-
ment against exposure.
This aspect differentiates
this method from others,
which detect leaks but do
not contain them.
Lower corrective action
costs associated with this
method than with other leak
detection methods.
D. Ground-water monitoring
1. How ground-water monitoring
works
Ground-water monitoring detects free
product in monitoring wells. The moni-
toring wells extend from the ground
surface to several feet below the low-
est water table level. The leaked
product travels through the soil and
reaches ground-water wells and
detection equipment.
a. Monitoring wells
Generally one to four wells
per UST system will
adequately detect leaks.
Wells must be placed in, or
near, backfill so that they
can detect leaks rapidly.
To intercept free product the
well screen must extend
from the bottom of well to
the highest point of the
water table surface.
On-site staff must check
wells at least monthly for
presence of free product.
Slide 44A (graphic photo): Introduction to
ground-water monitoring.
Slide 45: Discuss structure of ground-water
monitoring wells and how ground-water moni-
toring works.
Slide 46 (graphic): Shows components of a
typical ground-water monitoring well.
Note: It may be beneficial to bring in sections of
screening and other well materials.
Slide 47 (graphic): Shows placement of a mon-
itoring well, and how it will detect free product.
Slide 48 (graphic): Shows that the screen must
cover the entire range of ground-water
fluctuation.
Chapter Four, Page 16
-------
Lecture Notes
Instructional Aids
b. Manual devices for detecting
free product
Grab samplers (bailers or
buckets) collect liquid
samples for visual inspection
or on-site electronic
analysis.
Chemical-sensitive pastes,
attached to a weighted tape
measure, are lowered into
the well and change color
when hydrocarbons are
present.
Manual devices must be
used at least once a month.
Additional measurements
need to be taken during the
month.
Manual devices need to be
able to detect 1/8 inch of
free product.
c. Automatic devices for
detecting free product
These devices need to be
able to detect 1/8 inch of
free product.
Differential float devices
contain two floats:
One float reacts only to
liquids with density
similar to water.
One float responds
only to liquids lighter
than water.
Different float levels will
trigger an alarm.
Product soluble devices:
These devices are
coated with material
that degrades when
exposed to hydro-
carbons.
Slide 49: Discuss manual sample collection,
such as use of bailers, and automated systems.
Slide 50: Bring in examples of bailers and
paste, if possible.
Slide 50A (photo): Person using bailer.
Slide SOB (photo): Person using bailer.
Slide 50C (photo): Drop stick with paste.
Slide 51:
work.
Describe how these detection devices
Slide 52 (graphic): Shows cross-section of
differential float devices. Note that graphic illus-
trates a monitoring well contaminated by a con-
siderable amount of product.
Slide 53 (graphic):
soluble device.
Cross-section of product-
Chapter Four, Page 17
-------
Lecture Notes
Instructional Aids
2.
Thermal conductivity
devices:
These devices measure
heat loss when a
floating probe contacts
certain liquids.
Electrical conductivity
devices:
These devices measure
changes in electrical
resistance that trigger
alarms.
Automatic monitoring
devices must be operated at
least once a month.
Automatic monitoring
devices are either per-
manently installed or placed
in the well during each test.
When ground-water monitoring is
appropriate
a. UST system characteristics
This method can be used to
detect leaks from tanks and
piping.
This method may be used
on any size tank. For larger
systems, more wells are
added.
This method may be retro-
fitted, but installer must be
careful not to puncture tanks
or piping.
b. Product characteristics
~ Product density must be
lower than that of water.
(Product must float on top of
water.)
Slide 54 (graphic): Cross-section of thermal
conductivity device.
Slide 55: Discuss these and other factors that
could affect applicability.
Slide 56: Product characteristics.
Chapter Four, Page 18
-------
Lecture Notes
Instructional Aids
The product should not mix
easily with water. (If it
mixes, no free product layer
will form.)
This method is most com-
monly used for gasoline and
diesel fuels. (Alcohols and
water-soluble chemicals are
not appropriate.)
c. Soil conditions
If this method is used alone,
soil and backfill material
between well and LIST must
be coarse and permeable
(for example, sand or gravel)
to allow released product to
travel to wells.
Hydraulic conductivity of
backfill material and soil
between tank and moni-
toring well should be more
than 0.01 cm/sec.
If national codes are fol-
lowed for installation, the
above requirements and
conditions will have been
met.
d. Climatic factors
Very low temperatures may
interfere with some moni-
toring devices. Ice can
freeze monitors and interfere
with product-soluble
devices.
e. Geologic conditions
Level of ground-water table
If this method is used
alone, ground water
must not be more than
20 feet below the
surface.
Note: Product must be a floater" vs. a 'sinker,'
i.e., must not mix readily with water. Method is
most commonly used with gasoline and diesel
fuels.
Slide 57: Explain the terms 'porosity' and
hydraulic conductivity." (Review from Chapter
Three)
Slide 57A (photo): Drilling.
Slide 57B (photo): Taking a soil core sample.
Slide 57C (photo): Workers installing backfill.
Slide 58: Discuss climatic problems relating to
ground-water monitoring as they pertain to your
State (e.g., high annual rainfall, low rainfall or
extreme temperatures).
Slide 59: Discuss these requirements.
Chapter Four, Page 19
-------
Lecture Notes
Instructional Aids
Ideally, the ground
water should be
between 2 and 10 feet
from the surface.
Fluctuations in water table
level
If water level falls below
or rises above the well
screen, this method
alone becomes insuffi-
cient to detect released
product.
Gradient of ground-water
flow
If the gradient is steep,
the product may by-
pass the monitoring
wells. The most com-
plete coverage would
have wells installed on
all sides of the site to
intercept product and
ensure release detec-
tion.
Fractures and cavities
Because free product
tends to flow through
fractures and cavities in
the soil, wells that do
not intercept these
fractures and cavities
will not detect free
product.
3. Considerations
a. Site assessment is required
before installation. This
involves:
Identification of soil type,
ground-water depth and flow
direction, and general
geology of site.
Mention that it is essential to know the water
table level and gradient in order to have an
effective ground-water monitoring program.
Note: Describe liquid flowing down a steep hill
vs. a gentle hill. The steep grade will cause the
liquid to travel in a narrow path, vs. a gentle
slope where the liquid might spread out more.
Similarly, a steep gradient may mean that the
release may flow past the well without being
detected.
Slide 60 (graphic): This graphic shows how the
well can be installed in a seemingly good place,
but due to the geology, will still not detect a
release.
Slide 61: Discuss these considerations, and
any others you may have. Is ground-water
monitoring used frequently in your State? What
specific problems prevent the use of ground-
water monitoring?
Chapter Four, Page 20
-------
Lecture Notes
Instructional Aids
Identification of evidence of
previous leaks that would
falsely indicate a current
release.
b. Simple operation of
detection devices.
On-site staff must take
samples at least once a
month.
c. When installing monitoring
wells, it is essential to avoid
puncturing tanks or piping
for UST or utility lines (such
as gas, sewer, water, and
electric).
E. Vapor monitoring systems
1. How vapor monitoring works
Vapor monitoring systems check for
presence of product fumes in the soil
or backfill around tank. After a leaked
material evaporates, its vapors travel
through porous soil, and may be
detected by vapor monitoring equip-
ment located in monitoring wells.
a. This method is operated
either automatically or
manually.
Automatic systems incor-
porate a network of sensors
that test for presence of
vapors in monitoring wells.
Manual monitoring systems
collect air samples from
wells surrounding tank to
determine presence of
vapors.
Review ground-water monitoring.
Hand out the ground-water monitoring exercise
from Appendix II. Discuss as a group once stu-
dents have had the opportunity to work through
the problem.
Slide 62: Describe how vapor monitoring
systems work; they monitor for presence of
vapor from product near the UST system. Men-
tion both automatic and manual systems.
Slide 63 (graphic): (This slide has been
removed.)
Slide 64 (graphic): A schematic diagram of an
UST system with vapor monitoring.
Slide 65 (graphic): A map view of an UST sys-
tem with vapor monitoring. Note location of the
three types of vapor wells: background, tank,
and product line vapor wells.
Chapter Four, Page 21
-------
Lecture Notes
Instructional Aids
2. When vapor monitoring is
appropriate
a. UST system characteristics
This method can be used
for both tanks and piping.
This method can be installed
as part of new or existing
tanks and piping.
b. Product characteristics
Vapor monitoring must be
used with products that
vaporize readily. For
example, gasoline, diesel
fuel, and aviation fuels are
appropriate, but fuel oils
No. 4 or No. 6 are not.
c. Soil conditions
The backfill and soil around
the tank must be porous
enough to allow the vapors
to reach the monitoring
wells.
For example, sand and
gravel are porous materials.
Clay is not porous and
should not be used as
backfill.
Backfill and nearby soil must
be clean and should not
contain substances that will
produce vapors.
Previously contaminated soil
may lead to false readings,
indicating releases.
d. Climatic factors
Temperature affects the
volatility of released product.
Sensors may need to be
adjusted for extreme
temperatures.
Slide 65A (graphic photo): Vapor monitoring
system.
Slide 65B (graphic photo): Vapor monitor.
Slide 66: Discuss applicability of vapor
monitoring.
Slide 66A (graphic photo): Vapor monitoring
trends upon start-up.
Slide 66B (graphic photo): Vapor monitoring
detecting a spill.
Slide 66C (graphic photo): Soil Sentry data.
Slide 67: Give examples of fuels that are most
appropriate for vapor monitoring due to their
high volatility (e.g., gasoline).
Slide 68: Discuss how backfills can distort
results, such as previous soil contamination.
Soil type can affect how the vapor can travel.
Slide 69 (graphic): This graph demonstrates
the effects of soil conditions on vapor con-
centrations at a vapor monitoring well. The ver-
tical axis is gasoline in ppm, the hon'zontal axis
represents time in days. Note that the vapor
concentrations are much lower in wet sand or
clay vs. the dry backfill. These are all readings
taken from the same release, at the same
distance from the source.
Slide 70: Climate.
Chapter Four, Page 22
-------
Lecture Notes
Instructional Aids
This method should not be used in areas
with heavy annual rainfall or extremely
moist climates.
The water fills spaces between the soil
particles, preventing vapor from travelling
through the soil. Vapors may also dissolve
in the mositure before reaching the
monitors.
Heavy rains may fill monitoring wells with
water and drown sensors, if not properly
capped and sealed.
e. Geologic conditions
This method should not be used in areas
with high ground water because water
interferes with vapor detection (as explained
above).
3. Considerations
a. Manual monitoring systems require monthly
time investment to obtain samples and have
results analyzed.
The time required increases for each tank
included in system.
Large sites require considerable time each
month.
Samples are often sent offsite for analysis.
b. Owners and operators of existing USTs that
have not been upgraded should consider
using spill and overfill protection when using
vapor monitoring.
Slide 71: Discuss slide.
Slide 72: Discuss these and other consider-
ations that are appropriate for your area.
Hand out the vapor monitoring exercise from
Appendix II. Discuss as a group once students
have had the opportunity to work through the
problem.
Slide 73: (This slide has been removed.)
Chapter Four, Page 23
-------
Lecture Notes
Instructional Aids
F. Statistical Inventory Reconciliation (SIR)
The five monthly monitoring methods described so
far were all identified in the Federal regulations that
became effective in December 1988. The
regulations provided, however, that other release
detection methods could be approved in the future if
those methods could meet EPA's performance
standards for release detection. In June 1990, EPA
published a standard test procedure for an
additional release detection method that is known
as Statistical Inventory Reconciliation (SIR). SIR
methods must be evaluated using EPA's standard
test procedure or an equivalent procedure to prove
they can meet EPA's release detection performance
standards.
1. How SIR works
Statistical inventory reconciliation (SIR) analyzes
inventory, delivery, and dispensing data collected
over a period of time to determine whether or not a
tank system is leaking.
a. Each operating day the operator measures
the product level using a gauge stick or
other tank level gauge. A calibration chart
specific to the tank is used to convert
product level into product volume.
The operator also keeps complete records
of all withdrawals from the LIST and of
deliveries to the LIST.
After data have been collected for the
period of time required by the SIR vendor,
this information is provided to the SIR
vendor.
b. The SIR vendor uses sophisticated
statistical software to conduct a
computerized analysis of the data that can
identify if the LIST is leaking.
c. Every month, the SIR vendor reports the
results of the analysis to the operator, who
keeps monthly reports on file for at least 12
months.
Slide 73A: Discuss basic SIR operation.
Chapter Four, Page 23A
-------
Lecture Notes
Instructional Aids
d. The Federal requirements for monthly
release detection are-met-if the'SIR analysis*
is performed every month, is capable of
detecting release rates of at least 0.2 gallons
per hour (with a probability of detection of
0.95 and a probability of false alarm of 0.05),
and the monthly results are available at the
LIST facility. State and local requirements
can be more restrictive.
e. Also, SIR can qualify as a tank tightness test
if it meets the Federal requirements of
detecting release rates of at least 0.1 gallons
per hour with a probability of detection of
0.95 and a probability of false alarm of 0.05.
(Tank tightness testing is discussed in
section III.B below.) State and local
-*.*»:< smrequirementSiCan be-more restrictive.
2. When SIR is appropriate
a. UST system characteristics
SIR procedures apply to fueling sites where
the required measurements can be taken
every operating day. It is not appropriate for
unattended facilities, unless the required
data can be retrieved remotely.
SIR systems may be used on tanks up to the
capacity for which an individual SIR system
is evaluated. SIR systems are generally not
< certified for use on tanks larger than 18,000
gallons.
b. Product characteristics
SIR is generally not restricted by product
type.
c. Soil conditions
SIR is not affected by soil type.
d. Climatic factors
Changes in climate, especially temperature,
affect the data used in SIR, so SIR vendors
must take climatic factors into consideration
in their procedures.
Slide 73B: Discuss Federal requirements, noting
that tank tightness testing will be described in next
section.
Slide 73C: Discuss these characteristics.
Slide 73D: Note that SIR vendors must be able
to account for variables introduced by climatic
factors and geologic conditions.
Chapter Four, Page23B
-------
Lecture Notes
Instructional Aids
e. Geologic conditions
Ground water around a tank may hide a
hole or distort the data to be analyzed by
temporarily reducing or preventing the
product from leaving the tank. To detect a
leak in this situation, the UST operator must
check for water at least once a month.
3. Considerations
SIR can be used for tank and piping
systems.
SIR should not be confused with other
release detection methods that also rely on
periodic reconciliation of inventory,
^.withdrawal, or delivery data. Unlike manual
tank gauging and automatic tank gauging
systems (described earlier) or inventory
control (described in the following section),
SIR uses a sophisticated statistical analysis
of data to detect releases. This statistical
analysis can only be done by competent
vendors of SIR systems.
The procedures used by the SIR vendor
must be evaluated against EPA's standard
test procedures (or an equivalent protocol)
to confirm that the procedures are capable
of meeting the Federal regulatory
requirements regarding the detection of
minimum release rates and the probabilities
of detection and false alarm.
Tank level and meter readings should be
taken carefully at the same time each
operating day, at a time when no product is
being delivered or dispensed. SIR does not
require that the tank be out of service for
extended periods.
Data can be transmitted to the SIR vendor
on paper or by using computer modems or
diskettes.
SIR can identify problems other than
leaking systems, such as miscalibrated
meters, tilted tanks, and loss resulting from
theft.
Slide 73E: Emphasize that SIR should not be
confused with other inventory methods, because
SIR depends on extremely sophisticated statisti-
cal analysis that requires a competent SIR vendor
using software and computers effectively.
Slide 73F: Discuss these considerations.
Chapter Four, Page 23C
-------
Lecture Notes
Instructional Aids
SIR requires minimal investment of staff time
and equipment costs (usually involving a
gauge stick and pastes that help identify
product and water levels). The cost of
services provided by SIR vendors compares
favorably with the cost of other leak detection
methods.
State and local governments can place
restrictions on the use of SIR for compliance
purposes.
Chapter Four, Page23D
-------
Lecture Notes
Instructional Aids
LEAK DETECTION METHOD: INVENTORY
CONTROL & TANK TIGHTNESS TESTING
Inventory control must be combined with
tank tightness testing to meet the leak
detection requirements. This combined
method can be used only during the first
ten years following the installation of a new
UST or the upgrade of an existing UST.
Existing USTs without upgrade cannot use
this combined method after December 1998.
A. Inventory control
1. How inventory control works
Inventory control is a daily accounting
system in which records of input and
output of a product are compared to
the measured product volume in an
UST.
Inventory control is only
acceptable as a leak detec-
tion method when used with
periodic tank tightness
testing.
Volume of product in the
tank, deliveries, and sales
are recorded daily.
Each month the owner or
operator balances accounts
of deliveries and product
sold from the tank with daily
volume measurements.
This method must be able to
detect a monthly loss of 1.0
percent of flowthrough plus
130 gallons.
If overage or shortage
equals or exceeds 1.0 per-
cent of the tank's flow-
through volume plus 130
gallons of product, the UST
may be leaking.
Slide 74: Discuss slide.
Slide 74A (graphic photo): Inventory Control
with tank tightness testing.
Slide 75: Explain that inventory control is a
daily accounting system (vs. manual tank
gauging which is performed weekly).
Leak is indicated if there is an overage or short-
age in tank volumes. Shortages could be due to
leaks and release into the environment; over-
ages could be the result of a hole into which
water is seeping.
Chapter Four, Page 24
-------
Lecture Notes
Instructional Aids
a. Daily tank gauging and
reconciling
Each morning and evening
(or after each shift) product
level is measured with a
gauge stick marked to one-
eighth of an inch. This pro-
cedure should be conducted
at regular intervals.
A gauge stick is inserted
vertically through the fill pipe
until it touches the tank's
bottom.
Product-finding paste
can be used to high-
light the level on the
gauge stick.
A calibration chart specific
to the tank is used to con-
vert product level into pro-
duct volume. Similarly,
water at the bottom of the
tank is measured and ac-
counted for in the recon-
ciliation.
Every day, product volume,
withdrawals, and deliveries
are recorded.
b. Monthly reconciliation
At least monthly, daily data
on product volume, and the
amounts of product de-
livered to and withdrawn
from the UST are reconciled.
Daily overages and short-
ages that fluctuate randomly
around zero are common for
USTs without a leak.
Slide 76: Describe the method of record-
keeping.
Slide 76A (photo): Person using gauge to
measure tank volume.
Slide 77: Mention that it is essential that gaug-
ing be performed accurately.
Slide 78 (graphic): Part of a sample calibration
chart. Note that appropriate tank size column
must be used to convert measured depth in
inches into product volume in gallons.
Slide 79 (graphic): Shows part of a monthly
reconciliation form.
Chapter Four, Page 25
-------
Lecture Notes
Instructional Aids
2.
If monthly overage or short-
age is greater than or equal
to 1.0 percent of tank's flow-
through volume plus 130
gallons of product, the UST
may be leaking.
If this overage or short-
age occurs over two
consecutive months,
the owner or operator
must report results to
local implementing
agency as a possible
leak.
c. Tank stock control
Dispensing meters must be
correctly calibrated to local
weights and measure stan-
dards to ensure accuracy of
inventory control.
Product delivery volumes
must be verified.
Unaccounted for additions
and withdrawals (such as
spillage or thefts) must be
included in the recon-
ciliation.
When inventory control is
appropriate
a. UST system characteristics
Any size tank is appropriate
as long as inventory control
can meet the performance
standard of 1.0 percent of
flow-through plus 130
gallons.
If the tank is not level you
will need to create your own
tank chart by adding incre-
ments of product and
reading the corresponding
level.
Slide 80: Review monthly procedures.
Slide 81: It is very important to recognize and
account for inaccurate meters and dispensers in
the inventory.
Slide 82 (graphic): Shows a flow chart of the
inventory control procedure. Talk through this.
Slide 83: Explain this performance standard.
Slide 83A (photo):
if tank is level.
Instrument used to measure
Chapter Four, Page 26
-------
Lecture Notes
Instructional Aids
b. Product characteristics
This method is effective for
gasoline and diesel fuel and
products that have similar
viscosities and thermal
properties.
If other products are stored,
owner/operator should en-
sure that this method can be
used satisfactorily with those
substances.
c. Soil conditions
Use is not restricted by soil
type.
d. Climatic factors
The ambient temperature
should be noted when
taking gauge readings.
Inventory control is most
accurate when performed at
same time each day.
The temperature difference
between newly-delivered
product and product in tank
limits accuracy of inventory
control.
Temperature increase or
decrease causes expansion
or contraction of product,
and may mask or imitate a
leak.
e. Geologic conditions
High ground water may
interfere with measurement.
If water level fluctuates,
testing will be able to catch
leak only during low water
levels.
Inventory control may be
inappropriate for areas with
permanent high ground
water.
Slide 84: Discuss slide.
Slide 85: Discuss climate vulnerability as it ap-
plies to your State.
Slide 86: Ground water poses the problem of
masking a leak.
Chapter Four, Page 27
-------
Lecture Notes
Instructional Aids
If water level is high
enough to cover a hole
in the leaking tank, it
can counteract outward
pressure of stored
product and mask a
leak.
A monthly measurement
using a gauge covered with
water-finding paste must be
taken to identify any water at
bottom of tank.
If water level in the tank
is over one-half inch,
water must be
removed.
Water volume should
be accounted for in the
reconciliation.
3. Considerations
a. Inventory control must be
combined with periodic tank
tightness tests. This com-
bined method can be used
for only ten years following
installation of new USTs or
upgrade of existing USTs.
b. This method requires:
Daily product gauging;
Calibration of meters; and
Recording and monthly
calculation of overage or
shortage compared to total
flow-through.
c. Staff time is required every
day, but doesn't require
much time. Also, many
facilities already practice
inventory control.
d. Small leaks may go un-
detected for a long period.
Mention this monthly requirement to determine
water level in the tank.
Slide 87: Discuss these considerations for
inventory control.
Slide 88: (This slide has been removed.)
Chapter Four, Page 28
-------
Lecture Notes
Instructional Aids
e. This method is applicable
only to metered storage
tanks.
f. Deliveries must be made
through a drop tube that
extends to within one foot of
the tank's bottom.
g. Inventory control results can
be affected by variation in
temperature, theft, tank tilt,
and discrepancies in meter
calibration, the tank calibra-
tion chart used, and delivery
overages or shortages.
B. Tank tightness testing
Tank tightness testing identifies leaks
in closed tank systems and must be
performed annually in existing non-
upgraded tanks and every five years in
new or upgraded tanks. Tank tight-
ness testing must be performed along
with inventory control, but this com-
bined method can be used only during
the first ten years following installation
of a new UST or upgrade of an exist-
ing UST. Neither method alone is an
acceptable method of leak detection.
The two types of tank tightness testing
are volumetric and non-volumetric
testing.
1. How tank tightness testing works
a. Volumetric testing
Changes in product level or
volume in tank over several
hours are measured
precisely (in milliliters or
thousandths of an inch).
Changes in product temper-
ature must also be meas-
ured in some methods to
account for temperature-
induced changes in product
volume.
Slide 89: This slide discusses possible sources
of error in interpreting inventory control results.
Slide 90: (This slide has been removed.)
Slide 91: Tank tightness testing OTT) identifies
leaks in a closed system. There are both volu-
metric and non-volumetric tests.
Slide 92: Discuss volumetric testing.
Slide 93 (graphic): Discuss level and tempera-
ture gauges.
Product level is measured over a period of
several hours.
Slide 93A (graphic photo): Petrotite.
Slide 93B (photo): Test site overview (petrotite).
Slide 93C (photo): Standpipe (petrotite).
Slide 93D (photo): Petrotite van and stand
pipe.
Chapter Four, Page 29
-------
Lecture Notes
Instructional Aids
Tests are conducted either
on partially filled or overfilled
tanks.
In a partially filled tank,
test is conducted with
the product level below
the top of the tank.
Because product level
changes occur in a
large surface area,
small changes in
volume create very
small changes in pro-
duct level.
In an overfilled tank
test, the tank is filled
until the product level
reaches the fill tube or
a standpipe located
above grade. Because
product level changes
occur in a small sur-
face area, small chang-
es in volume cause
large changes in level.
A net decrease in product
volume during testing
indicates a leak.
b. Non-volumetric testing
- Instead of monitoring for
changes in product level or
volume, these methods look
for some other evidence of a
leaking tank.
Acoustic testing methods
use equipment that 'listens'
for the sound of air bubbling
through a hole or the sound
of turbulent product at a
hole. This method may not
work well where the water
table is high or where the
tank sits in mud.
Slide 93E (photo): Reading results.
Slide 93F (photo): Sample chart.
Slide 94 (graphic): (This slide has been
removed.)
Slide 95 (graphic): Partially filled and overfilled
tanks.
Slide 96: There are several methods of non-
volumetric testing. An 'acoustic' test detects
small bubbles that may indicate a leak.
Chapter Four, Page 30
-------
Lecture Notes
Instructional Aids
Tracer methods add an
easily detected liquid or
vapor to the tank. The
backfill surrounding the tank
is monitored to see if the
tracer escapes.
c. General details
The test equipment is tem-
porarily installed in the tank,
usually through the fill pipe.
The tank must be taken out
of service for duration of
test. Tests may last 6-12
hours.
Test must be able to detect
loss of 0.1 gallon per hour
from any portion of tank that
routinely contains product.
Some methods require that
product in the tank be at a
certain level before testing.
The owner or operator
may have to add pro-
duct from another tank
on-site or purchase
additional product.
If new product is added to
tank to prepare it for testing,
the test cannot be con-
ducted until the temperature
of the tank contents has
stabilized.
Tank deformation and tem-
perature in tank must be al-
lowed to stabilize.
If product is added during
the test to make fine
adjustments in tank volume,
tank contents must again be
allowed to stabilize before
the test can continue.
Slide 96A (photo): Tanks holding a tracer gas,
helium.
Slides 97 and 98 (graphics): These graphics of
tanks show how changes in product tempera-
ture, and structural deformation of the tank can
be mistaken for a leak. These graphics help to
explain why a wait period is suggested before
tests are conducted.
Chapter Four, Page 31
-------
Lecture Notes
Instructional Aids
d. Application of test
A testing company performs
tests.
- Some methods require
tester to make measure-
ments and calculations by
hand.
Some methods are highly
automated and have com-
puterized measurements
and analysis.
2. When tank tightness testing is
appropriate
a. UST system characteristics
Tightness tests can be used
for both tanks and piping.
Tightness testing is primarily
used for tanks smaller than
15,000 gallons.
If tank tightness testing is
used for larger tanks, the
owner/operator should make
sure that the manufacturer
or vendor has proof that it
will meet the performance
standard when used on
larger tanks.
With automated tank tight-
ness test methods, up to
four tanks may be tested at
one time.
b. Product characteristics
- To date this method has
been used primarily in tanks
containing gasoline, diesel,
and light heating oils.
If other products are stored,
the owner or operator
should ensure that this
method can be used satis-
factorily with those
substances.
Note that tests are conducted by private com-
panies, not the owner or operator. Testing is
conducted annually or every five years
depending on whether the tank is unimproved or
has been upgraded or is new. The tester
temporarily installs equipment into the tanks.
Slide 99: Discuss applicability.
Chapter Four, Page 32
-------
Lecture Notes
Instructional Aids
c. Soil conditions
In volumetric testing, if the
backfill allows the tank to
'bulge,' one may have to
wait longer for tank to
stabilize between filling the
tank and beginning the test.
d. Climatic factors
In volumetric testing, wait at
least six hours between
delivery and testing to
stabilize temperature differ-
ences between added prod-
uct and product already in
tank. The wait time may
vary due to climate.
Temperature differen-
ces could cause dif-
ferences in densities,
which would result in
different product
capacitances.
Very cold weather will
cool product in fill pipe.
This cooler product
drops into the tank,
cooling the product
below the fill pipe, and
creates erroneous
readings.
e. Geologic conditions
Ground-water level must be
determined before this
method is applied.
Presence of ground water
may mask an actual leak or
slow the rate at which
product is leaking.
If water table is higher than
location of hole in leaking
tank, ground water exerts
pressure on hole.
Slide 100: The wait time may have to be
lengthened if the backfill is such that it allows
the tank to bulge.
The presence of ground water is particularly
important with this method due to the infrequent
testing that takes place. If a leak is masked, it is
possible that it may not be detected for one or
five years when the next test is conducted.
Chapter Four, Page 33
-------
Lecture Notes
Instructional Aids
Water counteracts pressure
exerted on hole by fluid in
tank. This condition may
mask or slow a leak.
This is particularly important
with tank tightness testing
due to the length of time
between tests. A false read-
ing may not be caught until
the next test is performed.
The best methods can com-
pensate for high ground-
water levels if these levels
are known prior to tank
testing.
3. Considerations
a. Tightness tests must be
used with inventory control
method. This combined
method can only be used
for ten years following new
UST installation or upgrade
of existing USTs.
b. Tank must be taken out of
service during a test.
c. Access problems may make
it difficult to set up test
equipment. Tester should
be aware of layout of site
beforehand.
d. Permanent installation of
equipment is unnecessary.
e. Many different commercial
methods are available.
f. It is vital that tester follows
proper testing methods.
Slide 101:
limitations.
Discuss these considerations and
Slide 102: Review of Chapter Four. Answer
questions.
Chapter Four, Page 34
-------
CHAPTER FIVE
LEAK DETECTION METHODS FOR UST PIPING
How can you assist the owner or operator to meet the leak detection requirements for piping?
This chapter presents detailed information about the two types of UST piping systems, pressurized
and suction, and the requirements for piping monitoring and leak detection methods. This chapter
covers types of line devices, line testing methods, and monthly monitoring methods.
Lecture Notes
Instructional Aids
I. UST PIPING
The majority of UST leaks occur in the
piping system. Two varieties of piping sys-
tems for product delivery are pressurized
piping and suction piping.
A. Pressurized piping systems
1. A pump at the bottom of the tank
pushes product through the
delivery piping to the dispenser at
positive pressure, usually around
28 to 32 pounds per square inch
(psi).
2. Very large releases can occur
quickly because pumps continue
to operate when piping is broken
and force product through the
hole or break.
3. These systems are usually
chosen for high volume sites
because they deliver product
quickly.
B. Suction piping systems
1. A positive displacement pump, at
or near the point of end use,
reduces the pressure at the dis-
pensing unit, and atmospheric
pressure pushes the product
through delivery lines.
Slide 1: Chapter Five slides.
Slide 2: Introduce the chapter on leak detection
methods for piping.
Slide 2A (photo): Leaking pipe.
Slide 3: There are two varieties of piping. The
first is pressurized piping.
Explain that with pressurized piping releases can
occur very quickly, posing a threat to the
environment.
Slide 4: The second variety of piping is suction
piping.
Slide 4A (photo): Suction pump dispensers.
Slide 4B (photo): Suction pump dispensers.
Chapter Five, Page 1
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Lecture Notes
Instructional Aids
2. When the pump is shut off or a
leak in the lines occurs, suction is
interrupted, and product flows
back through the piping toward
the tank.
Some product remains con-
tained in the lines by one or
more check valves within the
pipe system.
At the point of a line failure,
some product can not drain
back into the tank and es-
capes into the environment.
3. Two general types of suction
systems exist:
In the 'European' system,
the location of the check
valve is immediately below
the pump. Also, the slope
of the piping will allow pro-
duct in the piping to drain
back into the tank when
suction is released.
In the 'American' system,
the check valve is located at
the top of the tank (angle
check) or at the bottom of
the suction line (foot valve).
Both systems are used in the
United States.
4. Suction piping systems deliver
product slowly, so they are only
used where speed of delivery is
not a factor. These systems also
require that the dispenser and
tank are near each other.
Explain that when the pump is shut off, the suc-
tion is interrupted. If there is a leak, the product
will flow back toward the tank. The volume of
the release is much less for suction piping than
for pressurized piping because no pressure
forces product from the lines.
Slide 4C (graphic photo): Suction piping.
Mention the 'European" and 'American" systems.
Slide 5 (graphic): This diagram shows the
differences between the "American" and
"European" systems. Both are used in the
United States.
Discuss when suction piping is used. Limitations
of this system are the slow delivery rate, and the
short distance allowed between the tank and the
dispenser.
Chapter Five, Page 2
-------
Lecture Notes
Instructional Aids
II. LEAK DETECTION FOR UST PIPING
Federal regulations require that all UST
piping systems that routinely contain pro-
duct be tested for leaks. This may or may
not include the vent lines, depending on the
State requirements. Depending on the test
method, piping may be tested separately or
in conjunction with the tank.
A. Deadlines
1. Pressurized piping
* - New piping must comply
with UST leak detection
requirements when
installed.
« - Existing piping must comply
with UST leak detection
requirements by December
1990.
2. Suction piping
Leak detection is not
required for either new or
existing piping of the
"European" type described
earlier.
Other "American" suction
piping types need to meet
the following deadlines.
New piping must
comply with UST leak
detection requirements
when Installed.
Existing piping must
comply with UST leak
detection requirements
according to the
following timetable:
Slide 6: Introduce this section on deadlines and
requirements for leak detection.
Note: Much of the information is the same for
tanks and piping. You may not wish to repeat
those parts of this section that are redundant
with earlier material.
Slide 7: Discuss regulations. You may want to
repeat that 'new piping" refers to piping installed
after December 1988.
Slide 8: Discuss suction piping deadlines,
emphasizing difference between "American" and
"European" style systems and their differing
compliance requirements.
Chapter Five, Page 3
-------
Lecture Notes
Instructional Aids
Installation Must Comply
Date By
Before 1965
1965-1969
1970-1974
1975-1979
19SO-1988
December 1989
December 1990
December 1992
December 1993
* Or If Installation date Is unknown.
B. Requirements
1. Pressurized piping (new and
existing)
Each pressurized piping run
must have an automatic line
teak detector 01D).
Pressurized piping must also
have one of the following:
Monthly ground-water
monitoring; or
Monthly vapor monitor-
ing; or
Monthly interstitial mon-
itoring; or monthly SIR;
Annual tightness test
2. Suction piping
No leak detection is required
if the suction piping is
designed with:
Enough slope so that
the product in the pipe
can drain back into the
tank when suction is
released; and
Only one check valve,
which is as close as
possible beneath the
pump in the dispensing
unit.
Slide 9: Review chart.
Slide 10 (graphic): Pressurized piping system.
Note piping extending to bottom of tank.
Slide 11: Requirements for pressurized piping.
Slide 12: Discuss the leak detection
requirements for suction piping. Note that the
requirements are for systems that do not meet
the design requirements for exemption from leak
detection.
Chapter Five, Page 4
-------
Lecture Notes
Instructional Aids
If a suction line does not meet all of these
design criteria, one of the following leak
detection methods must be used:
A line tightness test at least every three years;
or
Monthly vapor monitoring; or
Monthly SIR;
Monthly ground-water monitoring; or
Monthly interstitial monitoring.
C. Methods
1. Automatic line leak detectors
Two types are currently available:
- Automatic flow restrictor; and
- Automatic shutoff device.
2. Line tightness testing methods
Two general approaches are currently used:
- Direct volumetric testing; and
- Indirect tightness testing.
3. Monthly monitoring methods
Four types exist:
- Interstitial monitoring;
- Ground-water monitoring;
- SIR monitoring; and
- Vapor monitoring.
Slide 13: Introduce the acceptable methods
of leak detection or piping. Each method will
be discussed later in this chapter.
Sllde14: Leak detection methods.
Chapter Five, Page 5
-------
Lecture Notes
Instructional Aids
D. Requirements for PD/PFA
1. Line tightness testing and automatic line leak
detectors must be capable of detecting the
leak rate or quantity specified for that method
with a probability of detection (PD) of 0.95 and
a probability of false alarm (PFA) of 0.05.
There are two PD/PFA compliance deadlines:
By December 1990, tightness testing for
piping must meet PD/PFA requirements;
By September 1991, automatic line leak
detectors must meet PD/PFA requirements.
However, methods permanently installed
before the applicable compliance deadline are
not required to meet the PD/PFA
requirements.
E. Standard test procedures
As discussed earlier in Chapter Four, Section
I.D., EPA has developed standard test
procedures (also known as protocols) that
enable manufacturers of release detection
methods and third-party evaluators of those
methods to demonstrate that the methods can
meet the Federal release detection
requirements. EPA published standard test
procedures for evaluating pipeline leak
detection systems in September 1990.
Slide 15: Discuss PD/PFA "95 and 5"
requirements.
Chapter Five, Page 6
-------
Lecture Notes
Instructional Aids
III. AUTOMATIC LINE LEAK DETECTORS
A. Automatic flow restrictors
1. How automatic flow restrictors
work
Restrictors, located at the
pumps, monitor the line
pressure and restrict flow if
a possible leak is indicated.
When pressure in the pump
delivery system drops below
a preset threshold, common-
ly 1 to 2 psi, a test is auto-
matically performed.
During the test product flows
through line at 1.5 to 3
gal/h.
Line leak detectors must
detect 3 gal/h release at 10
psi pressure, within 1 hour.
Leaks greater than 3 gal/h
are indicated if more than 2
seconds are required to fully
pressurize the line.
If test does not indicate a
leak, normal flow is
resumed.
Restrictors do not shut the
system off entirely, but limit
product flow to 3 gal/h.
2. When automatic flow restrictors
are appropriate
This method is used only in
pressurized piping.
Most gas station USTs al-
ready have automatic flow
restrictors (Red Jackets).
Slide 16: Describe how automatic flow restric-
tors work and how they are set up. Discuss the
devices that are particularly common in your
State.
Slide 17: Continue the discussion of automatic
flow restrictors.
Slide 18: Discuss when automatic flow restric-
tors are appropriate.
Slide 18A (photo): Red Jacket.
Chapter Five, Page 7
-------
Lecture Notes
Instructional Aids
3. Considerations
This method causes a slight
lag in product delivery even
when there is no leak.
At high altitudes or high
temperatures, vapors are
more likely to form in piping.
This increases the amount
of time required for product
to reach operating pressure
and may falsely indicate a
leak.
If additional time is
spent pressurizing the
line, vapors will usually
be reabsorbed into the
liquid.
On-site staff may tamper
with system to avoid delays
in product delivery.
Requires little owner or
operator involvement.
Tests can not be run while
dispensers are in use.
About five minutes between
dispensings at the UST are
needed for accurate testing.
Typical time between dis-
pensings should be con-
sidered when selecting a
method of piping leak
detection.
B. Automatic flow shutoff devices
1. How automatic flow shutoff
devices work
There are two different types of
automatic flow shutoff devices:
one system monitors for an
increase in line pressure; the
other monitors for a decrease in
line pressure.
Slide 19: Discuss these and other factors that
may need to be considered before using
automatic flow restrictors.
Slide 20: There are two types of automatic flow
shutoff devices that will be discussed: pressure
increase monitors and pressure decrease
monitors.
Chapter Five, Page 8
-------
Lecture Notes
Instructional Aids
a. Pressure increase monitor
The normal rate of
pressurization in pipes is
calculated when the testing
system is set up.
When the pump is activated,
the rate of increase in line
pressure is measured.
It will take longer than usual
for the piping to become
fully pressurized if there is a
leak.
If pressure does not rise
quickly enough, the system
automatically shuts down.
The level of automation
varies from system to
system.
Automatic flow shutoff
systems are permanently
installed.
b. Pressure decrease monitor
System monitors line pres-
sure over several minutes
when dispenser is not in
use.
If constant pressure can not
be maintained or if pressure
decreases more quickly than
its normal rate, a leak is
indicated, and the pump is
shut down.
Generally, more than one
test which indicates a leak is
required before system
shuts down.
The level of automation
varies from system to
system.
Such systems are
permanently installed.
Slide 21: In this method the amount of time it
takes to fully pressurize a line is measured.
Automatic shutoff occurs when the length of time
for full pressurization is longer than usual,
indicating a possible leak.
Slide 22: This method measures decreasing
pressure in the lines over a period of time when
the lines are inactive. The inability to maintain
normal pressure may indicate a leak.
Chapter Five, Page 9
-------
Lecture Notes
Instructional Aids
2. When automatic flow shutoff
devices are appropriate
This method is used for
pressurized piping only.
Typical time between
dispensings should be con-
sidered when selecting a
method of piping leak
detection.
3. Considerations
Flow shutoff devices are
subject to tampering if they
are not locked or tamper-
proofed in some way.
As with flow restrictors, tests
cannot be run while
dispensers are in use. At a
minimum, about five minutes
between dispensing at the
UST are needed for
accurate testing.
A longer interval
between dispensings
(up to one hour) is
necessary to detect
small leaks.
Automatic flow shutoff
devices provide nearly con-
tinuous leak detection and
require little time from staff.
Slide 23: Discuss slide. Mention when the
devices are appropriate, and that they allow for
only minimum product loss.
Slide 24: Discuss these and other factors that
should be considered when using automatic flow
shutoff devices.
Chapter Five, Page 10
-------
Lecture Notes
Instructional Aids
IV. LINE TIGHTNESS TESTS
A. Direct volumetric line tightness test
1. How direct volumetric line
tightness tests work
The line is isolated from the
tank, and is tested for its
ability to maintain pressure.
A pressure loss
indicates a potential
leak.
The test must be able
to detect a leak of 0.1
gal/hat 1.5 times the
normal line operating
pressure.
A hand pump or a dispenser
and submerged pump is
used to pressurize the
piping leading back to the
tank.
The amount of volume lost is
determined in one of several
ways:
If pressure decreases
in the piping system,
product is added to
return pressure to
original test level. The
leak rate is estimated
by measuring the
amount of product
added.
The volume of product
lost over time is
observed in an above-
ground tube that is
connected to pressur-
ized piping.
Slide 25: There are two line tightness testing
methods - direct volume and an indirect line
tightness test. Each method will be discussed in
this chapter.
Slide 26: Describe how a volumetric line
tightness test is conducted. Describe the
methods that are common in your State.
The piping between the tank and dispenser is
pressurized. The ability to maintain pressure is
measured in several ways. If a predetermined
volume is lost, a leak in the piping is indicated.
Mention that few of these devices are currently
available.
Slide 26A (photo): Line tightness testing equip-
ment.
Slide 26B (photo): Line tightness testing equip-
ment.
Slide 26C (photo): Line tightness testing equip-
ment.
Chapter Five, Page 11
-------
Lecture Notes
Instructional Aids
A pressure gauge on
the hand pump, or
temporarily installed on
the dispenser, can be
used to indicate pres-
sure change, which is
converted to a leak
rate.
If a 0.1 gal/h per hour leak
rate is found, a leak is
indicated.
2. When the direct volumetric line
tightness test is appropriate
This method can be per-
formed alone or in con-
junction with other
monitoring methods.
With certain variations on
tests, line tightness testing
may be performed on both
pressurized and suction
systems.
3. Considerations
The line must be shut down
for several hours for the test.
This method requires no
permanent equipment and
can be performed along with
tank tightness testing.
Test needs to be performed
only once every three years
for suction piping. Line
tightness testing can be
used as the only method of
line leak detection for suc-
tion piping.
There are generally more
problems with line tightness
testing than with tank
tightness testing. These
problems are difficult to
resolve due to poor fittings
and gaskets, vapor pockets,
bad check valves, etc.
Slide 27: Can be used in conjunction with tank
tightness testing.
Slide 28: Discuss these and other consider-
ations as they apply to your State.
Chapter Five, Page 12
-------
Lecture Notes
Instructional Aids
B. Indirect line tightness test
1. How the indirect line tightness
test works
a. In an indirect line tightness
test, piping is tested as a
part of a full tank system
test. Fluid loss over time in
a closed tank and piping
system is examined to deter-
mine presence of a leak.
Procedures are the same as
for tank tightness test with
the following additions:
Overfill method must be
used, so that piping as well
as tank is full of product.
If test indicates a leak, tank
is tested alone.
If no leak is found in tank,
piping is assumed to be
leaking.
If tank is leaking, separate
test of piping must be
conducted.
2. When the indirect line tightness
test is appropriate
This method must be done
in conjunction with tank
testing; tanks and piping
might be on different test
schedules, making an
indirect test impractical.
With certain variations on
tests, line tightness testing
may be performed on both
pressurized and suction
systems.
If low pressure is put on
piping, it is necessary to
detect very small leaks to
pass the pressure piping 0.1
gal/h test requirement.
Slide 29: This method tests piping and the tank
as one system. If a leak is suspected, then a
systematic method of locating the leak is used,
testing each system part until the leak is
isolated.
Discuss this procedure.
Slide 30: This method must be done along with
tank testing, and can be used on both pressur-
ized and suction piping.
Chapter Five, Page 13
-------
Lecture Notes
Instructional Aids
3. Considerations
This method must be per-
formed as part of tank test;
therefore, UST system must
be shut down for at least
several hours.
Requires no permanent
equipment, and can con-
veniently be performed
along with tank tightness
testing.
Test must be performed only
once every three years for
suction piping. Line tight-
ness testing can be used as
the only method of line leak
detection for suction piping.
There are generally more
problems with line tightness
testing than with tank
tightness testing. These
problems are difficult to
resolve and are due to poor
finings and gaskets, vapor
pockets, bad check valves,
etc.
Indirect tests can only show
that the entire UST system is
leaking. Tanks and piping
will have to be tested
separately to identify the
source of the leak.
Slide 31: Discuss these considerations for in-
direct line tightness tests.
Chapter Five, Page 14
-------
Lecture Notes
Instructional Aids
V. MONTHLY MONITORING METHODS
A. Secondary containment with
Interstitial monitoring
Methods, applications, and con-
siderations of interstitial monitoring
with secondary containment for piping
systems are similar to those for tanks.
1. How interstitial monitoring works
a. Trench liners
Backfill and piping are
placed in a lined trench.
The trench should be sloped
away from the tank
excavation to differentiate
between tank leaks and
piping leaks.
An interstitial monitor is
placed between piping and
the trench liner.
b. Double-walled piping
Piping that carries the pro-
duct is contained within a
larger outer pipe.
The outer pipe usually
drains to a sump that can
be monitored for leaks.
Other methods use an
interstitial monitor placed
between inner and outer
piping.
2. When secondary containment
with interstitial monitoring is
appropriate
a. UST system characteristics
Can be used for both tanks
and piping.
Slide 32: Discuss the use of interstitial
monitoring with piping. It is very similar to that
used with tank systems; however, some differen-
ces will be discussed.
Slide 33: Discuss trench liners.
Note that the system can be arranged such that
leaks in piping and tanks can be differentiated.
Slide 34: Discuss double-walled piping.
The same applications of tank interstitial
monitoring apply to piping. There are few
restrictions.
Slide 35: Discuss when secondary containment
is appropriate.
Chapter Five, Page 15
-------
Lecture Notes
Instructional Aids
Secondary containment is
impractical for existing
piping, because it involves
either excavating all piping
runs and installing trench
liners, or replacing existing
piping with double-walled
piping.
i
»b. Product characteristics
This method can be used
for all types of fuels.
c. Soil conditions
Use is not restricted by soil
type.
d. Climatic factors
This method can be used in
all climatic conditions;
however, in areas with heavy
rainfall, a fully enclosed
containment system should
be used to prevent rain from
interfering with monitoring
system.
e. Geologic conditions
In areas with high ground
water, a fully-enclosed con-
tainment system should be
used to prevent ground
water from interfering with
the monitoring devices.
3. Considerations
Correct installation of trench
liners is essential because
piping trenches are narrow
and long. To cover these
areas requires piecing
together small pieces of
liner. Trained and
experienced professionals
can minimize the number of
seams in the liner and en-
sure correct installation.
Slide 36: This method can be used for all fuel
types.
Slide 37: Discuss climatic and geologic
considerations.
Slide 38: Discuss these considerations and any
others that apply to your State.
Installing liners in trenches can be very difficult
due to the number of seams required to line a
piping system.
Chapter Five, Page 16
-------
Lecture Notes
Instructional Aids
Proper installation of double-
walled piping is also very
important, and requires a
professional.
Piping monitoring can often
be integrated with the tank
monitoring system.
This is the only leak detec-
tion method that prevents
product from entering the
environment, thus reducing
potential for cleanup costs.
B. Ground-water monitoring
1. How ground-water monitoring
works
a. Use of this method for
piping is the same as its use
for tanks, with the following
exception:
Additional wells will be
needed to monitor the area
affected by piping.
2. When is ground-water monitoring
appropriate
a. LIST system characteristics
Can be used to detect leaks
from tanks and piping.
May be used on any size
piping run. For larger sys-
tems, more wells are added.
May be retrofitted. When
retrofitting, installer must be
cautious not to puncture
piping.
b. Product characteristics
Density must be lower than
that of water. (Product must
float on top of water.)
Slide 39: Discuss ground-water monitoring as it
applies to piping. Note that additional wells may
be added approximately every 10 to 20 feet of
piping run to monitor the piping system.
Slide 40: Mention ground-water monitoring as it
applies to piping. Ground-water monitoring's
applicability for piping is the same as it is for
tanks.
Chapter Five, Page 17
-------
Lecture Notes
Instructional Aids
Product should not mix
easily with water. (If it
mixes, no free product layer
will form.)
Most commonly used for
gasoline and diesel fuels.
(Alcohols and water-soluble
chemicals are not
appropriate.)
c. Soil conditions
If this method is used alone,
soil between well and piping
must be coarse and per-
meable (for example sand or
gravel).
d. Climatic factors
Very low temperatures may
interfere with some
monitoring devices. Ice can
freeze monitors and interfere
with product-soluble
devices.
e. Geologic conditions
Level of ground-water table
must not be more than 20
feet below the surface.
Ideally, the ground
water should be
between 2 and 10 feet
from the surface.
Fluctuations in water table
level
If water level falls below
bottom of, or rises
above the top of, the
well screen, this
method alone becomes
insufficient to detect
released product.
If there is a steep gradient of
ground-water flow, the
product may bypass the
monitoring wells.
Slide 41: Product must be a floater* vs. a
"sinker," and must not mix readily with water.
Most commonly used with gasoline and diesel
fuels.
Slide 42: Explain the terms "porosity1 and
hydraulic conductivity." (Review these terms
from Chapter Three.)
Soil analysis may have to be conducted.
Slide 43: Discuss climatic problems relating to
ground-water monitoring as they pertain to your
State (e.g., areas with high or low annual rainfall,
or extreme temperatures).
Slide 44: Discuss geologic considerations.
Mention that it is essential to know the water
table level and gradient in order to have an
effective ground-water monitoring program.
Chapter Five, Page 18
-------
Lecture Notes
Instructional Aids
Because free product tends
to flow through fractures and
cavities in the soil, wells that
do not intercept these frac-
tures and cavities will not
detect free product.
3. Considerations
Ground-water monitoring of
underground piping can
easily be integrated with a
tank ground-water
monitoring system.
C. Vapor monitoring
1. How vapor monitoring works
a. Use of this method for
piping is same as its use for
tanks, with the following
exceptions:
Monitoring wells do not
need to be as deep as
those used for tank
monitoring.
When used for interstitial
monitoring, horizontal slotted
tubes at or below piping
level may be used rather
than conventional vertical
wells.
2. When vapor monitoring is
appropriate
a. LIST system characteristics
This method can be used
for both tanks and piping.
This method can be installed
as part of new or existing
tanks and piping.
May be retrofitted. When
retrofitting, installer must be
cautious not to puncture
piping.
Slide 45 (graphic): This graphic shows how the
well can be installed in what seems to be a good
place, but will still not detect a release due to
the geology.
Slide 46: Discuss site assessments, detection
devices, and how to avoid damage to pipes
during installation.
Slide 47: Discuss vapor monitoring as it applies
to piping. Shallower wells than those used for
tanks may be used.
Applicability is the same for a tank system.
This method is easily integrated with an LIST
vapor monitoring system.
Slide 48: General applicability.
Chapter Five, Page 19
-------
Lecture Notes
Instructional Aids
b. Product characteristics
Vapor monitoring must be
used with products that
vaporize readily. For
example, gasoline, diesel
fuel, and aviation fuels are
appropriate, but residual oil
No. 6 (used oil) is not.
c. Soil conditions
The backfill around the
pipes must be porous
enough to allow the vapors
to reach the monitoring
wells.
Backfill and nearby soil must
be clean and should not
contain substances that will
produce vapors.
Previously con-
taminated soil may lead
to false readings,
indicating releases.
d. Climatic factors
Temperature affects the
volatility of released product.
Sensors may need to be
adjusted for extreme
temperatures.
e. Geologic conditions
This method cannot be
used in areas with
heavy annual rainfall,
extremely moist cli-
mates or high ground
water.
Slide 49: Give examples of fuels that are most
appropriate for vapor monitoring due to their
high volatility (e.g., alcohol, jet fuels).
Slide 50: Discuss how backfills can distort
results, such as previous soil contamination.
Soil type can affect how the vapor can travel.
Slide 51 (graphic): This graph demonstrates
the effects of soil conditions on vapor con-
centrations at a vapor monitoring well. The ver-
tical axis is gasoline in ppm, the horizontal axis
represents time in days. Note that the vapor
concentrations are much lower in wet sand or
clay vs. the dry backfill. These are all readings
taken from the same release, at the same dis-
tance from the source.
Slide 52: Discuss slide.
Slide 53: Moisture-related considerations.
Chapter Five, Page 20
-------
Lecture Notes
Instructional Aids
The water fills spaces between the soil
particles, preventing vapor from travelling
through the soil. Vapors may also dissolve
in the moisture before reaching the
monitors.
3. Considerations
Vapor monitoring for underground piping
can easily be integrated with a tank vapor
monitoring system.
D. Statistical Inventory Reconciliation (SIR)
The three monthly monitoring methods described so
far were all identified in the Federal regulations that
became effective in December 1988. The
regulations provided, however, that other release
detection methods could be approved in the future if
those methods could meet EPA's performance
standards for release detection. In June 1990, EPA
published a standard test procedure for an
additional release detection method that is known
as Statistical Inventory Reconciliation (SIR). SIR
methods must be evaluated using EPA's standard
test procedure or an equivalent procedure to prove
they can meet EPA's release detection performance
standards.
Chapter Four described the applicability of SIR to
leak detection for tanks. Methods, applications, and
considerations of SIR for piping systems are similar
to those for tanks.
1. How SIR works
Statistical inventory reconciliation (SIR) analyzes
inventory, delivery, and dispensing data collected
over a period of time to determine whether or not a
tank system is leaking.
a. Each operating day the operator measures
the product level using a gauge stick or
other tank level gauge. A calibration chart
specific to the tank is used to convert
product level into product volume.
The operator also keeps complete records
of all withdrawals from the LIST and of
deliveries to the LIST.
Slide 54: Can easily be integrated with tank vapor
monitoring system. Discuss any other considera-
tions relevant to your State.
Slide 55: Discuss basic SIR operation.
Chapter Five, Page 21
-------
Lecture Notes
Instructional Aids
After data have been collected for the period
of time required by the SIR vendor, this
information is provided to the SIR vendor.
b. The SIR vendor uses sophisticated
statistical software to conduct an analysis of
the data that can identify if the UST is
leaking.
c. Every month, the SIR vendor reports the
results of the analysis to the operator, who
keeps monthly reports on file for at least 12
months.
d. The Federal requirements for monthly
release detection are met if the SIR analysis
is performed every month, is capable of
detecting release rates of at least 0.2 gallons
per hour (with a probability of detection of
0.95 and a probability of false alarm of 0.05),
and the results are available at the UST
facility on a monthly basis. State and local
requirements can be more
restrictive.
2. When SIR is appropriate
a. UST system characteristics
SIR procedures apply to fueling sites where
the required measurements can be taken
every operating day. It is not appropriate for
unattended facilities, unless the required
data can be retrieved remotely.
b. Product characteristics
SIR is generally not restricted by product
type.
c. Soil conditions
SIR is not affected by soil type.
Climatic factors
Changes in climate, especially temperature,
affect the data used in SIR, so SIR providers
must take climatic factors into consideration
in their procedures.
Slide 56: Discuss these characteristics.
Chapter Five, Page 22
-------
Lecture Notes
Instructional Aids
Geologic conditions
SIR for piping is not affected by geologic
conditions.
Considerations
SIR can be used for tank and piping
systems.
SIR should not be confused with other
release detection methods that also rely on
periodic reconciliation of inventory,
withdrawal, or delivery data. Unlike manual
tank gauging, automatic tank gauging
systems, and inventory control (described
earlier in Chapter Four), SIR uses a
sophisticated statistical analysis of data to
detect releases. This statistical analysis
can only be done by competent vendors of
SIR systems.
The procedures used by the SIR vendor
must be evaluated against EPA's standard
test procedures (or an equivalent protocol)
to confirm that the procedures are capable
of meeting the Federal regulatory
requirements regarding the detection of
minimum release rates and the probabilities
of detection and false alarm.
Tank level and meter readings should be
taken carefully at the same time each
operating day, at a time when no product is
being delivered or dispensed. SIR does not
require that the tank be out of service for
extended periods.
Data can be transmitted to the SIR vendor
on paper or by using computer modems or
diskettes.
SIR can identify problems other than
leaking systems, such as miscalibrated
meters, tilted tanks, and loss resulting from
theft.
Slide 57: Discuss these considerations.
Slide 58: Discuss these considerations.
Chapter Five, Page 23
-------
Lecture Notes
Instructional Aids
SIR requires minimal investment of staff time
and equipment costs (usually involving gauge
stick and pastes that help identify product and
water levels). The cost of services provided
by SIR vendors compares favorably with the
cost of other leak detection methods.
State and local governments can place
restrictions on the use of SIR for compliance
purposes.
Slide 59: Review LIST piping. Answer questions.
Chapter Five, Page 24
-------
GLOSSARY OF LEAK DETECTION TERMS
Ambient temperature - Temperature of areas surrounding the tank site.
Atmospheric pressure - The weight of overlying air at any given location.
Backfill - The material used to fill in the excavation zone after the tank is in place. The best
installation practice is to use sand or gravel as specified.
Check valve - The valve found in suction piping systems that closes when product begins to flow
backwards through the pipe.
Compatibility - The ability of a tank and piping to be unaffected by stored product.
Contamination -- The remains, liquid or vapor, in soil or backfill of releases at a site.
Density - The mass of a given substance per unit volume.
DNAPLs - Dense non-aqueous phase liquids.
Excavation liners - Flexible sheets of relatively impermeable substances (possibly made of various
synthetic materials, such as high-density polyethylene, polyester elastomers, epichlorohydrin, and
polyurethane) that separate the UST system and backfill from the native soil of the site.
Excavation zone ~ The entire area that must be dug up in order to install an UST.
Fill pipes -- The pipes connecting the underground tank to an aboveground fitting where a tank truck
connects its transfer hose.
Free product ~ The leaked product floating on the water table surface.
Grab samplers -- The bucket or bailer used to obtain ground-water samples, from monitoring wells.
Hydraulic conductivity - The measurement of the rate at which a liquid can flow through a particular
material, such as soil.
Interstitial space - The space between the wall of the tank or pipe and the secondary container or
lining.
Inventory control ~ A comparison of what is actually in the tank, based on measurement, to what
should be in the tank, based on records.
Overages - The amount by which volume measurement exceeds what is expected.
Overfill method - A method used on tank tightness testing during which the tank is filled until the
level of the product reaches the fill tube or a standpipe located above grade.
Performance standard - The minimum sensitivity of a method as specified in the regulation.
Permeability - A measurement of the ability of backfill or soil to permit liquids or gases to pass
through.
Appendix I, Page 1
-------
Porosity - The measurement of the extent to which a material contains small spaces through which
vapors or.liquid can pass.
Positive displacement pump - The pump placed at or near the point of end use on suction piping
systems; this pump creates a vacuum which draws product from the tank to the pump.
Pressurized piping systems -- These systems use a pump at the bottom of the tank to push the
product to the dispenser.
Product delivery lines - The piping that connects tanks and product dispensers (pumps).
Product-finding paste - Paste applied over a gauge stick to improve adherency of the product to the
stick and prevent creepage. The pastes change color in the presence of product, and are applied in
the area where one expects to see the product line, not on the entire stick.
Remote fill - Piping runs leading to a storage area for wastes, such as used oil, that are generally
installed as an afterthought, which therefore, are prone to leaks.
Restrictors -- Devices that keep the flow of product from the pump to the point of use below a certain
gal/h rate.
Retrofit - The process of upgrading an UST system with new technologies and/or products.
Shortage -- The amount that the volume measurement is below what is expected.
Solubility - The ability of a substance to dissolve in or mix with another substance.
Static tank system - A tank that is not in use; no product is added or removed.
Suction piping - The system uses a vacuum to draw the product from the tank to the pump.
Tank deformation -- Expansions and contractions of the tank resulting from fluctuating temperatures
of product within the tank and from the addition of product to the tank.
Thermal properties - Changes in product characteristics that occur in response to an increase or
decrease in temperature.
Underground storage tank (UST) - A system used to store and dispense petroleum products. An
UST system includes the tank(s), piping, and product dispensers. At least 10 percent of the
combined volume of the tank(s) and associated piping must be underground for the system to be
considered an UST system.
Vapor pockets - Vapor that becomes trapped in the manways, deadend piping, etc., after a tank has
been filled to or above the top of the tank.
Vapor recovery lines - Pipes that carry vapors back to the tank truck during off-loading, or back to
the UST during product dispensing.
Vent pipes - Pipes routed to the surface as aboveground vents.
Viscosity - The measurement of the ease with which a liquid flows.
Appendix I, Page 2
-------
Volatility -- The measurement indicating how readily a substance will vaporize.
Water table -- The level where ground water will rest in porous soil conditions under normal
atmospheric pressure.
Well screen - The perforated or slotted area of a well that allows product to enter the well.
Appendix I, Page 3
-------
CASE STUDY GUIDELINE
I. INTRODUCTION
The following guideline has been provided to help you develop a case study tailored to the
specific needs of each training session that can be used by participants to increase their
understanding of the leak detection requirements. This course is designed to be flexible, allowing you
to include your own 'designer* case study exercise in place of or in addition to the other exercises
provided in Appendix II. The goal of the case study is to apply the UST system characteristics and
regulatory information presented throughout the course to an actual or fictitious UST facility.
II. GUIDELINE FOR DEVELOPING A CASE STUDY
A. Identify the purpose of the case study.
1. What specific topics do you want to cover?
2. How much time are you allowing for the case study?
3. Have you considered your audience carefully (for example, their level of prior
knowledge in their field or their expectations for the training)?
B. Select an UST site.
1. Do you want an actual site or a fictitious site?
2. What characteristics are important about the site: UST system characteristics,
product characteristics, soil conditions, climatic factors, and geologic conditions?
3. Locate or create slides and maps of the site.
C. Develop a list of pertinent information that participants will need in order to make decisions
about the leak detection method at the site.
1. Have list ready prior to presentation of case study, or
2. Incorporate this task into the presentation of the case study as a group discussion.
You may want to use the "UST Site Characteristics' exercise found on pages 3 and 4
of this Appendix,
D. Break students into small groups. Provide a list of questions or issues to be addressed based
on the topics that you have chosen for the case study. Discussion topics may include:
Determining the important site characteristics at the case study's site.
Comparing UST leak detection methods in terms of suitability to the site, cost, ease of
use, and amount of time required for operation or maintenance.
Determining the appropriate leak detection method for the site.
Appendix II, Page 1
-------
Each group can discuss all questions, or each group can be assigned a specific
question/issue. Groups can prepare to present and justify their decisions to the whole class
based on regulations and materials presented in the course. Remind students that the
student manual should be used to check for the regulatory requirements.
E. Evaluate group decisions, making sure that all regulations and measures have been
addressed for the UST site being considered. This would be an appropriate time for open
group discussion and other suggestions.
Appendix II, Page 2
-------
EXERCISE - UST SITE CHARACTERISTICS
You are the UST "hotline" person for your State. UST owners and operators call you for
information on leak detection methods. The UST systems range from a single tank and large service
station systems to military installations. In order to make decisions and answer questions correctly,
you will need to know some information about the UST in question.
Develop a list of questions that you will use to obtain necessary information about the UST.
Consider the site characteristics discussed in the training manual, as well as logistical information that
you may want for your records.
Appendix II, Page 3
-------
SAMPLE LIST OF 'UST SITE CHARACTERISTICS" QUESTIONS
1. Name of owner/operator. Are you the owner or operator?
2. What is the purpose of the UST? (Service station, city installment.) Site location? (State,
county, city; for specific local regulations).
3. How many tanks are in question?
4. What is the date of tank installation? (May have to be approximate.)
5. Types of tanks. (May be more than one type.)
6. Size of tanks. (May be more than one size; therefore, different regulations may apply.)
7. Types of piping system in the UST. (Where is the pump located?)
8. What types of product are handled?
9. What is the backfill around the tanks? (Describe. Was it local fill or specifically delivered for
the UST?)
10. What is the soil type and ground-water level (if known)?
11. Is there any leak detection system used now? Describe.
12. If a leak is suspected, what indications do you have?
Appendix II, Page 4
-------
EXERCISE - ATGS
Review the scenario described in the following situation. You should decide individually, and then as
a group, what could be causing the described problem.
Scenario
Sal Robinson owns a small tank facility in
southern Louisiana. The tanks range from
7,000 to 15,000 gallons in size, and contain
heating oil and diesel fuel. Sal purchased the
facility in 1988. At that time, manual inventory
control was the leak detection method used.
No leaks had been detected using this
method. Two months ago Sal installed an
ATGS into the tank system. His records now
indicate substantial leaks in the UST system.
In your discussion you have found out that his
area is suffering a severe drought, a real shock
for an area with such a high annual rainfall.
Sal is concerned and confused about the new
leak detection method and the results that are
being obtained.
What suggestions do you have that may
explain the results? (Consider that the results
may be either true or false.)
Appendix II, Page 5
-------
EXERCISE - ATGS
(Instructor's Copy)
Review the scenario described in the following situation. Students should decide individually, and
then as a group, what could be causing the described problem. Lead a group discussion, making
sure that all relevant points are considered, and that the students fully understand the reasoning upon
which decisions were made.
Scenario
Sal Robinson owns a small tank facility in
southern Louisiana. The tanks range from
7,000 to 15,000 gallons in size, and contain
heating oil and diesel fuel. Sal purchased the
facility in 1988. At that time manual inventory
control was the leak detection method used.
No leaks had been detected using this
method. Two months ago Sal installed an
ATGS into the tank system. His records now
indicate substantial leaks in the UST system.
In your discussion you have found out that his
area is suffering a severe drought, a real shock
for an area with such a high annual rainfall.
Sal is concerned and confused about the new
leak detection method and the results that are
being obtained.
What suggestions do you have that may
explain the results? (Consider that the results
may be either true or false.)
Points to emphasize
The tanks may have been leaking for
some time, but they were not being
properly tested previously.
The tanks were leaking all along.
However, due to the usually high
amount of rainfall, the ground-water
levels were high enough to mask the
leaks. The area is now suffering from
a drought, which may affect the level of
ground water.
Staff may be making errors with the
use of the new system.
Wiring of the ATGS may be improperly
installed.
The temperature and volume
calibrations may not be correct in the
ATGS, giving false data.
Appendix II, Page 6
-------
EXERCISE - GROUND-WATER MONITORING
Review the scenario described in the following situation. You should decide individually, and then as
a group, whether ground-water monitoring is appropriate. Review the site characteristics mentioned in
Chapters Two and Three.
Scenario
Frank Lee has owned a small service station
near Lathrop Wells, Nevada, since 1958. All
four of the station's underground storage tanks
were installed at the time he bought the site.
The only products Frank stores in the tanks
are gasoline (both leaded and unleaded) and
diesel fuel. The tanks are located in soil that
consists of welded volcanic ash (or tuff) that
extends for several hundred feet below the
surface. The climate at the site (not far from
Death Valley) is generally arid, and
temperatures can exceed 110 degrees
fahrenheit during summer days. On the other
hand, sub-freezing temperatures at night are
not uncommon during winter months.
Is ground-water monitoring an appropriate leak
detection method in Frank's case? Why or
why not?
What further information, if any, do you need
from Frank, to determine this?
Appendix II, Page 7
-------
EXERCISE -- GROUND-WATER MONITORING
(Instructor's Copy)
Review the scenario described in the following situation. Students should decide individually, and
then as a group, whether ground-water monitoring is appropriate. Review the site characteristics
mentioned in Chapters Two and Three.
Scenario
Frank Lee has owned a small service station
near Lathrop Wells, Nevada, since 1958. All
four of the station's underground storage tanks
were installed at the time he bought the site.
The only products Frank stores in the tanks
are gasoline (both leaded and unleaded) and
diesel fuel. The tanks are located in soil that
consists of welded volcanic ash (or tuff) that
extends for several hundred feet below the
surface. The climate at the site (not far from
Death Valley) is generally arid, and
temperatures can exceed 110 degrees
fahrenheit during summer days. On the other
hand, sub-freezing temperatures at night are
not uncommon during winter months.
Is ground-water monitoring an appropriate leak
detection method in Frank's case? Why or
why not?
What further information, if any, do you need
from Frank, to determine this?
Points to emphasize
Is Frank required to have leak
detection for his tanks now?
[Yes, the tanks are 30 years old.]
Are the types of products Frank stores
appropriate for a ground-water
monitoring system?
[Yes, both gasoline and diesel fuel
have lower density than water, and do
not mix easily with water.]
Is the geology at Frank's site
appropriate for ground-water
monitoring?
[No, the water table is several hundred
feet below the surface.]
Is the soil appropriate?
[Unknown. Need to inquire about
conductivity of tuff.]
Is the climate appropriate?
[Yes. Short-term temperature changes
are not a problem.]
Is ground-water monitoring appropriate
for Frank?
[No. The water table is too low to
allow floating free product to be
detected.]
Is more information needed?
[No. Low water table rules out ground-
water monitoring.]
Appendix II, Page 8
-------
EXERCISE - VAPOR MONITORING
Review the scenario described in the following situation. You should decide individually, and then as
a group, whether vapor monitoring is appropriate for this situation. Review the site characteristics
mentioned in Chapters Two and Three, along with the considerations for vapor monitoring.
Scenario
Joe Carlisle has owned a small airfield in
Green Lake, Wisconsin for 20 years. He has
four USTs for various types of airplane fuels
that are all near the airfield. Near the hangers
are diesel, unleaded and leaded gasoline
tanks, and near the maintenance shop is one
750-gallon storage tank for used oil. The tanks
are installed in a glacial outwash area, which
consists of unsorted sands and gravels. The
depth of the water table averages 15 feet, and
remains fairly constant. An airplane owner has
suggested that instead of the time consuming
method of manual tank gauging, that Joe
consider vapor monitoring for the entire area.
Is vapor monitoring appropriate for this case?
Is there any other information that you might
need to make your decision?
Appendix II, Page 9
-------
EXERCISE VAPOR MONITORING
(Instructor's Copy)
Review the scenario described in the following situation. Students should decide individually, and
then as a group, whether vapor monitoring is appropriate for this situation. Review the site
characteristics mentioned in Chapters Two and Three, along with the considerations for vapor
monitoring. Lead the group discussion, making sure that all of the relevant points are considered.
Scenario
Joe Carlisle has owned a small airfield in
Green Lake, Wisconsin for 20 years. He has
four USTs for various types of airplane fuels
that are all near the airfield. Near the hangers
are diesel, unleaded and leaded gasoline
tanks, and near the maintenance shop is one
750-gallon storage tank for used oil. The tanks
are installed in a glacial outwash area, which
consists of unsorted sands and gravels. The
depth of the water table averages 15 feet, and
remains fairly constant. An airplane owner has
suggested that instead of the time consuming
method of manual tank gauging, that Joe
consider vapor monitoring for the entire area.
Points to emphasize
The stored product: While the airplane
fuel, gasoline, and diesel fuels are
appropriate for vapor monitoring, the
used oil is not, due to its low volatility.
Soil conditions: The glacial outwash
provides adequate porosity for vapor
travel, and is therefore appropriate for
vapor monitoring.
Ground water: The level of ground
water is appropriate, and does not
fluctuate greatly, and is therefore
appropriate for vapor monitoring.
Is vapor monitoring appropriate for this case?
Is there any other information that you might
need to make your decision?
Appendix II, Page 10
-------
Appendix II, Page 11
-------
Slide Section
Appendix III, Page 1
-------
CHAPTER 1-1
BASIC LEAK DETECTION
-------
SLIDE 1-2
BASIC LEAK DETECTION
Overview of leaking USTs
The need for leak detection
Leak detection methods
-------
SLIDE 1-3
DISTRIBUTION OF TANK TYPES AT
GASOLINE SERVICE STATIONS
Bare Steel
(84%)
NOT
PROTECTED
AGAINST
LEAKS
Cathodically Protected
(5%)
PROTECTED
AGAINST
LEAKS
Fiberglass-Reinforced
Plastic (11%)
Source: Regulatory Impact Analysis. August 24,1988.
-------
SLIDE 1-4
OVERVIEW OF LEAKING USTs
The Problem
15-20 percent of petroleum tanks may be leaking
Leaking tanks pose a threat to ground water and
surface water
-------
SLIDE 1-5
THE PROBLEM OF LEAKING USTs
The threat of leaking tanks also applies to
Contamination of surface waters
Fires and explosions
Toxic fumes
Cancer causing agents
-------
SLIDE 1-6
CAUSES OF RELEASES
Releases result from
Piping failures
Spills and overfills
Tank corrosion
-------
SLIDE 1-7
WHERE RELEASED PRODUCT TRAVELS
Water Supply
Well
Groundwater Flow
Dissolved
Gasoline
Components
Bedrock
-------
SLIDE 1-8
USES OF REGULATED USTs
Used Oil
(20%)
Chemical Storage
(3%)
Retail Motor Fuels
(39%)
Non-Retail
Motor Fuels (38%)
-------
SLIDE 1-9
OWNERSHIP OF USTs USED
TO STORE PETROLEUM
Government
(11%)
Farmers
(11%)
Industry
(39%)
Gas Stations
(39%)
-------
SLIDE MO
WHAT CAN LEAK DETECTION ACCOMPLISH?
Leak detection
Warns owner or operator of leaks
Prevents contamination of the environment and
risks to human health
-------
SLIDE 1-11
WHY IS LEAK DETECTION NECESSARY?
Leak detection can help save money in the long run
The average cleanup now costs $150,000
-------
SLIDE 1-12
WHY IS LEAK DETECTION NECESSARY?
Leak detection
Is a good business practice
Protects human health and the environment
Protects against liability suits
Is required by Federal, State, and local laws
-------
SLIDE 1-13
LEAK DETECTION METHODS
Three main types of leak detection
Internal Monitoring
Interstitial Monitoring
External Monitoring
-------
SLIDE 1-14
INTERNAL MONITORING
Internal monitoring methods
Inventory control combined with tightness testing
Manual tank gauging
Automatic tank gauging
Statistical inventory reconciliation
-------
SLIDE 1-15
INTERSTITIAL MONITORING
Interstitial monitoring method
Secondary containment with interstitial monitoring
-------
SLIDE 1-16
EXTERNAL MONITORING
External monitoring methods
Vapor monitoring
Ground-water monitoring
-------
SLIDE 1-17
PIPING MONITORING
Pressurized and suction piping have different
compliance time tables and testing requirements
Pressurized piping must have automatic line leak
detectors
-------
SLIDE 1-18
LEAK DETECTION METHODS FOR PIPING
Leak detection methods for piping operate on the same
principles as those for tanks
Tightness testing
interstitial monitoring
External monitoring
-------
SLIDE 1-19
BASIC LEAK DETECTION
Overview of leaking USTs
The need for leak detection
Leak detection methods
-------
CHAPTER 11-1
UST WALK-THROUGH
-------
SLIDE 11-2
WHAT IS AN UNDERGROUND STORAGE TANK (UST)?
i A system used to store petroleum products
i Includes the tank, piping, and product dispensers
-------
SLIDE 11-3
TYPICAL RETAIL GASOLINE STATION
Vent Pipes
Tank Truck
Delivery Hose
Submerged Pump
Assembly
Line Leak
Detector
Submerged Pump
Assembly
Product Dispensers
Product Delivery Line
-------
SLIDE 11-4
USE EXCEPTIONS
Certain USTs are not required to comply with Federal UST
regulations.
Farm or residential tanks 1,100 gallons or less
storing motor fuel for noncommercial purposes
Tanks storing heating oil for consumptive use on
the premises where stored
Tanks holding 110 gallons or less
Tanks on or above the floor of underground areas
Septic tanks and systems for collecting storm
water and waste water
-------
SLIDE 11-5
UST EXCEPTIONS
Flow-through process tanks
Emergency spill and overfill tanks
Surface impoundments, ponds, pits, or lagoons
-------
SLIDE 11-6
UST SYSTEM PARTS
TANKS
Typical tanks hold between 2,000 and 12,000 gallons
New tanks are generally constructed of:
-- Cathodically protected coated steel
- Fiberglass-reinforced plastic (FRP)
- Steel/fiberglass composite
-------
SLIDE 11-7
VAPOR RECOVERY LINES
Pipes that convey petroleum vapors back to the tank
trucks during off-loading or back to the LIST during
dispensing of product
-------
SLIDE 11-8
SITE TERMINOLOGY
Excavation zone
-- Area that must be dug up to install an UST
Backfill
-- Substance (usually clean sand, crushed rock, or
pea gravel) used to fill in excavation zone after
tank is installed
Water Table
-- Level where ground water will rest in porous soil
conditions under normal atmospheric pressure
-------
SLIDE 11-9
SCHEMATIC OF A SUBSURFACE
ENVIRONMENT
( TANK )
Excavation
Zone
Dry
Soil
Released
Product
t
Water Table
Aquifer
sZfxZfy&fy&fSfxS&fS^
Impermeable Boundary
-------
SLIDE 11-10
WHAT IS AN UST?
A system used to store and dispense petroleum
products
Includes the tank, piping, and product dispensers
-------
CHAPTER 111-1
SITE CHARACTERISTICS
-------
SLIDE 111-2
Important site characteristics that should be considered
when selecting the proper leak detection method
UST system characteristics
Product characteristics
Soil conditions
Climatic factors
Geologic conditions
-------
SLIDE 111-3
UST SYSTEM CHARACTERISTICS
Tank age (new vs. existing)
Tank size
Piping system
UST system size
-------
SLIDE 111-4
TANK AGE
New tanks and piping are those installed after
December 23, 1988
Existing tanks and piping are those installed before
December 23, 1988
-------
SLIDE IM-5
AGE OF TANK
Existing Tanks
Installed:
Before 1965 or
unknown
1965-1969
1970-1974
1975-1979
1980-1988
LEAK DETECTION
Must have leak detection
by:
December 1989
December 1990
December 1991
December 1992
December 1993
-------
SLIDE 111-6
TANK SIZE
Check tank size - some tanks may be too large to
use certain detection methods
-------
SLIDE 111-7
PIPING SYSTEM
Suction systems use a vacuum to draw the product
to the dispenser
Pressurized systems use a pump to push the product
to the dispenser
-------
SLIDE 111-8
UST SYSTEM SIZE
Number of tanks
Extent of site area
-------
SLIDE 111-10
TYPES OF STORED PRODUCTS
Petroleum
Hazardous substances
-- Include CERCLA hazardous substances
-- Do not include hazardous wastes regulated under
40 CFR Parts 260-270
-- Use secondary containment for hazardous
substances
-------
SLIDE 111-11
PRODUCT CHARACTERISTICS
IMPORTANT IN LEAK DETECTION
Solubility
Density
Viscosity
Volatility
Thermal effects
Compatibility with tank and piping materials
-------
SLIDE 111-12
CHARACTERISTICS OF STORED PRODUCTS
Solubility
The ability of a substance to dissolve in or mix with
another substance
-------
SLIDE 111-13
CHARACTERISTICS OF STORED PRODUCTS
Density
Refers to the mass of a given substance per unit of
volume
-------
SLIDE 111-14
*
CHARACTERISTICS OF STORED PRODUCTS
Gasoline floats on water; DNAPLs do not float
-------
SLIDE 111-15
CHARACTERISTICS OF STORED PRODUCTS
Viscosity
A measurement of the ease with which a liquid flows
-------
SLIDE 111-16
CHARACTERISTICS OF STORED PRODUCTS
Volatility
A measurement indicating how readily a substance
will vaporize
-------
SLIDE MM 7
CHARACTERISTICS OF STORED PRODUCTS
Thermal effects
Refers to changes in product characteristics that
occur in response to an increase or decrease in
temperature
Compatibility
The ability of a tank and piping to be unaffected by a
stored product
-------
SLIDE 111-18
SOIL CONDITIONS
Relative porosity
Hydraulic conductivity
Contamination
-------
SLIDE 111-19
RELATIVE POROSITY
A measurement of the extent to which a material
(e.g., soil or backfill) contains small spaces through
which vapors or liquids can pass
-------
SLIDE 111-20
THE EFFECT OF SOIL CONDITIONS ON
VAPOR CONCENTRATIONS AT A WELL
8000
Dry gravel backfill
Dry sitty sand
Moist sand backfill
Wet sand or clay
10 20
Number of Days
30
-------
SLIDE 111-21
HYDRAULIC CONDUCTIVITY
A measurement of the rate at which a liquid
(e.g., water) can flow through a particular material
such as soil
-------
SLIDE 111-22
CONTAMINATION
Soil or backfill may be contaminated by past releases
-------
SLIDE 111-23
CLIMATIC FACTORS
Temperature
Rainfall
-------
SLIDE 111-24
GEOLOGIC CONDITIONS
Effects of ground water
Important ground-water variables
-------
SLIDE 111-25
PRESENCE OF GROUND WATER
Presence of ground water may mask an actual leak or
slow the rate of the leak
-------
SLIDE 111-26
THE EFFECT OF GROUND WATER ON THE
RATE AND FLOW THROUGH A HOLE
IN AN UST
Water table above level of
leak. Ground water enters
tank through hole.
Water
Table
Water table below level of tank,
Product escapes from hole.
Water Tab*
-------
SLIDE 111-27
GROUND-WATER TABLE
Depth of water table
Large fluctuations in water table levels
Gradient of ground-water flow
-------
SLIDE 111-28
SITE CHARACTERISTICS TO CONSIDER WHEN SELECTING
A LEAK DETECTION METHOD
UST system characteristics
Product characteristics
Soil conditions
Climatic factors
Geologic conditions
-------
CHAPTER IV-1
LEAK DETECTION METHODS FOR TANKS
-------
SLIDE IV-2
ALLOWABLE LEAK DETECTION METHODS
Monthly leak detection methods
- Automatic tank gauging
-- Manual tank gauging
-- Secondary containment with interstitial monitoring
-- Ground-water monitoring
-- Vapor monitoring
Inventory control and tank tightness testing
-------
SLIDE IV-3
REQUIREMENTS FOR LEAK DETECTION FOR UST TANKS
There are different leak detection deadlines for new and
existing UST tanks:
New tank deadlines
-- MUST comply with UST leak detection when
installed
Existing tank deadlines
-- must comply with the requirements according to
the following timetable (next slide):
-------
SLIDE IV-4
AGE OF TANK
Existing Tanks
Installed:
Before 1965 or
unknown
1965-1969
1970-1974
1975-1979
1980-1988
LEAK DETECTION
Must have leak detection
by:
December 1 989
December 1990
December 1991
December 1992
December 1993
-------
SLIDE IV-5
LEAK DETECTION FOR NEW TANKS
Monthly monitoring (ATGS, manual tank gauging,
secondary containment with interstitial monitoring,
ground-water monitoring, vapor monitoring)
Monthly inventory control and tank tightness testing
every five years. (This choice can be used only for
ten years after installation)
-------
SLIDE IV-6
LEAK DETECTION FOR EXISTING TANKS
Monthly monitoring
Monthly inventory control and tank tightness testing
every five years. (Can be usved for only ten years
after adding corrosion protection and spill/overfill
prevention or until December 1998, whichever date is
later)
Monthly inventory control and annual tank tightness
testing (this can be used only until December 1 998)
-------
SLIDE IV-7
PD/PFA REQUIREMENTS
Some methods must be capable of detecting a
specified leak rate or quantity with a probability of
detection (PD) of 0.95 and a probability of false alarm
(PFA) of 0.05
By December 1990, automatic tank gauging systems
and tightness tests for tanks or piping must meet
PD/PFA requirements
By September 1991, automatic line leak detectors
must meet PD/PFA requirements
-------
SLIDE IV-8
LEAK DETECTION METHODS -- MONTHLY MONITORING
Five monthly monitoring methods:
Automatic tank gauging
Manual tank gauging
Secondary containment with interstitial monitoring
Ground-water monitoring
Vapor monitoring
-------
SLIDE IV-9
FOR EACH RELEASE DETECTION METHOD
Brief description of how the method works
When the method is appropriate
Considerations for owners/operators
-------
SLIDE IV-10
HOW AUTOMATIC TANK GAUGING SYSTEMS WORK
Continuously measure and record product level and
temperature in tank
Measure volume change over time. If it decreases
significantly, there may be a leak
-------
SLIDE IV-11
SCHEMATIC OF AN AUTOMATIC TANK GAUGING SYSTEM
REMOTE ATG MONITOR
PUMP OR PUMP
CONTROL CONSOLE
FILL PIPE
(OPTIONAL WIRING)
-------
SLIDE IV-12
HOW AUTOMATIC TANK GAUGING SYSTEMS WORK
Inventory control mode
Leak testing mode
-------
SLIDE IV-13
GENERAL PROCEDURE FOR ATGS
I
N
S
T
A
L
L
A
T
I
0
N
Install equipment
- Probes in tanks
- Monitor nearby
Program monitor
- Tank depth and volume chan
- Test times
- Alarm levels
Shutdown tank operations
TESTING
OR
INVENTORY
- Temperature to reach
equilibrium
- Tank deformation to sut
Make temperature
and level
measurements
\
TESTING
A
N
A
L
Y
S
I
S
Reconcile
inventory data
Apply
detection
criteria
-------
SLIDE IV-14
HOW AUTOMATIC TANK GAUGING SYSTEMS WORK
Inventory control mode
Automatically records activities of an in-service tank,
including deliveries
-- Product level and temperature readings are
automatically taken and are converted to volume
measurements. Data used in inventory control
-- ATGS operate in this mode when leak test is not
being performed
-------
SLIDEIV-15
ATGS ALARM SYSTEMS
ATGS alarms notify owners/operators of:
-- High and low product levels
- High water level
Theft of product
-------
SLIDE IV-16
HOW AUTOMATIC TANK GAUGING SYSTEMS WORK
Leak testing mode
Product level and temperature measured generally at
least two hours a month while tank not in use
Determines change in volume per hour, compares
that value to an internal standard, and determines if
UST is leaking or not
Test can be run at any level of product in tank
Tank must be out of service during the test
-------
SLIDE IV-17
WHEN ATGS ARE APPROPRIATE
UST system characteristics
-- Primarily used for tanks with capacity less than
15,000 gallons and cannot be used for piping
Product characteristics
-- Primarily used with gasoline or diesel
- If used with larger size or other fuels, ask vendor
for proof that the method is effective
Soil conditions
-- No restrictions exist
-------
SLIDE IV-18
WHEN ATGS ARE APPROPRIATE
Climatic factors
-- Following delivery of fuel there is a six-hour
waiting period (or longer, depending on climate)
Geologic conditions
-- Ground water covering all or part of a tank may
mask a leak
-------
SLIDE IV-19
EFFECT OVER TIME OF TOPPING THE TANK WITH
COLDER PRODUCT
O>
O
TJ
i
O
o>
a
O
£
»*
2
o
a.
o>
0.50
0.40
0.30
0.20 -
0.10 -
0.00
214
11
TIme-h
-------
SLIDE IV-20
THE EFFECT OF GROUND WATER ON THE
RATE OF FLOW THROUGH A HOLE
IN AN UST
Water table above level of
leak. Ground water enters
tank through hole.
Water
Table
Water table below level of tank.
Product escapes from hole.
Water Table
-------
SLIDE IV-21
CONSIDERATIONS
Tank level
No product should be delivered to tank for at least
six hours before the monthly test
No product should be withdrawn from the tank for a
few hours before the monthly test
No product can be withdrawn from or added to an
UST during the monthly test, which lasts one to six
hours
-------
SLIDE IV-22
CONSIDERATIONS
ATGS requires little staff time
Some owners/operators find inventory control and
optional off-site monitoring features attractive
Tanks require a dedicated opening for the ATGS
probe, making retrofit difficult in some cases
-------
SLIDE IV-23
HOW MANUAL TANK GAUGING WORKS
Short-term test in a static UST system
This test differs from inventory control, which
requires daily recording volume in an active tank
Method cannot be used on tanks larger than 2,000
gallons
-------
SLIDE IV-24
HOW MANUAL TANK GAUGING WORKS
Product measured weekly with gauge stick
Test lasts up to 58 hours, depending on tank size
UST must be out-of-service during the test
Four measurements taken each week
-- Two at beginning of the test
- Two at end of the test
-------
SLIDE IV-25
SAMPLE CALIBRATION CHART CONVERTING
PRODUCT DEPTH TO GALLONS*
^\Tank Size
Depth^^^
in Inches ^\^
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
550 Gal.
491/2" x 5'5"
2
7
13
20
29
37
47
57
68
79
90
102
115
127
140
1000 Gal.
491/2Mx 10'
4
13
24
38
52
68
86
104
124
144
165
187
209
232
255
1000 Gal.
64" x 6'
3
9
17
26
36
47
59
72
85
100
114
130
145
162
178
1500 Gal.
64" x 9'
4
13
25
39
54
71
89
108
128
150
172
195
218
243
268
2000 Gal.
64" x 12'
6
18
34
52
75
94
119
144
171
200
229
260
291
324
357
* Note that product depth in left column converts to gallons in the other
columns.
-------
SLIDE IV-26
HOW MANUAL TANK GAUGING WORKS
Calibrations converted to product volume
Average of first two measurements - Average of final
two measurements = Change in product volume over
time
Compare calculated tank volume change to weekly
and monthly standards to determine whether
discrepancy indicates leak
-------
SLIDE IV-27
WEEKLY AND MONTHLY STANDARDS
FOR VOLUME CHANGE
Tank Weekly
Capacity Change
(gal.) (gal.)
Up to 550 10
551 - 1 ,000 (64"x73") 9
1,000(48"x128") 12
If MTG is combined with TTT:
1 ,001 - 2,000 26
Monthly
Standard
(gai.)
5
4
6
13
Test
Duration
(hrs.)
36
44
58
36
-------
SLIDE IV-28
WHEN MANUAL TANK GAUGING IS APPROPRIATE
UST system characteristics
Used only with tanks with capacity less than 2,001
gallons
-- Tanks smaller than 1 ,001 gallons may use this
method alone for the life of the tank
-- Tanks between 1 ,001 and 2,000 gallons must also
use periodic tank tightness testing. Combined
method can be used only for ten years following
installation or upgrade. Not allowed after 1998 for
existing, non-upgraded tanks
-------
SLIDE IV-29
WHEN MANUAL TANK GAUGING IS APPROPRIATE
Product characteristics
Not restricted
Works best with heavier fluids (e.g., used oil)
Soil conditions
Not restricted
-------
SLIDE IV-30
WHEN MANUAL TANK GAUGING IS APPROPRIATE
Climatic factors
Ambient temperature changes may affect volume of
stored product
If temperature change is great, testing period can be
lengthened
-------
SLIDE IV-31
WHEN MANUAL TANK GAUGING IS APPROPRIATE
Geologic conditions
Ground water may mask leak
Should not be used in areas with permanent high
water table
-------
SLIDE IV-32
CONSIDERATIONS
Frequency and length of test
- Test must be performed at least once a week
-» Testing period must last at least 36 hours
-- Owner/operator must remove UST system from
service during test
Equipment costs are very low
-------
SLIDE IV-33
HOW SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING WORKS
Secondary containment provides a barrier between
tank and surrounding environment
Interstitial monitors test for product in space between
tank and outer containment barrier
-------
SLIDE IV-34
TANKS IN A CONCRETE VAULT
MAYOR
MAY NOT H
BE
BACKFILLED
CONCRETE OR
ASPHALT SURFACE
CONCRETE
INTERIOR
LINING
SUMP
SINGLE WALL TANK
-------
SLIDE IV-35
TWO DOUBLE-WALLED TANK
CONFIGURATIONS
Sampling
Standpipe
or
Electronic
Detection
\
Out* Wail
inrwr Wall
OouWe-Walled Steel Tank
Interstitial Space
^ Illlllllll
Doubto-Wafled FRP Tank
-------
SLIDE IV-36
TANK WITH EXCAVATION LINER
Monitoring Point Suitable
for Leak Detection and
Withdrawal of Accumulated
Water
Pavement
Trench Top Liner
Pipe Leak
Detection
Monitoring
Point
Collar to Connect
Pipe Trench to
Tank Liner
Tank
Excavation
Liner
Some
Partially
Enclosed Liners
Would End Here
Trench Liner
Interstitial Space
Slotted Pipe for
Leak Detection and
Withdrawal of Water
Native Soil
-------
SLIDE IV-37
INTERSTITIAL MONITORING METHODS INCLUDE
Electrical conductivity
Pressure sensing
Liquid sensors
Hydrostatic sensing
Manual detection (dipstick)
Vapor monitoring
-------
SLIDE IV-38
DOUBLE-WALLED TANK SHOWING PLACEMENT OF
BOTH VAPOR AND LIQUID SENSORS
Liquid Sensor
-------
SLIDE IV-39
WHEN SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING IS APPROPRIATE
UST system characteristics
Can be used for both tanks and piping
Double-walled tanks are seldom larger than 20,000
gallons
Excavation liners may be used around any size tank
* Secondary containment is not practical for existing
tanks and piping, except when an internal bladder is
used for existing tanks
-------
SLIDE IV-40
WHEN SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING IS APPROPRIATE
Product characteristics
Methods may be used for all fuel types, including
hazardous substances
Soil conditions
No restrictions exist
-------
SLIDE IV-41
WHEN SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING IS APPROPRIATE
Climatic factors
No restrictions. However, in areas with heavy rainfall
a fully enclosed containment system should be used
Geologic conditions
In areas of high ground water, a fully enclosed
containment system should be used
-------
SLIDE IV-42
CONSIDERATIONS
Difficult installation
Installation of secondary containment using liners
requires even more careful attention by professional
installers than other leak detection methods
With the exception of internal bladders, retrofitting is
basically impractical because it requires removing
tank and piping entirely, installing a liner, and
reinstalling tank
-------
SLIDE IV-43
CONSIDERATIONS
Compatibility of barrier with stored product
Exposure to product should not result in deterioration
of barrier
For standard petroleum products such as gasoline
and diesel fuel, most liners sold are compatible with
product
For products other than petroleum, nature of product
and type of barrier must be considered to ensure an
appropriate match
-------
SLIDE IV-44
CONSIDERATIONS
Barrier may protect environment if leak occurs.
Low, if any, corrective action costs associated with this
method. This aspect differentiates this method from
others by detecting leaks and containing them
-------
SLIDE IV-45
HOW GROUND-WATER MONITORING WORKS
Monitoring wells
There are generally one to four wells per UST
Wells must be placed in, or near, backfill so that they
can detect leaks rapidly
Well screen extends from the bottom of well to the
highest water table level
On-site staff must check wells at least monthly for
presence of leaked product floating on ground-water
surface
-------
SLIDE IV-46
MONITORING WELLS WITH FILTER PACK
GROUND SURFACE
WELL CAP
VENT HOLE
BENTONITE OR
CEMENT GROUT
WATER TABLE
WELL SCREEN
BOTTOM
CASINO PLUG
PROTECTIVE STEEL
CASING
ANNULAR SEAL
FILTER PACK
-------
SLIDE IV-47
MONITORING WELL IN EXCAVATION ZONE
Monitoring Well
Water Table
Surface
Pavement
Well Screen
Free Product Layer
Product/Water Contact
_J
Perimeter of Tank
Excavation
Monitoring wells installed in the excavation
zone will quickly detect a release when the
ground water table is within the tank
excavation.
-------
SLIDE IV-48
THE WELL SCREEN IS PLACED TO EXTEND
OVER THE ENTIRE RANGE OF WATER
TABLE FLUCTUATION
SCREENED RANG! -
OftOUNO SURFACE
High Water Table
HANOI OP WATIMTAftLI
FLUCTUATION
Low Water Table
-------
SLIDE IV-49
MONITORING WELLS
In manual systems, ground-water samples must
be collected from the well by hand with a bailer at
least once a month
In automatic systems, the detector operates by
itself and sounds an alarm. This system is used
at least once per month
-------
SLIDE IV-50
HOW GROUND-WATER MONITORING WORKS
Manual Devices
Grab samplers
Chemical-sensitive pastes
-------
SLIDE IV-51
HOW GROUND-WATER MONITORING WORKS
Types of automatic devices
Differential float devices
Product soluble devices
Thermal conductivity devices
Electrical conductivity devices
-------
SLIDE IV-52
SCHEMATIC OF A DIFFERENTIAL
FLOAT DEVICE
Monitor
Reinforced Concrete Slab
Over Tank
Bottom Alignment Spacer
X
Top Alignment Spacer
Monitoring Wefl
Bottom Locking Nut
-------
SLIDE IV-53
SCHEMATIC OF A MECHANICALLY
ACTIVATED PRODUCT
SOLUBLE DEVICE
Ground Surface
Spring Loaded Indicator
Monitoring '/,
^Groundwaterx
glablc
-------
SLIDE IV-54
SCHEMATIC OF THERMAL
CONDUCTIVITY DEVICE
Monftodnf Wtil -».
-------
SLIDE IV-55
WHEN GROUND-WATER MONITORING IS APPROPRIATE
UST system characteristics
Can be used to detect leaks from both tanks and
pipes
May be used on any size tank. For larger systems,
more wells are added
May be retrofitted
-------
SLIDE IV-56
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Product characteristics
Density must be lower than that of water
Product should not mix easily with water
Two examples are gasoline and diesel fuel
-------
SLIDE IV-57
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Soil conditions
Soil or backfill between well and UST must be
permeable
Soil or backfill must be porous enough to allow
released product to travel to wells
Hydraulic conductivity should be > 0.01 cm/sec
-------
SLIDE IV-58
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Climatic factors
Very low temperatures can cause incorrect test
results. Ice can freeze monitors and interfere with
product-soluble devices
-------
SLIDE IV-59
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Geologic conditions
Level of ground-water table must be less than 20 feet
from the surface
Fluctuations in water table level may restrict use
Gradient of ground-water flow must be known for
effective placement of monitoring wells
Well placement must account for fractures and
cavities in the soil
-------
SLIDE IV-60
POORLY PLACED GROUND-WATER
MONITORING WELL
Product-Filtod
Fractures
Not*: No Fre« Product in Well
Fractured Rock
Karstic Limestone
-------
SLIDE IV-61
CONSIDERATIONS
Site assessment is necessary
Operation of detection devices is simple
Avoid damage to tanks and pipes during installation
-------
SLIDE IV-62
HOW VAPOR MONITORING SYSTEMS WORK
Check for presence of product fumes near UST
system
Automatic systems incorporate network of sensors
Manual systems use air samples collected from a
network of wells
-------
SLIDE IV-64
UNDERGROUND STORAGE TANK SYSTEM WITH
VAPOR MONITORING WELLS
VAPOR
MONTTORM4G
DEVICE
VAPOR
MOMTORMG
WELL
-------
SLIDE IV-65
MAP VIEW OF TYPICAL UST SITE
WITH VAPOR MONITORING
PUMP
PUMP
PUMP
VAPOR WELL IN
PRODUCT LINE BACKFILL
PRODUCT LINES
BACKGROUND VAPOR WELL
VAKMWEU.
MTANKSACKnU.
/ 10* RADIUS OF
/ INFLUENCE FOR WELLS
-------
SLIDE IV-66
WHEN VAPOR MONITORING IS APPROPRIATE
UST system characteristics
Can be used for both tanks and piping
Can be installed with new or existing tanks and
piping
-------
SLIDE IV-67
WHEN VAPOR MONITORING IS APPROPRIATE
Product characteristics
Must be used with products that vaporize readily
(e.g., gasoline)
-------
SLIDE IV-68
WHEN VAPOR MONITORING IS APPROPRIATE
Soil conditions
Backfill around tank must allow the passage of
vapors
Soil should be clean and should not contain
substances that will produce vapors
-------
SLIDE IV-69
THE EFFECT OF SOIL ON VAPOR
CONCENTRATIONS AT A WELL
8000
6000 -
I
I
uooo -
2000-
Dry gravel backfill
Dry sIKy sand
Moist sand backfill
Wet sand or clay
10 20
Number of Days
-------
SLIDE IV-70
WHEN VAPOR MONITORING IS APPROPRIATE
Climatic factors
Temperature affects the volatility of released product
This method should not be used in areas with heavy
annual rainfall or extremely moist climates
Water fills spaces between soil particles
Vapors may dissolve in the moisture
Heavy rains may fill wells with water and drown
sensors if not properly capped and sealed
-------
SLIDE IV-71
WHEN VAPOR MONITORING IS APPROPRIATE
Geologic conditions
This method should not be used in areas with high
groundwater, which interferes with vapor detection
-------
SLIDE IV-72
CONSIDERATIONS
Manual monitoring systems require monthly time
investments
-- Large sites require considerable time each month
-- Samples are often sent off-site for analysis
Spill/overfill protection needed
-------
SLIDE IV-73A
HOW SIR WORKS
Daily measurements of product level in tank combined
with complete records of all withdrawals from the UST
and deliveries to the UST
SIR vendor uses sophisticated statistical software to
conduct computerized analysis of data
SIR vendor provides monthly reports that can identify if
UST is leaking
-------
SLIDE IV-73B
HOW SIR WORKS
SIR must be done monthly and meet the PD/PFA and
minimum detectable leak rate (0.2 gallons per hour)
Monthly SIR results must be available at the UST facility
SIR can qualify as a tank tightness test if it meets Federal
requirements for PD/PFA and minimum detectable leak rate
(0.1 gallons per hour)
-------
SLIDE IV-73C
WHEN SIR IS APPROPRIATE
UST system characteristics
- Primarily used for tanks with capacity less than
18,000 gallons
Product characteristics
- Generally not restricted by product type
Soil conditions
-- No restrictions exist
-------
SLIDE IV-73D
WHEN SIR IS APPROPRIATE
Climatic factors
-- Temperature changes affect data, so SIR vendors must
take climatic factors into consideration
Geologic conditions
-- Ground water covering all or part of a tank may mask a
leak or distort the data
-------
SLIDE IV-73E
CONSIDERATIONS
SIR can be used for tank and piping
SIR is a very sophisticated statistical analysis that must
meet Federal requirements
SIR requires the use of good inventory measurement
practices
-------
SLIDE IV-73F
CONSIDERATIONS
Data can be sent to SIR vendor on paper or using computer
modems or diskettes
SIR can identify leaking systems, miscalibrated meters,
tilted tanks, and loss resulting from theft
SIR requires minimal investment of staff time and
equipment costs; overall costs compare favorably to other
methods
State and local governments can place restrictions on SIR
use
-------
SLIDE IV-74
COMBINATION METHOD
Inventory control must be combined with tank
tightness testing
This combined method can be used only for ten
years following new tank installation or existing tank
upgrade
-------
SLIDE IV-75
INVENTORY CONTROL
How inventory control works
Daily accounting system is used
Tank volume, deliveries, and sales are recorded daily
Accounts of deliveries and product sold from tank are
compared with daily volume measurements
Overage/shortage determined monthly
-------
SLIDE IV-76
HOW INVENTORY CONTROL WORKS
Daily tank gauging and reconciling
Measure product level with a gauge stick marked to
one-eighth of an inch
Translate level of product from gauge to volume of
product in tank, using manufacturer calibration chart
Record product volume and day's withdrawals and
receipts on ledger form
-------
SLIDE IV-77
HOW INVENTORY CONTROL WORKS
Gauge stick must be inserted through fill pipe until it
touches bottom of tank
-------
SLIDE IV-78
SAMPLE CALIBRATION CHART CONVERTING PRODUCT
DEPTH TO GALLONS*
^\Tank Size
Deptn^-x^
in Inches ^x^
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
550 Gal.
49V2" x 5'5"
2
7
13
20
29
37
47
57
68
79
90
102
115
127
140
1000 Gal.
491/2"x 10'
4
13
24
38
52
68
86
104
124
144
165
187
209
232
255
1000 Gal.
64" x 6'
3
9
17
26
36
47
59
72
85
100
114
130
145
162
178
1500 Gal.
64" x 9'
4
13
25
39
54
71
89
108
128
150
172
195
218
243
268
2000 Gal.
64" x 12'
6
18
34
52
75
94
119
144
171
200
229
260
291
324
357
2500 Gal.
64" x 15'
8
23
42
65
90
118
148
180
214
250
287
325
364
495
447
3000 Gal.
64"x^8'
9
27
51
78
108
142
178
217
257
300
344
390
437
486
536
4000 Gal.
64" x 24'
13
37
68
104
145
189
238
289
343
400
459
520
583
648
715
* Note that product depth in left column converts to^albns in the other columns.
-------
SLIDE IV-79
PART OF A MONTHLY
RECONCILIATION FORM
LINE
1
2
3
4
DAY
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Cum. Over Total
% Thru.
Cum. Short. Total
% Thru.
REGULAR
UNLEADED
Attention: The cumulative sum of monthly overages or shortages should not exceed
1.0% of the monthly throughput plus 130 gallons.
-------
SLIDE IV-80
MONTHLY RECONCILIATION
(INVENTORY CONTROL)
Monthly reconciliation
At least monthly, daily product volume data are
reconciled with delivery and withdrawal amounts
If overage/shortage is greater than or equal to 1.0
percent of tank's flow-through volume plus 130
gallons of product, UST may be leaking
-- If this occurs over two consecutive months,
owner/operator must report results to local
implementing agency as possible leak
-------
SLIDE IV-81
HOW INVENTORY CONTROL WORKS
Tank stock control
Dispensing meters must be correctly calibrated
Product delivery volumes must be verified
Unaccounted for additions and withdrawals must be
included in reconciliation
-------
SLIDE IV-82
GENERAL PROCEDURE FOR
INVENTORY CONTROL
Testing
Analysis
Tank Gauging
Product gauge
Water gauge
Calibration
Volume of product determined
from calibration chart
Tank Stock Control
Withdrawals
Receipts
Recording & Reconciliation
Interpretation
Leak
No Leak
-------
SLIDE IV-83
WHEN INVENTORY CONTROL IS APPROPRIATE
UST system characteristics
Applicable for any size UST as long as performance
standard of 1.0 percent flow-through plus 130 gallons
is met
-------
SLIDE IV-84
WHEN INVENTORY CONTROL IS APPROPRIATE
Product characteristics
Effective for diesel and gasoline fuels and products
with similar viscosities and thermal properties
For other products, make sure this method can be
used satisfactorily with those substances
Soil conditions
Are not a factor
-------
SLIDE IV-85
WHEN INVENTORY CONTROL IS APPROPRIATE
Climatic factors
Ambient air and ground temperatures can affect
measured product volume
Temperature difference between newly-delivered
product and product in tank limits accuracy
-------
SLIDE IV-86
WHEN INVENTORY CONTROL IS APPROPRIATE
Geologic conditions
High ground water may interfere with testing
-- This method may be inappropriate for areas with
permanent high ground water
Monthly measurement using a gauge covered with
water-finding paste must be taken to identify any
water in tank, and accounted for in reconciliation
-------
SLIDE IV-87
CONSIDERATIONS
Must be combined with periodic tank tightness tests
Regular calibrations and calculations
Staff time
Small leaks can go undetected for a long period
Used only with metered storage tanks
Deliveries made through drop tube extending to
within one foot of tank's bottom
-------
SLIDE IV-89
FACTORS AFFECTING INVENTORY CONTROL RESULTS
Temperature variation
Meter calibration accuracy
Tank volume/calibration chart discrepancy
Delivery overage or shortage
Theft
* Tank tilt
-------
SLIDE IV-91
HOW TANK TIGHTNESS TESTING WORKS
Identifies leaks in closed tank systems
-- Volumetric tests
-- Non-volumetric tests
-------
SLIDE IV-92
HOW TANK TIGHTNESS TESTING WORKS
Volumetric Testing
Changes in product level or volume in tank are
measured precisely (in milliliters or thousandths of an
inch) over several hours
Changes in product temperature must also be
measured to account for temperature-induced
changes in product level
Net decrease in product volume during test indicates
leak
-------
SLIDE IV-93
TEMPERATURE AND LEVEL GAUGES
TEMPERATURE
LEVEL
-------
SLIDE IV-95
COMPARISON OF PARTIALLY-FILLED
AND OVERFILLED TANKS
Partially-Filled Tank
Overfilled Tank
Large volume changes produce
only very small level changes
A small volume change can
produce a drastic level change
-------
SLIDE IV-96
HOW TANK TIGHTNESS TESTING WORKS
Non-volumetric testing
Negative pressure (vacuum) is placed in tank.
Equipment "listens" for small air bubbles
Tracers that will escape from a leak and be detected
in the backfill can be added to the product
-------
SLIDE IV-97
HOW TEMPERATURE CHANGES CAN BE
MISTAKEN FOR A LEAK
CAP
CONCRETE
CAP
CONCRETE
PRODUCT LEVEL
FILL TUBE PRODUCT LEVEL
NEW, COOLER PRODUCT
OLD PRODUCT
(A) A tank has just had additional
product added.
FILL TUBE
MIXED, STABILIZED PRODUCT
(B) After several hours, product
mixture has stabilized
temperature, resulting in lower
product level.
-------
SLIDE IV-98
HOW STRUCTURAL DEFORMATION OF THE TANK
CAN BE MISTAKEN FOR A LEAK
PRODUCT LEVEL
FILL TUBE
PRODUCT
PRODUCT LEVEL
FILL TUBE
PRODUCT
(A) An empty underground tank has just
been filled with product
(B) In response to the pressure and/or
temperature of the product, the ends
of the tank begin to deflect (structural
deformation), and the level of the
product goes down.
-------
SLIDE IV-99
WHEN TANK TIGHTNESS TESTING IS APPROPRIATE
UST system characteristics
- Test tanks smaller than 15,000 gallons
-- If system is automated, up to four tanks may be
tested at one time
-- Piping may be tested similarly
Product characteristics
- Primarily used in tanks containing gasoline,
diesel, and light heating oils
-------
SLIDE IV-100
WHEN TANK TIGHTNESS TESTING IS APPROPRIATE
Soil conditions
-- Uncompacted backfill causes tank end deflection
Climatic factors
- Volumetric testing requires stable product
temperature
Geologic conditions
-- Ground water level must be determined
- Presence of ground water may mask an actual
leak
-------
SLIDE IV-101
CONSIDERATIONS
Must be used with inventory control
Tank must be taken out of service during test
Permanent installation of equipment unnecessary
Many different commercial methods are available
Tester must follow proper testing methods
-------
SLIDE IV-102
HOW DO I SELECT THE RIGHT LEAK DETECTION
METHOD FOR A SPECIFIC UST?
Deadlines for compliance
Monthly leak detection
- Automatic tank gauging
- Manual tank gauging
- Secondary containment with interstitial monitoring
-- Ground-water monitoring
-- Vapor monitoring
-- Statistical inventory reconciliation
Inventory control and tank tightness testing
-------
CHAPTER V-1
LEAK DETECTION METHODS FOR UST PIPING
-------
SLIDE V-2
WHAT DO I NEED TO KNOW ABOUT UST PIPING
MONITORING AND LEAK DETECTION?
UST piping
Leak detection requirements for UST piping
Leak detection methods
-------
SLIDE V-3
PRESSURIZED PIPING SYSTEMS
Product is pushed through a pump in bottom of tank
Very large releases can occur quickly at a break
Systems are usually chosen for high volume sites
-------
SLIDE V-4
SUCTION PIPING SYSTEMS
A positive displacement pump creates a vacuum
which draws product from the tank to the pump
If a leak in the lines occurs, suction is interrupted,
and product flows back through the piping toward the
tank
-------
SLIDE V-5
AMERICAN AND EUROPEAN PIPING SYSTEMS WITH
CHECK VALVES
American System
European System
Check Valve
-------
SLIDE V-6
LEAK DETECTION FOR UST PIPING
Deadlines
Requirements
Methods
-------
SLIDE V-7
PRESSURIZED PIPING DEADLINES
New pressurized piping: must comply with UST leak
detection requirements when installed
Existing pressurized piping: must comply with UST
leak detection requirements by December 1990
-------
SLIDE V-8
SUCTION PIPING DEADLINES
No leak detection is required for new or existing
"European" style piping
-- Adequate slope
-- One check valve
New "American" style suction piping must comply
with UST leak detection requirements when installed
Existing "American" style suction piping must comply
with UST leak detection requirements according to
the following timetable
-------
SLIDE V-9
Installation Must Comply
Date By
Before 1965* December 1989
1965 -1969 December 1990
1970 -1974 December 1991
1975 -1979 December 1992
1980 -1988 December 1993
Or if installation date is unknown
-------
SLIDE V-10
PRESSURIZED PIPING SYSTEM
Gas Pump Ga» PuP
Line Leak
Detector
-------
SLIDE V-11
REQUIREMENTS FOR PRESSURIZED PIPING
Pressurized piping (new and existing)
Each pressurized piping run must have an automatic
line leak detector (LLD)
Pressurized piping must also have one of the
following:
-- Monthly ground-water monitoring
-- Monthly vapor monitoring
-- Monthly interstitial monitoring
- Annual tightness test
-------
SLIDEV-12
SUCTION PIPING REQUIREMENTS
If new and existing suction piping requires leak detection,
then one of the following four methods must be used
Line tightness testing (every three years)
Ground-water monitoring
Vapor monitoring
Secondary containment with interstitial monitoring
-------
SLIDE V-13
AUTOMATIC LINE LEAK DETECTORS
Automatic flow restrictor
Automatic shutoff device
-------
SLIDE V-14
LEAK DETECTION METHODS
Automatic line leak detectors
Line tightness testing methods
Monthly monitoring methods
-------
SLIDE V-15
REQUIREMENTS FOR PD/PFA
Line tightness testing must meet the requirements for
the probability of detection and false alarm (PD/PFA)
by December 1990
Automatic line leak detectors must meet the PD/PFA
requirements by September 1991
-------
SLIDE V-16
HOW AUTOMATIC FLOW RESTRICTORS WORK
Mechanical devices installed directly in the piping or
pump housing
When pressure in the pump delivery system drops
below a certain threshold, a test is automatically
performed
Devices trigger an alarm when a leak is detected
-------
SLIDEV-17
HOW AUTOMATIC FLOW RESTRICTORS WORK
Restrictors reduce flow of product when there is a
leak
Restrictors limit product flow to 3 gallons per hour
-------
SLIDE V-18
WHEN AUTOMATIC FLOW
RESTRICTORS ARE APPROPRIATE
Use only for pressurized piping
Most gas station USTs already have automatic flow
restrictors
-------
SLIDEV-19
CONSIDERATIONS
Causes slight lag in product delivery when properly
operating
On-site staff may tamper with system to avoid delays
in product delivery
Requires little owner/operator involvement
-------
SLIDE V-20
AUTOMATIC FLOW SHUTOFF
Two different types of automatic flow shutoff
devices
-- Pressure increase monitor
-- Pressure decrease monitor
-------
SLIDE V-21
HOW AUTOMATIC FLOW SHUTOFF DEVICES WORK
Pressure Increase Monitor
Normal rate of pressurization in pipes is calculated
The rate of increase in line pressure is measured
when pump is activated
If there is a leak, it will take longer for the piping to
become fully pressurized
The system shuts down automatically
-------
SLIDE V-22
HOW AUTOMATIC FLOW SHUTOFF DEVICES WORK
Pressure Decrease Monitor
System monitors line pressure over several minutes
when dispenser is not in use
A leak is indicated if:
-- Constant pressure can not be maintained
-- Pressure decreases more quickly than its normal
rate
-------
SLIDE V-23
WHEN SHUTOFF DEVICES ARE APPROPRIATE
Used for pressurized piping only
-------
SLIDE V-24
CONSIDERATIONS
Devices are subject to tampering if they are not
locked or tamper-proofed in some way
Test cannot be run while dispensers are in use
Devices provide nearly continuous leak detection and
require little time from staff
-------
SLIDE V-25
LINE TIGHTNESS TESTING
Direct volumetric line tightness test
Indirect line tightness test
-------
SLIDE V-26
HOW THE DIRECT VOLUMETRIC LINE
TIGHTNESS TEST WORKS
Tests the ability of UST piping to maintain a specified
pressure
A hand pump or the dispenser and the submerged
pump is used to pressurize the piping leading back to
the tank
The amount of volume lost is determined
If a certain volume of product is lost, a leak is
indicated
-------
SLIDE V-27
WHEN THE DIRECT VOLUMETRIC
LINE TIGHTNESS TEST IS APPROPRIATE
It is practical when performed in conjunction with
tank testing
Line tightness testing may be performed on both
pressurized and suction systems
-------
SLIDE V-28
CONSIDERATIONS
Line must be shut down for several hours for the test
Test requires no permanent equipment
Test can conveniently be performed along with tank
tightness testing
Test needs to be performed only once every three
years for suction piping
Problems are due to poor fittings and gaskets, vapor
pockets, bad check valves, etc.
-------
SLIDE V-29
HOW THE INDIRECT LINE TIGHTNESS TEST WORKS
Piping is tested as a part of a full tank system test
Procedures are the same as for tank tightness with
the following additions:
-- Overfill methods must be used
-- If test finds no leaks, both tank and lines are
assumed to be intact
-- If tank is leaking, separate test of piping must be
conducted
-------
SLIDE V-30
WHEN THE INDIRECT LINE
TIGHTNESS TEST IS APPROPRIATE
Indirect line tightness tests must be done in
conjunction with tank testing; tanks and piping may
be on different test schedules
Line tightness testing may be performed on both
pressurized and suction systems
-------
SLIDE V-31
CONSIDERATIONS
Lines must be shut down for at least several hours
Test must be performed only once every three years
for suction piping (annually for pressurized piping)
After filling the line, tester should wait for three hours
before beginning data collection
Vapor pockets can inhibit effective testing
-------
SLIDE V-32
SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING
Methods, considerations, and applications of
interstitial monitoring with secondary containment for
piping systems are similar to those for tanks
Use trench liners or double-walled piping
-------
SLIDE V-33
HOW SECONDARY CONTAINMENT WITH INTERSTITIAL
MONITORING WORKS
For trench liners
Backfill and piping are placed in a lined trench
Trench should be sloped away from the tank
excavation to differentiate between tank leaks and
piping leaks
An interstitial monitor is placed between piping and
the trench liner
-------
SLIDE V-34
HOW SECONDARY CONTAINMENT WITH INTERSTITIAL
MONITORING WORKS
For double-walled piping
Piping that carries the product is contained within a
larger outer pipe
Monitor is placed in sump or between inner and outer
pipes
-------
SLIDE V-35
WHEN SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING IS APPROPRIATE
UST system characteristics
Can be used for both tanks and piping
Secondary containment is not practical for existing
piping
-------
SLIDE V-36
WHEN SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING IS APPROPRIATE
Product characteristics
Methods may be used for all fuel types, including
hazardous substances
Soil conditions
No restrictions exist
-------
SLIDE V-37
WHEN SECONDARY CONTAINMENT WITH
INTERSTITIAL MONITORING IS APPROPRIATE
Climatic factors
No restrictions. However, in areas with heavy rainfall
a fully enclosed containment system should be used
Geologic conditions
In areas of high ground water, a fully enclosed
containment system should be used
-------
SLIDE V-38
CONSIDERATIONS
Correct installation is essential
Monitoring can often be integrated with the tank
monitoring system
Prevents environmental contamination and reduces
potential for cleanup costs
-------
SLIDE V-39
GROUND-WATER MONITORING
How does ground-water monitoring work?
Use of this method for piping is generally the same
as its use for tanks
Additional wells are needed every 10 to 20 feet of
piping run
-------
SLIDE V-40
WHEN GROUND-WATER MONITORING IS APPROPRIATE
UST system characteristics
Ground-water monitoring can be used to detect leaks
from both tanks and piping
Ground-water monitoring may be used on any
size piping run. For larger systems, more wells
are added
May be retrofitted on existing tanks and piping
-------
SLIDE V-41
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Product characteristics
Density must be lower than that of water
Product should not mix easily with water
Two examples are gasoline and diesel fuel
-------
SLIDE V-42
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Soil conditions
Backfill between well and LIST must be permeable
Soil or backfill must be porous enough to allow
released product to travel to wells
Hydraulic conductivity should be more than 0.01
cm/sec
-------
SLIDE V-43
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Climatic factors
Very low temperatures may interfere. Ice can freeze
monitors and interfere with product-soluble devices
-------
SLIDE V-44
WHEN GROUND-WATER MONITORING IS APPROPRIATE
Geologic conditions
Level of ground-water table must be no more than 20
feet below the surface
Fluctuations in water table level must be taken into
account
Gradient of ground-water flow must be taken into
account
-------
SLIDE V-45
CREVICES AND FRACTURES
Product-Filled
Fractures
V
Water-Filled
Fractures
Note: No Free Product in Well
Fractured Rock
Karstic Limestone
-------
SLIDE V-46
CONSIDERATIONS
Site hydrogeological assessment is needed
Operation of detection devices is simple
Can be integrated with tank ground-water monitoring
system
Avoid damage to pipes during installation
-------
SLIDE V-47
VAPOR MONITORING
Use of this method for piping is generally the same
as its use for tanks
Wells used for piping monitoring can be shallower
than those used for tank monitoring
-------
SLIDE V-48
WHEN VAPOR MONITORING IS APPROPRIATE
UST system characteristics
Can be used for both tanks and piping
Can be installed with new or existing tanks and
piping
-------
SLIDE V-49
WHEN VAPOR MONITORING IS APPROPRIATE
Product characteristics
Vapor monitoring must be used with products that
vaporize readily (e.g., gasoline)
-------
SLIDE V-50
WHEN VAPOR MONITORING IS APPROPRIATE
Soil conditions
Backfill around tank must allow the passage of
vapors
Soil must be clean and should not contain
substances that will produce vapors
-------
SLIDE V-51
THE EFFECT OF SOIL CONDITIONS ON
VAPOR CONCENTRATIONS AT A WELL
8000
6000 -
Q.
a.
c
&
15
£4000
o
O
-------
SLIDE V-52
WHEN VAPOR MONITORING IS APPROPRIATE
Climatic factors
Temperature affects the volatility of released product
-------
SLIDE V-53
WHEN VAPOR MONITORING IS APPROPRIATE
Geologic conditions
This method cannot be used in areas with high
ground water, which interferes with vapor detection
Water fills spaces between soil particles
-------
SLIDE V-54
CONSIDERATIONS
Can easily be integrated with tank vapor monitoring
system
-------
SLIDE V-55
HOW SIR WORKS
Daily measurements of product level in tank combined
with complete records of all withdrawals from the LIST
and deliveries to the UST
SIR vendor uses sophisticated statistical software to
conduct computerized analysis of data
SIR vendor provides monthly reports that can identify if
UST is leaking
SIR must be done monthly and meet the PD/PFA and
minimum detectable leak rate (0.2 gallons per hour)
Monthly SIR results must be available at the UST facility
-------
SLIDE V-56
WHEN SIR IS APPROPRIATE
UST system characteristics
Requires daily measurements
Product characteristics
Generally not restricted by product type
Soil conditions
No restrictions
Climatic factors
Temperature changes affect data, so SIR vendors must take climatic
factors into consideration
Geologic conditions
SIR for piping is not affected by geologic conditions
-------
SLIDE V-57
CONSIDERATIONS
SIR can be used for tank and piping
SIR is a very sophisticated statistical analysis that must
meet Federal requirements
SIR requires the use of good inventory measurement
practices
-------
SLIDE V-58
CONSIDERATIONS
Data can be sent to SIR vendor on paper or using computer
modems or diskettes
SIR can identify leaking systems, miscalibrated meters, tilted
tanks, and loss resulting from theft
SIR requires minimal investment of staff time and equipment
costs; overall costs compare favorably to other methods
State and local governments can place restrictions on SIR
use
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SLIDE V-59
WHAT DO I NEED TO KNOW ABOUT UST PIPING
MONITORING AND LEAK DETECTION?
UST Piping
Leak Detection for UST Piping
Leak Detection Methods
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