United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-420) WF
500/B-92/001a
April 1992
&EPA Introduction to Leak
Detection
Understanding Federal
Release Detection
Requirements and Acceptable
Release Detection Methods
Student Manual
Printed on Recycled Paper
-------
Contents
Page
NOTES TO THE STUDENT 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 1
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
3age
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. LEAK DETECTION FOR UST PIPING
A. Deadlines
B. Requirements
C. Methods
D. Requirements for PD/PFA
E. Standard test procedures
III. AUTOMATIC LINE LEAK DETECTORS
A. Automatic flow restrictors
B. Automatic flow shutoff devices
V. LINE TIGHTNESS TESTS
A. Direct volumetric line tightness test
B. Indirect line tightness test
V. MONTHLY MONITORING METHODS
A. Secondary containment with interstitial monitoring
B. Ground-water monitoring
C. Vapor monitoring ..:
D. Statistical inventory reconciliation
Page
3
3
4
5
6
6
7
7
8
11
11
13
15
15
17
19
21
APPENDIX
I. GLOSSARY OF LEAK DETECTION TERMS 1-1
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NOTES TO THE STUDENT
Welcome to "Introduction to Leak Detection."
This course presents State and local LIST staff with a basic survey of Federal release detection
requirements and acceptable methods of release detection. The 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.
VII
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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
Student Notes
OVERVIEW OF LEAKING UNDERGROUND
STORAGE TANK SYSTEMS (USTs)
A. The problem
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.
Leaking tanks pose a threat to
ground water. Releases from
USTs into water supplies used for
drinking and other purposes can
endanger public health.
The threat of leaking tanks is not
limited to ground water. Other
considerations are:
Contamination of surface
waters;
Slide 1;
Slide 1A (photo):
Slide 2:
Slide 3 (graphic):
Slide 4:
Slide 5:
Chapter One, Page 1
-------
Lecture Notes
Student Notes
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:
Slide 7 (graphic):
Slide 8 (graphic):
Slide 9 (graphic):
Chapter One, Page 2
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Lecture Notes
Student Notes
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):
Slide 10:
Slide 11:
Slide 12:
Chapter One, Page 3
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Lecture Notes
Student Notes
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.
UST regulations require
preventing, detecting, and
cleaning up leaks and spills.
Chapter One, Page 4
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Lecture Notes
Student Notes
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:
Inventory control combined with tightness
testing;
Manual tank gauging;
Automatic tank gauging; and
Statistical inventory reconciliation.
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.
2.
3.
4.
B.
1.
2.
Vapor monitoring; and
Ground-water monitoring.
Slide 13:
Slide 14:
Slide 15:
Slide 16:
Chapter One, Page 5
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Lecture Notes
Student Notes
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:
Slide 18:
Chapter One, Page 6
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Lecture Notes
Student Notes
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:
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
Ubtitle 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 48 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
fests 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
P>lume1. 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
$43.75/ 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
(513) 569-7562
6/17/91 SPEC
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Audiovisual Programs
VIDEOS
AVAILABLE FROM
ptralght 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 UST
regulations [To\a\ 35 minutes].)
Part 1: Straight Talk From Tank Owners. (Owners address the problems of
UST 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, MD20814
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 UST Facility Compliance
Inspections"
(Covers major steps of UST inspections from protocols and equipment to
enforcement and followup; from cathodic protection to leak detection. Although
it is directed at inspectors, the video is also helpful to owners and operators
[30 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
-------
Audiovisual Programs
VIDEOS
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.)
Parti: Tanks (24 minutes)
Part 2: Piping (16 minutes)
Cost: $16.00 prepaid
Environmental Media Center
P.O. Box30212
Bethesda.MD 20814
OR CALL TOLL FREE:
1-800-522-0362
(301-229-1944 in Maryland)
Visa and MasterCard accepted
"Searching (or the Honest Tank: A Guide to UST Facility Compliance
Inspections"
(Covers major steps of UST inspections from protocols and equipment to
enforcement and followup; from cathodic protection to leak detection. Although
it is directed at inspectors, the video is also helpful to owners and operators
[30 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
S LI D ES 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
CNMI
Virgin \s.
PR Oa
CD °
EPA Regional UST Program Managers
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
£41 Chestnut Building
Wailcode: 3HW63
Philadelphia, PA 19107
215-597-7354
FTS 597-3177
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
AK UST/LUST CONTACT2
AK Dept. of Environmental Conservation
Contaminated Sites
410 Willoughby Avenue, Suite 105
Juneau, AK 99801-1795 907-465-5250
AL 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
AR UST/LUST CONTACT1
AR Dept. of Pollution Control & Ecology
Regulated Storage Tank Division
P.O. Box 8913, 72219-8913
8001 National Drive
Little Rock, AR 72219-8913
501-562-6533
AZ UST/LUST CONTACT2
AZ Department of Environmental Quality
3033 North Central Avenue
Phoenix, AZ 85004 602-257-6984
CA UST/LUST CONTACT
CA State Water Resources Control Board
Division of Clean Water Program
2014 T Street
(P.O. Box 944212, Zip: 94244-2120)
Sacramento, CA 95814
UST: 916-739-4436
LUST: 916-739-4317
CO UST CONTACT
CO State Oil Inspection Office
1001 East 62nd Avenue, Room A1
Denver, CO 80216 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
CT UST/LUST CONTACT2
CT Dept. of Environmental Protection
Underground Storage Tank Program
165 Capitol Avenue
Hartford, CT 06106 203-566-4630
DC 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
715 Grantham Lane
Newcastle, DE 19720 302-323-4588
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
DesMoines.lA 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.
State has 1 UST and 1 LUST Contact; both have the same address and telephone number.
3/92
-------
State UST/LUST Program Offices
MS UST/LUST CONTACT1
MS Department of Environmental Quality
Bureau of Pollution Control
Underground Storage Tank Section
P.O. Box 10385
Jackson, MS 39289-0385
601-961-5171
MT UST/LUST CONTACT1
MT DepL 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., Room 302
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
Groundwater Sect., Water Quality Division
301 Centennial Mall South, Box 98922
Lincoln, N E 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
123 W. Nye Lane
Carson City, NV 89710 702-687-5872
NY UST/LUST CONTACT1
NY DepL 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 DepL 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 DepL 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 DepL 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 DepL 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 DepL 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 206-459-6272
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
US TERRITORIES
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. 80x11488
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
has 1 person serving as both the UST and LUST Contact.
State has 1 UST and 1 LUST Contact; both have the same address and telephone number.
3/92
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SLIDE 1-3
DISTRIBUTION OF TANK TYPES AT
GASOLINE SERVICE STATIONS
Bare Steel
(84%)
PROTECTED
AGAINST
LEAKS
Cathodically Protected
PROTECTED
AGAINST
LEAKS
Fberglass-Reinforced
Plastic (11%)
Source: Kegulatory Impact Anatysis. August 24.1988.
-------
SLIDE 1-7
WHERE RELEASED PRODUCT TRAVELS
Gasoline
Vapors
Groundwater Flow
Water Supply
Well
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%)
Industry
(39%)
Farmers
(11%)
Gas Stations
(39%)
-------
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
Student Notes
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;
Slide 1:
Slide 2:
Slides 3 and 3A (graphic and photo):
Slide 4:
Chapter Two, Page 1
-------
Lecture Notes
Student Notes
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:
Chapter Two, Page 2
-------
Lecture Notes
Student Notes
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:
Slide 6A (photo):
Slide 6B (photo):
Slide 6C (photo):
Slide 6D (photo):
Chapter Two, Page 3
-------
Lecture Notes
Student Notes
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
1. A pumping system draws or
pushes product through the pro-
duct delivery lines to a delivery
hose, which dispenses the pro-
duct.
2. At retail stations, meters attached
to product dispensers measure
the volume of product dispensed
from the UST system.
5.
Slide 6E (photo):
Slide 6F (photo):
Slide 7:
Chapter Two, Page 4
-------
Lecture Notes
Student Notes
D. The site
1. Excavation zone is the entire area
that must be dug up in order to
install an UST.
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:
Slide 9 (graphic):
Slide 10 (Review/Wrap Up):
Chapter Two, Page 5
-------
SLIDE 11-3
TYPICAL RETAIL GASOLINE STATION
Tank Truck
Delivery Hose
Submerged Pump
Assembly
Vent Pipes
Line Leak
Detector
Submerged Pump
Assembly
Product Dispensers
Product Delivery Line
-------
SLIDE 11-9
SCHEMATIC OF A SUBSURFACE
ENVIRONMENT
( TANK )
^Excavation
Zone
Released
Product
Dry
Soil
Capillary Zone
t
Water Table
Aquifer
/^>5^!24S«2iS»2i»?%i!3%KS^
Impermeable Boundary
-------
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
Student Notes
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:
Slide 2:
Chapter Three, Page 1
-------
Lecture Notes
Student Notes
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:
Slide 4:
Slide 5 (graphic):
Slide 6:
Slide 7:
Chapter Three, Page 2
-------
Lecture Notes
Student Notes
D. UST system size
1. Number of tanks
Slide 8:
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:
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
Student Notes
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 UST 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 UST regula-
tions because they are
under different regulations.
(See 40 CFR Parts 260-270
for hazardous waste regula-
tions.)
Slide 10:
Chapter Three, Page 4
-------
Lecture Notes
Student Notes
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:
Slide 12:
Slide 13:
Slide 14:
Chapter Three, Page 5
-------
Lecture Notes
Student Notes
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:
Slide 16:
Slide 17:
Chapter Three, Page 6
-------
Lecture Notes
Student Notes
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
Student Notes
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:
Slide 19:
Slide 20 (graphic):
Slide 21:
Chapter Three, Page 8
-------
Lecture Notes
Student Notes
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:
Chapter Three, Page 9
-------
Lecture Notes
Student Notes
IV. CLIMATIC FACTORS
A. Temperature
Slide 23:
1. Extreme temperatures or dramatic
changes in temperature may
affect the accuracy of certain leak
detection methods, and may
render other methods ineffective.
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
Student Notes
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 'hole1 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:
Slide 25:
Slide 26 (graphic):
Slide 27:
Slide 28:
Chapter Three, Page 11
-------
SLIDE 111-20
THE EFFECT OF SOIL CONDITIONS ON
VAPOR CONCENTRATIONS AT A WELL
8000
6000 -
.§
i
4000 -
2000 -
Dry gravel backfill
Dry sllty sand
Moist sand backfill
Wgt sand or clay
10 20
Number of Days
30
I
-------
SLIDE 111-26
THE EFFECT OF GROUND WATER ON THE
RATE AND FLOW THROUGH A HOLE
IN AN UST
Water table abovt level of
leak. Ground water enters
tank through hole.
Water
Table
Water table below level at tank.
Product escapes from hole.
Water Table
-------
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
Student Notes
GENERAL LEAK DETECTION
REQUIREMENTS
A. Deadlines
1. New tanks
Slide 1:
Slide 2:
Tanks installed after Decem-
ber 23, 1988, must comply
with UST leak detection
requirements when
Installed.
Slide 2A (graphic photo):
Slide 3:
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 Comply
By
Slide 4:
Before 1965
1965-1969
1970 -1974
1975-1979
1980-1988
December 1989
December 1990
December 1991
December 1992
December 1993
Or if installation date is unknown.
Chapter Four, Page 1
-------
Lecture Notes
Student Notes
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 (PD/
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 December 1990, 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:
Slide 7:
Chapter Four, Page 2
-------
Lecture Notes
Student Notes
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
Student Notes
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:
Slide 9:
Slide 9A (graphic photo):
Slide 10:
Slide 10A (graphic photo):
Slide 11 (graphic):
Slide 11A (photo).
Slide 11B (photo):
llde 11C (photo):
Chapter Four, Page 4
-------
Lecture Notes
Student Notes
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:
Slide 13 (graphic):
Slide 14:
Chapter Four, Page 5
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Lecture Notes
Student Notes
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:
Slide 16:
Slides 17 and 18:
Chapter Four, Page 6
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Lecture Notes
Student Notes
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.
Slide 19 (graphic):
Slide 20 (graphic):
Slide 20A (graphic photo):
Chapter Four, Page 7
-------
Lecture Notes
Student Notes
B.
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.
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.
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Slide 23:
Chapter Four, Page 8
-------
Lecture Notes
Student Notes
h.
With MTG, weekly measure-
ments of product levels are
taken with a gauge stick
inserted in the tank through
the fill pipe.
A test is conducted once
each week and lasts at least
36 hours.
The UST must not be in use
between measurements (no
product can be added or
withdrawn during this test
period).
Four measurements must be
taken:
Two at beginning of the
weekly test; and
Two at end of the weekly
test.
A calibration chart specific
to the tank is used to con-
vert product level measure-
ment into product volume.
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.
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):
Slide 24:
Slide 25 (graphic):
Slide 26:
Slide 27:
Chapter Four, Page 9
-------
Lecture Notes
Student Notes
Tank
Capacity
Weekly Monthly Test
Change Change Duration
(gal) (gal.) (hrs.)
Up to 550 10 5 36
551-1,000(64tx730 9 4 44
1,000(48
-------
Lecture Notes
Student Notes
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.
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Slide 31:
Chapter Four, Page 11
-------
Lecture Notes
Student Notes
3. Considerations
« - UST system must be
removed from service at
least 36 hours every week.
Equipment costs are very
low.
C. 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:
Slide 32A (graphic photo):
Slide 33:
Slide 34 (graphic):
Slide 35 (graphic):
Slide 36 (graphic):
Slide 36A (photo):
Slide 36B (photo):
Slide 36C (photo):
Slide 36D (photo):
Slide 36E (photo):
Slide 36F (photo):
Slide 36G (photo):
Chapter Four, Page 12
-------
Lecture Notes
Student Notes
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:
Slide 38 (graphic):
Chapter Four, Page 13
-------
Lecture Notes
Student Notes
Vapor monitoring checks for
presence of product fumes
in the interstitial space.
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:
Slide 40:
Chapter Four, Page 14
-------
Lecture Notes
Student Notes
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:
Slides 42, 43, and 44:
Chapter Four, Page 15
-------
Lecture Notes
Student Notes
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):
Slide 45:
Slide 46 (graphic):
Slide 47 (graphic):
Slide 48 (graphic):
Chapter Four, Page 16
-------
Lecture Notes
Student Notes
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:
Slide 50:
.
Slide 50A (photo):
Slide SOB (photo):
Slide 50C (photo):
Slide 51:
Slide 52 (graphic):
Slide 53 (graphic):
Chapter Four, Page 17
-------
Lecture Notes
Student Notes
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
tower than that of water.
(Product must float on top of
water.)
Slide 54 (graphic):
Slide 55:
Slide 56:
Chapter Four, Page 18
-------
Lecture Notes
Student Notes
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 UST 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.
Slide 57:
Slide 57A (photo):
Slide 57B (photo):
Slide 57C (photo):
Slide 58:
Slide 59:
Chapter Four, Page 19
-------
Lecture Notes
Student Notes
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 wel
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.
Slide 60 (graphic):
Slide 61:
Chapter Four, Page 20
-------
Lecture Notes
Student Notes
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 LIST 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.
Slide 62:
Slide 63 (graphic):
Slide 64 (graphic):
Slide 65 (graphic):
Chapter Four, Page 21
-------
Lecture Notes
Student Notes
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):
Slide 65B (graphic photo):
Slide 66:
Slide 66A (graphic photo):
Slide 66B (graphic photo):
Slide 66C (graphic photo):
Slide 67:
Slide 68:
Slide 69 (graphic):
Slide 70:
Chapter Four, Page 22
-------
Lecture Notes
Student Notes
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 UST.
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 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.
Slide 73A:
Chapter Four, Page23A
-------
Lecture Notes
Student Notes
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
requirements can be more restrictive.
2. When SIR is appropriate
a. LIST 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:
Slide 73C:
Slide 73D:
Chapter Four, Page 238
-------
Lecture Notes
Student Notes
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 LIST operator must
check for water at least once a month.
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:
Slide 73F:
Chapter Four, Page 23C
-------
Lecture Notes
Student Notes
SIR requires minimal investment of staff time
and equipment costs (usually involving a
gauge stick and pastes that help identity
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, Page 23D
-------
Lecture Notes
Student Notes
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 dairy
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:
Slide 74A (graphic photo):
Slide 75:
Chapter Four, Page 24
-------
Lecture Notes
Student Notes
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:
Slide 76A (photo):
Slide 77:
Slide 78 (graphic):
Slide 79 (graphic):
Chapter Four, Page 25
-------
Lecture Notes
Student Notes
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 tang 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:
Slide 81:
Slide 82 (graphic):
Slide 83:
Slide 83A (photo):
Chapter Four, Page 26
-------
Lecture Notes
Student Notes
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 newty-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:
Slide 85:
Slide 86:
Chapter Four, Page 27
-------
Lecture Notes
Student Notes
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.
Slide 87:
Slide 88:
Chapter Four, Page 28
-------
Lecture Notes
Student Notes
a 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:
Slide 90:
Slide 91:
Slide 92:
Slide 93 (graphic):
Slide 93A (graphic photo):
Slide 93B (photo):
Slide 93C (photo):
Slide 930 (photo):
Chapter Four, Page 29
-------
Lecture Notes
Student Notes
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):
Slide 93F (photo):
Slide 94 (graphic):
Slide 95 (graphic):
Slide 96:
Chapter Four, Page 30
-------
Lecture Notes
Student Notes
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):
Slides 97 and 98 (graphics):
Chapter Four, Page 31
-------
Lecture Notes
Student Notes
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.
Slide 99:
Chapter Four, Page 32
-------
Lecture Notes
Student Notes
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.
tf water table is higher than
location of hole in leaking
tank, ground water exerts
pressure on hole.
Slide 100:
Chapter Four, Page 33
-------
Lecture Notes
Student Note*
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:
Slide 102:
Chapter Four, Page 34
-------
Lecture Notes
Student Notes
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. UST 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:
Slide 40:
Chapter Five, Page 17
-------
Lecture Notes
Student Notes
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:
Slide 42:
Slide 43:
Slide 44:
Chapter Five, Page 18
-------
Lecture Notes
Student Notes
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 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.
May be retrofitted. When
retrofitting, installer must be
cautious not to puncture
piping.
Slide 45 (graphic):
Slide 46:
Slide 47:
Slide 48:
Chapter Five, Page 19
-------
Lecture Note*
Student Notes
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:
Slide 50:
Slide 51 (graphic):
Slide 52:
Slide 53:
Chapter Five, Page 20
-------
Lecture Notes
Student Notes
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 UST and of
deliveries to the UST.
Slide 54:
Slide 55:
Chapter Five, Page 21
-------
Lecture Notes
Student Notes
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 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.
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 LIST
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:
Chapter Five, Page 22
-------
Lecture Notes
Student Notes
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:
Slide 58:
Chapter Five, Page 23
-------
Lecture Notes
Student Notes
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:
Chapter Five, Page 24
-------
SLIDE V-5
AMERICAN AND EUROPEAN PIPING SYSTEMS WITH
CHECK VALVES
American System
European System
Check Valve
-------
SLIDE V-10
PRESSURIZED PIPING SYSTEM
Gas Pump G"PumP
Line Leak
Delect of
FVJ'VWWYSK-:?'V'.' ''
r.'...*«.-/'S.'.'il-.i i »:«i-"-'-J'i
^£^«=$
^^S^'-f'-'f.'
-------
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.
Restrlctors - 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
-------
SLIDE IV-11
SCHEMATIC OF AN AUTOMATIC TANK GAUGING SYSTEM
REMOTE ATG MONITOR
PUMP OR PUMP
CONTROL CONSOLE
FILL PIPE
Probe (Level, Temperature,
and Water Sensor)
(OPTIONAL WIRING)!
-------
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 chad
- Test times
Alarm levels
TESTING
OR
INVENTORY
Shutdown tank operations
- Temperature to reach
equilibrium
- Tank deformation to subside
Make temperature
and level
measurements
/ X
TESTING
Reconcile
inventory data
Analyze
test data
A
N
A
L
Y
S
I
S
-------
SLIDE IV-19
o>
o
o
o
O)
c
00
O
2
3
5
0)
0.
o
OVER TIME OF TOPPING THE TANK WITH
COLDER PRODUCT
0.50
O 0.40 -
0.30 -
0.20 -
0.10
0.00
214
11
Tlme-h
-------
SLIDE IV-25
SAMPLE CALIBRATION CHART CONVERTING
PRODUCT DEPTH TO GALLONS*
^\Tank Size
Deptn\^^
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.
491/2"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
* Note that product depth in left column converts to gallons in the other
columns.
-------
SLIDE IV-34
TANKS IN A CONCRETE VAULT
CONCRETE OR
ASPHALT SURFACE
MAYOR
MAY NOT -i
BE
BACKFILLED
CONCRETE
INTERIOR
LINING
SUMP
SINGLE WALL TANK
-------
SLIDE IV-35
TWO DOUBLE-WALLED TANK
CONFIGURATIONS
y^. /7\
Sampling
Standpipe
or
Electronic
Detection
Double-Walled Steel Tank
Interstitial Space
Ooubie-Wifled FRP Tank
-------
SLIDE IV-36
TANK WITH EXCAVATION LINER
Monitoring Point Suitable
for Leak Detection and
Withdrawal of Accumulated
Water
Pavement
Trench Top Liner
Tank
Excavation
Liner
Some
Partially
Enclosed Liners
Would End Here
Pipe Leak
Detection
Monitoring
Point
Collar to Connect
Pipe Trench to
Tank Liner
Trench Liner
Interstitial Space
Slotted Pipe for
Leak Detection and
Withdrawal of Water
Native Soil
-------
SLIDE IV-38
DOUBLE-WALLED TANK SHOWING PLACEMENT OF
BOTH VAPOR AND LIQUID SENSORS
Liquid Sensor
-------
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
CASINO
ANNULAR SEAL
FILTER PACK
-------
SLIDE IV-47
MONITORING WELL IN EXCAVATION ZONE
Monitoring Well
Pavement
!^^^^^:^l*^?>?y^y.%?^^
^?^^^^^f^^^^^^^^^^^^lf^^^
%£..^t^«Xtr^'Xv.T^%iN3^>.£>r~^>:.ni^^
-->;i«&,4t.-M. ^-r. -.r>. i>.3?>^*>''t»"r^i*<'.;'w;"a>>'r *i'*.i'.rai*'?*.i;W.'f *' >*.a-J'*?*?*>Ji'd«atti
Free Product Layer
Product/Water Contact
Water Table
Surface
Well Screen
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 RANCH .
I
I
Mil PRODUCT |
'/////////////*
n
GROUND SURFACE
High Water Table
MAMOIOP WATER TAIL!
FLUCTUATION
Low Water Table
-------
SLIDE IV-52
SCHEMATIC OF A DIFFERENTIAL
FLOAT DEVICE
Monitor
Reinforced Concrete Slab
Over Tank
X
Top Alignment Spacer
Monitoring Wtfl
-Bottom Alignment Spacer
Product Float
Probe
Water Float
Bottom Locking Nut
-------
SLIDE IV-53
SCHEMATIC OF A MECHANICALLY
ACTIVATED PRODUCT
SOLUBLE DEVICE
Ground Surface
% Retrieval
//Groondwaterz
liable
Spring Loaded Indicator
-------
SLIDE IV-54
SCHEMATIC OF THERMAL
CONDUCTIVITY DEVICE
Monitoring Wdl -*.
-------
SLIDE IV-60
POORLY PLACED GROUND-WATER
MONITORING WELL
Product-Filtod
Fractures
Nott: No Frw Product in W«ll
Fractured Rock
Karstic Limestone
-------
SLIDE IV-64
UNDERGROUND STORAGE TANK SYSTEM WITH
VAPOR MONITORING WELLS
VAPOR
MONITORING
WELL
VAPOR
MONITOR INQ
DEVICE
I
BACKFILL
NATIVE SOft.
-------
SLIDE IV-65
MAP VIEW OF TYPICAL UST SITE
WITH VAPOR MONITORING
VAPOR WELL IN
PRODUCT UNE BACKFILL
PRODUCT LINES
BACKGROUND VAPOR WELL
VAPOR WELL
MTANKIACXnU.
-------
SLIDE IV-69
THE EFFECT OF SOIL ON VAPOR
CONCENTRATIONS AT A WELL
8000
6000 -
I
UOOO -
I
2000 -
Dry gravel backfill
Dry sltty sand
Moist sand backfill
Wei sand or clay
10 20
Number of Days
-------
SLIDE IV-78
SAMPLE CALIBRATION CHART CONVERTING PRODUCT
DEPTH TO GALLONS*
^-vTank 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.
49V2"x 10'
4
13
24
38
52
68
86
104
124
144
165
187
209
232
255
1000 Gal.
64" x &
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 18*
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 gallons 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-82
GENERAL PROCEDURE FOR
INVENTORY CONTROL
Testing
Tank Gauging
Product gauge
Water gauge
Calibration
Volume of product determined
from calibration chart
Tank Stock Control
Withdrawals
Receipts
Recording & Reconciliation
Analysis
Interpretation
Leak
No Leak
-------
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-97
HOW TEMPERATURE CHANGES CAN
MISTAKEN FOR A LEAK
CAP
CONCRETE
CAP
CONCRETE
PRODUCT LEVEL
FILL TUBE PRODUCT LEVEL
NEW, COOLER 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
1
FILL TUBE
PRODUCT LEVEL
PRODUCT
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.
-------
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
Student Notes
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:
Slide 2:
Slide 2A (photo):
Slide 3:
Slide 4:
Slide 4A (photo):
Slide 4B (photo):
Chapter Five, Page 1
-------
Lecture Notes
Student Notes
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 'European1 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 'American1 system,
the check vah/e is located at
the top of the tank (angle
check) or at the bottom of
the suction line (foot vatve).
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.
Slide 4C (graphic photo):
Slide 5 (graphic):
Chapter Five, Page 2
-------
Lecture Notes
Student Notes
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 'American1 suction
piping types need to meet
the following deadlines.
4 - 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:
Slide 7:
Slide 8:
Chapter Five, Page 3
-------
Lecture Notes
Student Note*
installation Must Comply
Data By
Before 1965
1965-1968
1970-1974
1976-1979
1980-1988
December 1989
December 1990
December 1991
December 1992
December 1993
Or tf installation date is unknown.
B. Requirements
1. Pressurized piping (new and
existing)
Each pressurized piping run
must have an automatic line
teak detector OLD).
Pressurized piping must also
have one of the following:
Monthly ground-water
monitoring; or
Monthly vapor monitor-
ing; or
Monthly Interstitial mon-
itoring; Of monthly SIR;
Annual tightness test
2. Suction piping
No leak detection is required
i 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:
Slide 10 (graphic):
Slide 11:
Slide 12:
Chapter Five, Page 4
-------
Lecture Notes
Student Notes
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:
Slide 14:
Chapter Five, Page 5
-------
Lecture Notes
Student Notes
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:
Chapter Five, Page 6
-------
Lecture Notes
Student Notes
AUTOMATIC UNE LEAK DETECTORS
A. Automatic flow restrlctora
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:
Slide 17:
Slide 18:
Slide 18A (photo):
Chapter Five, Page 7
-------
Lecture Notes
Student Notes
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:
Slide 20:
Chapter Five, Page 8
-------
Lecture Notes
Student Notes
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:
Slide 22:
Chapter Five, Page 9
-------
Lecture Notes
Student Notes
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:
Slide 24:
Chapter Five, Page 10
-------
Lecture Notes
Student Notes
IV. UNE 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/h at 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:
Slide 26:
Slide 26A (photo):
Slide 26B (photo):
Slide 26C (photo):
Chapter Five, Page 11
-------
Lecture Notes
Student Notes
A pressure gauge on
the hand pump, or
temporality 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.
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.
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 vatves, etc. .
Slide 27:
Slide 28:
Chapter Five, Page 12
-------
Lecture Note*
Student Notes
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:
Slide 30:
Chapter Five, Page 13
-------
Lecture Notes
Student Note*
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
fittings 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:
Chapter Five, Page 14
-------
Lecture Notes
Student Notes
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:
Slide 33:
Slide 34:
Slide 35:
Chapter Five, Page 15
-------
Lecture Notes
Student Notes
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.
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:
Slide 37:
Slide 38:
Chapter Five, Page 16
------- |