United States
Environmental Protection
Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S2-86/001 July 1986
v>EPA Project Summary
Underground Tank Leak
Detection Methods:
A State-of-the-Art Review
Shahzad Niaki and John A. Broscious
The full report is a state-of-the-art
review of available and developing
methods for finding small leaks in
underground storage tanks used pri-
marily for gasoline and other liquid
petroleum fuels. It describes (based on
information provided by the manu-
facturers or practitioners) a total of
36 volumetric, nonvolumetric, inven-
tory monitoring, and leak effects mon-
itoring detection methods; provides
general engineering comments on each
volumetric and nonvolumetric leak de-
tection method; and discusses vari-
ables which may affect the accuracy
of detection methods. The emphasis
throughout is on volumetric and non-
volumetric leak detection methods.
This Project Summary was devel-
oped by EPA's Hazardous Waste Engi-
neering Research Laboratory, Cincin-
nati, OH, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
Statement of the Problem
In recent years, the increase in leaks
from underground gasoline storage tanks
has had a significant adverse environ-
mental impact on the United States. Cur-
rent estimates from governmental and
industrial sources are that between 1.5
to 3.5 million underground storage tanks
exist in the nation. Estimates of the num-
ber of leaking tanks range from 75,000
to 100,000; and 350,000 others may
develop leaks within the next five years.
(Conference Report on H.R. 2867 Haz-
ardous and Solid Waste Amendments of
1984, Congressional Record-House,
H11140, October 3, 1984.) The 1983
National Petroleum News Factbook Issue
forecasts the existence of approximately
140,000 gasoline service stations in the
United States at the end of 1983. New
York State estimates that 19 percent of
its 83,000 active underground gasoline
tanks are now leaking. Maine estimates
that 25 percent of its 1,600 retail gaso-
line underground tanks are leaking
approximately 11 million gallons yearly.
In Michigan 39 percent of groundwater
contamination incidents are attributed to
storage tanks.
One of the primary causes of tank
leakage is corrosion of the storage tanks.
Product loss from leaking tanks may
cause an adverse effect on the environ-
ment, endanger lives, reduce income,
and require the expenditure of millions
of dollars for cleanup. To prevent or
reduce the adverse effects of gasoline
leakage, an accurate method must be
used to determine whether or not an
underground tank is leaking.
The 1984 Resource Conservation and
Recovery Act (RCRA) amendments regu-
late underground storage tanks contain-
ing petroleum products and substances
defined in Comprehensive Environ-
mental Response, Compensation, and
Liability Act (CERCLA). RCRA regulations
specify release detection, prevention,
and corrections and require a leak detec-
tion system, an inventory control system,
and a tank testing (or equivalent) system.
States are also passing legislation and
writing regulations requiring both staged
replacement of existing underground
tanks and installation of monitoring wells
to detect leaks. Performance standards
for new tanks will be specified under
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RCRA and included in various state
regulations.
Objective
The objective of the full report is to
identify existing and developing tech-
niques to detect leaks in underground
fuel storage tanks. This objective is ac-
complished by a review of the manu-
facturer's description of each method,
its capabilities, and its,claimed precision
and accuracy.
The variables affecting leak detection
methods are introduced in Section 5 of
the report. This information should give
the reader an understanding of the major
variables and their effects on the ac-
curacy of various leak detection methods.
Section 6 presents a description of each
detection method based on the available
literature from the manufacturer or
practitioner. The descriptions in Section
6 of the manufacturer's techniques for
offsetting the effects on each detection
method of these major variables are
based on information from the manu-
facturer's literature, reports, and/or
verbal communications between the
authors and the staff of the manufac-
turer. This information was reviewed for
correctness by most of the manufac-
turers, practitioners, or developers of
the detection methods (instruments).
Independent engineering evaluations of
error sources for each detection method
are provided by the authors. Finally,
Tables 1 through 9 in Section 2 sum-
marize the capabilities of the leak detec-
tion methods. Information in these tables
is primarily from each manufacturer's
description and, where noted, from the
engineering comments in Section 6.
Table 1 provides the phone number and
contact name of the manufacturer/
practitioner for each manufactured leak
detection method.
Summary
Existing and developing leakdetection
methods were reviewed, and techniques
for offsetting the effects of variables
which affect accuracy were evaluated. In
Tables 1 through 9 of the report, general
information, general operational capabil-
ities, and compensation for effects of
variables discussed in this text are sum-
marized for volumetric, nonvolumetric
and other leak detection methods for
underground storage tanks. Wherever it
is appropriate, in these summary tables,
the information furnished is based on
engineering comments and not on the
manufacturer's claim.
Table 1. Leak Detection Methods.
Leak Detection Testing Methods
Manufacture or Practitioner Phone Numbers
Phone Number Contact Name
Volumetric (Quantitative) Leak
Testing Methods
1. Ainlay Tank Tegrity Testing
(TTT)
2. AftCO HTC Underground Tank
Leak Detector
3. Certi-Tec Testing
4. "Ethyf Tank Sentry Testing
5. EZY-CHEK Leak Detector
6. Fluid-Static (Standpipe)
Testing
7. Health Petro Tite Tank and
Line Testing (Kent-Moore
Testing)
8. Helium Differential Pressure
Testing
9. Leak Lokator Test (Hunter
Sunmark Leak Detection)
10. Mooney Tank Test Detector
11. "PACE Tank Tester
12. *PALD-2 Leak Detector
13. Pneumatic Testing
14. Tank Auditor
15. *Two-Tube Laser
Interferometer System
Nonvolumetric (Qualitative) Leak
Testing Methods
1. 'Acoustical Monitoring
System (AMS)
2. Leybold-Heraeus Helium
Detector, Ultratest M2
3. Smith & Denison Helium Test
4. TRC Rapid Leak Detector for
Underground Tanks and Pipes
5. 'Ultrasonic Leak Detector.
Ultrasound
6. VacuTect (Tanknology)
7. Varian Leak Detector
Inventory Monitoring
1. Gage Stick
2. MFP-414 Leak Detector
(312) 328-6119 Mr. John Ainlay
(312)333-3000 Mr. Gary L Everett
(612)487-1484
(609) 452-8600
(517)684-7180
Mr. Jonathan Nedved
Mr. A.V. Morschauser
Mr. John Homer
Method is used by different contractors
(617)344-1400
(415)228-8400
(215)296-7380
(504)241-0453
(416)443-7032
(Not Available)
3425 W. 30th Ave.
Vancouver, B.C.,
V6S1W3 CANADA
Mr. Jack Stillwagon
Mr. John Schweizer
Mrs. Donna Hymes
Mr. Joseph Mooney
Mr. Jack Witherspoon
Mr. Werner Grundmann
Method is used by different contractors
(617) 740-1717 Mr. William E. Baird
(415) 424-1251 Mr. Joseph W. Maresca
(615)966-4773
(412)327-5700
(415) 782-9788
(602) 623-0200
(914)592-1220
(403) 483-3506
(617)935-5185
Mr. Charles B. Oh
Mr. Wm. C. Worthington
Mr. Wm. H. Burkhart
Mr. Glenn Thompson
Mr. Mark A. Goodman
Mr. Edward Adams
Mr. Roger Schneider
Method is used by different contractors
(617) 238-6911 Mr. Stanley Hayes
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Table 1. (continued)
Leak Detection Testing Methods
3. TLS-150 Tank Level Sensor
fVeeder-Root)
Leak Effects Monitoring
1. Collection Sumps
2. Dye Method
3. Ground Water or Soil Core
Sampling
4. Interstitial Monitoring in
Double-Walled Tanks
5. LA.S.P. Monitoring System
6. Observation Wells
7. Pollulert and Leak-X
Detection Systems
8. Remote Infrared Sensing
9. Surface Geophysical Methods
10. U-Tubes
11. Vapor Wells
Phone Number
Contact Name
(203) 527-7201
Mr. Tony Spera
Method is used by different contractors
Method is used by different contractors
Method is used by different contractors
Method is used by different contractors
(214)271-2561
Industrial System
Marketing
Method is used by different contractors
(317)261-1130
(212)822-6767
Mrs. Joyce Rizzo (Pollulert)
Mr. John Gelles (Leak-X)
Method is used by different contractors
Method is used by different contractors
Method is used by different contractors
Method is used by different contractors
Recommendations
The accuracy and precision of volu-
metric leak detection methods (at least)
should be determined in order to permit
selection of the ones appropriate to any
specific need. A cost-effective procedure
is to make use of signal/noise theory and
a high quality data base to estimate the
likely performance of each method under
a variety of representative conditions,
and to verify performance by evaluating
the method under a few selected, con-
trolled conditions in a full-scale test
apparatus.
To conduct this survey, the American
Petroleum Institute (API), and the Petro-
leum Equipment Institute (PEI) were con-
tacted for assistance in developing a
comprehensive list of available detection
methods. A limited patent search was
performed to identify methods currently
being developed, but not yet available
commercially. In all, fifteen volumetric
leak testing, seven non-volumetric leak
testing, three inventory monitoring, and
eleven leak effects monitoring methods
were found.
The information in the report is based
almost entirely on information provided
by the manufacturers and practitioners
of the detection methods.
Conclusions
The conclusions listed below are
based on the review of leak detection
methods described in this report.
1. Variables affect the testing results
of available or developing volu-
metric, nonvolumetric, and in-tank
monitoring methods used for leak
detection of underground tank sys-
tems. These variables are potential
sources of errors in using the de-
tection methods successfully. The
importance of each variable may
vary due to the characteristics of
the tank being tested and to such
test conditions as the temperature
of additional product used to fill a
tank prior to testing, depth of the
water table, tank deformation,
random variation of ambient tem-
perature or pressure, tank inclina-
tion, product vapor pressure, and
tank age.
2. The 36 methods identified include
15 volumetric leak detection, 7
nonvolumetric leak detection, 3 in-
tank monitoring, and 11 leak ef-
fects monitoring methods.
3. Detection methods attempt to com-
pensate for variables affecting
accuracy in various ways.
4. Available data on the performance
evaluation of the leak detection
methods reviewed were not ade-
quate to determine their relative
accuracy.
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Shahzad Niaki and John A. Broscious are with IT Corporation. Pittsburgh, PA
15235.
John S. Far low is the EPA Project Officer (see below).
The complete report, entitled "Underground Tank Leak Detection Methods: A
State-of-the-Art Review,"(OrderNo. PS 86-737155/AS; Cost: $16.95, subject
to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, V'A 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Releases Control Branch
Hazardous Waste Engineering Research Laboratory—Cincinnati
U.S. Environmental Protection Agency
Edison. NJ 08837
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-86/001
U
1329 PS
ENV.RPROTECTIOH ACENCV
CHICAGO
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