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
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            CHICAGO

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