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EPA/600/4-87/016
May 1988
SURVEY OF VENDORS OF EXTERNAL
PETROLEUM LEAK MONITORING DEVICES
FOR USE WITH UNDERGROUND STORAGE TANKS
by
B. Eklund
and
W. Crow
Radian Corporation
Austin, Texas 78766
Contract No. 68-02-3994
Project Officer
J. Jeffrey van Ee
U.S. Environmental Protection Agency
Environmental Monitoring Systems Laboratory
Las Vegas, Nevada 89114
ENVIRONMENTAL MONITORING SYSTEMS LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
LAS VEGAS, NEVADA 89114
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Contents
Section Page
Executive Summary v
1 Introduction 1-1
1.1 Background • 1-1
1.2 Program Objectives 1-2
1.3 Scope of Work and Report Outline 1-2
1.4 Overview of Leak Detection and Tank System Design 1-2
1.4.1 Leak Detection 1-2
1.4.2 Tank System Design 1-3
2 Conclusions and Summary of Results
2.1 Conclusions 2-1
2.2 Summary of Results 2-1
2.2.1 Summary of General Findings for Monitoring Systems . . . 2-1
2.2.2 Summary of Findings for Intermittent Liquid-Phase Detectors 2-1
2.2.3 Summary of Findings for Continuous Liquid-Phase Detectors . . 2-1
2.2.4 Summary of Findings for Intermittent Gas-Phase Detectors 2-2
2.2.5 Summary of Findings for Continuous Gas-Phase Detectors 2-2
3 Technical Approach
3.1 Literature Search 3-1
3.2 Vendor List 3-1
3.3 Vendor Survey 3-1
4 Results
4.1 Discussion of Survey 4-1
4.2 Tabulated Results From Survey 4-1
4.2.1 Principle of Operation 4-1
4.2.2 Other Results 4-12
4.3 Evaluation of Results 4-12
4.3.1 Performance Categories of Leak Monitoring Techniques 4-12
4.3.2 Site-Specific Factors 4-23
4.4 Discussion of Results 4-23
4.4.1 Overall Results 4-23
4.4.2 Questionnaire Results 4-26
5 References 5-1
6 Bibliography
6.1 Selected Bibliography 6-1
6.2 Additional Citations Identified in Literature Search 6-2
Appendix A - List of Vendors ' A-1
Appendix B - Questionnaire Format B-1
Appendix C - Tabulated Survey Results . . C-1
G Glossary of Terms G-1
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Tables
Number Page
1 Characteristics of Leak Detection Sensors vii
4-1 List of Vendors and Response to Survey 4-2
4-2 Commercially Available Leak Monitoring Techniques 4-5
4-3 Detection Specificities of Various Leak Monitoring Techniques 4-14
4-4 Detection Capabilities of Various Leak Monitoring Techniques 4-15
4-5 Experience of Various Leak Monitoring Techniques 4-17
4-6 Costs for Various Leak Monitoring Techniques 4-19
4-7 Recommended Procedures for Various Leak Monitoring Techniques 4-20
4-8 Effect of Site-Specific Factors and Design Options on Selection of Leak Detection Methods . . 4-24
4-9 Relative Advantages/Disadvantages of Leak Monitoring Techniques 4-25
4-10 Summary of Available Test Procedures and Results for Leak Monitors 4-27
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Figures
Number Page
1-1 Elements of an Underground Storage Tank Installation 1-4
1-2 Example of Observation Well Installation 1-5
1-3 Example of Vapor Monitoring Well 1-6
4-1 Bailer Used for Grab Sampling 4.5
4-2 Schematic of a Radiation infrared (IR) Detector 4-6
4-3 Schematic of a Photoionization Detector (PID) 4-6
4-4 Schematic of Leak Monitoring System Using Product-Soluble Pressurized Tube 4-7
4-5 Schematic of Mechanically Activated, Product-Soluble Device 4-9
4-6 Schematic of Electrically Activated, Product-Soluble Device 4-10
4-7 Schematic of Electrical Resistivity Sensor Coated With Product-Soluble Polymer 4-11
4-8 Schematic of Typical Installations of Thermal Conductivity Sensor 4-12
4-9 Schematic of Product-Permeable Device 4-13
4-10 Decision Tree for Detector Classification 4-23
IV
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Executive Summary
Underground storage tanks (USTs) and their
associated piping are major potential sources of
environmental contamination. Since the 1984
Amendments to the Resource Conservation and
Recovery Act (RCRA) require regulation of
underground storage tank systems, the U.S.
Environmental Protection Agency (EPA) is currently
investigating topics related to USTs to aid in
developing regulations. EPA has contracted with the
Radian Corporation to compile information on the
various types of external (out-of-tank) monitoring
systems or techniques which can be used to detect
leaks or spills of petroleum hydrocarbon products. The
compiled data were used to categorize external
petroleum leak monitoring devices or techniques by
function and type, and the data will aid in the future
development of performance criteria for commercially
available external leak monitoring methods. The
present study was conducted in 1986 and is limited to
external (outside-the-tank) petroleum leak monitoring
devices. It supports the EPA effort by providing
information on the number, type, and performance
capabilities of available leak monitors.
The literature was searched to collect general
information on external petroleum leak monitors and,
more specifically, to develop a list of vendors.
Additional information was collected from equipment
vendors, trade groups, and other researchers. A
questionnaire soliciting information on leak monitoring
devices was developed and sent to the identified
vendors. The questionnaire covered six topics:
principle of operation, detection specificity, detection
capability, experience, cost, and recommended
procedures. The vendor list included vendors of UST
monitoring systems and detectors that could
potentially be used for the detection of petroleum
hydrocarbon leaks or spills. It should be noted that
this survey does not necessarily represent a complete
list of vendors that manufacture external monitors for
detecting petroleum leaks or spills from underground
storage tanks and piping. Some vendors were likely
to have been inadvertently omitted, and devices that
are currently being marketed could have changed
since this survey was performed. However, these
data will be useful in identifying the different
categories of commercial leak monitoring devices and
aiding in the development of performance criteria for
each monitoring category. This report summarizes
and tabulates vendor responses to the questionnaire.
The report also includes a discussion of related issues
that remain to be resolved before final performance
criteria can be established.
The data collection approach used in this study has
limitations. Reliance on vendor-supplied data was
necessary because of a lack of published, objective
evaluative test results. However, since these vendor
data have not been independently verified, it is
possible that some of these data are erroneous,
biased, or self-serving.
The literature search yielded relatively little useful
information on external leak detection monitoring
devices. The vendor survey, however, was successful
in gaining information from approximately 70 percent
of the vendors that were queried. Except for a notable
lack of data regarding any common interference,
operational, or maintenance problems, vendor
responses were generally thorough.
A total of 49 vendors was identified that manufacture
devices related to the out-of-tank measurement of
petroleum hydrocarbon spills or leaks from UST
installations. Vendor specifications were received for
63 of 69 (91 percent) different products. Survey forms
were completed by 30 of the 42 vendors that were
queried. Survey forms were received for 44 of the 62
(71 percent) devices covered by the survey.
Vendor responses provided a basis for dividing the
external (out-of-tank) leak monitoring devices for UST
systems into four categories: intermittent liquid-phase
detection, intermittent gas-phase detection,
continuous liquid-phase detection, and continuous
gas-phase detection. An examination of vendor
survey datr, yielded the following information:
o Commercial external (out-of-tank) leak monitors
are designed primarily to detect leaks or spills of
petroleum hydrocarbons;
o Most leak monitoring systems cannot immediately
distinguish between surface spills and leaks;
o Most leak monitoring devices do not measure leak
rates, although some devices (gaseous detectors)
are capable of measuring hydrocarbon
concentrations;
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o No uniform performance specifications exist for
external leak monitoring devices;
o Most leak monitoring systems require the
installation of observation wells or boreholes;
o Vendor responses were limited with regard to:
- Operational problems,
- Interferences,
- Maintenance problems, and
- Performance testing procedures;
o Most leak monitoring systems can be retrofitted at
existing LIST installations;
o Intermittent monitoring techniques are more labor-
intensive than continuous techniques, but may be
more reliable;
o Gas-phase detection can be more sensitive than
liquid-phase alarms and subject to interferences;
o Equipment and installation costs (for permanent
external leak detection systems) may vary
considerably, as these costs are dependent on the
type of devices selected and the number of
sensors used in each installation, local
construction codes and permitting costs, and local
labor costs; and
o Operational and maintenance costs for permanent
external leak monitoring systems may also vary,
but are thought to be low, on the basis of
information obtained from equipment vendors.
The performance characteristics for each leak
detection category are summarized in Table 1. The
data presented in Table 1 are based on information
obtained from vendors and have not been verified by
independent testing; therefore, these data may be
biased.
vi
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Table 1
Characteristics of Leak Detection Sensors*
Leak Detection Category
Type of Compounds
Detected
Detection Adjustable
for Specific
Compounds
Potential
Interferences
Severity of
Interferences
False Positives or
Negatives
Temperature Range
Can Systems Be
Retrofitted?
Are Wells Required?
Can Devices Be
Used in Wet Soils?
Years on Market
Detection Limits
I Lower
1
Upper
1 Response
1 Characteristics
1 Lag Time
Rise Time
Fall Time
Drift
Precision
Intermittent
Liquid-Phase
Liquid hydrocarbons
Generally not
None
Low
Unlikely
>0°C
Yes
Yes
Yes
>5
1/64 to 1/32 in.
None
N/A
N/A
N/A
N/A
N/A
•NOTE: The information presented in this table
not on actual performance data which has been
**LEL - Lower Explosive Limit
Continuous
Liquid-Phase
Vapor/liquid
hydrocarbons
Generally not
Physical and
chemical
Variable
Unlikely
-45to120°C
Yes
Usually
Yes
0-15
1/32 to 1/8 in.
None
1 sec. to 10 hr.
1 sec to 60 sec.
1 sec. to ?
N/A
Unknown
is based on information
independently verified.
Intermittent
Gas-Phase
Hydrocarbon
vapors
Varies between
techniques
Chemical
Potentially high
Both possible
-20to60°C
Yes
Usually
Yes
2-10
0.1 to 1500ppm
2000 ppm to
100%LEL"
1 sec.
3 sec. to 30 sec.
5 sec. to ?
Negligible to
<1%/day full scale
5% to unknown
provided by vendors of
Continuous II
Gas-Phase ||
Hydrocarbon II
vapors I
Generally not II
Chemical II
Potentially high
Both possible
-70 to 70°C
Yes
Usually
Yes
0-20
1 0 to 1 00 ppm
1%to
100%LEL"
1 sec. to 10 min.
1 sec. to 20 sec.
20 sec. to several
minutes
Negligible to
<1%/day full scale
5% to unknown
monitoring devices and
vii
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SECTION 1
Introduction
1.1 Background
Underground storage tanks (USTs) and their
associated piping represent a major potential source
of environmental contamination. If not detected, leaks
of stored petroleum hydrocarbons can migrate through
the soil and can contaminate ground-water supplies.
Petroleum product leaks can accumulate underground
and can result in an explosion or in exposure hazards
that are due to the migration of volatile organic vapors
through the soil into basements, sewers, and utility
vaults. Of the estimated 3 to 5 million underground
hazardous substance storage tanks currently in the
United States, 1.4 million are used to store
gasoline1.2. As many as one-quarter of the
underground (steel) storage tank systems (tanks and
piping) may be leaking3. More than 95% of all tank
leaks are caused by the corrosion of steel
components, with tanks over 10 years old being the
most susceptible to corrosion4. Leaks in piping are
commonly due to one of several factors, including
corrosion, faulty installation, accidents, and
environmental stresses (such as frost heaves). The
problem is particularly acute because most
underground tank systems are made of unprotected
steel and are an average of 12 years old. Several
major oil companies have sought to minimize
environmental effects from leaking underground
storage tanks by systematically replacing existing
tanks and piping with new corrosion-resistant
fiberglass or fiberglass-reinforced plastic (FRP)
systems, FRP-clad steel tanks, or with coated and
cathodically protected steel tanks. However, the large
number of tanks in existence, as well as several well-
publicized leaks, has prompted Congress to include
the regulation of underground storage tanks under the
Resource Conservation and Recovery Act (RCRA).
Subtitle I of the 1984 Hazardous and Solid Waste
Amendments to RCRA requires that the U.S.
Environmental Protection Agency (EPA) establish a
comprehensive program for the regulation of new and
existing underground storage tanks. Specifically, this
law requires that federal and state regulatory
programs include "requirements for maintaining a leak
detection system, an inventory control system together
with tank testing, or a comparable system or method
designed to identify releases in a manner consistent
with the protection of human health and the
environment"6. The law covers underground storage
tanks holding all substances regulated under the
Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) as well as
petroleum products (except for hazardous waste
storage tanks already regulated under Subtitle C of
RCRA).
The U.S. EPA has established the Office of
Underground Storage Tanks to oversee the regulatory
effort for controlling UST system leaks. The EPA has
initiated work to estimate the number of tank systems
currently leaking, to evaluate tank and piping integrity
(tightness) tests and other inside-the-tank leak
detection methods, and to evaluate out-of-tank leak
monitoring methods. The Environmental Monitoring
Systems Laboratory (EMSL) of the U.S. EPA in Las
Vegas is responsible for developing the technical
background necessary for developing regulations for
leak monitoring. A project team consisting of several
contractors assembled by EPA-EMSL will perform a
number of functions including: collection and
evaluation of user and vendor data, determination of
typical background soil contamination levels, and
examination of transport mechanisms for vapor and
liquid pollutants.
Radian Corporation, under EPA Contract No. 68-02-
3994, is assisting EPA-EMSL in developing
performance criteria and certification procedures for
commercially available external petroleum leak
monitoring methods. This, document reports the
findings from a survey of vendors of out-of-tank leak
monitors using a standardized questionnaire. The
information compiled on the number, type, and
performance capabilities of available leak monitors
may be used later to establish performance standards
and certification procedures.
1.2 Program Objectives
The primary objectives of the Phase I study were to:
o Classify out-of-tank leak detection sensors for
petroleum hydrocarbons by function and type
and establish performance categories for each
classification group of leak detection devices;
1-1
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o Identify ranges for performance categories
applicable to each classification of petroleum
hydrocarbon leak detection by using vendor-
supplied data; and
o Provide input to future development of
procedures for certifying the performance of
petroleum hydrocarbons out-of-tank leak
detection sensors.
This document serves as a background reference on
external leak monitoring. It is not a guidance manual
for selecting an external leak monitoring device for
LIST systems. Rather it attempts to provide an
introduction to the topic and to give an underground
storage tank owner the necessary background to ask
pertinent questions, seek more information, and assist
the owner in making an informed choice.
1.3 Scope of Work and Report Outline
To meet the objectives of this study, a four-step
program was performed. First, a literature search was
conducted to identify relevant sources. From these
sources, a list of vendors was developed. The third
step involved developing and mailing out
questionnaires to identified vendors to solicit
information on leak monitoring devices. The fourth
step involved collecting and evaluating these data and
reporting the findings. Although an attempt was made
to identify and communicate with as many vendors as
possible, the resultant vendor list was not all-inclusive.
Furthermore, no attempt was made to verify the claims
made by the manufacturers or to limit the survey to
"proven" UST leak monitors.
Conclusions and a summary of results are presented
in Section 2. Section 3 provides a discussion of
pertinent issues such as network design and data
analysis. The technical approach is described in more
detail in Section 4. Section 5 presents the results of
the Phase I work. Section 6 lists the references cited,
and Section 7 contains a bibliography. Supporting
data are given in the appendices. Appendix A lists the
products, technical representatives, telephone
numbers, and addresses of the particular vendors.
Appendix B contains a copy of the vendor survey
questionnaire.
1.4 Overview of Leak Detection and Tank
System Design
The following discussion provides a brief overview of
underground storage tank systems and practices. It is
intended for individuals unfamiliar with these topics.
Readers are encouraged to consult the publications
listed in the bibliography in Section 6 for more
information. When leak detection devices are chosen
for a given underground installation, it is important to
consider site-specific factors and the equipment
chosen for each system component. The following
discussion provides background information about the
generic types of equipment available for underground
storage tank systems.
1.4.1 Leak Detection
A variety of programs can be followed to detect leaks
or spills from underground storage tanks and piping
including: inventory control, tank and line integrity
testing, and leak monitoring. Leak monitoring includes
interstitial monitoring of double-walled tanks, areal
surveillance, and use of observation wells in the
backfill material. This report covers in detail only the
last category of leak monitoring techniques. Other
programs and types of leak monitoring are briefly
discussed below.
1.4.1.1 inventory Control Inventory control typically
involves daily measurements of volume of stored
product in each tank and monthly reconciliation of the
current tank volume to the input and output records.
Volume checks are made either manually by using a
gauge stick or automatically by using an electronic
level monitor. Detailed recommendations for inventory
control procedures have been set forth by the EPA?
and the American Petroleum Institute8. Inventory
control, which can detect large leaks, makes good
business sense. However, since this technique may
not be accurate enough to satisfy the more stringent
state and local leak detection regulations, it is often
used in conjunction with integrity testing or leak
monitoring programs. Electronic inventory control
systems improve the accuracy of this technique to
detect leaks from underground storage tanks and
associated piping.
1.4.1.2 Integrity Testing Integrity (tightness) testing
of tanks and pipes involves a point-in-time
determination of whether leaks are present in an
underground storage tank system. The tests fall into
two general categories: quantitative and qualitative
tests (sometimes called volumetric and non-
volumetric). Either type of test requires the use of
specialized equipment and may require shutdown of
the facility for up to a full day. Most current
regulations specify that a quantitative rather than a
qualitative integrity test be performed.
Quantitative tests measure leak rates. These tests
monitor changes in product volume by measuring
parameters associated with volume changes
(including changes in liquid level, temperature,
pressure, and density). A number of factors such as
temperature stratification within the tank, tank
1-2
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deformation, vapor pockets, etc., may obfuscate the
test results. It is important to use trained test
operators who are experienced in identifying and
correcting for common test interferences. The current
industry recommended practice, as specified by the
National Fire Prevention Association (NFPA), is the
ability to measure a leak rate of 0.05 gal/hr in tanks of
less than 12,500 gallons. The validity of this standard
and the ability of various test methods to meet this
standard are currently being investigated by the EPA.
Qualitative tests, which involve monitoring either the
sounds associated with leaking product or the
diffusion of a tracer gas (e.g., helium) introduced into
the tank, determine the presence of leaks. These
tests do not quantify leak rates. Qualitative tests are
not necessarily less sensitive than the quantitative
tests. The underlying assumption is that since any
leak can be significant over time, determination of a
leak rate is not necessary. The most prevalent type of
qualitative test uses helium as a tracer. One limitation
of this type of test is that the tracer gas is a smaller
molecule than the stored product, and it may pass
through fittings or other openings that are liquid-tight.
1.4.1.3 Leak Monitoring Interstitial monitors, used
with double-walled underground storage tanks,
monitor for fluid or pressure changes. Some external
continuous leak monitoring systems can be adapted
for use as interstitial monitors.
Area-wide surveillance methods include a number of
different approaches and techniques. Their typical
application is mapping contaminant plumes from
spilled hydrocarbons, but they can also be used for
leak monitoring. Included in this category are soil core
analysis, soil gas analysis, dyes and tracers methods,
surface geophysical techniques, monitoring well
networks, and other miscellaneous techniques.
1.4.2 Tank System Design
Figure 1-1 illustrates a typical underground storage
tank system. Although underground storage tank
systems have a number of features in common,
several major design options or site characteristics
must be considered when evaluating leak detection
options. Section 4 discusses the effects of the various
design options on the selection of a monitoring
approach.
1.4.2.1 New Versus Old System The best time to
develop a leak detection program is concurrently with
the selection of tanks and associated piping. This
allows the system designer maximum flexibility.
Considerations include providing a sufficient number
of tank openings for potential use of level detectors or
integrity test equipment, or providing for monitoring
with observation wells. Existing UST systems offer
the designer fewer options. For example, it is
normally prohibitively expensive to retrofit secondary
containment. For many existing tanks, implementing a
periodic integrity test schedule and using inventory
control may be preferable to retrofitting for leak
monitoring capability.
1.4.2.2 Tank and Piping Type Two tank materials
are most commonly used: steel and fiberglass. Each
is capable of adequate performance under the proper
conditions. Since corrosion is the most common
cause of leaks in steel tanks, older, unprotected steel
tanks in corrosive soils are most at risk and are the
most likely to benefit from an integrity test/leak
monitoring program. At new steel tank installations,
the tanks should be coated and cathodically protected.
Other types of tanks that are protected from corrosion
include FRP and composites. The composite tanks
have a steel inner tank with a thick external coating of
FRP.
Piping has been built in the past with carbon or
galvanized steel. Coated and cathodically protected
steel piping and FRP piping are now commonly used
at new installations.
1.4.2.3 Secondary Containment Several types of
secondary containment have been used in UST
systems: double-walled tanks, clay liners, concrete
vaults, and synthetic liners. The use of secondary
containment is advisable for environmentally sensitive
areas. Secondary containment prevents leaked
product from migrating out of the near-tank area
before remedial measures can be taken.
A double-walled tank is a tank within a tank, with a
small enclosed space separating the two. It is a
relatively simple matter to monitor the annular space
between tanks for leaks. External leak detection (e.g.,
observation wells) and integrity testing are not
normally necessary for double-walled tanks.
Liners usually consist of a rubber or polymer
membrane that lines the tank or piping excavation.
Tanks and piping are placed in the hole and backfilled.
Observation wells are typically placed within the lined
hole to allow leak detection.
Concrete vaults around USTs are mandatory in some
states under certain conditions. Since concrete is not
an impenetrable barrier to product liquid and vapor
transport, it should be lined or coated.
1.4.2.4 Overfill Protection The area around
underground storage tanks can become contaminated
from the accumulation of small surface spills. The
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TANK TRUCK
OVERFILL PREVENTION DEVICE fi\
VAPOR RECOVERY LINE
PRODUCT
DISPENSER
CORROSION-RESISTANT
STORAGE TANK
AUTOMATIC
SHUTOFF
VALVE
PRODUCT DELIVERY LINE
MATERIAL
LEAK DETECTOR
T) SUBMERGED PUMPASSEMBLY
Well designed underground storage systems usually contain the following:
(1) corrosion resistant tank; (2) striker plate under tank fill line; (3) submerged pump with leak detector on product
delivery line; (4) float vent valve in tank vent line; (5) excavation walls and floor of impervtaus material; (6) asphalt or
concrete excavation cap; (7) automatic shutoff valve on delivery line at pump island; (8) overfill prevention device at
fill line on tank truck; (9) vapor recovery in tank truck during filling operation; (10) observation wells located inside
excavation boundaries; (11) pea gravel or sand fill for excavation.
These are all important aspects of a good underground storage system.
Figure 1-1
Elements of an Underground Storage Tank Installation^
major cause of such spills is overfilling the tank during
liquid transfer operations. This problem can be
minimized by using in-tank level sensors, dry
couplings on transfer lines, or catchment basins
around fill pipes. In installations without overfill and
spill prevention systems, it may be difficult to use
vapor sensing devices for leak monitoring because of
the build-up over time of high background levels of
vapor in the soil. This problem may be overcome
through the use of compound-specific tracers to
assess tank system integrity.
1A2.5 Dry Versus Wet Excavations Most UST
installation excavations are dry holes. However, in
areas of high groundwater, the hole may be wet some
or all of the time. In wet-hole systems, external leak
detection systems that detect liquid product and that
can differentiate between petroleum hydrocarbons and
water are preferred. Also, because the water in the
hole may enter the tank, the leak detection system can
be augmented by monitoring the water layer in the
tank as part of inventory control. Site geology, other
than ground-water levels, should not significantly
affect the selection of a leak monitoring system if the
leak monitor is placed in the porous backfill material.
The type of leak monitoring collection system used
depends on the depth to groundwater and on the local
variability in ground-water level. Some industry trade
groups currently recommend using two observation
wells per excavation for areas of shallow groundwater
(or one well and secondary containment) as in Figure
1-2. For areas with deep groundwater, vapor wells
may be used to monitor for leaks as depicted in Figure
1-3.
1-4
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Well Outside
Tank Excavation
Finished Grade
Well In Tank
Excavation
Grout I
Seal I
Waterproof Caps
Capable of Being
Sealed and Locked
_CL
1'Min.
Tank Spacing and Fill in Accordance
With Tank Manufacturer Specifications
Slot Size 0.020"
Groundwater
t
5' Min.
Observation Wells: Each Well is 2" Min. Dia. PVC Pipe
Slotted From 2' Below Ground Surface to Bottom.
Wells Inside Excavation Are Installed to Bottom of Excavation.
Wells Outside Excavation Are Installed Either 5' Into Groundwater or
2 Feet Below Bottom of Tank, Whichever is Deeper.
V
Figure 1-2
Example of Observation Well Installation10
1-5
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Backfill
'N
A
A
•^ Manwa
A n A
Perforated
• PVC
Water Table
CAP
Figure 1-3
Example of Vapor Monitoring Well
1-6
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SECTION 2
Conclusions and Summary of Results
2.1 Conclusions
Response to the vendor survey accounted for
approximately 71 percent of the identified vendors.
The response was almost universal from vendors of
equipment marketed specifically for LIST applications.
The literature search conducted in 1986 as part of this
study clearly demonstrated a lack of useful, published
information regarding external (out-of-tank) petroleum
leak monitoring devices and a need for the current
program to be performed. Although much valuable
information was gained from this study, additional
work will be necessary before performance standards
and certification procedures can be developed for
each category of leak monitoring techniques.
Vendor responses to the questionnaire provided a
basis for dividing the petroleum leak monitoring
techniques Into four basic categories: intermittent
liquid-phase detection, intermittent gas-phase
detection, continuous liquid-phase detection, and
continuous gas-phase detection. Sufficient
information was received from the vendor survey to
assess and compare the performances of the four
general types of techniques and, to a lesser extent, to
compare one technique with another. However,
insufficient data exist to adequately compare the
product of one vendor with the product of another
vendor when both are based on the same principle of
operation. Also, the vendor responses were
inadequate in two important areas: (1) description of
common interferences and operational or
maintenance problems and (2) provision of
certification procedures.
Caution should be observed when evaluating monitor
performance based solely on vendor-supplied data.
Additional data based on independent third-party
evaluations and on the operating experience of actual
users is needed to support the development of
performance specifications for out-of-tank leak
detection monitors.
2.2 Summary of Results
A summary of the results of this investigation is
provided below.
2.2.1 Summary of General Findings for
External Leak Monitoring Systems
All of the external leak monitoring systems for
petroleum hydrocarbons shared some design
requirements, detection limitations, installation
options, and maintenance claims, according to
vendors. The external leak detection devices usually
require monitoring wells or boreholes placed
downgradient in the excavation pit. The devices are
all designed for use with hydrocarbon products,
though they may work with other materials. They can
all be retrofitted at existing installations. Finally, all
vendors state that low or no maintenance costs are
typically incurred.
2.2.2 Summary of Findings for Intermittent
Liquid-Phase Detector
Intermittent liquid-phase petroleum leak detectors for
USTs are inexpensive ($10 to $100) and simple to
operate. They are currently marketed and are widely
used. They can neither detect vapors nor provide
nonspecific detection of liquid hydrocarbons. The
vendors list no potential interferences; therefore
(based on vendor information alone), the potential for
false readings is low. The devices respond to
approximately 1/32 to 1/64 inch of product. The
usable life for these types of sensors varies from
necessary replacement upon detection to indefinite.
2.2.3 Summary of Findings for Continuous
Liquid-Phase Detectors
Continuous liquid-phase petroleum leak detectors for
USTs have been on the market for up to 15 years, and
some vendors have thousands of devices in current
use. Costs range from $400 to $1,500 for control
panels and from $100 to $700 for sensors. Estimates
for installation costs vary widely. Product-soluble leak
detection devices will respond to both liquid and
vapors. Most continuous liquid sensors respond to 1/8
to 1/32 inch of liquid within 0 to 10 hours (once liquid
comes in contact with the sensor). Some potential
interferences include hydrocarbons, ultraviolet (UV)
light, water vapor, ice, and reduced sulfur compounds.
False positive readings may be caused by these
interferents and, in some models, by algae or
2-1
-------
mechanical failure. The control boxes can usually
accommodate multiple sensors and have a long
service life.
2.2.4 Summary of Findings for Intermittent
Gas-Phase Detectors
Intermittent gas-phase petroleum hydrocarbon leak
detectors for USTs have been commercially available
for up to 10 years, and some vendors have hundreds
to thousands in current use (not necessarily for UST
systems). Costs range from $100 to $1,700 for
sensors. Estimates for installation costs vary widely.
Some gas-phase leak detectors (e.g., GC's) give a
compound-specific response. Detection limits range
from low part per billion (ppb) to 1,500 part per million
(ppm) for the lower limit up to 10 percent to 100
percent of the lower explosive limit (LEL) for the upper
limit. Response time is normally within seconds. A
number of gas species may act as interferents, and
both false positive and false negative readings are
possible. The control panels have a long service life,
but generally they can accommodate only one sensor.
These types of detectors may involve appreciable
labor costs and may require special maintenance.
2.2.5 Summary of Findings for Continuous
Gas-Phase Detectors
Continuous gas-phase petroleum hydrocarbon leak
detectors are generally new to the underground
storage tank market, and few are in current use.
However, thousands of these types of detectors have
been in use for up to 20 years in other applications.
Costs range from $500 to $5,000 for control panels
and from $65 to $1,500 for sensors. Installation costs
vary widely. Certain devices within this category give
compound-specific responses. Detection limits range
from 10 to 100 ppm at the lower end up to 100 percent
of the lower explosive limit (LEL). Response time is
very rapid. A relatively large number of interferences
were given, and both false positive and false negative
readings are possible. The control boxes can usually
accommodate multiple sensors and have a long
service life. Sensor life ranges from 1 to 10 years.
2-2
-------
SECTION 3
Technical Approach
The technical approach to this project consisted of a
literature search, compilation of a vendor list, a vendor
survey, and evaluation of the data collected from this
survey. Each of these tasks is described below.
3.1 Literature Search
A literature search was performed to identify and
obtain published documents relating to the UST field
in general and to out-of-tank leak monitoring methods
in particular. In addition, several researchers active in
the area were asked for status reports of their current
projects, and product literature was solicited from
vendors. Only limited information regarding
commercially available leak monitoring systems was
obtained from the literature; this information is listed in
the bibliography in Section 6.
3.2 Vendor List
A vendor list was generated to facilitate the vendor
survey (see Appendix A). The list, based on vendor
information obtained from the open literature and from
other researchers, was augmented by information
from other Radian projects, the Project Officer, and
telephone inquiries. Each vendor was called to
ascertain what product(s) are currently marketed for
UST applications and to obtain product literature.
3.3 Vendor Survey
A vendor survey was performed to gather specific
information regarding performance data for each type
of out-of-tank sensing device currently in use. The
specific types of performance information requested
included specificity, threshold detection, response
time, interferences, drift, precision, noise,
recommended operating environment, and service life.
These terms, defined in the glossary, are important
because they are the major categories by which
system performance can be evaluated. Other data,
including capital cost, recommended installation and
operation procedures, and maintenance costs, were
also obtained from the vendor survey. These data
were used to develop generic performance categories
for each leak detection classification group(s) and
performance ranges for each performance category.
The questionnaire format can be found in Appendix B.
3-1
-------
-------
SECTION 4
Results
This section presents and discusses the results of the
vendor survey. Section 4.1 gives general information
regarding the survey. Vendor responses to the survey
are tabulated in Section 4.2, and summary tables and
tables listing the responses of each vendor are
presented. The leak monitoring devices are evaluated
in Section 4.3, and the results are discussed in
Section 4.4.
4.1 Discussion of Survey
Table 4-1 shows the vendor list generated for this
project. The leak monitoring systems listed include
both systems designed and marketed specifically for
UST applications and general analytical equipment.
The list is as complete as possible, though it is
probable that additional vendors exist. Only
commercially available leak monitoring techniques
were considered in this study. Appendix A lists the
mailing address, telephone number, and technical
representative for each vendor. Vendors identified
since the survey was completed are included in
Appendix A, but not in Table 4-1. Each vendor was
called to determine which products were being
marketed or would be most suitable for UST
applications. A questionnaire was sent in early 1986
to each vendor, except for vendors of grab sampling
equipment, chemical-sensitive pastes, and detector
tubes. These types of monitoring devices were
thought to be sufficiently simple so that no information
other than that contained in the product literature was
deemed necessary. As can be seen in Table 4-1,
vendors who market products in several categories
sometimes completed questionnaires for only one
product, implying that this was the product they
emphasized in their marketing. Also, it should be
noted that two vendors chose not to participate in the
survey and that several other companies did not
submit responses.
A total of 49 vendors offering a total of 69 products
related to leak monitoring for UST systems were
identified. Product literature was received for 63 (91
percent) of the products. Survey forms were
completed and returned by 30 of the 42 (71 percent)
vendors queried. Survey forms were completed and
returned for 44 of the 62 (71 percent) products
covered by the survey. Survey forms were also
received from three vendors of interstitial monitors:
Raychem, Emco Wheaton, and Perma-Pipe. Their
devices respond to the presence of petroleum
hydrocarbons as opposed to interstitial monitors that
detect pressure or liquid-level changes. They are,
therefore, very similar to external monitoring devices
(and, as noted earlier, some external monitoring
devices are suitable for use as interstitial monitors).
However, these devices fall outside the scope of this
project, and therefore, these survey responses are not
included in this compilation. A second device offered
by Emco Wheaton is suitable for external monitoring
and is included in the study.
The EPA Office of Underground Storage Tanks
(OUST) has compiled a list of leak detection methods
and manufacturers that contains over 250 products.
The OUST list includes the vendors and products
identified in this document, as well as integrity test,
inventory control, line detector, and annular space
monitoring methods that are outside the scope of this
study.
4.2 Tabulated Results From Survey
This section describes the principle of operation of
each leak monitoring technique and is followed by a
series of tables summarizing the vendor responses to
the questionnaire.
4.2.1 Principle of Operation
The principle of operation for each leak monitoring
device listed in Table 4-1 is discussed below. The
discussion of the principles of operation has been
published previously7. The devices fall into four
categories according to whether they detect gases or
liquids, intermittently or continuously, as depicted in
Table 4-2.
The sampling approach required varies among the
four categories of leak monitoring devices. Liquid-
phase techniques require a monitoring well screened
at the surface of the groundwater table or connected
to a collection sump. Continuous liquid-phase
techniques use some type of sensor installed in the
monitoring well to monitor the liquid-air interface.
Intermittent liquid-phase techniques involve either
temporarily placing a sensor in the monitoring well or
removing an aliquot of the well water with a bailer or
4-1
-------
Type of Detector/
Company
Intermittent Liquid-Phase
Chemical-Sensitive Paste
Kolor Kut Products
McCabe
Grab Samplers
NEPCCO
Norton
Continuous Liquid-Phase
Interface Probe
Comar, Inc.
EMTEK, Inc.
Marine Moisture Control
Oil Recovery Systems, Inc.
Product-Soluble Devices
EMTEK, Inc.
IFP Enterprise
In-Situ, Inc.
K&E Associates
Pump Engineer Assoc.
Technology 2,000, Inc.
Electrical Resistivity Sensors
Total Containment
Thermal Conductivity Devices
Leak-X
Oil Recovery
Systems, Inc.
Pollulert Systems (Mallory)
Universal Sensors
and Devices, Inc.
Table 4-1
List of Vendors and Response to Survey
Literature Survey
Device Name/Model Number Received Received Comments
Water & Gasoline Finding Pastes
Water & Gasoline Indicator Pastes
Liquid Samplers3 and Bailers
Bailers3
Model 807 Tank Monitor
Model 808 Tank Monitor
Model 809 Tank Monitor
PLD-17 Pipeline Monitor
Electronic Well Gauging3 Light (EWGL-12)
Sonic Ullage Interface3 Probe
Interface Probe'3
Detect ran
Oil Fuse
Petrochemical Release Monitor
PMS-800
Sentinel
TOLTECH Hydrocarbon Monitor
Total Containment Cable-TC3000
Leak-X System
CMS Variable Level System
FD102andFD103
Leak Alert System
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
—
X
X
n/a
n/a
n/a
n/a
X
X
X
X
~
-
X
"
X
X
«
X
X
X
—
X
X
4-2
-------
Table 4-1
List of Vendors and Response to Survey (continued)
Type of Detector/ Literature Survey
Company Device Name/Model Number Received Received Comments
Intermittent Gas-Phase
Combustible Gas Detectors
MSA
Detector Tubes
MSA
National Draeger, Inc.
FIDs
Foxboro Analytical
Portable GCs
AID, Inc.
HNU
Microsensor
Technology Inc.
Photovac, Inc.
Sentex Sensing Tech., Inc.
XON Tech
Infrared
Foxboro Analytical
Horiba Engineering
PIDs
AID, Inc.
Astro Resources
HNU
Photovac, Inc.
Continuous Gas-Phase
Catalvtic Sensor Devices
Bacharach Instrument Co.
Gas Tech, Inc.
"* " ~ "* "^ «^— •—
Several models3
Samplair Pump & Test Kit3
Gas & Vapor3 Detection Products
Century OVA3
Model 5903
Models 201, 301 D, 501 a
Michromonitor3
Photovac 10A103
Scentor3
GC-8103
Miran3
IR Hydrocarbon3 Gas Analyzer
Model 580a
Trace Gas Analyzer-1 01 03
Model P1 1 01 3
TIP3
Underground Tank Monitor
TLV Sniffer3
Model 303a
Model H Gaspointer3
Model 12383
^^"""^^^^•^ """^^"""•••^^^••••^^••••••^^••••"••^••••••••••^••B
X
X
X
X
X
X
X
X
X
~
X
X
X
X
X
X
X
X
X
X
n/a
n/a
X
X
•<•
X
»
X
~
X
X
X
X
X
X
X
X
X
-
4-3
-------
Table 4-1
List of Vendors and Response to Survey (continued)
Type of Detector/
Company Device Name/Model Number
Industrial Scientific Devices LD-2223
Intek Corp. IGD
Lumidor Safety Products Model CRP-1
Rexnord Gas Detection Combustible Gasa Detection System
Products
Diffusion Sensors
Adsistor Technology Adsistor Sensor3
Emco Wheaton Leak Sensor II Vapor Probe
EMMCO Enterprises Env. Control Safety Monitoring System
Spearhead Tech., Inc. STI 2X12 Inground Tank Monitor
Metal Oxide Semiconductors
Armstrong Monitoring 4200 Sensor
Azonic Technology Corp. Enviro-Ranger
Calibrated Instrument, Inc. Pure Air Monitor
Enmet Corp. Several models3
Genelco, Inc. Soil Sentry
Harco Corp. Multi Ram 12
International AG5000 & AG51 00a
MSA Tankgard
Oil Recovery Systems, Vapor CMSb
Inc.
Universal Sensors Leak Alert
and Devices, Inc.
U.S. Industrial Products Co. Tank Monitor
Product-Permeable Devices
Teledyne Geotech LASP System
W.L Gore LEAKLEARN
Literature
Received
X
X
X
X
X
X
X
X
X
X
X
X
X
-
X
X
"-
X
X
X
X
Survey
Received
X
X
~
X
X
X
X
X
X
X
X
X
X
-
-
X
"
X
X
X
Comments
Vendor will
not respond
to survey
Vendor will
not respond
to survey
3 Not marketed specifically for UST applications.
b Not known if product marketed specifically for UST applications.
4-4
-------
pump. Monitoring devices that collect pore liquids
(e.g., suction cup lysimeters) in the vadose zone are
being examined by another member of the EPA-EMSL
project team. These devices are currently marketed
commercially but not to routinely monitor leaks or
spills from underground storage tanks. Gas-phase
monitoring techniques--both continuous and
intermittent-generally involve some type of extractive
pump and sensor. The sample is drawn from the
headspace of a monitoring well or from some type of
soil probe and is moved to a control box containing the
sensing element. However, in some of the continuous
gas-phase techniques, the sensing element may be
below ground, and an extractive pump is not
necessary, though its use will increase the vapor
transport rate and will shorten the detection time.
Principle of Operation - Intermittent Liquid-Phase
Detection Techniques
Chemical-sensitive pastes. Separate pastes that
change color in the presence of liquid water and
hydrocarbons (gasoline or oil) are available for
sampling observation wells or tank contents. The
Table 4-2
Commercially Available Leak
Monitoring Techniques
Monitoring
Category3 Technique
Intermittent 1. Chemical-sensitive pastes
Liquid-Phase 2. Grab sampling
Intermittent 1. Combustible gas detector
Gas-Phase 2. Detector tube
3. Flame-ionization detector
4. Portable gas chromatograph
5. Infrared detector
6. Photoionization detector
Continuous 1. Interface probe
Liquid-Phase 2. Product soluble device (includes
electrical resistivity detectors)
3. Thermal conductivity device
Continuous 1. Catalytic sensor
Gas-Phase 2. Diffusion sensor
3. Metal-oxide semiconductor
4. Product permeable device
aTypical use of technique. There is some overlap
between intermittent and continuous techniques.
paste(s) is spread in a thin layer along a weighted
tape measure. The tape measure is lowered into the
well or tank until the bottom is reached. The tape is
retrieved, and the level of the various liquid layers
present is read directly from the tape.
Grab sampling. Grab sampling of liquid samples is
usually performed by using a bailer, i.e., a Teflon,
plastic, or stainless steel pipe with a ball valve in the
bottom, as in Figure 4-1. The thickness of any product
layer is determined visually, and samples may be
decanted for more detailed analysis as required.
Principle of Operation - Intermittent Gas-Phase
Detection Techniques
Combustible gas detectors. In combustible gas
detectors, a sample gas-air mixture comes in contact
with a heated, catalytic filament. The burning sample
gas raises the temperature of the detector and,
consequently, results in a corresponding increase in
electrical resistance. The change in electrical
resistance is proportional to concentration and can be
measured with a Wheatstone bridge or equivalent
Lifting
Line
/\
Clear Acrylic
Bailer with
Graduations
On Side
Check Ball
Figure 4-1
Bailer Used for Grab Sampling
4-5
-------
Principle of Operation
Beam Trimmer
Reference Cell
Preamplifier
Control Unit
Amplifier
Figure 4-2
Schematic of an Infrared Radiation (IR) Detector9
Collector Electrode
Compression Spring
Lamp Housing
Lamp
High Voltage Contact
Lamp Window
lonization Chamber
Detector Exit
Bias Voltage
Sample Inlet
Figure 4-3
Schematic of a Photolonization Detector (P1D)10
4-6
-------
electronic circuit. Combustible gas detectors are not
sensitive to low levels of hydrocarbon vapors and are
susceptible to catalyst poisoning from lead or other
interferents.
Detector tubes. The headspace of observation wells
can be monitored by using detector tubes. The
sample is collected via a hand-operated bellows pump
or an automated battery-powered pump. The sample
gas passes through replaceable glass tubes filled with
an inert support that has been impregnated with
chemicals designed to produce a colorimetric
indication in the presence of selected gases, vapors,
or aerosols. Detector tubes for a variety of gas
species and measurement ranges are available.
Flame-ionization detectors. The flame-ionization
detector (FID) operates on the principle that most
organic compounds are pyrolyzed when introduced
into a hydrogen-oxygen flame and that ions are
produced as part of the process. A charged electrode
collects the ions, and the resulting current is
measured. FIDs show good response to methane and
other aliphatic compounds.
Portable gas chromatographs. In gas chromatography
(GC), sample gas is transported by a carrier gas over
Compressed Air
Cylinder
Alarm Relay
Pressure
Drop Sensor
a stationary solid- or liquid-phase material. The
sample is chromatographically separated into its
various components, and each compound is
sequentially detected at one or more gas detectors.
GC permits both monitoring for the presence of
hydrocarbon species and identification of the
hydrocarbons present. Several of the available
portable field GCs require no external support
equipment such as compressed gas cylinders, AC
power, integrator, etc. Sample collection can be
accomplished by using gas-tight syringes, sorbent
cartridges, evacuated stainless steel canisters, or
polymer gas bags.' Most GCs require injection of sub-
mL sample volumes and do not contain an extractive
pump for continuous sample monitoring.
Infrared detectors. Infrared radiation (IR) detectors
are based on the absorption of infrared radiation by
covalent bonds that result in increased vibrational or
rotational energy in the gas molecule. A typical
instrument contains an IR lamp source, sample and
reference cells, filters, and an infrared light-sensitive
detector, shown in Figure 4-2. The light is split and
passes through both bells simultaneously. Any
difference in power between the two outlet beams is
due to absorbance by the sample and is sensed by
the detectors and read out as concentration. The
Air Line
Ground
Surface
Groundwater
Level
SBC Walled
Tube
Monitor Well
Figure 4-4
Schematic of Leak Monitoring System Using
Product-Soluble Pressurized Tube7
4-7
-------
wavelength of light or the path length of the sample
cell can be varied according to the species being
monitored and to change the sensitivity.
Photoionization detectors. The photoionization
detector (PID) uses a high energy ultraviolet lamp to
ionize the sample drawn into the instrument via an
internal pump. A typical schematic is shown in Figure
4-3. The ionized sample produces an ion current
proportional to concentration which is measured with
an ammeter. The PID is not sensitive to any
compound having an ionization potential greater than
the photon energy from the light source. Insensitive
compounds include methane, ethane, and the major
atmospheric constituents.
Principle of Operation - Continuous Liquid-Phase
Detection Techniques
Interface probes. Interface probes use a combination
of an optical sensor and a thermal conductivity sensor.
The optical sensor works via a pulsed beam of
infrared light being directed down a probe shaft. If the
prism-shaped probe tip is dry, the light is reflected
back up a second shaft where it is detected by a
phototransistor. If the probe tip is immersed in liquid,
the light is refracted into the liquid and therefore
interrupts the signal to.the monitor. A conductivity
sensor is used to determine if any liquid present is
polar or nonpolar.
Product soluble devices. Product soluble devices use
a styrene-butadiene copolymer (SBC) soluble in
gasoline but riot in water. This principle can be used
in a number of ways to detect leaks. One method is to
construct SBC hoses and suspend them in a
monitoring well, shown in Figure 4-4. The hose is kept
pressurized, and the system pressure is monitored.
Any product that encounters the hose will dissolve it
and will create an air leak. The sensitivity of the
detector, which can be varied, depends on product
type, hose thickness, and operating pressure.
Several products are marketed wherein dissolution of
an SBC component activates a mechanical or
electrical alarm, illustrated in Figures 4-5 and 4-6. In
an electrical resistivity sensor, a monitor circuit
continuously reads a resistor at the end of a SBC-
coated conductive cable. The cable contains two
conductor wires, as in Figure 4-7., Degradation of the
SBC coating permits the two wires to touch, and the
touching causes a decrease in resistance. Another
example of an SBC-based system is one that uses a
SBC resin cord connected to a spring-loaded indicator
that is weighted down and placed in a monitoring well.
Dissolution of the SBC causes the weight to be
released and the indicator device to rise and to
activate an alarm.
Thermal conductivity devices. Thermal conductivity
sensors are used for continuous monitoring of liquids.
The sensor floats on the liquid surface in a monitoring
well, shown in Figure 4-8. A heating element in the
float is periodically activated, and the heat loss is
monitored. The differences in heat loss vary between
water (polar) and hydrocarbon (non-polar) compounds
and are detected. The sensor transmits a signal to a
control box to activate a visual or audible alarm when
non-polar liquids are detected. Thermal conductivity
devices have been widely used. Typical maintenance
problems include (1) biological growth on the probe
that insulates it and (2) problems with ice or other
obstructions that prevent the sensor from riding on the
liquid surface.
Principle of Operation - Continuous Gas-Phase
Detection Techniques
Catalytic sensors. Catalytic sensors are a refinement
of the combustible gas detectors described earlier.
They contain a second heated element that has been
coated to be non-reactive with hydrocarbon gases and
that acts as a reference cell.
Diffusion sensors. Diffusion sensors (commonly
referred to as adsistors) are similar in principle to the
MOS detectors described below. Gaseous diffusion
carries sample gases into contact with the adsorptive
material in the sensor; this process changes the
resistance of the sensor. No heating element is used.
The sensor detects any gas with a Van der Waals "a"
constant (a measure of the attractive force between
molecules) above a certain threshold value. The
major atmospheric gases are not detected and are not
interferents.
Metal-oxide semiconductors. Metal-oxide semi-
conductors (MOS) represent one method used for
continuous, gas-phase leak monitoring. A heater and
collector are embedded in a solid-state cell which is
composed of metal and non-metal oxides of transition
elements. At operating temperature, a specific
resistance exists between the sensor elements. Gas
molecules are dissociated into charged ions or ion
complexes on the surface of the sensor. The
resistance of the element junction changes in
proportion to the concentration of certain gas
molecules. Either the sensor is placed in the
monitoring well, or a sample is aspirated to the sensor.
The latter configuration allows one sensor to monitor
several locations.
Product permeable devices. Several materials are
available that are permeable to hydrocarbons
(oleophilic) but not to water (hydrophobic). The best
known of these materials is Gore-Tex°. Two leak
monitoring systems use these selectively permeable
4-8
-------
Spring Loaded Indicator
Ground Surface
Figure 4-5
Schematic of Mechanically Activated,
Product-Soluble Device7
4-9
-------
Ground Surface
Spring Loaded
NC Switch
Figure 4-6
Schematic of Electrically Activated,
Product-Soluble Device7
4-10
-------
To Control
Box or
Next Well
100 Q
Wire Wound
Resistor
Ground Surface
Figure 4-7
Schematic of Electrical Resistivity Sensor Coated
With Product-Soluble Polymer?
4-11
-------
membranes. In one, the membrane surrounds
perforated tubing, shown in Figure 4-9. Gases that
diffuse into the tubing are pumped to a metal-oxide
semiconductor detector (discussed above). The time
delay between initiation of the pump cycle and
detection indicates the location of the leak. In the
second system, the membrane surrounds a coaxial
cable. Oil diffusion through the membrane causes
capacitance changes in the cable and indicates the
presence of a leak. Pulse reflection techniques are
used to locate the position of the leak along the cable.
4.2.2 Other Results
Tables 4-3 through 4-7 summarize the information
provided by vendors. The tables address detection
specificity, detection capability, experience, cost, and
recommended procedures. Vendor responses have
been condensed to a typical response or operating
range per type of monitoring technique, and
information from the product literature and scientific
judgment are also incorporated. Responses from
each vendor are tabulated in Appendix C.
4.3 Evaluation of Results
The division of leak monitoring techniques into
performance categories, the cost-effectiveness of
those techniques, and method selection as a function
of site-specific factors are evaluated in this section.
The evaluation is by type of monitoring system.
Insufficient information exists at this time to evaluate
products within a given system type adequately.
4.3.1 Performance Categories of Leak
Monitoring Techniques
One of the main objectives of this phase of the project
was to divide the large number of commercially
available leak monitoring products into groups of
— to»uff*E
MOH/WKM& WELL 5CXEEN
. OK
ZSTA/NLESS STEEL (MOT SUPPL/ED1
(JfJLEEQKOUND MSTALLATIQN
(TYP/C.AL &ASOLINE
Figure 4-8
Schematic of Typical Installations of Thermal Conductivity Sensor11
4-12
-------
u
n^| total nimmng itmtr i _^— ^— — — —
Running time 1
Corresponds
to Location 1
*••»
Pump Small k Leakage
iL Switched On A Leakage Peak j\ Peak
End
L±!
Gas
Concentration
Figure 4-9
Schematic of Product-Soluble Device12
-------
Table 4-3
Detection Specificities of Various Leak Monitoring Techniques
Type of Detects
Detector Gas
Intermittent Liquid-Phase
Grab Samplers No
Chemical- No
Sensitive Paste
Continuous Liquid-Phase
Interface Probe No
Product Soluble Yes
Devices
Electrical Yes
Resistivity Sensors
Thermal Con- No
ductivity Devices
Intermittent Gas-Phase
Detector Tubes Yes
Combustible Yes
Gas Detectors
PID's Yes
Portable GC's Yes
FID's Yes
Infrared Yes
Continuous Gas-Phase
Catalytic Sensor Yes
Devices
Metal Oxide Semi- Yes
Conductors
Product Yes
Permeable Devices
Diffusion Senors Yes
Detects
Liquid
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No
Yes
Type of
Compound
Detected
Immiscible
Liquids
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Variety of Gases
Hydrocarbons
Aromatics
Hydrocarbons
Aliphatics
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Detection
Adjustable
for
Specific
Compounds
No
No
No
Yes
No
No
Yes
No
No
Yes
No
Yes
No
No
No
Yes
aFalse positives that are due to background contamination from spills, etc.,
Potential
Interferents
None
None
None
Background HC's
UV Light
Background HC's
UV Light
ICE, H2S
None
Pb,H2O,O2,S
CO2,CH4,CI,etc.
Water Vapor
S cmpds.
None
Methane
Variable
Pb,H2O,O2,S
CO2,CH4,CI,etc.
CH4,H2O,CO,S
CH4,H20,S,
Background HC's
Gas
Displacement
False
Positives
or
Negatives3
Unlikely
Unlikely
No
N/A
No
Both
None
Both
Positives
No
Positives
Positives
Both
Both
Both
None
Severity
Interferents
N/A
N/A
N/A
Variable
Variable
Variable
Low
Potentially
High
Application
Dependent
N/A
Variable
Variable
Variable
Normally
Low
Variable
Unlikely
are possible with any of the detectors.
4-14
-------
Type of
Detector
Table 4-4
Detection Capabilities of Various Leak I
Detection Limit # of Sense
Lower Adjustable Upper Box
Monitoring Techn
rs
On-Line
Time
iques
Service Life
Control Box
Sensors
Intermittent Liquid-Phase
Grab Samplers
Chemical-
Sensitive Paste
1/32 in. No None N/A
1/64 in. No None N/A
N/A
N/A
N/A
N/A
Indefinite
N/A
Continuous Liquid-Phase
Interface Probe
Product Soluble
Devices
Electrical
Resistivity
Sensors
Thermal
Conductivity
Devices
1/8 in. No None 1-4
1/32 in. Yes None 4-15
1/32 in. Yes N/A 1
1/8 in. Yes N/A 10-15
Continuous
Continuous
Continuous
Continuous
>3 yrs.
>10yrs.
Indefinite
>3 yrs.
>5 yrs.
Til Leak
Detected
Indefinite
>2 yrs.
Intermittent Gas-Phase
Detector Tubes
Combustible
Gas Detectors
PID's
Portable GC's
FID'S
Infrared
0.5 ppm Yes 2000 ppm N/A
1500ppm No 100%LEL 1
0.1 ppm Yes 20,000 ppm 1-32
5 ppb Yes 2000 ppm 1
5 ppm No 1 0% 1
5 ppm Yes 100% 1
N/A
Continuous
N/A
N/A
N/A
N/A
N/A
10yr.
5-1 Oyr.
5-1 Oyr.
5-1 Oyr.
5-1 Oyr.
N/A
1yr.
2yr.
2yr.
Indefinite
Indefinite
Continuous Gas-Phase
Catalytic
Sensor
Devices
Metal Oxide
Semi-
conductors
Product
Permeable
Devices
Diffusion
Sensors
50 ppm No 100%LEL 1-8
10 ppm Yes 1% 1-32
10 ppm Yes 1% 1
100 ppm Yes 100% 4-16
Continuous
Continuous
Continuous
Continuous
lOyr.
10yr.
10yr.
10 yr.
>1 yr.
Syr.
Syr.
10yr.
4-15
-------
Table 4-4
Detection Capabilities of Various Leak Monitoring Techniques (continued)
Type of
Detector
Response
Time
Intermittent Liquid-Phase
Grab Samplers N/A
Chemical- <1 sec.
Lag
Time
N/A
N/A
Rise
Time
N/A
N/A
Fall
Time
N/A
N/A
Drift
N/A
N/A
Noise
N/A
N/A
Precision
N/A
N/A
Sensitive Paste
Continuous Liquid-Phase
Interface Probe sec.-30 min.
<20 min.
Product
Devices
Electrical
Resistivity
Sensors
Thermal
Conductivity
Devices
1-10hr.
sec.
intermittent Gas-Phase
Detector Tubes <1 min.
Not Known
Combustible
Gas Detectors
PID's
3 sec.
Portable GC's Variable
FID's 10 sec.
Infrared 30 sec.
Continuous Gas-Phase
Catalytic 20 sec.
Sensor Devices
Metal Oxide
Semi-
conductors
Product
Permeable
Devices
Diffusion
Sensors
<30 sec.
<10 min.
1 -5 sec.
Not Known Not Known Not Known Not Known Not Known Not Known
<20 min. <1 min. N/A N/A N/A Not Known
MOhr. <1 min. N/A N/A N/A Not Known
1-5 sec. <1 sec. <1 sec. N/A N/A Not Known
Negl. <1 min. N/A N/A Not Known Not Known
Not Known Not Known Not Known Not Known Not Known Not Known
<1 sec.
N/A
<1 sec.
<1 sec.
3 sec.
N/A
10 sec.
30 sec.
5-1 0 sec.
N/A
10-1 5 sec.
30 sec.
<1%of <1%of
Full Scale Full Scale
10%
<1%of <1%of 5-10%
Full Scale Full Scale
Negl.
Negl.
2%/day <1%of
Full Scale Full Scale
10%
<1%of
1%of 5%
Full Scale Full Scale
2-3 sec. 17 sec. 20 sec. 2% of
3-10 sec. 20 sec. 30-60 sec. Not Known Negl. 1-10%
<10min. 20 sec. 30-60 sec. Not Known Not Known Not Known
<1-5sec. <1-5sec. 15sec-min. Negl.
Negl.
Not Known
4-16
-------
Table 4-5
Experience of Various Leak Monitoring Techniques
Product Years
On On
Detector Market Market
Intermittent Liquid-Phase
Grab Yes Many
Samplers
Chemical- Yes Many
Sensitive
Paste
Continuous Liquid-Phase
Interface Yes 0.5
Probe
(cont. monitor)
Product Yes <1
Soluble
Devices
Electrical Yes 15
Resistivity
Sensors
Thermal Yes 1 0
Conductivity
Devices
Intermittent Gas-Phase
Detector Yes Not
Tubes Known
Combustible Yes Not
Gas Detectors Known
PID's Yes 2-10
Portable Yes 1-10
GC's
FID's Yes >5
Infrared Yes 10
Number
in
Service
1 ,000's
1 ,000's
12
>200
>500
1,000's
1,000's
Not
Known
>4.000
1,000's
Not
Known
100's
Has Leak
Been
Found?
Yes
Yes
No
Yes
Yes
Yes-
Many
Not
Known
Not
Known
Yes
Yes
Yes
Yes
Operating
Experience
Cheap &
Simple
Cheap &
Simple
Limited
Data
Not
Known
Not
Known
Used by
Some Major
Oils
Cheap and
Simple
Not
Known
Widely Used
as Portable
Instr.
Need Exper.
Operator
Widely Used
as Portable
Instr.
Not
Known
Maintenance
Problems
Minimal
Error
Minimal
Error
None
Ice
Minimal
Ice, Algae,
Hung-up
Float
Minimal
Poisoned
Catalyst
Calibration
Columns
Calibration
Not
Known
Cause
of False
Negatives
Operator
Operator
Break in
Cable
N/A
None
Elec. Short
Unlikely
Low
Sensitivity
Water
Vapor
Unlikely
Unlikely
N/A
Cause
of False
Positives
N/A
N/A
N/A
Bkgrnd. HC's
Polymer
Degrad.
Bkgrnd. HC's
Polymer
Degrad.
Fouled or
Hung-up
Probe
Gas Inter-
ferents
Not
Known
Gas Inter-
ferents
Unlikely
Methane
Gas Inter-
ferents
4-17
-------
Table 4-5
Experience of Various Leak Monitoring Techniques (continued)
Detector
Product Years Number Has Leak Cause Cause
On On in Been Operating Maintenance of False of False
Market Market Service Found? Experience Problems Negatives Positives
Continuous Gas-Phase
Catalytic Yes
Sensor
Devices
Metal Oxide Yes
Semi-
conductors
Product Yes
Permeable
Devices
Diffusion Yes
Sensors
1-15 >70,000 Yes
0-12 >1,300 Yes
Yes
1.5-20 >75,000 Yes
Used by Poisoned
Some Major Catalyst
Oils
Not
Known
Not
Known
Not
Known
Minimal
Water Vapor Unlikely
Elec. Short
Limited Use Pump Burn- Sensor N/A
Out Break
Good
Minimal
None
Elec. Short
4-18
-------
Table 4-6
Costs For Various Leak Monitoring Techniques
Capital Costs ($)
Type of Control
Detector Box
Intermittent Liquid-Phase
Grab Samplers N/A
Chemical- N/A
Sensitive Paste
Continuous Liquid-Phase
Interface Probe 1 ,200
(cont. monitor)
Product 400-1,200
Soluble Devices
Electrical 1 ,500
Resistivity
Sensors
Thermal 1,400
Conductivity
Devices
Intermittent Gas-Phase
Detector Tubes N/A
Combustible Not
Gas Detectors Known
PID's 3,900-6,300
Portable GC's 5,800-14,000
FID'S 5,000
Infrared 1,750-9,000
Continuous Gas-Phase
Catalytic 700-2,400
Sensor Devices (avg=1 ,000)
Metal Oxide 500-4,000
Semi- (avg=1 ,000)
Conductors
Product 5,000
Permeable
Devices
Diffusion 1 ,400-4,200
Sensors
Sensor
<100
<10
200
200-900
100-200
600-700
<100
Not
Known
200-1,700
N/A
N/A
N/A
65-200
28-1,500
(avg=100)
6/ft.
200-300
New
Facility
N/A
N/A
Not
Known
1,500-
11,000
2,800
2,500
N/A
Not
Known
N/A
N/A
N/A
1,750-
30,000
Not
Known
Not
Known
Not
Known
5,000
Installation Costs ($) (4 Tanks)
Old
Facility
N/A
N/A
Not
Known
3,000-
1 1 ,000
5,500
5,500
N/A
Not
Known
N/A
N/A
N/A
1,750-
30,000
Not
Known
Not
Known
Not
Known
7,000
Old Wei!
N/A
N/A
Not
Known
1 ,500-
7,000
3,300
4,200
N/A
Not
Known
N/A
N/A
N/A
Not
Known
Not
Known
Not
Known
Not
Known
5,000
Maintenance
Costs-$
Nil
Nil
Minimal
Minimal
Minimal
600/yr.
Nil
Not
Known
N/A
N/A
N/A
Variable
Minimal
Minimal
Minimal
0-1 ,800/yr.
Labor
Costs-$
High
Medium
Low
Low
Low
Low
Medium
Low
Medium
High
Medium
Medium
Low
Low
Low
Low
4-19
-------
Table 4-7
Recomended Procedures for Various Leak Monitoring Techniques
Can
Type of Are Wells System Be Recommend Utility Location
Detector Required? Retrofitted? Site Study Service to Tank
intermittent Liquid-Phase
Grab Samplers Yes
Chemical- Yes
Sensitive Paste
Continous Liquid-Phase
Interface Probe Yes
(cont. monitor)
Product Soluble Usually
Devices
Electrical Resist- Yes
ivity Sensors
Thermal Yes
Conductivity
Devices
Intermittent Gas-Phase
Detector Tubes Usually
Combustible Usually
Gas Detectors
PIDs Usually
Portable GCs Usually
FIDs Usually
Infrared Usually
Continuous Gas-Phase
Catalytic Sensor Usually
Devices
Metal-Oxide Usually
Semiconductors
Product No
Permeable
Devices
Diffusion Usually
Sensors
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
None
None
None
None or Elec.
AC Line
AC Line
None
AC Line
None or Elec.
None or Elec.
None
None or Elec.
None or Elec.
None or Elec.
AC Line
AC Line
Downgradient
Downgradient
Downgradient
Depends on
# of Sensors
In Excavation
Below Tank
Downgradient
Downgradient
Downgradient
Downgradient
Downgradient
Downgradient
Variable
In Excavation
In Excavation
Under Tank
Bottom
Distance
From Tank
In Excavation
In Excavation
On Perimeter
of Excavation
Variable
2ft.
2ft.
Bottom
In Excavation
In Excavation
In Excavation
In Excavation
In Excavation
In Excavation
Variable
1ft.
Not Known
Close
Proximity
\
4-20
-------
Table 4-7
Recommended Procedures for Various Leak Monitoring Techniques (Continued)
Number Adjustable
Type of of Sensors Calibration Instrument Use in Operating Temp.
Detector Per Tank Procedures Settings Wet Soil Environment Range
Voltage
Range
Intermittent Liquid-Phase
Grab Samplers
Chemical-
Sensitive Paste
N/A N/A
N/A N/A
N/A
N/A
Yes
Yes
N/A
N/A
>0°C
N/A
N/A
N/A
Continuous Liquid-Phase
Interface Probe
(cont. monitor)
Product
Soluble Devices
Electrical Resis-
tivity Sensors
Thermal
Conductivity
Devices
1 -4 None
1-4 None
4 None
4 None
None
None
None
None
Yes
Yes
Yes
Yes
Any
Any
Any
Any
-45-60°C
0-50°C
0-120°C
-40-50°C
N/A
85-1 35V
..
100-1 40V
Intermittent Gas-Phase
Detector Tubes
Combustible
Gas Detectors
PIDs
Portable GCs
FIDs
Infrared
N/A Cal. Gas
Not Not
Known Known
1-6 Cal. Gas
1 or More Cal. Gas
Not Known Cal. Gas
Not Known Cal. Gas
Yes
Not
Known
Several
Several
None
Zero/Span
Yes
Not
Known
Yes
Yes
Yes
Yes
N/A
Not
Known
Any
Non-
Explosive
Any
Any
N/A
Not
Known
0-50°C
0-50°C
0-60°C
0-40°C
N/A
Not
Known
11 0-1 20V
110-1 15V
N/A
11 0-1 30V
Continuous Gas-Phase
Catalytic Sensor
Devices
Metal-Oxide
Semiconductors
Variable Cal. Gas
1-2 Cal. Gas
Product 2 Cal. Gas
Permeable Devices
Diffusion
Sensors
1 or More Cal. Gas
None-
Several
None-
Several
Gain/Zero
Several
Yes
Yes
Yes
Yes
Any
Non-
Explosive
Any
Air
-20-50°C
-10->60°C
Not
Known
-75-70°C
105-1 30V
105-1 25V
Not
Known
105-1 25V
4-21
-------
Table 4-7
Recommended Procedures for Various Leak Monitoring Techniques (Continued)
Type of
Detector
Maint.
Require.
Maint.
Schedule
Calibration
Procedures
Calibration
Schedule
Flow Rate
Certifi-
cation
Surface
Vs. Under-
ground
Intermittent Liquid-Phase
Grab Samplers
Chemical-
Sensitive Paste
Cleaning
Cleaning
Before Use
Before Use
N/A
N/A
N/A
N/A
N/A
N/A
No
No
No
No
Continuous Liquid-Phase
Interface Probe
(cont. monitor)
Product
Soluble Devices
Electrical Resis-
tivity Sensors
Thermal
Conductivity
Devices
Inspect
System
Inspect
System
Inspect
System
Inspect
System
Once every
2yrs
2/yr.
Not Known
6/yr.
None
None
None
None
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
No
Yes
Yes
Yes
No
e
No
No
No
Intermittent Gas-Phase
Detector Tubes
Combustible
Gas Detectors
PIDs
Portable GCs
FIDs
Infrared
None
Inspect
System
Clean Lamp
Columns
Replace Fuel
Various
N/A
Not Known
As Needed
2/yr.
As Needed
Monthly
Std. Gas
Not Known
Zero/Span
Gas Stds.
Zero/Span
Gas Stds.
Continuous Gas-Phase
Catalytic Sensor
Devices
Metal-Oxide
Semiconductors
Product
Permeable
Devices
Diffusion
Sensors
Periodic
Calibration
Inspect
System
Not Known
Inspect
System
Variable
2/yr.
Not Known
4/yr.
Std. Gas
Std. Gas
Not Known
Electronic
As
Required
Not Known
Daily
Daily
Daily
Daily-
Monthly
Variable
Variable
Not Known
At Install.
Not Known
Not Known
0.05-0.6 L/min.
0.01 L/min.
Not Known
0.5-1. SL/mln.
0.5-1 L/min.
2 L/min.
0.7-1.1 L/min.
N/A
No
Not Known
Std. Gases
Std. Gases
Std. Gases
Std. Gases
Cert. Gas
Cal-Kits
Not Known
Not Known
No
No
No
No
No
No
No
No
No
No
4-22
-------
products with similar performance characteristics.
This grouping will make It easier to determine the
number of sets of performance specifications and
certification procedures that need to be developed in
subsequent phases of this project.
Analysis of vendor responses revealed that the leak
monitoring techniques fall into four relatively obvious
categories, illustrated in Figure 4-10. Several factors,
such as regulatory constraints and type of facility (old
versus new), proved to be unimportant at this time in
categorizing the techniques; this is contrary to initial
expectations. There is some overlap between the
categories. For instance, the product-soluble devices
will react with vapor as well as liquid, though at a
much slower rate.
4.3.2 Site-Specific Factors
Table 4-8 summarizes the effect of site-specific factors
on the selection of a leak monitoring system. In
general, the most important parameters affecting leak
monitoring systems are secondary containment and
groundwater depth. If secondary containment is used,
the leak monitoring system can be simpler, and
continuous monitoring is less important. Deep
groundwater favors gas-phase detection methods,
whereas shallow groundwater favors liquid-phase
detection methods.
4.4 Discussion of Results
This discussion of the questionnaire sections ranges
from general to specific comments.
4.4.1 Overall Results
As discussed earlier, the leak monitoring techniques
fall into four categories:
o Intermittent liquid-phase detection;
o Intermittent gas-phase detection;
o Continuous liquid-phase detection; and
o Continuous gas-phase detection.
The techniques within a category tended to have
similar capabilities and deficiencies. The relative
advantages and disadvantages of each technique are
summarized in Table 4-9. In general, the intermittent
gas- and liquid-phase monitoring techniques are not
only more labor intensive but also more reliable than
the automated, continuous gas- and liquid-phase
monitoring techniques. Gas detection is more
sensitive than liquid detection, but the equipment is
more complex and expensive and is more susceptible
to interferences.
The survey response was better than expected in
terms of the number of vendors returning completed
All Leak Monitoring Techniques
O
Automated/Frequent
Sampling
Manual/Periodic
Sampling
Continuous Monitoring Technique
Intermittent Monitoring Technique
High
Low
High
Low
Continuous,
Gas-Phase
Monitoring
Technique
Continuous,
Liquid-Phase
Monitoring
Technique
Intermittent,
Gas-Phase
Monitoring
Technique
Intermittent,
Liquid-Phase
Monitoring
Technique
1 Labor Requirements/Monitoring Duration
2 Sensitivity/Equipment Complexity
Figure 4-10
Decision Tree for Detector Classification
4-23
-------
Table 4-8
Effect of Site-Specific Factors and Design Options on
Selection of Leak Detection Methods
Variable
Options
Effect of Option on Leak Detection
System Age
Tank Type
Secondary
Containment
Overfill
Protection
Groundwater
Depth
Excavation Type
Environmental
Considerations
New installation
Existing installation
Steel
Fiberglass
Coated steel
Double-walled tank
Natural or synthetic liner
Concrete vault
Yes
No
Deep
Shallow
Highly variable
Wet
Dry
Environmentally-sensitive
area or very hazardous
product
None.
May be difficult to retrofit leak detection
capability.
None.
None.
None.
Monitor interstitial space.
Place leak detection equipment within
liner. Continuous monitoring not normally
necessary.
Place leak detection equipment within
vault. Continuous monitoring not normally
necessary.
None.
Vapor monitors may be unsuitable if
frequent spills result in high background
vapor concentrations.
Use U-tube type collection sump for new
installations.
Use one or more observation wells per
excavation. Continuous monitoring
recommended.
Floating detectors may be unsuitable.
Liquid-sensing detectors preferable to
vapor-sensing detectors.
Vapor-sensing detectors preferable to
liquid-sensing detectors.
Continuous, vapor-sensing detectors
recommended.
4-24
-------
Table 4-9
Relative Advantages/Disadvantages of Leak Monitoring Techniques
Monitoring
Category3/ Technique
Advantages
Disadvantages
1 Simple, quick, and accurate
2 Inexpensive equipment
Intermittent Liquid-Phase
Chemical-sensitive paste
Intermittent Gas-Phase
Combustible Gas detector 1 Inexpensive gas-phase
analyzer
Detector tube
1 Inexpensive equipment
Flame-ionization detector, 1 Quick, accurate, and very
Portable gas chromotograph, sensitive
Infrared detector, and
Photoionization detector
1 Does not provide continuous monitoring
2 Labor-intensive
3 Provides only limited information
regarding nature of contamination
1 Insensitive gas-phase technique
2 Catalyst is subject to poisoning
3 Does not provide continuous monitoring
4 Labor-intensive
1 Does not provide continuous monitoring
2 Labor-intensive
1 Do not provide continuous monitoring
2 Labor-intensive
3 Expensive equipment
4 Experienced operator required
5 Not well suited for contaminated areas
or areas with high background
concentrations
Continuous Liquid-Phase
Interface probe
1 Medium cost
1 Subject to biofouling
Product soluble device
Thermal conductivity
Continuous Gas-Phase
Catalytic sensor, Diffusion
sensor, and Metal-oxide
semiconductor
Product permeable device
1 Inexpensive equipment
2 Simple method
3 Detects vapor as well as
liquid
1 Widely used method
2 Medium cost
1 Quick, accurate, and very
sensitive
1 Can determine magnitude
and location of leak
1 Need to replace sensors every 6 months
2 Device may degrade because of back-
ground contamination, abrasion, or UV light
1 Subject to biofouling
2 Float mechanism may fail because
of ice or physical obstruction
1 Expensive equipment
2 Not suitable for contaminated areas or
areas with high backgound concentrations
3 Catalytic sensor subject to catalyst poisoning
1 Expensive equipment
2 Little user experience to date
3 Not suitable for contaminated areas or
areas with high background concentrations
4 Water may cause false alarm
aTypical use of technique
4-25
-------
questionnaires; however, In some cases, the quality of
the responses was not acceptable. Vendors were
particularly reluctant to discuss (or lacked data on)
maintenance problems and false positive or negative
readings. Also, in some cases, the description of
typical installed costs appeared inadequate.
4.4.2 Questionnaire Results
Principle of Operation. Many vendors were unclear
regarding the exact principle of operation utilized by
their product. Vendor literature was necessarily used
to augment the questionnaire responses.
Detection Specificity. The majority of sensors respond
to vapor or liquid; only diffusion sensors and product-
permeable devices respond to both. All the
techniques respond to most hydrocarbons or
commonly stored petroleum products. The sensors
cannot be adjusted to be specific for a given product
(except for gas chromatographs). However, some
sensors can be adjusted to increase their specificity to
a class of compounds. For example, the dissolvable
component of product-soluble devices and electric
resistivity sensors can be of variable thickness to vary
the sensitivity. Similarly, many gas-phase detectors
can be adjusted to increase their sensitivity to one
class of compounds over another. A number of
potential interferents were identified, and these appear
to be the major cause of false positive and false
negative results. In general, the impact of
interferences on leak detectors is not a major problem.
Detection Capability. As expected, gas-phase
detection is much more sensitive than liquid-phase
detection. The response time of all techniques Is less
than 1 minute except for the product-soluble and
product-permeable sensors which respond in less
than 20 minutes. Drift, noise, precision, and
applicable test procedure information was very limited.
The majority of the continuous techniques permit
multiple sensors to operate from a single control box.
Finally, the estimated service life averaged 10 years
for control boxes and about 2 years for sensors.
Experience. Thermal conductivity devices, grab
samplers, and chemical-sensitive pastes are the only
techniques that have been widely used for monitoring
underground storage tanks. The other techniques
either are new to the market or have been used in
other applications. Vendor responses regarding years
on the market and the number of devices in service
are not limited to use of the devices for UST
applications. Information regarding operating
experience, maintenance problems, false negative
readings, false positive readings, and
repair/replacement experience was generally limited.
Cost. Costs for control box and sensors ranged from
less than $100 to $14,000. Gas-phase detection
systems averaged about $4,000 versus $1,500 for
liquid-phase detection systems. Installation costs may
be as much as $30,000, but there were limited
responses to this question. Most vendors thought
maintenance costs were minimal.
Recommended Procedures. In general, the various
leak monitoring systems require observation wells,
can be retrofitted, can operate under any soil
conditions, should be located within the tank
excavation, and cannot differentiate between spills
and leaks. Again, it should be emphasized that these
conclusions are based only on the data provided by
the manufacturers. They gave only limited answers to
maintenance, calibration, and certification questions.
For calibration, the vendors typically responded either
that none was required or that some unspecified
calibration gas or gasoline was needed. Bacharach
Instruments markets a calibration kit for their sensors.
The general response to the question on certification
was to use an unspecified gas standard. However,
detailed certification procedures were given for two of
the leak monitoring devices: the electrical resistivity
sensor produced by Total Containment and the
Adsistor sensor marketed by several vendors. In
addition, Rexnord states that their catalytic sensor
device can be certified by "FM #6310-6330 procedure
and CSA #C22.2 No. 152 procedure." Additional
testing procedure information had been solicited from
vendors and testing concerns. Information collected
to date is summarized in Table 4-10 and will be used
in designing test procedures during future work.
Vendors typically stated that their devices cannot
distinguish between surface spills and leaks.
However, over time, all the leak monitoring devices
may be able to do so. Presumably, a surface spill will
result in a "front" of contamination moving through the
soil with concentrations decreasing over time. Those
devices that give a quantitative readout should show a
drop in concentration over time for a spill but not for a
leak. Devices that give a binary readout (alarm or
non-alarm) can be reset or can have the sensing
element replaced and eventually can distinguish
between spills and leaks.
4-26
-------
Table 4-10
Available Test Procedures and Results for Leak Monitors
Summary of
Testing Agency/
Vendor
Test Information
In-house testing procedures and designs
(information not yet received).
Testing Agency
Testing Agency
1. Active Leak Testing
Report for Adsistor ® (1970). Tests consisted of:
2. National Swedish
Institute for Materials
Testing
Boundary value for gasoline
3. B.C. Research
4. Bacharach
5. C.S.A.
6. Fire Marshall,
Campbell, CA
7. EMMCO
8. Geneico
Testing Agency
Vendor
Testing Agency
Inspection Agency
Vendor/R&D
Vendor
9. Factory Mutual
(P.M.)
Testing Agency
10. In-Situ
Vendor
Relative humidity
3 Consumption
4 Tension
5 Temperature
6 Reaction time
Shock
8 Brine water
9 Self-sureness
10 Installation.
No additional testing data.
References were sent for further contacts.
P.M. and C.S.A. are contracted to test their detectors.
Contacts for both and P.M. reports were received.3
Test procedures pertaining to gasoline vapor
detectors (not yet received).
Monitoring standards for Santa Clara and
inspection checklist were received.
Sensor operations information.
Soil cell designs, vapor sensor testing consisting of:
1 Frequency
2 Location
3 Calibration
4 Installation
5 Site Evaluation.
Approval standards for combustible gas detectors.
Discussed are the following:
1 Detector construction
2 Marketing (labeling)
3 Tests performed
4 Apparatus and test procedures
In-house testing procedures and specifications
along with draft test results. Testing considered
response time for liquid and vapor detection.
11. Pollulert Systems
12. Universal Sensors
and Devices, Inc.
Vendor
Vendor
In-house lab and field test results.
Soil cell tests for measuring diffusion rate.
aF.M. reports are proprietary information
4-27
-------
-------
SECTION 5
References
1. Jeyapalan, J. K., and J.B. Hutchison.
Underground Storage Tanks-Leak Prevention,
Leak Detection, and Design.
2. Hazardous Waste Report-Trends & Analyses.
The Next Regulatory Battle: Leaking
Underground Storage Tanks, May 1984.
3. Predpall, D. F., W. Rogers, and A. Lament. An
Underground Tank Spill Prevention Program. In:
Proceedings of Petroleum Hydrocarbons and
Organic Chemicals in Ground Water, Houston,
Texas, November 1984. pp. 17-32.
4. Marketer's Report of the Texas Oil Marketers
Association. Why Be Concerned about
Underground Storage Tanks? June 1985.
5. The Hazardous and Solid Waste Amendments of
1984 to the Resource Conservation and Recovery
Act, Subtitle 1, Sections 9001-9010 of U.S. Public
Law 98-616, November 1984.
6. Scheinfeld, R. A., and T. G. Schwendeman. The
Monitoring of Underground Storage Tanks--
Current Technology. In: Proceedings of
Petroleum Hydrocarbons and Organic Chemicals
in Ground Water, Houston, Texas, November
1985.
7. Eklund, B. Evaluation of Methods for Leak
Detection in Underground Storage Tanks and
Connected Piping. In: Proceedings of the Air
Pollution Control Association's 79th Annual
Meeting and Exhibition, Minneapolis, Minnesota,
June 1986.
8. Horiba Engineering IR Hydrocarbon Gas Analyzer
Product Literature.
9. HNU Model P1101 Product Literature.
10. Pollulert Systems FD102 Thermal Conductivity
Sensor Product Literature.
11. Teledyne Geotech LASP System Product
Literature.
5-1
-------
-------
SECTION 6
Bibliography
This section contains a selected bibliography of general references and a listing
of other pertinent citations from the literature search.
6.1 Selected Bibliography
Leak Monitoring
American Petroleum Institute. Observation Wells as
Leak Monitoring Techniques. Unpublished Draft
Report, Washington, D.C. 1986.
Donaghey, L. F. Groundwater Protection through
Early Detection of Hydrocarbon Leaks. In:
Proceedings of Oil Spill Prevention, Behavior,
Control, and Cleanup Conference, Los Angeles,
California, February 1985, Washington, D.C.,
American Petroleum Institute, pp. 263-65.
Eklund, A. G., and B. M. Eklund. Integrity Test and
Leak Detection for Underground Storage Tanks.
Edison Electric Institute. 1986.
Eklund, B. Evaluation of Methods for Leak Detection in
Underground Storage Tanks and Connected
Piping. In: Proceedings of the Air Pollution
Control Association's 79th Annual Meeting and
Exhibition, Minneapolis, Minnesota. June 1986.
Lu, J., and W. Barcikowski. Cost-Effectiveness
Evaluation of Leak Detection and Monitoring
Technologies for Leaking Underground Storage
Tanks. In: Proceedings of the National
Conference on Hazardous Wastes and Hazardous
Materials, Atlanta, Georgia. March 1986.
Petroleum Equipment Institute. 1986 Petroleum
Equipment Directory. PEL 1986.
Scheinfeld, R. A., J. B. Robertson, and T. G.
Schwendeman. Underground Storage Tank
Monitoring: Observation Well Based Systems.
Ground Water Monitoring Review. Fall 1986.
The New York State Department of Environmental
Conservation. Technology for the Storage of
Hazardous Liquids. March 1985.
van Ee, J. J. New Approaches to the Evaluation of
Leak Detection Monitors for Underground Storage
Tanks. In: Proceedings of the API/NWWA
Petroleum Hydrocarbons and Organic Chemicals
in Ground Water Conference, Houston, Texas.
November 1986.
Related Topics: Design, Installation, Operations,
Regulations, and Integrity Testing
American Petroleum Institute. Installation of
Underground Petroleum Storage Systems. API
Publication 1615. November 1979.
American Petroleum Institute. Recommended Practice
for Bulk Liquid Stock Control at Retail Outlets. API
Publication Number 1621. 1977.
American Petroleum Institute. Recommended
Practice for Underground Petroleum Product
Storage Systems at Marketing and Distribution
Facilities. API Publication Number 1635.
December 1984.
Anonymous. EPA to Examine Tank Leak Tests;
Defines Many Causes of "Noise." Petroleum
Marketer. September-October 1985.
Buonocore, A. 0., G. F. Kotas, and K. G. Garrahan.
New Requirements for Underground Storage
Tanks. In: Proceedings of the National
Conference on Hazardous Wastes and Hazardous
Materials, Atlanta, Georgia. March 1986. pp. 246-
250.
Curran, S. D. Prevention and Detection of Leaks from
Underground Gasoline Storage Systems. In:
Proceedings of 6th National Ground-Water Quality
Symposium, Atlanta, Georgia, September 1982.
National Water Well Association, Worthington,
Ohio. 1983. pp. 93-100.
Heckard, M. States Crack Down on Fuel Tank Regs.
Fleet Owner, Small Fleet Edition. March 1985.
Radian Corporation. State-of-the-Art Tank and Piping
Technology and Installation Practices. Edison
Electric Institute. 1986.
6-1
-------
National Fire Protection Association, Inc. Underground
Leakage of Flammable and Combustible Liquids.
NFPA Document No. 329. June 1983.
New York State Department of Environmental
Conservation. Recommended Practices for
Underground Liquid Storage Systems. 1985.
New York State Department of Environmental
Conservation. Technology for the Storage of
Hazardous Liquids. March 1985.
Niaki, S., and J. A. Broscious. Underground Tank
Leak Detection Methods: A State-of-the-Art
Review. EPA Contract No. 68-02-3069,
EPA/HWERL-Cin. In Press.
PACE. Underground Tank Systems: Review of State
of the Art and Guidelines. PACE Report No. 82-3.
PACE. Proceedings of Underground Tank Testing
Symposium, Toronto, Ontario, May 1982.
Petroleum Association for Conservation of the
Canadian Environment.
Petroleum Equipment Institute. Recommended
Practices for Installation of Underground Liquid
Storage Systems. 1985.
Tusa, W. Underground Leaks: True Corporate Costs.
Pollution Engineering. February 1986.
U. S. Environmental Protection Agency. More About
Leaking Underground Storage Tanks: A
Background Booklet for the Chemical Advisory.
EPA Office of Toxic Substances, Washington,
D.C. October 1984.
Wilcox, H. K., J. D. Flora, C. L. Haile, M. J. Gabriel,
and J. W. Maresca. Development of a Tank Test
Method for a National Survey of Underground
Storage Tanks. EPA-560/5-86-014, U. S.
Environmental Protection Agency. May 1986.
Woods, P. H., and D. E. Webster. Underground
Storage Tanks: Problems, Technology, and
Trends, Pollution Engineering 16(7):30-40,1984.
6.2 Additional Citations Identified in
Literature Search
Adamowski, S. J., A. J. Caracciolo III, and G. D.
Knowles. Underground Storage System
Assessment, Testing, and Remediation. In:
Proceedings of the National Conference on
Hazardous Wastes and Hazardous Materials,
Atlanta, Georgia. March 1986. pp. 269-272.
Adams, T. E. Hydrocarbon Leakage Detection
System and Apparatus. Canadian Patent No.
1,185,693. October 28,1985.
Ainlay, J. A. Leak Detector for Underground Storage
Tanks. U. S. Patent No. 4,474,054. October 2,
1984.
American Petroleum Institute. Cathodic Protection of
Underground Petroleum Storage Tanks and
Piping Systems. API Publication 1632. 1983.
American Petroleum Institute. Recommended
Practice for Abandonment or Removal of Used
Underground Service Station Tanks. API
Publication 1604, March 1981.
American Petroleum Institute. Recommended
Practice for the Interior Lining of Existing
Underground Storage Tanks. API Publication
1631. 1983.
American Petroleum Institute. Tank and Piping Leak
Survey. February 1981.
American Petroleum Institute. Underground Spill
Cleanup Manual. API Publication 1628. June
1980.
Anonymous. API, EPA Study Hydrocarbon Detection
for Underground Tank Monitoring Wells.
Petroleum Marketer. May-June 1986. pp. 10-18.
Anonymous. A Problem that Won't Go Away. National
Petroleum News. September 1985. pp. 31-35.
Anonymous. Choosing a Compatible Underground
Storage Tank. The Hazardous Waste Consultant.
September-October 1986. pp. 1-14 to 1-17.
Anonymous. Data on Leaking Underground Storage
Tanks Presented in EPA Study. The Hazardous
Waste Consultant. November-December 1986.
pp. 2-22 to 2-25.
Anonymous. Florida Finalizes Rules Regarding Tank
Leaks, Is Second State to Act. National Petroleum
News. June 1984. p.63.
' Anonymous. How Hazardous Waste Tanks Fail. The
Hazardous Waste Consultant. July-August 1986.
pp. 1-6 to 109.
Anonymous. Petro-Tite Evolves to Find Leaking
Tanks. Petroleum Marketer. November-December
1985.
6-2
-------
Anonymous. Reliable On-Line Monitoring for Better
Effluent Control. Process Eng., 73:74-75, May
1980.
Anonymous. Small Jobbers Endangered, Study
Predicts; Tank Leak Mess Already is Wounding
Some. National Petroleum News. March 1984.
Anonymous. Sohio Keeps Watch on Underground
Tanks. Ground Water Monitoring Review. Winter
1986. p.14.
Anonymous. System Detects Underground Leaks.
Oilweek 31 (51) :23-24, January 1981.
Anonymous. Tank Audit Computer Detects Leak
Rates. Petroleum Marketer. May-June 1986.
pp.41-43.
Anonymous. Underground Storage Tanks: Secondary
Containment Methods Described. The Hazardous
Waste Consultant. November-December, 1985.
pp. 1-28 to 1-31.
Askenaizer, D. J., W. Barcikowski, K. V. B. Jennings,
and J. E. Sarna. Development of a Compliance
Program for Underground Tanks Containing
Hazardous Substances. Report to Southern
California Edison Co., Contract No. 2742915.
March 1985.
B. C. Research. Report on Investigations and
Research to Develop a Service Station
Underground Tank Leak Detector. Petroleum
Association for Conservation of the Canadian
Environment (PACE), Report No. 81-3.
Bisque, R. E. Migration Rates of Volatiles from Buried
Hydrocarbon Sources through Soil Media. In:
Proceedings of the NWWA/API Petroleum
Hydrocarbons and Organic Chemicals in Ground
Water Conference, Houston, Texas. November
1984.
Blevins, M. L., and D. E. Williams. Management of
Gasoline Leaks—A Positive Outlook. In:
Innovative Means of Dealing with Potential
Sources of Ground Water Contamination;
Proceedings of the 7th National Ground Water
Quality Symposium, Las Vegas, Nevada,
September 1984. pp. 46-83. Published by NWWA,
Worthington, Ohio. 1985.
Cheremisinoff, P. N., J. G. Casana, and H. W.
Pritchard. Special Report: Update on Underground
Tanks. Pollution Engineering. August 1986.
Cheremisinoff, P. N., J. G. Casana, and R. P.
Ouellette. Special Report: Underground Storage
Tank Control. Pollution Engineering. February
1986.
Dowd, R. M. Leaking Underground Storage Tanks.
Environmental Science and Technology. 18(10),
1984.
Dragun, J., A. C.,Kuffner, and R. W. Schneiter.
Transport and Transformations of Organic
Chemicals. Chem. Eng., 91(24):65-72,1984.
Eklund, B. Detection of Hydrocarbons in Groundwater
by Analysis of Shallow Soil Gas/Vapor. API
Publication No. 4394. May 1985.
Everett, L. G., E. W. Hoylman, L. G. Wilson, and L. G.
McMillion. Constraints and Categories of Vadose
Zone Monitoring Devices. Ground Water
Monitoring Review 4(1):26-32, Winter 1984.
Fletcher, S. Leaks in Storage Tanks Polluting
Groundwater. Houston Post. December 1985.
Gerstenmaier, W. J., and J. A. Todd. Leak Detection
Systems and Method for Fluid Delivery Piping.
U.S. Patent No. 4,131,216. December 26,1978.
Guest, R. J. Leak Detector and Method. U.S. Patent
No. 3,691,819. September 19,1972.
Hazardous Waste Report-Trends & Analyses. The
Next Regulatory Battle: Leaking Underground
Storage Tanks. May 1984.
Hern, S. C., and S. M. Melancon. Vadose Zone
Modeling of Organic Pollutants. Lewis Publishers,
Inc. 1986.
Hoick, J. N., and T. P. Clark. Regulation of
Underground Storage Tanks in Minnesota. In:
Proceedings of the 79th Annual Meeting of the Air
Pollution Control Association. Minneapolis,
Minnesota. June 1986.
Horsley, S. W., and D. S. Blackmar. Development
and Implementation of Regulations to Control
Underground Fuel Storage Tanks on Cape Cod.
In: Proceedings of the 7th National Ground-Water
Quality Symposium, Las Vegas, Nevada,
September 1984. National Water Well
Association, Worthington, Ohio. 1985. pp. 29-39.
Hubbard, G. O. Locating Holes in Tubing. U. S.
Patent No. 3,696,660. October 10,1972.
6-3
-------
Huebler, J, E., and J, M. Craig. Sonic Detection of
Gas Leaks In Underground Pipes. U.S. Patent
No. 4,455,863. June 26,1984.
Jeyapalan, J. K., and J.B. Hutchison. Underground
Storage Tanks-Leak Prevention, Leak Detection,
and Design. In: Proceedings of the National
Conference on Hazardous Wastes and Hazardous
Materials, Atlanta, Georgia. March 1986.
Kahn, E. Proposal Gives Muscle to EPA on
Underground Tank Rules. Super Service Station.
April 1984.
Knopp, P. V. Underground Tank Management.
Pollution Engineering. December 1985. pp. 24-27.
Lund, T. Corrosion of Underground Storage Tanks.
Presented at HazPro '86, Baltimore, Maryland.
April 1986. Sponsored by Pollution Engineering.
Maresca Jr., J. W., P. C. Evans, R. A. Padden, and R.
E. Wanner. Measurement of Small Leaks in
Underground Gasoline Storage Tanks Using
Laser Interferometry. SRI international Project No.
7637. September 1981.
Marketer's Report of the Texas Oil Marketers
Association. Why Be Concerned about
Underground Storage Tanks? June 1985.
McLean, F. R. Leak Seeking in Underground Tanks.
Presented at the 43rd Annual Fire Department
Instructors Conference, Kansas City, Missouri.
March-April 1971.
Milanovich, F. P. Detecting Chloro-organics In
Groundwater. Environ. Sci. Technol. 20(5):41-42,
1986.
Milke, G. Method of and Apparatus for Locating Leak
Areas of Pipe Lines, Especially Underground Pipe
Lines. U. S. Patent No. 3,722,261.
Murphy Jr., F. W., and B. G. Sparks. Remote Multiple
Tank Liquid Level Measuring Device. U. S. Patent
No. 4,064,752. December 27,1977.
Nacht, S. H. Underground Storage Tank Compatibility.
Presented at HazPro '86, Baltimore, Maryland.
April 1986. Sponsored by Pollution Engineering.
National Fire Protection Association, Inc. Flammable
and Combustible Liquids Code. NFPA Publication
No. 30. 1984.
Petroleum Equipment Institute. Future Trends In
Petroleum Marketing Operations. PEI Manual
8342.
Plehn, S. W. An Introduction to LUST.
Environmental Forum. July 1984. pp. 5-9.
The
Predpall, D. F., W. Rogers, and A. Lamont. An
Underground Tank Spill Prevention Program. In:
Proceedings of Petroleum Hydrocarbons and
Organic Chemicals in Ground Water, Houston,
Texas. November 1984. pp. 17-32.
Robbins, G. A., and M. M. Gemmell. Factoring
Requiring Resolution in Installing Vadose Zone
Monitoring Systems. Ground Water Monitoring
Review. Summer 1985. pp. 75-80.
Robbins, R. J., and D. G. Nichols. Electric Leak
Detection Systems for Underground Stored
Chemicals and Fuels. In: Innovative Means of
Dealing with Potential Sources of Ground Water
Contamination; Proceedings of the 7th National
Ground Water Quality Symposium, Las Vegas,
Nevada, September 1984. pp. 40-44. Published
by NWWA, Worthington, Ohio. 1985.
Scheinfeld, R. A., and T. G. Schwendeman. The
Monitoring of Underground Storage Tanks-
Current Technology. In: Proceedings of
Petroleum Hydrocarbons and Organic Chemicals
in Ground Water, Houston, Texas. November
1985.
Shaner, J. R. Underground Tank Dilemma: New
Rules Could Cost Industry Billions. National
Petroleum News. August 1984. pp. 36-39.
Singh, P. N. Case Study of Product Detection in
Ground Water. In: Proceedings of the National
Conference on Hazardous Wastes and Hazardous
Materials, Atlanta, Georgia. March 1986. pp.
273-277.
Steel Tank Institute. Tank Talk. Bimonthly Newsletter
(various issues).
Sun, M. EPA Grapples with Regulating Underground
Storage Tanks. Science, 233:518.
Tabary, J. Underground Storage of Petroleum
Products. Pet. Rev. 27(318) :213-217, 1973.
The Hazardous and Solid Waste Amendments of 1984
to the Resource Conservation and Recovery Act
Subtitle 1, Sections 9001-9010 of U.S. Public Law
98-616. November 1984.
6-4
-------
Underwriters Laboratories, Inc. Glass-Fiber-
Reinforced Plastic Tanks for Underground Storage
of Petroleum Products. UL Publication No. 1316.
Underwriters Laboratories, Inc. Steel Underground
Tanks for Flammable and Combustible Liquids.
UL Publication No. 58.
Upton, H. Tulsa Letter. Petroleum Equipment
Institute Weekly Newsletter (various issues).
Utility Data Institute. Preliminary Characterization of
Underground Storage Tanks Utilized by Electric
Utilities., December 1984.
Witherow, W. E. Epichlorohydrin in Secondary
Containment Systems. In: Innovative Means of
Dealing with Potential Sources of Ground Water
Contamination; Proceedings of the 7th National
Ground Water Quality Symposium, Las Vegas,
Nevada, September 1984. pp. 89-94. Published
by NWWA, Worthington, Ohio. 1985.
Wolder Engineering. Southern California Edison
Underground Tank Study, Rosemead, California.
Wolder Engineering Project No. B261-00.
November 1985.
Young Jr., A. D. Underground Storage Tank Design
State-of-the-Art for 1986. Presented at HazPro
'86, Baltimore, Maryland. April 1936. Sponsored
by Pollution Engineering.
6-5
-------
-------
APPENDIX A
List of Vendors
The following vendor list provides the address, phone number, and the name of the technical
representative for each company identified in this report as a vendor of leak monitoring devices.
A-1
-------
Type of
Detector Company
Liquid Sensors
Grab Samplers
NEPCCO
Norton
(many others)
Chemical-Sensitive Paste
Kolor Kut
Products
McCabe
Interface Probe Monitor
Comar, Inc.
EMTEK, Inc.
Marine Moisture
Control
Oil Recovery
Systems, Inc.
Product Soluble Devices
EMTEK. Inc.
IFP Enterprise
In-Situ, Inc.
K&E Associates
Pump Engineer
Associates
Technology
2000, Inc.
Table A-1
List of Vendors
Technical
Address Representative
29 Wall Street
Foxboro, MA 02035
150DeyRoad
Wayne, NJ 07470
P.O. Box 541 5
Houston, TX 77262
76 Slope Dr.
Short Hills, NJ 07078
P.O. Box 832676
Richardson, TX 75083
27 Harvey Road
Bedford, NH 03201
60 Inip Dr.
Inwood, NY 11 696
220 Norwood Park S
Norwood, MA 02062
27 Harvey Road
Bedford, NH 031 02
680 Fifth Ave.
New York, NY 1001 9
21 OS. 3rd Street
Laramie, WY 82070
331 2 Industry Dr.
Long Beach, CA 90806
921 National Ave.
Addison, IL60101
265 Ballardvale St.
Wilmington, MA 01 887
Paul Guerra
..
D. Frauenberger
Joe McCabe
Bob Moorehead
Herold Solomon
Frank Giannone
Don Jones
Herold Solomon
C.E. Maier
Phil Gerhart
Jim Ridle
Matt Vetter
Donald Corey
Phone Number
617-543-8458
201-696-4700
713-926-4780
..
214-238-7691
603-627-3131
718-327-3430
800-645-7339
617-769-7600
603-627-3131
212-265-3800
307-742-8213
213-424-1517
312-543-2214
617-658-2900
Product Name
Liquid Samplers
and Bailers
Bailers
Water & Gasoline
Finding Pastes
Water & Gasoline
Indicator Pastes
•Models 807, 808
& 809 Tank Monitors
*PLD-17 Pipeline Monitor
Electronic Well Gauging
(EWGL-12) Light
Sonic Ullage
Interface Probe
Interface Probe
Detectron
Oil Fuse
Petrochemical
Release Monitors
PMS-800
Sentinel
TOLTECH Hydrocarbon
Monitor
Electrical Resistivity Sensors
Control
Devices
Total
Containment
2009-A West Detroit St.
Broken Arrow, OK 7401 2
15E. Uwchlan Ave.
Exton, PA 19341
Anthony Farque
Mike Webb
918-251-0387
215-524-9274
Wik-Stik
Total Containment
Cable-TC3000
A-2
-------
List of Vendors
Type of
Detector Company
*
Address
Thermal Conductivity Devices
FCI 1 755 LaCosta Meadows
San Marcos, CA 92069
Leak-X
Oil Recovery
Systems, Inc.
Pollulert
Systems
(Mallory)
Universal
Sensors and
Devices, Inc.
Vapor Sensors
Detector Tubers
MSA
National
Draeger, Inc.
Combustible Gas Detectors
MSA
Catalytic Sensor Devices
Bacharach
Instrument Inc.
Gas Tech, Inc.
Industrial
Scientific
Devices Corp.
Intek Corp.
Lumidor
Safety Products
Rexnord
Gas Detection
Products
560 Sylvan Ave.
Englewood Cliff, NJ 07632
220 Norwood Park South
Norwood, MA 02062
P.O. Box 706
Indianapolis, IN 46206
9205 Alabama Ave,
Unite
Chatsworth,CA91311
10770 Moss Ridge Rd.
Houston, TX 77043
P.O. Box 120
Pittsburgh, PA 15230
P.O. Box 426
Pittsburgh, PA 15230
625 Alpha Drive
Pittsburgh, PA 15238
8445 Central Ave.
Newark, CA 94560
355 Steubenville Pike
Oakdale, PA 15071
10410RockleyRd.
Houston, TX 77099
5364 NW 167th St.
Miami, Florida 3301 4
207 East Java Dr.
P.O. Box 3566
Sunnyvale, CA 94088
Technical
Representative
Malcolm McQueen
Bill Gelles
Don Jones
Wayne Pate
Wen Young
Patrick Kramer
Robert Dusch
Bruce Herman
Bill Milan
Bruce Holcom
Dave Kulawa
Ken Konrad
Norman Burnell
Greg Chambers
Phone Number
800-854-1993
615-744-6950
201-569-8989
617-769-7600
317-636-5353
818-998-7121
713-690-6268
800-672-2222
412-787-8383
412-967-3000
800-672-2222
412-963-2235
415-794-6200
412-788-4353
713-498-5855
305-625-651 1
408-734-1221
Product Name
785 Leak Detection
Systems
Leak-X System
CMS Variable
Level System
FD102andFD103
Leak Alert System
Samplair
Pump & Test Kit
Gas & Vapor
Detection Products
Several models
*TLV Sniffer
*Model 303
*Model H Gaspointer
Model 1238
LD-222
IGD
Model CRP-1
Combustible Gas
Detection System
A-3
-------
Type of
Detector
Company
Metal Oxide Semiconductors
API/Ronan
Armstrong
Monitoring
Azonic
Technology
Corp.
Calibrated
Instrument, Inc.
Enmet Corp.
Genelco, Inc.
Harco Corp.
International
Sensor Tech.
MSA
Oil Recovery
Systems, Inc.
Sierra Monitor
Universal
Sensors and
Devices, Inc.
U.S. Industrial
Products Co.
Product Permeable Devices
Teledyne
Geotech
Diffusion
W.L Gore
Sensors
Adsistor
Technology
Emco Wheaton
List
Address
12410 Benedict Ave.
Downey, CA 90242
215 Colonade Rd. South
Nepean, Ontario
Canada K2E 7K3
1671 Mabury Road
San Jose, CA 951 33
731 Saw Mill River Rd.
Ardsley, NY 10502
2308 S. Industrial Hwy.
Ann Arbor, Ml 481 04
11649 Chairman Dr.
Dallas, TX 75243
121 6 E. Tower Rd.
Schaumberg, IL60195
17771 Fitch St.
Irvine, CA 9271 4
600 Penn Center Blvd.
Pittsburgh, PA 15235
220 Norwood Park South
Norwood, MA 02062
1991 Tarob Court
Milpitas, CA 95035
9205 Alabama Ave.,
Unit C
Chatsworth, CA91311
13564 Pumice St.
Norwalk, CA 90650
3401 Shiloh Road
Garland, TX 75041
1 505 N. 4th St.
Flagstaff, AZ 86002
11300N.E.25thSt.
P.O. Box98115
Seattle, WA 981 25
Chamberlain Rd.
Conneaut, OH 44030
of Vendors
Technical
Representative
Matt Thomas
Bill Armstrong
Tom Gregory
John Mann
Elwood Boous
Michael Bouton
-
John Krell
Steve Long
Don Jones
Cathy Daigle
Wen S. Young
Samuel S. Wu
Philip Swiger
Art Molina
James Dolan
Chris Schauerman
Phone Number
--
—
408-729-4900
914-693-9232
313-761-1270
214-341-8410
312-882-3777
714-863-9999
412-776-8802
617-769-7600
408-262-661 1
818-998-7121
213-921-4342
214-271-2561
602-526-1290
206-523-6468
216-599-8151
Product Name
TRS 76
4200 Sensor
Enviro-Ranger
Pure Air Monitor
Several models
Soil Sentry
MultiRam12
AG5000&AG5100
Tankgard
VaporCMS
Model 201
Leak Alert
Tank Monitor
LASP System
LEAKLEARN
Adsistor Sensor
Leak Sensor II
Vapor Probe
A-4
-------
List of Vendors
Type of
Detector Company
Address
Technical
Representative
Phone Number Product Name
Diffusion Sensors (cont.)
EMMCp
Enterprises
Spearhead
Tech., Inc.
2525 Lehigh PI.
Costa Mesa, CA 92626
P.O. Box 51160
Seattle, WA 98115
Tom Meany
Bill Michaluk
714-545-6030
604-688-8245
Env. Control Safety
Monitoring System
STI2X12lnground
Tank Monitor
PIDs
AID, Inc.
Astro
Resources
HNU
Photovac, Inc.
Portable AID, Inc.
GCs
HNU
FIDs
Microsensor
Technology Inc.
Photovac, Inc.
Sentex Sensing
Tech., Inc.
XON Tech
Foxboro
Analytical
Infrared Foxboro
Analytical
Horiba
Engineering
Rt. 41 & Newark Rd.
Avondale, PA 19311
100 Park Ave.
League City, TX 77573
160 Charlemont St.
Newton Highlands,
MA 02161
741 Park Ave.
Huntington,NY11743
Rt. 41 & Newark Rd.
Avondale, PA 19311
160 Charlemont St.
Newton Highlands,
MA 02161
41762 Christy St.
Fremont, CA 94538
739B Park Ave.
Long Island, NY 11743
553 Broad Ave.
Ridgefield, NJ 07657
6862 Hayvenhurst Ave.
VanNuys, CA91406
330 Neponset Ave.
Foxboro, MA 02035
330 Neponset Ave.
Foxboro, MA 02035
121 DuryeaAve.
Irvine, CA 92714
Chuck Sarnoski 215-268-3181 Model 580
PhilLandon 713-332-2484 Trace Gas
Analyzer-1010
Omar Gendron 617-964-6690 Model P1101
Richard Smyth 516-351-5809 TIP "Underground
Tank Monitor
Chuck Sarnoski 215-268-3181 Model 590
Bob Pelletier 617-964-6690 Models 201,
301D and 501
Bob Turner
415-490-0900 Michromonitor
Richard Smyth 516-351 -5809 Photovac 10A10
Donna lanuzzi 201-945-3694 Scentor
Matt Young
818-787-7380 GC-810
Wendy Cotrell 617-543-8750 Century OVA
Wendy Cotrell 617-543-8750 Miran
Debbie Berardino 800-446-7422 IR Hydrocarbon
Gas Analyzer
A-5
-------
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-------OCR error (c:\conversion\JobRoot\000002LU\tiff\20006GVE.tif): Unspecified error
-------
3. Detection Capability (please specify units)
3a. Lower detection limit (sensitivity)
Can the sensitivity be adjusted, and if so, what is the range?
3b. Upper detection limit.
3c. Response Time_
Lag Time _
Rise Time.
Fall Time
Limitations (e.g., temperature) and their effect?.
3d. Drift
3e. Noise.
3f. Precision
3g. What test procedures were used to test for the above parameters?.
3h. How many sensors can operate from a single control box?.
3i. How often and for how long is each sensor on-line?
3j. Service Life of control box? Sensors?.
4. Experience
4a. Is leak detector presently being marketed?
If yes, for how many years?
4b. How many of your detection systems are now in service?.
4c. Has an actual leak ever been detected?
4d. Describe the operating experience of system users..
B-3
-------
Potential maintenance problems (e.g., ice in well, electrical malfunction sensor
deterioration)
Cause and frequency of false negative readings?.
Cause and frequency of false positive readings?
Estimate and Describe repair/replacement experience for control boxes and sensors
(if applicable)
5. Cost Information
5a. Capital cost of control box.
5b. Capital cost per sensor
5c. Installation cost of system for: (assume 4-tank facility)
New facility
Old facility
Existing monitoring well.
5d. Maintenance cost
6. Recommended Procedures
6a. Describe installation procedures.
6b. Is it necessary to install observation wells to use the detector?
B-4
-------
6c. Can the leak detection system be retrofitted to existing facilities?.
6d. Are site characterization studies prior to installation necessary/recommended?.
6e. What type of utility service is required for installation and operation of the leak detection
system?
6f. Where should the leak detector be placed in relation to the tank?.
6g. What distance should separate sensors from the tank and each other?.
6h. How many sensors should be used per tank/excavation?.
6i. Describe calibration procedures to be performed at time of installation.
6j. What instrument settings are adjusted at time of installation (e.g., background
adjustments)?
Describe how and why this is done..
6k. Can the system be operated in unsaturated, saturated (wet), and/or intermittent
(saturated or unsaturated) soil condition? Specify!
61. Describe operating procedures.
B-5
-------
6m. Describe recommended operating environment (e.g., non-explosive atmosphere).
Give allowable operating ranges for temperature, input voltage, etc.
6n. Maintenance requirements?
60. Maintenance schedule?
6p. Calibration procedures?.
6q. Calibration schedule?
6r. Recommended sample flow rate and allowable variability?
6s. Is there any method to certify the performance of the system? If yes, include
representative certification data and discuss how base-line values for certification
were established.
6t. Describe if and how the leak detect system differentiates between surface spills and
underground leaks.
Please return completed survey form In the envelope provided to:
Radian Corporation
P.O. Box 9948
Austin, TX 78766
Attn: Mr. Bart Eklund (3)
Please direct any questions or comments to:
Mr. Bart Eklund (512) 454-4797
Mr. Walt Crow (512) 454-4797
B-6
-------
APPENDIX C
Tabulated Survey Results
C.1 Tabulated Results From Survey
The survey responses have been tabulated following the format of the questionnaire. The tables give the
response from each vendor for each type of device. Results were summarized in Section 3. Where the vendor
left a question blank on the survey form, the term "No Response" or "N/R" is listed in the tables. Where the
answer provided by the vendor was too lengthy or complicated to be tabulated, the term "Given" is listed in the
Tables C-1 through C-6. Where vendors responded with multiple questionnaires describing similar products
based on the same principle of operation, answers are given for the most suitable gas leak detector (i.e., the
most sensitive or the least expensive). Products and companies listed in Table 3-1 as not having submitted a
survey form are omitted from these tables.
The estimated costs associated with each leak monitoring technique derived from the vendor responses are
given in Table C-5. The installation costs provided by vendors are thought not to be based on uniform
assumptions and therefore should not be directly compared. Costs of well drilling, labor, utility service, cable,
etc., seem not to be addressed by some vendors.
C-1
-------
Type of Detector
Table C-1
Vendor Responses for Principle of
Operation of Leak Monitoring Techniques
Company Principle of Operation
Continuous Liquid-Phase
Interface Probes Comar, Inc.
Product Soluble EMTEK, Inc.
Devices In-Situ, Inc.
K&E Associates
Technology 2000, Inc.
Electrical Resistivity Total Containment
Thermal
Conductivity
Leak-X
Pollulert Systems (Mallory)
Universal Sensors &
Devices, Inc.
Intermittent Gas-Phase
Portable GC's
Infrared
PID's
AID, Inc.
HNU
Photovac, Inc.
XON Tech
Horiba Engineering
AID, Inc.
Astro Resources Int.
HNU
Photovac, Inc.
Continuous Gas-Phase
Catalytic Sensors Bacharach Instrument Co.
Industrial Scientific Devices
Intek Corp.
Rexnord Gas Detection
Products
Diffusion
Adsistor Technology
Emco Wheaton
EMMCO Enterprises
Spearhead Tech., Inc.
Fiber optic sensor
Softening of hydrocarbon-sensitive material/float-switch
Destruction of sensing element by petrochemical/electrical
contact
Combined control system
Softening of hydrocarbon-sensitive material/float-switch
Deterioration of dielectric insulation on twisted pair of woven
conductors
Conduction
AC Conductivity
Thermal cooling
Photoionization
Photoionization
Photoionization
GC/Electron capture detector
Non-dispersive infrared analysis
Photoionization
Photoionization
Photoionization
Photoionization
Catalytic combustion of explosive vapors on a platinum coated
bead
Catalytic bead platinum wire combustible sensor with
wheatstone bridge
Catalytic combustion of hydrocarbon vapors
Catalytic bead type combustible gas detection system
Adsorption sensor
Adsorption sensor
Physicochemical adsorption
Adsorption sensor
Metal Oxide
Semiconductors
Product Permeable
Devices
Armstrong Monitoring
Azonic Technology, Inc.
Calibrated Instrument, Inc.
Genelco, Inc.
MSA
Universal Sensors and
Devices, Inc.
U.S. Industrial Products
Teledyne Geotech
Cherrfical absorption on semiconductor material
Bulk semiconductor vapor sensor
Taguchi cell (metal-oxide semiconductor)
Aspirated vapor sensor
Metal-oxide semiconductor sensor
Metal-oxide semiconductor sensor
Solid-state sensor
Gas permeable cable, pump, and metal-oxide semiconductor
C-2
-------
Table C-2
Vendor Responses for Detection Specificity of Leak Monitoring Techniques
Detection
Type of Adjustable Potential False
Tvoeof Detects Compound For Specific Inter- Positive or
Detector Company Gas Liquid Detected Compounds ferences Negatives
Continous Liquid-Phase
Interface Comar, Inc. No Yes
Probes
Product EMTEK, Inc. No Yes
Soluble
Devices In-Situ, Inc. Yes Yes
K&E Assoc. Yes Yes
Technology No Yes
2000, Inc.
Electrical Total Yes Yes
Resistivity Containment
Thermal Leak-X No Yes
Conduc-
tivity Pollulert Yes Yes
Systems
(Mallory)
Universal No Yes
Sensors &
Devices, Inc.3
Intermittent Gas-Phase
Portable AID, Inc. Yes No
GC's
HNU Yes No
Photovac, Inc. Yes No
XON Tech Yes Yes
Infrared Horiba Yes No
Engineering
PID's AID, Inc. Yes No
Astro Yes No
Resources Int.
HNU Yes No
Photovac, Inc. Yes No
aThe questionnaire returned by Universal
metal-oxide semiconductor sensor. The
Hydrocarbons
-------
Vendor Responses for Detection
Type of
Detector
Continuous
Catalytic
Sensor
Diffusion
Metal Oxide
Semicon-
ductors
Detects
Company Gas Liquid
Gas-Phase
Bacharach Yes
Instrument
Co.
Industrial Yes
Scientific Devices
Intek Corp. Yes
Rexnord Gas Yes
Detection Products
Adsistor Yes
Technology
Emco Wheaton Yes
EMMCO Yes
Enterprises
Spearhead. Yes
Tech., inc.
Armstrong Yes
Monitoring
AzonicTech., Yes
Inc.
Calibrated Ins., Yes
Inc.
Genelco, Inc. Yes
MSA Yes
No
No
No
No
Yes
Yes
Yes
Yes
No
Yes
No
No
No
Universal No Yes
Sensors & Devices, Inc.3
Product
Permeable
Devices
U.S. Industrial Yes
Products Co.
Teledyne Yes
Geotech
No
No
•™™^^^™i™™""m*"««»™™<«i""'™^»^^^^^^^^^^^«^^^^^^B™^M^^^^m^^^^^m— ^^^^^ w^j2j^^5^^^^2™™^SSS™"S2
Table C-2
Specificity of Leak Monitoring Techniques (Continued)
Type of
Compound
Detected
Hydrocarbons
Hydrocarbons
HCs, H2, NH3
Hydrocarbons
Hydrocarbons
Hydrocarbons,
Acetone
Hydrocarbons
Given
Hydrocarbons
Given
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Hydrocarbons
Detection
Adjustable Potential
For Specific Inter-
Compounds ferences
No
No
No
Yes
Yes
No
Yes
Yes
No
Yes
No
No
No
No
Somewhat
No
H2O,CH4,
CO2,CO,
O2,S
Pb,Si,S,O2
Si.Esters,
Phosphates
HO.CI
None
H2S
None
None
CH4,S
CH4> H2O
CH4, H2O
CH4,CO
CH4,S,CO
CH4,CO
Sulfur
Compounds
None
False
Positive or
Negatives
Both
Both
Both
Both
None
n/a
None
No
Pos.
Both
Pos.
Neg.
Pos.
Pos.
Pos.
Yes
Severity of
Interferents
Only if
<10%O2
Variable
Variable
n/a
Gas Dis-
placement
Given
n/a
None
Only at
Explosive
Levels
Temporary
Given
Not
Specified
Normally low
n/r
Minimal
n/r
a The questionnaire returned by Universal gave a combined answer for both their thermal conductivity sensor and their
metal-oxide semiconductor sensor. The stated values are repeated in the table for both types of sensor.
======^^
C-4
-------
Table C-3
Vendor Responses for Detection
Capability of Leak Monitoring Techniques
Type of Detection Limit
Company Lower
Continuous Liquid-Phase
Interface Probe
Comar, Inc. 1 Qt.
Product Soluble Devices
EMTEK, Inc. <0.25 in.
In-Situ, Inc. 3.4mg/L Vap.
.079 mm Liq.
K&E Assoc. 1 00 ppm
Technology 1/64 in.
2000, Inc.
Electrical Resistivity
Total n/a
Containment
ThermalConductivity
Leak-X 5/8 in.
Pollulert Systems 1/8in.(liq)
(Mallory) 100ppm(gas)
Universal 200 ppm
Sensors &
Devices, Inc.
Intermittent Gas-Phase
Portable GC's
AID, Inc. 10ppb
HNU .001-1 ppm
Photovac, Inc. 1 ppb
XON Tech Variable
Infrared
Horiba 0-50 ppm
Engineering
PID's
AID, Inc. 0.1 ppm
Astro 0.1 ppm
Resources Int.
HNU .001-1 ppm
Photovac, Inc. 0.05 ppm
. .
Adjustable
No
No
Yes
Yes
No
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
No
n/r
Yes
Yes
Sensors
Par r.nntrnl
Upper Box
None 4
None 10
Unlimited 4
5,000 ppm 15
None 4
n/a 25 miles
of cable
8ft. 10
2 in. or 10-15
5,000 ppm
7,500 ppm 8-32
2,000 ppm 1
1.5-1 50 ppt 1
500 ppm 1
Variable n/a
100% 1
20,000 ppm 1
999.9 ppm 1
1.5-1 50 ppt 1
20,000 ppm 32
^M^KKl^H^WB^^^^^^^^^HHMBi^HnMM«mBi
Service
On-Line Control
Time Box
Continuous >3 Yrs.
Continuous Indefinite
Leak
Continuous >20 Yrs.
Continuous 7.5 Yrs.
Continuous 5 Yrs.
Continuous Indefinite
Continuous 3 Yrs.
Continuous 1 Yr.
(warrant)
Continuous >5 Yrs.
Continuous Not known
Continuous >5 Yrs.
n/a 5-10 Yrs.
n/a n/a
Continuous Indefinite
n/r Not known
Life
Sensors
>5 Yrs.
Until Detect
>20 Yrs.
12 Yrs.
Inspect
Annually
Indefinite
2 Yrs.
Many Yrs.
>8 Yrs.
1 0,000 Hrs.
>5 Yrs.
18 MO.
n/a
Indefinite
10,000 Hrs.
Continuous Unavailable 2yrs.
Continuous >5 Yrs.
4@ 5-10 Yrs.
(15sec/hr.)
>5 Yrs.
1 Yr.
C-5
-------
Table C-3
Vendor Responses for Detection
Capability of Leak Monitoring Techniques (continued)
Type of Detection Limit
Company Lower
Continuous Gas-Phase
Catalytic Sensors
Bacharach 50 ppm
Instrument
Industrial 0% LEL
Scientific
IntekCorp. 0.1%HC
Rexnord Gas 5% LFL
Detection
Products
Diffusion Sensors
Adsistor 1 00 ppm
Technology
Emco Wheaton 1 00 ppm
EMMCO List
Enterprises
Spearhead 1 00 ppm
Tech., Inc.
Metal Oxide Semi-Conductors
Armstrong ppm Range
Monitoring
Azonic 10-20 ppm
Technology Gasoline
Calibrated 1 ppm
Instrument
Genelco, Inc. 25 ppm
MSA 10 ppm
Universal 200 ppm
Sensors &
Devices, Inc.
Adjustable
No
n/r
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
Sensors
Upper Box
2,000 ppm 1
100% Lei n/a
LFL 4
LFL 1-8
100% No limit
100% 16
Pure liquid 10
100% 4 or 12
Cone.
Lower %'s 12
8,000 ppm 1
>500 ppm 1
8,000 ppm 1
n/a 4
7,500 ppm 8-32
Service
I On-Line Control
Time Box
Intermittent Indefinite
n/a n/a
Continuous n/a
Continuous 10Yrs.
u/sec n/r
Continuous 10Yrs.
Continuous Indefinite
Continuous 1 0 Yrs.
Continuous 20 Yrs.
32 min 5-7 Yrs.
Intervals
n/r n/r
7 min./? 5-10 Yrs.
Continuous >10Yrs.
Continuous >5 Yrs.
Life
Sensors
>1 Yr.
1 Yr.
1-10 Yrs.
2-3 Yrs.
>10Yrs.
>10Yrs.
Indefinite
>10Yrs.
10 Yrs.
40 Hrs.
@ 1 .5 yrs.
5 Yrs.
>5 Yrs.
>8 Yrs.
U. S. Industrial 2 ppm No 100% Lei 16
Products Co.
Product Permeable
Teledyne <20ppm n/r n/r 1
Geotech
Continuous >10Yrs. >3Yrs.
Adjustable Not known 5 Yrs.
C-6
-------
Table C-3
Vendor Responses for Detection
Capability of Leak Monitoring Techniques (Continued)
Type of Detector/ Response Lag Rise Fall Test
Company Time Time Time Time Drift Noise Precision Procedures
Continuous Liquid-Phase
Interface
Comar, Inc. @ 30 min. n/a n/a
Product Soluble Devices
EMTEK, Inc. Instant <1 min. n/a
In-Situ, Inc. 0.5-23 n/a n/a
min. (liq.)
K&EAssoc. 5 sec. NIL <.5sec.
Technology Variable n/a n/a
2000, Inc.
Electrical Resistivity
Total Contain. Given Given Given
Thermal Conductivity Devices
Leak-X Immediate 5 sec. n/a
Pollulert Instant Instant Instant
Systems (Mallory)
Universal Instant <1 MIN.
Sensors & Devices, Inc.
Intermittent Gas-Phase
Portable GC's
AID, Inc. Variable n/r n/r
HNU <3sec Negl. Negl.
Photovac, 1-10 min. 1 min. 1 min.
Inc.
XONTech n/a n/a n/a
Infrared
Horiba 30 sec. 30 sec. 30 sec.
Engineering
PID's
AID, Inc. 3 sec. Var. Var.
Astro Instant n/r n/r
Resources Int.
HNU <3sec Negl. Negl.
Photovac, 3 sec. 5 sec. 3 sec.
Inc.
n/a None None 100% Yes
n/a n/a n/a n/a n/a
n/a None None n/r Ind. Lab
<6min. None None 1.1% Cycle Test.
n/a n/a n/a n/a Given
Given n/a n/a n/a Given
n/a n/a n/a n/a NBS.UL.etc.
Instant n/a n/a Given Given
<3MIN. +/-10% +/-2% +/1 10% Given
n/r Minimal Minimal Var. Std. Gas
Negl. <1 % <1 % +/- 1 0% Known
Samples
1 min. Compen- 1 :4 3-5% Std. Gas
sated
n/a Minimal Minimal Good Std. Gas
30 sec. 2%/Day 1%of 1%of Std. Gas
Full Scale Full Scale
Var. Not Not Var. Std. Gas
Known Known
n/r n/a n/a 0.1 ppm Propylene
(gas)
Negl. <1 % <1 % +/- 1 0% Known
Samples
7 sec. 1 ppm/hr. 0.1 ppm 1% Std. Gas
Limitations I
None
>32F
Temp.
Tests
-
Temp.
Given
Liq. Only
Temp.
Temp. &
Humidity
Temp.
n/r
Temp.
-
Temp.
Temp.
Temp.
n/r
Temp, or
Humidity
C-7
-------
Table C-3
Vendor Responses for Detection
Capability of Leak Monitoring Techniques (Continued)
Type of Detector/ Response Lag Rise
Company Time Time Time
Continuous Gas-Phase
Catalytic Sensor Devices
Bacharach 30 sec. n/r n/r
Instrument Co.
Industrial 12 sec. n/r n/r
Scientific Devices
IntekCorp. 10 sec. 2-3 sec. 7 sec.
Rexnord <20sec. n/a n/a
Gas Detection
Products
Diffusion Sensors
Adsistor 1 sec. msec. msec.
Technology
Emco 5 sec. 5 sec. 5 sec.
Wheaton
EMMCO - - instant
Enterprises
Spearhead Given Given Given
Tech., Inc.
Metal Oxide Semiconductors
Armstrong Immed. n/a n/a
Monitoring
Azonic 20 sec. n/r n/r
Tech. Corp.
Calibrated <1 sec. <1 sec. <1 sec.
Instrument, Inc.
Genelco, Inc. Immed. Immed. 20 sec.
MSA <1 0 sec. <1 sec. <1 0 sec.
Universal -- Instant <1 MIN.
Sensors
and Devices, Inc.
U.S. 30 sec. 3-10 sec. 5 sec.
Industrial
Products Co.
Product Permeable Devices
Teledyne n/r n/r n/r
Geotech
Fall
Time Drift Noise
n/r +/-250ppm 0-50
for 10 min. ppm
n/r n/r n/r
20 sec. 2% 1%LFL
LFL/mo.
<30 sec. Negl. n/a
seconds No No
15 sec. n/a Compen-
sated
Var. None Compen-
sated
Given None None
30 sec. +/- 8% NIL
n/r 1 uV/C 120dB
<1 sec. Not Not
Known Known
< 15 min n/r n/r
<10sec. n/a n/a
<3 MIN. +/-10% +1-2%
45-60 sec. <5%/Yr. No
n/r n/r n/r
Precision
+/- 5%
1%
+/- 5%
+/- 3%
Yes
n/a
+/-10mV
Unspeci-
fied
+/- 8%
1%
Not
Known
n/r
n/a
+/1 10%
2%
n/r
Test Pro-
cedures
Factory
Testing
n/r
Standard
Given
Various
Std. Gas
Yes
Given
Confiden-
tial
Factory
Test
Lab Tests
Gas Stds.
n/a
Given
n/a
n/r
Limit-
ations
25 min.
warm-up
Temp.
None
-
High
Temps
Temp.
n/a
Given
NIL
n/r
Temp.
n/r
None
Temp. &
Humidity
n/a
n/r
C-8
-------
1
Vendor Responses
Type of Product
Detector/ On
Company Market
Continuous Liquid-Phase
Interface Probe
Comar, Inc. Yes
Product Soluble Devices
EMTEK, Inc. Yes
In-Situ, Inc. Yes
K&E Assoc. Yes
Technology, Yes
2000, Inc.
Electrical Resistivity
Total Yes
Containment
Thermal Conductivity
Leak-X Yes
Pollulert Yes
Systems (Mallory)
Universal Yes
Devices, Inc.
Intermittent Gas-Phase
Portable GC's
AID, Inc. Yes
HNU Yes
Photovac, Inc. Yes
XON Tech Yes
Infrared
Horiba Yes
Engineering
PID's
AID, Inc. Yes
Astro No
Resources Int.
HNU Yes
Years
On
Market
1/2
1
1/4
2
1/4
15
10
Not
Given
2
1
8-10
10
6
10
7
n/r
8-10
•
Table C-4
for Experience of Leak Monitoring Techniques
No. in
Service
12
3
0
200
0
400-500
1000's
Has Leak
Been
Found?
No
Yes
No
Yes
No
Yes
Yes-
Many
1000's Yes
1,300
10
@ 3,500
100's
@50
100's
n/r
Unavailable
@ 3,500
Yes
Yes
Yes
Yes
Not
known
Yes
Yes
Yes
Yes
Maint.
Problems
None
Ice
None
Ice, Elec.
Severe
Deterioration
None
Improper
Installation
Cleaning
None
Columns
Water
Columns
Not
known
n/a
Water, Dirt
Calibration
Water
Cause of
False
Negatives
Break in
Cable
n/a
n/a
n/a
None
None
Elec.
Short
No
Response
Not
Known
None
Application
Dependent
Not likely
Not known
n/a
Moisture
n/a
Application
Dependent
Cause of
False
Positives
n/a
n/a
n/a
Back-
ground
Mech.
Failure
None
n/a
No
Response
Not
Known
None
Application
Dependent
Interferences
Not known
Interferences
Not known
Interferences
From Gases
Application
Dependent
C-9
-------
„ „ Table C-4
vendor Responses for Experience of Leak Monitoring Techniques (continued)
Type of Product Years
Detector/ On On
If Company Market Market
PID's(cont.)
Photovac, Inc. No 2 (TIP)
Continuous Gas-Phase
Catalytic Sensors Devices
Bacharach Yes 1
Instrument Co.
Industrial Yes 5
| Scientific Devices
1
Intek Corp. Compo- 7
nent Only
RexnordGas Yes 15
Detection Pds.
Diffusion Sensors
Adsistor Yes 10-20
Technology
EmcoWheaton Yes 1.5
EMMCO Yes 12
Enterprises
Spearhead Yes Given
Tech., Inc.
Metal Oxide Semiconductors
Armstrong Yes 5
Monitoring
Azonic Yes 0.5-1
Tech. Corp.
Calibrated Yes 12
Instrument, Inc.
Genelco, Inc. Yes 1.5
MSA Yes Just
Started
Universal Yes 2
Sensors & Devices, Inc.
U.S. Industrial Yes 1
Products Co.
Product Permeable Devices
Teledyne Yes 4
Geotech
No. in
Service
100's
100
n/r
>20,000
>50,000
75,000
200
0
(50,000)
35
n/a
10-15
Not
Known
30
Test Units
Only
1,300
n/a
1 (tank)
4 (pipeline)
Has Leak
Been
Found?
Yes
Yes
Yes
Yes
Yes
2 In
Ground
Yes
Yes
Yes
Yes
Yes
n/r
Yes
Yes
Yes
n/a
Yes
Maint.
Problems
Dust Filter
None
None
Several
(given)
Several
(given)
n/a
n/a
0-60 C
Given
None
To Date
Several
Listed
n/r
None
Observed
None
Given
n/a
Given
Cause of
False
Negatives
None
?
None
No specific
Zero Drift
VAC
n/a
None
None
None
Old Sensor
Several
(<1%)
n/r
None
To Date
None
Known
Not
Known
Temperature
Sensor Break
Cause of
False
Positives
Interferences
Below 100ppm
Interferences
None
No specific
Temperature
n/a
None
Electrical
Malfunction
Given
n/a
<1%
n/r
None
To Date
None
To Date
Not
Known
No
:
n/a
^^
C-10
-------
^-sssssss^s^s^sss^^^s^ss^ss^ssssss^ss^sss^sss^sss
Table C-5
Vendor Responses for Cost of Leak Monitoring Techniques
Type of Capital Costs Installation Costs -$ (4 Tanks)
Company Control Box
Continuous Liquid-Phase
Interface Probe
Comar, Inc. 1 ,200
Product Soluble Devices
EMTEK, Inc. 1,195
In-Situ. Inc. 395
K&E 1,175
Associates
Technology 1,400
2000, Inc.
Electrical Resistivity
Total 1,495
Containment
Thermal Conductivity Devices
Leak-X 1,400
Pollulert Systs. n/r
(Mallory)
Universal 1,000-1,600
Sensors & Devices, Inc.
Intermittent Gas-Phase
Portable GC's
AID, Inc. 5,850
HNU n/r
Photovac, Inc. 8,000
- 14,000
XON Tech n/a
Infrared
Horiba 1,750
Engineering - 9,000
PID's
AID, Inc. 3,880
Astro 4,125
Resources Int.
HNU n/r
Photovac, Inc. 6,300
Sensor
200
260-DW Tank
195-245
475
900
85-185
625-725
n/r
200-800
398
n/r
n/a
5,000-12,000
n/a
398
1,675
n/r
200
New Facility
1,200
>2,200
600-Well
1,500-2,000
>2,500
11,000
2,820
2,500
Minimal
1,400
Var.
@20,000
Var.
n/a
1,750-30,000
Not Known
n/r
@ 20.000
n/r
Old Facility
1,200
>3,600
3,000
- 7,000
>4,500
7,000
- 1 1 ,000
5,520
5,500
Var.
4,900
Var.
@ 20.000
Var.
n/a
1.750
- 30,000
Not Known
n/r
@ 20,000
7,500
Old Well
200
>3,600
1,500
- 2,000
500
7,000
3,320
4,200
Same As
Equipment
1,600
None
@ 20,000
Var.
n/a
n/r
None
n/r
@ 20.000
7,000
======
Maintenance
Cost$
NIL
None
None
<50/Yr.
100
n/r
600/Yr.
2 Man Hours
300/Yr.
Minimal
<5%/Yr.
600/Yr.
Not Known
Var.
Minimal
n/r
<5%/Yr.
600/Yr.
C-11
-------
• l^^>^^^^HMIKi^HMNWHMMtt«MH«HMHBnnM^^MnMI^^Hil^MM^HMIM^H^^^MHH^MMM
Table C-5
Vendor Responses for Cost of Leak Monitoring Techniques (Continued)
Type of Capital Costs
Company Control Box
Continuous Gas-Phase
Catalytic Sensor Devices
Bacharach 895
Instrument Co.
Industrial n/a
Scientific Devices
Intek Corp. 950-1 ,300
Rexnord Gas 700-2,400
Detection Products
Diffusion Sensors
Adsistor n/a
Technology
Emco Wheaton 1 ,400
EMMCO 1,950
Enterprises - 4,200
Spearhead 2,450
Tech., Inc. - 3,540
Metal Oxide Semiconductors
Armstrong 420
Monitoring
Azonic 1 ,500
Technology - 4,000
Corp.
Calibrated <1 ,000
Instrument, Inc.
Genelco, Inc. 1,500
- 4,000
MSA 985
Universal 1,000
Sensors & -1,600
Devices, Inc.
U.S. Industrial >1,300
Products Co.
Product Permeable Devices
Teledyne 5,000
Geotech
Sensor
65
<100
@180
125
n/a
200
250
200-300
28
1,000-1,500
n/r
Included
94
200-800
145
6/ft.
Installation Costs - $ (4 Tanks)
New Facility Old Facility Old Well Cost $
n/a n/a n/a n/r
n/a n/a n/a n/a
n/r n/r n/r n/r
Same As Same As Same As Low
Equip. Cost Equip. Cost Equip. Cost
n/a n/a n/a n/a
Given Given Given Minimal
>3,700 >3,700 >3,500 0-150/Mo.
1,000-1,200 3,000 1,200-1,500 1,400/Yr.
NIL
3,000-7,500 3,000-7,500 3,000-4,700 300/Yr.
n/r n/r n/r n/r
Var. Var. Var. Var.
NotEstab. NotEstab. n/r Near Zero
1,400 4,900 1,600 300/Yr.
n/a n/a 3,200-3,600 n/a
n/r n/r n/r Negl.
===!==s=========^^ -----
C-12
-------
Table C-6
Vendor Responses For Recommended
Procedures For Leak Monitoring Devices
Type of
Detector/
Company
Are Wells
Required?
Continuous Liquid-Phase
Interface Probe
Comar, Inc. Yes
Product Soluble Devices
EMTEK, Inc.
In-Situ, Inc.
K&E Assoc.
Technology
2000, Inc.
Electrical Resistivity
Total
Containment
Yes or
DWTank
No
Yes
No
Yes
ThermalConductivity Devices
Leak-X Yes
Pollulert
Systems (Mallory)
Universal
Yes
Yes
Can
System be
Retrofitted?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Recommend
Site Study
Unnecessary
Yes
Yes
No
Yes
Yes
Yes
As Required
Yes
Utility
Service
None
11 5/230 V
60Hz
None
120 VAC
110VAC
11 0-1 20 VAC,
50/60 Hz
120 VAC
110V
115VAC
Location
To Tank
Downgradient
4 Corners
Downgradient
-
Downgradient
In Excavation
2 Ft. Below
2 Ft. Below
Within 15 Ft.
Distance
From Tank
Perimeter
VAR.
VAR.
Within 5 Ft.
Close
2 Ft.
2 Ft.
Close
<15Ft.
Sensors & Devices, Inc.
Intermittent Gas-Phase
Portable GC's
AID, Inc.
HNU
Photovac, Inc.
XON Tech
Infrared
Horiba
Engineering
PID's
AID, Inc.
Astro
Resources Int.
HNU
Photovac, Inc.
No
No
No
Not Known
Yes
Yes
n/a
No
Yes
Yes
Yes
Yes
Not Known
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Not Known
No
Yes
Yes
No
10VAC,
12VDC
110V, 60Hz
None
110V
115V,60Hz
None
AC Power
110V.60HZ
110 VAC
n/a
Up To User
Downgradient
Not Known
n/a
n/a
As close as
Possible
Up to User
Above Water
Table
100 Ft.
n/a
n/a
VAR.
n/a
n/a
20-30 Ft.
h/a
50 Ft.
C-13
-------
Table C-6
Vendor Responses For Recommended
Procedures For Leak Monitoring Devices (Continued)
Type of
Detector/
Company
Continuous Gas-Phase
Catalytic Sensor Devices
Bacharach
Instrument Co.
Industrial
Scientific Devices
Intek Corp.
Rexnord Gas
Detection Products
Diffusion Sensors
Adsistor
Technology
Emco Wheaton
EMMCO
Enterprises
Spearhead
Tech., Inc.
Are Wells
Required?
Yes
(Barhole)
n/a
Sometimes
n/a
Sometimes
Yes
No
Metal Oxide Semiconductors
Armstrong No
Monitoring
Azonic
Technology Corp.
Calibrated
Instrument, Inc.
Genelco, Inc.
MSA
Universal
Sensors &
Devices, Inc.
U.S. Industrial
Products Co.
Yes
n/r
No
Yes
Yes
No
Product Permeable Devices
Teledyne No
Geotech
Can
System be
Retrofitted?
Yes
n/a
Yes
n/a
Yes
Yes
Yes
Yes
Yes
n/r
Yes
Yes
Yes
No
Yes
Recommend
Site Study
No
n/a
Yes
n/a
Yes
Yes
Yes
Yes
Yes
n/r
Yes
No
Yes
No,
Yes
Utility
Service
None
n/a
„ 1 1«
1 1 VAC or
20-28 DC
n/a
115 VAC
<15AMP
VAR.
Given
110-120VAC,
60Hz
None
n/r
115 VAC
Elec Power
115VAC
~
n/r
Location
To Tank
n/r
n/a
VAR.
n/a
Above Water
Table
Under
Given
In
Excavation
Backfill
n/r
See Manual
See Manual
Within 15 Ft.
Given
As Close as
Possible
Distance
From Tank
n/r
n/a
VAR.
n/a
Variable
Close
Proximity
Given
1 Ft. Below
None
Specified
n/r
1 Ft.
See Manual
<15Ft.
1 Ft.
n/r
C-14
-------
Table C-6
Vendor Responses For Recommended
Procedures For Leak Monitoring Devices (Continued)
Type of
Detector/
Company
No. of
Sensors
Per Tank
Calibration
Procedures
Adjustable
Instrument
Settings
Use In
Wet Soil
Operating
Environment
Temperature
Range
Voltage
Range
Continuous Liquid-Phase
Interface Probe
Comar, Inc.
Product Soluble
EMTEK, Inc.
In-Situ, Inc.
K&E Assoc.
Technology
2000, Inc.
Electrical Resistivity
Total
Containment
Thermal Conductivity
Leak-X
Pollulert Systs.
(Mallory)
Universal
1-4
4
Var.
1-4
4
4
None
Pump Test
None
Given
Given
None
None
None
None
Yes
None
None
Yes
Yes
Yes
Yes
Yes
Yes
Any
Syst. is Safe
Any
n/a
Given
Any
-50°-140°F
None Given
No Limits
30" -1 20° F
-4°-122°F
32° -250° F
n/a
None Given
n/a
85-1 35V
95-1 30 Vac
11 0-1 20 Vac
120° -150° (cable)
Every 15 Ft.
4
Every 15 Ft.
None
None
None
None
None
Trimpots
Yes
Yes
Yes
Any
Given
Non-explosive
-40° - 50° C
-40° - 50° C
32°-125°F
100-1 40 Vac
100-1 40 Vac
105-1 25 Vac
Sensors & Devices, Inc.
Intermittent Gas-Phase
Portable GC's
AID, Inc.
HNU
Photovac, Inc.
XON Tech
Infrared
Horiba
Engineering
PID's
AID, Inc.
Astro
Resources Int.
HNU
Photovac, Inc.
1
1 or more
1
Not known
n/a
n/a
Var.
1 or more
1-6
Gas Std.
n/a
Cal. Gas
Cal. Gas
Std. Gas
Cal. Gas
N2+C3H8
Gas Stds
n/a
Cal. Gas
None
Zero/Span
Several
Not known
Zero/Span
None
Zero/Span
Zero/Span
Several
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Non-explosive
Given
Non-explosive
Room Temp.
Given
Non-explosive
Clean, Temp
Controlled
Given
Given
0°-40°F
n/r
40°-120°F
RT-200° C
Given
0° - 45° C
-10°-+50°C
n/r
30 °-1 20° F
n/r
n/r
115 AC or
12V DC
110V
11 0-1 30V
115 Vac,
12V DC
110Vac,
60Hz
n/r
1 10-120 V
C-15
-------
Table C-6
Vendor Responses For Recommended
Procedures For Leak Monitoring Devices (Continued)
Type of No. of
Detector/ Sensors
Company Per Tank
Continuous Gas-Phase
Catalytic Sensor Devices
Bacharach n/r
Instrument Co.
Industrial n/a
Scientific Devices
Rexnord Gas Var.
Detection Prods.
Diffusion Sensors
Adsistor n/a
Technology
Emco Wheaton 1 or more
EMMCO 1 or more
Enterprises
Spearhead Given
Tech., Inc.
Metal Oxide Semiconductors
Armstrong 1 -2
Monitoring
AzonicTech. 1-2
Corp.
Calibrated n/r
Instrument, Inc.
Genelco, Inc. 2
MSA 4
Universal Every 1 5 Ft.
Sensors &
Devices, Inc.
U.S. Indust. 1-2
Products Co.
Product Permeable Devices
Teledyne 2
Geotech
Calibration
Procedures
Cal. Kit
n/a
Adjustable
Instrument
Settings
Several
n/a
See
Manual
n/a
None
"A"
Constant
Given
n/a
See
Manual
n/r
Self-Calibrat
See Manual
None
Zero/Span
None
None
n/a
Trip point
"A"
Constant
Given
None
See
Manual
n/r
Several
Several
Trimpots
None
Gain/Zero
Use In
Wet Soil
Yes
n/a
•^
Yes
n/a
Yes
Yes
Yes
Yes
Not in
Saturated
n/r
Yes
Yes
Yes
Yes
Yes
Operating
Environment
Intrinsically
Safe
Any
OK for
Hazardous
Controller in
Non-hazard.
Air
Controller in
Non-hazard.
NFPA Classl
Air
Non-
explosive
Non-
explosive
n/r
Indoors
Intrinsically
Safe
Non-
explosive
Given
Any
Temperature
Range
-4°- 122° F
-10°-45°C
-20° - 60« c
-40° - 85° C
-100°-160°F
-40° - 70° C
Not Specified
-100°-160°F
n/r
0°-125°C
n/r
Not Specified
-5°-140°F
32°-125°F
-10°- 150° C
n/r
Voltage
Range
n/a
n/a
n/r
105-1 30 Vac
20-28 DC
mV-12V
n/r
105-1 25 Vac
110V
n/r
n/r
n/r
105-1 25 Vac
11 0-1 25 Vac
105-1 25 Vac
3VDC
n/r
C-16
-------
Table C-6
Vendor Responses For Recommended
Procedures For Leak Monitoring Devices (Continued)
Type of
Detector/ Maintenance
Company Requirements
Continuous Liquid-Phase
Interface
Comar, Inc. None
Product Soluble
EMTEK, Inc. n/a
In-Situ, Inc. Inspect
K&E System Test
Associates
Technology Inspect
2000, Inc.
Electrical Resistivity
Total None
Containment
Thermal Conductivity
Leak-X Inspect
Pollulert Systs. Clean Probes
(Mallory)
Universal Not Given
Sensors & Devices, Inc.
Intermittent Gas-Phase
Portable GC's
AID, Inc. Given
HNU n/r
Photovac, Inc. Given
XON Tech Minimal
Infrared
Horiba Day/Month
Engineering
PID's
AID, Inc. Clean Lamp
Astro Calibration
Resources Int.
HNU n/r
Photovac, Given
Inc.
Maintenance
Schedule
2Yrs.
n/a
Weekly
For 1 min.
As Required
Annual
None
60 days
As Required
4/Yr.
Before Use
n/r
6 Mo.
Minimal
Monthly
Given
Daily
n/r
6 Mo.
Calibration
Procedures
None
n/a
None
n/a
None
None
None
None
None
Gas Std.
n/r
Automatic
Std. Gas
Day/Month
Zero/Span
Daily
n/r
Automatic
Calibration
Schedule
n/a
n/a
None
n/a
None
None
None
None
None
Before Use
n/r
1/Hr.
Var.
Day/Month
Daily
Daily
n/r
1/Day
Flow
Rate
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
0.010L/min.
n/r
n/a
Var.
0.5-1.5
L/min.
0.3-0.6
L/min.
0.05-0.5
L/min.
n/r
n/a
Certification
No
n/a
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Use Stds.
Use Stds.
Use Stds.
Calibr.
Yes
Use Stds.
No
Use Stds.
Given
Differentiates
Surface Vs.
Underground
No
n/a
No
No
No
No
No
No
n/a
Yes
By Placement
No
No
No
Yes
No
By Placement
No
C-17
-------
Table C-6
Vendor Responses For Recommended
Procedures For Leak Monitoring Devices (Continued)
Type of
Detector/ Maintenance Maintenance
Company Requirements Schedule
Continuous Gas-Phase
Catalytic Sensor Devices
Bacharach Std. Gas n/r
Instrument Co.
Industrial Calibration None
Scientific
Devices
Intek Corp. Calibration Var.
Rexnord Gas Calibration 4/Yr.
Detection Prods.
Diffusion Sensors
Adsistor None None
Technology
Emco Annual Test Annual
Wheaton
EMMCO Self testing Self Testing
Enterprises
Spearhead Given 4/Yr.
Tech., Inc.
Metal Oxide Semiconductors
Armstrong None Not Needed
Monitoring
AzonicTech. Clean 1-2/Yr.
Corp.
Calibrated n/r n/r
Instrument, Inc.
Genelco, Inc. 6 Mo. 6 Mo.
MSA None n/a
Universal Not Given 4/Yr.
Sensors & Devices, Inc.
U.S. Industrial Minimal 6 Mo.
Products Co.
Product Permeable Devices
Teledyne n/r n/r
Geotech
Calibration
Procedures
n/r
Std. Gas
Var.
See
Manual
Yes
None
Resistance
Test
Given
Gas Std.
See Manual
n/r
Self-
Calibration
See
Manual
None
6 Mo.
n/r
Calibration
Schedule
Check
Before Use
Check
Before Use
n/r
4/Yr.
Once
n/a
Not
Established
Given
When Sens.
Replaced
During
Maintenance
n/r
None
4/Yr.
None
At Install.
n/r
Flow
Rate
>1.2SCFH
n/a
1 L/min.
(+/- 50%)
2 Ft3/Hr.
n/a
n/a
n/a
n/a
n/a
2 L/min.
n/r
2 L/min.
n/a
n/a
n/a
0.7-1.1
L/min.
Differentiates
Surface Vs.
Certification Underground
Cert. Gas No
n/r n/a
Zero/Span n/r
Yes No
Yes By Location
Yes No
Yes No
Given Given
Cal-kits No
Yes Yes
n/r n/r
Yes Yes
n/a No
Yes n/a
n/a n/a
n/r n/r
C-18
-------
GLOSSARY OF TERMS
The purpose of this section is to provide definitions related to proper interpretations of this report.
Accuracy is the degree of agreement between the
measured value and the "true" value; it includes
components of bias (systematic error) and
precision (random error).
Anode is the electrode at which oxidation (electron
releasing) reactions occur. The anode is
electrically connected to a cathode (see
definition) where the released electrons are
consumed. In the process of corrosion, the anode
is the place where metal oxidizes to positive ions
which dissolve in the electrolyte. The anode may
be a separate piece of metai, as when steel is
connected to brass (see galvanic corrosion), or it
may be an area on a freely corroding surface
which develops a slight positive potential relative
to the rest of the metal because of metallurgical or
environmental variations. Metal is eaten away at
this location. Anodes in impressed current
cathodic protection systems are not necessarily
metallic, but must be electrical conductors.
Annular space is the space between the inner and
outer walls of a double-wall tank or pipe.
Aquifer refers to subsurface strata containing
sufficient groundwater so that the water can be
pumped out.
Area-wide surveillance techniques refer to a
number of methods used to identify the location of
a leak or to delineate an area of contamination.
They involve systematically making a number of
measurements over a large area.
Automatic level sensor refers to an instrument used
for inventory control to provide unattended,
product volume measurements.
Background contamination is any residual
concentration of the analyte of interest that may
be present at a site.
Calibration schedule is the frequency of inspection
and adjustments required to ensure reliable
detector performance.
Cathode is an electrode where reduction (electron
consuming) reactions occur. No corrosion (metal
loss) occurs at cathodes.
Cathodic protection is a technique for reducing the
rate of corrosion of a metal by artificially making it
the cathode of an electrochemical corrosion cell
by application of direct current. There are two
fundamental kinds of cathodic protection systems:
sacrificial anode systems and impressed current
systems. Sacrificial anode systems consist of
anodes of active metals like zinc, magnesium, or
aluminum connected to the structure to be
protected. The active metal corrodes away and
releases electrons into the structure to be
protected; in this way, the structure becomes a
cathode. The anodes which are consumed over
time are "sacrificial" and must be replaced
periodically. Impressed current systems use DC
current from an external power supply. The
anodes are inert, do not corrode away, and do not
require periodic replacement.
Chemical Indicators are leak detection methods that
use test materials that produce a color change
when exposed to a particular product.
Coatings are corrosion and chemical resistant
materials that are sprayed, brushed, or rolled onto
the metal surface of a storage tank. Coatings
serve one of two main purposes: (1) they protect
the metal from attack by a corrosive liquid or
environment, or (2) they protect the product from
contamination by corrosion products.
Continuous monitoring systems are leak detection
systems that provide automatic, unattended leak
monitoring over extended periods of time. The
sampling frequency typically involves multiple
measurements per hour.
Control box life is the anticipated usable time period
for the control box of a leak detection system.
Corrosion is the degradation of a material by its
environment. In the context of this report, most
G-1
-------
corrosion is electrochemical. (See corrosion
cell.)
Corrosion cell, also called an electrochemical cell,
consists of (1) a metallic anode where oxidation of
metal to positive ions occurs; these positive ions
detach from the metal entering the electrolyte,
and this results in metal loss; (2) a cathode where
reduction reactions consume the electrons
generated by the oxidation reaction at the anode;
(3) an electrical conductor between the anode and
cathode; and (4) an electrolyte wetting both anode
and cathode. All of these components must be
present for corrosion of buried structures to occur.
Costs refer to the price of purchasing, installing, and
maintaining a leak detection system.
Data capture is the percentage of valid measure-
ments retained.
Detection limit is the minimum amount or
concentration of a substance (pollutant) that can
be identified, measured, and reported with 99
percent confidence that the analyte concentration
is greater than zero. It is determined from
analysis of a sample in a given matrix containing
the analyte.
Dielectric constant is a value that serves as an index
of the ability of a substance to resist the
transmission of an electrostatic force from one
charged body to another. The lower the value, the
greater the resistance.
Double-wall pipe refers to two pipes in one (i.e., a
complete pipe enclosed within a secondary pipe).
These are typically provided with a means for
monitoring the space between the inner and outer
pipes for a leak in either pipe.
Double-wall tank refers to two tanks in one (i.e., a
complete tank enclosed within a secondary tank).
These are typically provided with a means for
monitoring the space between the outer and inner
tanks (called the annulus) for a leak in either tank.
Drift is the change in baseline readings with time
because of internal electronic variations.
Electrolyte is any medium containing mobile ions
which can conduct a current. Soil moisture and
groundwaters are the electrolytes of concern with
buried underground tanks.
Electrolytic corrosion (see also stray current
corrosion) is electrochemical corrosion as a
result of impressed electrical currents from
sources other than the intended circuit. These
"stray currents" impress a negative potential,
relative to the electrolyte, on some areas of the
affected structure. These areas are cathodically
protected. Other areas develop impressed
positive (anodic) potentials, become anodes, and
suffer accelerated corrosion. Sources of stray
currents may be cathodic protection systems of
surrounding facilities, factories or shops using DC
current equipment (i.e., arch welders), electrified
railways or transit systems, and buried utility
power cables. Improper grounding of electric
equipment connected to the buried structure may
also cause stray current corrosion.
Electrical Insulation is a material which does not
conduct electrons. Placing an electric insulator
between two dissimilar metals will prevent
galvanic corrosion.
Electrical resistivity sensors are leak detection
cables that deteriorate in the presence of
petroleum product. This causes a change in an
electrical signal, thereby activating an alarm.
EMSL (Environmental Monitoring Systems
Laboratory) is the part of the U.S. Environmental
Protection Agency responsible for developing the
technical background necessary for developing
regulations for leak monitoring.
Fall time is the time required for the detector to return
to a near-baseline reading after the pollutant is no
longer present.
FRP (fiber-reinforced plastic) is a composite
material made up of a resin (typically epoxy or
polyester) reinforced with fibers. Spun glass in
strands or woven mats is the usual reinforcing
material. FRP does not corrode by
electrochemical process and is unaffected by
groundwater. FRP is widely used for corrosion-
resistant pipe and tanks. It can be severely
degraded by some commercial products which
may be stored in underground storage tanks.
Galvanic corrosion occurs when dissimilar metals,
such as steel and brass, are electrically connected
together and are placed in the soil electrolyte.
One of the two metals, steel in the above
example, becomes an anode and corrodes at an
accelerated rate, especially when it is adjacent to
the other metal. Galvanic corrosion can be
prevented by using special isolation fittings to
join the two materials.
Geotextile is a textile fabric, such as a filter fabric
used in civil engineering applications. It is used in
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conjunction with synthetic liners to provide
structural support.
Grab sampling is the collection of discrete soil, water,
or gas samples from a given area for analysis.
Ground water is the water beneath the ground surface
that fills the cracks and pore spaces of rocks or
soils.
Groundwater masking occurs when a leak is present
but is not detected by integrity testing because the
hydrostatic pressure outside the tank equals the
head pressure inside the tank, and no net fluid
level changes occur.
Henry's Law states that the amount of a gas that
dissolves in a given quantity of a liquid at constant
temperature is directly proportional to the partial
pressure of the gas above the solution.
Henry's Law constant is the compound-specific
proportionality constant in Henry's Law equations.
Inclined tank refers to an underground storage tank
that is not level. Therefore, the manufacturer's
product level versus tank volume charts are not
accurate.
Instrument response time is the time required for the
instrument to register 95 percent of the final
reading (true value) once the detector comes in
contact with the substance of interest.
Integrity testing refers to in-tank procedures used to
determine if an underground storage tank system
is leaking. These tests typically involve shutting
down the facility for up to a day and temporarily
installing specialized test equipment. They
provide a point-in-time determination of whether
the system is leaking.
Interface probes are leak detectors that utilize both
fiber optics to identify liquid levels in a monitoring
well and conductivity probes to differentiate
between oil and water.
Interferences are any chemical substances or
physical phenomena that hinder the performance
of the leak detection system.
Interior liner is a corrosion and chemical resistant
material which is sprayed, brushed, or applied
onto the interior of a tank. This protects the metal
from attack from corrosive liquids or environments
and protects the product from contamination by
corrosion products.
Intermittent monitoring systems refers to the
manual, periodic sampling of observation wells for
leak detection.
Interstitial monitor refers to a leak detector used in
the annular space of a double-walled tank or pipe.
Intrinsic safety is the ability of monitoring a device to
operate safely in recommended operating
environments. Also, it is the acceptability of any
safety-related information printed on the device
and in the operating manual.
Inventory control refers to measurements and record
keeping designed to track all transfers of product
into and out of a storage tank. An imbalance or
discrepancy between measured levels and the
delivery and use receipts may indicate that a leak
is present.
Isolation fitting is a device for connecting pipes of
dissimilar metals together without an electrical
connection, and thus, for preventing galvanic
corrosion. For smaller pipe sizes, the device
consists of a specially designed "isolation union"
with an insulator insert. Special gaskets are
available for flanged connections. Great care is
required to be sure that there is no alternate
conductor path around the isolation fitting, or no
benefit will occur from its use.
Lag time and rise time when summed are the total
length of time for an alarm to be activated once
the sensor comes in contact with the analyte at a
level above the detection limit. For electronic
devices, lag time is the time for a discernible
signal to be generated once the monitor comes in
contact with the specie of interest. Rise time is
the time from when a discernible signal is
generated until an alarm level (or 95 percent of the
final reading) is reached.
Leak detection refers to any approach used to
determine whether an underground tank is tight
(not leaking); it includes integrity testing, inventory
control, and leak monitoring.
Leak monitoring refers to the examination of the area
outside the tank for evidence of free product.
Liner refers to synthetic or natural (e.g., clay)
materials used to cover the bottom and sides of
the excavation pit to serve as secondary or tertiary
containment.
Llthology is the character of a rock formation.
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LUST (Leaking Underground Storage Tanks) is an
acronym frequently used as a catch-all term to
describe topics related to underground storage
tanks.
Maintenance schedule is the frequency of inspection
and repair required to maintain reliable system
performance.
Monitoring refers to all procedures used to
systematically inspect and collect data on
operational parameters.
Monitoring well is a well that extends from surface
grade to several feet below the water table (or
several feet below the tank bottom in arid areas)
and that permits leak detection devices to sense
the subsurface environment.
Noise refers to any background or signal
interferences.
Operating environment is the range of environmental
and operating conditions (e.g., temperature, pH,
line voltage) that a leak monitoring device will
experience during its usable life.
OUST (Office of Underground Storage Tanks) is
the part of the U.S. Environmental Protection
Agency established to oversee the regulatory
effort for underground storage tanks.
Overfill protection refers to the use of liquid level
alarms or automatic shut-off valves to prevent
excess product from being delivered to a tank; as
well as to impermeable barriers, sorbents, and
special couplings designed to minimize and
contain spilled product at transfer areas.
Permeability is the capacity of a porous medium to
conduct or transmit fluids.
Pitting is a particularly damaging form of corrosion in
which small areas of the metal surface corrode
rapidly to form cavities or holes. The overall
corrosion rate may be low while penetration of the
tank wall occurs rapidly in a few isolated areas.
Unprotected buried steel does pit rapidly under
certain soil conditions.
Porosity is the ratio of the volume of interstices of a
material to the volume of its mass.
Precision is the measure of the ability to make
replicate measurements, i.e., an estimate of
random error.
Product refers to any material stored in an
underground tank. In this report, product is
typically assumed to be petroleum in some form,
such as gasoline, fuel oil, or diesei fuel, etc.
Product permeable devices are leak detectors that
allow volatile petroleum product vapors, but not
water vapor, to pass through a coated surface to a
sensing element.
Product soluble devices are leak detectors that
contain a polymer that dissolves in petroleum
product but not in water. This dissolution can be
used to trigger an alarm by any one of several
designs.
Qualitative Integrity test is an integrity test that
determines if an underground storage tank system
is leaking but that does not specify a leak rate.
Quantitative Integrity test is an integrity test that
determines whether or not an underground
storage tank system is leaking and that provides a
leak rate.
RCRA (Resource Conservation and Recovery Act)
is the law in which Congress has required
regulation of most underground storage tanks
containing petroleum products.
Recommended operating environment is the
vendor's estimated working range for its system
with regard to temperature, humidity, etc. (see
also operating environment).
Response time is the instrument response time plus
the time for any leaked product to reach the
sensor (see also instrument response time).
Sacrificial protection is the minimization or
prevention of corrosion of a metal in an electrolyte
by galvanicaily coupling it to a more anodic metal
that literally is consumed; hence, sacrificial.
Sampling frequency is the number of sampling
events per unit time.
Secondary containment refers to a system installed
so that any volume of leaked material from the
primary containment is prevented from reaching
the soil or water outside the containment for the
anticipated period of time necessary to detect and
recover the leaked material.
Sensor life is the anticipated reliable time period for
the sensing element of a leak monitoring system.
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Service life is the expected useful life of the control
box, sensors, and ancillary equipment.
Sheen is an iridescent appearance on the surface of
water.
Signal/noise is the ratio of a discernible measured
value to the normal signal output when no sample
is present.
Specificity is the ability of a monitor to detect a
specific chemical or class of chemicals.
Stray current corrosion is corrosion resulting from
direct current flow-through paths other than the
extended circuit. Service stations, for example,
built near cathodic protection rectifiers, factories or
shops using DC, or electrified (P.C.) railways or
transit systems may experience stray current
corrosion.
Synthetic liner is a plastic or rubber sheeting used to
line an excavated area.
Tank-end deflection refers to the outward movement
of the ends of a steel storage tank when product is
added to the tank. The term may also be used to
refer to the bowing out of the sides of a fiberglass
tank after filling.
Thermal conductivity sensors are floating leak
detection probes that measure heat loss at the air-
liquid interface in a monitoring well. They
distinguish between air, water, and product.
Threshold detection is the lower limit of detector
sensitivity.
U-tube refers to a collection system for leaked product
that can be used to underlie a storage tank in
areas with deep groundwater. The U-tube permits
liquid-phase leak detection methods to be
employed.
Underground storage tank (UST) systems refer to
tanks buried underground and to the related
system composed of product lines, pumps,
dispensers, and associated appurtenances for the
storage and dispensing of light petroleum
products. Any storage system with 10 percent or
more of its volume below ground is considered an
UST system.
Vapor pockets are small volumes of volatilized
product that may accumulate against the upper
surface of a tank and that may affect integrity test
results.
Vapor pressure is the pressure characteristic at any
given temperature of a vapor in equilibrium with its
liquid or solid form.
Viscosity Is the property of a fluid that enables it to
develop and maintain an amount of shearing
stress dependent on the velocity of flow and then
to offer continued resistance to flow.
Water table refers to a layer beneath the ground
where the rocks or soil are saturated; it separates
the phreatic zone (below) from the vadose zone
(above).
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