ASTM E2733-23

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2733 − 10 (Reapproved 2015) E2733 − 23
Standard Guide for
Investigation of Equipment Problems and Releases for
Petroleum the Source and Cause of Releases from
Underground Storage Tank Systems
This standard is issued under the fixed designation E2733; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This guide provides a framework for the development of procedures and directions for the
investigation of equipment problems associated with petroleum underground storage tank (UST)
systems and releases. underground storage tank (UST) equipment problems and the source and cause
of releases. Source and cause investigations are similar to origin and cause investigations in property
insurance claims. It gives the user practical suggestions of how to investigate equipment and
installation problems, document findings, and in some cases prepare samples of collect and preserve
failed equipment for laboratory analysis. forensic evaluation or laboratory analysis if necessary, and
implement visual and analytical processes to document the source of a release. Use of this guide may
result in the identification of equipment and installation problems that can be corrected in future tank
system designs and equipment maintenance programs to prevent releases to the environment. Use of
this guide may assist regulatory agencies to determine and document the source and cause of releases
from UST systems.
1. Scope
1.1 Overview—This guide is an organized collection of information and series of options for industry, regulators, consultants and
the public, intended to assist with the development of investigation protocols for underground storage tank facilities in the United
States. While the guide does not recommend a specific course of action, it establishes an investigation framework, and it provides
a series of techniques that may be employed to: identify equipment problems; in some cases prepare samples ofcollect and preserve
failed equipment for laboratory analysis; forensic evaluation or laboratory analysis; identify the source of a release; and document
the investigation. The guide includes information on methods of investigation, documentation, taking samples of problem
equipment; preservation of equipment collecting and preserving samples; chain of custody; storage; shipping; working with
equipment manufacturers; and notification of regulators and listing laboratories. The goal in using the guide is to identify the
appropriate level of investigation and to gather and preserve information, in an organized manner, which could be used in the future
to improve system design or performance. While this guide may act as a starting point for users with limited experience in failure
investigation, the user is encouraged to consult with failure analysis experts for specific investigation procedures that may be
needed for certain equipment and the investigation should be conducted by a qualified professional. As users develop their specific
investigation protocols, they may find that the investigations can be streamlined for certain types of facilities.
1.2 Limitations of This Guide:
This guide is under the jurisdiction of ASTM Committee E50 on Environmental Assessment, Risk Management and Corrective Action and is the direct responsibility
of Subcommittee E50.01 on Storage Tanks.
Current edition approved April 1, 2015Sept. 1, 2023. Published May 2015October 2023. Originally approved in 2010. Last previous edition approved 2015 as
E2733–10(2015). DOI: 10.1520/E2733–10R15.10.1520/E2733–23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2733 − 23
1.2.1 Given the variability of the different investigators that may wish to use this guide and the different types of facilities and
failures that will be investigated, it is not possible to address all the relevant standards that might apply to a particular investigation.
This guide uses generalized language and examples to guide the user. If it is not clear to the user how to apply standards to their
specific circumstances, it is recommended that users seek assistance from qualified professionals.
1.2.2 This guide does not address safety issues associated with the investigation, taking samples and storing equipment. usersUsers
are cautioned to exercise proper care in handling equipment that was in contact with flammable and combustible liquids and
vapors. Some of the activities described in this guide may be subject to OSHA (Occupational Safety and Health Administration)
regulations or may only be conducted by individuals with appropriate HAZWOPER (Hazardous Waste Operations and Emergency
Response) training certifications recognized by federal and state regulatory authorities, such as HAZWOPER training.
1.2.3 This guide does not address laboratory investigations of material properties and detailed failure analysis.
1.2.4 This guide does not cover underground storage tank systems storing liquefied petroleum gas (LPG).
1.2.5 This guide does not replace state-required closure assessments and investigations. Requirements vary from state to state and
often include specific sampling requirements. The user should comply with the requirement of the authority having jurisdiction.
1.2.6 Prior to implementing the steps described in Section 5, users of this guide must determine if the authority having jurisdiction
has any qualification requirements for the individual performing the investigation.
1.2.7 Investigations addressed by this guide may involve knowledge, skills, and abilities generally attributed to individuals
certified as tank systems installers, inspectors, or removers, or those who are trained in soil and groundwater sampling protocols
(for example, geologists, groundwater professionals, or engineers).
1.3 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this
standard.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E1188 Practice for Collection and Preservation of Information and Physical Items by a Technical Investigator
E1990 Guide for Performing Evaluations of Underground Storage Tank Systems for Operational Conformance with 40 CFR,
Part 280 Regulations
E2681 Guide for Environmental Management of Underground Storage Tank Systems Storing Regulated Substances
F1127 Guide for Containment of Hazardous Material Spills by Emergency Response Personnel
2.2 Other Standards:
STD 2015 Requirements for Safe Entry and Cleaning of Petroleum Storage Tanks, 6th Edition—August 2001
RP 2016 Guidelines and Procedures for Entering and Cleaning Petroleum Storage Tanks, 1st Edition—August 2001
PEI/RP 100 Recommended Practices for Installation of Underground Liquid Petroleum Storage Systems, Petroleum Equipment
Institute (PEI)Systems
PEI/RP 1700 Tank Closure and Removal
NFPA 30 Flammable and Combustible Liquids Code
2.3 Federal Regulations:
49 CFR 172§49 CFR §172 Hazardous Materials Table, Special Provisions, Hazardous Materials Communications, Emergency
Response Information, and Training Requirements
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Petroleum Institute (API), 1220 L. St., NW, Washington, DC 20005-4070, http://www.api.org.
Available from Petroleum Equipment Institute (PEI), P. O. Box 2380, Tulsa, OK 74101-2380, http://www.pei.org.
Available from National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02169-7471, http://www.nfpa.org.
Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
www.access.gpo.gov.
E2733 − 23
29 CFR 1910.146§29 CFR §1910.146 Occupational Safety and Health Standards, Subpart J, General Environmental Controls,
Permit-required Confined Spaces
3. Terminology
3.1 Definitions:
3.1.1 compromised, adj—a loss of structural integrity or diminished ability to perform as designed.
3.1.2 equipment problems or problem equipment—equipment, n—any failure, malfunction, compromised condition or other issue
that has resulted in impairment, abnormal equipment condition or operation or that has resulted in a release or suspected release.
3.1.3 free product, n—a regulated substance that is present as a nonaqueous phase liquid (for example, liquid not dissolved in
water).
3.1.4 release, v—any spilling, leaking, emitting, discharging, escaping, leaching or disposing from an UST into groundwater,
surface water or subsurface soils.
3.1.5 release prevention—prevention, n—activities that reduce the risk of human and environmental exposure to petroleum or
hazardous substances. In the United States, underground storage tank and toxic use reduction regulations are examples of such
requirements.
3.1.6 regulated substance, n—Any substance defined in section 101(14) of the Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA) of 1980 (but not including any substance regulated as a hazardous waste under subtitle
C); and Petroleum, including crude oil or any fraction thereof that is liquid at standard conditions of temperature and pressure (60
degrees Fahrenheit and 14.7 pounds per square inch absolute).
3.1.6.1 Discussion—
The term regulated substance includes but is not limited to petroleum and petroleum-based substances comprised of a complex
blend of hydrocarbons, such as motor fuels, jet fuels, distillate fuel oils, residual fuel oils, lubricants, petroleum solvents, and used
oils.
3.1.7 tightness test, n—a procedure capable of detecting a 0.1 gallon per hour leak rate from any portion of the tank that routinely
contains product while accounting for the effects of thermal expansion or contraction of the product, vapor pockets, tank
deformation, evaporation or condensation, and the location of the water table.
3.1.7.1 line tightness test, n—A periodic test of piping that can detect a 0.1 gallon per hour leak rate at one and one-half times
the operating pressure.
3.1.7.2 tank tightness test—includes a wide variety of test methods that must be able to detect a leak at least as small as 0.1
gallon per hour with certain probabilities of detection and of false alarm.
3.1.8 underground storage tank—tank, n—a tank and any underground piping connected to the tank that has at least 10 % of its
combined volume underground.
3.1.9 waste—discarded solid or liquid materials that may be hazardous to public health or the environment. Solid and hazardous
waste require controls on handling, transport, storage treatment, and disposal.
4. Significance and Use
4.1 This guide may be used in the investigation of underground storage tank systems for equipment problems in a wide variety
of applications. Use of this guide is voluntary. It is intended to assist users who want to investigate equipment failures and
malfunctions. failures, malfunctions, and other potential causes of suspected releases.
4.2 The following groups of users may find the guide particularly helpful:
4.2.1 Storage tank system designers;designers and manufacturers;
4.2.2 Storage tank installers;installers, testers, and inspectors;
E2733 − 23
4.2.3 Storage tank maintenance contractors;
4.2.4 Storage tank removal contractors;
4.2.5 Storage tank inspectors;
4.2.5 Federal, state state, tribal or local regulators, including departments of health, departments of environmental protection, and
fire departments;
4.2.7 Storage tank release detection installers;
4.2.8 Storage tank testers;
4.2.6 Petroleum release remediation consultants;professionals;
4.2.10 Storage tank equipment manufacturers;
4.2.7 Insurance adjusters;
4.2.8 Storage tank owners and operators;
4.2.12.1 Retail fuel service station owners and operators;
4.2.12.2 Small businesses or enterprises;
4.2.12.3 Service industries;
4.2.12.4 Waste managers, including liquid and solid waste haulers, treatment, recycling, disposal and transfer;
4.2.12.5 Non-regulatory government agencies, such as the military;
4.2.12.6 Specific industrial sectors such as dry cleaners, printers, photo processors, laboratories; and
4.2.9 Consultants, auditors, inspectors, and compliance assistance personnel.
4.3 This guide is intended to assist in the development of protocols for determination of source and cause of a release and the
investigation of a malfunction or failure of storage tank systems any component of a UST system and the implementation of said
protocols. This guide outlines steps that may be necessary and include, but are not limited to initial evaluation of the UST system
to determine the malfunction(s); if there has been a component failure preparation of samples of failed or compromised equipment
for laboratory analysis; and document visual; and analytical evaluation of release indications; and documentation of the
investigation. The guide provides a series of investigation options onfrom which the user may design failure investigation
protocols. The guide describes common investigation techniques in the order in which they might be employed in an investigation.
4.4 A user may elect to utilize this guide for a number of reasons, which include, but are not limited to:
4.4.1 To differentiate new releases from new discovery of old releases;
4.4.2 To establish malfunction and failure rates of various storage tank equipment UST system components;
4.4.3 To determine expected life spans of various storage tank equipment UST components;
4.4.4 To identify opportunities for improving the performance and reliability of storage tank equipment;
4.4.5 To focus inspection and maintenance efforts on those portionscomponent of the tankUST system that are most prone to
compromise, malfunction and failure;
4.4.6 To identify those components of the storage tank UST system that require more frequent maintenance;
E2733 − 23
4.4.7 To reduce remediation and equipment replacement costs;
4.4.8 To prevent petroleum releases;
4.4.9 To identify those conditions that may cause or contribute to the equipment or component compromise, deterioration or other
cause the malfunction and failure of various components of of malfunction or failure of the UST system; and
4.4.10 To comply with environmental regulations that require the investigation of release detection alarms and the source of
releases.suspected releases and determine the source and cause of releases; and
4.4.11 To identify conditions that may cause or contribute to nonsudden releases that may not be detected by other leak detection
methods.
4.5 This guide may be used to establish a framework, whichframework that pulls together the common approaches to
investigation. The framework will allow the user to establish an investigation protocol to meet their the user’s specific
requirements. Specific user requirements will vary depending upon the purposes of the data collection and the decisions that the
investigation is intended to support. This guide does not provide methods to establish specific user investigation requirements nor
does it establish minimum levels of documentation.
4.6 This guide will acquaint users with methods and tools that may be used in investigations of equipment problems associated
with USTs. The user may include a subset of the methods described in this guide in their investigation. The user may consider a
variety of factors in determining which combination of the methods to employ.
4.7 This guide is not intended to require the user to conduct a failure investigation.
4.8 This guide is focused on the identification, documentation, and preservation of underground storage tank system equipment
problems. compromised UST system equipment. It does not provide guidance on establishing root causes of compromise,
malfunction or failure. The identification of root causes of compromise, malfunction or failure may require further expert analysis
of the data and equipment collected during the failure investigation.
4.9 Determination of equipment failures and evidence of the source and cause of a release are often unavailable due to the loss
of critical information necessary to pinpoint equipment failures and conduct an investigation. Adjustment, repair or removal of
failed equipment before determining and documenting the cause of the failure may interfere with the failure investigation. Failures
may be caused by compatibility issues, manufacturer defects, corrosion, degradation, improper installation, damage, age, misuse,
use or other causes. This guide may be used to identify techniques and procedures applicable to maintenance personnel and
equipment vendors that will allow an investigator to evaluate possible equipment failures before equipment is adjusted, repaired,
replaced or destroyed.
4.10 This guide does not address all the safety measures that must be taken when removing and disassembling underground
storage tank UST systems. Because most underground storage tank UST systems have contained flammable or combustible liquids
special precautions should be taken to prevent fire, explosions and exposure to toxic vapors. API standard STD 2015 and RP 2016
address some of the safety considerations as do many of the procedures available from fire departments.
5. Elements of Failure Investigation
5.1 Failure Investigation Process—The guide will acquaint users with methods and tools that may be used in investigations of
equipment problems associated with petroleum underground storage tanks and releases. The user may include a subset of the
methods described in this guide in their investigation. The user may consider a variety of factors in determining which combination
of the methods to employ. For example, the manner of discovering a manner of discovering equipment problems or evidence of
a release may influence the methods employed. If there is an indication of a release from release detection or off site impacts, the
user may select failure investigation methods that rely on records reviews and non-destructive tests. If the release is discovered
during tank removal, some equipment tests may not be possible, and the user may choose visual examination techniques. If there
are no indications of a release, the user may choose to employ visual examination techniques to check on the site assessment
E2733 − 23
information that indicated that no release occurred. investigation methods employed. The qualifications of the investigator may
depend upon whether the investigation occurs while the system is still operational or during system closure. Investigator
qualifications are addressed in 5.18.
5.1.1 For all investigations, knowledge of the tank system obtained through review of 5.2 General Records is recommended.
Knowledge of the age, material, and construction of the system prior to investigation will allow for a more focused investigation
by an appropriately qualified investigator.
5.1.2 Suspected Releases from Operational Systems. If there is an indication of a release from unusual operating concerns such
as inventory loss, failed or inconclusive leak detection or tightness tests, or receptor impacts, the user may select failure
investigation methods that initially rely on records reviews and non-destructive tests identified in 5.3 Release Detection Records,
and 5.4 Release Preventions Records. See Fig. 1.
5.1.2.1 . If release detection records are inconclusive or indicate a the release has occurred, 5.6.4 tightness testing may identify
a tank or piping run as the source.
5.1.2.2 If tightness tests do not confirm a release, proceed with the inspection techniques of 5.5 and 5.6.
5.1.2.3 If a tank or piping run fails leak detection or a tightness test, the system should be shut down and the investigator should
proceed with the investigation techniques of 5.7 and 5.8.
5.1.2.4 If release detection records and release prevention records do not indicate a release, proceed with the inspection techniques
of 5.5 and 5.6.
5.1.2.5 If there is an indication of a release based upon a visually identified equipment leak or damaged component, proceed with
the investigation techniques of 5.5 and 5.6. While continuous operation or return to normal operation may be a priority when an
equipment problem is suspected, any condition that may be the source of a release should be investigated with the potential
equipment failure fully documented before any equipment is adjusted, repaired or removed. If a release is suspected, maintenance
personnel or service companies should not be allowed to adjust, repair or remove failed equipment without approval from the
investigator.
5.1.3 System closure. Many releases discovered during system closure are the result of nonsudden releases which may not be
identified by leak detection records, release prevention records or other investigative techniques. Tank and piping closures result
in the discovery of a significant number of previously unidentified releases. Investigators should be prepared to conduct suspected
release investigations during closure activities. Advance review of records identified in 5.5, 5.6 and 5.7 will prepare the investigator
for possible indications of a release during closure activities. If a release is suspected during tank or piping closure, some
equipment tests may not be possible, and the user may choose other visual examination techniques identified in 5.7.
5.1.3.1 If there is an indication of a release, the investigation techniques of 5.8 may be applicable.
5.1.3.2 If the review of records in 5.5 and 5.6 do not provide indications of a release, the user may choose to employ visual
examination techniques in 5.7 and field screening techniques from 5.8 to determine if there are indications of soil or groundwater
(if encountered) contamination associated with specific components of the tank system. If closure sampling requirements of the
authority having jurisdiction do not indicate a release has occurred, no further investigation is required.
5.2 General Records—Gathering and reviewing records prior to the physical investigation may help focus the investigation and
make the investigation run smoothly. Reviewing records from the following categories may help inform the user what types of
equipment to expect, where the equipment can be found, the repair and maintenance history and prior releases. These records may
be in the possession of the owner(s) of the petroleum underground storage tank system; a third party consultant or maintenance
contractor; or one or more regulatory entities. The user may find that it is beneficial to organize the records and bring them to the
field investigation for reference. Installation, repair, maintenance and testing records should be retained in accordance with the
guidance in Guides E1990 and E2681.
5.2.1 Equipment purchase records.
5.2.2 Installation records:
5.2.2.1 “Record” or “as-built” drawings andor site plans;
E2733 − 23
FIG. 1 Failure Investigation of Suspected Release
E2733 − 23
5.2.2.2 Installation check lists;
5.2.2.3 Pre-operation leak checks;
5.2.2.4 Regulatory registration data;
5.2.2.5 Warranty registration data; and
5.2.2.6 Photos and videos of the original installation.
5.2.2 Operating and Maintenance Manuals—Some equipment manufacturers make copies of operation and maintenance manuals
available in printed or electronic form. The user can check the manufacturers’ web sites for ordering or downloading manuals.
Installation records:
5.2.2.1 “Record” or “as-built” drawings and /or site plans;
5.2.2.2 Installation check lists;
5.2.2.3 Pre-operation leak checks;
5.2.2.4 Regulatory registration data;
5.2.2.5 Warranty registration data;
5.2.2.6 Photos and videos of the original installation;
5.2.2.7 Compatibility records for all products stored; and
5.2.2.8 Operating and Maintenance Manuals—Some equipment manufacturers make copies of operation and maintenance
manuals available in printed or electronic form. The user can check the manufacturers’ web sites for ordering or downloading
manuals.
5.2.4 Repair records;
5.2.5 Inventory control records;
5.2.6 Release detection records;
5.2.7 Equipment alarm histories;
5.2.8 Tightness testing records; and
5.2.9 Prior monitoring well, site assessment and remediation records.
5.3 Release detection records. Regulated UST systems in the United States are required to perform monthly release detection that
is able to detect a release from any portion of the tank or piping that routinely contains product. There are several possible methods
of release detection with specific record keeping requirements. Review of release detection records may assist to identify a
suspected release. Release detection alarms may indicate that a system is leaking. They can also indicate that the release detection
equipment is malfunctioning. Some state regulations require that the owner or operator determine the source of a suspected release
following a release detection alarm. In addition to required release detection records, other operational records may assist to
identify a suspected release:
5.3.1 Inventory control records. Inventory records may indicate if there is a significant loss in one or more stored products.
Inventory records are often not accurate and should not be relied upon alone to indicate that a release did or did not occur. Inventory
records should be compared to delivery records, dispensing records and leak detection records;
5.3.2 Delivery records including invoices;
E2733 − 23
5.3.3 Dispensing or sales records;
5.3.4 Equipment alarm histories;
5.3.5 Tank and piping tightness testing records. Tightness testing may detect breaches in the underground storage tank system. A
variety of methods are available with various degrees of accuracy and sensitivity. Tightness tests are generally divided into two
categories: volumetric and non-volumetric. Some tightness testing methods detect breaches in specific portions of the underground
storage tank system. The user should consider the characteristics of the tightness test when selecting a test method and evaluating
the results of the test.
5.3.5.1 Volumetric tests apply pressure to the system and measure for an change in volume over time. Each test has requirements
for the amount of fuel that must be in the system to obtain a valid test.
5.3.5.2 Non-volumetric tests use other methods to determine if the system is leaking. Some methods place a chemical marker or
tracer in the system and then check for the presence of the marker outside the system. Some tracers may be able to permeate
through some materials that are liquid tight and even some materials that are impermeable to most vapor components of motor
fuel. The user should consider the characteristics of the tracer when selecting a test method and evaluating the results of the test.
5.4 Release prevention records. Regulated UST systems in the United States are required to comply with technical regulations that
are designed to prevent releases. The regulations require operation and maintenance activities that must be documented and records
maintained. These records may assist in the investigation if a release is suspected.
5.4.1 Cathodic protection installation, testing and maintenance records
5.4.2 Walkthrough inspection records:
5.4.2.1 30 day walkthrough;
5.4.2.2 Annual walkthrough;
5.4.3 Other periodic testing records:
5.4.3.1 Spill prevention equipment tests;
5.4.3.2 Liquid tight tests of containment sumps used for interstitial monitoring;
5.4.3.3 Leak detection equipment tests:
(1) Automatic tank gauge and other controllers;
(2) Probes and sensors;
(3) Automatic line leak detectors;
(4) Vacuum pumps and pressure gauges; and
(5) Hand-held electronic sampling equipment
5.5 Other records:
5.5.1 Prior monitoring well, site assessment and remediation records
5.5.1.1 An increase in a contaminant of concern may indicate a new release;
5.5.2 Maintenance and service records including any invoices
5.5.2.1 Recent maintenance activities may have disturbed existing components or created an equipment failure;
5.5.3 Inspection records and photos including inspection response documentation;
5.5.4 Repair records including repair invoices
E2733 − 23
5.5.4.1 Recent repairs may have addressed an equipment failure or created a new equipment failure;
5.6 Pinpointing Thethe Source of a Release and Malfunctioning Equipment in an Operating or Undisturbed Tank System:
Identifying Equipment Problems During Excavation, Prior to Equipment Removal—Most releases are not identified by leak
detection methods. Components such as pumps, leak detectors and dispensers may leak and not be detected by traditional leak
detection methods. Evaluation of tank top and dispenser components may identify failed equipment or other sources of leaks.
5.6.1 Dispenser evaluation. Dispensers have been identified as a primary source of leaks. Dispensers and components located
above the shear valve are not included in the definition of a UST system under federal regulations but may be regulated by the
authority having jurisdiction. Dispensers may or may not have under dispenser containment (UDC) and the UDC may or may not
be monitored for releases. Careful observation and photo documentation of the dispenser and connected piping under the dispenser
before the dispenser is disconnected from the UST system and during the disconnection process may reveal improper installation
or component compromise that may contribute to a release.
5.6.2 Tank top and other surface component evaluations. Containment sumps containing piping, pumps, leak detectors and other
equipment may be sources of leaks. Careful observation and photo documentation of sumps, piping and other equipment before
the sumps, piping or equipment are disconnected from the UST system and during the disconnection process may reveal improper
installation or component compromise that may contribute to a release.
5.6.3 Visual—Visual examination—If a release is suspected, maintenance personnel or service companies should not be allowed
to adjust, repair or remove failed equipment without approval from the investigator. Careful observation of the equipment may
reveal misalignment of equipment and malfunctioning or compromised components. While not always the case, generally
underground storage tank UST equipment is installed in alignment and should remain in alignment throughout the life of the
system. Poor alignment of the installed equipment may indicate shifting, settling, creep, expansion expansion, compromise or
failure of components. Installation photos or inspection photos when compared to the current conditions may help determine if the
condition of the underground storage tank UST system has deteriorated. Visual indicators of potential problems in the underground
storage tank system of system components include, but are not limited to:
5.6.3.1 Misalignment;
5.6.3.2 Equipment not performing to original specifications, for example loose, rattling or intermittent operation;
5.6.3.3 Indications of prior repairs;
5.6.3.4 Water intrusion into primary containment;
5.6.3.5 Drips and staining in sumps and beneath dispensers;
5.6.3.6 Stored product, water intrusion, stains and sheens in secondary containment;
5.6.3.7 Dead vegetation and staining of surface soil and pavement; and
5.6.3.8 Unusual system operation (that is,(such as slow discharge of product from pumps), which may indicate a leak or a
component failure in the system.system;
5.6.3.9 Lack of structural integrity including the existence of cracks, holes or physical damage ;
5.6.3.10 Indications of component compromise such as material degradation, corrosion, surface delamination, swelling,
elongation or growth.
5.3.2 Inventory records may indicate if there is a significant loss in one or more stored products. Inventory records are often not
accurate, and should not be relied upon alone to indicate that a release did or did not occur.
5.3.3 Release detection alarms may indicate that a system is leaking. They can also indicate that the release detection equipment
is malfunctioning. Some state regulations require that the owner or operator determine the source of a suspected release following
a release detection alarm.
E2733 − 23
5.3.4 Tightness testing may detect breaches in the underground storage tank system. A variety of methods are available with
various degrees of accuracy and sensitivity. Some tightness testing methods detect breaches in specific portions of the underground
storage tank system. The user should consider the characteristics of the tightness test when selecting a test method and evaluating
the results of the test.
5.3.5 Tracer testing can be conducted using a variety of gases. Some tracers, such as helium can permeate through some materials
that are liquid tight and even some materials that are impermeable to most vapor components of motor fuel. The user should
consider the characteristics of the tracer when selecting a test method and evaluating the results of the test.
5.6.4 Other indicators—Soil and groundwater contamination testing conducted prior to or while removing an underground storage
tank system component may help identify releases and in some cases may indicate the proximitysourceproximity of the release.
It is important to determine if a release is new or old, identify the presence of older releases and to determine if the release came
from the the equipment currently in place or from older equipment that has been removed. Most authorities having jurisdiction
require assessment or testing requirements including specific analytical testing methods to investigate suspected releases and for
proper closure of tanks or piping of a UST system.
5.6.5 If an equipment problem is identified and responsibility for the cause may be disputed it is possible that documentation of
the problem may be necessary. To properly document an equipment failure the investigator may refer to E1188 Practice for
Collection and Preservation of Information and Physical Items by a Technical Investigator.
5.7 Pinpointing the Source of a Release and Identifying Equipment Problems During Excavation, Excavation to Repair or Close,
Prior to Equipment Removal—Careful observation and tests during the removal of underground storage tank systems may yield
valuable information on the proximity of a release, whether the release came from the equipment at the site, and conditions that
may have contributed to equipment failure. The following observations and tests can be conducted during the excavation of
underground storage tank UST equipment:
5.7.1 Soil Staining—Most motor fuelsregulated substances can stain soils and backfill materials when released from an
underground storage tank UST system. In many cases, careful excavation in stained areas will help pinpoint sources of release.
Careful observation, photo documentation, collection and preservation of potentially compromised or improperly installed
equipment near or above staining, may provide valuable information on the source and cause of a release. Soil staining can also
provide a rough indication of how long the released product has been in the ground, although this age indication is highly
dependent on the product released and specific conditions at the location being examined. The soil color change is due, in large
part, to changes in soil redoximorphology and geochemistry from degradation of the fuel. regulated substance. Colors can be
recorded using a standard chart system such as MunselMunsell and stratum colors at the point of the release. Documenting soil
colors away from the point of release can be useful for comparison and to further document the cause of the staining. The user
is cautioned that some soils are naturally mottled and that there are other sources of staining besides releases from underground
storage tank UST systems, thus the user should investigate the source of the stain to determine if in fact it is the result of a release
from the underground storage tank UST system.
5.7.2 Visual Assessment of Equipment—Careful examination of the underground storage tank UST system may help identify
equipment problems.
5.7.2.1 Staining and discoloration may be caused by product releases;
5.7.2.2 Damage such as fractures fractures, fatigue, and breaches;
5.7.2.3 Corrosion; and
5.7.2.4 Material compromise or degradation;
5.7.2.5 Improper alignment.
5.7.2.6 Recent system service or repair work
5.7.2.7 Recent construction and other nearby subsurface utility installation or repair activity.
5.7.3 Backfill Conditions—Improper backfill can lead to many types of equipment failure. Excessive settlement in the backfill can
E2733 − 23
lead to inadequate support for tanks. Signs of settlement and inadequate compaction may be observed during excavation.
Settlement may also result from finer surrounding soil migrating into coarse backfills such as pea stone. Some types of equipment
can be damaged by improper backfill including sharp backfill or backfill that contains trash, clumps of clay or large rocks. Unclean
or varied backfill can lead to accelerated corrosion of metallic components. Backfill that is not adequate when compared to the
equipment manufacturer’s installation requirements may indicate that there is an increased likelihood of failure in the component.
5.7.4 Soap tests can be conducted on piping, tank connections and bungs after they have been exposed. In a soap test the pressure
is raised inside the equipment to be tested and the outside is sprayed with a soap solution. Bubbles forming in the soap solution
may indicate the location of a leak. Users of this guide are cautioned to use safe procedures when introducing pressurized gasses
into an underground tank system that may still contain vapors. Inert gas may be required to safely conduct a soap test on an
underground tank system that has contained petroleum.
5.7.5 Similarly to testing of an operating or undisturbed system, tracer tests can be conducted during and after removal using a
variety of gases. Some tracers permeate through materials that are liquid tight and even some materials that are impermeable to
most vapor components of motor fuel. The user should consider the characteristics of the tracer when selecting a test method and
evaluating the results of the test.
5.7.6 Age of Fuel—Regulated Substance—Releases may not be identified for extended periods of time after the release occurs—In
some cases, the age of the petroleumrelease can be estimated. There are a variety of techniques that can be used on free product,
soil, and groundwater that might be sampled during excavation. Estimating the age of the petroleumrelease may help determine
if more than one release has occurred or if the release occurred prior to a repair or replacement date. One of the techniques,
“fingerprinting” attempts to estimate the age by relating the characteristics of the petroleum in the investigation to known changes
in formulations of fuels, refining practices and additives.Various forensic analysis may be utilized for age dating. Some examples
include gas chromatography and mass spectrometry (GC/MS), high resolution gas chromatographic (HRGC) identification and gas
chromatography with electron capture detector (GC/ECD). The Appendix contains information on various techniques.
5.8 Pinpointing the Source of a Release and Identifying Equipment Problems During and After Equipment Removal— A number
of observations can be made as the underground storage tank system is removed. Many of these are similar to the observations
and tests described in 5.45.7 above. The user may conduct additional observations and tests on equipment as described below, Most
of these observations can be made after the equipment is uncovered and before it is removed from the ground, although some of
the items indicated below, such as 5.5.35.8.3 may be more appropriate after removal.
5.8.1 Soil staining.
5.8.2 Equipment Condition:
5.8.2.1 Staining;
5.8.2.2 Damage;
5.8.2.3 Corrosion;
5.8.2.4 Improper alignment;
5.8.2.5 Loose Ffittingsfittings can be observed as equipment is disassembled;
5.8.2.6 Softening of plastic materials may indicate that strength properties of the equipment have deteriorated. For example, soft
and spongy pipe may indicate chemical attack and weakening; and
5.8.2.7 Excessive microbial growth on system components can indicate deterioration of plastics or rubber materials.
5.8.3 Stored Product Trapped in Secondary Containment—Product can build up in the secondary containment system if the
primary containment is leaking faster than the secondary containment system. This can be detected by creating a small hole in the
secondary containment system with a pocket knife or an awl. In some cases, particularly in certain models of thermoplastic pipe
where the secondary containment pipe is in intimate contact with the primary pipe, the product can become trapped in the
secondary containment and build up pressure. Trapped product can indicate that there is a breach in the primary containment in
that section. This investigation technique may not be reliable if the secondary containment system is open to migration of releases
from sumps unless the product trapped in the secondary is under pressure. The user should assess the potential quantity of product
E2733 − 23
that could be trapped in the secondary containment and be prepared to capture the released product with absorbent pads and
containers such as those described in Guide F1127.
5.8.4 Soap Test—Soap tests can be conducted using the manufacturer’s recommended practice or standard industry methods such
as those described in PEI and API installation guides (PEI/RP 100).
5.8.5 Groundwater and soil testing can be used to confirm that a release has occurred and to determine what product was released
and when it occurred. There are a variety of field and laboratory techniques for assessing soil and groundwater constituent
concentrations. The user should consult with an contamination assessment professional a petroleum release remediation consultant
to determine which techniques to employ and the skills and equipment needed. Most authorities having jurisdiction require
assessment or testing requirements including specific analytical testing methods to investigate suspected releases and for proper
closure of tanks or piping of a UST system. See Fig. 1.
5.8.5.1 Source Area Identification—Concentrations from several sample locations can be plotted on a map to indicate the likely
area of highest concentration. The area of highest concentration is also often the area of the release. A three-dimensional plot
method such as a box diagram may be helpful, particularly for analyzing the tank excavation area.
5.8.5.2 Age of Fuel—Regulated Substance—In some cases the age of the petroleum regulated substance can be estimated. There
are a variety of techniques that can be used on free product, contaminated soil, and groundwater. Estimating the age of the
petroleum regulated substance may help determine if more than one release has occurred or if the release occurred prior to a repair
or replacement date. Various forensic analysis may be utilized for age dating. Some examples include gas chromatography and
mass spectrometry (GC/MS), high resolution gas chromatographic
...