EPA/530-SW-85-021
October 1985
Construction Quality Assurance
For Hazardous Waste Land Disposal Facilities
Public Comment Draft
68-02-3992
Task 032
Project Officer
Jonathan G. Herrmann
Land Pollution Control Division
Hazardous Waste Engineering Research Laboratory
Cincinnati, Ohio 45268
In cooperation with
Office of Solid Waste and Emergency Response
U.S. Environmental Protection Agency
Washington, DC 20460
Hazardous Waste Engineering Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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DISCLAIMER
This report was prepared by C. M. Northeim and R. S. Truesdale of the
Research Triangle Institute (RTI), Research Triangle Park, North Carolina,
under Contract Number 68-02-3992, Task 032. The U.S. Environmental Protec-
tion Agency (EPA) Project Officer was J. G. Herrmann of the Hazardous V/aste
Engineering Research Laboratory, Cincinnati, Ohio. Substantial input and
guidance were received from Les Otte of the Office of Solid Waste.
This is a draft guidance document that is being distributed by EPA for
comment on the accuracy and usefulness of the information it contains. The
report has received extensive technical review, but the Agency's peer and
administrative review process has not yet been completed. Therefore it
does not necessarily reflect the views or policies of the Agency. Mention
of trade names or commercial products does not constitute endorsement or
recommendation for use.
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FOREWORD
Today's rapidly developing and changing technologies and industrial
products and practices frequently carry with them the increased generation
of solid and hazardous wastes. These materials, if improperly dealt with,
can threaten both public health and the environment. Abandoned waste sites
and accidental releases of toxic and hazardous substances to the environment
also have important environmental and public health implications. The
Hazardous Waste Engineering Research Laboratory assists in providing an
authoritative and defensible engineering basis for assessing and solving
these problems. Its products support the policies, programs, and regulations
of the Environmental Protection Agency; the permitting and other responsi-
bilities of State and local governments; and the needs of both large and
small businesses in handling their wastes responsibly and economically.
This guidance document, prepared in cooperation with the Office of
Solid Waste, presents the elements of a construction quality assurance plan
that should be addressed during the permit application proce'dure for a
, specific site. These elements include: (1) areas of responsibility and
•\
lines of authority in executing the plan; (2) requisite qualifications of
the construction quality assurance personnel; (3) types of inspection
activities (observations and tests) to be performed as part of the construc-
tion quality assurance activity during construction; (4) sampling require-
ments (including sampling frequency, size, and location; acceptance and
rejection criteria; and corrective action procedures); and (5) documentation.
The document discusses management of construction quality for the construc-
tion or installation of several facility components. These are foundations,
dikes, low-permeability soil liners, flexible membrane liners, leachate
collection systems, and cover systems.
David G. Stephan, Director
Hazardous Waste Engineering Research Laboratory
11
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PREFACE
Subtitle C of the Resource Conservation and Recovery Act (RCRA) requires
the U.S. Environmental Protection Agency (EPA) to establish a Federal
hazardous waste management program. This program must ensure that hazardous
wastes are handled safely from generation until final disposition. EPA
issued a series of hazardous waste regulations under Subtitle C of RCRA
that are published in Title 40 Code of Federal Regulations (CFR) Parts 260
through 265 and Parts 122 through 124.
Parts 264 and 265 of 40 CFR contain standards applicable to owners and
operators of all facilities that treat, store, or dispose of hazardous
wastes. Wastes are identified or listed as hazardous under 40 CFR Part 261.
Part 264 standards are implemented through permits issued by authorized
States or EPA according to 40 CFR Part 122 and Part 124 regulations. Land
treatment, storage, and disposal (LTSD) regulations in 40 CFR Part 264
issued on July 26, 1982, and July 15, 1985, establish performance standards
for hazardous waste landfills, surface impoundments, land treatment units,
and waste piles. Part 265 standards impose minimum technology requirements
on the owners/operators of certain landfills and surface impoundments.
EPA is developing three types of documents for preparers and reviewers
of permit applications for hazardous waste LTSD facilities. These types
include RCRA Technical Guidance Documents, Permit Guidance Manuals, and
Technical Resource Documents (TRDs).
The RCRA Technical Guidance Documents present design and operating
specifications or design evaluation techniques that generally comply with
or demonstrate compliance with the Design and Operating Requirements and
the Closure and Post-Closure Requirements of Part 264.
The Permit Guidance Manuals are being developed to describe the permit
application information the Agency seeks and to provide guidance to appli-
cants and permit writers in addressing information requirements. These
manuals will include a discussion of each step in the permitting process
i v
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and a description of each set of specifications that must be considered for
inclusion in the permit.
The Technical Resource Documents present summaries of state-of-the-art
technologies and evaluation techniques determined by the Agency to constitute
good engineering designs, practices, and procedures. They support the RCRA
Technical Guidance Documents and Permit Guidance Manuals in certain areas
(i.e., liners, leachate management, closure covers, and water balance) by
describing current technologies and methods for designing hazardous waste
facilities or for evaluating the performance of a facility design. Although
emphasis is given to hazardous waste facilities, the information presented
in these TRDs may be used for designing and operating nonhazardous waste
LTSD facilities as well. Whereas the RCRA Technical Guidance Documents and
Permit Guidance Manuals are directly related to the regulations, the infor-
mation in these TRDs covers a broader perspective and should not be used to
interpret the requirements of the regulations.
This Technical Guidance Document is a first edition draft being made
available for public review and comment. It has undergone review by recog-
nized experts in the technical areas covered, but Agency peer review process-
ing has not yet been completed. Public comment is desired on the accuracy
and usefulness of the information presented in this document. Comments
received will be evaluated, and suggestions for improvement will be incor-
porated, wherever feasible, before publication of the second edition.
Communications should be addressed to: Project Officer—Construction
Quality Assurance, U.S. Environmental Protection Agency, Land Pollution
Control Division, Room 461, 26 W. St. Clair St., Cincinnati, OH 45268.
The document under discussion should be identified by title and number--
"Construction Quality Assurance for Hazardous Waste Land Disposal Facilities"
(EPA/530-SW-85-021).
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ABSTRACT
The U.S. Environmental Protection Agency's (EPA's) construction quality
assurance (CQA) program is a two-part program established to ensure, with a
reasonable degree of certainty, that a completed hazardous waste land
disposal facility meets or exceeds all design criteria, plans, and specifi-
cations. The first part of this program includes regulations and guidelines
that reguire the implementation of CQA during construction and outline
recommended elements of a CQA program. The second part, addressed by this
document, is guidance that addresses the site-specific components of a CQA
plan. This document covers CQA for hazardous waste landfills, surface
impoundments, and wastepiles. The major components of these facilities
that are addressed include foundations, dikes, low-permeability soil liners,
flexible membrane liners, leachate collection systems (primary and secondary),
and cover systems.
The CQA plan is a site-specific document that should be submitted
during the permitting process to satisfy EPA's CQA reguireme'nts. At a
minimum, the CQA plan should include five elements, which are briefly
summarized below.
Responsibility and Authority--The responsibility and author-
ity of all organizations and key personnel involved in
permitting, designing, and constructing the hazardous waste
land disposal facility should be described fully in the CQA
plan.
CQA Personnel Qualifications--The qualifications of the CQA
officer and supporting inspection personnel should be presented
in the CQA plan to demonstrate that they possess the training
and experience necessary to fulfill their identified responsi-
bilities.
Inspection Activities—The observations and tests that will
be used to monitor the installation of the hazardous waste
land disposal facility components should be summarized in
the CQA plan.
vi
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Sampling Requirements—The sampling activities, sample size,
sample locations, frequency of testing, acceptance and
rejection criteria, and plans for implementing corrective
measures as addressed in the project specifications should
be presented in the CQA plan.
Documentation--Reporting requirements for CQA activities
should be described in detail in the CQA plan. This should
include such items as daily summary reports, inspection data
sheets, problem identification and corrective measures
reports, block evaluation reports, design acceptance reports,
and final documentation. Provisions for the final storage
of all records also should be presented in the CQA plan.
This document describes these elements in detail and presents guidance on
those activities pertaining to each of the elements that are necessary to
ensure, with a reasonable degree of certainty, that a completed facility
meets or exceeds all design criteria, plans, and specifications. It is
intended for the use of organizations involved in permitting, designing,
and constructing hazardous waste land disposal facilities, including treat-
ment, storage, and disposal units.
This report was submitted in fulfillment of Contract No. 68-02-3992,
Task 032, by the Research Triangle Institute under the sponsorship of the
U.S. Environmental Protection Agency. This report covers the period October
1984 to October 1985. Work was completed as of October 24, .1985.
VI 1
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CONTENTS
Foreword -j-ji
Preface iv
Abstract vi
Figures xi
Tables xi
Acknowledgments xii
1.0 Introduction 1
1.1 Document Purpose 1
1.2 Applicability to Minimum Technology Guidance 2
1.3 Document Users 3
1.4 Key Concepts 3
1.4.1 Management of Construction Quality 3
1.4.2 Construction Quality Assurance Program 4
1.4.3 Construction Quality Assurance Plan 4
1.5 Document Scope and Limitations 4
2.0 Elements of a Construction Quality Assurance Plan 6
2.1 Responsibility and Authority 7
2.1.1 Organizations Involved in CQA 7
2.1.1.1 Permitting Agency 7
2.1.1.2 Facility Owner/Operator 8
2.1.1.3 Design Engineer 8
2.1.1.4 CQA Personnel 8
2.1.1.5 Construction Contractor 10
2.1.2 Project Meetings 10
2.1.2.1 Resolution Meeting 11
2.1.2.2 Preconstruction Meeting 11
2.1.2.3 Progress Meetings 12
2.1.2.4 Problem or Work Deficiency Meeting 12
2.2 Personnel Qualifications 13
2.2.1 CQA Officer 13
2.2.2 Inspection Staff 14
2.2.3 Consultants 14
2.3 Inspection Activities 14
2.3.1 General Preconstruction Activities 15
2.3.2 Foundation 16
VI 1 I
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CONTENTS (continued)
2.3.2.1 Reconstruction 17
2.3.2.2 Construction 17
2.3.2.3 Postconstruction 19
2.3.3 Dikes 19
2.3.3.1 Reconstruction 20
2.3.3.2 Construction 21
2.3.3.3 Postconstruction 22
2.3.4 Low-Permeability Soil Liners 23
2.3.4.1 Reconstruction 23
2.3.4.2 Construction 30
2.3.4.3 Postconstruction 33
2.3.5 Flexible Membrane Liners 34
2.3.5.1 Reconstruction 34
2.3.5.2 Construction 40
2.3.5.3 Postconstruction 46
2.3.6 Leachate Collection Systems 46
2.3.6.1 Reconstruction 47
2 3.6.2 Construction 48
2.3.6.3 Postconstruction • 56
2.3.7 Final Cover Systems 56
2.3.7.1 Reconstruction 57
2.3.7.2 Construction 58
2.3.7.3 Postconstruction 64
2.4 Sampling Requirements 65
2.4.1 Definitions of Sampling Terms 66
2.4.2 Sampling Strategies 67
2.4.2.1 100-Porcent Sampling 67
2.4.2.2 Judgment Sampling 68
2.4.2.3 Statistical Sampling 68
2.4.3 Selection of Sample Size 71
2.4.3.1 Judgment Method 71
2.4.3.2 Statistical Methods 72
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CONTENTS (continued)
Page
2.4.4 Treatment of Outliers 76
2.4.5 Corrective Measures Implementation 77
2.4.6 Control Charts 78
2.5 Documentation 84
2.5.1 Daily Recordkeeping 84
2.5.1.1 Daily Summary Report 84
2.5.1.2 Inspection Data Sheets 85
2.5.1.3 Problem Identification and Corrective
Measures Reports 86
2.5.2 Photographic Reporting Data Sheets 87
2.5.3 Block Evaluation Reports 88
2.5.4 Design Engineer's Acceptance of Completed
Components 89
2.5.5 Final Documentation 89
2.5.5.1 Responsibility and Authority 90
2.5.5.2 Relationship to Permitting Agencies .... 90
2.5.6 Storage of Records 90
References 91
Appendix A. Inspection Methods Used During the Construction
of Hazardous Waste Land Disposal Facilities 95
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FIGURES
Number Page
2-1 Schematic of a test fill 28
2-2 Schematic of a test fill equipped to allow quanti-
fication of underdrainage 29
2-3 Control charts, individual and moving average 81
2-4 Rejection chart for dam core compaction control 82
2-5 Frequency diagrams: density measurements for dam core
compaction control 83
TABLE
Number Page
2-1 Moisture/Density Test Frequency Recommendations for
Earthwork Quality Control 73
XI
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ACKNOWLEDGMENTS
This report was prepared for the U.S. Environmental Protection Agency
under Contract No. 68-02-3992, Task 032, to the Research Triangle Institute.
The authors are grateful to Jonathan G. Herrmann, the EPA Technical Project
Monitor, and to Robert P. Hartley, Robert E. Landreth, Dr. Walter E. Grube,
Daniel Greathouse, Kent Anderson, and Alessi D. Otte, also of the U.S.
Environmental Protection Agency, for their advice and technical guidance.
The authors also would like to acknowledge the following individuals
who have contributed information to sections of this document and earlier
drafts:
Doug Allen of E. C. Jordan Company
David Anderson of K. W. Brown & Associates, Inc.
Salvatore Arlotta of Wehran Engineering
Jeffrey Bass of Arthur D. Little, Inc.
Dirk Brunner of E. C. Jordan Company
Peter Fleming of Atec Associates, Inc.
Jack Fowler of USAE Waterways Experiment Station
J. P. Giroud of Geo Services, Inc.
James Harmston of American Foundations
Louis R. Hovater of Hovater-MYK Engineers
Walter Ligget of National Bureau of Standards
R. J. Lutton of USAE Waterways Experiment Station
John G. Pacey of Emcon Associates
S. Joseph Spigolon, Engineering Consultant
James Withiam of D'Appolonia Consulting Engineers, Inc.
Leonard 0. Yamamoto of Hovater-MYK Engineers
XII
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1.0 INTRODUCTION
1.1 DOCUMENT PURPOSE
This document presents guidance for preparing a site-specific con-
struction quality assurance (CQA) plan for a hazardous waste land disposal
facility (i.e., landfill, surface impoundment, or waste pile). The guidance
describes the elements of a CQA program that the U.S. Environmental Pro-
tection Agency (EPA) believes are necessary to ensure, with a reasonable
degree of certainty, that a completed facility meets or exceeds all design
criteria, plans, and specifications.
EPA believes that a site-specific CQA plan is needed to address each
of the components of a hazardous waste land disposal facility. The hazard-
ous waste land disposal facility components discussed in this document
include:
Foundations
Dikes
Low-permeability soil liners
Flexible membrane liners (FMLs)
Leachate collection systems (LCSs)
Final cover systems.
Development of comprehensive guidance for these components is being
prepared by the Hazardous Waste Engineering Research Laboratory (HWERL) in
close cooperation with the Office of Solid Waste (OSW). HWERL is using a
two-phased program to meet the goals of the CQA guidance. This document is
the result of Phase 1 of this program and provides currently available
information on CQA for each element of a site-specific CQA plan. Phase 2
will develop comprehensive construction quality assurance guidance through
a research program that will gather information on areas not addressed in
detail in Phase 1.
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1.2 APPLICABILITY TO MINIMUM TECHNOLOGY GUIDANCE
The Hazardous and Solid Waste Amendments of 1984 (HWSA) require that
the owner/operator of an interim status hazardous waste land disposal
facility who constructs a new unit, laterally expands an existing unit, or
replaces an existing unit must comply with the minimum technological require-
ments of §3004(o) with respect to waste received after May 8, 1985. Before
a permit is issued, the facility owner/operator is required to show that
the liner and leachate collection systems installed during interim status
were installed in good faith compliance with EPA's regulations and guidance
documents.
One part of the facility owner/operator's burden of demonstrating good
faith compliance is presenting evidence that the liner and leachate collec-
tion systems were designed and installed in accordance with EPA's regula-
tions and guidance on double liner systems. The records required for
making a good faith demonstration must show that the design and construc-
tion of the unit conform to the applicable regulations and guidance. As
part of this demonstration, a site-specific CQA plan should be prepared and
implemented, and its implementation must be adequately documented. The
specific elements that should be included in the CQA plan are identified
and addressed in EPA's technical guidance on double liner systems (EPA/530-
SW-85-014) and are discussed in greater detail in Section 2.0 of this
document.
The site-specific CQA plan and the required CQA documentation should
be retained at the facility. They may be reviewed during a site inspection
and will be the chief means for the facility owner/operator to demonstrate
to the permit writer that EPA's technical guidance for installing a double
liner system has been followed. The permit writer should expect the facility
owner/operator to make this demonstration at the time of permit review,
which may be some time after the units have been lined and are in use.
Therefore, it is important that the owner/operator prepare a CQA plan that
clearly demonstrates that he followed the EPA technical guidance on double
liner systems when installing the liners and leachate collection systems.
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1.3 DOCUMENT USERS
This document is intended for use by organizations involved in per-
mitting, designing, and constructing hazardous waste land disposal facil-
ities.
Permitting agencies (i.e., State agencies and the U.S. Environmental
Protection Agency) may use this document when reviewing site-specific CQA
plans to help establish the completeness of a submitted CQA plan and to
ensure its implementation. This document also may be used by facility
owner/operators to make certain that all aspects of CQA are covered in
their permit applications by helping them critically review a site-specific
CQA plan prepared by their supporting organizations (i.e., design engineer,
CQA personnel, construction contractor).
Design engineers hired by the facility owner/operator may use this
document as a guide in preparing a site-specific CQA plan. It also may
enable design engineers to identify weaknesses and confirm strengths in
their own standard CQA programs for hazardous waste land disposal facilities.
CQA personnel may use this document as a convenient reference and aid in
administering site-specific CQA plans. Construction contractors also may
use this document as a reference that outlines the inspection activities to
which their work may be subjected or as guidance for implementing their own
construction quality control programs.
1.4 KEY CONCEPTS
1.4.1 Management of Construction Quality
The management of construction quality is the responsibility of the
facility owner/operator and involves using scientific and engineering
principles and practices to ensure, with a reasonable degree of certainty,
that a constructed hazardous waste land disposal facility meets or exceeds
all design criteria, plans, and specifications. This management activity
begins during the design of the facility, continues throughout construction,
and ends when the completed facility is accepted by the owner/operator.
Construction quality management comprises both a planned system of
inspection activities that are necessary to monitor and control the quality
of a construction project and a planned system of overview activities that
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provide assurance that these inspection activities are being properly
performed and documented and that the resulting data are properly inter-
preted. For hazardous waste land disposal facilities, CQA may involve
verifications, audits, and evaluations of the factors that affect the
installation, inspection, and performance of the facility to ensure, with a
reasonable degree of certainty, that the facility meets or exceeds the
specified design.
1.4.2 Construction Quality Assurance Program
The CQA program discussed in this document is EPA's approach to CQA
for hazardous waste land disposal facilities. This program is divided into
two parts: (1) regulations/guidelines that specify the use of CQA during
construction and outline the elements of the CQA program, and (2) guidance
that addresses the elements of a site-specific CQA plan. This document is
the result of one phase of the second part of EPA's CQA program.
1.4.3 Construction Quality Assurance Plan
This document provides guidance for preparing a CQA plan—the facility
owner/operator's site-specific written response to EPA's CQA program. The
purpose of this plan is to ensure, with a reasonable degree of certainty,
that a completed facility meets or exceeds all design criteria, plans, and
specifications. Although CQA is, by definition, a system of overview
activities, the CQA plan also must include a detailed description of the
inspection activities that will be used to monitor and control construction
qua!ity.
The CQA plan documents the owner/operator's commitment to CQA and
should be tailored to the specific facility to be constructed. The facility
owner/operator's CQA plan should be included in the permit application.
The permitting agency should review the plan for completeness and confirm
that it is implemented.
1.5 DOCUMENT SCOPE AND LIMITATIONS
This document is a compilation of information on construction quality
assurance and is limited in its scope and function in the following ways.
Kirst, although the document provides information on state-of-the-art CQA
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for hazardous waste land disposal facilities, it is not necessarily compre-
hensive. Researching and evaluating all possible sources of effective CQA
guidance and procedures were beyond the scope of, and outside the time
frame available for, this effort. Second, this document should not be
construed to present design procedures for hazardous waste land disposal
facilities. That remains the responsibility of the design engineer and
should be based on site-specific conditions.
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2.0 ELEMENTS OF A CONSTRUCTION QUALITY ASSURANCE PLAN
The facility owner/operator should prepare a written CQA plan as part
of the permit application. Although the overall content of the CQA plan
will depend on the site-specific nature of the proposed hazardous waste
land disposal facility, at a minimum several specific elements should be
included in the plan. These elements are summarized briefly below.
Responsibility and Authority--The responsibility and author-
ity of all organizations and key personnel involved in
permitting, designing, and constructing the hazardous waste
land disposal facility should be described fully in the CQA
plan.
CQA Personnel Qualifications--The qualifications of the CQA
officer and supporting inspection personnel should be presented
in the CQA plan to demonstrate that they possess the training
and experience necessary to fulfill their identified responsi-
bi1ities.
Inspection Activities—The observations and tests that will
be used to monitor the installation of the hazardous waste
land disposal facility components should be summarized in
the CQA plan.
Sampling Requirements—The sampling activities, sample size,
sample locations, frequency of testing, acceptance and
rejection criteria, and plans for implementing corrective
measures as addressed in the project specifications should
be presented in the CQA plan.
Documentation--Reporting requirements for CQA activities
should be described in detail in the CQA plan. This should
include such items as daily summary reports, inspection data
sheets, problem identification and corrective measures
reports, block evaluation reports, design acceptance reports,
and final documentation. Provisions for the final storage
of all records also should be presented in the CQA plan.
Each of these elements is described in greater detail in the following
subsections.
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2.1 RESPONSIBILITY AND AUTHORITY
2.1.1 Organizations Involved in CQA
The principal organizations involved in permitting, designing, and
constructing a hazardous waste land disposal facility include the permitting
agency, facility owner/operator, design engineer(s), CQA personnel, and
construction contractor(s). Except for the permitting agency, the principal
parties will not necessarily be independent of each other: the facility
owner/operator also may be the construction contractor; the design engineer
also may be the construction contractor; the CQA personnel may be employees
of the facility owner/operator, of the design engineer, or of an independent
firm. Regardless of the relationships among the parties, it is essential
that the areas of responsibility and lines of authority for each party be
clearly established as the first element of the CQA plan. For example, it
is very important that the CQA officer be at the same authority level as
the construction superintendent and not be responsible to him or her. This
will help establish the necessary lines of communication that will facilitate
an effective decisionmaking process during implementation of the site-
specific CQA plan.
2.1.1.1 Permitting Agency--
The permitting agency (i.e., State agencies and U.S. Environmental
Protection Agency) is authorized by law and regulation to issue a permit
for the construction and operation of a hazardous waste land disposal
facility. It is the responsibility of the permitting agency to review the
facility owner/operator's permit application, including the site-specific
CQA plan, for compliance with the agency's requirements (i.e., regulations)
and to write a permit or deny the application based on this review. The
agency will have the responsibility and authority to review and accept or
reject any design revisions or requests for variance that are submitted by
the facility owner/operator after the permit is written. The agency also
may review CQA records during or after facility construction to confirm,
with a reasonable degree of certainty, that the facility was constructed so
that it meets or exceeds all design criteria, plans, and specifications.
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2.1.1.2 Facility Owner/Operatoi—
The facility owner/operator is responsible for the design, construction,
and operation of the hazardous waste land disposal facility. This responsi-
bility includes complying with the requirements of the permitting agency in
order to obtain a permit and assuring the agency, by the submission of CQA
documentation, that the facility was constructed, with a reasonable degree
of certainty, to meet or exceed all design plans, criteria, and specifica-
tions. The owner/operator has the authority to select and dismiss parties
charged with design, CQA, and construction activities. The owner/operator
also has the authority to accept or reject design plans and specifications,
CQA plans, progress reviews and recommendations of the CQA officer, and the
materials and workmanship of the contractor.
2.1.1.3 Design Engineer--
The design engineer's primary responsibility is to design a hazardous
waste land disposal facility that fulfills the needs of the facility owner/
operator in terms of facility function and that meets the requirements of
the facility owner/operator's submittal to the permitting agency. Design
activities do not end until the facility is completed; the design engineer
may have to change some design elements if unexpected site conditions are
encountered or changes in construction methodology occur that, could adversely
affect facility performance. CQA provides assurance that these unexpected
changes or conditions will be detected, documented, and corrected during
construction.
Additional responsibility and authority may be delegated to the design
engineer by the expressed consent (i.e., a contractual agreement) of the
facility owner/operator. Additional responsibility and authority may
include formulating and implementing a site-specific CQA plan, periodic
review of CQA documentation data sheets and reports, modifying construction
site activity, and specifying corrective measures in cases where deviation
from the specified design or failure to meet design criteria, plans, and
specifications is detected by the CQA personnel.
2.1.1.4 CQA Personnel--
The overall responsibility of the CQA personnel is to perform those
activities specified in the CQA plan. At a minimum, CQA personnel should
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include a CQA officer and the necessary supporting inspection staff. The
specific responsibilities and authority of each of these individuals should
be defined clearly in the CQA plan and associated contractual agreements
with the facility owner/operator. For the CQA officer, specific responsibil-
ities may include:
Reviewing design drawings and specifications for clarity and
completeness
Serving as the owner/operator's or design engineer's liaison
with the construction contractor in interpreting and clarify-
ing project drawings and specifications
Educating construction and inspection personnel on job
requirements
Scheduling site inspections
Directing and supporting the inspection staff in performing
observations and tests by:
submitting blind samples (knowns and blanks) for analysis
by the inspection staff and one or more independent
laboratories
confirming that the testing equipment, personnel, and
procedures do not change over time or making sure that
any changes do not result in a deterioration of the
inspection process
confirming that the test data are accurately recorded
and maintained (this may involve selecting reported
results and backtracking them to the original hand-
written log and laboratory data sheets)
verifying that the raw data are properly summarized and
interpreted
Providing to the facility owner/operator reports on the
inspection results including:
reviews and interpretations of observation records and
test results
identification of work that the CQA officer believes
should be accepted, rejected, or uncovered for observa-
tion, or that may require special testing, inspection,
or approval
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reports that reject defective work and specify corrective
measures
Verifying that the contractor's construction quality control
plan is being followed.
For the supporting inspection staff, specific responsibilities may
include:
Verifying that the equipment used in testing meets the test
requirements and that the tests are conducted by qualified
personnel according to the standardized procedures defined
by the CQA plan
Monitoring all tests conducted by the contractor's personnel
as may be required by the contract and/or the design specifi-
cations
Performing independent onsite inspection of the work in
progress to assess compliance by the contractor with the
facility design criteria, plans, and specifications
Reporting to the contractor results of all observations and
tests as the work progresses and interacting with the contrac-
tor to provide assistance in modifying the materials and
work to comply with the specified design
Reporting to the CQA officer results of all inspections
including work that is not of acceptable quality or fails to
meet the specified design.
2.1.1.5 Construction Contractor--
It is the responsibility of the construction contractor to construct
the hazardous waste land disposal facility in strict accordance with design
criteria, plans, and specifications, using the necessary construction
procedures and techniques. This responsibility may be expanded, as part of
the contractual agreement with the facility owner/operator, to include
formulating and implementing a plan for construction quality control as an
adjunct to the CQA plan. The construction contractor has the authority to
direct and manage his employees and the equipment they use to accomplish
the construction.
2.1.2 Project Meetings
Periodic meetings held during the life of the project will enhance the
responsibility and authority associated with permitting, designing, and
10
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constructing a hazardous waste land disposal facility. Conducting periodic
project meetings is the responsibility of the facility owner/operator; he
may delegate that responsibility to one of his supporting organizations
(e.g., design engineer). Regardless of who conducts them, periodic project
meetings benefit all those involved with the facility by ensuring familiarity
with facility design, construction procedures, and any design changes. The
types of meetings that may be held are discussed in the following subsections.
2.1.2.1 Resolution Meeting--
A meeting should be held to resolve any uncertainties following the
completion of the design criteria, plans, and specifications and the site-
specific CQA plan for the facility. The facility owner/operator, design
engineer, and CQA officer should all be present. The purpose of this
meeting is to:
Provide each organization with all relevant documents and
supporting information
Review the design criteria, plans, and specifications
Review the CQA plan
Make any appropriate modifications to the design criteria,
plans, and specifications so that the fulfillment of all
design specifications or performance standards can be deter-
mined through the implementation of the site-specific CQA
plan
Make any appropriate modifications to the CQA plan to ensure
that it specifies all CQA activities that are necessary to
determine if design criteria, plans, and specifications can
be measured.
The meeting should be documented by a designated person, and minutes should
be transmitted to all parties.
2.1.2.2 Reconstruction Meeting--
A preconstruction meeting should be held at the site. At a minimum,
the meeting should be attended by the design engineer, the CQA personnel,
and the construction contractor(s). The purpose of the preconstruction
meeting is to:
Review the responsibilities of each organization
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Review lines of authority and communication for each organi-
zation
Discuss the established protocol for observations and tests
Discuss the established protocol for handling construction
deficiencies, repairs, and retesting
Review methods for documenting and reporting inspection data
Review methods for distributing and storing documents and
reports
Review work area security and safety protocol
Discuss any appropriate modifications of the construction
quality assurance plan to ensure that site-specific consider-
ations are addressed
Discuss procedures for the protection of materials and for
the prevention of damage from inclement weather or other
adverse events
Conduct a site walk-around to verify that the design criteria,
plans, and specifications are understood and to review
material and equipment storage locations.
The meeting should be documented by a designated person and minutes should
be transmitted to all parties.
2.1.2.3 Progress Meetings--
A progress meeting should be held daily at the work area just prior to
commencement of work. At a minimum, the meeting should be attended by the
construction contractor(s) and the CQA personnel. The purpose of the
meeting is to:
Review the previous day's activities and accomplishments
Review the work location and activities for the day
Identify the contractor's personnel and equipment assignments
for the day
Discuss any potential construction problems.
This meeting should be documented by a member of the inspection staff.
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2.1.2.4 Problem or Work Deficiency Meetings--
A special meeting may be held when and if a problem or deficiency is
present or likely to occur. At a minimum, the meeting should be attended
by the construction contractor(s) and the inspection staff. The CQA officer
should attend those meetings that include discussions of severe or recurring
problems. The purpose of the meeting is to define and resolve the problem
or recurring work deficiency in the following manner:
Define and discuss the problem or deficiency
Review alternative solutions
Implement a plan to resolve the problem or deficiency.
The meeting should be documented by a member of the inspection staff.
2.2 PERSONNEL QUALIFICATIONS
The construction quality assurance plan should include a specific
section that presents the CQA officer and the inspection staff assigned to
the project (identifying them by name if possible), documenting their
education and experience and describing their expected duties.
Hazardous waste land disposal facilities are uniquely engineered
structures designed primarily to contain toxic or noxious ch,emical compounds.
Therefore, it is critical that day-to-day CQA activities are oriented to
ensure, with a reasonable degree of certainty, that the completed facility
meets or exceeds the design criteria, plans, and specifications. This
requirement may demand that the CQA officer, inspection staff, and any
consultants use techniques or ensure that techniques are used that are
different both in concept and performance from inspection activities rou-
tinely accepted in civil or military construction.
2.2.1 CQA Officer
The CQA officer is that individual assigned singular responsibility
for all aspects of the construction quality assurance plan. The CQA officer
is responsible to the facility owner/operator and should be independent of
jurisdiction from the construction contractor(s). The location of the CQA
officer within the overall organizational structure of the project, including
the facility owner/operator, design engineer, construction contractor, and
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permitting agencies, should be clearly described within the CQA plan as
noted in the previous discussion on responsibility and authority.
The CQA officer should possess adequate formal academic training in
engineering, engineering geology, or closely associated disciplines and
sufficient practical, technical, and managerial experience to successfully
oversee and implement construction quality assurance activities for hazard-
ous waste facilities. Since the CQA officer will be expected to interrelate
with all levels of personnel involved in the project, good communication
skills are essential. The CQA officer should be expected to ensure that
communication of all CQA-related matters is conveyed to and acted upon by
the affected organizations.
2.2.2 Inspection Staff
The inspection staff should possess adequate formal training and
sufficient practical technical and administrative experience to execute and
record inspection activities successfully. This should include demonstrated
knowledge of specific field practices relating to construction techniques
used for hazardous waste land disposal facilities, all codes and regulations
concerning material and equipment installation, observation and testing
procedures, equipment, documentation procedures, and site safety.
2.2.3 Consultants
Authorities in engineering geology, geotechnical engineering, geology,
soil science, chemistry, and other technical disciplines may be called in
from external organizations in the event of unusual site conditions or test
results. The CQA plan should prescribe detailed documentation when expert
technical judgments are obtained and used as a basis for decision in some
aspect of construction or design compromise. Consultants should not be
employed as a substitute for objective data collection and interpretation
when suitable tests are available.
2.3 INSPECTION ACTIVITIES
The third element of the CQA plan should describe the inspection
activities (observations and tests) that will be performed during hazardous
waste land disposal facility construction. The scope of this discussion
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should cover only the construction of the facility. It is assumed that the
site has been characterized adequately, including evaluation of the hydro-
geologic environment. It is also assumed that a site-specific facility
design has been prepared that is acceptable to the facility owner/operator
and that it has been evaluated to ensure its technical correctness and
feasibility.
The objective of inspection by the CQA personnel during construction
is to determine whether the properties, composition, and performance of
materials or installed components are within the limits established by the
design specifications. Inspection may include evaluating the quality and
assembly of materials and evaluating performance under specified test
conditions.
This section addresses the inspection activities that are necessary to
ensure, with a reasonable degree of certainty, that the completed facility
meets the design criteria, plans, and specifications. The first subsection
addresses general preconstruction activities applicable to all facility
components. The subsequent subsections address each facility component
separately and are further subdivided into sections on preconstruction,
construction, and postconstruction inspection activities unique to each
component. Specific test methods that may be used to inspect the components
of a hazardous waste land disposal facility are listed and referenced in
Appendix A.
2.3.1 General Preconstruction Activities
The CQA officer should review the design drawings and specifications
for the hazardous waste land disposal facility to be constructed. The
design criteria, plans, and specifications need to be understandable to
both the CQA personnel and the construction contractor. If the design is
deemed unclear by the CQA officer, it should be returned to the design
engineer for clarification or modification.
Before construction, the CQA officer, with the assistance of the
inspection staff, should assess the capabilities of the construction contrac-
tor's personnel to determine the type and amount of instruction, training,
and supervision needed during all phases of construction. The contractor's
prior- performance in general construction activities, experience in con-
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strutting hazardous waste land disposal facilities, and experience in
working with the specific materials and equipment to be used in constructing
the facility should be addressed in this assessment. The CQA officer also
may want to evaluate the contractor's ability to perform a specific task
before task performance during facility construction. The evaluation
should include the performing of specific tasks under the same environ-
mental conditions and using the same equipment and procedures specified in
the design.
It may be necessary to include a preconstruction training program in
the site-specific CQA plan. As stated by the U.S. Department of the Army's
Construction Control for Earth and Rock-Fill Dams (1977):
Preconstruction instructions and training should be given to field
inspection personnel to acquaint them with design concepts and to
provide them with a clear understanding of expected conditions,
methods of construction, and the scope of plans and specifications.
This may be done by training sessions, preferably with design
personnel present, using a manual of written instructions prepared
especially for field personnel, to discuss engineering considera-
tions involved and to explain control procedures and required
results.
The ultimate decision on whether to implement a preconstruction training
program rests with the facility owner/operator but may be influenced by
recommendations of the supporting organizations.
2.3.2 Foundation
Foundations of hazardous waste land disposal facilities should provide
structurally stable subgrades for the overlying facility components. The
foundation also should provide satisfactory contact with the overlying
liner or other system component. In addition, the foundation should resist
settlement, compression, and uplift resulting from internal or external
pressure gradients, thereby preventing distortion or rupture of overlying
facility components.
It is assumed that, before construction, adequate site investigations
have been conducted and the foundation design has been developed to accommo-
date the expected site conditions. The following subsections describe the
quality assurance activities necessary to ensure, with a reasonable degree
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of certainty, that a foundation meets or exceeds the specified design.
Specific tests mentioned in this section are listed and referenced in
Appendix A.
2.3.2.1 Preconstruction--
It is especially important for all CQA personnel and the construction
contractor(s) to review site investigation information to familiarize
themselves with the expected site conditions upon which the facility designs
were based. This will help ensure that the CQA personnel will be able to
identify any unexpected site conditions that may be encountered during
foundation construction. Unexpected site conditions may necessitate modifi-
cations of the facility design and construction procedures by the design
engineer and the construction contractor to ensure component performance.
2.3.2.2 Construction--
To ensure that the design objectives for the foundation are met,
inspection activities during construction of the foundation should include
the following (U.S. Army, 1977):
Observations of soil and rock surfaces for adequate filling
of rock joints, clay fractures, or depressions, and removal
and filling of sand seams
Measurements of the depth and slope of the excavation to
ensure that it meets design requirements
Observations to ensure proper placement of any recessed
areas for collection or detection pipes and sumps
Tests and observations to ensure the quality of compacted
fill
Observations of stripping and excavation to ensure that
there are no moisture seeps and that all soft, organic, and
otherwise undesirable materials are removed. Proof-rolling
with heavy equipment can be used to detect soft areas likely
to cause settlement. Consistency of the foundation soil may
be checked with a hand penetrometer, field vane shear test,
or similar device.
In addition, when the foundation is to serve as the lower bedding layer for
an FML, inspection activities should include the following:
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Observations to ensure the removal of objects (e.g., roots
and rocks) that could penetrate the FML
Observations to ensure uniform application of herbicide,
when specified, to the foundation soil to prevent vegetation
from damaging the liner
Observations and tests to ensure that the surface is properly
compacted, smooth, uniform, and free from sudden changes in
grade.
Inspection activities during foundation construction will help ensure,
with a reasonable degree of certainty, that the facility meets or exceeds
all design criteria, plans, and specifications by preventing, detecting,
and correcting the following:
Sidewall slope failure from moisture seeps, weak foundation
soil, or sidewall slopes that are steeper than specified
Puddling or ponding on the foundation base, improper function-
ing of the leachate collection systems (LCS) resulting from
less than specified bottom slopes, and the unspecified
placement of recesses for LCS pipes and sumps
Flexible membrane liner damage from an improperly prepared
foundation (e.g., removing penetrating objects and sterilizing
the soil)
Foundation settlement due to soft areas in the foundation
base. Excessive differential settlement can result in
distortion or rupture of overlying facility components
Regions of high permeability in the foundation base, from
ungrouted joints or from the presence of high-permeability
foundation materials. Permeable zones can compromise the
ability of the foundation to serve as an additional barrier
to leachate migration and can present pathways for seepage
into the facility, causing blowout of the liner during
subsequent facility construction.
Continuous visual observation of the construction process is a major
means of ensuring that the foundation is constructed to meet or exceed the
specified design. Surveying will be necessary to ensure that facility
dimensions, side slopes, and bottom slopes are as specified in the design.
Visual-manual soil identification techniques and index property tests may
be used to monitor foundation soil composition. Cohesive soil consistency
may be checked in the field with a penetrometer, a hand-held vane shear
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device, or other suitable field-expedient measurement device (see Appendix).
These field-expedient methods give only approximate values. They are
usually sufficient for construction control or site material verification,
but they are not accurate or precise enough to be used for acceptance
testing; standard laboratory unconfined compression tests are adequate for
acceptance testing (Spigolon and Kelley, 1984). Compaction of soil backfill
is controlled as described in Section 2.3.3.2.1. Further information on
quality control of foundations may be found in Spigolon and Kelley (1984),
USSR (1974), and U.S. Army (1977).
2.3.2.3 Postconstruction--
Foundation completion tests include testing and proof-rolling to
ensure uniform foundation soil consistency, visually inspecting foundation
surfaces, and surveying to check elevations, slopes, and foundation bound-
aries.
2.3.3 Dikes
The purpose of a dike in a hazardous waste landfill, waste pile, or
surface impoundment is to function as a retaining wall, resisting the
lateral forces of the stored wastes. It is the aboveground extension of
the foundation, providing support to the overlying facility components.
Dikes therefore must be designed, constructed, and maintained with sufficient
structural stability to prevent massive failure. Dikes also can be used to
separate cells for different wastes within a large landfill or surface
impoundment.
Dikes may be constructed of pervious or impervious soil material.
This material is compacted as necessary to a specified strength, unlike
soil liner material, which is compacted for low permeability. Materials
other than soil, such as ash, slag, or building rubble, may be used to
construct dikes, as long as the design of the dike accommodates the partic-
ular material properties and proper installation procedures are followed.
Drainage layers and structures may be included in the dike design if condi-
tions warrant control of seepage. (Although seepage through the dike will
probably be prevented by the liner system, a dike should be designed to
maintain its integrity if the liner fails.)
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The following subsections describe the quality assurance activities
necessary to ensure, with a reasonable degree of certainty that a dike is
constructed to meet or exceed the specified design. Specific tests mentioned
in the following subsections are listed and referenced in Appendix A.
2.3.3.1 Reconstruction—
Reconstruction inspection activities for dikes include inspection of
the prepared foundation, inspection of incoming materials, and construction
of a test fill.
2.3.3.1.1 Materials inspection—Materials to be used for the dike
should be inspected. It is especially important that all dike materials
are uniform and as specified to ensure that no soft or structurally weak
materials are included in the dike. Procedures for inspecting soil materi-
als are discussed in Section 2.3.4.1.1.
2.3.3.1.2 Test fill construction—A test fill may be constructed to
verify that the specified soil density/moisture content/compactive effort/
strength relationships hold for field conditions and to determine construc-
tion equipment suitability. Test fill compaction is described in Section
2.3.4.1.2; unlike soil liner test fills, permeability tests are not necessary
on dike test fills; strength tests are necessary. Tests for shear strength
(e.g., undrained triaxial tests or unconfined compressive strength) are
appropriate for cohesive soils. Field-expedient methods of measuring
cohesive soil consistency (e.g., penetrometers or vane shear devices) may
be used to estimate unconfined compressive strength for construction control
purposes but are not sufficiently accurate for acceptance testing (Spigolon
and Kelley, 1984).
2.3.3.1.3 Foundation preparation--Foundation soil analyses should
include strength tests (e.g., unconfined compression or undrained triaxial
tests); compressive strength correlations with standard penetration tests
or vane shear tests may be used for construction control. If soft founda-
tion conditions necessitate excavation and replacement of foundation soils,
the excavation of the undesirable material and the placement and compaction
of soil in the excavation should be closely and continuously monitored by
inspection personnel. The fill material should be inspected to ensure that
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it is uniform and as specified. Section 2.3.3.2.1 describes inspection
procedures for compacted fill. Foundation quality control is described in
Section 2.3.2.
2.3.3.2 Construction--
Dike construction involves standard earthwork construction practices.
Dike construction activities may include fill placement and compaction,
drainage system construction, and implementation of erosion control measures.
Adequate CQA during dike construction will identify and correct problems
resulting from inadequate construction methodologies or materials that
could result in dike failure from slope instability, settlement, seepage
problems (e.g., piping, pore pressure changes), or erosion.
2.3.3.2.1 Compacted fill construction—Compacted fill may be present
in the dike core or may constitute the entire dike. Inspection activities
that should be conducted during fill emplacement, conditioning, and compac-
tion include:
Testing of fill material characteristics (see Section
2.3.4.1.1)
Measurement of loose lift thickness
Observation of clod size reduction and material homogeniza-
tion operations
Testing of water content
Observation of type of compaction equipment, number of
passes, and uniformity of compaction coverage
Testing of the density of the compacted fill
Observation of scarification and connection between compacted
fill lifts.
Inspection activities for compacted fill, including observations and specific
tests, are discussed in more detail in Section 2.3.4.2.
Specifications for compaction of dikes may differ from those for
low-permeability soil liners because the former are compacted for strength
and the latter are compacted to achieve low permeability. CQA inspection
activities are similar, however, except that permeability tests on undis-
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turbed samples are not required for dikes. In addition, strength tests are
more important for dikes than they are for soil liners. As with soil
liners, close visual observation during all phases of construction is a
critical aspect of CQA.
2.3.3.2.2 Dike shell construction--Semicompacted fill may be used to
form the dike shells surrounding a compacted core. This fill is generally
installed in a manner similar to that for compacted fill except that the
lighter equipment used for hauling and spreading the dike material may be
used to compact the shell material. As with compacted fill, uniformity of
the material is very important. CQA inspection activities that should be
conducted during dike shell installation include:
Testing of fill material characteristics
Measurement of loose lift thickness
Testing fill water content and compacted fill density
Observation of equipment type, number of passes, and routing
Measurement of dike slopes.
CQA activities for dike shells should be directed toward ensuring that
the shear strength and compressibility required by the design specifi-
cations are achieved.
2.3.3.2.3 Drainage systems installation—Installation procedures and
equipment for dike drainage systems are similar to those for leachate
collection systems. The observations and tests that are necessary to
monitor the installation of drainage system components are discussed in
Section 2.3.6.
2.3.3.2.4 Erosion control measures — Erosion control measures are
applied to the outer slopes of dikes and may include berms and vegetative
covers. Inspection activities necessary for ensuring the quality of erosion
control measures are the same ac, those for topsoil and vegetation subcompo-
nents of cover systems (see Sections 2.3.7.2.7 and 2.3.7.2.8).
2.3.3.3 Postconstruction—
Surveys and visual observations should be conducted to ensure that the
dimensions of the completed dike are as specified. Dike slopes are the
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most important items to check; if slopes are too steep they may be unstable
and eventually could fail. Other items to be checked include berm width,
crest width, overall height, thickness, and area! dimensions. Finally,
vegetative cover, when specified, should be inspected at regular intervals
after facility completion to ensure that vegetation is properly established.
2.3.4 Low-Permeabi1ity Soil Liners
The purpose of a low-permeability soil liner depends on the overall
liner system design. In the cases of single liners constructed of soil or
double liner systems with soil secondary liners, the soil liner's purpose
is to prevent constituent migration through the soil liner. In the case of
soil liners used as the lower component of a secondary composite liner, the
soil component serves as a protective bedding material for the FML upper
component and minimizes the rate of leakage through any breaches in the FML
upper component. An objective shared by all low-permeability soil liners
is to serve as long-term, structurally stable bases for all overlying
materials.
It is assumed that, before construction, adequate studies have been
conducted to ensure that the low-permeability soil liner can meet or exceed
the specified design. These studies should include soil 1iner-leachate
compatibility testing, laboratory soil density/moisture content/compactive
effort/ permeability relationships, grain size distribution, Atterberg
limits, and those determinations needed for specific designs (e.g., thick-
ness and slope determinations for single and secondary soil liners). The
following section describes the inspection activities that are necessary to
ensure, with a reasonable degree of certainty, that a soil liner is con-
structed to meet or exceed the specified design. Specific tests mentioned
in this section are listed and referenced in Appendix A.
2.3.4.1 Reconstruction--
Reconstruction CQA activities include inspection of liner materials
and test fill compaction.
2.3.4.1.1 Material inspection—It is necessary to inspect all liner
materials to ensure that they are uniform and as specified. Material
inspection begins as a preconstruction activity and continues throughout
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the liner construction period. If liner material is obtained onsite, the
inspections can be accomplished as it is placed in the storage pile with
unsuitable material being rejected. If liner material is obtained offsite,
inspection of the soil may be conducted as it arrives at the construction
site. Borrow area inspection also may be desirable to ensure that only
suitable soil liner material is transported to the site, for borrow areas
containing nonuniform materials, it may be necessary for an inspector to
guide excavating equipment to avoid or segregate substandard soil material
as it is excavated. The inspector should observe segregation operations
carefully and continuously to ensure that only suitable material is retained
for liner construction.
Initial inspection of the soil can be largely visual; however, the
inspector must be experienced witn visual-manual soil classification tech-
niques. Changes in color or texture can be indicative of a change in soil
type or soil moisture content. The soil also should be inspected for
roots, stumps, and large rocks. In addition to observations, a sufficient
number of samples of the liner material should be tested to ensure that
material properties are within the range stated in the specifications.
Testing should include at least the following:
Permeability
Soil density/moisture content relationships
Maximum clod size
Particle size distribution
Atterberg i innts
Natural water content
Potential volume change
Susceptibility to frost damage.
The number of determinations for1 each property depends on site-specific
conditions (e.g., c?oi 1 type) familiarity with the site, and the previous
experience of the construction contractor. Usually a minimum number of
tests per lift and per unit volume of liner material is specified, with
additional tests being required by the inspector if visual observations
indicate that the borrow material may have changed. See Section 2.4 for
more information on sampling requirements.
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2.3.4.1.2 Test fill construction—A test fill is a structure used to
verify the adequacy of the materials, design, equipment, and construction
procedures proposed for the soil liner. Constructing a test fill before
full-scale facility construction can minimize the potential dangers and
expense of constructing an unacceptable liner. In addition, the test fill
is a convenient tool for evaluating the most critical performance standard
of the compacted soil liner—field permeability.
The primary purpose of a test fill is to verify that the specified
soil density/moisture content/permeability values can be achieved consist-
ently in the full-scale facility with the full-scale compaction equipment
and procedures. For these data to be useful, test fill compaction and
testing must be well documented, and soil materials, procedures, and equip-
ment used in the test fill must be the same as those used during construction
of the full-scale facility.
Several recent studies have indicated that field permeability of a
compacted soil liner may be much greater than would be predicted from
laboratory permeability tests (Herzog and Morse, 1984; Gordon and Huebner,
1983; Daniel, 1984; Boutwell and Donald, 1982). Field tests have been
found to be much more accurate predictors of the rate at which water will
drain through a soil liner than laboratory tests. When used in conjunction
with these field tests and a detailed CQA plan, a test fill allows the
performance of the full-scale facility to be predicted with the highest
degree of confidence currently practical.
Recently, several field infi1trometers have been developed and tested
that measure very low permeability values (Day and Daniel, 1985; Anderson
et al., 1984). Although it is difficult to quantify exactly field permea-
bility values that are substantially less than 1 x 10 7 cm/s (Anderson
et al., 1984), it is less difficult to verify simply that the field permea-
bility is 1 x 10 7 cm/s or less (Day and Daniel, 1985). Such a verifica-
tion would demonstrate that a soil liner meets or exceeds the EPA performance
standard.
Field permeability tests conducted on the actual liner can cause
substantial delays in construction and result in other problems caused by
the prolonged exposure of the liner. Therefore, field permeability tests
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are usually conducted only on the test fill, thus making it necessary to
use data obtained from detailed characterization of the test fill to reach
conclusions about the permeability of the full-scale facility soil liner.
Such field tests are valid only if the test fill and full-scale facility
are constructed according to the same specifications and using the same
methodology and equipment.
The CQA plan should describe all observations and tests to be evaluated
on the test fill, including a description of the testing sample arrays and
replications to be conducted. Based on the parameters evaluated and data
collected from the test fill, the CQA plan should specify the tests that
will be applied to the full-scale facility liner as surrogates for actual
in situ permeability tests. Surrogate tests are a group of tests that do
not actually measure field permeability but whose results, when considered
together, can be used to estimate field permeabi1ity and hence can be used
to control this parameter during low-permeability soil liner construction.
If surrogates for field permeability tests are to be used with a high
degree of confidence, data obtained from test fill evaluation need to show
the relationships between the actual measured permeability of areas and
lifts across the test fill and the proposed surrogate test results. The
CQA plan should describe in detail the actual surrogate observations and
tests (including, at a minimum, permeability of recompacted soil samples,
Atterberg limits, particle size distribution, maximum clod size, in situ
moisture content, soil density, compactive effort, and penetrometer tests)
to be used to control and monitor the construction of the full-scale facility
liner and the procedures to be used to relate the results of these tests to
field permeability of the liner, both in the test fill and in the full-scale
facility.
For the test fill to accurately represent the performance of the
proposed full-scale facility, the following guidelines should be followed:
Construction of the test fill should use the same soil
material, design specifications, equipment, and procedures
proposed for the full-scale facility.
All applicable parts of the CQA plan should be followed
precisely to monitor and document test fill construction and
testing.
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The test fill should be constructed at least four times
wider than the widest piece of construction equipment to be
used on the full-scale facility (Figure 2-1). This is to
ensure that there will be sufficient area to conduct all
testing after a buffer area has been left along the edges of
the test fill.
The test fill should be long enough to allow construction
equipment to achieve normal operating speed before reaching
the area within the test fill that will be used for testing
(Figure 2-1).
The test fill should be constructed with at least three
lifts to evaluate the methodology used to tie lifts together.
The test fill should be constructed to facilitate field
permeability testing (i.e., equipped with an underlying
unsaturated sand layer or free-draining geotextile to collect
and measure drainage through the soil liner [Figure 2-2]).
Undisturbed samples of the test fill liner should be collected
for laboratory permeability tests. Following collection of
undisturbed samples from the test fill, the methodology for
repairing holes in the soil liner should be evaluated. The
evaluation of a repair area should include all of those
tests previously identified for undisturbed portions of the
test fill. The methods and materials that will be used in
the repair process should be documented in the CQA plan and
should be followed during repair of testing or sampling
holes during full-scale liner construction. Performance of
repaired soil liner sections should be equal to or exceed
the performance of other liner sections.
The test fill construction should include the removal and
replacement of a portion of the soil liner to evaluate the
method proposed for repair of defective portions of the
full-scale liner.
The test fill should be constructed to allow determination
of the relationship of and density/moisture content/permea-
bility values to the following:
the compaction equipment type, configuration, and
weight
the number of passes of the compaction equipment
for sheepsfoot rollers, the drum diameter and length,
empty and ballasted weight, length and face area of
feet, and the yoking arrangement (U.S. Army 1977)
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ro
CO
At least three lifts of compacted soil
A drainage layer or underdrainage collection system
Roller Type Equipment
L = Distance required for construction equipment to reach normal operating speed
W = Distance at least four times wider than the widest piece of construction equipment
wM = Area to be used for testing
Figure 2-1. Schematic of a test fill.
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Backfill
Three lifts of compacted soil
Sand Drainage Layer
Perforated Drainage
Collection Pipe
Figure 2-2. Schematic of a test fill equipped to allow quantification of underdrainage.
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for rubber-tired rollers, the tire inflation pressure,
spacing of tires, and empty and ballasted wheel loads
(U.S. Army 1977)
the method used to break down clods before compaction
and the maximum allowable clod size
the method used to control and adjust moisture content,
including equilibration time, and the quality of water
to be used in any adjustment
the speed of the compaction equipment traveling over
the liner
the uncompacted and compacted lift thicknesses.
Additional test fills should be constructed for each borrow source and
whenever significant changes occur in the liner material, equipment, or
procedures used to construct the soil liner.
The CQA officer and the inspection personnel should monitor and thor-
oughly document construction and testing of the test fill. Test fill
documentation is extremely important because it provides all organizations
involved in facility construction with a complete description of the con-
struction equipment and procedures to be used during full-scale facility
construction. For a discussion of items to be documented and documentation
procedures, see Section 2.5.
2.3.4.2 Construction--
When construction of the full-scale facility liner begins, questions
should not remain about either how or with what materials the liner will be
constructed. The suitability of the selected liner material and the adequacy
of the construction equipment, construction methodology, and testing proce-
dures will have been confirmed in the test fill. The most important remain-
ing task necessary to construct a soil liner that meets or exceeds the
specified design will be to adhere strictly to the materials, equipment,
and procedures as verified in the test fill.
There are a number of ways that improper construction practices can
result in a soil liner that is unacceptable. Guidelines to identify and
correct these improper practices in the field should be provided in the CQA
plan. These guidelines should include a combination of both continuous
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observation by an inspector during all periods and phases of liner-related
construction activity and frequent use of the tests mentioned in Sections
2.3.4.1.1 and 2.3.4.1.2. Specifically, the CQA plan should address the
following:
Procedures and methods for observing and testing the soil
liner materials before and after placement to ensure the
following:
removal of roots, rocks, rubbish, or off-spec soil from
the 1iner material
identification of changes in soil characteristics
necessitating a change in construction specifications
adequate spreading of liner material to obtain complete
coverage and the specified loose lift thickness
adequate clod size reduction of liner material
adequate spreading and incorporation of any certified
amendments to obtain the specified amount uniformly in
the amended liner material
adequate spreading and incorporation of water to obtain
full penetration through clods and uniform distribution
of the specified water content
procedures to be followed to adjust, the soil moisture
content in the event of a significant prolonged rain
during construction
prevention of significant water loss before and after
compaction.
Procedures and methods for observing and testing the soil
liner compaction process to ensure the following:
use of compaction equipment of the same type, configura-
tion, and weight as used in the test fill
use of the same equipment speed and number of equipment
passes for compaction as used in the test fill
uniformity of coverage by compaction equipment, especially
at fill edges, in equipment turnaround areas, and at
the tops and bottoms of slopes
consistent achievement of the specified soil density/water
content/compactive effort throughout each completed lift
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consistency of permeability values obtained for undis-
turbed soil liner samples with values obtained for
undisturbed samples from the test fill. Undisturbed
sample locations should be staggered from lift to lift
so holes do not align vertically.
repair of penetrations or holes resulting from the
collection of undisturbed soil samples or the use of
density or moisture probes using the same materials and
methods used for repairs on the test fill
use of methods sufficient to tie liner lifts together
achievement of sufficient liner strength to maintain
stable sidewalls and to supply a stable base for support-
ing overlying materials
timely placement of protective covers to prevent desicca-
tion of liner material between the installation of
lifts or after completion of the liner (where necessary)
prevention of accidental damage of installed portions
of the soil liner by equipment traffic
achievement of the specified permeability on the soil
liner sidewalls.
To ensure the above, it is necessary for the inspection staff to
observe the compaction process (including estimation of compactive effort)
continuously and to test the compacted liner at specified intervals using
specified tests (see Sections 2.3.4.1.1 and 2.3.4.1.2). The plan for
conducting these tests, including frequency and location, should be described
in detail in the CQA plan. Section 2.4 discusses methods for determining
sampling frequency and location as well as methods for using test data to
determine whether to accept or reject a block of work. Regardless of the
methods used in the development of sampling requirements, they should be
clearly and completely described in the CQA plan, along with the rationale
for using them. The sampling requirements also should be described on the
following basis:
Per lift and completed liner section
Per unit volume of liner material
Per unit surface area of a lift and completed liner section.
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The compaction process is affected by climate. Construction specifi-
cations often place restrictions on work performed during and just after a
rainfall, during very hot or windy conditions, or during freezing weather.
For clay soil, wet or freezing weather can alter the soil water content to
the point that close control of the compaction process may not be possible.
Movement of the construction equipment may be severely affected. As soil
temperature falls, more compactive effort must be applied to achieve the
same density. Freezing can alter soil structure, causing sloughing of
liner materials on the sidewalls or an increase in permeability. In very
dry weather, the water content of each surface fill layer can also be
altered in a very short time by drying, making continuous watering and
blending necessary. Atmospheric conditions should be observed and recorded
by the inspector, and appropriate actions should be taken when unsuitable
weather conditions exist.
Inspection activities during the construction of low-permeability soil
liners will help ensure, with a reasonable degree of certainty, that the
facility meets or exceeds the design criteria, plans, and specifications by
preventing, detecting, and correcting the following:
Regions of higher-than-specified liner permeability caused
by the use of unspecified materials, inadequate moisture
control, insufficient compactive effort, failure to fill
test holes properly, or construction during periods of
freezing temperature
Less-than-specified liner thickness or coverage from failure
to observe, monitor, and control soil placement and compaction
operations
Partings between liner lifts from failure to scarify and
control moisture in adjacent lifts
Leaks around designed liner penetrations resulting from
improper sealing and compaction
Erosion or desiccation of the liner from failure to provide
protective cover when construction is interrupted or after
liner completion.
2.3.4.3 Postconstruction--
Al1 observations and tests conducted on the test fill should be con-
ducted on the completed soil liner (i.e., the uppermost lift). Immediately
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before placement of any protective cover, the soil liner should be inspected
for cracks, holes, defects, or any other features that may increase its
field permeability. All defective areas should be removed. If the under-
lying foundation is defective (soft or wet), then this material also should
be removed and the resultant volume should be replaced. Excavated areas of
the soil liner should be repaired by the method verified during test fill
construction. Special attention should be paid to the final inspections of
the sidewall and bottom slopes, liner coverage, liner thickness, and the
coverage and integrity of the cover placed over the liner. The completed
liner should be protected from both desiccation, erosion, and freezing
immediately following completion of the uppermost lift.
2.3.5 Flexible Membrane Liners
The purpose of a flexible membrane liner (FML) in a hazardous waste
land disposal facility is to prevent the migration of any hazardous constit-
uents through the liner during the period that the facility is in operation,
including a 30-year postclosure monitoring period, and to allow no more
than d_e minimi's infiltration of waste constituents into the liner itself.
In addition, FMLs should be resistant to the waste liquid constituents that
they may encounter and be of sufficient strength and thickness to withstand
the forces expected to be encountered during cor'truction and operation.
This section describes the inspection activities necessary to ensure,
with a reasonable degree of certainty, that an FML will meet or exceed all
design criteria, plans, and specifications. Specific tests mentioned in
this section are listed and referenced in Appendix A.
2.3.5.1 Preconstruction--
Preconstruction activities for FMLs include inspection of the raw
materials, manufacturing operations, fabrication operations, and final
product quality; observations related to transportation, handling, and
storage of the membrane; inspection of foundation preparation; and evalua-
tion of the personnel and equipment to be used to install the FML. These
activities are discussed in the following subsections.
2.3.5.1.1 FML manufacture—Quality assurance for FML manufacture
should begin with the testing of the polymer raw materials. The supplier
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will generally provide documentation confirming that the raw materials
comply with the manufacturers' product properties and performance require-
ments. However, the manufacturer and the hazardous waste land disposal
facility CQA officer also should inspect the polymer raw materials. The
specific observations and tests that these individuals may make, depending
on the type of raw materials being supplied, include (adapted from Knipschild
et al., 1979):
Density. This property gives an indication of the material's
molecular structure and degree of crystal 1inity, which can
be related to mechanical properties such as strength and
deformation.
Melt Flow Index. The constancy of this property within
narrow tolerance ranges ensures consistent molecular weight
and rheological properties for high density polyethylene.
Knowledge of the value for this property is also helpful
when selecting production process parameters.
®
Relative Solute Viscosity For Hypalon . The value of this
property indicates a polymer's mean molecular weight and its
degree of polymerization. These properties affect consistency
of processing and the finished product's physical properties.
®
Percent Volatile Components For Hypalon . This test gives a
value for the moisture content of the raw material. It is
important to control this factor to ensure that a product is
free from bubbles and pores.
Percent Carbon Black. Constant control of the amount and
distribution of carbon black in the resin is important to
ensure protection against UV radiation.
Additional inspections of polymer raw materials may be required by the
site-specific CQA plan. These additional tests would be dependent upon the
type of polymer being supplied and the environment to which it will be
subjected.
Other types of raw materials that may be used in the production of
specific membrane types include additives and reinforcing materials. These
types of materials should be manufactured under the vendor's quality control/
quality assurance program and a certification indicating that they meet the
performance specifications should be provided. These additives should also
be inspected to confirm that they are the materials that were requested and
that they were packaged, labeled, and shipped as specified to prevent damage.
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The compounding ingredients used in producing membrane liners should
be first quality, virgin material meeting specific public health and safety
requirements as well as providing durable and effective formulations for
liner applications. Clean rework materials containing encapsulated scrim
or other fibrous materials should not be used in the manufacture of FMLs.
Clean rework materials of the same virgin ingredients generated from the
manufacturer's own production may be used by the same manufacturer, provided
that the finished products meet the product requirements.
Each manufacturer should have a manufacturing quality management
program based on the manufacturing method used and the type of membrane
being produced. The hazardous waste land disposal facility CQA officer
should obtain a copy of and review the manufacturer's construction quality
assurance program. This review should include a visit to the production
plant. If there are areas where the CQA officer feels the manufacturer's
construction quality assurance program is weak, he may request that the
manufacturer conduct additional tests. The CQA officer may also conduct
more tests to verify the manufacturer's product specifications.
The completed FML also should be tested by both the manufacturer and
the hazardous waste land disposal facility CQA personnel. This phase of
CQA is necessary to confirm that the final product meets the liner perform-
ance specifications. Examples of finished product specifications that may
be tested for various liner types include (Eorgan, 1985; VanderVoort,
1984):
Thickness
Tensile properties
Tear resistance
Puncture resistance
Density
High temperature
Low temperature
Dimensional stability
Resistance to soil burial
Stress crack resistance
Oil absorption
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Ozone resistance
Heat aging
Volatility loss
Percent carbon black
Ultraviolet (UV) resistance
Chemical resistance
Specific gravity
Percent swell
Ply adhesion
Scrim characteristics
Hardness.
Several of the more commonly used physical property test methods are listed
in Appendix A and Section 2.3.5.2 of this document as well as in Table VIII-1,
p. 407, of "Lining of Waste Impoundment and Disposal Facilities" (EPA-SW-870,
1983) and in Standard Number 54 (NSF, 1983).
To ensure that the material that was approved in the chemical compati-
bility test is the material that was delivered to be installed, it should
be identified by an appropriate "fingerprint." (Morrison et al., 1982;
Haxo, 1983; NSF, 1983.) Samples should be obtained and tested from each
shipment received at the job site. The shipment should be rejected if the
product is not consistent with what was originally approved.
The FML manufacturer and CQA officer should retain a sample of the
finished liner from each of the raw material batches for future reference.
If problems with the FML occur, it would then be easy to trace the material
to the specific batch.
Some FML types require factory seaming before shipment to the con-
struction site. This allows for smaller liner sections to be seamed into
panels or blankets, which will then require fewer field seams. Blankets or
panels should be assembled from roll goods according to the designer's
field layout. Any changes should be approved by the designer and the
owner/operator. Personnel performing the factory seaming and other duties
should be under the supervision of a master seamer. The factory seam
should be of equal or better quality than that described in Section 2.3.5.2.2.
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Generally, seaming should be performed only when the ambient air
temperature is between 40 and 100 °F and the relative humidity is less than
70 percent. However, the FML manufacturer should be consulted on recommended
temperature and humidity specifications for the specific liner type. The
seaming environment should be clean, and good housekeeping should be prac-
ticed.
The CQA officer should evaluate the factory seams to ensure that the
seam overlap is as specified and that the proper seaming procedure was
used. The seams should be 100 percent nondestructively evaluated using
recommended techniques (Mitchell and Spanner, 1984). Rejected seams should
be fully documented and repaired. The CQA officer should destructively
test at least two factory seam samples per blanket. Samples should be
taken in such a way that the blanket integrity is not damaged and the
layout pattern is not altered. Repairs to the blanket should be in accord-
ance with approved techniques and the repaired areas should be nondestruc-
tively tested to verify their integrity.
2.3.5.1.2 FML transportation and storage--FMLs are usually shipped in
rolls or folded on pallets. When rolls are used, the inspector should
confirm that the FML has been protected with some type of covering material;
often a thick sheet of the same material as the membrane is used. When the
membrane is folded on pallets, it should be placed in heavy cardboard or
wooden crates before its shipment. The roll or pallet of finished materials
should be marked to show the following minimum information (adapted from
Schmidt, 1983):
Name of manufacturer/fabricator
Product type
Product thickness
Manufacturing batch code
Date of manufacture
Physical dimensions (length and width)
Panel number or placement according to the design layout
pattern
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Direction for unrolling or unfolding the membrane.
When the FML is delivered to the construction site, it should be
inspected to confirm that it is the material that was specified, (i.e.,
fingerprinted) and that it is not damaged. Inspection activities will
ensure, with a reasonable degree of certainty, that the completed facility
meets or exceeds design criteria, plans, and specifications by preventing,
detecting, and correcting the following:
Puncture from nails or splinters
Tears from operation of equipment or inadequate packaging
Exposure to temperature extremes resulting in unusable
material
Blocking: the bonding together of adjacent membrane layers,
which may be caused by excessive heat
Crumpling or tearing from inadequate packaging support.
These types of damage may be avoided by careful handling of the FML during
preparation for shipment and of the packaged crates and rolls of materials.
When damage to a crate or roll cover has occurred, careful examination
of the underlying material by an inspector is required. If damage is
found, the inspector should carefully examine the entire shipment for
damage.
Onsite storage of the synthetic membrane liner should be in a secure
area with provisions for shelter from adverse weather and be as brief as
possible. This helps avoid damage caused by the following:
UV light
Heavy winds or precipitation
Temperature extremes (i.e., loss of plasticizers in polyvinyl
chloride [PVC], curing and adhesion of adjacent surfaces of
chlorosulfonated polyethylene, and creation of permanent
folds or wrinkles in certain liner types)
Vandals.
2.3.5.1.3 Lower bedding layer placement—The observations and tests
necessary to ensure that an adequate liner lower bedding layer is provided
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are discussed in Section 2.3.2.2. When an FML is placed directly on the
bedding layer, it is extremely important to inspect the surface visually to
confirm that it is free from clods of soil, rocks, roots, sudden or sharp
changes of grade, and standing water. The inspector also should confirm
that the soil has been sterilized when necessary with an approved herbicide
using the manufacturers' recommended procedures.
In composite liner systems, the lower FML bedding is the compacted
low-permeability soil liner. If the bedding is subject to drying and
cracking, precautions should be taken by the facility owner/operator to
prevent desiccation. This prevention may be in the form of a temporary
liner (e.g., thin plastic cover) or special nonreactive chemicals. If a
temporary liner is used, the CQA officer should ensure that it is secure at
the edges and that, before the installation of the designed FML, the tempo-
rary liner is removed and any soil liner cracks are documented and repaired.
If desiccation cracks are observed, the appropriate techniques and specifi-
cations for correction should be provided in the design specifications.
2.3.5.2 Construction--
Failure of an FML can result from defective manufacturing and fabrica-
tion, improper handling and storage, or poor installation methods. The
observations and tests necessary to detect these defects during construc-
tion are discussed in the following subsections.
2.3.5.2.1 FML placement—Inspection activities that are necessary
during liner placement include (adapted from Kastman, 1984):
Checking delivery tickets and synthetic membrane manufacturers'
quality control reports to verify that the synthetic membrane
rolls received onsite meet the project specifications. [In
addition, "it is usually good practice to take the identify-
ing labels from each roll or pallet and save them for future
reference. Further, the position of each roll or pallet of
material should be noted on a final installation drawing.
This document can be used as future reference should problems
occur." (Schmidt, 1983)]. As an additional check to ensure
the quality of the product being delivered, a sample should
be taken, "fingerprinted," and that fingerprint should be
compared with the fingerprint of the product originally
contracted for.
Observations to ensure that the FML placement plan was
followed.
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Observations of the weather conditions (i.e., temperature,
humidity, precipitation, and wind) to ensure that they are
acceptable for membrane placement and seaming.
Observations and measurements of the anchor trench to ensure
that the lines and width are as specified in the design
drawings. If the trench is excavated in soil that is suscep-
tible to desiccation, only that trench length that is required
for 1 day's work should be excavated. Consideration should
be given to using a temporary liner in the trench to prevent
desiccation. Trench corners should be rounded to prevent
stressing the membrane. Good housekeeping practices should
be used in the trenching operation by not allowing any loose
soil material in the trench or on the downhill side of the
trench. Backfilling of the trench should be performed as
soon as possible and compacted with care so as not to damage
the FML.
Observations and tests to confirm that all designed liner
penetrations and liner connections are installed as specified.
Liner penetrations should be verified for appropriate clamp
and caulking use, for appropriate material, for good seaming,
and for good housekeeping practices. No sharp bends on
foundations (concrete pads) should be allowed. Soil compac-
tion adjacent to concrete pads should be performed as speci-
fied to prevent differential settlement.
Measurements to confirm that required overlaps of adjacent
membrane sheets were achieved, that proper temporary anchorage
was used (e.g., sand bags or tires), that specified temporary
and final seaming materials/techniques were used, and that
the blanket was placed in a relaxed (nonstressed) state.
As each synthetic membrane panel is placed, it should be visually
inspected for tears, punctures, and thin spots. The inspector should also
inspect any factory seams to ensure that they are adequate. To accomplish
this, the panels should be traversed by the inspector in such a way that
the entire surface, including all factory seams, is inspected. For synthetic
membranes that are fabricated from roll stock widths of about 5 feet, the
normal procedure used to detect membrane defects is to walk along each roll
stock width and inspect the entire length of the sheet. Any defects should
be marked on the synthetic membrane for repair.
The overall quality of a flexible membrane liner installation can be
affected by the weather conditions during which it was installed. The
inspector should be aware of all of these factors and the effects they may
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have on the specific membrane type and seaming procedure being used. If
the weather becomes unacceptable for installation of the liner, the inspector
should stop the membrane installation until conditions again become favor-
able, thus minimizing the potential for unacceptable installation.
Inspection activities during FML placement will help ensure, with a
reasonable degree of certainty, that the completed facility meets or exceeds
all design criteria, plans, and specifications, by preventing, detecting,
and correcting the following:
Liner damage from adverse weather conditions, inadequate
temporary anchoring, or rough handling
Improper liner placement (if the placement plan is not
followed) and, as a result, inadequate coverage with the
available materials or an excess number of field seams
Inadequate sheet overlap, possibly resulting in poor quality
seams
Nonwelded or nonseamed sections
Inadequate seam strength.
2.3.5.2.2 FML seaming—Inspection activities that should be documented
during membrane seaming operations include:
Observations to ensure that the membrane is free from dirt,
dust, and moisture
Observations to ensure that the seaming materials and equip-
ment are as specified.
Observations and tests to ensure that a firm foundation is
available for seaming
Observations of weather conditions to ensure that they are
acceptable for seaming
Measurements of temperatures, pressures, and speed of seaming,
when applicable, to ensure that they are as specified (gages,
dials, etc., should be checked and recorded)
Measurements of the curing time between seaming and seam
testing to ensure that it is as specified
Observations to ensure that the membrane is not damaged by
equipment or personnel during the seaming process.
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Inspection activities help ensure, with a reasonable degree of certainty,
that the completed facility meets or exceeds all design criteria, plans,
and specifications by preventing, detecting, and correcting the following:
Seam gaps or weak spots resulting from the presence of dirt
or dust
Less-than-specified seam strength resulting from the use of
unspecified materials, improperly operating equipment,
insufficient pressure, ambient temperature extremes, or
insufficient dwell time
Liner damage caused by cleaning or bonding solvents and
seaming equipment. Liner damage may also result from walking
on the membrane while wearing improper footwear or from the
improper disposal of cigarette butts.
After field seams are installed, they should be inspected to ensure
that a homogeneous bond was formed. Different nondestructive inspection
methods (in addition to visual observations) are available for testing
seams in the field, depending on the type of liner material being placed
(Mitchell and Spanner, 1984):
Nondestructive tests should be performed on 100 percent of
the field seams. Failed seams should be recorded as to
location and seaming crew. The data should be reviewed for
possible patterns. Repairs should be made in accordance
with approved techniques and retested to verify their integrity.
Destructive seam testing should be performed at previously
agreed to locations and frequencies. A minimum number and
location per seam length per seam crew should be established.
If different seaming techniques are used, additional test as
per seaming type should be added. Additional test locations
may be necessary at the QA officer's discretion. These
locations may be based on suspicion of contamination by dirt
or moisture, change in seaming materials, increase in failed
nondestructive tests, and other causes that could result in
unacceptable seams.
Destructive seam samples should be large enough for the
installer to check in the laboratory, for an independent
laboratory evaluation, and for site owner archiving. If
possible the seam should be destructively tested in the
field at the time of sampling (provided sufficient time has
elasped for the seam to cure properly). Proper documentation
should follow each seam sample as to location, time, crew,
technique, etc.
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Laboratory testing should be performed in accordance with
design specifications with predetermined pass/fail values.
Both peel and shear testing should be performed as suggested
by Standard Number 54 (NSF, 1983) or ASTM, for the specific
material type.
For field seams that fail, the seam can either be reconstructed
between the failed and any previous passed seam location or
the installer can go on either side of the failed seam
location (10-foot minimum), take another sample, test it and
if it passes, reconstruct the seam between the two locations.
If it fails, the process should be continued. In all cases
acceptable seams must be bounded by two passed test locations.
All repairs should be performed as soon as possible and in
accordance with the design specifications. Each repair
should be nondestructively tested for continuity. Documenta-
tion of all repairs including location, type, method used,
etc., should be made.
2.3.5.2.3 Anchors and seals installation—When a hazardous waste land
disposal unit design calls for penetrations (e.g., structures and pipes) in
the flexible membrane liner, the inspector must ensure that the seals
around such penetrations are of sufficient strength and are impermeable to
leachate. Specific inspections that should be made on all seals or anchors
include:
Observations to ensure that the materials (i.e., pipe boots
and sealing compounds) are compatible with the waste and are
as specified.
Observations and tests to ensure that the sealing systems
(i.e., pipe boots) were installed as specified (are leak
free) and in the proper locations.
Observations to ensure that all objects that may be placed
adjacent to the synthetic membrane (i.e., batten bars, soil
in an anchor trench, and concrete structures) are smooth and
free of objects or conditions that may damage the membrane.
Observations and tests to ensure that all seals and anchors
are complete (i.e., no gaps or areas of uncompacted backfill).
Inspection activities during this phase of construction will ensure,
with a reasonable degree of certainty, that the completed facility meets or
exceeds all design criteria, plans, and specifications by preventing,
detecting, and correcting the following:
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Compatibility or corrosion problems from the use of unspeci-
fied materials
Leaks around penetrations or slipping of the membrane from
incomplete seals or inadequate compaction of backfill
Flexible membrane damage from rough edges, sharp corners, or
rocks. Membrane damage can also occur from excessive stress
placed on the liner because of improper location of sealing
and/or anchoring mechanisms.
2.3.5.2.4 Upper bedding layer placement—An upper bedding layer,
often referred to as a protective cover, when required over an FML, should
be placed as soon as possible after installation to protect the FML from
weather conditions, equipment, and vandalism. The covering of the FML,
while important and necessary, should not be performed until the FML instal-
lation is completed and accepted. However, on very large jobs, it may be
necessary to have partial acceptance procedures. These can be mutually
agreed upon at the preconstruction meeting. The protective cover is usually
soil that is free of rocks, sticks, and other items that could damage the
membrane. Inspection activities that should be conducted during protective
cover installation include:
Observations and tests to ensure that the cover material
meets specifications.
Observations to ensure that the cover material is free from
objects that could damage the liner.
Observations to ensure that the equipment or procedures used
to place the cover material do not puncture or tear the
synthetic membrane.
Measurements to ensure that the entire liner is covered with
the specified thickness of cover material.
There are a few standard checks and test methods that can be used, in
addition to visual observations, to ensure that a flexible membrane liner's
protective cover is installed according to the specified design. These
checks include surveying using conventional or laser/electronic instruments
to ensure that the layer thickness is as specified. The thickness of the
cover layer can also be monitored simply by measuring it with a marked
measuring staff. When this method is used, the inspector must ensure that
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the staff does not puncture the underlying liner. The bedding layer soil
type may be inspected by using visual-manual soil identification techniques
and index property tests. These test procedures are briefly discussed in
Section 2.3.4.1.1 and are listed and referenced in Appendix A.
Inspection activities during upper bedding layer placement will ensure,
with a reasonable degree of certainty, that the completed facility meets or
exceeds all design criteria, plans, and specifications by preventing,
detecting, and correcting the following:
Liner damage from the use of unspecified materials, equipment
or human traffic, or weather conditions
Insufficient upper bedding layer thickness or coverage.
2.3.5.3 Postconstruction--
Upon completion of flexible membrane liner installation and seam
testing, but prior to placement of the upper bedding layer, the liner
should undergo a thorough visual inspection for any damage that may have
occurred during installation. If any damaged areas are located, they
should be marked and patched using approved repair methods. These patched
areas should be nondestructively tested to ensure that they do not leak.
To check for leaks in the installed membrane liners of small landfills
or surface impoundments, the facility can be filled or partially filled
with water and seepage from the site measured after accounting for evapora-
tion. This method is often combined with leachate collection system (LCS)
testing and, when feasible, is the best way to ensure that the synthetic
liner will function according to specifications after it is put into service,
assuming that no waste/liner compatibility problems occur. In the case of
double liner systems, this type of testing will be more complex because of
the presence of two LCSs.
If the waste facility shows evidence of leakage after filling with
water, the leak(s) must be located, repaired, and retested before the facil-
ity can be accepted. Several techniques, including tracer dyes and electri-
cal resistivity, could be used to locate the leak(s).
2.3.6 Leachate Collection Systems
The purpose of a primary LCS in a landfill is to minimize the leachate
head on the top liner during operation and to remove liquids from the
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landfill through the postclosure monitoring period. The LCS should be
capable of maintaining a leachate head of less than 1 foot. The purpose of
a secondary LCS (leak detection system) between the two liners of a landfill
or surface impoundment is to rapidly detect, collect, and remove liquids
entering the system through the postclosure monitoring period.
The following sections describe the CQA inspection activities necessary
f
to ensure, with a reasonable degree of certainty, that a completed LCS meets
or exceeds all design criteria, plans, and specifications. Specific tests
referred to in the following sections are listed and referenced in Appendix A.
2.3.6.1 Preconstruction--
Preconstruction activities for a leachate collection system include
inspection of all materials and examination of the LCS foundation.
2.3.6.1.1 Material inspection—Observing all LCS subcomponent materials
as they are delivered to the site is necessary to confirm and document that
these materials conform to the design criteria, plans, and specifications.
To accomplish this, inspection activities should include the following:
Observations to ensure that all synthetic drainage layers
and/or geotextiles meet the design specifications.
Observations and measurements to ensure that the pipes are
of the specified size and strength, are constructed of the
specified material, and that pipe perforations are sized and
spaced as specified.
Observations and tests to ensure that the soils to be used
in the LCS are of the proper size and gradation, do not
contain unspecified types of materials, and that specified
provisions to keep LCS soils clean during storage, handling,
and placement are followed.
Observations to ensure that all prefabricated structures
(e.g., manholes and sumps) are as specified in the design.
This should include inspection of any corrosion-resistant
coatings to confirm that they are present and without flaws.
Observations of all mechanical, electrical, and monitoring
equipment to ensure that it is as specified in the design.
In some cases (e.g., pumps), the specific pieces of equipment
can be tested to ensure that they are operational.
Observations and tests to ensure that, when concrete struc-
tures are to be installed, the raw materials supplied and
necessary forms are as specified in the design.
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Testing of the soil materials includes visual-manual classification, grain
size distribution tests, and permeability tests to ensure that proper soil
types are used for specific applications.
2.3.6.1.2 Foundation preparation—An examination of the foundation
for the leachate collection system should be performed before construction.
In the case of double liner systems, the bedding for both primary and
secondary leachate collection systems will be an FML or a low-permeability
soil liner depending on the type of facility. Inspection activities should
include:
Measurement of the horizontal and vertical alignment of the
foundation to ensure that leachate will flow toward the
sump.
Observation of the foundation to ensure that it is free of
debris and liquids that would tend to interfere with construc-
tion of the leachate collection system.
2.3.6.2 Construction--
A leachate collection system is composed of many separate subcompo-
nents. Each of these subcomponents must be installed as specified in the
design to ensure proper facility function. The following subsections
include discussions of observations and tests that should be performed for
each leachate collection system subcomponent.
2.3.6.2.1 Bedding layer placement—To avoid damage to the foundation
of the LCS, a bedding layer may be placed before pipe network installation.
The bedding layer may be either a granular or manufactured material (i.e.,
geotextile). Inspection activities that should be performed include:
Observation of the bedding material to ensure that it is as
specified and that it does not contain objects that would
damage or alter the underlying foundation
Measurement of the thickness of the bedding layer to ensure
uniformity of layer depth
Observation of the areal coverage of the bedding layer to
ensure that it is the same as that specified in the design.
When manufactured materials are used, it should be verified
that sheets are joined or connected as specified in the
design.
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These observations and tests are necessary to ensure that the materials in
the bedding layer do not damage the foundation.
2.3.6.2.2 Pipe network installation—The pipe network should be
placed according to the specified design. Inspection activities that
should be performed during pipe placement and joining include:
Observations and measurements to ensure that the pipes are
placed at specified locations and in specified configurations
Observations and tests to ensure that all pipes are joined
together as specified
Observations to ensure that the placement of any filter
materials around the pipe proceeds as specified in the
design
Observations and tests to ensure that backfilling and compac-
tion are completed as specified in the design and that, in
the process, the pipe network is not damaged.
Adequate CQA during this phase of LCS construction will prevent, detect,
and correct the following:
Clogging of the LCS pipes or sections of the pipes from the
improper installation of filter materials or from construction
runoff
Inadequate LCS function from the improper joining of pipes,
from the improper placement of pipes, or from mechanical
damage to the pipe network.
If the pipes are not adequately protected from fine particle accumu-
lations during the construction phase, it may be necessary to flush the
pipe network upon completion to remove sedimentation and debris and to
verify that the line is open. Standard sewer cleaning equipment can be
used to remove objects and debris remaining after simple flushing. If this
equipment is unable to pass through the line, it may mean that a section of
pipe has been crushed or displaced.
Testing of solid pressure and nonpressure LCS pipes should also be
conducted to check for leaks and the structural integrity of the solid pipe
network. No standardized test procedures are available to perform the test
for nonpressure pipes. The American Water Works Association has developed
a method for testing solid pressure pipes (AWWA, 1982).
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In some cases, it may be desirable to look at the interior of the pipe
to verify its alignment and to confirm that there are no obstructions or
debris in the pipe. The procedure consists of pulling a television camera
mounted on skids through the pipe and recording the distance from the
starting point as the camera moves. The location of any problem can be
found by measuring the distance from the starting point. In the case of
the leachate transport pipe, this procedure can be used to identify sources
of infiltration.
2.3.6.2.3 Drainage layer placement--
Granular drainage layers—Granular LCS drainage layers are constructed
of clean, inorganic, free-draining, granular soils such as sand and gravel.
These soils are selected before their use in the LCS on the basis of their
grain size distribution.
Some or all of the soil drainage layer may be placed before or after
pipe placement. To ensure the quality of this drainage layer, inspectors
should:
Test the soil to ensure that it is of the specified permeabil-
ity and grain size and free from excessive amounts of fines
or organic materials
Measure the thickness and observe coverage of each drainage
layer lift as it is placed in the LCS
Observe the compaction process and test the compacted layer
to ensure its adequacy
Survey the completed layer to ensure that specified grades
are obtained
Observe that the transport of fines by runoff into the LCS
is prevented by barriers or filters.
When pipe placement precedes granular soil placement, it is also necessary
to monitor soil placement and compaction operations to ensure that the LCS
pipes are not damaged or moved by the installation equipment.
Adequate CQA inspections during granular drainage layer placement will
help ensure the integrity of the entire facility by preventing, detecting,
and correcting the following:
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Areas of lower than specified drainage layer permeability
resulting from the use of unspecified materials or from
fines that enter and clog the system
Less-than-specified layer thickness or coverage
Damaged and misaligned pipes.
There are several standardized test methods that may be used to monitor
the drainage layer materials, placement, and compaction. The material type
should be monitored using the methods discussed in Section 2.3.6.1.1. A
method for determining the permeability of the installed drainage layer,
along with the previously mentioned test methods, is listed and referenced
in Appendix A.
Synthetic drainage layers—There are three main types of synthetic
drainage materials available for use in leachate collection systems: nets,
mats, and geotextile fabrics. These synthetic drainage materials may be
used alone or in combination with granular drainage layers to form the LCS
for a hazardous waste land disposal facility. For more information on
synthetic drainage layer design and construction, see E. C. Jordan Co.
(1984).
Prior to the placement of geotextiles or synthetic drainage materials,
an inspector should confirm that these materials are as specified and have
not been damaged due to shipping or improper storage. Several standardized
tests are available to evaluate specified properties of geotextiles. These
include tensile strength, puncture or burst resistance, tear resistance,
flexibility, outdoor weatherabi1ity, and short-term chemical resistance.
For more information on these test methods, including discussions on their
applicability, limitations, and proper interpretations, the reader is
referred to Horz (1984). Appendix B of Horz (1984) also contains detailed
test procedures for fabric permeability and percent open area. There are
currently no published standard test methods for either of these properties.
An inspector also should verify that the surface on which the synthetic
drainage layer or geotextile is to be placed has been prepared properly.
This may include surveying the slope or grade, inspecting material type
and compaction for soils, or inspecting flexible membrane seaming and
anchoring.
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During the installation of a synthetic drainage layer or a geotextile,
the inspector should perform the following inspection activities:
Observations to ensure that the materials are placed according
to the placement plan
Measurements to ensure that the specified material overlap is
achieved
Observations to ensure that the material is free from wrinkles
and folds
Observations to ensure that, when specified, the edges of
geotextiles are coated to prevent wieking
Tests, when required, to ensure that seams are made according
to the design specifications
Observations to ensure that weather conditions are appropriate
for placement and that the exposure of the synthetic drainage
layers or geotextiles to rain and/or direct sunlight during
and after installation is minimized
Observations to ensure that the material is not damaged
during the installation process
Observations to ensure that barriers or filters are installed
to prevent clogging of drainage layers from fine particles
in construction runoff.
Inspection activities during synthetic drainage layer placement will help
ensure, with a reasonable degree of certainty, that the completed facility
meets or exceeds the design criteria, plans, and specifications by prevent-
ing, detecting, and correcting the following:
Geotextile or synthetic drainage layer slippage resulting
from improper placement or seaming
Stress damage to the material from improper placement
Improper material function because of wrinkles in the material,
inadequate seam overlap, improperly made seams, inadequate
coating of the material's edge, clogging of the material by
fine particles, or damage to the material from weather
conditions, human traffic, or equipment.
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2.3.6.2.4 Filter layer placement—The filter layer subcomponents of
an LCS may be constructed of granular soils or synthetic materials. In
both cases the materials used in the filter layer are selected before
construction as part of the facility design criteria, plans, and specifica-
tions.
Soil filter layers--LCS soil filter layer placement quality is checked
in much the same way as that for granular drainage layers; observations and
tests that should be performed and recorded include:
Soil tests to ensure that it is of the specified grain size
and free of excessive amounts of fines or organic materials
Observations of the placement process to ensure that it is
performed as specified
Measurements of the thickness of the filter layer to ensure
that it is as specified.
These observations and tests are necessary to ensure that areas of the LCS
do not become blinded or clogged by fine particles infiltrating the system.
If this occurs, the LCS will not function properly and leachate levels in
the facility may exceed regulatory requirements.
Synthetic filter layers—Geotextiles are synthetic products specially
designed to have good drainage and strength characteristics. Geotextile
filter layers will retain fine material that is contained in the leachate
while allowing the flow of liquids to the drainage layer and collection
pipes. In this application, the geotextile protects the drainage layer and
pipe system from becoming clogged.
Inspection activities that should be conducted during the placement of
a geotextile filter layer include:
Tests to ensure that the geotextile permeability and effective
opening size are as specified
Observations of geotextile placement to ensure that the
specifications are followed, including coverage of all
specified areas and adequate material overlap or seaming
Observations to ensure that the completed geotextile filter
layer or any other system subcomponent is not damaged during
placement.
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These observations and tests are necessary to ensure that the LCS does not
become clogged.
2.3.6.2.5 Sumps and associated structure installation—Sumps and
manholes can be manufactured offsite and delivered to the site ready for
installation as part of the LCS. The design engineer will usually specify
that, at a minimum, the supplier should furnish certification with appro-
priate documentation that the structures have been fabricated according to
the design engineer's specifications. Additional inspection of precast
concrete, steel, and fiberglass structures may be needed to confirm the
identity and quality of manufactured structures. Inspection activities
that should be performed include:
Observations to ensure that the structures were not damaged
during shipment
Measurements to ensure that the structures are of the speci-
fied dimensions and capacity
Observations to ensure that the structures are made of the
specified materials
Observations to ensure that any corrosion-inhibiting coatings
are free from defects such as flaking, scratches, or blisters.
If defects are present, manufacturers' specifications for
repair should be available.
These observations and tests are necessary to ensure that LCS structures
are constructed of specified materials, are of adequate size, and are not
damaged. If any of these situations occur, the LCS may not function properly.
Visual observations of manhole and collection tank installation are
necessary to ensure that the components are installed as specified in the
design and that they are not damaged during the process. Installation of
the footings or foundations for these structures also should be observed to
ensure that damage to the liner is prevented. Surveying should be performed
to confirm that all structures are installed in the proper locations.
In the event that manufactured structures are not appropriate, cast-
in-place concrete structures may be constructed. The installation of
concrete structures, such as manholes and collection tanks, requires visual
inspection of the installation, including cast-in-place procedures, and
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tests of the concrete that is cast at the LCS site. Observations that
should be made include:
Inspection of formwork to ensure that it is complete and has
the specified dimensions
Inspection of concrete placement operations
Inspection of the curing process to ensure that a satisfactory
moisture content and favorable temperature are maintained.
These inspection activities are necessary to ensure that the resulting
structure is of the specified size and strength.
Design specifications for concrete will usually require testing of the
type, quality, and gradation of the aggregates; the consistency and air
content of fresh concrete; and specimens of the concrete for strength.
Grain size distribution tests and visual-manual classification are usually
required for the aggregates before their use. Consistency, or slump, of
the concrete should be determined to ensure that it conforms with the
design specifications. The air content of the freshly mixed concrete can
be determined by the pressure method. The compressive strength of samples
of concrete can be determined using the strength test.
2.3.6.2.6 Mechanical and electrical equipment instal lation—Instal 1a-
tion of mechanical equipment such as pumps, valves, motors, liquid-level
monitors, and flowmeters is usually the final activity during LCS construc-
tion. The CQA inspections that should be performed include:
Observations of all mechanical equipment installation to
ensure that it is in accordance with the design specifications
and manufacturer's recommendations
Testing of all mechanical equipment in accordance with
manufacturers' instructions and operations manuals.
Authorized service representatives of the manufacturers
may be present to provide any necessary assistance.
These observations and tests are necessary to ensure, with a reasonable
degree of certainty, that the facility meets or exceeds all design criteria,
plans, and specifications. This will reduce the possibility of equipment
failure and leachate head buildup in the LCS.
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Inspection of electrical connections for mechanical equipment should
be performed by personnel certified by national and/or State licensing
agencies to perform electrical work. The visual observations necessary for
electrical equipment are the same as those previously discussed for mech-
anical and monitoring equipment. CQA testing should focus on four major
areas: insulation, grounding, equipment, and control circuits.
2.3.6.3 Postconstruction--
Postconstruction inspection of a leachate collection system should
include:
Observations to ensure that all system subcomponents have
been installed in the proper locations and according to
design and manufacturer's specifications
Testing to ensure that all pumps operate at rated capacity
and that all electrical controls and monitoring equipment
perform in accordance with the specified design.
A final performance test for a leachate collection system may be
included as part of a facility's CQA plan. This test may be conducted by
filling all or a portion of the system with a known quantity of water. The
water should then be removed from the system and its volume determined.
The volume of water remaining is the system's storage volume. If the
storage volume is significantly higher than expected, there may be areas of
the system that are not draining properly. If this is the case, the entire
LCS should be inspected to locate the areas that are not draining properly.
Corrective measures should then be implemented to ensure that specified LCS
drainage can be obtained.
2.3.7 Final Cover Systems
Final cover systems for hazardous waste land disposal facilities are
designed to provide long-term minimization of liquid migration and leachate
formation in the closed landfill by preventing the infiltration of surface
water into the facility for many years and minimizing it thereafter in the
absence of damage. Final cover systems are constructed in layers, the most
important of which are the barrier layers. Other layers are included to
protect or to enhance the performance of the barrier layers.
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The purpose of a final cover system is to provide long-term minimization
of migration of liquids through the closed landfill, control the venting of
gas generated in the facility, and isolate the wastes from the surface
environment. A final cover system must be constructed so that it functions
with minimum maintenance, promotes drainage and minimizes erosion or abrasion
of the cover, accommodates settlement and subsidence so that the cover's
integrity is maintained, and has a permeability less than or equal to the
permeability of the bottom liner system component with the lowest permea-
bility.
The following subsections describe the quality assurance activities
necessary to ensure, with a reasonable degree of certainty, that a completed
final cover system meets or exceeds all design criteria, plans, and specifi-
cations. Specific tests mentioned in this section are listed and referenced
in Appendix A.
2.3.7.1 Preconstruction--
Preconstruction activities for final cover systems include screening
incoming materials for the system subcomponents and compacting test fills
for the soil barriers. These and other preconstruction activities for each
cover system component are identified below and described in the following
sections:
Low-permeability soil barrier (Section 2.3.4.1)
Flexible membrane barrier (Section 2.3.5.1)
Drainage and venting layers (Section 2.3.6.1).
For the topsoil and vegetation components, it should be verified that
sufficient quantities of topsoil, fertilizer, soil conditioners, and seeds
are available to complete the topsoiI/vegetation cover, and that the quality
of these materials is as specified in the design. Topsoil should be charac-
terized for the required agronomic properties (Oilman et a!., 1983).
Before facility closure, it may be desirable to plant experimental
plots to verify that the proposed vegetation will be tolerant of the expected
conditions in the final cover system. Conditions that should be considered
include local climate as well as (Gilman et al., 1983):
Cover soil type, depth, and compaction
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Waste depth, type, age, and compaction
Surface slope.
2.3.7.2 Construction--
The inspection activities necessary for evaluating the quality of a
final cover system construction are addressed below by component, beginning
with the final cover foundation layer. Many of the activities are the same
as for other facility components addressed earlier; e.g., the low-permeabil-
ity barrier is much the same as the low-permeability soil liner. Inspection
activities are referenced to earlier sections as appropriate.
2.3.7.2.1 Final cover system foundation preparation—Before the
construction of the cover foundation layer or overlying cover components,
observation and tests should include an evaluation of the waste placement
records and the actual waste placement process, where possible. This
evaluation should include an estimate of the degree and uniformity of waste
placement and compaction. In the case of drummed waste, the evaluation
should ensure that drums are placed in an orderly manner and that voids
between drums are backfilled completely. The objective is to ensure maximum
and uniform compaction of the waste to minimize void spaces and to ensure
that the final cover system foundation (waste) has the specified bearing
strength. This is necessary to minimize the potential for future differen-
tial settlement or subsidence and resultant final cover system damage.
Soil materials to be used in the foundation should be observed and
tested as necessary to confirm that they meet the specified design. Mater-
ials specifications may include a maximum grain size and a requirement that
they be free of large objects that could damage or make the placement of
the overlying low-permeability soil barrier difficult. The construction
materials of any subcomponents that are to be installed with their bases
in waste or in the foundation layer (e.g., gas vents) should be inspected
for conformance to design specifications.
The construction of the final cover system foundation should be tested
to determine thickness, surface slope, density, particle size, and permea-
bility. Design requirements may be more restrictive around standpipes,
vent pipes, and the perimeter of the fill area. In the perimeter area, the
cover subcomponents must join the liner subcomponents through a relatively
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complex design. The CQA officer should be especially cognizant of the
perimeter design requirements and the measurements necessary to ensure that
these requirements are met.
2.3.7.2.2 Low-permeability soil barrier placement—The low-permeability
soil barrier provides a base for the flexible membrane barrier subcomponent
of the final cover system and provides long-term minimization of liquid
infiltration. It serves as a secondary barrier to infiltration in case the
flexible membrane barrier fails.
Before construction of the low-permeability soil barrier subcomponent
of the cover system, soil materials should be tested to ensure that they
are as specified in the design. Throughout the construction process, testing
of incoming soil materials should be done on a per-unit-volume basis, and
more frequently when the inspector suspects a change in soil properties.
The low-permeability soil barrier is constructed very much like the
low-permeability soil liner. Before installation of the soil barrier, a
test fill should be constructed with the same materials, equipment, and
procedures to be used for constructing the soil barrier to ensure that the
required permeabilities can actually be achieved in the field and to deter-
mine the relationship between soil density/moisture content/compactive
effort/permeability achieved in the test fill (see Section 2.3.4.1.2).
This same relationship then must be obtained during the construction of the
low-permeability soil barrier subcomponent. As with compacted low-permea-
bility soil liners, it is necessary to monitor soil type, moisture content,
density, compactive effort, lift thickness, clod size, uniformity of compac-
tion, completeness of coverage, and permeability. A more complete discussion
of inspection activities for low-permeability soil liners can be found in
Section 2.3.4.
Seals around penetrations such as gas vent pipes and LCS standpipes
should be tested to ensure that they do not leak. Compaction of the soil
around penetrations should be closely observed and clod size, especially
where soil is compacted using hand compactors, must be carefully controlled.
It is especially important to inspect the perimeter of the cover, where the
low-permeability soil barrier subcomponent joins or overlies the liner
system, to ensure that it is installed to conform to the specified design.
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After completion of the low-permeability soil barrier subcomponent,
the surface slope of the barrier layer should be surveyed to ensure that it
is constructed as designed and that no depressions remain into which water
will flow and stand. In addition, the soil layer should be inspected to
ensure that it provides a suitable base for the overlying flexible membrane
barrier.
2.3.7.2.3 Flexible membrane barrier instal1ation--The flexible membrane
barrier prevents infiltration of precipitation through the cover and into
the underlying waste.
Before installation of the flexible membrane barrier, the membrane
materials should be observed and tested to ensure that they are as specified
(see Section 2.3.5.1). Field seaming equipment and materials should be
examined to ensure that they are as specified in the design and are adequate
to do the job. Any other materials, such as hardware for anchoring and
sealing the membrane to penetrating objects, should be checked for adherence
to design specifications.
The base for the flexible membrane barrier subcomponent (the low-
permeability soil barrier subcomponent) should be inspected before membrane
installation to ensure that its surface is as smooth as possible and that
there are no objects that might damage or penetrate the membrane.
All observations and tests used for FML installation are pertinent to
the installation of the flexible membrane barrier final cover system sub-
component. A discussion of inspection activities for flexible membrane
liners is presented in Section 2.3.5. CQA personnel should be especially
attentive to the vent and standpipe penetrations to ensure the integrity of
the connections bonding them to the membrane. Around the perimeter of the
final cover system, where it joins the liner system, the installed flexible
membrane barrier should be tested to ensure that it is installed to conform
to the specified design since this is an area with a relatively high poten-
tial for leakage.
2.3.7.2.4 Bedding layer placement—An upper bedding layer may be
placed to act as a protective buffer between the flexible membrane barrier
subcomponent and the overlying drainage layer. This layer acts to protect
the membrane from possible puncture by coarse drainage system materials.
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Bedding layers may be either a granular material or a synthetic material
such as a geotextile. Specific observations and tests to be performed are
listed in Section 2.3.5.2.4.
Perhaps the most critical inspection activity during the placement of
a bedding layer on top of a flexible membrane is to observe the placement
process closely to ensure that the construction equipment does not damage
the membrane. Following installation, the surface slope of the bedding
layer should be surveyed to ensure that the design slope is achieved.
2.3.7.2.5 Drainage and gas venting layer placement—The drainage
layers in a final cover system are designed to conduct away infiltrating
precipitation before it can penetrate the barrier layers and to vent gas
from the facility to appropriate treatment or collection facilities. The
gas discharge layer has a consistency and configuration similar to that of
the water drainage layer. Both layer types function to transmit fluid
preferentially. The main distinction between them is their position in the
cover system. The gas discharge layer is placed below the flexible membrane
and low-permeability soil barriers and intercepts gases rising from waste
cells and directs them to controlled gas discharge vents. The water drainage
layer is located above the barriers to intercept and drain water percolating
from the surface and direct it to the runoff control system. Both the gas
venting and water drainage layers in a final cover system are similar in
design and construction to the leachate collection system and may be composed
of granular soils and/or geotextiles. See Section 2.3.6.2.3 for a more
detailed description of drainage layers.
Current regulations require controlled discharge (collection and/or
treatment) of hazardous or nuisance gases from facilities. Controlled
discharge of gases accumulating in the facility is necessary because of the
potential harm that toxic and/or malodorous gas may have on human health
and the environment. The gas may be collected at the discharge point and
transported for treatment or incineration. Alternatively, devices for
removing harmful components from the gas or incinerating the harmful com-
ponents in place may be devised and installed at gas discharge points.
This document does not cover these devices in further detail, as currently
there is no guidance for designing or constructing them.
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The materials used in the construction of the drainage or venting
layer are likely to have restrictive specifications, whether materials are
soil or synthetic materials. Preconstruction activities must include an
inspection of those materials to make certain that they meet the design
specifications. The inspection should continue through the construction
period as long as materials continue to be delivered to the site. Other
preconstruction activities include inspection of the base for the drainage
or gas venting layer to ensure that it is and remains in the condition that
was specified in the design. Any protrusions, such as vents and standpipes,
should also be inspected for any deviations from design specifications.
The inspection procedures during the construction of the drainage and
gas venting layers are much the same as those used in the construction of
the leachate collection system at the bottom of the landfill. Those proce-
dures are addressed in detail in Section 2.3.6.2. Inspection activities
will include ensuring that the specified thickness and surface slope are
achieved and that grain size and hydraulic (or gas) conductivity are as
specified in the design. Observations should be made of the filling process
around vents and standpipes to prevent damage or misalignment of those
structures.
Inspection of the installation of the drainage layers around the
perimeter of the cover system is particularly important, for it is here
that the system connects to the surface drainage facilities. It is espe-
cially important to ensure that the design specifications, particularly
dimensions and slopes, are achieved. In addition, controlled gas discharge
or collection systems should be checked for proper installation and function.
2.3.7.2.6 Filter layer placement—The purpose of a filter layer above
(or below) a drainage layer is to stop the migration or piping of fine
materials that could plug a drainage layer and render it ineffective. The
filter layer can be constructed of soil materials or may be a geotextile.
Soil layer specifications include grain size range and dry density. Geotex-
tiles are specified according to granular equivalency.
Inspection activities prior to the construction or installation of the
filter layer include inspection of the filter materials to confirm that
they meet the design specifications.
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During the construction of the filter layer, inspection activities
will include monitoring of the grain size (for soil materials) or geotextile
type and certification, uniformity of thickness for soil, seaming or overlap
for geotextiles, slope of the surface, and coverage (particularly around
the perimeter of the cover system). The inspector should be particularly
aware of the potential for damage to penetrating objects such as vent pipes
during the construction process. The perimeter area, where the drainage
layer intersects surface drainage, should be closely inspected for adherence
to the design specifications. More information on CQA inspection activities
for filter layer placement is found in Section 2.3.6.2.4.
2.Z.I.2.1 Topsoil layer placement—The topsoil layer is the uppermost
component of the cover system. Its functions are to protect the underlying
layers from mechanical and frost damage, and (in conjunction with a vegeta-
tive cover) to protect against erosion.
Topsoil specifications are likely to include properties (e.g., nutrient
and organic content) not required for the other soil components of the
facility. Soil specifications typical of the other earthwork components
may also be included, however.
Reconstruction inspection activities will include checking topsoil
properties against the design specifications and ensuring that deleterious
materials are not included. The foundation for the topsoil layer will be
the filter layer above the drainage layer. The filter layer should be
checked to ensure that it has been constructed to meet or exceed the speci-
fied design and that any specified penetrations are intact and properly
oriented.
During construction of the topsoil layer, the inspector should monitor
the uniformity of the application process, observe the placement procedure
to ensure that the soil is not overly compacted, and measure the thickness
and slope of the topsoil layer. The inspector should also ensure that care
is taken in the vicinity of vents or other protrusions to prevent damage by
construction equipment.
2.3.7.2.8 Topsoil seeding--Topsoi1 placement, preparation for seeding,
and the seeding may take place in a more or less continuous operation.
Inspection before the seeding process should include confirmation that the
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soil additives and seed are as specified in the design. Tilling depth
should be measured, and the application rate of additives should be monitored
to confirm that it is as specified in the design. The slope of the final
surface of the cover should also be verified to ensure that it meets the
design requirement. The inspector should verify that all vents and stand-
pipes or any other penetrations through the cover are not damaged by the
tilling and additive application processes.
The seeding method is also likely to be specified in the design, and
the inspector should ensure that the application equipment is appropriate
for the job; e.g., if hydromulching is called for, then hydromulching
equipment should be available and used. The rate of seed and mulch appli-
cation, amount and uniformity of coverage, and watering instructions should
be followed carefully. Perimeter areas should be examined to ensure that
bare spots are not left inadvertently. If tacked mulch is used, the opera-
tion should be observed to ensure that it is as specified.
Timing of seeding is important, particularly for grasses. The inspector
should ensure that it occurs during the designated period and that the
weather is favorable. For example, seeding should not take place during
high wind or rain or when the soil is frozen. Description of the inspection
activities that should be conducted during final cover system seeding may
be found in Gil ham et al. (1983).
2.3.7.3 Postconstruction--
The inspector should make a visual check of the completed cover to
ensure that it meets the specified design. Slopes should be surveyed, any
unusual depressions should be noted and corrected, and the vents and stand-
pipes should be examined for alignment and orientation. The perimeter
configuration, including drainage conduits also should be examined for
conformance to design specifications.
Inspection of the cover should continue until it is ascertained that a
vegetation cover has, in fact, been reasonably well established. Grass and
ground cover should be evaluated once a month by a qualified specialist
during the first 4 to 6 months following germination (Gilman et al., 1983).
At that time a final check should be made of the final cover to ensure that
it is as specified.
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2.4 SAMPLING REQUIREMENTS
The fourth element of a CQA plan describes the sampling requirements
for evaluating construction quality. Sampling requirements for construc-
tion materials and processes for the various components of a hazardous
waste land disposal facility should include the following:
Size of the Unit (or Block) to be Sampled. A unit or block
is a definite isolated quantity of material or construction
work, constant in composition and produced by a uniform
process, that is presented for inspection and acceptance as
a unit (Section 2.4.1).
Number of Sample Items or Measurements per Inspection Block.
The number may be established by the designer or CQA officer
on the basis of judgment or by statistical methods (Sections
2.4.3.1 and 2.4.3.2).
Location(s) of Sample Items or Measurements. Locations for
individual observations or for sampling may be established
by the designer or CQA officer on the basis of judgment or
statistical methods (Sections 2.4.2.1 and 2.4.2.2).
Acceptance Criteria. The determination of natural process
variabilities, levels of confidence, and acceptance criteria
for each characteristic are all design functions, involving
site-specific requirements and engineering experience,
skill, and judgment. Acceptance criteria should reflect the
type of sampling plan (judgment or statistical) that is
employed (Section 2.4.2). The design specifications, accept-
ance/rejection criteria, and sampling methods must be con-
sistent and closely coordinated by the design engineer in
the design report and CQA plan.
Treatment of Outliers. Criteria for identifying and rejecting
outlying test results may be established based on confidence
level requirements (statistical sampling methods only) or
based on the judgment of the CQA officer (Section 2.4.4).
Corrective Measures to be Taken in the Event of Noncompliance.
When a quantity of work or material is rejected, it must be
reworked to bring it up to specification or replaced by
acceptable work (Section 2.4.5). The actual physical means
of correction in the case of noncompliance is a combined
design and construction operations function; this topic is
beyond the scope of a CQA document.
For many materials or construction processes, it is necessary to
estimate the quality of the overall material or process from the observed
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or measured quality of a representative sample that is a small fraction of
the total material or process. Examples of these situations include assess-
ment of characteristics of a soil liner (permeability, moisture content,
density, grain size), testing chemical compatibility of an FML, and destruc-
tive testing of FML seams. This section provides general guidance for
selection and implementation of an appropriate sampling scheme and specifies
what constitutes a sample item, how the items will be selected, and the
number of items to be selected.
2.4.1 Definitions of Sampling Terms
The term block, as used herein, refers to a definite, isolated quantity
of material, such as soil, of constant composition and produced by essential-
ly the same process, that is presented for inspection and acceptance.
Alternatively, it may be a unit of construction work that is assumed to
have been produced by a uniform process. It is characteristic of a block
that all variation among measured properties within it is random, or is
assumed to be random, with no underlying differences between locations in
the block. Therefore, the block can be characterized by a block mean and a
block variance for each quality characteristic.
Block size is established on the basis of judgment of uniformity of
materials and/or workmanship and on economics of inspection. Generally,
materials and/or workmanship close together in time or space will be more
similar than elements far apart. A block may be any unit presented for
quality evaluation and acceptance. This may be a single day's production,
a portion of a day's work, a stockpile of material from a uniform, well-
defined source, or a single shipment of offsite material.
For sampling purposes, a block is usually subdivided into a number of
batches of sample units, each a small and easily identified length, area,
volume, weight, package, or time period. A batch is a discrete unit or
subdivision of a block of material, such as a package or roll of geomembrane,
a truck load of sand or portland cement, or a length of drain tile. A
sample unit is an arbitrary subdivision, in time or space, of a block of
material or workmanship. A lift of compacted fill, a length of membrane
seam, or an exposed face of trench wall may be subdivided in some rational
fashion.
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A sample item is that portion of material removed (or tested in place)
from each selected batch or sample unit. A sample is a collection of
sample items, such as test bores, truck loads, grid sections, or sections
of an FML seam. Each item in the sample is independent from the other
items in the sample and data are collected for each sample item. The
sample may represent a block of construction material, a block of construc-
tion processing, or an incoming shipment of offsite material for the purpose
of inspection as a basis for judging, or estimating, the quality of the
block.
2.4.2 Sampling Strategies
The establishment of sampling methods and of sampling and testing
frequency may be based on either judgment or experience or on probabilistic
methods using statistical theory (Deming, 1950). Willenbrock (1976) states
that, up until the last 10 to 15 years ". . . quality of construction was
largely accomplished through semi-artisan techniques and procedures with
constant visual inspection," or in other words, judgment sampling. Judgment
methods were, and still are, subject to biases and sampling errors (Deming,
1950) dependent on the knowledge, capability, and experience of the specifi-
cation writers, the inspection staff, and the CQA officer. These factors
cannot be easily evaluated and documented. Methods using statistical
theory are more rational, calculable, and documentable than judgmental
methods and are recommended where feasible and applicable. Whether judg-
mental or statistical sampling is to be used, it is imperative that the
procedure to be used is clearly and completely specified in the CQA plan
and is an accepted approach to sampling the construction materials or
operations being evaluated. The rationale used to select and develop the
sampling approach should be explained in the CQA plan.
2.4.2.1 100-Percent Sampling--
The ideal situation is that where the quality of al1 of the material
used for a particular component of a hazardous waste land disposal facility
an be assessed by an objective observation or test procedure. Clearly
these procedures are limited to observations and nondestructive tests that
are relatively inexpensive in terms of resource and time requirements.
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Examples of such methods are those tests used for FML seams and anchors,
collection system pipe joints, pump function, electrical connections, and
final leak detection (filling a facility with water). A less than optimum,
but necessary, situation is where the quality of a material is assessed by
subjective evaluation (usually visual inspection) of all of the material.
2.4.2.2 Judgment Sampling--
Judgment sampling refers to any sampling program where decisions
concerning sample size, selection scheme, and/or locations are based on
other than probabilistic considerations. The objective may be to select
typical sample elements to represent a whole process or to identify zones
of suspected poor quality. Sampling frequency is often specified by the
designer and may be a function of the confidence he has in the CQA personnel.
Selection of the sampling location(s) is often left up to the inspector or
CQA officer making the entire process dependent on the validity of his
judgment.
There can be no standardized rules for judgment sampling simply because
such sampling depends on the judgment of the designer, CQA official, and/or
inspection staff. Because judgment sampling plans are based on the experi-
ence and opinions of the CQA personnel, sample estimates (e.g., mean,
variance, or relationship among variables) may be biased and hence may not
accurately represent the overall material or process. There is no way to
test for or to quantify these inherent biases nor to estimate the level of
confidence associated with the sample estimates. For example, with a
judgment sampling scheme, it is not possible to estimate how closely the
quality measurement of the sample approximates that of the overall material
or process with a specified level of confidence.
2.4.2.3 Statistical Sampling--
There is an inherent, or natural, variability in measurement data for
any specified quality characteristic of most materials and components used
in construction (Terzaghi and Peck, 1967), including the materials and
processes used to construct a hazardous waste land disposal facility. This
variability may be attributed to variability in material quality, construc-
tion operations, measurement techniques and instrumentation, as well as the
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overall capabilities of the inspection staff. There is a need for formalized
statistical sampling methods to estimate or describe the overall quality of
the individual facility components and for an assessment of the variability
in test results that might occur if multiple independent samples were
collected.
Statistical sampling methods are based on the principles of probability
theory and are used to estimate selected characteristics (e.g., mean,
variance, percent defective, relationships) of the overall material or
process (population). The primary differences between these methods and
those based on judgment are that sample selection is by an objective process
that reduces the likelihood of selection bias (i.e., every sampling unit
has a known likelihood of selection) and provides a means of assessing the
magnitude of potential error in the sample estimate(s) (i.e., variability
in sample estimates that would be observed if multiple independent samples
were selected or the likelihood that the sample estimate does not deviate
from the overall characteristic to be estimated by more than some specified
amount).
In statistical sampling, a sample unit refers to entities that are
enumerated for purposes of sample selection and may or may not be the items
that are measured. For example, if a grid is overlaid on a soil liner and
grid sections are selected into the sample, the grid sections are the
sample units; a single measurement, such as size, might be performed for
each grid section or a sample of smaller units (e.g., core sections) might
be selected from each grid section for testing. The underlying requirement
for a statistical (or random) sample is that all of the units selected into
the sample must have a known probability (chance) of selection into the
sample. An example of a common approach is to assign a unique serial
number to each potential sampling unit in the overall material or process
and select serial numbers by some random process such as drawing numbers
from a hat or using a random number table.
There are many variations in random sampling plans that can be used.
Some examples are:
If the soil to be used to line a hazardous waste land disposal
facility is known to be different in one area of the borrow
source from another, independent samples might be selected
from each area and the results combined by a weighting
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scheme depending on some property of the differentiating
characteristic such as grain size, consistency, or overall
density (stratified sampling).
If it is impractical to enumerate all possible sample items
(or points), it may be possible to select a small number of
large sample units and then select a sample of measurable
elements from each unit. The previously mentioned example
of selecting core sections from a sample of grid sections of
a soil liner illustrates this type of sampling (two-stage
sampling plan).
If many loads of soil are being hauled to a site and it is
reasonable to assume that the loads are homogeneous relative
to a particular characteristic, it may be desirable to
examine every nth load after starting with a randomly selec-
ted start less than 'n' (systematic sampling).
If the goal is to assess some characteristic of a compacted
soil lift, it may be desirable to overlay the site with a
grid pattern and to select grid sections for sampling by
randomly selecting coordinates. In this situation, if each
section has an equal chance of selection, the plan would be
classified as simple random sampling. If instead the plan
specified that the selection probabilities be in proportion
to some known characteristic such as area of grid section,
it would be classified as a proportionate sampling. For
example, if some grid sections are twice as large as others,
the large sections could be given twice the probability of
selection as the small sections. The primary caution is
that selection probabilities be known in advance or be equal
for all units in an area and that an accepted statistical
technique be used for selection of random numbers. It is
not satisfactory to use some other means of selecting sample
units such as picking numbers from the air.
The plan used for each evaluation should be tailored to the particular
situation and types of sample estimates desired. If the goal is to estimate
some characteristic of a completed component or process, a simple random
sample design or some modification such as a stratified or two stage sam-
pling plan should be used. If the goal is to monitor an ongoing operation
such as placement of soils by trucks, a systematic sampling plan may be
used, where every nth truck would be examined after a random start. The
reason for this selection is that the latter design does not require complete
ennumeration of the potential sampling units whereas some such enumeration
scheme is usually necessary for the other designs. Once the data have been
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collected from a particular sampling plan they must be summarized, analyzed,
and presented in a way that is tailored to the sample design that was used.
Since all of the sampling designs are based on the principles of
simple random sampling, the remaining discussion will be limited to these
designs. For more information concerning the available sampling designs or
their underlying probability and distributional properties and assumptions,
see Kish (1967).
2.4.3 Selection of Sample Size
The sample size is the number of sample items whose test outcomes are
combined mathematically to yield sample parameters. Sample size may be
selected by judgment or statistical methods. The judgment method is subjec-
tive, based solely on intuition. Classical statistical methods are based
on sample-derived statistics and on judgment-selected confidence levels.
2.4.3.1 Judgment Method--
The judgment method depends almost entirely on the intuition of the
specifier, presumably based on engineering and materials evaluation experi-
ence. All of the comments made earlier, in Section 2.4.2, regarding sampling
methods also apply to sample size selection. Judgment methods result in
sample means, sample variances, and variable relationships that may be
biased and, therefore, may not accurately represent the overall material or
processes. These biases cannot be quantified; thus the level of confidence
associated with sample estimates cannot be estimated for judgment sampling
schemes.
Testing frequency for judgment sampling schemes is often set to produce
a fixed proportion of the population (such as 10 percent) or to yield a
prespecified sample size per specified unit of time, distance, area, or
volume (e.g., taking samples of FML seams on a per linear foot basis). The
sample proportions or sizes are usually established on the basis of judgment
and experience from similar construction projects. Sampling schemes are
usually used to specify minimum sampling frequencies. These frequencies
can be increased to identify potential problem areas where additional tests
should be made. Samples ideally should be located where the inspector has
reason to doubt the quality of materials or workmanship.
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Organizations that construct large numbers of similar projects, such
as the U.S. Army Corps of Engineers or the U.S. Bureau of Reclamation,
often employ judgment sampling with sampling frequencies based on knowledge
from their years of construction experience. Usually a range of sampling
frequencies is suggested, with estimates of site- and material-specific
variability determining which end of the range to use initially. Table 2-1
lists test frequencies used by various organizations for earthwork construc-
tion.
Other examples of sampling plans can be found in standard specifications
such as AASHTO (1983) and ASTM (1985b), particularly for sampling and
testing of materials. The sampling of a batch, such as a soil stockpile,
in which some segregation may have naturally occurred, often involves
taking three or more sample items that are blended into a single represen-
tative element for analysis.
2.4.3.2 Statistical Methods--
A statistically rational and valid method for selecting sample size is
given in ASTM (1985b) E 122-72. The equation for the number of sample
units (sample size, n) to include in a sample in order to estimate, with a
prescribed precision, the average of some characteristic of a block is:
n - (ts/E)2 (2.1)
or, in terms of coefficient of variation
n = (tV/e)2 (2.2)
where
n = number of units in the sample
t = probability factor
s = the known or estimated true value of the standard deviation for
the overall material or process to be estimated
E = the maximum allowable error between the estimate to be made from
the sample and the result of measuring (by the same methods) all
of the units in the overall material or process
e = E/X, the allowable sampling error expressed as a percent (or
fraction) of X
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TABLE 2-1. MOISTURE/DENSITY TEST FREQUENCY RECOMMENDATIONS
FOR EARTHWORK QUALITY CONTROL
USBRa U.S. Navyb U.S. Armyc
Mass earthworks 1 per 2,000 yd3 1 per 500 yd3 1 per 1,000 to
(embankments, dikes) 3,000 yd3
Earth linings 1 per 1,000 yd3 1 per 500 to
1,000 yd3
Hand-tamped backfill 1 per 200 yd3 1 per 100 to
200 yd3
Minimum per shift 11--
(mass earthwork)
Doubtful areas 11--
(inspector's discretion)
Pervious materials 1 per 1,000 to
10,000 yd3
aUSBR (1974).
bU.S. Department of the Navy (1982).
CU.S. Department of the Army (1977).
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X = the expected (mean) value of the characteristic being measured
V = coefficient of variation.
The probability factor, t, in equations (2.1) and (2.2) is the standard
normal deviate (see ASTM, 1985b, for description) that corresponds to the
chosen level of confidence that the sample estimate will not differ from
the true value of the "to be estimated" characteristic for the overall
material or process by more than the allowable error (E). For a two-sided
test (test for error both above and below the estimated value), the commonly
used values of t are 1.96 or 1.64, corresponding to 95 and 90 percent
levels of confidence, respectively. For a one-sided test (test for error
in one direction only), a value of 1.64 corresponding to the 95 percent
level is commonly used. For values of t (or z, as indicated in many tables
and texts) corresponding to other levels of confidence, see any basic
statistics book.
As described in ASTM (1985b) E 122-72, the estimated standard deviation,
s, should be derived from previous measurements of standard deviation for
the same material or process, and should have been developed from at least
30 measurements. As new data are collected from subunits of the overall
material or process, they can be used to supplement or replace the old data
(depending on comparability of the new and old data) to further refine the
estimate of s and the resulting sample size estimate. If no previous data
exist, s can be roughly approximated from background knowledge of the shape
of the distribution or by conducting a pilot, or preliminary, study where a
small number of measurements are performed on a subset of the overall
material or process (possibly on the test fills).
It should be recognized that a sample size determination is an esti-
mate (or best guess) of the minimum quantity sufficient to satisfy stated
objectives. Since the estimates are based on historical data or subjective
opinions of the underlying distribution and cannot take into account all of
the factors that contribute to sample variability, they may not be adequate
to produce assessments with the prespecified level of confidence. It is
always necessary to recompute confidence levels as part of the ordinary
data analysis of the sample data. If the resultant confidence level is not
sufficient, it may be necessary or at least desirable to supplement the
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sample to attain the desired level. As long as the original sample was
selected by an accepted random process, the test methods have not changed
since the initial sample analysis, and the same sampling scheme used for
the original sample is used for the supplement (i.e., every sample unit has
an equal likelihood of inclusion in either the original or supplemental
samples), it usually will be satisfactory to combine the two samples to
reduce variability of the sample estimates and hence increase the confidence
level. It is not acceptable to use sample supplementation in an attempt to
change sample estimates (such as means) to make them more acceptable.
A sample size designed to produce estimates with prespecified reliabil-
ity or confidence for the overall material or process probably will not be
adequate to assess the quality of some subsection where there is a need for
separate evaluation. For example, the sample size selected for determining
whether the overall clay liner meets the maximum criteria for permeability
probably will not be sufficient to assess the permeability of a particular
section of the liner where the soil appears to differ from that used in the
rest of liner. Therefore it may be necessary to increase the sample fre-
quency or sample size for a subarea where visual observations of materials
or construction operations indicate that the quality of construction is
suspect. If these data are to be combined with the rest of the data from
the overall site, all data analyses must include an adjustment for the
differences in sample selection probabilities between the two samples.
2.4.3.2.1 Acceptance sampling—For some characteristics, such as
flexible membrane liner strength or soil permeability, a limit of accepta-
bility (e.g., permeability less than 10 cm/s) can be specified. If the
standard deviation of the characteristic can be estimated, then the overall
mean that must be achieved to ensure (with a prespecified confidence level)
that a predetermined number of samples violate the limit can be specified.
-ft
For example, if the standard deviation in soil permeability is 10 cm/s
and it would be undesirable to have more than 2 percent of the samples with
permeability measurements greater than 10 cm/s, then the acceptable mean
level would be 10"7 - 2.05 (10~8) = 7.95 x lo"8 cm/s. If, however, it is
deemed satisfactory for 0.2 percent of the permeabilities to exceed the
_ ~7
specification of 10 cm/s, then the acceptable mean level would be
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10 - 2.88 (10~8) = 7.12 x 10 cm/s. Using these means along with consid-
erations of the acceptability of judging an unacceptable material or process
as acceptable or rejecting an acceptable material as unacceptable (type II
and I errors, respectively, in statistical terminology), a required sample
size can be estimated (Burr, 1976).
2.4.3.2.2 Sequential sampling plan—All of the sampling plans and
sample size estimates discussed so far (with the possible exception of
sample supplementation to reduce variance of sample estimates) assume that
the sample size or sampling frequency will be determined prior to initiation
of the sampling program (i.e., the data from the sample will not influence
these estimates). The purpose of sequential sampling plans is to obtain
sufficient data for evaluation of quality with fewer sampling units on the
average than that required by even the best single sample plans. The
general approach is to determine after selection and testing of each sample
unit if an evaluation can be performed with acceptable precision. If so,
the sampling process is terminated; if not, another sample unit is selected.
Hence, if the test results are very uniform and at the levels originally
hypothesized (or desired) or if the results deviate markedly from the
hypothesized (or desired) levels, a decision to accept or reject the material
or process can be made with few sample units. If, however, the data are
highly variable and reasonably close to the rejection criteria, a larger
sample will be required before a decision can be made. Hence the sample
size is a variable in this type of sampling design.
2.4.4 Treatment of Outliers
Occasionally, in a supposedly homogeneous sample, one of the test
values appears to deviate markedly from the remainder of the sample. Such
a value is called an outlier. Rules for rejection of outliers are based on
confidence level criteria. Standard practice for dealing with outlying
observations are contained in ASTM (1985b) E 178. This practice may be
applied only to random, statistically evaluated samples. According to
ASTM E178, two alternative explanations for outliers are of interest:
An outlying observation may be an extreme manifestation of
the random variability inherent in the data. In this case,
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the value should be retained and processed with the other
observations in the sample.
An outlying observation may result from gross deviation from
the test procedure or an error in calculating or recording
the numerical value. In this case, the outlier may be
rejected or not, if used in the subsequent analyses, the
outlying values will be recognized as being from a different
population than the other sample values.
ASTM E178 provides statistical rules that lead the investigator to look for
causes of outliers and decide which of the above alternatives apply so that
the most appropriate action may be taken in further data analysis. The
procedures used are too extensive to quote in this document, and the reader
is referred to ASTM (1985b).
2.4.5 Corrective Measures Implementation
In the event of noncompliance, when material or work is rejected
because observations or tests indicate that it does not meet the design
criteria, plans, and specifications, corrective measures must be implemented.
For material subject to 100-percent inspection, substandard material is
simply rejected. When workmanship subject to 100-percent testing is rejected
(e.g., synthetic membrane seams), it must be redone until it meets specifi-
cations. For workmanship in question because of an inspector's observations,
additional testing of the component may be necessary prior to rejecting the
block of work and specifying corrective measures.
In general, the rejection of any material or workmanship on the basis
of test results may be a result of deficiencies in the work or material or
errors in the test results. If the probability of systematic error in the
test methods and the actual variability of the measured parameters are
known and statistical sampling methods are used, then a degree of confidence
in the test results, based on the number of tests per block of work or
material, can be estimated. However, this does not consider the possibility
of random error that may be introduced by such factors as poorly conducted
tests or mistakes in recording test results. Because the cost of additional
testing is considerably less than implementing most corrective measures, if
a block of work is rejected on the basis of a failed test or series of
tests, implementing the following sequence of corrective measures may be
prudent (adapted from Selig, 1982):
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Rerun the field test(s). If the second test passes, an
error in the first test may be assumed and the work or
material may be accepted.
If the second test fails, require the contractor to attempt
to rework the material in place to bring it up to specifica-
tions, and retest.
If the work still fails, remove the material and replace it,
testing the new material to ensure compliance.
For any facility component, the actual physical means of corrective
measures, in the case of noncompliance, is a combined design and construc-
tion function. Both of the latter topics are beyond the scope of this
document.
2.4.6 Control Charts
For some materials or processes it may be necessary or desirable to
maintain records of quality over time. For example, it may be necessary to
assess the grain size of truck loads of incoming soils used in preparing
the liner. Assuming that the loads are relatively homogeneous (there are
no major differences in soil types or moisture content among the loads) a
control chart approach might be used. A systematic sampling design could
be used to select incoming truck loads for analysis and the test results
would be plotted against time. These types of plots provide a means to
keep track of the incoming materials so that appropriate action may be
taken whenever it is indicated (actions to be taken in response to devia-
tions from the norm should be specified by the design engineer). For some
material or properties, deviations in quality in either direction may be
important (such as soil moisture content); for others, deviations in only
one direction will be of concern (such as soil permeability).
One of the fundamental questions of this approach is: What is an
abnormal test result? Upper and lower limits of acceptability about the
norm or mean of the test results can be established by assuming that the
measurements are normally distributed and setting limits that will include
a predetermined proportion of the measurements (usually 90 or 95 percent)
or by setting them at some predetermined level of acceptability (such as a
maximum of 10 level of permeability for soils used as liner material).
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For those measurements where little is known concerning natural variability
and there is no sound basis for setting a level of acceptability, the test
results from experimental sites (e.g., test fills) could be used to estab-
lish a norm and usual variation that could be used for setting up the
control chart.
It will likely be advisable to revise the control chart limits as
tests are performed on the disposal site; these changes should only be done
with the concurrence of the CQA officer and the design engineer. All
measurements that fall outside the established limits should be referred to
the CQA officer, who will attempt to identify the cause for deviation and
the appropriate action to rectify the problem; specific responses to devia-
tion should be specified by the design engineer. The usual practice in
guality control statistics is to record summary results (means, standard
deviations, or ranges) of multiple measurements for each sample, where each
sample consists of a series of subunits; an example of this approach might
be used in a design where large soil samples are selected from a liner by a
grid system and multiple measurements of soil density are performed for
each grid section. For land disposal sites, however, it will probably be
more common to record individual measurements on the control chart (Burr,
1976). The sample size/frequency (number of sample unit or sampling inter-
val), sampling unit (truck load, grid section of liner, etc.), and acceptance
criteria must be determined by the design engineer and will depend on the
specific goal of an assessment, the site-specific characteristics of a
particular material or process to be evaluated, and the expected vari-
ability of the test data.
Control charts can be used to monitor the guality of material or
workmanship over time, providing a useful record of the performance of a
construction contractor or material variability as the facility is being
constructed. For example, the owner/operator, design engineer, or CQA
officer may use these charts to detect trends in workmanship guality that
may not be apparent when comparing the results of individual tests. With
the use of control charts, declines in workmanship guality can be correlated
with potential causes (e.g., weather conditions) and appropriate corrective
measures (e.g., changes in operating procedures, additional training pro-
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grams, or more frequent testing) may be implemented in a timely fashion.
Another example would be using control charts to detect increases in material
variability that may require more frequent testing of the incoming material.
Properly maintained control charts can provide an immediate review of
the quality of a block of material or workmanship (Beaton, 1968). They
provide a convenient and concise means of documenting construction quality
and may serve to summarize a great volume of test reports and other records,
speeding up review of test records and acceptance of a block of completed
work.
An example of a control chart is presented in Figure 2-3. In the
upper graph, individual test results for a block of material are plotted in
chronological order. In the lower graph, a moving average of the test
results is plotted on a graph. If the average test results are in the
shaded area (approaching the rejection level), more frequent testing is
required to accept the lot. Below the shaded area, the lot is accepted;
above it, it is rejected. If statistical sampling methods are used, the
acceptance/rejection levels and the levels requiring more testing may be
determined by statistical methods, as described earlier in this section.
Kotzias and Stamatopoulos (1975) used three types of control charts
with judgment sampling methods to evaluate construction quality for an
earthen dam. Simple quality control charts were used to evaluate day-to-day
construction performance. These charts plotted daily averages and ranges
of test results over the course of the construction period and are valuable
chronological records, but are not formal control charts. Rejection charts
(Figure 2-4) plot the total number of rejected tests cumulatively and the
magnitude of each rejected result against the total number of test results
(retests excluded). These charts reveal the rejection rate and the severity
of defects in the rejected material (compacted earthfill). Finally, fre-
quency diagrams (Figure 2-5) were plotted for whole components or for
sampling blocks. These diagrams were presented in pairs, i.e., defects
included, retests excluded (before remedial action), and defects excluded,
retests included (as accepted). These charts are bar diagrams plotting
number of test results against test results (Figure 2-5). Evaluated jointly
with rejection charts (Figure 2-4), they provide a way of determining the
overall importance of defects and remedial measures.
80
-------
Individual Test
Reject
Test More Frequently
11
(Beaton, 1968)
12 13 14 15 16
Moving Average
17
18
Figure 2-3. Control charts, individual and moving average.
01
-------
Total Number of Test Results (Retests Excluded)
30 40 50 60 70 80 90
Total number of test results 119
Total number of rejects 30
Average rejection rate 340/o
Percent of total volume of dam
30% E.T.C. = percent rejection
(Beaton, 1968)
Figure 2-4. Rejection chart: density measurements for dam core compaction control.
82
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REJECTED
ACCEPTED
As accepted
X = 100.55
a = 2.00
N =99
Before remedial action
X = 98.50
a =3.76
N = 115
As accepted
Before remedial action
92 94 96 98 100 102 104
% Compaction
From Kotzias and Stamatopoulos, 1975
Figure 2-5. Frequency diagram: density measurements for dam core compaction control.
83
-------
Although control charts may be used with either judgment or statistical
sampling, when used with judgment methods they reflect the bias inherent in
the judgment sampling. Thus, the "as accepted" frequency diagrams may not
accurately represent the quality of the completed work for judgment sampling,
but will for a sampling plan determined by statistical methods.
For more information concerning the use of control charts see standard
texts concerning quality control such as Duncan (1959), Burr (1976), or
Grant (1964).
2.5 DOCUMENTATION
The ultimate value of a CQA plan depends to a large extent on recogni-
tion of all of the construction activities that should be inspected and the
assignments of responsibilities to CQA personnel for the inspection of each
activity. This is most effectively accomplished by documenting CQA activi-
ties and should be addressed as the fifth element of the CQA plan. The CQA
personnel will be reminded of the items to be inspected, and will note,
through required descriptive remarks, data sheets, and checklists signed by
them, that the inspection activities have been accomplished.
2.5.1 Daily Recordkeeping
Standard daily reporting procedures should include preparation of a
summary report with supporting inspection data sheets and, when appropriate,
problem identification and corrective measures reports.
2.5.1.1 Daily Summary Report--
A summary report should be prepared daily by the CQA officer. This
report provides the chronologic framework for identifying and recording all
other reports. At a minimum, the summary reports should include the follow-
ing information (Spigolon and Kelley, 1984):
Unique identifying sheet number for cross-referencing and
document control
Date, project name, location, and other identification
Data on weather conditions
Reports on any meetings held and their results
84
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Unit processes, and locations, of construction underway
during the time frame of the daily summary report
Equipment and personnel being worked in each unit process,
including subcontractors
Descriptions of areas or units of work (blocks) being inspected
and documented
Description of offsite materials received, including any
quality verification (vendor certification) documentation
Calibrations, or recalibrations, of test equipment, including
actions taken as a result of recalibration
Decisions made regarding approval of units of material or of
work (blocks), and/or corrective actions to be taken in
instances of substandard quality
Unique identifying sheet numbers of inspection data sheets
and/or problem reporting and corrective measures reports
used to substantiate the decisions described in the preceding
item
Signature of the CQA officer.
Items above may be formulated into site-specific checklists and data
sheets so that details are not overlooked.
2.5.1.2 Inspection Data Sheets--
All observations, and field and/or laboratory tests, should be recorded
on an inspection data sheet. Required data to be addressed for most of the
standardized test methods are included in the pertinent AASHTO (1983) and
ASTM (1985a) Standards. Examples of field and/or laboratory test data
sheets are given in Department of the Army (1970, 1971) manuals and in
Spigolon and Kelley (1984).
Because of their nonspecific nature, no standard format can be given
for data sheets to record observations. Recorded observations may take the
form of notes, charts, sketches, photographs, or any combination of these.
Where possible, a checklist may be useful to ensure that no pertinent
factors of a specific observation are overlooked.
At a minimum, the inspection data sheets should include the following
information (Spigolon and Kelly, 1984):
85
-------
Unique identifying sheet number for cross-referencing and
document control
Description or title of the inspection activity
Location of the inspection activity or location from which
the sample increment was obtained
Type of inspection activity; procedure used (reference to
standard method when appropriate)
Recorded observation or test data, with all necessary calcu-
lations
Results of the inspection activity; comparison with specifica-
tion requirements
Personnel involved in the inspection activity
Signature of the appropriate inspection staff member and
concurrence by the CQA officer.
Items above may be formulated into site-specific checklists and data sheets
so that detail? are not overlooked.
2.5.1.3 Problem Identification and Corrective Measures Reports--
A problem is defined herein as material or workmanship that does not
meet the design criteria, plans, and specifications. Problem Identification
and Corrective Measures Reports should be cross-referenced to specific
inspection data sheets where the problem was identified. At a minimum,
they should include the following information:
Unique identifying sheet number for cross-referencing and
document control
Detailed description of the problem
Location of the problem
Probable cause
How and when the problem was located (reference to inspection
data sheets)
Estimation of how long problem has existed
Suggested corrective measure
86
-------
Documentation of correction (reference to inspection data
sheets)
Final results
Suggested methods to prevent similar problems
Signature of the appropriate inspection staff member and
concurrence by the CQA officer.
In some cases, not all of the above information will be available or obtain-
able. However, when available, such efforts to document problems could
help to avoid similar problems in the future.
The CQA officer should be made aware of any significant recurring non-
conformances. The CQA officer will then determine the cause of the noncon-
formance and recommend appropriate changes to prevent recurrence. When
this type of evaluation is made, the results should be documented by the
inspection staff in a brief report containing the supporting problem identi-
fication and corrective measures reports.
Upon receiving the CQA officer's written concurrence, copies of the
report should be sent to the design engineer and the facility owner/opera-
tor for their comments and acceptance. These reports should not be submitted
to the permitting agency unless they have been specifically requested.
However, a summary of all data sheets along with final testing results and
inspector certification of the facility may be required by the permitting
agency upon completion of construction.
2.5.2 Photographic Reporting Data Sheets
Photographic reporting data sheets also may prove useful. Such data
sheets could be cross-referenced or appended to inspection data sheets
and/or problem identification and corrective measures reports. At a minimum,
photographic reporting data sheets should include the following informa-
tion:
A unique identifying number on data sheets and photographs for
cross-referencing and document control
The date, time, and location where the photograph was taken and
weather conditions
The size, scale, and orientation of the subject matter photographed
87
-------
Location and description of the work
The purpose of the photograph
Signature of the photographer and CQA officer.
These photographs will serve as a pictoral record of work progress,
problems, and corrective measures. They should be kept in a permanent
protective file in the chronological order in which they were taken. The
basic file should contain color prints; negatives should be stored in a
separate file in chronological order.
A video recording of problem areas and/or conditions and of the com-
pleted installation of each soil component also may prove useful.
2.5.3 Block Evaluation Reports
Within each inspection block, there may be several quality character-
istics, or parameters, that are specified to be observed or tested, each by
a different observation or test, with the observations and/or tests recorded
on different data sheets. At the completion of each block, these data
sheets should be organized into a block evaluation report. These block
evaluation reports may then be used to summarize all of the site construc-
tion activities.
Block evaluation reports should be prepared by the CQA officer and, at
a minimum, include the following information (Spigolon and Kelley, 1984):
Unique identifying sheet number for cross-referencing and
document control
Description of block (use project coordinate system to
identify areas, and appropriate identifiers for other units
of materials or work)
Quality characteristic being evaluated; references to design
criteria, plans, and specifications
Sampling requirements for the inspected block and how they
were established
Sample item locations (describe by project coordinates or by
a location sketch on the reverse of the sheet)
Inspections made (define procedure by name or other identifier;
give unique identifying sheet number for inspection data
sheets)
-------
Summary of inspection results (give block average and, if
available, the standard deviation for each quality charac-
teristic)
Define acceptance criteria (compare block inspection data
with design specification requirements; indicate compliance
or noncompliance; in the event of noncompliance , identify
documentation that gives reasons for acceptance outside of
the specified design)
Signature of the CQA officer.
2.5.4 Design Engineer's Acceptance of Completed Components
All daily inspection summary reports, inspection data sheets, problem
identification and corrective measures reports, and block evaluation reports
should be reviewed by the CQA officer and then submitted to the design
engineer. The reports should be evaluated and analyzed for internal consist-
ency and for consistency with similar work. Timely submittal of these
documents will permit errors, inconsistencies, and other problems to be
detected and corrected as they occur, when corrective measures are easiest.
The design engineer should assemble arid summarize the above information
into a periodic Design Acceptance Report. The reports should indicate that
the materials and construction processes comply with design specifications
and permit requirements. These reports should be included in project
records and, if requested, submitted to the permitting agency.
2.5.5 Final Documentation
At the completion of the project, the facility owner/operator should
submit a final report to the permitting agency. This report should include
all of the daily inspection summary reports, inspection data sheets, problem
identification and corrective measures reports, block evaluation reports,
photographic reporting data sheets, design engineers' acceptance reports,
deviations from design and material specifications (with justifying documen-
tation), and as-built drawings. This document should be prepared and
certified correct by the CQA officer and included as part of the CQA plan
documentation.
89
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2.5.5.1 Responsibility and Authority--
The final documentation should reemphasize that areas of responsibility
and lines of authority were clearly defined, understood, and accepted by
all parties involved in the project. Signatures of the facility owner/
operator, design engineer, CQA officer and construction contractor should
be included as confirmation that each party understood and accepted the
areas of responsibility and lines of authority and performed their func-
tion(s) in accordance with the CQA plan.
2.5.5.2 Relationship to Permitting Agencies--
Final documentation submitted to the permitting agency as part of the
CQA plan documentation does not sanction the CQA plan as a guarantee of
facility construction and performance. Rather, the primary purpose of the
final documentation is to improve confidence in the constructed facility
through written evidence that the CQA plan was implemented as proposed and
that the construction proceeded in accordance with design criteria, plans,
and specifications.
2.5.6 Storage of Records
During the construction of a hazardous waste land disposal facility,
the CQA officer should be responsible for the facility construction records.
This includes the originals of all the data sheets, reports, the design
engineer's acceptance of completed components reports, and facility drawings.
With the CQA officer in charge of the facility construction records, any
documentation problems should be noted and corrected quickly. Once facility
construction is complete, the document originals should be stored by the
owner/operator in a manner that will allow for easy access. An additional
copy should also be kept at the facility if this is in a different location
from the owner/operator's files. A final copy should be kept by the
permitting agency in a publicly acknowledged repository.
90
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REFERENCES
AASHTO. 1983. Standard Specifications for Transportation Materials and
Methods of Sampling and Testing, Part 2. American Association of
State Highway and Transportation Officials. Washington, DC.
ASTM: 1985a. Annual Book of ASTM Standards Vol. 04.08. Soil Rock and
Bldg. Stones. Philadelphia, PA.
ASTM: 1985b. Annual Book of ASTM Standards. Volume 14.02. General Test
Methods,...; Statistical Methods... American Society for Testing and
Materials. Philadelphia, PA.
Anderson, D. C. , J. 0. Sai, and A. Gill. 1984. Surface Impoundment Soil
Liners. Report to U.S. Environmental Protection Agency by K. W. Brown
and Associates Inc., EPA Contract # 68-03-2943.
AWWA. 1982. Standard for Installation of Water Main. C600-82. Section 4,
Hydrostatic Testing. American Water Works Association. Denver, CO.
Beaton, J. L. 1968. Statistical Quality Control in Highway Construction.
Jour, of the Construction Division. ASCE. Vol. 94. No. C01.
pp. 837-853.
Boutell, G. C., and V. R. Donald. 1982. Compacted Clay Liners for Indus-
trial Waste Disposal. Presented at ASCE National Meeting, Las Vegas,
NV. April 26, 1982.
Burr, I. W. 1976. Statistical Quality Control Methods. Marcel Dekker,
Inc. New York.
Chamberlin, E. J. 1981. Comparative evaluation of frost--susceptibility
tests. Transportation Research Record 809.
Daniel, D. E. 1984. Predicting Hydraulic Conductivity of Clay Liners. J.
of Geotech. Eng. 110(2):285-300.
Daniel, D. E., S. J. Trautwerin, S. S. Boynton, and D. E. Foreman. 1984.
.Permeability Testing with Flexible-Wall Permeameters. Geotechnical
Testing Journal. Vol. 7. No. 3. pp. 113-122.
Daniel, D. E., D. C. Anderson, and S. S. Boynton. 1985. Fixed-Wall Versus
Flexible-Wall Permeameters. In: Hydraulic Barriers in Soil and Rock.
American Society for Testing and Materials. ASTM STP 874, 329 pages.
91
-------
REFERENCES (continued)
Day, S. D. and D. E. Daniel. 1985. Field Permeability Test for Clay
Liners. In: Hydraulic Barriers in Soil and Rock American Society for
Testing and Materials. ASTM STP 874, 329 pages.
Deming, W. E. 1950. Some Theory of Sampling. John Wiley and Sons, Inc.,
New York.
Duncan, A. J. 1959. Quality Control and Industrial Statistics. Richard
D. Irwin, Inc. Homewood, Illinois.
E. C. Jordan Company. 1984. Assuring Quality in Leachate Collection
System Construction. Prepared for the Municipal Environmental Research
Laboratory, Office of Research and Development, U.S. EPA, under Contract
No. 68-03-1822.
Eorgan, J. D. 1985. Personal Communication with C. M. Northeim of the
Research Triangle Institute, RTP, NC.
EPA. 1983. Lining of Waste Impoundment and Disposal Facilities. SW-870.
U.S. Environmental Protection Agency. Cincinnati, OH.
EPA. 1985. Draft. Minimum Technology Guidance Document on Double Liner
Systems for Landfills and Surface Impoundments—Design, Construction
and Operation. U.S. Environmental Protection Agency. EPA/530-SW-85-014.
71 pages.
Gilman, E. F., F. B. Flower, and I. A. Leone. 1983. Standardized Procedures
for Planting Vegetation on Completed Sanitary Landfills. U.S. Environ-
mental Protection Agency, Cincinnati, OH. EPA-600/2-83-055. PB83-241-018.
Gordon, M. E. and P. M. Huebner. 1983. An Evaluation of the Performance
of Zone of Saturation Landfills in Wisconsin. Presented at the Sixth
Annual Madison Waste Conference, September 14-15, 1983. University of
Wisconsin.
Grant, E. L. 1964. Statistical Quality Control. 3rd. ed. McGraw-Hill
Book Co., Inc. , New York.
Haxo, H. E. 1983. "Analysis and Fingerprinting of Unexposed and Exposed
Polymeric Membrane Liners." In: Ninth Annual Research Symposium,
Land Disposal of Hazardous Waste. EPA-600/9-83-018, pp. 157-171,
Sept.
Herzog, B. L. and W. J. Morse. 1984. A Comparison of Laboratory and Field
Determined Values of Hydraulic Conductivity at a Disposal Site.
pp. 30-52. In: Proceedings of the Seventh Annual Madison Waste
Conference, University of Wisconsin-Extension, Madison, Wisconsin.
92
-------
REFERENCES (continued)
Holtz, W. G. 1965. Volume change in C. E. Black, ed. Methods of Soil
Analysis Part 1, Amer. Soc. of Agronomy, Madison, WI.
Horslev, M. J. 1943. Pocket-Size Piston Samplers and Compression Test
Apparatus, USAE Waterways Experiment Station, Vicksburg, MS.
Horz, R. C. 1984. Geotextiles for Drainage and Erosion Control at Hazardous
Waste Landfills (draft). Prepared by the U.S. Waterways Experiment
Station, Vicksburg, MS, for U.S. Environmental Protection Agency.
Interagency Agreement No. AD-96-F-1-400-1.
Kastman, Kenneth H. 1984. Hazardous Waste Landfill Geomembrane: Design,
Installation, and Monitoring. In: International Conference on Geo-
membranes Proceedings, Published by Industrial Fabrics Association
International, St. Paul, MN.
Kish, L. 1967. Survey Sampling. John Wiley & Sons, Inc., New York.
Knipschild, F. W., R. Taprogge, and H. Schneider. 1979. Quality Assurance
in Production and Installation of Large Area Sealing Sections of High
Density Polyethylene. Schlegel Engineering GmbH, Chelmsford, Essex,
United Kingdom.
Kotzias, P. C. and A. C. Stamatopoulos. 1975. Statistical Quality Control
at Kastraki Earth Dam. J. of the Geotechnical Engineering Division.
ASCE. Vol. 101; No.
Lanz, L. J. 1968. Dimensional Analysis Comparison of Measurements Obtained
in Clay with Torsional Shear Instruments. Master of Science Thesis,
Mississippi State University, Starkville, MS.
Mitchell, D. H. and G. E. Spanner. 1984. Field Performance Assessment of
Synthetic Liners for Uranium Tailing Ponds--A Status Report. Battelle
Pacific Northwest Laboratory. Richland, Washington. PNL-5005, pp.
31-42.
Morrison et al. 1982. Installation of Flexible Membrane Lining in
Mt. Elbert Forebay Reservoir. REC-ERC-82-2. U.S. Bureau of Reclama-
tion. Denver, CO.
NSF: National Sanitation Foundation. 1983. Standard Number 54 for Flexible
Membrane Liners. Ann Arbor, MI.
Page, A. L. (ed.). 1982. Methods of Soil Analysis, Part 2. Chemical and
Microbiological Properties, 2nd Edition. Part 9 in Agronomy. American
Society of Agronomy, Inc. Madison, WI.
93
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REFERENCES (continued)
Schmidt, Richard K., Ph.D. 1983. Specification and Construction Methods
for Flexible Membrane Liners in Hazardous Waste Containment. Gundle
Lining Systems, Inc., Houston TX. Technical Report No. 102.
Selig, E. T. 1982. Compaction procedures, specifications, and control
considerations. Earthwork Compaction Transportation Research Record.
p. 1-8. National Academy of Sciences.
Spigolon, S. J., and M. F. Kelley. 1984. Geotechnical Assurance of Con-
struction of Disposal Facilities. Interagency Agreement No. AD-96-F-
2-A077, Solid and Hazardous Waste Research Division, Municipal Environ-
mental Research Laboratory, U.S. Environmental Protection Agency,
Cincinnati, OH, EPA 600/2-84-040.
Terzaghi, V. and R. B. Peck. 1967. Soil Mechanics in Engineering Practice.
John Wiley and Sons, Inc. New York.
USBR: U.S. Bureau of Reclamation. 1974. Earth Manual, 2nd edition,
Washington, DC.
U.S. Department of the Army. 1977. Construction Control for Earth and
Rockfill Lams. EM 1110-2-1911, Washington, DC.
U.S. Department of the Army. 1970. Laboratory Soils Testing. EM 1110-2-
1906, W/Chl, Washington, DC.
U.S. Department of the Army. 1971. Materials Testing. TM-5-530. Washing-
ton, DC.
U.S. Department of the Navy. 1982. Foundations and Earth Structures.
NAVFAC DM-7.2. Naval Facilities Engineering Command, Alexandria, VA.
VanderVoort, John. 1984. Comprehensive Quality Control in the Geomembrane
Industry Schlegel Lining Technology, Inc., The Woodlands, TX.
Willenbrock, J. H. 1976. A Manual for Statistical Quality Control of
Highway Construction, Vols. 1 and 2. Purchase Order No. 5-1-3356,
Federal Highway Administration, Washington, DC.
94
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APPENDIX A. INSPECTION METHODS USED DURING THE CONSTRUCTION OF HAZARDOUS
WASTE DISPOSAL FACILITIES
Facility component
Factors
to be inspected
Inspection methods
Test method reference
Foundation
Dikes
Removal of unsuitable
mateH al ?
Proof rol11nc of
subgrade
Filling of fissures or
voids
Compaction of soil
backfill
Surface finishing/
compaction
Steri1ization
Slope
Depth of excavation
Seepage
Soil type (index
properties)
Cohesive soil consist-
ency (field)
Strength (laboratory)
Dike slopes
Dike dimensions
Compacted soil
Drainage system
Observation NA
Observation NA
Observation NA
(See low-permeability soil liner
component)
Observation NA
Supplier's certification NA
and observation
Surveying NA
Surveying NA
Observation NA
Visual-manual procedure ASTM D2488-84
Particle size analysis ASTM D422-63
Atterberg limits ASTM 04318-84
Soil classification ASTM D2487-83
Penetration tests ASTM D3441-79
Field vane shear test ASTM D2573-72
Hand penetrometer Horslev, 1943
Handheld torvane Lanz, 1968
Field expedient unconfined TM 5-530 (U.S.
compression
Unconfined compressve
strength
Triaxial compression ASTM D2850-82
Surveying NA
of Army, 1971)
ASTM D2166-66
Dept,
Surveying; observations
(See foundation component)
(See leachate collection system
component)
NA
Erosion control measures (See cover system component)
(continued)
95
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APPENDIX A (continued)
Facility component
Factors
to be inspected
Inspection methods
Test method reference
Low-permeability soil
1 iner
Coverage
Thickness
Clod size
Tying together of lifts
Slope
Installation of protec-
tive cover
Soil type (index
properties)
Moisture content
In-place density
Moisture-density
relations
Strength (laboratory)
Cohesive soil consist-
ency (field)
Observation
Surveying; measurement
Observation
Observation
Surveying
Observation
Visual-manual procedure
Particle size analysis
Atterberg limits
Soil classification
Oven-dry method
Nuclear method
Calcium carbide (speedy)
Frying pan (alcohol or
gas burner)
Nuclear methods
Sand cone
Rubber balloon
Drive cylinder
Standard proctor
Modified proctor
Unconfined compressive
strength
Triaxial compression
Penetration tests
Field vane shear test
Hand penetrometer
Handheld torvane
Field expedient unconfined
compression
Permeability (laboratory) Fixed wall
Flexible wal1
Permeability (field)
Large diameter single-ring
infiItrometer
Sai-Anderson infiltrometer
NA
NA
NA
NA
NA
ASTM D2488-84
ASTM D422-63
ASTM D4318-84
ASTM D2487-83
ASTM D2216-80
ASTM D3017-78
AASHTO T217
Spigolon & Kelley
(1984)
ASTM D2922-81
ASTM D1556-82
ASTM D2167-84
ASTM D2937-83
ASTM D698-78
ASTM D1557-78
ASTM D2166-66
ASTM D2850-82
ASTM D3441-79
ASTM D2573-72
Horslev, 1943
Lanz, 1968
TM 5-530 (U.S. Dept.
of Army, 1971)
EPA, 1983. SW-870
Daniel et al., 1984
Daniel et al., 1985
Day and Daniel, 1985
Anderson et al. , 1984
(continued)
96
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APPENDIX A (continued)
Facility component
Factors
to be inspected
Inspection methods
Test method reference
Flexible membrane liners
Susceptibility to frost
damage
Volume chanae
Thickness
Tensile properties
Tear strength
Bonding materials
Bonding equipment
Handling and storage
Susceptibility classifi-
cation
Consoliaomete' lunaisturoec
or remolded sample;
Thickness of unreinforced
plastic sheeting (para-
graph 8.1.3. deadweight
method—specifications for
nonrigid vinyl chloride
plastic sheeting
Thickness of reinforced
plastic sheeting (testing
coated fabrics)
Tensile properties of
rigid thick plastic
sheeting (standard method
test for tensile proper-
ties of plastics)
Tensile properties of
reinforced plastic sheet-
ing (Grab method A--
testing coated fabrics)
Tensile properties of thin
plastic sheeting
Tear strength of reinforced
plastic sheeting (modified
tongue tear method B--
testing coated fabrics)
Tear strength of plastic
sheeting (Die C--test
method for initial tear
resistance of plastic film
and sheeting)
Manufacturer1 s
certification
Manufacturer' s
certification
Observation
Chamberlin, 1981
holtz, 196E
ASTM D1593
ASTM D751
ASTM D638
ASTM D751
ASTM D882
ASTM D751
ASTM D1004
NA
NA
NA
(continued)
97
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APPENDIX A (continued)
Facility component
Factors
to be inspected
Inspection methods
Test method reference
Leachate collection system
• Granular drainage and
filter layers
Synthetic drainage and
filter layers
Seaming
Sealing around penetra-
tions
Anchoring
Coverage
Installation of upper
bedding layer
Thickness
Coverage
Soil type
Density
Ply adhesion of reinforced
synthetic membranes, bonded
seam strength in peel
(machine method. Type A
test methods for ruboer
properties, adhesion to
flexible substrate)
Bonded seam strength in
shear of reinforced plastic
sheeting (modified grab
method A—testing coated
fabrics)
Bonded seam strength in
shear of unreinforced
plastic sheeting (modified)
Observation
Observation
Observation
Observation
Surveying; measurement
Observation
Visual-manual procedure
Particle size analysis
Soil classification
Nuclear methods
Sand cone
Rubber balloon
Permeability (laboratory) Constant head
Material type
Manufacturer's certifica-
tion
ASTM D413
ASTM D751
ASTM D3083
NA
NA
NA
NA
NA
NA
ASTM D2488-84
ASTM D422-63
ASTM D2487-83
ASTM D2922-81
ASTM D1556-82
ASTM D2167-84
ASTM D2434-38
NA
Handling and storage
Coverage
Observation
Observation
NA
NA
(continued)
U.S. Environment-?! Protection Aaencil
Region V. Uorary **
230 South Dearborn Street
Chicago, Illinois 60604
98
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TE
Pipes
APPENDIX A (continued)
Factors
Facility component ' to be inspected
Overlap
Temporary anchoring
Folds and wrinkles
Geotextile properties
Inspection methods
Observation
Observation
Observation
Tensile strength
Puncture or burst
resistance
Tear resistance
Flexibi 1 ity
Outdoor weatherabil ity
Short-term chemical
resistance
Fabric permeability
Percent open area
Test method reference
NA
NA
NA
Horz (1984)
Horz (1984
Horz (1984)
Horz (1984)
Horz (1984)
Horz (1984)
Horz (1984)
Horz (1984)
Cast-in-place concrete
structures
Material type
Handling and storage
Location
Layout
Orientation of
perforations
Jointing
• Sol id pressure pipe
• Perforated pipe
Sampling
Consistency
Compressive strength
Air content
Unit weight, yield, and
air content
Form work inspection
Manufacturer's certifica-
tion
Observation
Surveying
Surveying
Observation
Hydrostatic pressure test
Observation
Sampling fresh concrete
Slump of portland cement
concrete
Making, curing, and testing
concrete specimens
Pressure method
Gravimetric method
Observation
NA
NA
NA
NA
NA
Section 4, AWWA C600-82
NA
ASTM C172
ASTM C143
ASTM C31
ASTM C231
ASTM C138
NA
(continued)
99
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APPENDIX A (continued)
Facility component
Electrical and
mecnamca1 equipment
Factors
to be inspected
Equioment type
Material type
Inspection methods
Manufacturer1 s
certification
Manufacturer1 s
certification
Test method reference
NA
NA
Cover system
Cover foundation
Low-permeability soil
barrier
Flexible membrane
barrier
Bedding layer
Drainage and gas
venting layers
Topsoil and vegetation
(erosion control
measures)
Operation
Electrical connections
Insulation
Grounding
As per manufacturer's
instructions
As per manufacturer's
instructions
As per manufacturer's
instructions
As per manufacturer's
instructions
Waste placement records/ Observation
waste placement process
Soil backfill (See foundation component)
(See low permeability soil liner component)
(See flexible membrane liner component)
(See flexible membrane liner component)
(See leachate collection system component)
NA
NA
NA
NA
NA
Thickness
Slope
Coverage
Nutrient content
Soil pH
Soil type; moisture
content
Vegetation type
Seeding time
Surveying
Surveying
Observations
Various procedures
Soil pH; lime requirement
NA
NA
NA
Page, 1982
Page, 1982
(See low-permeability soil liner component)
Supplier's certification;
observations
Supplier's recommendations;
observations
NA
NA
100
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