600285029
^ / '
TEST METHODS FOR DETERMINING
THE CHEMICAL WASTE COMPATIBILITY
OF SYNTHETIC LINERS
by
Joseph Tratnyek, Peter Costas,- and Warren Lyman
Arthur D. Little, Inc.
Acorn Park
Cambridge, Massachusetts 02140
Contract No. 68-01-6160; Work Order No. 16
Michael W. Slimak, Project Officer
Monitoring and Data Support .Division
Office of Water Regulations and Standards
U.S. Environmental Protection Agency
Washington, D.C. 20460
Robert Hartley, Work Order Manager
Solid and Hazardous Waste Research Division
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
August 31, 1984
-------
DISCLAIMER AND PEER REVIEW NOTICE
The information in this document has been
funded wholly or in part by the United States
Environmental Protection Agency under Contract Mo.
68-01-6160 to Arthur D. Little, Inc. It has been
subject to the Agency's peer and administrative
review, and it has been approved for publication as
an EPA document.
Mention of trade names or commercial products
does not constitute endorsement or recommendation
for use.
ii
-------
ABSTRACT
Flexible membrane liners (geomembranes) used to contain liquid
chemicals and leachate at waste containment sites are required to be
chemically resistant (compatible) to the liquid. In order to select a
liner for use as veil as judge its long-term reliability, Its chemical
resistance against the liquid(s) to be contained oust be known. The
measurement of compatibility Is a complex matter* because a variety of
physical and chemical interactions can occur, and compatibility
failure of a membrane has .never been adequately defined for this
application.
A search was made for test methods that would ascertain the
compatibility performance of liners. Disclosed methods and procedures
were examined and compared. Two tests being promoted for general
acceptance are NSF Standard No. 54 (a voluntary industry-generated
test) and the proposed EPA Test Method 9090. Several other tests
developed by liner manufacturers and researchers were found, as well
as those methods generally applied to pipes, bottles, film, plastics,
rubber sheeting and the like.
Although details of tests vary, all are laboratory tests in which
selected physical properties of the membrane are compared and evalu-
ated after contact with the liquid for specified p*rldd« ttf time. All
are tedious, time-consuming, and potentially costly...Useful data for
product specification and application are derived from these tests,
but none adequately addresses all issues and questions raised,
especially with regard to liner life-time prediction. Nor is any one
test universally accepted for use. A combination of compatibility
tests (e.g., immersion, stress-crack, and permeation) may be necessary
to fully characterize chemical resistance in specific cases. A
superior test(s) based on a comprehensive understanding of liner
compatibility remains to be developed.
Proposed are two levels of effort (immediately practical, and
long-term) directed at evaluating membrane compatibility. In the
first, a test methodology based on current protocols and methods would
be developed to provide three kinds of required information: short-
term (testing up to 30 days' exposure), intermediate (testing up to 4
months' exposure), and long-term (greater than 4 months' exposure).
In the second, research and test method development would be pursued
with the purpose of exploring new methods, techniques, apparatus,
etc., for better compatibility characterization.
iii
-------
ACKNOWLEDGMENTS
This report was prepared by Arthur D. Little,
Inc., Cambridge, Massachusetts, under a contract
with the Monitoring and Data Support Division of the
Office of Water Regulations and Standards, Environ-
mental Protection Agency. It was designed to
contribute to research studies and evaluation of the
use of flexible membrane liners (FML) in hazardous
waste disposal sites. We gratefully acknowledge the
guidance given to us by our Work Order Manager,
Robert Hartley, and several other individuals,
especially Robert Landreth of the Office of Research
and Development, Municipal Environmental Research
Laboratory. These individuals, plus Henry Haxo, Jr.
(Matrecon, Inc.) and FML industry representatives,
provided valuable information and comments that.
contributed to the success -of this effort.
We also acknowledge the significant help given
to us by many individuals and organizations in Che
technical community, including resin manufacturers;
liner manufacturers and installers; liner * users;
universities; consulting and testing companies;
industry, trade and professional associations; and
State, Federal, and international agencies. It is
impossible to list all of these individuals, many of
whom expended generous amounts of time and shared
significant information with us.
iv
-------
CONTENTS
DISCLAIMER AND PEER REVIEW NOTICE
ABSTRACT
ACKNOWLEDGMENTS
CONTENTS
FIGURES
TABLES
1.0 INTRODUCTION
1.1 BACKGROUND '
1.2 NEED FOR REVIEW AND ASSESSMENT
1.3 PURPOSE AND SCOPE
2.0 SUMMARY OF FINDINGS
2.1 CURRENT TEST METHODOLOGY AND LIMITATIONS
2.2 CONCLUSIONS,
3.0 RECOMMENDATIONS
4.0 GENERAL TECHNICAL CONSIDERATIONS
4.1 NATURE OF LINER MATERIALS
4.2 NATURE OF CHEMICAL/LEACHATE
4.3 NATURE OF CHEMICAL COMPATIBILITY
4.4 COMPATIBILITY MEASUREMENT FEATURES
5.0 PRESENT COMPATIBILITY TESTS
5.1 BACKGROUND ^ «-• ,.-..-
5.2 TEST METHODS
5.3 COMPARISON OF TEST METHODS
ii
iii
iv
v
vii
viii
1
1
2
2
4
4
4
7
9
9
10
16
17
19-
19
20
22
5.3.1 ISO 175 - Plastics - Determination
of the Effects of Liquid Chemical
including Water 28
5.3.2 ISO 1817 - Vulcanized Rubbers -
Resistance to Liquids 30
5.3.3 DIN 53 521 - Determination of Resistance
to Liquids, Vapors, and Gases 31
5.3.4 DIN 53 532 - Permeability of Elastomer
Sheeting to Liquid Fuels 33
5.3.5 BS 4618 - Chemical Resistance of Plastics
to Liquids 34
5.3.6 BS 5173 - Hoses - Chemical Resistance Tests 36
5.3.7 EPA Method 9090 - Compatibility Test for
Wastes and Membrane Liners 37
5.3.8 NSF Standard 54 Flexible Membrane Liners 40
5.3.9 ASTM D543 (78) - Resistance of Plastics
to Chemical Reagents 43
5.3.10 ASTM D814 - Rubber Property - Vapor
Transmission of Volatile Liquids 45
5.3.11 ASTM G20 - Chemical Resistance of
Pipeline Coatings 46
5.3.12 ASTM D471 - Rubber Property - Effect
of Liquid 48
-------
CONTENTS (continued)
5.3.13 MIL-T-6396D Aircraft Tanks - Fuel,.Oil,
Water-alcohol, Coolant • . 50
5.3.14 Schlegel Test for HDFE * 51
5.3.15 J.P. Stevens Test . 53
5.3.16 Gundle Test ' 54
5.3.17 Simulation Test (Haxo) . 55
5.3.18 Pouch Test (Haxo) 56
5.3.19 Tub Test (Haxo) 57
5.3.20 Immersion Test (Haxo) 53
5.3.21 NSF's FML Project 59
5.3.22 Harwell Assessment of two HDPE Landfill
Liners by Application of an Accelerated
Test 61
5.3.23 Sequential Chemical Absorption Techniques
for Evaluating Elastomers 63
5.3.24 Guide to Fluid Resistance of Rubber and
Elastomers 64
5.3.25 Environmental Stress-cracking by Creep
Rupture Tests 65
5.3.26 Chemical Stress Relaxation Test 66
• 5-3.27 A New Method for Determining Environmental
Stress-crack Resistance of Ethylene-based
Plastics - 68'
5.4 TEST STATE-OF-THE-ART WT^*»« 70
5.5 CONSENSUS MEETING " 71
5.6 MINUTES OF MEETING ON COMPATIBILITY TEST METHODS
AND FML REQUIREMENTS • 72
5.6.1 Exposure Conditions 72
5.6.2 Test Methods 74
5.6.3 Cost Profile 75
5.7 TEST EQUIPMENT AND COST CONSIDERATIONS 76
6.0 GENERAL APPROACH TO COMPATIBILITY TESTING 78
6.1 THE SCOPE OF TESTING 78
6.1.1 FML Material versus Liquid Challenge 78
6.1.2 Parameters 80
6.1.3 Measurements and Observations 81
6.1.4 Test Details 82
6.2 THE CURRENT DILEMMA AND ROUTES TO RESOLUTION 83
REFERENCES 91
APPENDIX A 97
vi
-------
FIGURES
Number • • Page
5.1 ISO 175 ' 29
5.2 DIN7 53 521 ' 32
5.3 BS 4618 35
5.4 METHOD 9090 39
5.5 NSF STANDARD 54 42
5.6 ASTM D543 44
5.7 ASTM G20 47
5.8 ASTM D471 49
5.9 SCHLEGEL 52
5.10 NSF's FML PROJECT 60
5.11 HARWELL REPORT •••-**•*.•. fc£ '
5.12 CHEMICAL-STRESS RELAXATION 67
5.13 ENVIRONMENTAL STRESS-CRACKING OF
ETHYLENE PLASTICS 69
6.1 THE COMPATIBILITY TEST SCHEME 79
6.2 DETAILED SECTION THROUGH A VESSEL 85
6.3 STRESS RELAXATION CLASSIFICATION 86
6.4 DMA - UNEXPOSED HOPE 88
6.5 DMA - EXPOSED HDPE 89
vii
-------
TABLES
Number'
4.1 LABORATORY TEST CHEMICALS
4.2 MISCELLANEOUS TEST PRODUCTS
4.3 COMPOSITION OF THREE SELECTED LANDFILL LEACHATES
4.4 POTENTIAL ORGANIC CHEMICALS IN WASTE LIQUIDS
4.5 AVERAGE DATA FROM SEVEN DIFFERENT INDUSTRIAL
LEACHATES
5.1 KEY WORDS USED IN LITERATURE SEARCH
5.2 INTERNATIONAL STANDARDS AND TESTS
5.3 NATIONAL STANDARDS AND TESTS
5.4 INDUSTRIAL STANDARDS AND TESTS
5.5 PROJECT TESTS '
5.6 SELECTED ACADEMIC/LITERATURE TESTS
5.7 TENSILE AND TEAR TESTING PROTOCOLS
5.8 ' TEST METHODS
11
12
13
14
15
21
23
24
25
26
27
38
41
viii
-------
1.0 INTRODUCTION
1.1 BACKGROUND
The U.S. Environmental Protection Agency (EPA) published interim
final regulations for the land disposal of hazardous wastes on
July 26, 1982. These regulations became effective on January 26,
1983. The regulations specify design and operating standards relating
to the use of liner and cap systems for the purpose of waste contain-
ment .
While the liner and cap systems may be based on compacted clays,
admixtures (e.g.. concrete and asphalt), and soil sealants* liners
fabricated from synthetic polymer materials (often referred to as
flexible membrane liners - FML*) will be used at a large number of the
waste sites. The preamble to 40 CFR, Parts 122, 260, 264, and 265
(U.S. EPA, 1982), states that "in the cases of ^landfills and of
surface impoundments used to dispose of hazardous waste, the regula-
tions provide that the liner must be constructed of materials that
prevent wastes from passing into the liner. Synthetic liners are the
only commonly used materials of which EPA is aware that would meet
.this standard." .
Since the primary function of a Iiner4<^s^to^pntain waste-
liquids, a priori, a liner must be resistant to^^Wftfttid. A key
issue in the use of an FML is its compatibility (chemical resistance)*
with the waste liquid it will hold. The criteria for evaluating
chemical resistance and the choice of test methods are part of that
issue.
Although compatibility data derived from field tests constitute
actual use data, most data, by necessity, are obtained from laboratory
tests. Field information is preferred because, it reflects "real"
exposure. As a matter of fact, adequate field data have not been
generated because the use of FML for waste containment is too new a
technology (in the order of 20 years of experience). Although field
information is currently being generated, field testing is a slow
process. To expedite the evaluation and selection of an FML, data are
obtained from laboratory tests in which an FML is exposed to a chemi-
cal challenge under set conditions, and then properties—usually
physical—of the exposed FML are measured. Laboratory tests serve as
the primary screening approach to FML chemical compatibility evalu-
ation.
*The currently used term "geomembrane" includes FML. In FML tech-
nology, a "compatible" liner is generally accepted as one that is
"resistant" to chemical attack as Judged by its changes in physical
properties upon exposure to liquid waste.
-------
A detailed introduction to the FML industry, liner issues, and
testing in general, including chemical compatibility, is found in
other sources (Refs. 1-4).
1.2 NEED FOR REVIEW AND ASSESSMENT
For the benefit of regulators, planners, and designers, the
current test methodology requires review and assessment so that
uncertainties about data can be minimized. Chemical resistance data
are needed for FML product development, screening purposes, site
liner-waste matching, and liner life prediction. Although standard
compatibility tests are being proposed or promulgated (e.g., NSF 54
and EPA 9090), a variety of other'tests available within the FML
industry and/or plastics and rubber industries are currently in use.
The meaning and value of data derived from the tests are unclear
because of differences in technique. All the applicable tests have
never been compared to see how they differ, or if one is more infor-
mative than another. This report attempts to review identified
compatibility tests pertinent to FMLs and assesses them in relation to
chemical resistance measurement and the required needs for FML
products.
1.3 PURPOSE AND SCOPE - ;
The purpose of this assignment was to compile, review, and
evaluate available test methods for measuring ><9
-------
Finally, a meeting was held at Arthur D. Little, Inc., in
Cambridge, Massachusetts. In attendance . vere industrial and
Government experts in FML technology and testing. A goal of this
meeting was to develop a consensus about compatibility testing.
-------
2.0 SUMMARY OF FINDINGS
2.1 CURRENT TEST METHODOLOGY AND LIMITATIONS
Current test methodology has evolved from metal corrosion testing
and rubber and plastic testing. All current tests, even with their
variation in details, fall into a pattern of 'contacting the membrane
with the liquid for specified periods of time, followed by examination
of the FML appearance, measurement of weight and dimensional change,
as well as measurement of stress-strain properties (e.g., tensile
strength, elongation, modulus). Alternative methods of exposure
include simple suspension of the FML in liquid, one-side liquid
contact of the membrane fixed in a cell, exposure in a dish to simu-
late ponding, and pouch testing in which waste is enclosed in the FML.
Hardness and puncture resistance may also be measured. Stress-
cracking, an important failure mode for some polyethylene-based
membranes* may be measured as well. Because no good test method
exists for tear resistance, this property is difficult to deal with,
especially in the case of fabric-reinforced FML. However, tear
resistance is often measured.
There are problems with current methodology. Most tests produce
only indirect indication of FML chemical resistance, and important
parameters are neglected or minimized in FML product evaluation. No '
actual determination of chemical change is made in routine testing.
In the absence of true long-term data from field or laboratory (the
FML technology is too new), current compatibility data, in conjunction
with industrial experience, must be used to Judge future behavior of
FML. Lack of correlation with field performance remains a present
issue. The experience baseline with complex waste compositions and
their often unpredictable behavior is limited, and current physical
tests may measure properties that are only partial indicators of
actions taking place between membrane and liquid. Although attention
in testing is focused on the chemical constituents of waste, the role
of water (an active aggressor and catalyst by itself) is frequently
overlooked or underestimated. Mass transfer of liquid (permeation)
through an FML is not often measured and, until recently, has not been
considered an important parameter for FML product evaluation.
Permeation testing is considered separately from compatibility
testing; it involves different test procedures.
2.2 CONCLUSIONS
1. Presently there is no generally accepted test method that
fully meets the needs of industry or regulatory agency for
the chemical compatibility assessment of FML in the presence
of waste liquid.
-------
2. Only two general test methods, recently Introduced, deal
specifically with chemical compatibility testing of membrane
liners. They are: NSF Standard 54 «nd EPA Method 9090.*
NSF 54 offers a recommended test method for long-term perfor-
mance of membrane liners in a chemical environment. The
"long-term" evaluation is based on extrapolation from very
short-term measurement. Method 9090, a proposed method, is
used in determining the effects of chemicals in a pit, pond,
lagoon, or landfill-type installation on the physical prop-
erties of FML materials intended to contain them. Both tests
evaluate chemical compatibility indirectly by the measurement
of changes in several physical properties after exposure.
Both tests incorporate standard ASTM methods for testing
mechanical properties of rubber and plastics. Neither test
deals directly with permeability nor environmental stress-
cracking. (The NSF document contains a stress-crack require-
ment in the specifications, but it is not part of compati-
bility evaluation.) Because of sampling requirements, the
more elaborate test protocol, the need for special exposure
apparatus, and longer specified time for testing, Method 9090
is a more complex test than NSF 54 and would be more costly
to run.
3. Chemical compatibility testing in the laboratory is conducted
with actual leachate, waste, or reagent, ^^ftaagent testing is
preferred for screening, but all current methods specify
exposing the test specimen to actual waste samples or
leachate. Exposing test specimens in an actual waste
containment facility is recommended, and provision for
inclusion of membrane coupons at the site for periodic
examination for compatibility appears to be an obvious
prerequisite for obtaining real data over the long term.
Chemical class lists versus the FML type developed by
industry and investigators for tests appear to be adequate
for the initial stages of selecting an FML for a specific
site.
r
4. FML chemical compatibility testing is made complex because of
a large variety of possible interactions among components of
the process. Figure 6.1 (p. 79) gives a schematic overview
of this complexity.
5. Compatibility testing is tedious, time-consuming, costly, and
potentially dangerous due to the need for handling toxic
substances. The ideal route to testing has not yet been
established, and long-term prediction is tenuous because of
incomplete knowledge.
*A revised version of Method 9090 was released by EPA in October,
1984. See NOTE on p 37.
-------
6. Current tests, including those discussed above, deal with
only part of the compatibility problem. The broader issue
includes questions about practicability* cost, time span,
significance, and reliability.
7. It appears that there will be no immediate and ideal
resolution of the FML chemical compatibility test issue. It
is obvious that NSF 54 and Method 9090 are the current
contenders for a standard test method, since other tests have
not been developed sufficiently for FML evaluation. * However,
whether NSF 54 is followed, Method 9090 is imposed, other
methods surface, or industry goes its own way, the problems
are too diffuse and complex to rely on a simple set of rules
as presently conceived. The crux of the problem is related
to the need for good long-term data in what is essentially a
new industry, and the fact that chemical compatibility
indicators remain undefined. Truly reliable compatibility
data will be generated with time, but continuous action is
required by industry, regulatory agencies, and the research
community to define the requisite parameters for evaluation,
and then to develop the appropriate tests.
-------
3.0 RECOMMENDATIONS
Effort on two levels is needed to evaluate FMLs for waste liquid
containment. The first level of effort deals with the immediate
practical issue of ascertaining FML compatibility for a particular
application. The second—of long-term nature—focuses on under-
standing FML compatibility in the chemical/physical context, and then
devising test methods for measuring the identified parameters. The
first relies on maximizing application of current tests. The second
explores new or untested methods.
For the first approach, it is recommended that test protocol be
developed that would provide three kinds of information which might
satisfy industry and regulatory body needs to the different degrees
required:
1. Short-term tests (up to 30 days' exposure),
II. Intermediate tests (up to 4 months' exposure),
III. Long-term tests (greater than 4 months' exposure).
Level I data would be used to screen FML/liquid combinations for
FML development and for selection purposes; Level II data would
provide significantly more data related to expected life and real
performance; and Level III data would provide confirmation of compati-
bility and correlation with performance goals.
All three levels of testing can be conducted with known current
or proposed methodology. Details of testing might vary, but suffi-
cient guidelines are already in place in the currently cited tests.
Membrane actually exposed in the waste site should be tested to
confirm laboratory evaluation. In addition to the basic physical
testing, stress-crack measurements should constitute an additional
requirement for testing polyethylene-based polymer membranes. The
test matrix in Section 5.6.2 (p. 74) summarizes requirements for
physical testing of current FML.
The approach to testing using current methods discussed in the
text (e.g., EPA 9090, NSF 54, ASTM D543, ASTM D471, ISO 175, DIN
53-521, BS 4618, etc.) should be recognized as providing only an
abbreviated assessment of chemical compatibility. Other properties
not now part of a standard compatibility test may be useful or even
better indicators. In the second approach to establishing the
chemical resistance of FML, an exploratory course is called for in
which FML properties are evaluated with techniques not now employed
for compatibility measurement. Information about visco-elastic
behavior and permeability obviously should be included. Methods for
measurement of dynamic stress-strain properties, dynamic mechanical
analysis, torsional stress, and thermal properties, especially under
stress or load, are examples of techniques that might be explored
further.
-------
It is recommended that, besides pursuing practical compatibility
testing on the three levels above, research be conducted to evaluate
other techniques and approaches.
-------
4.0 GENERAL TECHNICAL CONSIDERATIONS
Before dealing with specific test methods, a variety of general
technical considerations should be reviewed. It is important to be
aware of these factors that play a role in determining chemical
compatibility, so that test methods might be better assessed later.
4.1 NATURE OF LINER MATERIALS
Commonly available industrial liner products are constituted
principally of the following chemical polymeric materials:
Polyvinyl chloride (PVC);
Polyethylene, low-density (LDPE) and high-density (HDPE);
Chlorinated polyethylene (CPE);
Chlorosulfonated polyethylene (CSPE, CSM);
Ethylene propylene rubber (EPDM);
Epichlorohydrin rubber (ECO);
Neoprene rubber (CR);
Butyl rubber (IIR)
Asphalt/bitumen (A/B).
Asphalt/bitumen and admixes with inorganic aggregate and other.
polymers, although useful in water containment, play a minor role in
hazardous waste containment. They are not considered 4Ln this document
due to lack of information about them relative to test methods.
All the above polymeric materials and FML products made from them
vary in degree of resistance to a specific chemical. A compendium of
currently available compatibility data is being prepared in another
study (Ref. 5).
It is important to understand that these polymers are compounded
alone and in blends with additional materials and chemicals to achieve
specific liner properties such as flexibility, ozone and UV resis-
tance, and oil or water resistance. The liner membrane may vary in
thickness (e.g., 30-120 mils), may be pigmented In different colors,
may be a laminate, or may be reinforced with fiber scrim. Reinforcing
fiber is usually polyester or nylon. Nevertheless, in trade parlance,
the chemical polymer (the major constituent) is used to identify the
type of liner. From a practical point of view, within each .class of
polymer manufacturers have made available a range of grades that are
interactively overlapping with other polymers.
Although the behavior of a compounded FML will depend upon its
total composition, the fundamental behavioral element will be the
polymer phase. Therefore, the 'polymer has to be selected for its
chemical resistance in a specific application. Chemical resistance
will depend not only upon the chemical makeup of the polymer, but also
-------
on other factors, such as degree of polymerization or molecular
weight, degree of crosslinking , cry stallinity , morphology, and the
like.
Polymer chemistry and properties are discussed in many textbooks
on the subject and need not be detailed here. In addition, product
literature is available from manufacturers and suppliers. For a
concise, state-of-the-art treatment of polymer chemistry, the reader
is referred to the literature (Ref. 6).
4.2 NATURE OF CHEMICAL /LEACHATE
The nature and composition of the waste liquid challenging the
liner may be infinite in variation. While water and selected organic
liquids can be chosen to challenge the membrane alone* combinations of
liquids and other waste material may also be used. Dissolved salts
and other materials may be found in the challenge liquid. In the
field, actual leachate/waste at a site is usually a complex mixture of
many components. It may be difficult to analyze and characterize
because of multiphase components or immiscible material. In any case,
mixtures frequently do not behave in a manner predicted from compo-
nents .
A number of the test procedures specify the liquids to be used.
Not all tests use the same liquids. To illustrate, Tables 4.1 and 4.2
describe liquids specified in ISO 175 (International Standard-
Plastics— Determination of the Effects of Liquid Chemicals, including
* ' '"
Leachate represents an actual liquid composition apt to be
experienced in the field. However, leachate components may change
over a period of time, and the composition of the leachate does not
remain constant. Ko standard leachate for testing has been identified
or agreed upon. Industrial wastes may be acidic or alkaline, oxidiz-
ing or reducing, or may be brine, or oily, and contain heavy metals,
pesticides, and such. Waste liquids may be classified as aqueous-
inorganic, aqueous-organic, organic, or sludge.
Leachate composition and characteristics have been investigated
and are reported elsewhere. Shuckrow et al. review information on
leachate (Ref* 7) and TRW has compiled comprehensive data on hazardous
waste leachate (Ref. 8). The TRW study covers 30 different leachates
from some 11 landfills. Leachate is discussed in conjunction with
membranes by the EPA (Ref. 9). Leachate per se is considered to be a
dilute solution of inorganic and organic components in water. It may
be acidic or basic, act as an oxidizing or reducing agent, or function
as a solvent or plasticizer. Tables 4.3, 4.4, and 4.5 illustrate the
complexity of leachate and the type of components that might be
expected in the liquid. Other combinations of ingredients can be
found.
10
-------
TABLE 4.1. LABORATORY TEST CHEMICALS
Test Liauid
Concentration
X(vt.)kg/m
Acetic acid 99.5
Acetic acid 5 50
Acetone 100
Ammonium hydroxide solution 25 230
Ammonium hydroxide solution 10 96
Aniline 100
Chromic acid solution 40 550
(as CrO )
Citric acid solution 10 100
Diethyl ether 100 —
Distilled water 100 —
Ethanol — 770
Ethanol 50 460
Ethyl acetate 100 —
n-Heptane 100
Hydrochloric acid 36
Hydrochloric acid 10 105
Hydrofluoric acid 40 450
Hydrogen peroxide 30 330
Hydrogen peroxide 3 31
Comments
Concentrated
Add 50 ml of concentrated acetic
acid to 950 ml water
Expressed as ammonia (NH.)
Expressed as ammonia (NIL)
Add 3 ml of concentrated sulphuric
acid per liter of solution
962 (V/V) (71° 0.P.)
1000 ml of 96% (V/V) ethanol and
740 ml water
Concentrated
Add 250 ml of concentrated hydro-
chloric acid to 750 ml of water
Not diluted
10 volumes of 30* (V/V)
.90 volumes of water
and
Lactic acid 10 100 —
Methancl 100
Nitric acid 70 ~
.Nitric acid 40 500
Nitric acid 10 105
Oleic acid 100 t —
Phenol solution 5 50
Sodiun carbonate solution 20 216
Sodium carbonate solution 2 20
Sodium chloride solution 10 108
Sodium hydroxide solution 40 575
Sodium hydroxide solution 1 10
Sodium hypochlorite solution 10 —
Sulphuric acid 98
Sulphuric acid 75 1250
Sulphuric acid 30 366
Sulphuric acid 3
Toluene 100
2,2,4-Trimethylpentane ' 100
(iso-octane)
Concentrated
Add 500 ml of concentrated nitric
acid to 540 ml of water
Add 105 ml of concentrated nitric
acid to 900 ml of water
Expressed as Na.CO •10H,0
9.5Z active chlorine
Concentrated
Add 695 ml of concentrated
sulphuric acid to 420 ml of water
Add 200 ml of concentrated
sulphuric acid to 850 ml of water
Add 17 ml of concentrated
sulphuric acid to 990 ml of water
Source: ISO 175 (Ref. 25).
11
-------
TABLE 4.2. MISCELLANEOUS TEST PRODUCTS
Test Liquid
Mineral oil
Insulating oil
Olive oil
Cotton seed oil
Solvent mixtures
Soap solution
Detergent
Essence of turpentine
Kerosene
Petrol (gasoline)
Source: ISO 175 (Ref. 25).
12
-------
TABLE 4.3. COMPOSITION OF THREE SELECTED LANDFILL LEACHATES
Constituent
Concentration (mg/1)
Total solids
Volatile suspended solids
Total suspended solids
Total volatile acids as acetic acid
Acetic acid
Propionic acid
Butyric acid
Valeric acid
Organic nitrogen as N
Ammonia nitrogen as N
Kjeldahl nitrogen as N
PH
Total alkalinity as CaO>3
Total acidity as CaCO.
Total hardness as CaCO.
Chemical and metals:
Arsenic
Boron
Cadmium
Calcium
Chloride
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Phosphate
Potassium
Silica
Sodium
Sulfate
Zinc
36,250
—
—
~
—
—
—
—
—
950
1,240
6.2
8,965
5,060
6,700
•
— -
—
—
2,300
2,260
—
—
1,185
—
410
58
—
—
82
1,890
—
1,375
1,280
67
12,500
76
85
9.300
5,160
2,840
1,830
1,000
107
117
—
5.1
2,480
3^60
5,555
—
—
—
1,250
180
—
— —
185
__
260
18
~
— _
1.3
500
~
160
~
— _
—
—
333
—
~
—
—
—
862
—
6.9
—
—
—
0.11
29.9
1.95
354.1
1.95
<0.1
<0.1
4.2
4.46
233
0.04
0.008
0.3
__
__
14.9
748
<0.01
18.8
Note: — means "not measured"
Source: EPA (Ref. 9).
-------
TABLE 4,4. POTENTIAL ORGANIC CHEMICALS IN WASTE LIQUIDS
Organic Chemicals
Type
Acid
Acid
Base
Base
Neutral-polar
Neutral-polar
Neutral-polar
Neutral-polar
Neutral-polar
Neutral-nonpolar
Neutral-nonpolar
Neutral-nonpolar
Neutral-nonpolar
Water
Aliphatic
Phenolic
Aromatic amine
Alkyl amide
Alcohol
Aldehyde
Alkyl halide
Ketone
Glycol
Alkane
Aromatic
Alkyl benzene
Mixed alkane
Name
Acetic acid
Phenol
Aniline
Formamide
Methanol
Butyraldehyde
Chloroform
Acetone
Ethylene glycol
-•^tipiane
Benzene
Xylene
Paraffin oil
Source: EPA (Ref. 9).
14
-------
TABLE 4.5. AVERAGE DATA FROM SEVEN DIFFERENT INDUSTRIAL LEACHATES
Constituent
Chromium
Iron
Arsenic
Mercury
Cobalt
Copper
Nickel
Manganese
Cadmium
Zinc
Selenium
PCBs
Methylene chloride
Trichlorofluoroethane
1,1-Dichloroethene
1,1-Dichloroethane
Trans-1,2-Dichloroethene
Chloroform
1,2-Dichloroethane
1,2,1-Trichloroethane
•Carbon Tetrachloride
Bromodifluoromethane
1,2-Dichloropropane
Trans-1,3-Dichloropropene
Trichloroethene
Cis-1,3-dichloropropene
1,1,2-Trichloroethane
Benzene
Bromoform
Tetrachloroethene
1,1,2,2-Tetrachloroethane
Toluene
Chlorobenzene
Ethylbenzene
Chlorodibromomethane
Highest
Average
Concentration
(mg/1)1
0.87
164
120
0.040
1,
1,
4,
22
62
02
89.4
125.5
3.95
<0.005
4.05
11.8
0.14
0.05
0.70
4.65
1,
2,
.91
,12
0.24
0.039
0.039
0.035
.050
.69
0.050
0.050
1.06
0.038
0.60
0.75
1.73
0.33
0.48
<0.001
0,
1
Concentration
Rank?
17
1
3
26
15
14
8
4
2
9
30
7
5
24
25 •
19
.6
11
10
23
27
29
25
13
25
25
16
28
20
18
12
22
21
31
NOTES:
1. Highest average concentration is equal to the greatest concentration
value reported for the constituent in any of the seven leachates.
2. Concentration rank of 1 means that the highest average concentration
of the given constituent is greater than all other highest average
concentrations for other constituents detected.
Source: TRW (Ref. 8).
15
-------
Examination of the tables shows that some inorganic constituents
appearing in high concentrations in the reported leachates are iron,
calcium* manganese, cadmium, and arsenic; and that the organic
constituents identified in high concentrations are acetic acid,
methylene chloride, butyric and propionic acids, dichloroethanes, and
chloroform. The organic compounds by themselves are good solvents.
Obviously each leachate or waste liquid requires chemical analysis for
Identification of constituents and characterization. Permeation of
liquid is said to have occurred when liquid penetrates the polymer.
Whether or not liquid is transported through the membrane depends upon
the concentration gradients and other factors in the environment.
A.3 NATURE OF CHEMICAL COMPATIBILITY
Within the FML industry, a "compatible" FML material is generally
accepted as one that is resistant to chemical attack as judged by its
changes in physical properties after exposure to the waste. However,
the chemical attack can take place via several routes, all of which
can be mutually interactive. They are:
• Chemical reaction,
• Hydrolysis,
• Solvation/plasticization,
• Environmental response (heat, light,
ozone, bio-'-organism, etc.).
In chemical reaction, direct reaction of the reagent with active
sites on the polymer chain is involved. Subsequent molecular chain
scission, addition, or crosslinking may occur. The rate of reaction
depends on the polymer and the reagent and, like all chemical reac-
tions, it is greatly affected by temperature and reagent concentra-
tion.
Hydrolysis is concerned with the sensitivity and reactivity of a.
polymer with water. It is a special case of chemical reaction. Since
leachate is mostly water, and water cannot be avoided in the environ-
ment, it is required that the polymer be little affected by water.
However, in the presence of water, the deleterious effects of other
chemicals such as ionic species and partially soluble organic
substances are frequently accelerated, especially when the polymer
sorbs water. Water can act as a carrier for harmful ingredients to
the polymer.
Solvation is similar to chemical attack in that an aggressive
material, usually an organic solvent, can enter the polymer,
dissociate bonds, and reduce it to a solution. Plasticization is a
lover degree of solvation in which the solvent is not fully miscible
with the polymer. Swelling of a polymer in a solvent is a form of
solvation since the chemical has entered the polymer's physical
structure.
16
-------
The environment can affect compatibility by accelerating liquid
penetration or chemical reaction. Heat, ultraviolet light, ozone, and
some organisms can cause an attack on polymers. Environmental stress-
cracking is a form of chemical attack in which a chemical that does
not appreciably attack or dissolve a polymer in the unstressed state
will cause catastrophic failure when the polymer is stressed in its
presence. Initiation and propagation of cracks and crazes occur prior
to physical failure. Stress-cracking phenomena are a potential
problem vith some varieties of HDPE and other semi-crystalline poly-
mers.
Mechanistic aspects of polymer reactions and degradation are
discussed in detail in texts concerning the subject and need not be
discussed here (Refs. 10-12).
It is important to remember that although we are dealing specifi-
cally with tests for chemical compatibility, FML chemical resistance
is influenced or altered by all factors capable of producing polymer
degradation:
Thermal,
Mechanical,
Photo and high-energy radiation.
Biological,
,. '. . -• -i*«fr«*«s»;* •-*
Enzymatic, and
Chemical.
The definition of compatibility or chemical resistance is therefore
open to interpretation. In the present case, we will deal with direct
reagent or liquid chemical interaction with FML.
4.4 COMPATIBILITY MEASUREMENT FEATURES
A variety of properties has been proposed and used for evaluating
membranes. Predicted serviceability has been based on the properties
assumed to be indicators of durability. Of primary interest is
resistance to chemicals in waste liquids. Chemical resistance or
compatibility is usually based on physical test data gathered after
exposure to a chemical or leachate. Physical test data may include
tensile properties such as tensile strength, yield strength, elonga-
tion at break, elongation at yield, and some others. These are one-
dimensional, short-term, simple tests that are easily accomplished in
the laboratory, and that are preferred by the industry as service
indicators. Additional physical tests may include tear and puncture
resistance of the membrane, hardness, and, in the case of a reinforced
membrane, ply adhesion tests.
Current methods that have evolved within the rubber and plastics
industries are primarily static in principle, that is, samples of FML
are not stressed during exposure. Specimens are simply contacted with
17
-------
chemical under set conditions. -Then physical measurements are made.
In a waste site, some degree of stress or load must be expected on the
FML, even though the FML does not function as a load-bearing material
in the engineering sense. Site .stresses are not easily -identified,
nor quantified. Methods in which the specimen is dynamically stressed
during the test may provide relevant information about compatibility
behavior more realistically.
The method of exposing specimens (e.g., immersion vs. one-surface
exposure) needs to be considered in testing and presently is a matter
of choice. Laminated and reinforced membrane materials require
different handling from homogeneous membranes.
Presently the industrial approach for assessing serviceability
rests upon measuring selected physical characteristics and upon
qualitative observation. Benchmark data are primarily derived from
unexposed product, and comparison is made to products exposed to the
environment or chemical. From this approach, chemical compatibility
data and specifications for membranes have evolved. The underlying
measurements and observations are those that are most easily made, not
necessarily the most relevant. The benchmark data are product-
specific and become the standard for comparison, even though their
applicability to.real service is not fully demonstrated.
Testing is not generally conducted with an engineering safety
factor or reliability factor in mind. Traditionally, in engineering,
material strength safety factors range from 2sI«tor*6i0tl* depending
upon materials and requirements. In fact, to achieve a degree of
safety, fabric-reinforced membrane is recommended by some FML
suppliers. However, the argument for reinforced membrane is based
more on circumstantial experience than on measured effectiveness,
although some polymers, e.g., CSPE, require fabric reinforcement in
most applications due to shrinkage and low modulus when warm.
While it is fairly well accepted that a material that exhibits
dramatic changes in physical properties upon exposure to a waste is
incompatible, reliable criteria for compatibility have not been
established. Field data that support the laboratory measurements are
being developed (Ref. 13).
Permeation measurements have been urged by A.D. Schwope (Ref. 2)
as an additional means of quantifying the barrier effectiveness of
FMLs. The ability of a membrane to restrict or permit migration of a
reagent from one side of the membrane to the other without physically
destroying the membrane requires serious consideration as a feature of
the chemical compatibility test protocol. Haxo recently reported on
the permeability testing of polymeric membrane lining materials
(Ref. 14). August and Tatzky (Ref. 15), as well as J.P. Giroud
(Ref. 16) have also done work in permeability measurement.
18
-------
5.0 PRESENT COMPATIBILITY TESTS
5.1 BACKGROUND
The chemical compatibility of polymeric material is an important
issue not only for the FML industry, but also for the bottle, package,
and pipe industries, whenever aggressive or corrosive liquids must be
contained. Test methods for determining the compatibility or chemical
resistance of a material are used to evaluate polymers in all these
industries. All of these industry tests have ouch in common, having
evolved from technological testing in the rubber and plastic indus-
tries. In its simplest form, the containment material is exposed to a
liquid at some fixed condition, and then physical testing is conducted
to determine or measure any changes in its properties. Usually such a
test is conducted in the absence of stress, although stress-crack
measurements may be made for some polymers. Little attempt is made,
on a regular basis, to actually measure the transport of a liquid
through the membrane as a measure of compatibility. Water, aggressive
liquid reagents, and leachate are all used to challenge the barrier
material. Whether the barrier material is to be used for an FML, pipe
lining, or a bottle, the final compatibility test is always made with
the liquid that is to be contained.
A number of literature sources review polymer v^e,f^iftg at several
technical levels. Characteristics of polymer testing are evident from
the literature. It is not our purpose to develop a theory of testing
here. The reader is referred to these sources for further background
and scientific discussion (Refs. 12, 17-22).
The chemical resistance of polymers is an inherently more complex
matter than that of metals, where the standard expression "mils per
year attack" is clearly measured and the effect understood. The term
"chemically resistant polymer" is necessarily vague, since each word
has degrees of meaning. The strength and functionality of a polymer
material is altered not only by aggressive chemical attack, but also
by time and temperature. Water, frequently termed "the universal
solvent," not only plays a role in accelerating the degrading action,
but can by itself be an aggressor (Refs. 23, 24). In any case, the
purpose of the FML is to prevent the passage of the challenge liquid
or constituents of the liquid into the environment in spite of all
other circumstances. A measure of how well the barrier functions is
based on the chemical compatibility test. The question is:
Poe* the. t&At ade.quate.f4f rr&aAusie. the. Acqitctemen^?
Most tests, as we shall see, measure chemical resistance
indirectly. After exposure to a reagent, some physical property of
the material is measured by mechanical teans. A stress-strain
measurement on the FML is a widely accepted technique for generating
19
-------
chemical resistance data. Stress-strain and dimensional change
measurements are related to polymer structure and behavior.
Although the FML rubbers and elastomers are visco-elastic mate-
rials, creep and fatigue measurements are almost never made. Direct
chemical analysis by techniques such as infrared spectroscopy, chroma-
tography, or mass spectrographic methods is rarely conducted by FML
producers* although polymer producers and research institutions employ
such techniques for polymer characterization. '
5.2 TEST METHODS
The search for information on compatibility test methods included
not only tests strictly intended to determine the chemical resistance
of rubber and plastic membranes such as FMLs, but also allied tests
(e.g., for pipe, packaging, and film). All types of tests that were
relevant to chemical resistance and the transfer of liquids through
membranes were considered and reviewed.
Levels of information sources are categorized as follows:
I. International standards and tests;
II. National standards and tests;
III. Industrial standards and tests;
IV. Project tests; and
V. Academic/literature tests.
The organizations, along with the identification code used in the text
for which tests are reviewed, are listed below:
International Organization for Standardization (ISO)
Geneva, Switzerland
Deutsches Institut fur Normung (DIN)
Berlin, Ge many
British Standards Institution (BSI)
London, England
U.S. Environmental Protection Agency (EPA)
Washington, D. C.
National Sanitation Foundation (NSF)
Ann Arbor, MI
American Society for Testing Materials (ASTM)
Philadelphia, FA
U.S. Military Standards (MIL)
We used the key words in Table 5.1 in our searches. To
adequately conduct the searches for chemical compatibility test
methods, we found this extensive list of topic areas required
consideration.
20
-------
TABLE 5.1. KEY WORDS USED IN LITERATURE SEARCH
(Based on Applied Science and
Technology Index with Additions)
Absorption
Absorption Apparatus
Admix
Adsorption
Asphalt
Asphalt Lining
Chemical Apparatus
Chemical Compatibility
Chemical Plants, Corrosion
Chemical Plants, Environmental Aspects
Chemical Plants, Waste
Chemical Resistance
Chemical Standards
Chemistry Apparatus
Compatibility
Composite Materials
Composite Materials, Testing
Containers, Testing
Containers, Flexible
Containers, Plastic
Corrosion, Testing
Corrosion Research
Corrosion-resisting Materials
Corrosion-resisting Materials, Testing
Diffusion
Diffusivity
Elastomers
Elastometers
Flexible Containers
Flexible Membranes
Flexible Membrane Liners
Geomembrane
Geotextile
Lagoons, Sewage
Landfills
Leachate
Leaching
Mass Transfer
Membranes
Packaging, Permeability
Packaging, Testing
Permeability
Pipe, Testing
Plastic Film
Plastic Film, Permeability
Plastic Lining
Plastic Sheeting
Plastics, Aging
Plastics, Crazing
Plastics, Failure
Plastics, Specifications
Plastics, Strength
Plastics, Stretching
Plastics, Swelling
Plastics, Testing
Plastics, Wear
Plastics, Laminated
Plastics, Laminated, Failure
Plastics Research
Polymers Testing
Roofing
Roofs*
Rubber, Aging .
Rubber, Strength
Rubber, Swelling
Rubber, Testing
Rubber, Artificial, Aging
Rubber, Artificial, Strength
Rubber, Artificial, Swelling
Rubber, Artificial, Testing
Rubber Goods, Testing
Rubber Lining
Rubber Research
Rubber Tanks
Rubberized Fabrics
Solubility
Sorption
Tests
Testing
Testing, Equipment
Testing, Machines
Waste, Disposal
Waste, Products
Waste, Lagoons
21
-------
Of the 27 tests reviewed in Section 5.3, nine deal strictly with
FML/waste testing. Of the nine, two tests, NSF Standard 5A and EPA
Method 9090, are in contention as a standard method. All .other tests
described methods for polymeric film and sheeting in general.
For all the tests in general, the method of exposure consists of
immersion of a test specimen in the challenge liquid, or of exposure
of one side to a reagent. Usually the test is conducted without
straining the sample. None of the tests has been created for field
use, although field-exposed samples obviously can be brought to the
laboratory for measurement. All test methods depend upon specified
reagents, and some include water as the chemical challenge.
Actual challenge chemicals are suggested for final testing, but
no standard waste compositions or leachates have been cpecified for
laboratory screening. The temperature specified is 23°C or service
temperature, but elevated temperatures are specified in several cases.
The duration of the test is quite variable—from hours to months—and,
in some cases, until equilibrium is achieved. Evaluation of compati-
bility is based primarily on weight and dimension change, as well as
upon several mechanical properties. Almost no failure -criteria are
given in the methods. It is left up to the tester to decide what
constitutes a failure or significant alteration in properties. This
evaluation depends upon the investigator's or manufacturer's experi-
ence and is based upon familiarity with the product. *
5.3 COMPARISON OF TEST METHODS
Tables 5.2 to 5.6 compare, in summary fashion, the relevant
features of the test methods pertinent to chemical compatibility
testing. Aside from the details, a similarity is seen among types of
tests. All the tests were developed for compatibility character-
ization in the laboratory.
Following the tables are detailed descriptions of these tests.
They follow in the same order as in Tables 5.2 to 5.6.
Figures 5.1 to 5.13 describe schematically selected tests typical
of available test methods. These figures are useful in judging
quickly the complexity of tests and flow of work involved.
22
-------
TABLE 5.2. INTERNATIONAL STANDAlRDS AND~TESTS~
mi RW/DR SOURCE
KTHM
TEWEMTURE
MRUTIH
FMIWE
CRITERIA
EWIFIKRT •
in m PUSTICS--
EFFECI OF UOUII CHENICM.I
IUIIIIIK;
CKRICM,
MC
73 C
24 HOUR
I KEK
UKEX
(KIWI
mtmttH. ntr
iwr SPECIFIED
Ml KMnEKIT OF
IIVEI IFTER IMKKM
IIKKSIIM FOUMM IT
NTIN.
ISO 1117 VU.CW1IEI
RUIKIIS--«fSISrAI"Cf TO
IIBIIIK
ONE-IIK
OR
SEDVICE
TEW
ra IE tfnmmt
KIWT
HHEnims
ItNSIlE STREKn
EimMTim
NOMHUS
•ME MMTHM KTCMIIIKI ir
CIVEI KICHT SIHll I/«10*.
KDSWIEIIENTS MK HIER
HMERSIDN MD HfTfd IIKIWIW
FOUMTI IT MTIMS.
I!,17
DIN » 521 ROIKI-
KSIS1MCE TO UWItS,
VN>MS, Wl BASES
ONE-SIK EIPOSME
OR
HMERSION
MSTE
SERVICE
TEW
7 MTS, Will
fWIUNIIM
KIWT
IIMENSIMS
HMMESS
aORMTIM
TENSILE STREW™
KTEMIINEI IT
•EIGHT SWILIM1IOK.
l,5,R,f,IO,
II,IJ
OK-8IK flfBSWE
73 C
COUIIINIW
KIONT
•iisiwns TO
FUEl
IIVEI
MMf l« KTERR1KIIY
KIENT STMllUMIOH.
IS Ull CMEHICRl
KESIJiWtt OF n»STICI
IOCIWIK
IWCRSIDN
«MTC
21 C, M4.
KRVIIX TEW
manim
IIKISIM
RfHMMIX
TERStlE ITKKIN
FU1
SMERI
•inn
NMIIM KTFJHIKI IT
KIM SMIIUMTIM.
IS 3I7J NOSES-
CHEKICAL MSISHWtf
ORF.-IIK EIFIHURE
CHFJIICALI
StRVICf
TENP
22,71
7HW
rmni IIREMTN
NRROKIS
ClORMTIW
mt
nva
5,1,11,12
i SEE U6EM »T EW * T
-------
TABLE 5.3. NATIONAL STANDARDS AND TESTS
to
ftSI MD/IK SOUKf
fp» KIMOO ton
NSf SIN»«ftt 34
MM 1513 MSKIMtf I
UMIICS 10 CNEMCN.
MMMIS
KIHOI
OK-Sltf E1POSUM
IMKISIM
HWRSIOII IMKR Sl«»l»
IMttSIM
CHIUEKC lEfffMfWC
MSK U C
MSK »C
nc
WHIMS 21 C
WMriM KASWCKKIS MftUK COmEKIJ
CIIIEIU
M, t», t», KIM KFEttU II
in IMS IIKKSIMS m KM
1ENSIU SIMKTH DOCUKII9
KM
ruKTUK
HMHtSS
EIMMIIM
IMMI KM- KICK! WK UMfSKS IMHSIM *
1,1,7 Mil IIKHSfOM Sl«« Fft'S WIU UM(» SIMt*.
tons KM- tmmva
1,1, U M« Ml KiSHE SIKK1N
!,},« MM1KS KM
MM US
1 MV . KIWI MK
IIKDSIMS ilffl
KCWIIIICM MV
(HOI smiFIH)
E80IMMI I
11,17,11,14
ftSINMM MMKI-V«NI
IIAKSNISSin
M-SIK EINSUM
mn
nc
IM.Itl
Ktwr
sivn
i.i.t
tJII 120 tHMItH KIISIMCt M-SIK EIKSME
» nmiK cunm
MSK
•i sminii
w
IIVH
MNM7I WNfl-EfFECf IMMIM
gr nun
nan
KWItt
Kir
KIWI
IMMIM
itniu SNCMM
iwtwss
KM
titn
12,1)
ME-SIK {ffOSMC
MKMFI INKS
fUL
2X
l.J.I MIS
KIWI
IIVU
I KE UKM M W V IMLf l.t
-------
TABLE 5.4. INDUSTRIAL STANDARDS AND TESTS
TEST mm SOURCE
KTNH
murac
TEIKWHBK
MMTIM
KMWtitRTi
MllWt
CIIHII*
CaMNERTI
EWIPNENT •
SCHLESEl
IHKRSIM
WSTE
70 C
Will KISHt
IIUIUIMIM
in MT HIRIIRM)
NEISRT
HHERSiMS
TENSIU STUENBTH
EUMMTION
itvn imERstm Ens OTTER
KISHT STM1LIIES.
FDILME mnm IIVEH.
).f. STEVERS
IK-1IDE EIWSWE
IMCniM
WSIt
IM C
30 C
71 C
I>2,1,«
KIM
IIKHSim
TENSILE STKMTfl
1EM
ElPMMlin
nOMJLlR
SEM STKR6TH
•ME ME-SIK CmiSURE IS »
IIVEK Pim-TfPE TEST IEVEIOPEI
IT STEVENS. THE IHHERSIIM
1E5T IS M »STH TEST.
11, IJ
satoLt
IIKISIM
nun
we
71 C
;, ». M,
H MT1
KIW?
ItimiMf
TEMILE
TEW
ElMMTlaN
IIVER
(WrtlfIKE IS MH TB
R» «IHOI.
l,l,f,ll,ll,
13
» Sff U8ERI IT m V TMll S.I
-------
TABLE 5.5. PROJECT TESTS
ro
Kit M/« KUKf
mi
lUfEMKM
1*1101
ruuK
EMIMOtl
roue* tin imnu
TUI Kit (Mil)
IMEISIM IfSI INHI)
KSF m pouter
HIMtl
M-IIK iinmi uicMfE n c
IMUCIM
HUM * U«l IIWUII, MUI
MIEN* nun n c
III* MSIE.
MTMM ll» MIK
Eirosutt Minn
•
IHKIM MSH » C
'
IMEISIM MIK M t
MC
iMHin mn M c
II MUM KIM MK KIM II HN IVttlM
II miNI MKMIM ll«tll tIKM It < tUCMII.
KMIlt IIMMII
(IMW7IW
MMKSI
Mill MSMMIM
NKIME KIISIMCf
iHCiric Mum
ASH
WUIIttl
CIIMC1MUI
U7MH . «IMI MK IVM.MIEI IK KMEUII
ICWdNIIMI ,* IIHI VIIKI. '
aECIIICM. CMWCimtT
'
Ml MH IMHMN MK
KKIlE IIKMn (IVfi
IWSIlf Kl
tlMMIIM
MM III
NKIWf KIII1MK
WBAVB MltMyf »^g.
Mm •Livm MNK
1,1,1 MHm IMEMIM ll«l
) nun minus
EIIIKHMI
KM
IEKIU IIMMM
NKIME KlISIMK
S.
1 IHMTICM KIWI * MK
1 Mn IIRUSIM IIKI
IM KM KMI1E IIKMIH
i,M«,n,u Mn KM
21 WPH *KMMtE
tMHn ' KIMI MK
WKMMtt IIVW
ElMMIIM
IEKIU IIKHM
nuiK-itMn
* 11,17,14
II,II
i SEI U6£« M EM OF ItHE 5.i
-------
TABLE 5.6. SELECTED ACADEMIC/LITERATURE TESTS
TEtTM/mnuKt
KTNOI
TfWfMTWt
WMIKM
MllWf
OITHI*
CWMWTJ
KHEflML OCHICM.
MfOtrilM,
CMF1NTEI t MS**,
WIHIM.S PfRFMNMICt
HKIJIM
CHEMICM
n t
», 170 Mfl
KIMt
HNEMIM
HMMESS
»in n MIN ifiBWfioti rurcii
« cvtftv 4 n i Mrs.
IKS OF m n
Ksmrum.
17
FIBII KSlStMCf IF
mum M
III1FJ t
IIKIMIM
MltlCdlS
?t C
?oe
I«OC
HWDttSS
CdtLKlin DF MT»
IIVf»
1,3,1,l», II
NJ
smn CTMIIW IT
CKET MPIUK ttn,
MOKM n AST in
IMEHIM
IMKI IIMIN
CHHICdJ
WIL
FHIUK
UK 10 FMlURt
IIVtH
2,1.1
(KMM
MUUtlM,
(HUM
mmm,
IMHII irun
•T KFIKI
UMMTIM
mm IENSIM
8IVf»
tNMMF. V
KMMH
OF nm.
7.5,1, l
IUVMOMWIMMnM.
uptn ttmm v
EtmifM PIM1ICS
INKRIM
UMXI IIMIN
atmuLt
75 t
•nil
IIIK It FdllUK
IIVEN
Htll 01 CIKSTM1 S1MSS
wni
7,3,1
lUKM
i. inru c«ir*m* u«t, MIHH, KMCCM, IISNEII
7. VICIM. OMUlin IIMKI, UMK ffSSEll, IMIWE COMTMCIIMI
i. mfSNM ammicii <«mifi mssuno
«. nucM
3. FIIIIWI inn, munim m sumn
t. KMMim ecu
7 tiuut
t. nNpfMiuic KM.«m
f. NlONCf
II. mCMMETHI
ii. smss-smi* nmmm
». MWNtn mttnm
II. KM KSItl
H. FWCtWt 1ESKI
13. IMPKI TtSKI
II. TO.lBF.tll
17. FD KIE*
-------
5.3.1 ISO 175 - Plastics - Determination of the Effects
of Liquid Chemical including Water (Ref. 25)
Test Description
This is an immersion test in which at least three precut
specimens are used for each test. It is conducted at 23°C and 70°C.
Samples are conditioned before immersion according to another ISO
standard. The test solution is the liquid to which the material will
be exposed in actual use, or, if this liquid is unavailable, a list of
test liquids is given.
The preferred test durations are: *
a) 24 hours for a short test,
b) one week for a standard test, and
c) 16 weeks for a long-duration test.
During the immersion, the liquids are stirred at least once a
day. If the test lasts longer than seven days, the liquid is replaced
with an equal amount of the original liquid every .seven days.
At the end of an immersion period, the samples are removed,
rinsed with a product that has no effect on them, and blotted dry.
Weight and dimension measurements are made on the samples. They are
then dried at 50°C for 2 hours and the measurements are made again. •
This procedure of making a measurement, drying the samples, and
repeating is also used for the mechanical testing of the samples.
Separate specimens of the sample material are used in each part. No
specific mechanical test types or methods are listed.
This method specifies a method of exposing rubber specimens to
liquid chemicals and is followed by measuring the changes in prop-
erties resulting from such exposure.
Referenced in Test
ISO 62, ISO 291, ISO 3205.
28
-------
ISO 175
MATERIAL
CONDITIONING
IMMERSION
23C
CONTROL
_L
IMMERSION
70 C
| 2am | [ 1 week | }16 week
Drying
Test Test Test Test Test Test
^^^^^^^^^^^^^^
| Drying
Test Test Test Test
Drying
Test
EVALUATIONS
Weight
Dimensions
Mechanical (not specified)
Figure 5.1
29
-------
5.3.2 ISO 1817 - Vulcanized Rubbers - Resistance to Liquids (Ref. 26)
Test Description
This test can be conducted by immersion or -by one-sided exposure
of the specimen. At least three precut specimens are needed for each
.test. The test liquid is preferably the liquid to which the test
material will be exposed in actual use. If this is not available,
several test liquids are suggested.
The time-lapse between vulcanization of the rubber and the
testing should not exceed 3 months whenever possible. The precondi-
tioning of the samples is done according to ISO 471.
The temperature at which the exposure is to take place is not
specified in the standard. However, whenever possible* the tempera-
ture should be equal to, or slightly more severe than, that at which
the rubber will be used.
•
The duration of the test should be established by measuring the
penetration of the test liquid into the rubber. This is accomplished
by monitoring the change in the volume or dimensions with time during
immersion. The test duration should continue well beyond the point of
stabilization of the measured quantity.
The physical properties determined after Immersion are tensile
strength, elongation at break, modulus, and hardness.
The same physical properties of a second set are measured after
drying the immersed samples under a pressure of 20 kPa at 40°C to a
constant mass.
Scope
Evaluates the resistance of vulcanized rubbers to liquids.
Referenced in Test
ISO/R 37, ISO 48, ISO/R 471.
30
-------
5.3.3 DIN 53 521 -Determination of Resistance to Liquids, Vapors.
and Gases (Ref. 27)
Test Description
This test is run either as a one-sided exposure or as an immer-
sion test using at least three precut specimens for each test. The
exposure vessels are not specified in the method other than that they
not allow vapor to escape. The test liquid is preferably the actual
exposure liquid. However, if this is not available* a series of the
test fluids listed can be used. The test temperature should be
slightly higher than the service temperature, but it must be known
that no degradation processes take place at this higher temperature.
The volume of the test fluid is at least 15 tines the volume of the
exposed membrane samples.
The exposure time should be greater than the time required for
the materials to reach equilibrium. Suggested are the following
exposure periods or multiples thereof: 22 hours, 70 hours, or 7 days.
The control is an unexposed sample.
The properties measured include weight, dimensions, volume, hard-
ness, tensile strength, and elongation at break.
Evaluates the resistance of rubbers and elastomers to various
liquids, vapors, and gases.
Referenced in_Test
DIN 50 OU, 51 604 Part 1, 53 502, 53 504, 53 505, 53 519 Part 1,
53 538 Parts 1, 2, 53 598 Part 1.
31
-------
. 1
| 22 Hr
|
I Test I
MATERI/M-
i
IMMERSION
or
ONE-SIDED
70
1
Hr
Test
CONTROL
7D
7x Days
Test | Test
EV/M-UATIONS
Weight
Dimensions
Volune
Hardness
Tensile Strength
Elongation
Figure 5.2
32
-------
5.3.4 DIN 53 532 - Permeability of Elastomer Sheeting to Liquid Fuels
(Ref. 28)
Test Description
For this test, a precut specimen of the elastomer is clamped over
the top of a test vessel which has been filled .with a particular fuel.
The device is allowed to equilibrate for 24 hours In the upright posi-
tion. The device is then weighed and Inverted to begin the exposure
period. Weight measurements are taken every seven days until the
weight loss becomes a constant for four, successive measurements. The
permeability can then be calculated by a formula presented in the
method. Three specimens are required for each test.
This method is used to determine comparable permeabilities of
materials for a given fuel.
Referenced in Test
DIN 1301, 50 014, 53 521.
33
-------
5.3.5 BS 4618 - Chemical Resistance of Plastics to Liquids (Ref. 29)
Test Description
This test can be run either as an immersion or as a one-sided
exposure. At least two precut specimens are required for each test.
.As a first phase, the plastic materials are exposed to a variety of
the chemicals listed. Materials that show good resistance to
chemicals of interest are selected for exposure testing to the actual
waste liquid.
The exposure vessels for this test are not specified. Only one
type of material is allowed per exposure vessel. .The temperatures for
the exposures are 23°C and the manufacturer's maximum recommended
service temperature.
The exposure is terminated when only small changes occur in the
material with time. If the material is still changing significantly
after 16 weeks, it should be classified as non-resistant. The con-
trols for this method are samples exposed to the atmosphere for the
duration of the immersions.
The properties measured are dimensions, appearance, tensile,
flexural, and shear or impact strength as appropriate for the mate-
rial.
Scope
Evaluates the resistance of plastics to liquid chemicals.
Referenced in Test
ISO/R 175 and BS 3502, 3978, 148, 1911, 2782.
34
-------
MATERIAL
IMMERSION
or
ONE-SIDED
CONTROL
Exposure to
Suggested Chemicals
23C
No Change
With Time
Test
Max
RccommenocQ
Temp
No Change
with Time
Test
Repeat With
Actual Waste
EVALUATIONS
Dimensions
Appearance
Tensile Strength
Rex
Shear
Impact
Figure 5.3
35
-------
5.3.6 BS 5173 - Hoses - Chemical Resistance Tests (Ref. 30)
lest Description
This test is conducted by bending a length of tubing into the
shape of a large U and filling it with the actual exposure liquid.
The ends are then capped and the hose is held in the U position for
the exposure period. The duration of the exposure period is chosen
from the following: 22 hours, 70 hours, 7 days, or multiples of 7
days. After exposure, the liquid is removed and inspected for changes
in color or the presence of any sediment. The lining of the hose is
then inspected and physical tests for tensile strength, elongation,
and hardness, and such, are conducted.
The test temperature is selected from a list presented in the
method and should be related to the actual service conditions.
This test specifies methods of testing hoses for resistance to
liquid chemicals.
Referenced in Test
BS 903 Part A16.
36
-------
5.3.7 EPA Method 9090 - Compatibility Test for Wastes
and Membrane Liners (Ref. 31)
(A Proposed Standard).
Test Description
' This test method calls for a one-side exposure. Jigs provide a
method of holding slabs of sheeting in tanks such that only the
surface of the liner material that would face the waste in actual use
contacts the sample of waste fluid.
The exposure tank is equipped with a means of maintaining the
solution at a temperature of 50 ±2°C and for preventing evaporation of
the solution. The waste liquid is stirred continuously.
Samples of the liner materials are removed at 30, 60, 90, and 120
-days of exposure, cut out, and tested for tear and puncture resis-
tance, elongation at break, tensile strength, and hardness. Three
specimens are required for each test. Changes in weight and dimen-
sions are also measured. All of these measurements are compared to
those of unexposed samples.
Scope
* '.*|iJ!M4feHt«* -
Determination of the effects of liquid wastes on liner materials.
Referenced in Test
FTMS 101B, Method 2065—Tensile and Tear Tests (Table 5.7).
NOTE: Since completion of this study, a revised Method 9090 has
been issued by the EPA which includes testing at both room
temperature and 50°C. By immersion, both sides of the liner
material are now exposed to the chemical environment, although
the option remains to expose one side in specific cases. Other
features of the revised test are unchanged.
The revised Method 9090 has been proposed for incorporation into
the EPA publication "Test Methods for Evaluating Solid Waste"
(SW-846), which will become part of the revised RCRA Subtitle C
regulations. (See Federal Register, Vol. 49, No. 191, Monday,
October 1, 1984, p 38786.)
37
-------
TABLE 5.7. TENSILE AND TEAR TESTING PROTOCOLS
U*
00
Property to be Teated
Tenalle Propertlea
Method
Type of Specimen
Speed of Teat
Flexible
XL
ASTM DA 12
Dumbbell
20 ipm
Type
Membrane Llnera without
TP
ASTM D638
Dumbbell
20 ipm
of Compound and Construction*
Fabric Reinforcement
CX
ASTM D638
Dumbbell
2 1pm
Fabric-reinforced
Flexible Membrane Llnera
FR
ASTM D751, Mtd B (modified1*)
1 in. x 5 in. atrip and 2 in.
jaw aeparation
12 ipm
Values to be Reported Tenalle strength, pal
Elongation at break, X
Tensile strength .set after
break, Z
Streaa at 100, 200, and
3001 elongation, pal
Tenaile strength, pal
Elongation at break, X
Tenaile strength set after
break, Z
Streaa at 100, 200, and
300Z elongation, pal
Tenaile strength at yield, pal
Elongation at yield, X
Tenaile atrength at break, pal
Elongation at break, X
Tenalle strength aet after
break, Z
Stress at 100, 200, and
300Z elongation, pal
Tensile atrength at fabric break,
ppl
Elongation at fabric break, X
Tenaile atrength at ultimate
break, ppl
Elongation at ultimate break, X
Tensile atrength aet after break,
X
Streaa at 100, 200, and 300Z
elongation, ppl
Tear Resistance
Method
Type of Specimen
Speed of Teat
ASTM 0624
Die C
20 ipm
;
ASTM 01004 (modified0)
Dial"
: 20 ipm
1 t
ASTM D1004
Die C*
* 1pm
(d)
*XL * croaslinkad or Vulcanized; TP » thermoplastic; CX - dyetallinef FR • fabric-reinforced.
Specimen • 1 in. x 3 In. atrip; initial jaw aeparation - 2 In.
cCroaehead apeed - 20 ipm.
No tear realatance la recommended for fabric-reinforced sheetings in the Immersion atudy.
*I)le C from ASTM D624.
Source: EPA Method 9090 (Ref. 31).
-------
METHOD 9090
1
30 Day (
1 Test|
t
One-Sioed
Closure
50 C
i
>0 Day 9
[Test I
MATERIAL
1
I
ODay 121
I
LwJ L
h
I
Control
3 Day
rest |
EVALUATIONS
Weight
Dimensions
Tear Strength
Tensile Strength
Puncture Resistance
Elongation
Hardness
Figure 5.4
39
-------
5.3.8 NSF Standard 54 Flexible Membrane Liners (Ref. 32)
Test Description
Precut samples are completely " immersed in the test fluid.
Specific immersion equipment is not specified. Two test temperatures
are suggested: room temperature (23°C) and 50°C. The method suggests
that if the actual service temperature is higher than 50°C, that
temperature should be used.
There are short-term and long-term tests suggested using this
method. The short-term test calls for samples to be removed after 1,
3, and 7 days. The long-term test calls for samples to be removed
after 1. 7, and 14 days, and 1, 2, and 4 months.
After exposure, the samples are examined for changes in weight,
dimensions, and appearance. The method also calls for a gentle
solvent rinse with acetone or other suitable solvent prior to exami-
nation. Samples are then tested for mechanical properties such as
tensile strength, tear, elongation, and modulus (see Table 5.8).
Also addressed is the effect of strain on the materials during
the immersion. Samples are shaped into a loop, immersed for 7 days or
4 months, and then removed and inspected visually for deterioration.
This standard deals with providing a uniform method of specifying
and testing of FMLs. Only Appendix D of NSF Standard 54 deals with
the estimation of performance in chemical environments and is reviewed
here.
Referenced in Test
See Table 5.8.
40
-------
TABLE 5.8. TEST METHODS
Crosslinked Elastomers Unsupported - ASTM D412 (Method A)
• Breaking strength, pounds/inch width
• Elongation at break, percent
• Modulus at 100 percent elongation
Thermoplastics - Unsupported
Materials without a yield point - ASTM D882
• Breaking strength, pounds /inch width
• Elongation at break point, percent
• Modulus at 100 percent elongation, pounds /inch width
t
Materials with a yield point - ASTM D683
• Breaking strength at yield and break, pounds/inch width
• Elongation at yield and break, percent
• Modulus of elasticity, pounds/inch width
• Tear strength, unsupported FML - ASTM D1004
Supported Flexible Membrane Liner
Supported finished FML materials - ASTM D751
• Breaking strength, grab method, pounds or strip method,
pounds /inch width
Ply Adhesion, All-supported FML - ASTM D413, Machine Method, Strip
Specimen, Type A, 180° peel, pounds/inch width
41
-------
MATER1/H-1
1
>cccpr>
JCL<
COhT
FROL
1
STRfci
Immersion
23C
Immersion
50 C
JL
I
10
1
I short term | short term
3D
1
7D
1
ID
30
1
TO
OR
OR
OR
OR
10
1
1 M
long
term
70
2M
, — i —
14 D
I
4M
long
._ L_
ID
7
1
1 M
2
term
D
M
1
14 D
1
ft M
1
ID
I
1M
long term ^
7[
)
i
j 140
1
2M
4 M
long
1
ID
I
1M
7
2
term
D
!
14 D
I
M
4 M
EVALUATIONS
weignt
Elongation
Tensile Strength
Tear Resistance
Modulus
Figure 5.5
42
-------
5.3.9 ASTM D543 (78) - Resistance of Plastics to Chemical Reagents
(Ref. 33)
Test Description
Precut test specimens, at least three replicates per type test,
are immersed in a chemical liquid at 23°C for 7 days. Water is an
optional liquid. For other than room temperature, 50*C and 70°C are
suggested. Other immersion times may be used (suggested are 1 and 3
days and increments of 4 weeks). Changes in visual appearance,
weight, and dimension are determined. Changes in tensile properties
(no methods specified) are determined as well. Fifty standard
reagents are specified.
This test is suitable for testing sheet polymeric materials for
resistance to chemical reagents. Reported are changes in weight,
dimension, appearance, and strength times. Provision is made for
various exposure times and exposures at elevated temperatures.
This is a laboratory test and may not be related to real condi-
tions. Choices of reagents, temperatures, times, and measured prop-
erties are arbitrary. The test is the basis of standardized compara-
tive testing. No criteria for failure or serviceability are given.
Referenced in Test
ASTM D618, D833, D1898.
-------
ASTMD5A3
1
irsiort
! r?
MATERIAL
CONTROL
t
1
Imme]
en
7 Days
7 Days
EVALUATIONS
Weight
Dimensions
Mechanical (not specified)
Figure 5.6
44
-------
5.3.10 ASTM D814 - Rubber Property - Vapor Transmission
of Volatile Liquids (Ref. 34)
Test Description
For this test* a disk of rubber material is clamped over the
mouth of a jar which contains the test liquid/ The jar is weighed and
inverted and then placed in a suitable rack and allowed to stand for
24 hours. The jar is then reweighed and returned to the rack. The
Jar is reweighed again after 120 hours and 192 hours from the initial
inversion. The vapor transmission rate is calculated from any loss in
weight. At least three specimens are required for this test. This
test is run at room temperature.
This method is designed to measure the relative difference in
vapor transmission rates of various rubbers.
Referenced in Test
ASTM D3767.
i—
45
-------
5.3.11 ASTM G20 - Chemical Resistance of Pipeline Coatings (Ref. 35)
Test Description
This is an inanersion test designed for pipe coatings. The
immersion fluid should contain reagents anticipated in actual service.
The immersions are carried out in glass jars with pipe sections capped
at both ends as the test samples. The length of the immersions are 6,
12, and 18 months. The temperatures of the immersions are not speci-
fied in the method. The properties to* be measured before and after
exposure are not specified.
The test evaluates the resistance of exterior pipe-coating
materials to various reagents.
Referenced in Test
ASTM G8, G17, D543.
46
-------
MATERIAL
J_
Immersion
23C
CONTROL
EVALUATIONS
Not Specified
Figure 5.7
47
-------
5.3.12 ASTM DA 71 - Rubber Property - Effect of Liquid (Ref. 36)
Test Description
For this ASTM test, precut test specimens are completely immersed
in the test fluid—three specimens for each test. The test fluid is
preferably the actual waste liquid, but if this is unavailable, alter-
nate fluids selected from a list can be used. A series of different
test temperatures may be selected from tables found in the method
description. The temperature used for the exposure should be the one
that comes closest to the actual service temperature. Recommended
immersion times are 22, 46, 70, 166, and 670 hours.
This method is designed to yield comparative data on which to
Judge,the effect of liquids on rubber materials.
Referenced in Test
ASTM D412, D1193, D1415, D2240, D3182, D3183.
48
-------
MATERIAL
I
Immersion
(selected temps)
CONTROL
166 H
Test
670 H
Test Test Test Test
EVALUATIONS
Weight
Dimensions
Tensile Strength
Elongation
Hardness
Figure 5.8
49
-------
5.3.13 MIL-T-6396D Aircraft Tanks - Fuel. Oil, Water-alcohol,
Coolant (Ref. 37)
Test Description
Samples of the tank, inner liner ply and outer ply, are subjected
to relative humidity of 95Z at a temperature of 160°F for 30 days.
Visual inspection of samples for corrosion, cracking, warping, or
delamination is conducted, and measurements of tensile strength,
'elongation, and hardness are taken. Maximum allowable changes in
these properties are listed.
Permeability of the tank materials is measured by affixing a
sample of the tank material to the top of a half-filled cup of fuel.
This device is weighed and inverted and then weighed again after 3, 5,
and 8 days. The diffusion rate is calculated from the weight measure-
ments made on the fifth and eighth days.
This document covers many phases of fuel tank specification. The
two sections described here are only a small part of the document.
50
-------
5.3.14 Schlegel Test for HDPE (Ref. 38)
Test Description
This is an immersion test that is conducted at 70°C. No special
equipment is required. A sample of the waste fluid is used as the
test reagent. Specimens are precut.
*
Initial measurements of weight and dimensions are made, and then
the samples are immersed in the waste fluid for a total of 28 days.
Every 7 days the samples are removed, wiped dry, and weighed. After
28 days, if the sample weights have stabilized, the immersions are
discontinued and property testing is begun. If the weights have not
stabilized, the immersions are continued until the weights become
constant.
When the immersions are concluded, tensile strength and elonga-
tion measurements are made on the exposed samples and compared to
measurements made on unexposed liner samples.
A test specimen is determined to have passed the test if:
a. the weight change is not greater than ±32,
b. the change in tensile properties is no greater than
±102, and
c. the liner seams are not significantly weaker than
the liner sections.
Determines chemical resistance.
Referenced in Test
ASTM D618, D638.
51
-------
MATERIAL
Immersion
70 C
CONTROL
Weight Measurement
Every Seven Days
28 Days or until
Stabilization
EVALUATIONS
weight
Dimensions
Tensile Strength
Elongation
Figure 5.9
52
-------
5.3.15 J.P. Stevens Test (Ref. 39)'
Test Description
The finished lining is reinforced with polyester. To measure
change in physical properties and percent weight, unsupported CSPE is
laboratory-milled to 0.015 inch from which test specimens are taken.
Test specimens are immersed for up to four months in the actual waste
liquid at 23°C and 50°C. Physical property changes are compared to
the original. The percent change by weight is conducted at 23°C and
50°C, and results are plotted to establish rate of absorption to
equilibrium.
A closed cell ponding test allows the waste liquid to- be exposed
to one side of the finished reinforced lining at elevated temperatures
up to 160°F. A glass cover is sealed over the waste liquid to prevent
evaporation. The test allows for natural phase separation of the
waste.
An open air ponding test holds up to 2 inches of the waste liquid
which, under sunlamps, produces a surface temperature of 160°F and an
effluent temperature of 135°F. The waste is allowed to evaporate
leaving only the solids. The - lining can be resaturated with more
waste. Physical properties and seam strength tests can be* made upon
completion of the test.
Evaluation of lining material in actual waste liquid.
Referenced in Test
ASTM D412, D1004, D471.
53
-------
5.3.16 Gundle Test (Ref. 40)
Test Description
This is an immersion test conducted at 23°C and 50°C. Precut
samples are prepared for tensile and shear testing, according to ASTH
D638. Specimens are also prepared as Ix4-in. strips to be used for
visual inspection, weight measurement, and dimensional change deter-
mination .
*,
Samples are removed from liquid contact after 7, 30. 60, and 90
days for evaluation. Strength testing is done at each time interval.
Weight and dimension measurements are conducted on the strips which
are then returned to the solutions.
The test solution for this evaluation is the supplied waste
fluid.
This test evaluates the liner material by immersion in waste
solution.
Referenced in Test
ASTM D543, D638.
54
-------
5.3.17 Simulation Test (Ha*o) (Refs. 9, 41)
Test Description
Exposure unit: a 2-foot diameter steel pipe, 10 feet in height,
is placed on an epoxy-coated concrete base and lined with poly-
ethylene. The liner is sealed into the base with epoxy. A layer of
sand is then placed on top of the liner. Approximately 1 cubic yard
of ground refuse is compacted above the sand to yield a density of
1240 pounds per cubic yard at 30 percent water content. The refuse is
covered with 2 feet of soil and 4 inches of crushed rock. One cell
for each liner for each time period is required.
Tap water is added at the rate of 25 inches per year. Leachate
is maintained at a 1-foot head above the liner by continually draining
the pipe just above the liner.
In addition, specimens of the liner are also buried in the sand
above the primary liner and thus are totally immersed.
When the samples are removed, they are subjected to a range of
physical tests normally performed on rubber and plastic materials.
This method is suitable for exposing any type of liner materials-
to simulated municipal solid wastes.
55
-------
5.3.18 Pouch Test (Haxo) (Refs. 9, 41)
Test Description
A small pouch is made with the liner material. The pouch is
filled with the waste material or any test fluid, and then sealed and
immersed in de-ionized water. The permeability of the membranes to
water and to pollutants is determined by observing the change in
weight of the bags and the measurements of 'the pH and electrical
conductivity of the de-ionized water. Because of osmosis, water
should enter the pouch, and ions and dissolved constituents should
leave the bag.
Scope
This test is designed to evaluate the permeabilities of the liner
materials to liquid wastes and water.
56
-------
5.3.19 Tub Test (Haxo) (Ref. 9)
Test Description
Plywood tubs with sides sloping outward at a 1:2 slope are con-
structed. The dimensions are 14x9 inches at the base and 25x20 inches
at the top, creating a depth of approximately >11 inches.
Liner specimens are draped over the tubs and folded to fit the
inside contours of the tubs. Excess material is allowed to hang
freely over the edges of the tubs. The tubs are then filled about
three quarters full with wastes. The liquid level is allowed to
fluctuate about 4 inches.
The tubs are kept outdoors during the exposure period. Visual
inspections of the liner and the liquid level are conducted at regular
intervals. The tubs are .covered during rainy weather. The tubs are
also located such that half of them are in the sun and half are in the
shade.
After exposure the liners are tested for a variety of physical
properties.
This test exposes the liner to conditions Chat simulate actual
conditions.
57
-------
5.3.20 Immersion Test (Haxo) (Refs. 9, 41)
Test Description
Samples of liner materials are immersed in a tank containing the
waste mixture. If the mixture is expected to separate, samples should
be hung at different levels. After exposure, the samples are removed,
cut, and tested for changes in weight, dimensions, tensile strength,
puncture resistance, tear resistance, and elongation; one sample for
each immersion time or exposure condition is required.
Scope
To assess the compatibility of liner materials with specific
wastes.
Referenced in Test
ASTM D297, D412, D624, D638, D1004, D2240, D3421.
FTMS 10IB, Method 2065, Puncture Resistance and Elongation Test
(1/8-inch Radius Probe Method) .
Matrecon Test Method 1, Procedure for Determination of Volatiles
on Unexposed Membrane Liner Materials
Matrecon Test Method 2, Procedure for Determination of the
Extractable Content of Unexposed Membrane Lining Materials
58
-------
5.3.21 NSF's FML Project (Ref. 42)
Test Description
For this NSF project, short-term screening tests and long-term
exposure tests are conducted. The short-term, screening consists of a
7-day immersion in various organic compounds at three concentration
levels. The concentration level that shows a noticeable effect on the
liner material without destroying it is used as the highest concen-
tration for the long-term testing. Two dilutions of that concentra-
tion level are also used. Distilled water serves as the zero concen-
tration for both sets of tests. The liner materials are evaluated in
the short-term tests by appearance, weight, and dimensional changes.
These tests are run only at room temperature.
The long-term exposure test is run as an immersion test. The two
temperatures used are 50°C and room temperature (23°C). Immersed
samples are removed from the exposure tanks for testing after 1, 7,
14, 28, and 56 days, and after 24 months. The properties measured
include weight, dimensions, tensile strength, and tear strength.
Changes in appearance are noted. Properties are measured according to
ASTM standards wherever possible. Stirring of the solutions .is not
specified. Fifteen precut samples per material, exposure period, and
temperature gradient are required.
The test evaluates the resistance of several commonly used liner
materials to specific chemicals at several conditions.
Referenced in Test
ASTM D1593, D751, D882, D1004, D412, D624, D638.
59
-------
MATERIAL
I
Level 1
. 1
Test
Short Term
Immersion
23C
.<
1
Level 2
Test
Level 3
1
Test
CONTROL
•-
1
Long Term
1
Immersion
23C
i
|
ID
7D
\
IftD
1 1
16O
560
24 M
i
immersion
5QC
1 .
1 1 1
ID
7D
14 D
1 1
16 b
56D
24 M
EVW-UATIONS
weight
Dimensions
/Appearance
gVALUATIONS
Weight
Dimensions
Tensile Strength
Tear Resistance
/appearance
Figure 5.10
60
-------
5.3.22 Harwell Assessment of Two EDPE Landfill Liners
by Application of an Accelerated Test (Ref. 43)
Test Description
The exposure tanks for this test are stainless-steel pressure
vessels 0.35 meter in diameter and 0.76 meter high. The temperature
in the vessels is maintained at AO'C (representing the upper limit of
temperature encountered in an active landfill site in the U.K.). The
pressure in the vessel is maintained at 20 psi with nitrogen which
prevents oxidation of the leachate.
The composition of the leachate was designed to represent a
particularly aggressive version of that from domestic refuse. The
composition of the leachate "used is given in the source.
The liner samples are attached to the roo'f of the vessel above
the level of the leachate.. To the submerged end of the samples are
attached weights (276 g) to maintain the material tinder tension
throughout the test.
After A months, the liner samples are removed and evaluated for
changes in appearance, weight, elongation, tensile strength, failure
stress, load-extension behavior, and hardness.
This test evaluates liner materials against simulated landfill
leachate under accelerated conditions.
61
-------
HARWELL
[MATERIAL
Immersion
40 C 20psl
1
CONTROL
[ A MonUis|
1
Test
EVWJJATIONS
weight
Elongation
Appearance
TensUe Strength
Tear Resistance
Failure Stress
Load Extension
Hardness
Figure 5.11
62
-------
5.3.23 Sequential Chemical Absorption Techniques for
Evaluating Elastomers (Ref. 44)
Test Description
This test is a modification of ASTM D471. Modifications include:
(1) use of a thinner sheet stock for testing to accelerate the
approach to equilibrium, and (2) increase in exposure periods from one
long period to at least four shorter ones to permit extrapolation of
the data to infinite time. The exposures are complete immersions and
the properties measured are weight, dimensions, and visual observa-
tions. Hardness measurements are made only at the end of the final
period. The test period may vary from 4 to 10 days with a total
elapsed time of 120 days.
With an integration of Fick's second law of diffusion and the
data obtained from the testing, the weight gain at infinite time and
the diffusion coefficient for the material are calculated. If this
weight gain is greater than 102, the material is eliminated from
further testing.
Desorption of the successful materials, ones with less than 102
weight gain, is then conducted in open jars at room temperature until
the weight stabilizes. Any material that shows a loss in weight is-
considered unacceptable since it indicates leaching of the elastomer.
A preferred material is one that passes both of these tests and
does not lose more than 10 durometer points (hardness) over the
duration of the testing.
Evaluates chemical resistance of elastomers by determining
maximum absorption values and diffusion and permeation properties.
Referenced in Test
ASTM D471.
63
-------
5.3.24 Guide to Fluid Resistance of Rubber and Elastomers (Ref. 45)
Test Description
The test method described is an immersion test in which the
specimens are exposed in 4-ounce jars. The exposures are carried out
at three temperatures: 26°C, 70°C, and 100°C. The materials are
tested against water, transformer oil, ASTM oil No. 3, and a chlori-
nated, aromatic dielectric fluid. The properties measured include
hardness and volume changes. Measurements are taken after 1, 7, 14,
and 28 days. These tests are conducted with natural rubber and 17
elastomers.
Evaluates chemical resistance of rubbers and elastomers
(compilation of hardness and volume change data for 18 materials
versus 4 fluids).
Referenced in Test
ASTM D471.
64
-------
5.3.25 Environmental Stress-cracking by Creep Rupture Tests (Ref. 46)
Test Description
In this test, the environmental stress-crack resistance is
measured in terms of the loss of strength of the material. The test
specimen is mounted by clamping one end to the bottom of a cylinder
and the other to a lever arm with weights on the arm to create the
tension on the sample. The cylinder is filled with a chemical, and
the time to rupture the specimen is measured as a function of the
applied stress. The test can also be run at elevated temperatures.
This method measures the stress-crack resistance of plastics in
chemical environments.
Referenced in Test
ASTM D1693, D2990.
65
-------
5.3.26 Chemical Stress Relaxation Test (Ref. 47)
Test Description
In this test, materials are exposed to liquid chemicals while
under stressed conditions. The material is held under tension by
fixing one end to the bottom of the exposure tank and the other to a
spring. A selected load is then put on the spring. The chemical is
added to the tank and held at a constant temperature (room tempera-
ture* or 40°C) for the duration of the test. The elongation of the
test specimen is held constant during the test, while the amount of
spring tension required to hold it there is recorded with time. A
stress ratio is calculated and plotted against time to develop stress
relaxation curves for the material.
The use of stress-relaxation for evaluating the chemical resis-
tance of plastics is described.
66
-------
CHEMICAL-!
AXATION
MATERIAL
. ,
immersion
under
40
Stress
C
EVALUATIONS
Elongation.
Spring Tension
Figure 5.12
67
-------
5.3.27 A New Method for Determining Environmental Stress-crack
Resistance of Ethylene-based Plastics (Ref. 48)
Test Description ' .
In this test, materials are bent around a metallic form having a
specified radius of curvature. A constant load is then applied to the
material by attaching weights to a cord that is attached to the
material over a series of pulleys. The material is held in this
manner in a tank containing the stress-cracking agent, a 102 solution
of nonylphenoxy poly(ethyleneoxy)ethanol in distilled water. The
temperature of the test is 75°C, the applied stress is 5 MPa. Nominal
sample thickness is 0.100 to 0.125 cm. The test is terminated when
the material fails.
This method is designed for the determination of environmental
stress-crack resistance of polyethylene-based plastics.
Referenced in Test
ASTM D1693, D2552.
68
-------
FNVIRONk^NTAl STR
OF ETHYLFKE PLASTICS
Immersion
Under Stress
75C
Time Until
Failure
EVALUATIONS
Time under stress until failure
Appearance
Figure 5.13
69
-------
5.4 TEST STATE-OF-THE-ART
A general feature of the tests described in the previous section
is commonality of approach. This is evidenced by the cross-
referencing of key tests (e.g., ASTM D543, ASTM 471, ISO 175, ISO
1817, DIN 53 521, BS 4618). The approach appears to.be based on
assimilating test methods for rubber sheet and plastic sheet into a
test useful for FMLs. It is worth noting that a "caveat" is generally
found in each method, warning that the test may not correspond with
the service condition and that data are only comparative in nature.
Absolute values or criteria for compatibility are not established in
the tests.
*
At the present time, two specific test methods for evaluating FML
performance in a chemical environment have evolved—HSF Standard Mo.
54 and EPA Method 9090. The latter was designed specifically as a
compatibility test for membrane liners in the presence of waste. In
the NSF standard, chemical compatibility testing is described in
Appendix D of the document which deals with other aspects of FML
specifications. The NSF method is a voluntary approach to industry
standardization; the EFA method may be promulgated as a national
standard having regulatory authority. The NSF test is primarily
short-term, although provision is made for longer testing.
Both tests rely on measurement of similar physical property
changes. Criteria for failure are not specified by the NSF test, nor
the EFA test, although the EFA test refers to R<^ jjujjjince documents
for evaluation of data. The NSF document deals with stress-cracking
phenomena in a separate test; the EPA test does not at all. Both
employ similar test temperatures (23°C and 50°C). Importantly, in
Method 9090 samples are subjected to one-side exposure; in NSF 54,
individual test specimens are immersed in a reagent. Both recommend
FML contact with actual waste liquid or leachate.
Other FML industry test methods depend primarily upon immersion
in fluid, although one-side contact in a simulated ponding arrangement
(heated dish or tub) is sometimes used. Attempts are made to simulate
real experience, but the pro's and con's of the exposure methods are
still being debated. Again, physical and mechanical features are
monitored for change. Information on industry test results is scarce
because results tend to be proprietary. Industry does retain its own
concept as to what constitutes failure in products. Tests are static
in nature and single property measurements (e.g., tensile strength,
elongation, hardness, and tear strength) suffice for characterization.
Manufacturers and users of polyethylene products are interested
in stress-cracking. For these products, this property is tested by
stressing a test specimen in a solution of a surfactant. Current work
at the Polymer Science and Standards Division, National Bureau of
Standards, is being devoted to the investigation of stress-cracking of
70
-------
ethylene-based plastics in the presence of liquid stress-cracking
agents (Ref. 48). A review of stress-crack testing is given by Titow
(Ref. 49). Methods discussed are free-bend methods, imposed-curvature
methods, three-point bending, plain-strip-specimen, holed-strip-
specimen, biaxial methods and others. Choices in stress-crack testing
appear just as complex as those in the physipal tests described for
compatibility.
EPA, NSF, or industry tests have not included permeation measure-
ment in compatibility testing, although ouch research has been and is
underway which should lead to the measurement of this property. If
the waste barrier is to be maintained, then passage (via A permeation
diffusion mechanism) of liquid through the membrane in the absence of
holes should not be permitted.
In summary, the tests reviewed exhibit the following character-
istic features:
Test by immersion or one-side exposure;
Test without stress* except for the polyethylene-type
plastics, which are a special case;
Test at ambient temperature and some elevated temperature;
Test with varying time (short to long), or to equilibrium;
Test in laboratory;
Test with reagents or waste; ''•****--IK****- -,
Measurement of mechanical properties and evaluation of
appearance as the preferred indicators of compatibility.
No one test satisfies all needs for a chemical compatibility
test, and test protocols and experimental details are subjects for
discussion and re-evaluation.
5.5 CONSENSUS MEETING
As part of the need to elucidate and understand compatibility
test methods and FML requirements, a meeting with experts in FML
technology and applications was held at Arthur D. Little, Inc.,
Cambridge, Massachusetts, in January 1984. In attendance were several
manufacturers' representatives, an independent FML researcher, EPA
representatives, and members of the Arthur D. Little staff. This
meeting provided an opportunity to discuss the current test method-
ology and recommendations for improvements in tests for FML compati-
bility. The discussions identified areas of concern, issues, and
means for resolution. This meeting was most useful in bringing to
light practical aspects of testing not dealt with in the published
test methods discussed in prior sections. Because they provide
valuable insight, the Minutes of that meeting are reproduced in
Section 5.6.
71
-------
5.6 MINUTES OF MEETING ON COMPATIBILITY TEST METHODS
AND FML REQUIREMENTS
5.6.1 'Exposure Conditions
Immersion vs. One-side Exposure
Industry representatives were in favor of immersion testing, but
split on the question of whether or not supported materials should be
tested with or without the scrim. One argued that if you want to
measure the change in strength of the liner, you should leave the
scrim in place. Others suggested that to evaluate a change in the
material by measuring strength, scrim should not be Included since its
strength overshadows any change in the material. Ply adhesion between
scrim and the barrier material is a concern. Everyone agreed that if
scrim were included, the edges should be sealed to prevent wicking of
the waste into the liner.
One EPA representative was in favor of one-side exposures since
this would accommodate composite liner materials (multi-layered) where
chemical resistance was not required for both sides of the liner.
Several people responded that composite liners were not practical for
the near future, .because of the technical problems associated .with
them.
In testing, the rate of chemical attack would be much faster in
an Immersion test; therefore, any adverse effect*^HOuld J>e seen more
clearly in a shorter exposure time.
Duration ..
Most parties agreed that a three-level testing protocol was a
sound approach. The three levels are outlined below:
Waste
Duration Temperature Concentration
30 days Room temperature (23°C) Actual and 10
and 50°C times by
evaporation
or spiking
Intermediate Four months Room temperature (23*C) Actual and 10
and 50°C times by
evaporation
or spiking
Long-term More than Actual service Actual
four months temperature
72
-------
The short-term test was considered a good way initially to screen
materials for further testing. Samples should be removed after 1, 7,
14, and 30 days for evaluation.
The 4-month, intermediate exposure did not receive much
criticism. Everyone recognized the need for a test with a significant
exposure period to demonstrate the resistance of the liner material.
Removal of samples after 7, 14, 30. 60, 90, and 120 days for testing
was suggested, along with replacing of the waste fluid every 30 days.
Long-term data are important and are urgently needed, both from
laboratory and field tests. 'A field lifetiae ~t*st was strongly
suggested as a means of monitoring the liner during its actual service
life. Attaching coupons of the liner material to a frame and placing
the frame on the bottom of the pond was mentioned as one method of
conducting this test. Samples could then be removed for testing after
several years without cutting out a piece of the liner itself.
Temperature
The use of higher temperature for accelerating the test assumes
that any degradation process occurring at the higher temperature is
the came as those encountered at the lower temperature. One industry
.representative objected to the use of elevated fi||mperatures for two
reasons: (1) the temperature may kill the active »icro-organisms that
can attack an FML in the pond in actual use; and (2) the loss of
volatile solvents in testing would have to be addressed. Another
practical problem mentioned was that it may be too dangerous to expose
the solvents to the higher temperature. It was agreed, however, that
higher temperatures would accelerate chemical degradation taking place
as a result of the exposure to the waste.
Concentration
Everyone believed that the liner material should be tested
against the actual waste mixture. Exposure to the pure chemical was
rejected, since it does not simulate actual conditions where concen-
trations are usually very low. Exposure to 10 times the expected
actual concentration, on the other hand, was considered a good way to
simulate a worst case situation that may develop In a pond. However,
it was recognized that concentration of a received waste for the test
would not always be feasible.
Phase Separation
If phase separation of the chemical in the waste mixture is
expected to occur, samples of the liner should be placed at several
levels in the exposure tank to intercept each chemical. All of these
samples should be evaluated after the exposure period.
73
-------
5.6.2 Test Methods
All agreed that just one set of tests for all types of liner
materials would not be appropriate. The tests must be proper for the
type of material being tested. Three major classifications of mate-
rials were suggested. Below, commonly used liner materials are
classified and typical tests suggested.
b
Classification Type
1. Thermoplastic
2. Crosslinked *
3. Semi-crystalline
Stress-
Type AWeight Tear* Tensile Elong. Modulus crack
X
X
X
X
X
X
X
X
Material
PVC
HDPE/LDPE
CPE
CSPE (CSM)
EPDM
ECO
Neoprene (CR)
Butyl (IIR)
*Not with fabric reinforcement
1
3
1
1*2
2
2
2
2
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
In addition, it was suggested that dimensions and hardness also
be checked on all materials since these properties are easily
measured.
Static vs. Dynamic
After some discussion, it was agreed that results produced by
dynamic testing would be interesting. However, this type of testing
of materials is not understood well enough in relation to compati-
bility at this time. Static testing, on the other hand, was
considered adequate to measure changes in the materials caused by the
exposures. It was suggested that a research study be conducted to
determine the usefulness of dynamic testing (e.g., rheology, creep,
74
-------
stress relaxation). It appears that testing methodology is related to
convenience, cost, and experience.
Controls
Considerable discussion was given to this subject. Several
people were of the opinion that untreated material should serve as the
test control, while others suggested that immersion in de-ionized
water, or even"tap water, would be more appropriate. Immersion in
de-ionized water had more support than any other method, but there was
no consensus. It was also suggested that samples be treated in water
prior to any subsequent exposure or test. FML material should be
retained for reference in a cool, dry, anaerobic environment.
Permeation
Several industry representatives felt that contamination in the
field caused by permeation is insignificant or Is not experienced. In
cases of leakage in ponds, the industry says it has always been able
to trace the leak back to breaks or tears in the liner. Others
suggested that permeation was a real problem. However, they did not
believe they knew enough about the subject to evaluate it. Most
believed that further work in this area should be conducted.
Other Comments ' .
Specimens for physical testing should not be cut from the product
sample before exposure to the waste fluid. Samples of the liner
materials should be cut out of coupons after the exposure period.
Some samples of the exposed liner materials should be dried in an
overt prior to testing to simulate material which is at the water line
in a pond and which may dry if the level drops.
5.6.3 Cost Profile
Cost of conducting compatibility tests was not discussed in depth
because of insufficient information. EPA (Washington) claims that a
current study being conducted using Method 9090 on five materials and
one waste will cost $15*000 including equipment. The cost for the
construction of the exposure units alone was about $6,000.
The industry representatives thought a figure of $20,000 to
$25,000 for five materials and one waste was a realistic cost. They
pointed out that only one type of liner material should be run in each
exposure unit. A multiple of tanks would be required for a large
number of samples, or samples of different types. They also expect
that the cost of storing and maintaining all of the exposure units
they would need would also be significant. Because of the require-
ments of Method 9090, a large number of samples would be required.
75
-------
Sample numbers would compound rapidly for multiple combinations -of
membranes and wastes for a given supplier required to conduct tests.
A laboratory toxic waste-handling and disposal problem would then
become, a real issue. Additional regulations for health, safety, and
environmental requirements would have to be observed.
5.7 TEST EQUIPMENT AND COST CONSIDERATIONS
Besides the technical evaluation of the 'test methods, equipment
requirements and cost should be considered. Basic equipment needs for
the tests are outlined in Tables 5.2-5.6. Specific equipment needs
vary depending upon the scope of the test, but .common items are
evident. For example, a container to hold the membrane sample in
contact with liquid, means of controlling conditions like temperature,
and apparatus, or tools for making measurements will all be required.
The degree of complexity of individual tests stipulates the sophisti-
cation of equipment needed. For example, the exposure system can vary
from glass Jars containing liner materials and the wastes placed in an
oven, to self-contained units or tanks for waste and liner which are
provided with temperature control and condensers to recycle the
vapors. Most test methods specify the parameters of the exposure, but
not the specific equipment type. Separate units are required for each
material and each waste. Any container used must be resistant to
potentially corrosive wastes. Means for handling • and storing the
exposure units during the exposure period are a practical matter.
Proper ventilation, for example, should be provided since many wastes
contain volatile constituents and may be toxic. ."'-:-.-•• ,.
The size of containers may be relatively small (0.5-1 liter jars)
or quite large (4-100 liter tanks). Construction of special sample
jigs and vessels is required in some tests, especially those where
one-side immersion is involved.
Tools to measure dimension, a balance to measure weight change,
and possibly a microscope to look at the surface characteristics of
membranes, are basic equipment for measurement and observation.
Also indispensable is stress-strain apparatus to measure tensile
strength, moduli, elongation, and other mechanical properties of a
membrane. A stress-strain apparatus, depending upon model and
features, can be priced from $15,000 to more than $60,000 if process
control is included. Except in a few instances where equipment
specifications or designated apparatus are included in the test
method, choices are left to the tester. In reality, the test methods
provide a protocol around which the actual test is fashioned.
Involved in the scope are types of membranes to be tested, quantity of
material, number of test specimens, numbers of waste liquid or chemi-
cals, required measurements, time of testing, and temperature condi-
tions.
76
-------
Reliable cose information for conducting a compatibility test is
unavailable at this time. In the absence of a generally accepted or
specified method, independent testing laboratories consulted were
reluctant to set a test cost. They were all quick to point out that
the cost would depend upon the choice of method, selection of liner
and wastes (or chemicals), and specified information needs.
Presently, chemical compatibility testing of FML does not seem to be a
routine practice for testing laboratories, and therefore they have had
little experience with selecting, applying, and costing these test
methods. FML manufacturers' test costs are, of course, proprietary,
as is private contractors' information. As experience with FML
testing in the industry increases, a better understanding of costs
will evolve. It is premature to expect reliable test cost information
at this point.
77
-------
6.0 GENERAL APPROACH TO COMPATIBILITY TESTING
6.1 THE SCOPE OF TESTING ' ; •
As pointed out throughout the previous sections of this report,
compatibility testing of FML is made complex by a number of factors
and interactions. Although apparatus and protocol may differ* current
test methods apply simple, familiar technological tests to evaluate
those FML materials being used in a demanding, new application. Each
of the tests described earlier appears to be useful for screening and
evaluation, but all are inadequate for predicting behavior patterns on
a truly long-term basis. Evaluation of test results is based on
limited experience, mostly from membrane manufacturers.
Figure 6.1, The Compatibility Test Scheme, outlines the complex
nature of compatibility testing. It is a summary of those factors to
be considered in making up a compatibility test. All the factors
described, as well as the interactions outlined, should be considered
if chemical compatibility is to be measured in its fullest sense. No
one current test takes into account the complete scheme, and it would
be impractical to conduct testing on 'this basis. Yet, all the
features shown are related to chemical compatibility and its assess-
ment. 'Current tests deal with only small segments of the scheme.
Whether or not parts of the scheme are equal to the whole (compati- -
bility) is still a matter for resolution. General discussions of
polymer testing are found in the literature (Refs. 20, 50, 51).
Chemical compatibility represents only one facet of polymer character-
ization. Features of the scheme are elaborated upon below and some
value judgments are made.
6.1.1 FML Material versus Liquid Challenge
Obviously, for chemical compatibility to exist, the liner
membrane must be matched to the waste or aggressive liquid. Selection
of the liner material results from general chemical resistance
guidelines developed by manufacturers. More detailed compatibility
tables may be useful for specific combinations of FML and challenge.
For instance, CPE membrane is not recommended for use in aromatic
hydrocarbons, and PVC is not useful with oxygenated or chlorinated
solvents. Ultimately, whether the liner is tested in field or
laboratory, the final test must be conducted with the service
chemical, waste, or leachate. The fact that most waste and leachate
are dilute solutions, may not be homogeneous, or may exhibit phase
separation, all pose additional considerations for the tester.
Concentrated solutions and dilute solutions of the same active
materials can produce different results.
78
-------
FML MATERIAL
Thermoplastic
Rubber
Reinforced vs. Unreinforeed
MEASUREMENTS
& OBSERVATIONS . . .
APPEARANCE
Color
Surface Character
Mass Features
Wear
DIMENSIONAL
Density /Weight
Linear Dimensions
Volume
STATIC PHYSICAL
Hardness
m**^m
MiM
1
MATERIALS CONTACT
Field Coupon
Laboratory Specimen
Immersion
Contact One Side
Jar, Fixture, or Dish
Strained vs. Unstrained
*
INFORMATION
PROCESSING
& EVALUATION
»
COMPATIBILITY
TEST
f%ATA
t
HM
MOM
LIQUID
CHALLENGE
Waste Liquid
Reagent
Water
L Circulated vs. Stagnant
.PARAMETERS . . .
TEMPERATURE
Ambient
Low
High
Cyclic
TIME
Hours
Days
Weeks
Years
CONCENTRATION
AkcnltiM
Compression Stress/Strain
Shear Stress/Strain
Ftexural Stress/Strain
Tear
Puncture
DYNAMIC PHYSICAL
Resiliency
Creep
Stress Relaxation
Set
Fatigue
Stress Cracking
MASS TRANSFER
Permeability
Diffusion
Leaching
CHEMICAL CHANGE
Molecular Weight
Viscosity
Chemical Analysis
Spectral Analysis
Concentrated'
Dilute
FML CONSTRUCTION
Thick-Thin
Reinforced
Unreinforeed
Laminated
ENVIRONMENTAL
Light
Ozone(oxygen)
pH
Wet/Dry
Cycling
SAMPLING & STATISTICS
Number of Samples
Sample Size
Form
FIGURE 6.1 THE COMPATIBILITY TEST SCHEME
79
-------
6.1.2 Parameters
The list of parameters represent factors that may be selected and
identified in the laboratory, but most likely they will be indeter-
minate in the field. Temperature in the field may actually fluctuate,
concentrations may change, and impinging environmental factors (e.g.,
light and ozone) may differ from day-to-day and site-to-site. If
waste at elevated temperature is present, then obviously testing
should be done at this temperature. However, testing chemical compat-
ibility at a high temperature to produce accelerated behavior can be
misleading, since high-temperature reactions in polymer materials may
bear no relation to reactions at lower temperatures. Above the glass
transition point of a polymer its chemical and physical behavior may
be altered and deviations from Arrheniun kinetics are possible.
Different properties of plastics and elastomer (visco-elastic
materials) do not vary with temperature uniformly.
Time for testing is basically a matter of choice. The longer the
time, the more closely it approaches expected or.desired service life.
A series of time points in testing can reveal if equilibrium is being
reached. However, practical considerations are important, and tests
are not likely to go on indefinitely before decision-making is
required.
The concentration of challenge ingredients may vary from- 1002
material to very dilute solutions of salts, acids, bases, and organic
chemicals encountered at the waste site. The *ol« «f crater as an
aggressor, or as a catalyst for chemical aggression, needs to be
carefully considered.
Consideration of the FML construction is important and necessary
to testing. Reinforced membrane, for instance, should not be tested
by immersion without sealing the edges, since chemicals can attack the
fiber scrim in a way unlike its action on the membrane surface.
Sealing edges with a coating of another polymer selected for chemical
resistance is not an easy task, and results are often unreliable. The
size of the test sample is important as well. If small samples cut
for subsequent machine testing are exposed, swelling or reaction will
produce a specimen considerably changed dimensionally from a control
or untreated sample. Subjecting larger specimens or sheets of mate-
rial to liquid contact followed by sample cutting produces a test
specimen-—in a different swollen or reacted state—that has another
set of dimensions. Measured values based on dimension and weight
changes will be different between the two techniques. If a sample is
too thin, or too thick for apparatus, fixtures, and handling, then
alterations in the test protocol are required.
80
-------
Environmental factors (e.g., light, ozone, site structure,
physical features) encountered in the field are not readily duplicated
in the laboratory and are generally neglected in compatibility test-
ing, even though they might ultimately affect properties and endurance
of the film.
Sampling and statistics are important features of the compati-
bility test design. Numbers of replicate samples and experimental
reproducibility are considerations for generating reliable data.
Obtaining representative, homogeneous, and characterized waste liquid
for the compatibility test is a major problem. The issue of sample
controls or standards for comparison cannot be overlooked, not only in
the specific test experiment, but for the manufactured materials as
well. It should be remembered that the FMLs are compounded, manu-
factured products that might vary in composition from batch to batch.
6.1.3 Measurements and Observations
Figure 6.1, under the heading of Measurements and Observations,
lists indicators of chemical compatibility. Only a few form the basis
for actual chemical compatibility tests now in use. After exposure,
appearance is the first clue to compatibility. Mass deformations and
color changes are immediate indicators that reaction has taken place.
Dimensional changes are also an immediate indicator of change."
Swelling of elastomers indicates sorption of a liquid. ' Swelled
membranes can behave differently from unswelled Material.
Traditionally, in plastic and rubber testing, the static physical
tests led by hardness and tensile stress/strain measurement are used
to indicate changes and degradations. The stress/strain properties
are related to the molecular makeup of the polymer, so that any attack
or alteration in the polymer structural configuration is manifested by
stress/strain changes. Most of these physical tests, whether in
tension, compression, shear, or bending (a combination of all three)
specified for polymers, have been adapted from time-honored methods
for metals. In polymer technology, it is assumed that a simple,
single test of short-tern mechanical nature at an arbitrary combina-
tion of time and temperature and in one physical state is useful for
evaluating the general performance of plastic material. Although the
industrial evaluation relies on these short-term mechanical tests,
most experts would agree that such tests only describe partial
behavior, and indeed might be unreliable predictors of actual
behavior. A special consideration is the fact that in mechanical
testing the value and meaning of observed changes are not clear. Is
no change in value necessary for compatibility, is 52, 10Z, etc.,
adequate, or is an equilibrium value sufficient? For some products
(e.g., pipes, gaskets, and seals) distinct values are acceptable, but
not for liners at this time.
81
-------
The dynamic physical properties represent a whole group of
features, more difficult to evaluate, not routinely conducted, or even
suggested, for compatibility assessment. The term dynamic is used to
describe the type test in which an elastomer is subjected to cyclic or
multi-directional deformation. Stress and strain, or other prop-
erties, are monitored during the test. These types of measurement are
characteristic of visco-elastic behavior and are time-related. Some
would say that dynamic measurements are better related to long-term
behavior. Considered under dynamic testing is the stress-cracking
phenomena important to the chemical compatibility testing of poly-
ethylene-based polymers. Stress-cracking is dynamic in the sense that
the aggression occurs in a flexed condition of the sample.
Mass-transfer properties in membrane films have been neglected in
compatibility measurement. However, if one goes back to the model of
the barrier membrane, then obviously, any movement of liquid through
the membrane via any mechanism negates the effectiveness of the FML.
Permeation and diffusion describe a mechanism, in simple form, whereby
the leachate or solvent molecules can slip through the tangled molec-
ular chains of a polymer and pass from one place to^another. Passage
of liquid may occur without chemical degradation, or solvation, in the
strict sense. Until recently, much good data of this type have not
been readily available for FML. Techniques for measuring permeability
and diffusion of small amounts of 'chemical are more sophisticated than
simple immersion and property testing, but are being Investigated for
this application (Refs. 2, 14, 15, 16). -, — .--.
-
All methods to this point are indirect measurements for chemical
compatibility. Chemical change can be measured directly by analytical
techniques that provide insight into the fundamental chemical and
physical makeup of the polymer. These techniques might include
chemical analysis, spectrographic characterization, molecular weight,
viscosity measurement, and the like. Such techniques are preferred by
researchers in the field of polymers rather than technologists. They
tend to be time-consuming and expensive. Such techniques, most useful
for single polymers, become difficult to interpret when applied to
mixtures and compounds found in commerce.
6.1.A Test Details
Many other details in experimental procedures need to be consid-
ered. Should the sample be tested by immersion or one-side contact?
In jars, cells, tubs, pouches, etc.? Should reagents or leachate be
replaced in time throughout the test? What degree of stress and rate
of strain should be used in testing? Should exposed samples be
examined in the wet or dry state? What ratio of liquid volume to
membrane is realistic? Should hydrostatic pressure be applied in
testing 'membranes? What about practical considerations, such as
handling specimens and toxic waste materials? The resolution of these
questions and others that can arise present real issues. Presently,
82
-------
they are dealt with on the basis of individual tests, and even at
that, in a peripheral manner.
In summary, attention oust be given to a variety of factors in
testing. They include:
• Compositional nature of test specimen (e.g., type of
polymer, type of blend or compound, degree of crosslinking);
• Structure of test specimen (reinforced versus non-
reinforced) ;
• Variability in test sample (lot-to-lot variation and field
variation);
• Preparation of sample (size, form, conditioning);
• Choice of liquid challenge (reagent versus leachate);
• Method of exposure (immersion versus one-side; laboratory
versus field);
• Conditions of exposure (concentration, temperature and
time); ' ..--.
• Mode of stressing sample if any;. "*
• Type of measurement (liquid saturation versus diffusive
transfer);
• Parameters measured (chemical versus physical);
and
i
• Variability in results.
6.2 THE CURRENT DILEMMA AND ROUTES TO RESOLUTION
The complexity of FML/waste compatibility testing has been
emphasized in this report. Most experts in the field would agree that
chemical compatibility testing is no simple matter. An interesting
letter (excerpted in Appendix A) received from West German workers
states a European opinion and reiterates the complexity.
Yet, to derive useful and reliable data, we are faced with
finding and applying a simple test methodology to a subject in which
the parameters are not well defined. The establishment of reliability
and the life-time prediction of FML in hazardous vaste containment is
expected to depend upon such evaluations. The several published ASTM
and international standards tests for chemical resistance of plastics
and rubbers have been considered a step in that direction.
83
-------
To meet the specific need, NSF 54 and Method 9090 have been
created. Of the identified tests, NSF Standard No. 54 and EPA test
method 9090 are the only two test methods currently directed to FML.
NSF 54 is based on ASTM D543 and ASTM P471 (both described in Section
5.2). A limited number of physical properties (tensile strength*
modulus, elongation, weight and dimensions, etc.) are measured after
an exposure by a specified technique. It is a short-term test (up to
7 days) conducted at 23°C and 50°C. Two important qualities (low
permeability and puncture resistance) for FML'were not included for
measurement. The NSF standard considers permeability measurements to
be meaningless, because FMLs are "impermeable." According to NSF, a
good test for puncture resistance does not exist. -SPA. Method 9090
also depends upon simple physical measurements after exposure.
Puncture resistance is measured. A more elaborate Jtest protocol and a
greater number of specimens compared to NSF 54 are specified. Test
time is longer (up to 120 days). Temperature is elevated to acceler-
ate matters. The NSF test is an immersion technique; the EPA, a
one-side exposure. Both procedures specify exposure to a sample of
actual waste fluid. Other variations in detail are seen from compari-
sons of descriptions in Section 5.2. Neither metho
-------
In assessing pipe liner elastomer, the authors paid attention to
the shape of the sorption curve. For pipe corrosion protection,
membranes that exhibited any peaks or net weight loss are rejected as
lining material. Interestingly enough, their thesis for chemical
testing elastomers is based primarily on weight change. Weight change
in rubbers has historically been used as a measure of performance. No
tensile or other test is required, although hardness may be measured.
This sequential chemical absorption technique; if applied to FML and
backed by experience, might provide the simplest approach to testing.
An alternate test approach in which the laboratory might be made
to simulate the site condition is to adopt the automated hydrostatic
flexible membrane test facility developed at the Bureau of Reclamation
(Ref. 53). In this case, a large membrane (*v20" dia.) can be tested
in the cell containing actual subsoil (Figure 6.2). A challenge
liquid under a hydrostatic load would stress the membrane. Tempera-
ture and test times could be altered as desired. After exposure, the
membrane would be removed and tested for appropriate properties.
Mm*
r
tflL.
Adapted from R.K. Frobel (Ref. 53).
Figure 6.2 Detailed Section Through a Vessel
85
-------
Other variations in testing that anticipate use conditions are
possible. Polymers in actual use, loaded or stressed, are known to
exhibit peculiar behavior patterns in accordance with the chemical and
environmental challenge, though no difference is seen in the results
of simple static (unloaded) immersion tests.
Okuda (Ref. 47) proposes that evaluation of chemical resistance
be made by chemical stress relaxation. This technique is summarized
in Section 5.3.26. He states that the stress relaxation test is
time-saving and a superior method for evaluating chemical resistance
of plastics. The stress-relaxation test is conducted directly on the
sample immersed in the liquid.
Figure 6.3 below from Okuda (Ref. 47), classifies patterns of
stress relaxation from which critical stress data can be derived. The
critical stress data become the index of chemical degradation.
Tl«t log t (hr)
Figure 6.3 Stress Relaxation Classification
Source: Ref. 47
In Figure 6.3, the standard curve (a) in air is the basis of
comparison. Usually, a relaxation limit exists, and the curve becomes
concave. This relaxation limit is related to the degree of movement
of molecules after a long period. Curve (b) is downward from the
curve in air, and the critical initial stress decreases because of a
slight swelling. However, even in (b), the swollen state, a limit
similar to the relaxation limit in (a) is observed. According to
Okuda (Ref. 47), plastics in this state may be used safely in the
chemical agent if the allowable stress chosen is at relatively low
level. Curve (c) describes the case where the molecular structure of
the polymer is weakened significantly by chemical degradation, and
curve (d) shows how the stress is reduced remarkably by environmental
86
-------
stress cracking. If patterns (c) and (d) are observed, then the
plastic or elastomer is not compatible and should not be used for the
corresponding environment. We know of no commercially available
apparatus for carrying out Okuda's procedure, but a test device could
be devised around currently available stress/strain instrumentation.
w
The availability of new instrumentation expands the range of
polymer testing. New test techniques may provide better compatibility
characterization. For instance, dynamic mechanical analysis (DMA) is
a relatively new technique for measuring fundamental properties of
polymeric materials, e.g., elasticity and damping. Apparatus intro-
duced by DuFont permits properties of material to be measured easily
and automatically on a micro-processor-controlled unit (the type of
DMA test is determined by the choice of software). The DMA technique
separates the visco-elasticity of a material into two components of
modulus — a part related to. elastic modulus and a part related to the
damping or viscous component. These visco-elastic measurements are
very sensitive indicators of internal structure, and as such can be
used to develop structure/property relationships of materials.
Although DMA measurements can be made isothermally, the ability to
measure visco-elastic . or rheological properties as they vary with
temperature makes the DMA technique especially useful for predicting
end-use product performance and determining effects of aging, chemical
resistance, solvation, and the like.
Figures 6.4 and 6.5 show DMA results for unreinforced 80-mil
thick, commercial HDPE liner before and after exposure to Laktane
solvent (a mixture of aliphatic C. and CL hydrocarbons, elong with
cycloparaffins and aroma tics; available from Exxon). Exposure was
made by suspending a sample of the HDPE in a jar of Laktane at 20°C
for about 24 hours (overnight soak) . The sample was then removed and
evaluated by DMA for comparison. In the DMA apparatus, three
properties (tensile storage modulus, tensile loss modulus, and log
[tan delta]) are plotted simultaneously over the temperature range.
In comparing the exposed sample to the unexposed HDPE, note the change
in moduli even after only 24 hours of liquid contact. The percentage
change observed at 20° C amounts to a loss of 43% for both tensile
storage modulus and tensile loss modulus. This change means that
visco-elastic behavior of the liner has been altered by absorption of
the solvent. The significance of the change remains to be determined.
This exploratory experiment suggests DMA can be applied to compati-
bility testing.
Resolution of the dilemma in compatibility testing is not immi-
nent. Industry has had experience and is comfortable with relatively
simple immersion or one-side exposure tests. In the United States,
the NSF and EPA are the only organizations that have seriously
considered— and written — a test methodology for FML. The Germans also
appear to be active in FML testing. Current tests probably do not
meet all criteria for determining compatibility. No test fully
87
-------
00
oo
SampUi SAMPLE A
Six.i L14.86 V 13.4 T 2.01
Rat., 5.0 DEG/MIN
Program! DMA Modulo* ft Damping V2.0
• DaUi 20~S»p-83 Tim., 0,51, 13
DMA FlUl ADL-01 DEMO *01
Op.ratori RDC
Plott.d, 20-S.p-83 12,01,55
0
o
j
to
fl
•
0
4 1 t I 1 -I
0*a AMI t 0.20 0.4
0.24
0.20
fe
v
5
<-«
•3
•
0
-120
0.ie
0.12
0.08
0.04 il*
0.00
in. -11'''4
DuPont 1090
Figure 6.4 DMA - Unexposed HOPE
Source: Arthur D. Little, Inc.
-------
00
S«i.Pl m SAMPLE AA.AKTANE
S|x«i L14.73 W 13.13T 2.05
Rot*i 5.0 DEG/MIN
Program DMA Modulo* & Damping V2.0
DMA
DoUi 20-S«p-83 TiM«i 12i29i30
FtUi AOL. 02 DEMO .01
Operator* RDC
Plotted. 20-S«p-83 13.56,09
4 1 1 1 I—H »—-H 1 1- 0.29
fe
TJ
0
0
•*»
en
0*o Anp * 0.20
0.2*2
o
• • 0.20 •-*
0.18
•
o
-100
0.12 t
0.08
0.04
-1.0 0.00
100 120
DuPanfc 1090
Figure 6.5 DMA - Exposed HOPE
Source: Arthur D. Little, Inc.
-------
predicts behavior or adequately establishes life-time expectation.
Laboratory screening tests do not necessarily correlate with field
testing (required). The comments of FML technologists (see Section
5.6) describe as well as any the present and future test needs.
Testing should be conducted at three levels to provide direction for
those concerned:
"l) Short term (30 days)
2) Intermediate (4 months)
3) Long term (>4 months).
Industry tests and NSF 54 deal with the short term; Method 9090 and
some .international tests deal with the intermediate and longer-term.
None has been proven for life-time prediction or evaluation. None of
the tests deals with all parameters.necessary to characterize compati-
bility (e.g., stress-cracking, permeability and dynamic behavior).
Aside from refining present test methodology to meet immediate
demands, and for building a technological and historical baseline,
research is required in several areas if chemical .compatibility is to
be fully understood and measured. As examples, areas for investiga-
tion might include liquid transport phenomena, application of dynamic
testing (e.g., .yisco-elastic behavior), development of long-term
testing and data, and exploration of new equipment and methods for
applicability. The result of current and future investigations into
FML performance in a chemical environment will be a better under-
standing and a. test(s) satisfactory to all.
90
-------
REFERENCES
1. . Lyman, W.J.,' et al- Expected Life of Synthetic Liners and Caps.
Unpublished Draft Report. EPA Contract Ho. 68-01-6160; Work
Order No. 14. U.S. Environmental Protection Agency, Office of
Water Regulations and Standards, Washington, D.C. March 31,
1983. 170 pp.
2. Schwope,. A.D., et al. Analysis of Flexible Membrane Liner
Chemical Compatibility Tests. Unpublished Draft Report. .EPA
Contract No. 68-01-6160; Work Order No. 14. U.S. Environmental
Protection Agency, Office of Water Regulations and Standards,
Washington, D.C. March 31, 1983. 77 pp.
3. Haxo, Jr., H.E. Testing of Materials for Use in the Lining of
Waste Disposal Facilities, pp 269-292. Hazardous Solid Waste
Testing: First Conference. ASTM Symposium, Ft. Lauderdale, FL,
14-15 January 1981. American Society for Testing and Materials,
Philadelphia, PA. 1981. 386 pp.
4. Rays, W.B. Construction of Linings for Reservoirs, Tanks, and
Pollution Control Facilities. John Wiley and Sons, Inc.,
New York, NY. 1977. 379 pp.
5.. Schwope, A.D., et al. Compatibility of Flexible Membrane Liners
with Chemicals and Wastes. Report under review. EPA Contract
No. 68-01-6160; Work Order No. 16. U.S. Environmental Protection
Agency, Office of Water Regulations and Standards, Washington,
DC. August 31, 1984. 221 pp.
6. A series of articles by several authors. Journal of Chemical
Education. 58:836-955, November 1981.
7. Shuckrow, A.J., A.P. Pajak, and C.J. Touhill. Hazardous Waste
Leachate Management Manual. Noyes Data Corporation, Park Ridge,
NJ. 1982. 379 pp.
8. Ghassemi, M., et al. Compilation of Hazardous Waste Leachate
Data. Unpublished Draft Report. EPA Contract No. 68-02-3174.
U.S. Environmental Protection Agency, Washington, D.C. April
1983. 54 pp and Appendices.
9. Landreth, R. (Project Officer). Lining of Waste Impoundment and
Disposal Facilities (revised edition). SW-870. U.S. Environ-
mental Protection Agency, Office of Solid Waste and Emergency
Response, Washington, D.C. March 1983. 448 pp.
91
-------
10. Eby, R.K. Durability of Macromolecular Materials. ACS Symposium
Series* No. 95. American Chemical Society, Washington, D.C.
1979. 476 pp.
11. Schnabel, W. Polymer Degradation. Principles and Practical
Applications. MacMillan Publishing Company, Inc., New York, NY.
1981. 227 pp.
12. Bartenev, G.M., and Yu S. Zuyev. Strength and Failure of Visco-
Elastic Materials. Pergamon Press, New York, NY. 1968. 419 pp.
13. Roberts, S.A., N.A. Nelson, and H.E. Haxo, Jr. Evaluation of a
Waste Impoundment Liner System After Long-term Exposure. EPA
600/9-83-018. Proc. Ninth Annual Research Symposium, Land
Disposal of Hazardous Waste. U.S. Environmental Protection
Agency, Municipal.Environmental Research Laboratory, Cincinnati,
OH. 1 September 1983. 172-187 pp.
14. Haxo, Jr., H.E., J.A. Miedema, and N.A. Nelson. Permeability of
Polymeric Membrane Lining Materials. Proc. International
Conference on Ceomembranes, June 20-24, *1984, Denver, CO.
Industrial Fabrics Association International, St. Paul, MN.
1984. 151-156 pp.
15. • August, H., and R. Tatzky. Permeabilities of Commercially
Available Polymeric Liners for Hazardous Landfill Leachate
Organic Constituents. Proc. International „ Conference on
Geomembranes, June 20-24, 1984, Denver, ifib.'^llSiffial Fabrics
Association International, St. Paul, MN. 1984. 163-168 pp.
16. Giroud, J.P. Impermeability: The Myth and • Rational Approach.
Proc. International Conference on Geomembranes, June 20-24, 1984,
Denver, CO. Industrial Fabrics Association International,
St. Paul, MN. 1984. 157-162 pp.
17. Bell, G.R. Standard Tests for Plastics. How Useful is the Data?
Part I. Plastics World. 38(4):60-65, April 1980.
18. Bell, G.R. Standard Tests for Plastics. How Useful is the Data?
Part II. Plastics World. 38(5):58-61, May 1980.
19. O'Toole, J.L. Selecting Plastics for Chemical Resistance.
1983-1984 Modern Plastics Encyclopedia. 60(10A):411-416,
October 1983.
20. Brown, R.P. Physical Testing of Rubbers. Applied Science
Publishers Ltd., London. 1979. 327 pp.
21. Seymour, R.B. Plastics vs. Corrosives. SPE Monograph. John
Wiley & Sons, New York, NY. 1982. 285 pp.
92
-------
22. Nielsen, I.E. Mechanical Properties of Polymers. Reinhold
Publishing Corporation, New York, NY. 1962. 274 pp.
23. Cassidy, P.E., and T.M. Aminabhavi. Water Permeation through
Elastomers and Plastics. Rubber Chemistry & Technology.
56(3):591-618. 1983.
*
24. Eichhorn, R.M. Measurement of Water Vapor Transmission through
Polyethylene Electrical Insulation. Polymer Engineering 4
Science. 10(l):32-37, January 1970.
25. ISO International Standard 175. Plastics-Determination of the
Effects of Liquid Chemicals, Including Water. 1st Edition. Ref.
No. ISO 175-1981(E). International Organization for Standard-
ization, Geneva, Switzerland. 1 July 1981. 12 pp.
26. ISO International Standard 1817. Vulcanized Rubbers—Resistance
to Liquids—Methods of Test. 1st Edition. Ref. No. ISO 1817-
1975(E). International Organization for Standardization, Geneva,
Switzerland. 15 October 1975. 10 pp.
27. German Standard DIN 53 521. Testing of Rubber and Elastomers.
Determination of the Resistance to Liquids, Vapours and Gases.
DIN Deutsches Institut fur Normung e.v., Berlin. April 1979^
12-pp.
28. German Standard DIN 53 532. Testing of Elastomers. Determina-
tion of Permeability of Elastomer Sheeting to Liquid Fuels.
DIN Deutsches Institut fur Normung e.v., Berlin. September 1975.
3 pp.
29. British Standard BS 4618:Section 4.1:Part 4. Environmental and
Chemical Effects. Chemical Resistance to Liquids. British
Standards Institution, London. 1972. 12 pp.
30. British Standard BS 5173:Part 5. Methods of Test for Hoses—
Chemical Resistance Tests. British Standards Institution,
London. 1977. 6 pp.
31. EPA Method 9090. Compatibility Test for Wastes and Membrane
Liners. A Proposed Method. U.S. Environmental Protection
Agency, Office of Solid Waste, Washington, DC. Undated. 10 pp.
32. NSF Standard Number 54. Flexible Membrane Liners. National
Sanitation Foundation, Ann Arbor, MI. November 1983. 26 pp and
Appendices.
93
-------
33. ASTM Standard Test . Method D543. Resistance of Plastics to
Chemical Reagents. (Current edition effective August 24, 1967).
1983 Annual Book of ASTM Standards. 08(01):196-201, 1983.
American Society for Testing and Materials, Philadelphia, PA.
.r
34. ASTM Standard Test Method D814. Rubber Property—Vapor
Transmission of Volatile Liquids. (Current edition. approved
January 8, 1981). 1983 Annual Book of ASTM Standards.
09(01):188-190, 1981. American Society for Testing and
Materials, Philadelphia, PA.
35. ASTM Standard Test Method G20. Chemical Resistance of Pipeline
Coatings. (Current edition approved December 30, 1977). 1983
Annual Book of ASTM Standards. 06(01):992-993, 1983, American
Society for Testing and Materials, Philadelphia, PA. '
36. ASTM Standard Test Method D471. Rubber Property—Effect of
Liquids. (Current edition approved March 30, 1979). 1983 Annual
Book of ASTM Standards. 09(01):112-120, 1983. American Society
for Testing and Materials, Philadelphia, PA. ******•*"
37. Military Specification MIL-T-6396D. Tanks, Fuel, Oil, Water-
Alcohol, Coolant Fluid, Aircraft, Non-Self-Sealing, Removable
Internal. 30 August 1974. 43 pp. Department of Defense, Naval
Air Systems Command, Engineering Division, Standardization
Section, Code AIR-52021, Department of the »avyy*i*Mhington, DC.
38. Schlegel Laboratory Test Procedure. Test Procedure for
Determining Chemical Resistance of Flexible Itembrane Liners.
Schlegel Lining Technology, Inc., The Woodlands, TX. December 2,
1980. 3 pp.
39. J.P. Stevens Test Methods for Determining Lining Compatibility to
the Chemical Environment. Bulletin and Correspondence.
J.P. Stevens & Company, Inc. Elastomeric Products Department,
Easthampton, MA. (Received 1984).
40. Gundle Laboratory Test. Chemical Compatibility. Cundle Lining
Systems, Inc., Houston, TX. Undated. 1 p.
41. Haxo, Jr., H.E., et al. Liner Materials Exposed to Municipal
Solid Waste Leachate. EPA 600/S2-82-097. U.S. Environmental
Protection Agency, Municipal Environmental Research Laboratory,
Cincinnati, OH. March 1983.
94
-------
42. Bellen, G., and C. Rebecca. EFA/NSF Study of Chemical Resistance
of Flexible Membrane Liners. First Quarterly Report. EPA
Contract No. CR-810-727-01-0. U.S. Environmental Protection
Agency, Municipal Environmental Research Laboratory, Cincinnati,
OH; National Sanitation Foundation, Ann Arbor, MI. October 1983.
14 pp plus attachments.
43. Young, P.J., and G. Baldwin. An Assessment of Two High-Density
Polyethylenes as Landfill Liners by Application of an Accelerated
Test. G-2378. Scientific Administration Officer, AERE, Harwell,
Oxfordshire, England. June 1982. 19 pp.
44. Carpenter, C.N., and A.O. Fisher. Sequential Chemical Absorption
Techniques for Evaluating Elastomer. Materials Performance.
20:40-45, January 1981.
45. Minter, H.F., and J.F. Meier. Guide to Fluid Resistance of
Rubber and Elastomers. Materials and Engineering. 81:32-35,
January 1975.
46. Environmental Stress-Cracking by Creep Rupture Tests. Selecting
Plastics for Chemical Resistance. 1983-1984 Modern Plastics
Encyclopedia. 60(10A):414-415, October 1983.
47. Oku da, S. Evaluation of Chemical Resistance of Plastics by the
Stress Relaxation Method and its Application to Engineering
Design, pp 70-73. Managing Corrosion with Plastics. Combined
Vols. 1, 2, and 3. National Association of Corrosion Engineers,
Houston, TX. 1977. 313 pp.
48. Crissman, J.M. A New Test Method for Determining Environmental
Stress-Crack Resistance of Ethylene-based Plastics. J. Testing &
Evaluation. 11(4):273-278, July 1983.
49. Titov, V.V. A Review of Methods for the Testing and Study of
Environmental Stress Failure in Thermoplastics. Plastics &
Polymers. 98-101, June 1975.
50. Ives, G.C., J.A. Mead, and M.M. Riley. Handbook of Plastics Test
Methods. CRC Press, Cleveland* OH. 1971. 476 pp.
51. International Symposium on Plastics Testing and Standardization.
ASTH Special Technical Publication No. 247. American Society for
Testing Materials, Philadelphia, PA. 1959. 269 pp.
•
52. Fisher, A.O., and C.N. Carpenter. Advances in the Chemical
Testing of Elastomers. Materials Performance. .20:29-35,
August 1981.
95
-------
53. Frobel, R.K. Design and Development of an Automated Hydrostatic
Flexible Membrane Test Facility. REC-ERC-80-9. U.S. Department
of Interior, Engineering and Research Center. Materials Science
Section, Denver, CO. January 1981. 25 pp.
96
-------
APPENDIX A
RESPONSE TO AN INQUIRY
FROM
ARTHUR D. LITTLE, INC.
BY
THE FEDERAL INSTITUTE FOR MATERIALS TESTING (BAM), BERLIN
(translated from the German)
Communication from Dr.-Ing. H. August, dated 2 November 1983,
Federal Institute for Materials Testing - Bundesanstalt fur
Materialprufung (BAM); Elastomers, Plastics and Coating Materials
Section; Unter den Eichen 87, D-1000 Berlin 45.
V The product chemical compatibility lists published
by raw material manufacturers and manufacturers of waste disposal site
liners and barriers take into account only chemical effects, to the
exclusion of any physical stress imposed simultaneously. Information
pertains only to the effects of individual substances or chemicals on
membranes, and in no way to mixtures of substances which may be
present in leachate, nor the possible synergistic «*££«cts of such
mixtures on polymeric membrane. These compatibility charts are.
therefore suitable only for initial screening and selection purposes.
"Practically, it is extremely difficult, usually impossible, to
furnish precise proof of long-term suitability for a particular
polymeric barrier material. In our view this is primarily attrib-
utable to the following reasons:
"The service life desired for polymeric liners (minimally 50
years and preferably 100-150 years) is beyond the scope of current
test methods. All known stress-strain test procedures for testing of
plastics (e.g., DIN 53 444) permit reliable extrapolation of service-
ability one to 10 years or more, with maximum forecasts of up to 20
years if the duration of testing is to still remain within economi-
cally justifiable limits. Increasing test temperatures for the
purpose of accelerating the test extends the extrapolation period
somewhat, but this extrapolation must be applied with great care since
it presupposes validity of Arrheniun behavior at the elevated temper-
ature.
"Another difficulty is that the requirements with respect to
physical and chemical stress over the life-span of the polymeric
barrier is generally indeterminate. Because of the great diversity of
organic and inorganic compounds that may be involved, simulation in
laboratory experiments is a complex matter, is inadequate, and is
poorly representative. It is known that no representative leachate
from municipal waste disposal sites exists for testing membranes. The
97
-------
composition of leachate is dependent on the place and location of its
sampling within the waste site* varies from one disposal site to
another, and is subject after sampling to aerobic and anaerobic
transformations.
»•
"Even though it follows from the reasons presented that there is
no precise test method that provides, at reasonable cost and within a
realistic time frame, long-term forecasts concerning' the suitability
of polymeric barriers,* the possibility, nevertheless, exists of
employing such barriers at the waste disposal site. In our view,
selection should be limited to materials that have shown themselves to
be outstanding over a period of ten years or more in the field of
chemical storage and transport. Among the latter are high-density
polyethylenes (HDPE), for which proven bonding techniques exist in
tunnel and canal construction (e.g., extrusion fusing). We have no
knowledge of any properties of household waste that would cause HDPE
to lose its retaining and sealing capabilities for fifty years and
more, so long as it is properly installed, its period of exposure to
sunlight is kept as short as possible, and the FE sheeting is
adequately UV-stabilized with carbon black. The environment of the PE
membrane at the waste site during its period of use is largely
anaerobic in our view, and this prevents significant oxidative
degradation for a considerable length of time.
"When HDPE films are used in industrial waste 'sites, we consider
necessary substantially more testing. Unless many years of experience
are available as a basis for reference, subst«acM^*iHl^»lxtures to be
contained at the site, in concentrated form if possible, should be
employed in the test. Investigations concerning possible oxidative
degradation of the HDPE liner should be carried out especially when
strongly oxidizing acids are present "
98
------- |