ASTM F2023-00
(Test Method)Standard Test Method for Evaluating the Oxidative Resistance of Crosslinked Polyethylene (PEX) Tubing and Systems to Hot Chlorinated Water
Standard Test Method for Evaluating the Oxidative Resistance of Crosslinked Polyethylene (PEX) Tubing and Systems to Hot Chlorinated Water
SCOPE
1.1 This test method describes the general requirements for evaluating the long-term, chlorinated water, oxidative resistance of cross-linked polyethylene (PEX) tubing produced in accordance with Specification F876 or PEX tubing/fitting systems in accordance with Specification F877 used in hot-and-cold water distribution systems by exposure to hot, chlorinated water. This test method outlines the requirements of a pressurized flow-through test system, typical test pressures, test-fluid characteristics, failure type, and data analysis.Note 1
Other known disinfecting systems (chlorine dioxide, ozone, and chloramine) are currently used for protection of potable water; however, free-chlorine is by far the most common system in use today. Disinfecting systems other than chlorine have not been evaluated by this method.
1.2 Guidelines and requirements for test temperatures, test hoop stresses, and other test criteria have been established by prior testing of PEX tubing produced by the three most common commercial methods of cross-linking: silane, peroxide, and electron-beam (see Note 2). Other related system components that typically appear in a PEX hot-and-cold water distribution system can be evaluated with the PEX tubing. When testing PEX tubing and fittings as a system, it is recommended that the anticipated end-use fitting type(s) and material(s) be included in the test circuit since it is known that some fitting types and materials can impact failure times. Specimens used shall be representative of the piping product(s) and material(s) under investigation.
Note 2--The procedures described in this test method (with some modifications of test temperatures or stresses, or both) have been used to evaluate pipes manufactured from polybutylene (PB), polyethylene (PE), polypropylene (PP), multilayer (polymer-metal composite), copper, and stainless steel.
1.3 This test method is applicable to PEX tubing and systems used for transport of potable water containing free-chlorine for disinfecting purposes. The oxidizing potential of the test-fluid specified in this test method exceeds that typically found in potable water systems across the United States.
1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information purposes.
1.5 The following precautionary caveat pertains only to the test method portion, Section 12, of this specification.This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation:F2023–00
Standard Test Method for
Evaluating the Oxidative Resistance of Crosslinked
Polyethylene (PEX) Tubing and Systems to Hot Chlorinated
Water
This standard is issued under the fixed designation F 2023; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (ϵ) indicates an editorial change since the last revision or reapproval.
1. Scope thetest-fluidspecifiedinthistestmethodexceedsthattypically
found in potable water systems across the United States.
1.1 This test method describes the general requirements for
1.4 The values stated in inch-pound units are to be regarded
evaluating the long-term, chlorinated water, oxidative resis-
as the standard. The values given in parentheses are for
tance of cross-linked polyethylene (PEX) tubing produced in
information purposes.
accordance with Specification F 876 or PEX tubing/fitting
1.5 The following precautionary caveat pertains only to the
systems in accordance with Specification F 877 used in hot-
test method portion, Section 12, of this specification.This
and-cold water distribution systems by exposure to hot, chlo-
standard does not purport to address all of the safety concerns,
rinated water. This test method outlines the requirements of a
if any, associated with its use. It is the responsibility of the user
pressurized flow-through test system, typical test pressures,
of this standard to establish appropriate safety and health
test-fluid characteristics, failure type, and data analysis.
practices and determine the applicability of regulatory limita-
NOTE 1—Other known disinfecting systems (chlorine dioxide, ozone,
tions prior to use.
and chloramine) are currently used for protection of potable water;
however, free-chlorine is by far the most common system in use today.
2. Referenced Documents
Disinfecting systems other than chlorine have not been evaluated by this
2.1 ASTM Standards:
method.
D 1600 Terminology for Abbreviated Terms Relating to
1.2 Guidelines and requirements for test temperatures, test
Plastics
hoop stresses, and other test criteria have been established by
D 2122 Test Method for Determining Dimensions of Ther-
prior testing of PEX tubing produced by the three most
moplastic Pipe and Fittings
common commercial methods of cross-linking: silane, perox-
E 177 Practice for Use of the Terms Precision and Bias in
ide, and electron-beam (see Note 2). Other related system
ASTM Test Methods
components that typically appear in a PEX hot-and-cold water
F 412 Terminology Relating to Plastic Piping Systems
distribution system can be evaluated with the PEX tubing.
F 876 Specification for Cross-linked Polyethylene (PEX)
When testing PEX tubing and fittings as a system, it is
Tubing
recommended that the anticipated end-use fitting type(s) and
F 877 Specification for Cross-linked Polyethylene (PEX)
material(s) be included in the test circuit since it is known that
Plastic Hot- and Cold-Water Distribution Systems
some fitting types and materials can impact failure times.
F 948 Test Method for Time-to-Failure of Plastic Piping
Specimensusedshallberepresentativeofthepipingproduct(s)
Systems and Components Under Constant Internal Pres-
and material(s) under investigation.
sure With Flow
NOTE 2—The procedures described in this test method (with some 2.2 ISO Standards:
modifications of test temperatures or stresses, or both) have been used to
ISO 9080 Thermoplastic Pipe for Transport of Fluids—
evaluate pipes manufactured from polybutylene (PB), polyethylene (PE),
Methods of Extrapolation of Hydrostatic Stress Rupture
polypropylene (PP), multilayer (polymer-metal composite), copper, and
Data to Determine the Long Term Strength of Thermo-
stainless steel.
plastic Pipe
1.3 This test method is applicable to PEX tubing and
ISO 13760 Plastic Pipe for the Conveyance of Fluids Under
systems used for transport of potable water containing free-
Pressure—Miners Rule—Calculation Method for Cumu-
chlorine for disinfecting purposes. The oxidizing potential of
lative Damage
Annual Book of ASTM Standards, Vol 08.01.
1 3
This test method is under the jurisdiction of ASTM Committee F17 on Plastic Annual Book of ASTM Standards, Vol 08.04.
Piping Systems and is the direct responsibility of Subcommittee F17.40 on Test Annual Book of ASTM Standards, Vol 14.02.
Methods. Available from theAmerican National Standards Institute, 11W. 42nd St., 13th
Current edition approved June 10, 2000. Published September 2000. Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
F2023–00
2.3 Plastics Pipe Institute (PPI) Document: 3.1.5 long-term oxidative resistance, n—the extrapolated
TN-16 Rate Process Method for Projecting Performance of time-to-failure prediction as determined by analysis of time-
Polyethylene Piping Components to-failure test data by multiple linear regression utilizing the
2.4 American Water Works Association (AWWA) Docu- rate process method of PPI TN-16 or Model Q of ISO 9080.
ment: Where applicable, application of Miners Rule in accordance
1996 WATER:\STATS Survey with ISO 13760 can be used to estimate time-to-failure at
several differing conditions of temperature or stress, or both.
3. Terminology
3.1.6 multiple linear regression, n—a three or four coeffi-
3.1 Definitions—Definitions are in accordance with Termi-
cient mathematical model used to analyze time-to-failure data
nology F 412F 412 and abbreviations are in accordance with
from different temperatures and stresses to extrapolate pro-
Terminology D 1600D 1600, unless otherwise indicated.
jected time-to-failure at selected temperatures or stresses.
3.1.1 brittle failure (Stage II), n—failure in the tubing wall
3.1.7 Miners Rule, n—a mathematical method for estimat-
that is characterized by little or no material deformation in the
ing the cumulative, irreversible damage that results from
failure area and is the result of a single crack emanating from
exposure to each of several differing conditions of stress or
the interior of the tubing to the outside surface typically
temperature, or both.
resulting in a pinhole leak, see Fig. 1. Brittle failures produced
3.1.8 oxidation reduction potential (ORP), n—a measure of
with this test method shall not be used for data analysis.
the total oxidizing power of a solution by means of a
3.1.2 ductile failure (Stage I), n—failure in the tubing wall
platinum-redoxelectrode.ForafurtherexplanationofORPsee
that is characterized by obvious localized deformation of the
Appendix X2.
material visible with the unaided eye, see Fig. 1. Ductile
3.1.9 unaided eye, n—observable without visual enhance-
failures produced with this test method shall not be used for
ment beyond correction for normal vision.
data analysis.
3.1.3 environmental or oxidative failure (Stage III),
4. Summary of Test Method
n—failure in the tubing wall characterized by a large number
of cracks emanating from the interior surface of the tubing
4.1 ThePEXtubingortubing/fittingassembliesareexposed
wall, see Fig. 1.
to pressurized test-fluid until failure. All time-to-fail data used
3.1.3.1 Discussion—StageIIIfailuresmayalsobeidentified
for analysis shall be the result of oxidative degradation (Stage
by a color shift in the failure area (typically brown or
III). A minimum number of test temperature and hoop stress
reddish-brown). Identification of oxidative failure, when not
conditions are required to allow accurate data analysis and
obvious by inspection with the unaided eye, can be performed
time-to-failure extrapolations.
with a 25X microscope or other similar device yielding the
same level of magnification. Only Stage III environmental
5. Significance and Use
failures shall be used for data analysis.
5.1 Environment or oxidative time-to-fail data derived from
3.1.4 hot-and-cold water distribution system, n—a combi-
this test method, analyzed in accordance with Section 13, are
nation of components such as tubing, fittings, valves, and so
suitable for extrapolation to typical end-use temperatures and
forth, that when installed as a complete system, make up the
hoop stresses. The extrapolated value(s) provides a relative
interior water supply system of a commercial or residential
indication of the resistance of the tested PEX tubing or system
structure.
to the oxidative effects of hot, chlorinated water for conditions
equivalent to those conditions under which the test data were
Available from the Plastics Pipe Institute,
obtained. The performance of a material or piping product
Available from the American Water Works Assn.,
under actual conditions of installation and use is dependent
upon a number of factors including installation methods, use
patterns, water quality, nature and magnitude of localized
stresses, and other variables of an actual, operating hot-and-
coldwaterdistributionsystemthatarenotaddressedinthistest
method. As such, the extrapolated values do not constitute a
representation that a PEX tube or system with a given
extrapolated time-to-failure value will perform for that period
of time under actual use conditions.
6. Apparatus
6.1 Pressurized Flow-Through Test System—Asystemcom-
prised of the necessary pump(s), fittings, piping, heaters,
sensors, and meters that is capable of maintaining the required
test pressures within the tolerance specified in 9.1.4, the
required test temperatures within the tolerance of 9.1.3, and
flow the test-fluid through the specimens continually at a flow
FIG. 1 Pictorial Illustration of Failure Types rate within the tolerance specified in 9.1.5. Cyclic pressure
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
F2023–00
NOTE 4—Prior testing indicates that for the test temperatures stated in
variations, such as those produced by some pumping systems,
7.4.2, hoop stresses to yield Stage III failures within reasonable testing
shall not produce pressure excursions that exceed the tolerance
times are between 160 psi (1.10 MPa) and 400 psi (2.76 MPa). For a true
stated in 9.1.4.
SDR9 tube, those hoop stresses correspond to test pressures of 40 psig
6.1.1 Recirculating Test System—A flow-through test sys-
(275.9kPa)to100psig(689.7kPa).Ifaselectedtesthoopstressproduces
tem that repeatedly reconditions the test-fluid and passes it
Stage I or Stage II failures, the stress will need to be reduced to produce
through the specimens. For purposes of this test method, the
Stage III failures at all temperatures.
test-fluid shall be monitored at a sufficient frequency to ensure
7.4.2.1 Relationship of Internal Pressure to Hoop Stress—
that it continuously meets the test-fluid parameters and water
The hoop stress in the tubing wall is calculated by the
quality criteria. A portion of the total system volume shall be
following expression, commonly known as the ISO equation:
purged and replaced with fresh test-fluid continually.
2S/P 5 DR 2 1 (1)
6.1.2 Single-Pass Test System—A flow-through test system
that passes the test-fluid through the specimens only once and or
is discarded.
2S/P 5 ~D /t! 2 1 (2)
o
6.2 Specimen Holders—Test specimens shall be supported
where:
to minimize or eliminate externally induced stresses. Speci-
S = stress in the circumferential or hoop direction, psi
mens shall be allowed to freely expand bi-directionally
(MPa),
P = internal pressure, psig (kPa),
7. Sampling, Test Specimens, and Test Units
t = minimum wall thickness, in. (mm),
7.1 Sampling—Select at random, a sufficient amount of
DR = dimension ratio, DR, and
tubingtosatisfythespecimenrequirementsofthistestmethod.
D = average outside diameter, in. (mm).
o
When testing as a system, randomly select a sufficient quantity
of fittings.
8. Calibration and Standardization
7.2 Test Specimen Size—The PEX tubing specimens shall
8.1 Measuring Equipment—All measuring and testing
be 12 to 18 in. (300 to 460 mm) in length between fitting
equipment having an effect on the accuracy or validity of the
closures or between fitting joints.
calibrations or tests shall be calibrated or verified, or both,
7.2.1 Dimensions Measurement—Measure and record the
before being put into service.
critical dimensions for tubing and fittings. For tubing, measure
the average outside diameter and wall-thickness in accordance
9. Test Fluid
with Test Method D 2122D 2122. For fittings, measure those
dimensions critical to the function of the joint, as well as 9.1 Internal Test Fluid—The test fluid shall be reverse
minimum body wall thickness. osmosis (RO) or deionized (DI) water prepared in accordance
7.3 Testing as a System—When testing PEX tubing and with 9.1.1, or potable water (tap water) prepared in accordance
related system components (such as fittings) as a system, the with 9.1.2.
other components shall be attached to the PEX tubing in the 9.1.1 RO or DI Water Test-Fluid Preparation—Test fluid
same manner as in actual service. For fittings, the particular prepared from RO or DI water shall have a pH in the range
fitting style shall be installed in accordance with the manufac- from 6.5 to 8.0 and contain 2.5 ppm to 5 ppm (milligrams per
turer’sinstructionsortheASTMspecificationwhenapplicable. litre) of free-chlorine. The chosen pH shall be maintained to
7.4 Minimum Required Test Units—A minimum of six test 60.2 and the chosen free-chlorine concentration shall be
units is required. A test unit is comprised of two or more maintained to 60.2 ppm. The pH and free-chlorine concentra-
individual time-to-failure data points at the same temperature tion combination shall yield a minimum ORP of 825 mV for
and hoop stress condition. Statistical reliability of the analysis the test fluid, see Note 5.
of the resultant data will be benefited by obtaining additional 9.1.2 Tap Water Test Fluid Preparation—Tap water shall
data points at each temperature/hoop stress condition. have a pH in the range from 6.5 to 8.0 and contain the
7.4.1 Test Unit Distribution—Time-to-failure data points necessary free-chlorine to maintain an ORP of 825 6 30 mV,
shall be obtained at 2 test hoop stresses at each of a minimum see Note 5.
of 3 test temperatures for a minimum of 12 data points. As an
NOTE 5—At the time this test method was originally approved, several
alternate, obtain time-to-failure data for the temperature/hoop
test lab
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