ASTM F3525/F3525M-21

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F3525/F3525M −21 An American National Standard
Standard Specification
Fabricated Fittings of Crosslinkable Polyethylene (CX-PE)
ThisstandardisissuedunderthefixeddesignationF3525/F3525M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
or tubing create a similar condition.
1. Scope
1.1 This specification establishes requirements for fabri- 1.5 Design of fabricated fittings is outside of the scope of
this standard. Requirements related to thicknesses and taper
cated fittings intended for use with outside-diameter controlled
CX-PE pipe and tubing. These fittings are manufactured by angles are intended to differentiate potentially good, fabricated
fittings from fittings with a high risk of failure. Users of the
heat-fusion joining shape-modified CX-PE components pre-
pared from pipe, molded fittings, sheet, billet, or block. standard are advised that for large or made-to-order fittings,
minimal testing is required by this standard, and it may be
Included are requirements for materials, design, workmanship,
minimum dimensions, marking, test methods, and quality insufficient itself to identify improperly designed and produced
fittings made in accordance with this standard. The design and
control.
production of fittings made in accordance with this standard
1.2 Pressure rating of the fabricated-fitting design is beyond
shall be performed by a fabricator with appropriate training,
the scope of this standard and shall be established by the fitting
equipment and knowledge of fitting design and production.
manufacturer.
1.6 Pipe used to fabricate fittings in accordance with this
1.3 Fittings manufactured in accordance with this specifica-
specification shall be produced in accordance with pipe manu-
tion are primarily intended to be joined to CX-PE pipes and
facturer specifications.
used in CX-PE piping systems that are commissioned in
accordance with a pipe manufacturer recommended commis-
1.7 The text of this specification references notes and
sioning practice. In addition, fittings manufactured in accor-
footnotes which provide explanatory material. These notes and
dance with this specification that are ≥65 % crosslinked prior
footnotes (excluding those in tables and figures) shall not be
to installation can meet the additional requirements of Speci-
considered as requirements of the standard.
fication F2829.
1.8 The values stated in either SI units or inch-pound units
1.4 The pressure rating determined for a fitting will result in
are to be regarded separately as standard. The values stated in
the fittings’ equivalent dimension ratio (EDR). The EDR
each system may not be exact equivalents; therefore, each
specified by the fitting manufacturer is the DR of the piping
system shall be used independently of the other. Non-
system for which the fabricated fitting is intended to be joined.
conformance with this practice is possible if values from the
This standard specifies that fittings be fabricated from pipe
two systems are combined. Values in parentheses are conver-
sections of a lower DR than pipe that the fabricated fitting is
sions that are appropriately rounded for accuracy and preci-
intended to be joined to. This standard follows the pattern of
sion; that are not exact equivalents, and that are for non-
Specification F2206 which specifies that the wall thickness of
mandatory informational purposes.
fabricated multiple segment elbow fittings shall be a minimum
1.9 The following safety hazards caveat pertains only to the
of 22 % more than the pipe to be joined to for example.
pressure test requirements 6.3 of this specification. This stan-
NOTE 1—Increased wall thickness alone is not necessarily sufficient to
dard does not purport to address all of the safety concerns, if
produce fittings adequate for use. Increased wall thickness without
any, associated with its use. It is the responsibility of the user
consideration of proper material placement can be detrimental to perfor-
of this standard to establish appropriate safety, health, and
mance. Finite element analysis studies have shown that abrupt changes in
fitting wall sections, such as between a heavy socket hub and body wall, environmental practices and determine the applicability of
concentrates stress at the transition point. Normal stresses from flex,
regulatory limitations prior to use.
pressure, expansion, and contraction in a plastic piping system can break
1.10 This international standard was developed in accor-
a fitting at this point. Short transitions from 22 % thicker fittings to pipe
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
This specification is under the jurisdiction ofASTM Committee F17 on Plastic
Development of International Standards, Guides and Recom-
Piping Systems and is the direct responsibility of Subcommittee F17.10 on Fittings.
mendations issued by the World Trade Organization Technical
Current edition approved Nov. 1, 2021. Published November 2021. DOI:
10.1520/E3525_F3525M–21 Barriers to Trade (TBT) Committee.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3525/F3525M − 21
2. Referenced Documents crosslinking≥ 65 % it is considered crosslinked pipe. The pipe
2 manufacturer measures the crosslinking level of CX-PE by
2.1 ASTM Standards:
performing a gel content test.
D638 Test Method for Tensile Properties of Plastics
3.2.2 equivalent dimension ratio (EDR), n—the DR of the
D1598 Test Method for Time-to-Failure of Plastic Pipe
pipe to which the fabricated fitting is permitted to be joined.
Under Constant Internal Pressure
3.2.2.1 Discussion—Afabricated fitting made in accordance
D1599 Test Method for Resistance to Short-Time Hydraulic
with this standard will have a thicker wall than the pipe to
Pressure of Plastic Pipe, Tubing, and Fittings
which it is intended to be joined. Fitting ends are to be
D1600 Terminology forAbbreviatedTerms Relating to Plas-
machined so that the fitting end matches the dimensional
tics
specifications of the pipe to which it is to be joined. Greater
D2122 Test Method for Determining Dimensions of Ther-
fitting body thickness is necessary to assure that the fittings
moplastic Pipe and Fittings
have adequate strength in service.
F412 Terminology Relating to Plastic Piping Systems
F2206 Specification for Fabricated Fittings of Butt-Fused
3.2.3 fitting end(s), n—the end(s) of the fabricated fitting
Polyethylene (PE)
intended for field joining by the installer.
F2829 Specification for Metric- and Inch-Sized Fittings for
3.2.4 fabricated fitting, n—a fitting constructed from manu-
Crosslinked Polyethylene (PEX) Pipe
factured CX-PE components or materials.
F2880 Specification for Lap-Joint Type Flange Adapters for
PolyethylenePressurePipeinNominalPipeSizes ⁄4in.to
4. Ordering Information
65 in.
4.1 When ordering fittings under this specification include
F2928 Practice for Specimens and Testing Conditions for
the following information:
Testing Polyethylene (PE) Pipe Butt Fusions Using Ten-
4.1.1 CX-PE compound (material designation or trade
sile and Hydrostatic Test Methods
name). The material designation shall match the pipe that the
F3183 Practice for Guided Side Bend Evaluation of Poly-
fabricated fitting is intended to be joined to.
ethylene Pipe Butt Fusion Joint
4.1.2 Style of fitting (for example: 3-piece tee, 5-segment
F3203 Test Method for Determination of Gel Content of
90° ell, etc.).
Crosslinked Polyethylene (PEX) Pipes and Tubing
4.1.3 Size:
F3507 Practice for Butt-Fusion Joining of Crosslinkable
4.1.3.1 Nominal size of end connections.
Polyethylene (CX-PE) Pipe and Tubing
4.1.3.2 End configurations (for example, metric or inch,
2.2 Other Standards:
socket, or flange).
AWWA C906-15 Polyethylene (PE) Pressure Pipe and
4.1.3.3 System DR.
Fittings, 4 in. Through 65 in. (100 mm Through 1650
mm), for Waterworks
5. Material
FED-STD 123G Marking for Shipment (Civil Agencies)
5.1 CX-PE materials allowed for use in fittings produced in
Military Standard 129P Military Marking for Shipment and
accordance with this specification shall be in accordance with
Storage
the manufacturer’s fabricated-fitting design specifications.
3. Terminology
5.2 CX-PE pipe used in the production of fittings in accor-
3.1 Definitions and abbreviations used are in accordance
dance with this specification shall meet the requirements of the
with Terminology F412 and with Terminology D1600, unless
applicable CX-PE pipe specification.
otherwise specified.
5.3 Flange adaptors used in the production of fabricated
3.2 Definitions:
fittings in accordance with this specification shall meet pur-
3.2.1 crosslinkable polyethylene, (CX-PE), n—polyethylene
chaser requirements.
compound that has been chemically modified so that crosslinks
NOTE 2—Dimensions of CX-PE flange adapters should be in accor-
will form when the compound is exposed to heat and moisture
dance with Specification F2880. A CX-PE flange adaptor specification
at the same time, with the possibility of the final crosslinking
using dimensions and tolerances like those specified in Specification
taking place after installation of pipe made from CX-PE
F2880 is expected to be developed later.
compound.
5.4 Sheet, block or plate stock used in the production of
3.2.1.1 Discussion—CX-PE pipe is minimally crosslinked
fabricated fittings shall be produced from the same material
and is best butt fused before the level of crosslinking reaches
designation of CX-PE compound. (See 4.1.1.)
30 %. When pipe made from CX-PE reaches a level of
NOTE 3—Manufacturers should use appropriate quality assurance
procedures to ensure that sheet, block, and plate are free from voids,
laminations, foreign inclusions, cracks, and other injurious defects.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Manufacturers should also store all CX-PE pipe, sheet, block, or plate
Standards volume information, refer to the standard’s Document Summary page on stock in as cool and dry a location as possible before fabrication. Storage
the ASTM website.
should be for a minimal amount of time and should avoid exposure to UV
Available fromAmerican Water WorksAssociation (AWWA), 6666 W. Quincy
weathering.
Ave., Denver, CO 80235, http://www.awwa.org.
5.5 CX-PE pipe, sheet, block, or plate stock used to fabri-
Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
Philadelphia, PA 19111-5094, http://quicksearch.dla.mil. cate fittings per this specification shall have been produced
F3525/F3525M − 21
within less than six months prior to the date they are used for the tapers shall be offset by at least the wall thickness of the
fabrication. Alternatively, documented testing shall be per- pipe intended to be joined to.
formed to demonstrate that the pipe sheet, block, or plate stock
NOTE 4—The counterboring and outside tapering of the fitting ends to
used to fabricate fittings is crosslinked to <30 % when tested in
match the specified diameter and wall thickness of the pipe the fitting is
accordance with Test Method F3203 prior to fabrication.
intended to be joined to should be carefully designed. Generous radius
Follow Annex A1 which provides additional requirements for fillets should be used. The intent is to minimize stress concentration due
to differential strain on different parts of the fitting circumference.
suitable storage and testing of storage life.
6.2.3 Fabrication of complex fittings or made-to-order fit-
6. Requirements
tings that are combinations of elbows, tees and wyes are
permitted, but require engineering consideration of the stresses
6.1 Dimension and Tolerances—Fitting ends shall be ma-
on the individual joints making up the fitting and the combi-
chined to meet the diameter and wall thickness requirements of
nation of the joints together. For example, a cross fitting will
the pipe to which joining is intended.
require wall thickness reinforcement beyond that required for a
6.1.1 Diameter—The outside diameters and diameter toler-
tee fitting to achieve the same pressure rating.
ances for fitting ends made in accordance with this standard
specification shall be the same as specified in approved NOTE 5—Specification F2206 which is applicable to production of PE
fabricated fittings has similar minimum thickness requirements. CX-PE
specifications for CX-PE pipe in metric and inch sizes for the
fittings being substantially identical to PE fittings with the exception that
specified nominal pipe size and DR. In the absence of an
theyareexpectedtobecrosslinkedafterinstallationarethereforedesigned
applicable pipe specification the diameter tolerance shall be a
similarly. The wall thickness requirement of this specification is a
minimum 6 0.5 %oftheaveragediameterofthepipeintended
minimum only and does not prohibit fittings from being fabricated from
to be joined to. thicker wall stock or from being otherwise reinforced to meet other
requirements either of this specification or resulting from anticipated uses
6.1.2 Wall Thickness—The minimum wall thickness of fit-
of fabricated fittings.
ting ends made in accordance with this specification shall be
6.3 Pressure Test Requirements—Tests in accordance with
the same as specified for the CX-PE pipe the fittings are
6.3.2 and 6.3.3 need only be conducted on representative test
intended to be used with. This is permitted to be achieved by
samples of each style of fitting for diameters up to and
beveling either the inside or outside or both edges to transition
including 12 in. (300 mm) diameter. Alternatively, if made-to-
from the thicker wall thickness of the fitting specified in 7.2 to
order or larger than 12 in. (300 mm) diameter fittings are
the wall thickness of the pipe that the fitting is intended to be
produced, testing shall be in accordance with 6.3.4 only.
joined to. Allowance shall be made for facing and bead
roll-back when the fitting is butt-fused to pipe in the field. 6.3.1 Asingle EDR sample shall be considered as represen-
tative of all the wall thicknesses produced in that style
6.1.3 Eccentricity—The wall thickness variability of the
grouping. The EDR and diameter of the test fittings shall be in
fitting end as measured and calculated in accordance with Test
the mid-range of the wall thicknesses and diameters typically
Method D2122, in any diametrical cross-section of the pipe
produced for that fitting style. Fitting styles are characterized
shall not exceed 12 %.
as elbows, tees, wyes, crosses, reducing tees, reducing laterals,
6.1.4 Laying Lengths—Laying length dimensions shall be
branch saddles, mechanical joint adapters, and end caps.
defined by the manufacturer.
6.3.2 Elevated Temperature Sustained Pressure Test—Test
6.2 Physical Requirements—Fabricated straight reducer
three specimens per fitting style in accordance with 8.4.2. Each
couplings do not require thicker walls but shall be fabricated
specimen shall have a minimum distance of three pipe diam-
from sufficiently heavy wall stock to permit tapering in
eters between end closures and any miter joints in the fittings.
accordance with 6.2.2. Fabricated fittings using miter cut pipe
This test need only be performed for the initial qualification of
stock shall be manufactured from pipe stock with a wall
a fitting style using a particular CX-PE compound.
thickness that is at least 22 % greater than that of the pipe to
NOTE6—Theelevatedtemperaturesustainedpressuretestisintendedto
which the fitting is to be joined. (For example:An EDR11 five
simulate that process of crosslinking of the fitting, but with a higher
gore elbow fitting shall be made using DR9 pipe stock.)
pressure. During crosslinking fittings made from CX-PE are most vulner-
Fabricated tee fittings shall be manufactured from pipe stock
able to failure as a result of any stress concentration points in the design
with a wall thickness that is at least 50 % greater than that of
of the fitting. This is not intended to be a test of fusion joint strength but
the pipe to which the fitting is to be joined. Fabricated wyes a test of the suitability of the fitting design with the CX-PE compound
used.
shall be manufactured from pipe stock with a wall thickness
that is at least 150 % greater than that of the pipe to which the
6.3.3 Short-term Pressure Testing—Test five specimens per
fitting is to be joined.
fittingstyleinaccordancewith8.4.3.Eachspecimenshallhave
6.2.1 For the fabrication of fittings requiring a heavier wall
...