ASTM F1948-05(2011)

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An American National Standard
Designation: F1948 – 05 (Reapproved 2011)
Standard Specification for
Metallic Mechanical Fittings for Use on Outside Diameter
Controlled Thermoplastic Gas Distribution Pipe and Tubing
This standard is issued under the fixed designation F1948; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Pipe, Tubing, and Fittings
F412 Terminology Relating to Plastic Piping Systems
1.1 This specification covers requirements and test methods
F1588 Test Method for Constant Tensile Load Joint Test
forthequalificationofmetallicmechanicalfittingsforusewith
(CTLJT)
outside diameter controlled thermoplastic gas distribution pipe
2.2 ASME Standard:
and tubing as specified in Specification D2513.
ASME B 31.8 Gas Transmission and Distribution Piping
1.2 The test methods described are not intended to be
Systems
routine quality control tests.
2.3 Federal Specification:
1.3 Thisspecificationcoversthetypesofmechanicalfittings
OPS Part 192 Title 49, Code of Federal Regulations
described in 3.3.
2.4 Other Document:
1.4 The values stated in inch-pound units are to be regarded
PPI TR-4 Recommended Hydrostatic Strengths and Design
as standard. The values given in parentheses are mathematical
Stresses for Thermoplastic Pipe and Fitting Compounds
conversions to SI units that are provided for information only
and are not considered standard.
3. Terminology
1.5 The following safety hazards caveat pertains only to the
3.1 Definitions are in accordance with Definitions F412
test method portion, Section 7, of this specification. This
unless otherwise specified. Abbreviations are in accordance
standard may involve hazardous material, operations and
with Abbreviations D1600 unless otherwise specified.
equipment. This standard does not purport to address all of the
3.1.1 Thegasindustryterminologyusedinthisspecification
safety concerns, if any, associated with its use. It is the
is in accordance with ASME/ANSI B31.8 or United States
responsibility of the user of this standard to establish appro-
CFR 49 Part 192 unless otherwise indicated.
priate safety and health practices and determine the applica-
3.1.2 The term “pipe” used herein refers to both pipe and
bility of regulatory limitations prior to use.
tubing unless specifically stated otherwise. The term “fitting”
1.6 The text of this standard references notes and footnotes
refers to a mechanical connecting device as described in 3.2.5
which provide explanatory material. These notes and footnotes
and 3.2.7.
(excluding those in tables and figures), shall not be considered
3.2 Definitions:
as requirements of the standard.
3.2.1 Category 1 mechanical fitting, n—fitting for assem-
2. Referenced Documents bling pipe, which includes a compression zone(s) to provide
2 for pressure integrity, leak tightness, and resistance to end
2.1 ASTM Standards:
loads sufficient to cause no less than 25 % elongation of the
D638 Test Method for Tensile Properties of Plastics
piping, as described in this standard.
D1598 Test Method for Time-to-Failure of Plastic Pipe
3.2.2 Category 2 mechanical fitting, n—fitting for assem-
Under Constant Internal Pressure
bling pipe, which includes a compression zone(s) to provide
D1600 Terminology for Abbreviated Terms Relating to
for pressure integrity and leak tightness; Category 2 fittings do
Plastics
not provide for resistance to end loads.
D2513 Specification for Polyethylene (PE) Gas Pressure
3.2.3 Category 3 mechanical fitting, n—fitting for assem-
bling pipe, which includes a compression zone(s) for pressure
This specification is under the jurisdiction ofASTM Committee F17 on Plastic
Piping Systems , and is the direct responsibility of Subcommittee F17.60 on Gas. Available from American Society of Mechanical Engineers (ASME), ASME
Current edition approved Feb. 1, 2011. Published March 2011. Originally International Headquarters, Three Park Ave., New York, NY 10016-5990, http://
published in 1999. Last previous edition approved in 2005 as E1948–05. DOI: www.asme.org.
10.1520/F1948-05R11. Available from the Office of Pipeline Safety, Research and Special Programs
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Administration, U.S. Department of Transportation, 400 Seventh Street, S.W.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Washington, DC, 20006-1301.
Standards volume information, refer to the standard’s Document Summary page on Available from Plastics Pipe Institute (PPI), 105 Decker Court, Suite 825,
the ASTM website. Irving, TX 75062, http://www.plasticpipe.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1948 – 05 (2011)
NOTE 2—Materials should have a demonstrated resistance to environ-
integrity, leak tightness, and resistance to end loads; the
mental stress cracking when exposed, under stress, to chemical com-
nominal size of the fitting shall be 4 and larger in diameter.
pounds encountered in or external to gas piping systems, and a demon-
3.2.3.1 Discussion—Resistance to end loads shall be equal
strated resistance to bacteriological decomposition. Such compounds
to or greater than the maximum thermal stress that would be
include, but are not limited to, ice thawing chemicals, fertilizers, insecti-
produced by a temperature change of 100°F (55°C) (for
cides, herbicides, leak detection fluids, acids, bases and antifreeze
formula, see Annex A1).
solutions used to thaw frozen lines.
3.2.4 joint, n—the location at which two or more pieces of
5. Dimensions
pipe, or a pipe and a fitting, are connected (an installed
coupling has two joints).
5.1 The dimensions and tolerances shall be determined by
3.2.5 joint, mechanical, n—a connection between piping the manufacturer.
components employing physical force to develop a seal or
produce alignment.
6. Qualification Requirements
3.2.6 maximum allowable operating pressure, MAOP,
6.1 General—Unlessotherwisespecified,eachnominalsize
n—of the fuel gas piping system, in psig, as determined in
of fitting shall be tested. Testing the fitting with the thickest
accordance with US DOT CFR, Title 49, Part 192.121, and as
wall pipe for which the fitting is designed qualifies that type of
represented in the following:
fitting for use with pipe of lesser wall thickness.
MAOP5P52 3 S/~R–1!xf (1)
6.1.1 Mechanical joint qualification shall be performed on
assembled joints using the fitting manufacturer’s joining pro-
where:
cedure. All mechanical fittings offered by the manufacturer
S = the pipe material’s HDB as published in PPI TR 4,
shall be capable of meeting the requirements of this standard
R = the pipe’s dimension ratio determined by dividing the
when connecting thermoplastic piping materials complying
pipe’s specified nominal outside diameter by the pipe’s
with Specification D2513. It is not the intent of this standard to
specified nominal wall thickness, and
require the testing of all fitting configurations (that is, tee, ells,
f = design (derating) factor for thermoplastic fuel gas
etc.) but each joint design in each size.
pipingassetbytheauthorityhavingjurisdiction.Inthe
6.1.2 All mechanical fittings described in 3.3 shall have an
United States, the design factor is cited in CFR, Title
internal pipe reinforcing tubular stiffener that extends at least
49, Part 192.121.
under the seal and gripping device (where used).
3.2.7 mechanical fitting, n—fitting for making a mechanical
6.2 Performance Requirements:
joint to provide for pressure integrity, leak tightness, and,
6.2.1 Tensile Strength—The pipe joint shall accommodate
dependingoncategory,asdefinedinthisstandard,resistanceto
the tensile loads, when tested in accordance with 7.2.
end loads.
6.2.1.1 Category 1—The joint shall provide resistance to a
3.3 Types of Mechanical Fittings:
force on the pipe joint equal to or greater than that which will
3.3.1 clamped insert fitting, n—mechanical fitting used to
causenolessthan25 %elongationofthepipe,orwhichcauses
make a mechanical joint that utilizes external clamps, or other
the pipe to fail outside the joint area when tested in accordance
mechanical devices, to form a pressure seal between the
with 7.2.
reinforcing tubular stiffener and the surface of the pipe.
6.2.1.2 Category 2—Joint design that only provides a seal.
3.3.2 compression fitting, n—mechanical fitting used to
A mechanical joint designed for this category excludes any
make a mechanical joint by compressing either externally,
provisions in the design of the joint to resist axial pullout
internally,orradiallytoformapressuresealbetweenthefitting
forces; therefore, tensile tests are not required.
and the surface of the pipe.
6.2.1.3 Category 3—Joint of nominal pipe size 4 and larger
3.3.3 compression gasket fitting, n—mechanical fitting used
in diameter shall provide resistance to a force on the pipe joint
to make a mechanical joint that utilizes a compression nut,
equaltoorgreaterthanthemaximumthermalstressthatwould
tightening ring, bolts, or any other device to compress gasket-
be produced by a temperature change of 100°F (55°C) (for
ing onto the surface of the pipe to form a pressure seal.
formula, see Annex A1).
3.3.4 stab-type fitting, n—mechanical fitting used to make a
mechanical joint in which a seal is achieved by radial com- NOTE 3—Category 3 has a manufacturer’s rated pipe end restraint less
than the value required to yield the pipe as outlined in 6.2.1.1 (Category
pression of a gasket between the outside diameter (OD) of the
1).
pipe and the inside diameter (ID) of the fitting.
6.2.1.4 Joint restraint capabilities less than as defined in
4. Material
6.2.2.1 and 6.2.2.3 shall constitute failure of the test.
4.1 Thephysicalpropertiesofeachmaterialusedtoproduce
6.2.2 Temperature Cycling Test—The mechanicaljointshall
the fitting shall be available from the fitting manufacturer upon
provide a pressure seal after 10 cycles of the temperature
request.
cycling test when tested in accordance with 7.3.
4.2 Specifications outlining the physical and chemical prop-
6.2.3 Constant Tensile Load Test—Thejointshallnotfailby
erties of all fitting materials shall be available from the fitting
leakage or pullout when loaded to an axial tensile stress of
manufacturer upon request.
1320 psi (9101 kPa) and tested in accordance with 7.4.
6.3 Elevated Temperature Sustained Pressure—The fitting,
NOTE 1—Materials in long-term contact with natural gas of line quality
joint or pipe in the area affected by the fitting shall not fail as
and LP
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