ASTM F1948-99a

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1948 – 99a
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 F 1948; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 ASME Standard:
ASME B 31.8 Gas Transmission and Distribution Piping
1.1 This specification covers requirements and test methods
Systems
for the qualification of metallic mechanical fittings for use with
2.3 Federal Specification:
outside diameter controlled thermoplastic gas distribution pipe
OPS Part 192 Title 49, Code of Federal Regulations
and tubing as specified in Specification D 2513.
2.4 Other Document:
1.2 The test methods described are not intended to be
PPI TR-4 Recommended Hydrostatic Strengths and Design
routine quality control tests.
Stresses for Thermoplastic Pipe and Fitting Compounds
1.3 This specification covers the types of mechanical fittings
described in 3.3.
3. Terminology
1.4 The values stated in inch-pound units are to be regarded
3.1 Definitions are in accordance with Definitions F 412
as standard. The values given in parentheses are mathematical
unless otherwise specified. Abbreviations are in accordance
conversions to SI units which are provided for information
with Abbreviations D 1600 unless otherwise specified.
only and not considered standard.
3.1.1 The gas industry terminology used in this specification
1.5 The following safety hazards caveat pertains only to the
is in accordance with ASME/ANSI B31.8 or United States
test method portion, Section 7, of this specification. This
CFR 49 Part 192 unless otherwise indicated.
standard may involve hazardous material, operations and
3.1.2 The term “pipe” used herein refers to both pipe and
equipment. This standard does not purport to address all of the
tubing unless specifically stated otherwise. The term “fitting”
safety concerns, if any, associated with its use. It is the
refers to a mechanical connecting device as described in 3.2.5
responsibility of the user of this standard to establish appro-
and 3.2.7.
priate safety and health practices and determine the applica-
3.2 Definitions:
bility of regulatory limitations prior to use.
3.2.1 Category 1 mechanical fitting, n—fitting for assem-
1.6 The text of this standard references notes and footnotes
bling pipe, which includes a compression zone(s) to provide
which provide explanatory material. These notes and footnotes
for pressure integrity, leak tightness, and resistance to end
(excluding those in tables and figures), shall not be considered
loads sufficient to cause no less than 25 % elongation of the
as requirements of the standard.
piping, as described in this standard.
2. Referenced Documents 3.2.2 Category 2 mechanical fitting, n—fitting for assem-
bling pipe, which includes a compression zone(s) to provide
2.1 ASTM Standards:
for pressure integrity and leak tightness; Category 2 fittings do
D 638 Test Method for Tensile Property of Plastics
not provide for resistance to end loads.
D 1598 Test Methods for Time-To-Failure of Plastic Pipe
3.2.3 Category 3 mechanical fitting, n—fitting for assem-
Under Constant Internal Pressure
2 bling pipe, which includes a compression zone(s) for pressure
D 1600 Abbreviations of Terms Relating to Plastics
integrity, leak tightness, and resistance to end loads; the
D 2513 Specification for Thermoplastic Gas Pressure Pipe,
3 nominal size of the fitting shall be 4 and larger in diameter.
Tubing and Fittings
3.2.3.1 Discussion—Resistance to end loads shall be equal
D 2837 Method for Obtaining Hydrostatic Design Basis for
3 to or greater than the maximum thermal stress that would be
Thermoplastic Pipe Materials
produced by a temperature change of 100°F (55°C) (for
F 412 Definitions of Terms Relating to Plastic Piping Sys-
tems
F 1588 Test Method for Constant Tensile Load Test
Available from the American Society of Mechanical Engineers, Three Park
Ave., New York, NY, 10016-5990.
This specification is under the jurisdiction of ASTM Committee F-17 on Plastic Available from the Office of Pipeline Safety, Research and Special Programs
Piping Systems, and is the direct responsibility of Subcommittee F17.60 on Gas. Administration, U.S. Department of Transportation, 400 Seventh Street, S.W.,
Current edition approved April 10, 1999. Published July 1999. Washington, DC, 20006-1301.
2 6
Annual Book of ASTM Standards, Vol 08.01. Available from the Plastics Pipe Institute, 1801 K Street N.W., Suite 600K,
Annual Book of ASTM Standards, Vol 08.04. Washington, DC, 20006-1301.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1948
solutions used to thaw frozen lines.
formula, see Annex A1).
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
5.1 The dimensions and tolerances shall be determined by
coupling has two joints).
the manufacturer.
3.2.5 joint, mechanical, n—a connection between piping
components employing physical force to develop a seal or
6. Qualification Requirements
produce alignment.
6.1 General—Unless otherwise specified, each nominal size
3.2.6 maximum allowable operating pressure, MAOP,
of fitting shall be tested. Testing the fitting with the thickest
n—of the fuel gas piping system, in psig, as determined in
wall pipe for which the fitting is designed qualifies that type of
accordance with US DOT CFR, Title 49, Part 192.121, and as
fitting for use with pipe of lesser wall thickness.
represented in the following:
6.1.1 Mechanical joint qualification shall be performed on
MAOP5P52 3 S/~R–1!xf (1)
assembled joints using the fitting manufacturer’s joining pro-
cedure. All mechanical fittings offered by the manufacturer
where:
shall be capable of meeting the requirements of this standard
S 5 the pipe material’s HDB as published in PPI TR 4,
when connecting thermoplastic piping materials complying
R 5 the pipe’s dimension ratio determined by dividing the
with Specification D 2513. It is not the intent of this standard
pipe’s specified nominal outside diameter by the pipe’s
to require the testing of all fitting configurations (that is, tee,
specified nominal wall thickness, and
ells, etc.) but each joint design in each size.
f 5 design (derating) factor for thermoplastic fuel gas
6.1.2 All mechanical fittings described in 3.3 shall have an
piping as set by the authority having jurisdiction. In the
internal pipe reinforcing tubular stiffener that extends at least
United States, the design factor is cited in CFR, Title
under the seal and gripping device (where used).
49, Part 192.121.
6.2 Performance Requirements:
3.2.7 mechanical fitting, n—fitting for making a mechanical
6.2.1 Tensile Strength—The pipe joint shall accommodate
joint to provide for pressure integrity, leak tightness, and,
the tensile loads, when tested in accordance with 7.2.
depending on category, as defined in this standard, resistance to
6.2.1.1 Category 1—The joint shall provide resistance to a
end loads.
force on the pipe joint equal to or greater than that which will
3.3 Types of Mechanical Fittings:
cause no less than 25 % elongation of the pipe, or which causes
3.3.1 clamped insert fitting, n—mechanical fitting used to
the pipe to fail outside the joint area when tested in accordance
make a mechanical joint that utilizes external clamps, or other
with 7.2.
mechanical devices, to form a pressure seal between the
6.2.1.2 Category 2—Joint design that only provides a seal.
reinforcing tubular stiffener and the surface of the pipe.
A mechanical joint designed for this category excludes any
3.3.2 compression fitting, n—mechanical fitting used to
provisions in the design of the joint to resist axial pullout
make a mechanical joint by compressing either externally,
forces; therefore, tensile tests are not required.
internally, or radially to form a pressure seal between the fitting
6.2.1.3 Category 3—Joint of nominal pipe size 4 and larger
and the surface of the pipe.
in diameter shall provide resistance to a force on the pipe joint
3.3.3 compression gasket fitting, n—mechanical fitting used
equal to or greater than the maximum thermal stress that would
to make a mechanical joint that utilizes a compression nut,
be produced by a temperature change of 100°F (55°C) (for
tightening ring, bolts, or any other device to compress gasket-
formula, see Annex A1).
ing onto the surface of the pipe to form a pressure seal.
3.3.4 stab-type fitting, n—mechanical fitting used to make a
NOTE 3—Category 3 has a manufacturer’s rated pipe end restraint less
mechanical joint in which a seal is achieved by radial com-
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
6.2.2.1 and 6.2.2.3 shall constitute failure of the test.
4. Material
6.2.2 Temperature Cycling Test—The mechanical joint shall
4.1 The physical properties of each material used to produce
provide a pressure seal after 10 cycles of the temperature
the fitting shall be available from the fitting manufacturer upon
cycling test when tested in accordance with 7.3.
request.
6.2.3 Constant Tensile Load Test—The joint shall not fail by
4.2 Specifications outlining the physical and chemical prop-
leakage or pullout when loaded to an axial tensile stress of
erties of all fitting materials shall be available from the fitting
1320 psi (9101 kPa) and tested in accordance with 7.4.
manufacturer upon request.
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 gas vapor should be demonstrated to not adversely effect the
defined in Test Method D 1598, when tested in accordance
performance of the fitting.
with 7.5. The fitting or joint meets this requirement when tested
NOTE 2—Materials should have a demonstrated resistance to environ-
in accordance with any one of the three conditions (A, B, or C)
mental stress cracking when exposed, under stress, to chemical com-
listed in 7.5.
pounds encountered in or external to gas piping systems, and a demon-
strated resistance to bacteriological decomposition. Such compounds
7. Test Methods
include, but are not limited to, ice thawing chemicals, fertilizers, insecti-
cides, herbicides, leak detection fluids, acids, bases and antifreeze 7.1 General—The test methods in this specification cover
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