ASTM F1734-24

Standard Practice for Qualification of a Combination of Squeeze Tool, Pipe, and Squeeze-Off Procedures to Avoid Long-Term Damage in Polyethylene (PE) Gas Pipe

SIGNIFICANCE AND USE
4.1 This practice relies on a screening process using visual inspection followed by 80 °C sustained pressure testing to qualify a squeeze-off process.  
4.2 Squeeze-off is widely used to temporarily control the flow of gas in PE pipe. Squeeze tools vary in squeeze bar shape and size, operating method, and available stop gaps depending on the tool manufacturer and the size of the pipe the tool will be used on. Multiple squeeze tools are required for a range of pipe size and DR combinations. Squeeze-off procedures can vary depending on the tool design, pipe material, pipe size and DR, pipe operating conditions, and pipe environmental conditions.  
4.3 Experience indicates that damage leading to gas pipe failure is possible with some combinations of polyethylene material, pipe temperature, tool design, wall compression percentage, and procedure. This practice is useful for determining the suitability of a tool for squeeze-off and for determining acceptable limits for squeeze-off such as acceptable minimum and maximum pipe temperature for squeeze and acceptable line pressure for squeeze. Tests conducted at different pipe temperatures with various sizes of tools and pipes can be used to verify a range of temperatures, tool sizes, and pipe sizes for which the squeeze-off procedure is applicable.  
4.4 The area of wrinkling at the ears on the inside diameter (ID) of the pipe and the area on the outside of the pipe opposite the ears are examined. Evidence of any one or a combination of void formation, cracks or extensive localized stress whitening, or failure during sustained pressure testing disqualifies the squeeze-off process.  
4.5 Typical unacceptable features implying long-term damage are shown in Appendix X1 photographs.  
4.6 Studies of polyethylene pipe extruded in the late 1980s (PE2306 and PE3408) show that damage typically does not develop when the wall compression percentage is 30 % or less, when closure rates are 2 in./minute or less and release rates are...
SCOPE
1.1 This practice covers qualifying a combination of a squeeze tool, a polyethylene gas pipe, and a squeeze-off procedure to avoid long-term damage in polyethylene gas pipe. Qualifying is conducted by examining the inside and outside surfaces of pipe specimens at and near the squeeze to determine the existence of features indicative of long-term damage. If indicative features are absent, sustained pressure testing in accordance with Test Method D1598 is conducted to confirm the viability of the squeeze-off process.  
Note 1: This practice may be useful for evaluating the effects of squeeze-off of other piping materials. If applied to other piping materials, research testing to confirm the applicability of this practice to other materials should be conducted.
Note 2: Qualification of historic pipe should follow the historic version of F1734 closest to the pipe manufactured data.  
1.2 This practice is appropriate for any combination of squeeze tool, PE gas pipe, and squeeze-off procedure.  
1.3 This practice is for use by squeeze-tool manufacturers and gas utilities to qualify squeeze tools made in accordance with Test Method F1563; and squeeze-off procedures based on with Guide F1041 with pipe manufactured in accordance with Specification D2513.  
1.4 Governing codes and project specifications should be consulted. Nothing in this practice should be construed as recommending practices or systems at variance with governing codes and project specifications.  
1.5 Where applicable in this practice, “pipe” shall mean “pipe and tubing.”  
1.6 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.7 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 standar...

General Information

• Status: Published
• Publication Date: 31-Mar-2024
• ICS: 23.040.20 - Plastics pipes
• Technical Committee: F17 - Plastic Piping Systems
• Drafting Committee: F17.60 - Gas

Relations

• Replaces: ASTM F1734-19 - Standard Practice for Qualification of a Combination of Squeeze Tool, Pipe, and Squeeze-Off Procedures to Avoid Long-Term Damage in Polyethylene (PE) Gas Pipe
• Effective Date: 01-Apr-2024
• Referred By: ASTM F1041-20 - Standard Guide for Squeeze-Off of Polyolefin Gas Pressure Pipe and Tubing
• Effective Date: 01-Apr-2024

Overview

ASTM F1734-24 is the internationally recognized standard practice developed by ASTM for the qualification of a combination of a squeeze tool, polyethylene (PE) gas pipe, and squeeze-off procedures to avoid long-term damage in PE gas pipe systems. Squeeze-off is a common method for temporarily controlling gas flow by compressing the pipe with a mechanical or hydraulic device. This standard provides a screening process-starting with visual inspection and followed by elevated temperature sustained pressure testing-to ensure that specific tool, pipe, and procedure combinations do not induce features associated with premature pipe failure.

This practice is crucial for both manufacturers and utility operators to verify the suitability of squeeze-off tools and procedures, especially given the range of pipe materials, sizes, and environmental conditions encountered in the field. It helps maintain the integrity and safety of gas distribution systems utilizing PE piping.

Key Topics

• Squeeze-Off Qualification: The standard details a process to qualify a specific combination of squeeze tool, PE pipe, and squeeze-off procedure. Only those combinations that do not produce long-term damage during field operations or visual and pressure tests are acceptable.
• Visual Inspection: After applying the squeeze-off procedure, specimens are inspected visually-both with the unaided eye and under magnification-to identify signs of damage such as cracks, voids, or stress whitening, which are indicators of potential long-term failure.
• Sustained Pressure Testing: If visual inspection passes, further testing is conducted at 80°C using constant internal pressure, simulating demanding field conditions to confirm no delayed failures occur.
• Applicable Range: The practice addresses all combinations of squeeze tool types, PE pipe diameters and thicknesses (Dimension Ratio or DR), environmental and operating conditions, and is especially relevant for older PE materials and large-diameter pipes.
• Criteria for Disqualification: Presence of void formation, cracks, localized whitening, or failures during the pressure test indicates an unsuitable squeeze-off process.

Applications

• For Pipeline Operators and Gas Utilities: The standard offers a reliable method to qualify squeeze-off procedures and tools before field deployment, minimizing risk of long-term pipe damage and ensuring gas distribution safety.
• Tool Manufacturers: Enables tool designers to demonstrate compliance for their squeeze-off products on a wide range of PE pipes by following a recognized qualification process.
• Material and Pipe Manufacturers: Offers a consistent practice for assessing new or historic PE materials, helping to ensure compatibility and safety in gas piping applications.
• Regulatory Compliance: Provides a basis for gas utilities and contractors to meet or exceed codes and project specifications related to gas pipe maintenance and repair.

Related Standards

• ASTM D1598: Test Method for Time-to-Failure of Plastic Pipe Under Constant Internal Pressure-used for sustained pressure testing in this practice.
• ASTM D2513: Specification for Polyethylene (PE) Gas Pressure Pipe, Tubing, and Fittings-defines pipes subject to qualification.
• ASTM D3350: Specification for Polyethylene Plastics Pipe and Fittings Materials.
• ASTM F1041: Guide for Squeeze-Off of Polyolefin Gas Pressure Pipe and Tubing-provides procedural guidance referenced in F1734-24.
• ASTM F1563: Specification for Tools to Squeeze-off Polyethylene (PE) Gas Pipe or Tubing.
• ISO 4437: Plastics piping systems for the supply of gaseous fuels-comparable international requirements.

Practical Value

ASTM F1734-24 improves public safety and system reliability by enabling gas utility operators, tool manufacturers, and pipe suppliers to systematically evaluate the long-term impact of squeeze-off operations on PE gas pipes. It ensures that only well-qualified procedures and equipment are used, helping prevent costly pipeline failures and service disruptions. This standard is integral for anyone engaged in PE gas distribution network maintenance, ensuring compliance with industry best practices and regulatory standards.

Keywords: squeeze-off qualification, polyethylene gas pipe, gas utility safety, sustained pressure testing, squeeze tool compliance, pipeline procedure validation, ASTM standards.

Standards Content (Sample)

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: F1734 − 24 An American National Standard
Standard Practice for
Qualification of a Combination of Squeeze Tool, Pipe, and
Squeeze-Off Procedures to Avoid Long-Term Damage in
Polyethylene (PE) Gas Pipe
This standard is issued under the fixed designation F1734; 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 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This practice covers qualifying a combination of a
responsibility of the user of this standard to establish appro-
squeeze tool, a polyethylene gas pipe, and a squeeze-off
priate safety, health, and environmental practices and deter-
procedure to avoid long-term damage in polyethylene gas pipe.
mine the applicability of regulatory limitations prior to use.
Qualifying is conducted by examining the inside and outside
1.8 This international standard was developed in accor-
surfaces of pipe specimens at and near the squeeze to deter-
dance with internationally recognized principles on standard-
mine the existence of features indicative of long-term damage.
ization established in the Decision on Principles for the
If indicative features are absent, sustained pressure testing in
Development of International Standards, Guides and Recom-
accordance with Test Method D1598 is conducted to confirm
mendations issued by the World Trade Organization Technical
the viability of the squeeze-off process.
Barriers to Trade (TBT) Committee.
NOTE 1—This practice may be useful for evaluating the effects of
squeeze-off of other piping materials. If applied to other piping materials,
2. Referenced Documents
research testing to confirm the applicability of this practice to other
2.1 ASTM Standards:
materials should be conducted.
NOTE 2—Qualification of historic pipe should follow the historic D1598 Test Method for Time-to-Failure of Plastic Pipe
version of F1734 closest to the pipe manufactured data.
Under Constant Internal Pressure
D2122 Test Method for Determining Dimensions of Ther-
1.2 This practice is appropriate for any combination of
moplastic Pipe and Fittings
squeeze tool, PE gas pipe, and squeeze-off procedure.
D2513 Specification for Polyethylene (PE) Gas Pressure
1.3 This practice is for use by squeeze-tool manufacturers
Pipe, Tubing, and Fittings
and gas utilities to qualify squeeze tools made in accordance
F1041 Guide for Squeeze-Off of Polyolefin Gas Pressure
with Test Method F1563; and squeeze-off procedures based on
Pipe and Tubing
with Guide F1041 with pipe manufactured in accordance with
F1563 Specification for Tools to Squeeze-off Polyethylene
Specification D2513.
(PE) Gas Pipe or Tubing
1.4 Governing codes and project specifications should be
2.2 ISO Standards
consulted. Nothing in this practice should be construed as
ISO 4437 Plastics piping systems for the supply of gaseous
recommending practices or systems at variance with governing
fuels
codes and project specifications.
3. Terminology
1.5 Where applicable in this practice, “pipe” shall mean
“pipe and tubing.”
3.1 Definitions:
3.1.1 squeeze-off, n—a technique used to temporarily con-
1.6 Units—The values stated in inch-pound units are to be
trol the flow in a polyethylene pipe by flattening the pipe with
regarded as standard. The values given in parentheses are
a mechanical or hydraulic device.
mathematical conversions to SI units that are provided for
information only and are not considered standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This practice is under the jurisdiction of ASTM Committee F17 on Plastic Standards volume information, refer to the standard’s Document Summary page on
Piping Systems and is the direct responsibility of Subcommittee F17.60 on Gas. the ASTM website.
Current edition approved April 1, 2024. Published May 2024. Originally Available from International Organization for Standardization (ISO), ISO
approved in 1996. Last previous edition approved in 2019 as F1734 – 19. DOI: Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
10.1520/F1734-24. Switzerland, https://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1734 − 24
3.1.1.1 Discussion—Depending on pipe size and wall 4.2 Squeeze-off is widely used to temporarily control the
thickness, stopping flow completely may not be possible. In flow of gas in PE pipe. Squeeze tools vary in squeeze bar shape
some cases, attempting to stop flow may over-compress the and size, operating method, and available stop gaps depending
pipe walls, permanently damage the pipe and lead to premature on the tool manufacturer and the size of the pipe the tool will
failure at the squeeze. Some seepage through the squeeze be used on. Multiple squeeze tools are required for a range of
should be expected especially with larger sizes. pipe size and DR combinations. Squeeze-off procedures can
vary depending on the tool design, pipe material, pipe size and
3.1.2 squeeze process, n—the combination of the squeeze
DR, pipe operating conditions, and pipe environmental condi-
tool, the pipe being squeezed, and the squeeze-off procedure
tions.
being used.
4.3 Experience indicates that damage leading to gas pipe
3.1.3 wall compression (WC), n—the percentage extent to
failure is possible with some combinations of polyethylene
which the pipe walls are compressed when the pipe is
material, pipe temperature, tool design, wall compression
squeezed. (See Fig. 1.) It is defined as:
percentage, and procedure. This practice is useful for deter-
L
mining the suitability of a tool for squeeze-off and for
WC, % 5 1 2 × 100 (1)
S D
2t
determining acceptable limits for squeeze-off such as accept-
where: able minimum and maximum pipe temperature for squeeze and
acceptable line pressure for squeeze. Tests conducted at differ-
L = distance between the squeeze tool bars as shown in Fig.
ent pipe temperatures with various sizes of tools and pipes can
1, and
be used to verify a range of temperatures, tool sizes, and pipe
t = uncompressed pipe wall thickness, expressed in the
sizes for which the squeeze-off procedure is applicable.
same units as L.
4.4 The area of wrinkling at the ears on the inside diameter
3.1.3.1 Discussion—When the distance between the squeeze
(ID) of the pipe and the area on the outside of the pipe opposite
tool bars is greater than twice the wall thickness, the pipe walls
the ears are examined. Evidence of any one or a combination
are not compressed, which yields a negative value for the wall
of void formation, cracks or extensive localized stress
compression percentage. The value becomes positive when the
whitening, or failure during sustained pressure testing disquali-
L value is less than the 2t value. Typical squeeze tool stops are
fies the squeeze-off process.
set for 30 % or less wall compression based on Specification
D2513 maximum wall thickness for pipe size and DR combi-
4.5 Typical unacceptable features implying long-term dam-
nation. This is a distance between the squeeze bars equal to age are shown in Appendix X1 photographs.
70 % of twice the maximum wall thickness for pipe size and
4.6 Studies of polyethylene pipe extruded in the late 1980s
DR combination when the squeeze tool is closed to the stops.
(PE2306 and PE3408) show that damage typically does not
Maximum wall thickness is the minimum wall thickness plus
develop when the wall compression percentage is 30 % or less,
the wall thickness tolerance of 12 %.
when closure rates are 2 in. ⁄minute or less and release rates are
0.5 in. ⁄minute or less, and when squeeze bars have radii 4
4. Significance and Use
times or greater than the pipe maximum wall thickness.
4.1 This practice relies on a screening process using visual
4.7 This practice provides a method to qualify a combina-
inspection followed by 80 °C sustained pressure testing to
tion of squeeze tool, pipe size and material, and squeeze-off
qualify a squeeze-off process.
procedure to ensure that long-term damage does not occur.
This practice is useful for all polyethylene gas pipe, for all pipe
diameters, for new or revised squeeze tool designs, and for new
or revised squeeze-off procedures.
5. Apparatus and Materials
5.1 Squeeze-off Tools, meeting Specification F1563 that are
to be covered by the squeeze-off process.
5.2 Pipe Cutters and Saws, capable of cutting the PE pipe.
5.3 Jeweler’s Loupe or (Stereo) Optical Microscope, pro-
viding 10× or higher magnification.
5.4 Vernier Caliper or Ball-End Micrometer, with an accu-
racy of at least 0.001 in.
5.5 Stopwatch, that can indicate time to at least the nearest
second.
5.6 Sustained pressure testing apparatus in accordance with
Test Method D1598.
5.7 Flow testing apparatus similar to that shown in Fig. 2 or
FIG. 1 Definition of Wall Compression Fig. 3.
F1734 − 24
FIG. 2 Typical Flow Testing Apparatus using Flow Meter for Measurement
FIG. 3 Typical Flow Testing Apparatus using Water Tank and Flask for Measurement
5.8 Polyethylene pipe meeting Specification D2513. 8. Procedure
8.1 Gas Flow Control—Perform an experiment to determine
6. Safety Precautions
the wall compression required to achieve a desired level of
6.1 Care should be taken and appropriate personal protec-
flow control on pipe using the desired tool.
tive equipment used when working with hydraulic and power
tools that may be used in the squeeze-off process. Hearing NOTE 5—Historic research has shown that the shape and size of the
squeeze bar relative to the pipe wall thickness (D/t) influences the amount
protection is recommended when compressed gas is discharged
of flow controlled and the force needed to shut off the flow. For a given
from open-ended specimens.
wall compression level, the equivalent width of the squeeze tool bar must
increase as internal pressure increases and as wall thickness increases to
7. Preparation of the Sample and Equipment
control flow through a squeezed pipe to a given level.
7.1 Select nine pipe samples at least 6 pipe diameters long NOTE 6—In research tests on PE2306 and PE3408 material, a flow of
0.1 ft /h was considered equivalent to stopping flow and wall compression
but not less than 1 ft long.
4,5
over 30% damaged PE3408 material when pipe temperature was -20 °F.
NOTE 3—It is recommended that the thickest wall PE pipe in the
8.1.1 Orient a pipe sample in the flow test apparatus so the
operator’s system that is acceptable for use with the tool of interest be
used for squeeze testing. thickest portion of the pipe wall forms one of the squeeze-off
ears. Locate the squeeze tool at the midpoint of the sample
7.2 Label the samples then measure outside diameter and
length so that the tool is centered on the sample and square to
wall thickness of samples in accordance with Test Method
the centerline of the pipe sample. Closure stops may need to be
D2122. Record wall thickness measurements at 15° increments
removed or smaller stops or shims may be needed to obtain the
around each sample. Identify the location of maximum wall
closure distance required for the desired flow control level.
thickness on each sample.
7.3 Condition samples to the temperature of interest. Expe-
rience with smaller-diameter, lower SDR pipe (for example, 2
Stephens, D. R., Leis, B. N., Francini, R. B., and Cassady, M. J., Volume 1:
to 6-in. SDR 11 pipe) indicates that a minimum of 24 h is
Users’ Guide on Squeeze-Off of Polyethylene Gas Pipes, Topical Report GRI-
required for the sample to reach equilibrium. Thicker wall pipe
92/0147.1, NTIS PB93-161032, Battelle Columbus for Gas Research Institute,
may take longer time to reach thermal equilibrium at the
February 1992.
Stephens, D. R., Leis, B. N., Francini, R. B., and Cassady, M. J., Volume 2:
temperature of interest.
Technical Reference on Squeeze-Off of Polyethylene Gas Pipes, Topical Report
NOTE 4—Several pipe temperatures may need to be investigated to GRI-92/0147.2, NTIS PB93-161040, Battelle Columbus for Gas Researc
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F1734 − 19 F1734 − 24 An American National Standard
Standard Practice for
Qualification of a Combination of Squeeze Tool, Pipe, and
Squeeze-Off Procedures to Avoid Long-Term Damage in
Polyethylene (PE) Gas Pipe
This standard is issued under the fixed designation F1734; 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
1.1 This practice covers qualifying a combination of a squeeze tool, a polyethylene gas pipe, and a squeeze-off procedure to avoid
long-term damage in polyethylene gas pipe. Qualifying is conducted by examining the inside and outside surfaces of pipe
specimens at and near the squeeze to determine the existence of features indicative of long-term damage. If indicative features are
absent, sustained pressure testing in accordance with Specification Test Method D2513D1598 is conducted to confirm the viability
of the squeeze-off process. For assistance with specimen examination, an Adjunct, ADJF1734, is available from ASTM.
NOTE 1—This practice may be useful for evaluating the effects of squeeze-off of other piping materials. If applied to other piping materials, research
testing to confirm the applicability of this practice to other materials should be conducted.
NOTE 2—Qualification of historic pipe should follow the historic version of F1734 closest to the pipe manufactured data.
1.2 This practice is appropriate for any combination of squeeze tool, PE gas pipe and squeeze-off procedure, and is particularly
appropriate for pre-1975 Polyethylene (PE) pipe, and for pipe sizes of 8 in. or above, because of a greater possibility of long-term
damage.pipe, and squeeze-off procedure.
1.3 This practice is for use by squeeze-tool manufacturers, pipe manufacturers and gas utilities to qualify squeeze tools made in
accordance with Specification Test Method F1563; and squeeze-off procedures in accordancebased on with Guide F1041 with pipe
manufactured in accordance with Specification D2513.
1.4 Governing codes and project specifications should be consulted. Nothing in this practice should be construed as recommending
practices or systems at variance with governing codes and project specifications.
1.5 Where applicable in this guide,practice, “pipe” shall mean “pipe and tubing.”
1.6 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.7 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
This practice is under the jurisdiction of ASTM Committee F17 on Plastic Piping Systems and is the direct responsibility of Subcommittee F17.60 on Gas.
Current edition approved Jan. 1, 2019April 1, 2024. Published February 2019May 2024. Originally approved in 1996. Last previous edition approved in 20092019 as
F1734 – 03F1734 – 19.(2009) which was withdrawn April 2018 and reinstated in January 2019. DOI: 10.1520/F1734-19. DOI: 10.1520/F1734-24.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1734 − 24
1.8 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.
2. Referenced Documents
2.1 ASTM Standards:
D1598 Test Method for Time-to-Failure of Plastic Pipe Under Constant Internal Pressure
D2122 Test Method for Determining Dimensions of Thermoplastic Pipe and Fittings
D2513 Specification for Polyethylene (PE) Gas Pressure Pipe, Tubing, and Fittings
D3350 Specification for Polyethylene Plastics Pipe and Fittings Materials
F1041 Guide for Squeeze-Off of Polyolefin Gas Pressure Pipe and Tubing
F1563 Specification for Tools to Squeeze-off Polyethylene (PE) Gas Pipe or Tubing
2.2 ASTM Adjuncts:
Interpretation Aid for Squeeze-Off Damage
2.2 ISO Standards
ISO 4437 Plastics piping systems for the supply of gaseous fuels
3. Terminology
3.1 Definitions:
3.1.1 squeeze-off, n—a technique used to temporarily control the flow of gas in a polyethylene gas pipe by flattening the pipe with
a mechanical or hydraulic device.
3.1.1.1 Discussion—
Depending on pipe size and wall thickness, stopping flow completely may not be possible. In some cases, attempting to stop flow
may over-compress the pipe walls, permanently damage the pipe and lead to premature failure at the squeeze. Some seepage
through the squeeze should be expected especially with larger sizes.
3.1.2 squeeze process, n—the combination of the squeeze tool, the pipe being squeezed, and the squeeze-off procedure being used.
3.1.3 wall compression (WC), n—the percentage extent to which the pipe walls are compressed when the pipe is squeezed. (See
Fig. 1.) It is defined as:
FIG. 1 Definition of Wall Compression
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland,
https://www.iso.org.
F1734 − 24
L
WC, %5 12 ×100 (1)
S D
2t
where:
L = distance between the squeeze tool bars as shown in Fig. 1, and
t = uncompressed pipe wall thickness, expressed in the same units as L.
3.1.3.1 Discussion—
When the distance between the squeeze tool bars is greater than twice the wall thickness, the pipe walls are not compressed, which
yields a negative value for the wall compression percentage. The value becomes positive when the L value is less than the 2t value.
Typical squeeze tool stops are set for 30 % or less wall compression based on Specification D2513 maximum wall thickness (a
distance that is for pipe size and DR combination. This is a distance between the squeeze bars equal to 70 % of twice the maximum
wall thickness for pipe size and DR combination when the squeeze tool is closed to the stops).stops. Maximum wall thickness is
the minimum wall thickness plus the wall thickness tolerance. tolerance of 12 %.
4. Summary of Practice
4.1 Pipe of the size and material of interest is cut into specimens at least 1 ft long or 3 diameters long whichever is greater, and
attached to a supply of pressurized gas. With pressurized gas flowing through the specimen, the specimens are squeezed with the
tool of interest, using the procedure of interest, until the desired level of flow control is achieved. Using Eq 1, the wall compression
percentage at the desired level of flow control is determined. Let this level of wall compression be called WCnom. Additional
specimens are squeezed to obtain squeeze levels that are 5 % greater, 10 % greater, 5 % less and 10 % less than WCnom. This
squeeze range brackets levels of wall compression for flow control.
NOTE 1—For example, if the desired level of flow control were achieved at 25 % wall compression, additional specimens would be prepared at 35 %,
3 4,5
30 %, 20 % and 15 % wall compression. In research tests, a flow of 0.1 ft /h was considered equivalent to stopping the flow.
4.2 The squeezed samples are split along their length at 90 degrees to the squeeze “ears” (See Fig. 1). The area containing the
ears is examined visually using the unaided eye, then magnification. Features such as crazing, small voids, or cracks indicate
permanent damage and disqualify the squeeze-off process.
4.3 Where the results of the visual screening do not indicate permanent damage, additional specimens are squeezed at the WC level
where damage is not indicated, and sustained pressure tests in accordance with Specification D2513 are performed. When sustained
pressure test specimens meet the requirements of Specification D2513, the squeeze-off process has been verified.
4.3.1 When damage is identified at WCnom less 5 % or WCnom less 10 % levels, a wall compression percentage where damage
does not occur should be identified. Prepare additional specimens by lessening wall compression in 5 % increments, and then
examine the specimens to identify a wall compression percentage that does not indicate damage.
NOTE 2—This practice uses flow through the squeezed-off pipe as a parameter. For some combinations of tool, pipe and procedure, it is not possible to
stop flow completely without causing permanent damage to the pipe, particularly for pipes greater than 2 in, nominal size.
4.4 Using a desired squeeze-off procedure, tests conducted at different pipe temperatures with various sizes of tools and pipes can
be used to verify a range of temperatures, tool sizes, and pipe sizes for which the squeeze-off process is applicable.
4. Significance and Use
4.1 This practice relies on a screening process using visual inspection followed by 80 °C sustained pressure testing to qualify a
squeeze-off process.
4.2 Squeeze-off is widely used to temporarily control the flow of gas in PE pipe. Squeeze tools vary in squeeze bar shape and size,
operating method, and available stop gaps depending on the tool manufacturer and the size of the pipe and the design of the tool.
Squeeze-off procedures the tool will be used on. Multiple squeeze tools are required for a range of pipe size and DR combinations.
Squeeze-off procedures can vary depending on the tool design, pipe material, and pipe size and DR, pipe operating conditions, and
pipe environmental conditions.
4.3 Experience indicates that damage leading to gas pipe failure is possible with some combinations of polyethylene material, pipe
F1734 − 24
temperature, tool design, wall compression percentage and procedure can cause damage leading to failure.percentage, and
procedure. This practice is useful for determining the suitability of a tool for squeeze-off and for determining acceptable limits for
squeeze-off such as acceptable minimum and maximum pipe temperature for squeeze and acceptable line pressure for squeeze.
Tests conducted at different pipe temperatures with various sizes of tools and pipes can be used to verify a range of temperatures,
tool sizes, and pipe sizes for which the squeeze-off procedure is applicable.
4.4 The area of wrinkling at the ears on the inside diameter (ID) of the pipe and the area on the outside of the pipe opposite the
ears are examined. Evidence of any one or a combination of void formation, cracks or extensive localized stress whitening, or
failure during sustained pressure testing disqualifies the squeeze-off process.
4.5 Typical unacceptable features implying long-term damage are shown in Appendix X1 photographs.
4.6 Studies of polyethylene pipe extruded in the late 1980s (PE2306 and thereafterPE3408) show that damage typically does not
develop when the wall compression percentage is 30 % or less, when temperatures are aboveclosure rates are 2 in. 50 °F (10 °C),
and when closure and ⁄minute or less and release rates are typical0.5 in. of field conditions for screw-driven tools.⁄minute or less,
With tools meeting Specification F1563, acceptable flow control at typical gas service pressures is achieved at wall compression
,
percentages between 10 and 20 % for pipe diameters less than 6 in.and when Because damage does not develop in these materials
at such squeeze levels, the references cited indicate that squeeze-off flow control practices using tools meeting Specification
squeeze bars have radii 4 times or greater than the F1563 and qualified procedures meeting Practice F1041 are effective for smaller
,
pipe sizes.pipe maximum wall thickness.
NOTE 3—Specification F1563 provides a procedure for evaluating tool flow control performance.
4.7 This practice provides a method to qualify a combination of squeeze tool, pipe size and material, and squeeze-off procedure
to ensure that long-term damage does not occur. This practice is useful for all polyethylene gas pipe manufactured before 1975,
for new or revised polyolefin gas pipe materials, for pipe diameters of 8 in. or above, for pipe, for all pipe diameters, for new or
revised squeeze tool designs, and for new or revised squeeze-off procedures.
6. Interpretation of Results
6.1 This practice relies on a screening process using visual inspection followed by sustained pressure testing as described in
Specification D2513 to qualify a squeeze-off process.
6.2 The area of wrinkling at the ears on the inside diameter (ID) of the pipe and the area on the outside of the pipe opposite the
ears are examined . Evidence of any one or a combination of void formation, cracks or extensive localized stress whitening, or
failure during sustained pressure testing disqualifies the squeeze-off process.
6.3 Unacceptable features implying long-term damage are shown in the photographs in adjunct, ADJF1734 .
5. Apparatus and Materials
5.1 Squeeze-off Tools, meeting Specification F1563 that are to be covered by the squeeze-off process.
5.2 Pipe Cutters and Saws, capable of cutting the PE pipe.
5.3 Jeweler’s Loupe or (Stereo) Optical Microscope, providing 10× or higher magnification.
5.4 Vernier Caliper or Ball-End Micrometer, with an accuracy of at least 0.001 in.
5.5 Stopwatch, that can indicate time to at least the nearest second.
5.6 Sustained pressure testing apparatus in accordance with Test Method D1598.
5.7 Flow testing apparatus similar to that shown in Fig. 2 or Fig. 3.
F1734 − 24
FIG. 2 Typical Flow Testing Apparatus using Flow Meter for Measurement
FIG. 3 Typical Flow Testing Apparatus using Water Tank and Flask for Measurement
5.8 Polyethylene pipe meeting Specification D2513.
8. Materials
8.1 Polyethylene pipe meeting Specification D2513.
6. Safety Precautions
6.1 Care should be taken and appropriate protective equipment for eyes and persons is required personal protective equipment
used when working with hydraulic and power tools that may be used in the squeeze-off process. Personal hearing Hearing
protection is requiredrecommended when compressed gas is discharged from open-ended specimens.
7. Preparation of the Sample and Equipment
7.1 Select nine pipe samples at least 36 pipe diameters long but not less than 1 ft long.
NOTE 3—It is recommended that the thickest wall PE pipe in the operator’s system that is acceptable for use with the tool of interest be used for squeeze
testing.
7.2 Measure the pipe wall thickness Label the samples then measure outside diameter and wall thickness of samples in accordance
with Test Method D2122. Record wall thickness measurements at 15° increments around the pipe, and identify each sample.
Identify the location of maximum wall thickness. thickness on each sample.
7.3 Condition samples to the temperature of interest. Studies show that at very low temperatures or on thicker-walled pipe
significant hold times are necessary to reach thermal equilibrium. Experience with smaller-diameter, lower SDR pipe (for example,
2 to 6-in. SDR 11 pipe) indicates that a minimum of 24 h is required for the sample to reach equilibrium. Thicker wall pipe may
take longer time to reach thermal equilibrium at the temperature of interest.
F1734 − 24
NOTE 4—Several pipe temperatures may need to be investigated to determine the limits for which the squeeze-off procedure is applicable.
8. Procedure
8.1 Gas Flow Control—Orient the sample in the squeeze tool so that the thickest portion of the pipe wall forms one of the
squeeze-off ears. Locate the squeeze tool at the midpoint of the sample length so that the tool is centered on the sample and square
to the centerline of the sample. Perform an experiment to determine the wall compression required to achieve a desired level of
flow control on pipe using the desired tool.
NOTE 5—Historic research has shown that the shape and size of the squeeze bar relative to the pipe wall thickness (D/t) influences the amount of flow
controlled and the force needed to shut off the flow. For a given wall compression level, the equivalent width of the squeeze tool bar must increase as
internal pressure increases and as wall thickness increases to control flow through a squeezed pipe to a given level.
NOTE 6—In research tests on PE2306 and PE3408 material, a flow of 0.1 ft /h was considered equivalent to stopping flow and wall compression over
4,5
30% damaged PE3408 m
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