ASTM D2671-21

Standard Test Methods for Heat-Shrinkable Tubing for Electrical Use

SIGNIFICANCE AND USE
4.1 These test methods include most of the important tests used to characterize heat-shrinkable tubing. They are intended primarily for, but not limited to, extruded heat-shrinkable tubing.  
4.2 It is acceptable to use variations in these test methods or alternate contemporary methods of measurement to determine the values for the properties in this standard provided such methods ensure quality levels and measurement accuracy equal to or better than those prescribed herein. It is the responsibility of the organizations using alternate test methods to be able to demonstrate this condition. In cases of dispute, the methods specified herein shall be used.
Note 2: Provision for alternate methods is necessary because of (1) the desire to simplify procedures for specific applications without altering the result, and (2) the desire to eliminate redundant testing and use data generated during manufacturing process control, including that generated under Statistical Process Control (SPC) conditions, using equipment and methods other than those specified herein. An example would be the use of laser micrometers or optical comparators to measure dimensions.
SCOPE
1.1 These test methods cover the testing of heat-shrinkable tubing used for electrical insulation. Materials used include poly(vinyl chloride), polyolefins, fluorocarbon polymers, silicone rubber, and other plastic or elastomeric compounds.  
1.2 These test methods appear in the following sections:    
Procedure  
Section(s)  
Test
Method(s)  
Adhesive Peel Strength  
94 – 100  
Brittleness Temperature  
40  
D746  
Color  
55 and 56  
D1535  
Color Stability  
57 – 62  
D1535  
Conditioning  
7  
D618  
Copper Stability  
89  
Corrosion Testing  
85 – 91  
Dielectric Breakdown  
20 – 25  
D149  
Dimensions  
8 – 13  
D876  
Flammability  
68  
D8355
(Methods A, C, or D)  
Fluid Resistance  
63 – 67  
Fungus Resistance  
100 – 104  
Heat Resistance  
49 – 54  
Heat Shock  
26 – 30  
Low-temperature Properties  
36 – 43  
Restricted Shrinkage  
14 – 19  
Selection of Test Specimens  
6  
Secant Modulus  
77 – 80  
D882  
Storage Life  
31 – 35  
Specific Gravity  
69 and 70  
D792  
Stress Modulus  
81 – 84  
D412  
Tensile Strength and Ultimate Elongation  
44 – 48  
D412  
Thermal Endurance  
92 and 93  
Volume Resistivity  
71 – 74  
D257  
Water Absorption  
75 and 76  
D570  
Melting Point  
100 – 104  
D3418  
1.3 The values stated in inch-pound units are to be regarded as standard, except for temperature, which shall be expressed in degrees Celsius. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.4 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. For specific hazard statements, see Section 5 and for fire test safety caveats see Test Methods D8355.
Note 1: These test methods are similar, but not identical to, those in IEC 60684-2 (see also Note 9).  
1.5 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.

General Information

• Status: Published
• Publication Date: 31-Dec-2020
• ICS: 29.120.99 - Other electrical accessories
• Technical Committee: D09 - Electrical and Electronic Insulating Materials
• Drafting Committee: D09.07 - Electrical Insulating Materials

Relations

• Refers: ASTM D1711-24 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Mar-2024
• Refers: ASTM E176-24 - Standard Terminology of Fire Standards
• Effective Date: 01-Jan-2024
• Refers: ASTM D149-20 - Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies
• Effective Date: 01-Jan-2020
• Refers: ASTM E176-18a - Standard Terminology of Fire Standards
• Effective Date: 15-Dec-2018
• Refers: ASTM E176-18 - Standard Terminology of Fire Standards
• Effective Date: 01-Mar-2018
• Refers: ASTM D1711-15 - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Nov-2015
• Refers: ASTM E176-15a - Standard Terminology of Fire Standards
• Effective Date: 01-Aug-2015
• Refers: ASTM E176-15ae1 - Standard Terminology of Fire Standards
• Effective Date: 01-Aug-2015
• Refers: ASTM E176-15 - Standard Terminology of Fire Standards
• Effective Date: 01-Feb-2015
• Refers: ASTM D1711-14a - Standard Terminology Relating to Electrical Insulation
• Effective Date: 01-Nov-2014
• Refers: ASTM D1535-14 - Standard Practice for Specifying Color by the Munsell System
• Effective Date: 01-Nov-2014
• Refers: ASTM E176-14c - Standard Terminology of Fire Standards
• Effective Date: 01-Oct-2014
• Refers: ASTM E176-14b - Standard Terminology of Fire Standards
• Effective Date: 15-Aug-2014
• Refers: ASTM E176-14a - Standard Terminology of Fire Standards
• Effective Date: 01-Aug-2014
• Refers: ASTM E176-14 - Standard Terminology of Fire Standards
• Effective Date: 01-Jul-2014

Overview

ASTM D2671-21: Standard Test Methods for Heat-Shrinkable Tubing for Electrical Use establishes test procedures for evaluating the performance and reliability of heat-shrinkable tubing designed for electrical insulation. This standard, developed by ASTM International, applies primarily to extruded heat-shrinkable tubing made from poly(vinyl chloride), polyolefins, fluorocarbon polymers, silicone rubber, and other plastic or elastomeric materials used in electrical applications. By outlining standardized methods for testing important physical, electrical, and mechanical properties, this ASTM standard ensures consistent quality and performance for materials used in critical electrical insulation tasks.

Key Topics

ASTM D2671-21 covers a comprehensive range of test methods, addressing core characteristics of heat-shrinkable electrical tubing:

• Physical properties:

  • Inside diameter and wall thickness measurement in expanded and recovered states
  • Concentricity, longitudinal change, and storage life determination
  • Color, color stability, and dimensional assessments

• Mechanical properties:

  • Tensile strength, ultimate elongation, and secant modulus
  • Heat resistance and heat shock response
  • Low-temperature flexibility, brittleness temperature, and restricted shrinkage

• Electrical properties:

  • Dielectric breakdown voltage and dielectric strength
  • Volume resistivity

• Chemical properties:

  • Fluid resistance and specific gravity
  • Fungus resistance, copper stability, and corrosion resistance
  • Water absorption and thermal endurance

• Other performance factors:

  • Flammability testing for fire-safety assurance
  • Adhesive peel strength (for tubing with adhesives)
  • Evaluation of melting point

The standard acknowledges contemporary measurement alternatives, such as the use of laser micrometers or optical comparators, provided quality and accuracy are maintained.

Applications

The robust test methods detailed in ASTM D2671-21 are vital for industries where electrical insulation is critical. Key applications include:

• Electrical and electronics manufacturing: Ensuring heat-shrinkable tubing meets precise requirements for insulation, protection, and wire management in assemblies and finished products.
• Automotive and transportation: Testing tubing used for harnesses, connectors, and components subject to harsh environments, temperature extremes, and mechanical stress.
• Aerospace and defense: Supporting the use of heat-shrinkable tubing in mission-critical electronic and avionic systems, where reliability and safety are paramount.
• Telecommunications: Verifying protection of cables, splices, and fiber-optic components against environmental and electrical hazards.
• General industrial use: Safeguarding electrical joints, terminations, and repairs in installation and maintenance.

By employing these standardized test methods, manufacturers and end-users can benchmark product quality, comply with procurement specifications, and demonstrate adherence to industry best practices.

Related Standards

ASTM D2671-21 references additional standards and harmonizes with international guidelines to promote compatibility and quality assurance:

• ASTM referenced methods:

  • ASTM D149 (dielectric strength)
  • ASTM D257 (volume resistivity)
  • ASTM D412 (tension tests for rubber and thermoplastics)
  • ASTM D570 (water absorption)
  • ASTM D618 (conditioning plastics for testing)
  • ASTM D792 (specific gravity)
  • ASTM D8355 (flammability methods)

• International and military standards:

  • IEC 60684-2 (Flexible Insulating Sleeving Test Methods)
  • MIL-STD-104 (Limits for Electrical Insulation Color)
  • ISO 846 (Evaluation of the action of microorganisms on plastics)

Aligning with recognized global standardization principles, ASTM D2671-21 supports compliance in international markets and meets regulatory requirements in sectors governed by the World Trade Organization Technical Barriers to Trade (TBT) guidelines.

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Keywords: ASTM D2671, heat-shrinkable tubing test, electrical insulation standard, test methods, dielectric strength, flammability testing, industrial wire insulation, tubing quality testing, electrical product safety, international standards, polymer tubing testing.

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: D2671 − 21
Standard Test Methods for
Heat-Shrinkable Tubing for Electrical Use
This standard is issued under the fixed designation D2671; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 These test methods cover the testing of heat-shrinkable
mine the applicability of regulatory limitations prior to use.
tubing used for electrical insulation. Materials used include
For specific hazard statements, see Section 5 and for fire test
poly(vinyl chloride), polyolefins, fluorocarbon polymers, sili-
safety caveats see Test Methods D8355.
cone rubber, and other plastic or elastomeric compounds.
NOTE 1—These test methods are similar, but not identical to, those in
1.2 These test methods appear in the following sections:
IEC 60684-2 (see also Note 9).
Test
Procedure Section(s)
1.5 This international standard was developed in accor-
Method(s)
Adhesive Peel Strength 94 – 100
dance with internationally recognized principles on standard-
Brittleness Temperature 40 D746
ization established in the Decision on Principles for the
Color 55 and 56 D1535
Development of International Standards, Guides and Recom-
Color Stability 57 – 62 D1535
Conditioning 7 D618
mendations issued by the World Trade Organization Technical
Copper Stability 89
Barriers to Trade (TBT) Committee.
Corrosion Testing 85–91
Dielectric Breakdown 20 – 25 D149
Dimensions 8 – 13 D876
2. Referenced Documents
Flammability 68 D8355
(Methods A, C, 2.1 ASTM Standards:
or D)
D149 Test Method for Dielectric Breakdown Voltage and
Fluid Resistance 63–67
DielectricStrengthofSolidElectricalInsulatingMaterials
Fungus Resistance 100 – 104
at Commercial Power Frequencies
Heat Resistance 49–54
Heat Shock 26–30
D257 Test Methods for DC Resistance or Conductance of
Low-temperature Properties 36–43
Insulating Materials
Restricted Shrinkage 14–19
Selection of Test Specimens 6 D412 Test Methods forVulcanized Rubber andThermoplas-
Secant Modulus 77 – 80 D882
tic Elastomers—Tension
Storage Life 31–35
D570 Test Method for Water Absorption of Plastics
Specific Gravity 69 and 70 D792
Stress Modulus 81 – 84 D412 D618 Practice for Conditioning Plastics for Testing
Tensile Strength and Ultimate Elongation 44 – 48 D412
D746 Test Method for Brittleness Temperature of Plastics
Thermal Endurance 92 and 93
and Elastomers by Impact
Volume Resistivity 71 – 74 D257
Water Absorption 75 and 76 D570
D792 Test Methods for Density and Specific Gravity (Rela-
Melting Point 100 – 104 D3418
tive Density) of Plastics by Displacement
1.3 The values stated in inch-pound units are to be regarded
D876 Test Methods for Nonrigid Vinyl Chloride Polymer
as standard, except for temperature, which shall be expressed
Tubing Used for Electrical Insulation
in degrees Celsius. The values given in parentheses are
D882 Test Method for Tensile Properties of Thin Plastic
mathematical conversions to SI units that are provided for
Sheeting
information only and are not considered standard.
D1535 Practice for Specifying Color by the Munsell System
D1711 Terminology Relating to Electrical Insulation
1.4 This standard does not purport to address all of the
D3418 Test Method for Transition Temperatures and En-
safety concerns, if any, associated with its use. It is the
thalpies of Fusion and Crystallization of Polymers by
These test methods are under the jurisdiction of ASTM Committee D09 on
Electrical and Electronic Insulating Materials and are the direct responsibility of
Subcommittee D09.07 on Electrical Insulating Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2021. Published February 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1967. Last previous edition approved in 2013 as D2671 – 13. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D2671-21. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2671 − 21
Differential Scanning Calorimetry 4. Significance and Use
E176 Terminology of Fire Standards
4.1 These test methods include most of the important tests
D8355 Test Methods for Flammability of Electrical Insulat-
used to characterize heat-shrinkable tubing. They are intended
ing Materials Used for Sleeving or Tubing
primarily for, but not limited to, extruded heat-shrinkable
tubing.
2.2 IEC Standards:
IEC 216 Guide for the Determination of Thermal Endurance
4.2 It is acceptable to use variations in these test methods or
Properties of Electrical Insulating Materials
alternate contemporary methods of measurement to determine
IEC 60684 Specification for Flexible Insulating Sleeving
the values for the properties in this standard provided such
methodsensurequalitylevelsandmeasurementaccuracyequal
2.3 Military Standard:
to or better than those prescribed herein. It is the responsibility
MIL-STD-104 Limits for Electrical Insulation Color
of the organizations using alternate test methods to be able to
2.4 ISO Standard:
demonstrate this condition. In cases of dispute, the methods
ISO 846 Plastics—Evaluation of the Action of Microorgan-
specified herein shall be used.
isms
NOTE2—Provisionforalternatemethodsisnecessarybecauseof(1)the
desire to simplify procedures for specific applications without altering the
3. Terminology
result, and (2) the desire to eliminate redundant testing and use data
generated during manufacturing process control, including that generated
3.1 Definitions:
under Statistical Process Control (SPC) conditions, using equipment and
3.1.1 For definitions pertaining to electrical insulation, refer
methods other than those specified herein. An example would be the use
to Terminology D1711.
of laser micrometers or optical comparators to measure dimensions.
3.1.2 For definitions pertaining to fire standards, refer to
5. Hazards
Terminology E176.
5.1 (Warning—Lethal voltages are potentially present dur-
3.1.3 heat-shrinkable tubing, n—tubing that will reduce in
ing this test. It is essential that the test apparatus, and all
diameter from an expanded size to a predetermined size by the
associated equipment that is potentially electrically connected
application of heat.
to it, be properly designed and installed for safe operation.
3.2 Definitions of Terms Specific to This Standard: Solidly ground all electrically conductive parts that any person
might come in contact with during the test. Provide means for
3.2.1 brittleness temperature, n—the temperature at which
use at the completion of any test to ground any parts which: (a)
50 % of the specimens fail when the specified number are
were at high voltage during the test, (b) have potentially
tested using the apparatus and conditions specified.
acquired an induced charge during the test, or (c) could have
3.2.2 concentricity, n—the ratio expressed in percent of the
retained a charge even after disconnection of the voltage
minimum wall thickness to the maximum wall thickness.
source. Thoroughly instruct all operators in the proper way to
conduct tests safely. When making high voltage tests, particu-
3.2.3 longitudinal change, n—the change in length, either
larly in compressed gas or in oil, it is possible that the energy
positive or negative, that occurs when the tubing is allowed to
released at breakdown would be sufficient to result in fire,
freely recover at the recommended recovery temperature,
explosion, or rupture of the test chamber. Design test
expressed as a percentage of the as supplied or expanded
equipment,testchambers,andtestspecimenssoastominimize
length.
the possibility of such occurrences and to eliminate the
3.2.4 low-temperature flexibility, n—the resistance to crack-
possibility of personal injury. See Section 23.)
ing of tubing when wrapped around prescribed mandrels at
5.2 Flammable Solvents:
specified temperatures.
5.2.1 Methylethylketoneisavolatile,flammablesolvent.It
3.2.5 restricted shrinkage, n—shrinkage of the tubing at a
shall be handled in an area having good ventilation, such as a
prescribed temperature over a specially designed mandrel
laboratory hood and away from sources of ignition. See
whose smallest diameter is greater than the fully shrunk size
Section 96.
andwhoselargestdiameterislessthantheexpandedsizeofthe
6. Selection of Test Specimens
tubing.
6.1 Select a sufficient number of pieces of tubing in such
3.2.6 storage-life, heat-shrinkable tubing, n—the length of
manner as to be representative of the shipment.
time that the tubing will retain its specified expanded and
6.2 Cut specimens, free of kinks, from the sample selected
recovered dimensions under storage at a specified temperature.
under 6.1. Cut perpendicular to the longitudinal axis of the
tubing and in such manner that the specimen has cleanly cut
square edges.
Available from International Electrotechnical Commission (IEC), 3, rue de
6.3 Unless otherwise stated, conduct tests on specimens in
Varembé, 1st floor, P.O. Box 131, CH-1211, Geneva 20, Switzerland, https://
www.iec.ch.
the completely shrunk condition.
Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
7. Conditioning
Available from International Organization for Standardization (ISO), ISO
7.1 When specified, condition tubing in accordance with
Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, https://www.iso.org. Practice D618 using Procedure A, except that a conditioning
D2671 − 21
time of 4 h shall be used. In cases where tests are performed on effected without restriction. If the tubing tends to become
specimens in the shrunk state, condition the test specimens sticky at the shrinkage temperature, specimens can be laid in
prior to testing, but after heat shrinking. trays that have been powdered slightly with talc.
11.1.4 At the end of the specified shrinkage time, remove
DIMENSIONS
the specimens from the oven and allow to cool to room
temperature. Measure the inside diameter as described in
8. Significance and Use
11.1.1 and 11.1.2, recording this as the recovered inside
8.1 Inside Diameter—The inside diameter of tubing before
diameter.
and after heat-shrinking is an important factor in selecting
11.2 Measuring Wall Thickness:
tubing of the proper size to slip easily over an object and to
11.2.1 Measure the wall thickness of the expanded (as
conform tightly after shrinkage.
supplied) tubing using a micrometer. By means of a sufficient
8.2 Wall Thickness—Wall thickness measurements are use-
number of tests, locate the points on the wall corresponding to
ful in providing design data and in calculating certain physical the minimum and the maximum wall thickness, and record
and electrical properties of the tubing.
these measurements to the nearest 0.001 in. (0.02 mm).
11.2.2 Allow the specimens to recover under heat as de-
8.3 Concentricity—In some cases, a thin wall area, due to
scribed in 11.1.3 and 11.1.4. Measure the wall thickness as
variation in processing, will lead to equipment failure. It is
described in 11.2.1 recording these as the recovered thick-
important, therefore, both in extrusion of the tubing, and its
nesses.
expansion prior to shrinkage in end-use, that concentricity be
held above a specified limit to ensure proper performance of
11.3 Calculating Concentricity—From measurements of
the tubing.
minimum and maximum wall thickness made in accordance
with 11.2.1 and 11.2.2, calculate the concentricity (C) of the
8.4 Length—The length, both before and after heat-
expanded and recovered tubing respectively, using the follow-
shrinking, is important in the determination of proper fit of the
ing equation:
tubing in end-use.
C 5 100 M"/M' (1)
~ !
9. Apparatus
where:
9.1 Mandrels—Use a series of steel rods suitable for inser-
M' = maximum thickness, in. (mm), and
tionintothetubingincludingthetaperedgagesdescribedunder
M" = minimum thickness, in. (mm).
Test Methods D876.
11.4 Measuring Length:
9.2 Micrometers, mandrel anvil and indicator set accurate to
11.4.1 Using the steel scale, measure the length to the
at least 0.001 in. or 0.02 mm.
nearest ⁄32 in. or 1 mm.
9.3 Steel Scale, graduated in ⁄64-in. or 0.5 mm divisions.
11.4.2 Allow the specimens to recover under heat as de-
scribed in 11.1.3 and 11.1.4. Measure the length after recovery.
9.4 Oven, forced-convection type, capable of maintaining
Record the length in the expanded and recovered state.
temperature to within 65 °C.
11.5 Calculating Longitudinal Change—From the measure-
10. Test Specimens
ments of expanded and recovered length made in accordance
with 11.4.1 and 11.4.2, calculate the percent longitudinal
10.1 Cut three straight lengths of expanded tubing, each 6
change using the following equation:
in. (150 mm) long, from the sample as directed in 6.2 for each
test performed.
percent longitudinal change 5 100 L'2L" /L" (2)
~ !
where:
11. Procedure
L' = recovered length, in. (mm), and
11.1 Measuring Inside Diameter:
L" = expanded length, in. (mm).
11.1.1 Select a mandrel that will just fit into the specimen
and insert the mandrel into the expanded tubing for a distance
12. Report
of 1 in. (25 mm).
12.1 Report the following information:
NOTE 3—If the tubing specimens have a tendency to adhere to the
12.1.1 Identification of the tubing,
mandrels during measurement of diameter, it is recommended that the
12.1.2 Inside diameter of the tubing in the expanded and in
mandrels be coated with water or talc as a lubricant. However, caution
must be exercised not to force the tubing on the mandrel, thereby
the recovered state,
stretching the specimens.
12.1.3 Maximum and minimum wall thickness for each
11.1.2 Using a machinist’s micrometer, measure the outside specimen in the expanded and in the recovered state,
12.1.4 Length of each specimen in the expanded and recov-
diameter of the mandrel to the nearest 0.001 in. (0.02 mm).
Record this as the expanded inside diameter. ered state,
12.1.5 Percentage longitudinal change of each specimen
11.1.3 Place the specimen in an oven at the temperature
specifiedassuitableforcompleteshrinkageforaperiodoftime (after recovery) based on the expanded state length,
recommended for shrinkage. Make provision for positioning 12.1.6 Concentricity of each specimen in the expanded and
the specimen horizontally in the oven so that recovery can be the recovered state, and
D2671 − 21
12.1.7 Time and temperature used for shrinkage of the 17.1.1 Procedure A—Bring the mandrel to room tempera-
tubing. ture and thoroughly clean. The means of heat application,
together with the time and method of shrinkage, shall be
13. Precision and Bias
optional as agreed upon between the purchaser and the seller.
17.1.2 Procedure B—Preheatthemandrelforatleast30min
13.1 The overall estimates of the precision within
in an oven at a specified temperature. Place the tubing on the
laboratories, (S ) j, and the precision between laboratories,
r
mandrel; the means of heat application to produce shrinkage
(S )j, are given in Table 1 for four selected materials. These
r
shall be optional as agreed upon between the purchaser and the
estimates are based on a round robin of three specimens, each
seller.
run in six laboratories. No bias statement can be made due to
17.1.3 Procedure C—Bring the mandrel to room
the lack of a standard reference material.
temperature, and position the specimen on the mandrel and
RESTRICTED SHRINKAGE
place it in an oven at a prescribed temperature for a period of
at least 30 min.
14. Significance and Use
NOTE 4—Means of applying heat other than the use of ovens are
14.1 Thistestmethodcoversthedeterminationoftheability
acceptable as agreed upon between the purchaser and the seller.
of heat-shrinkable tubing to be shrunk on a specially designed
17.2 At the end of the specified shrinkage period, remove
mandrel without splitting or cracking. A voltage proof test is
the mandrels and specimens from the heat source, and cool to
used to ascertain splitting or cracking.
room temperature.
15. Apparatus
17.3 Examine the specimens for tightness of fit and for
evidence of cracking or splitting.
15.1 Mandrels—Aseriesofmandrelshavingthedimensions
shown in Fig. 1 and Table 2. Care shall be taken that all sharp
NOTE 5—It is recommended that section B of the mandrel be provided
edges are deburred.
with a longitudinal V-groove to permit easy removal of the shrunk
specimen using a knife or razor blade.
15.2 Oven, forced-convection type, capable of maintaining
temperature to within 65 °C as described in 9.4. 17.4 Wrap a strip of metal foil not more than 0.001 in.
(0.02 mm) thick around the specimen in the area directly over
16. Test Specimens
the disk (A of Fig. 1) so that the foil covers all parts of the disk.
Apply a second layer of foil tightly against the tubing to ensure
16.1 Cut three lengths of tubing, each 6 in. (150 mm) long,
contact, leaving a short length free for an electrical connection.
from the sample of tubing in the expanded state.
Remove a portion of the tubing from one end of the mandrel to
expose a short length for the purpose of making a second
17. Procedure
electrical connection, making sure that sufficient tubing re-
17.1 Heat shrink the specimens on the mandrels shown in
mains between the points of connection and the foil electrode
Fig. 1, using one of the following procedures:
to avoid flashover during the voltage proof test.
17.5 Apply an ac voltage at a rate of 500 V/s to a specified
level of voltage between the electrodes and hold for a period of
1 min.
Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR:D09-1017.
TABLE 1 Estimated Precision of Storage Life Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Expanded inside diameter in. (mm) PTFE 0.11 (2.79) 0.003 (0.076) 0.003 (0.076)
PVC 0.26 (6.60) 0.009 (0.229) 0.010 (0.254)
Polychloroprene 0.95 (24.13) 0.006 (0.152) 0.032 (0.813)
Polyolefin, flexible 2.0 (50.8) 0.020 (0.508) 0.025 (0.635)
Recovered inside diameter in. (mm) PTFE 0.05 (1.27) 0.001 (0.025) 0.002 (0.051)
PVC 0.12 (3.05) 0.001 (0.025) 0.003 (0.076)
Polychloroprene 0.42 (10.67) 0.001 (0.025) 0.005 (0.127)
Polyolefin, flexible 0.96 (24.38) 0.005 (0.127) 0.021 (0.533)
Recovered wall thickness in. (mm) PTFE 0.012 (0.304) 0.0007 (0.0178) 0.0010 (0.0254)
PVC 0.024 (0.609) 0.0007 (0.0178) 0.0011 (0.0594)
Polyolefin, flexible 0.049 (1.245) 0.0009 (0.0229) 0.0015 (0.0381)
Polychloroprene 0.065 (1.651) 0.0007 (0.0178) 0.0031 (0.0787)
Expanded eccentricity % Polychloroprene 12.5 3.0 4.3
Polyolefin, flexible 26 3.1 6.0
Longitudinal change % PVC −18.4 0.6 1.7
Polyolefin, flexible −7.5 1.2 1.7
Polychloroprene −1.9 2.3 2.3
PTFE 30 2.5 3.9
D2671 − 21
where:
A = minimum expanded diameter of tubing as supplied.
B = longer diameter section of the mandrel (Note 5),
D = 75 % of diameter A,
d = 50 % of diameter A,
X = see Table 1,
Y = see Table 1, and
Y = 0.13 mm.
FIG. 1 Mandrel for Restricted Shrinkage Test
TABLE 2 Dimensions for Restricted Shrinkage Test Mandrel
DIELECTRIC BREAKDOWN VOLTAGE AND
Mandrel Section, DIELECTRIC STRENGTH
Maximum Inside Diameter of Tubing
in. (mm)
(Nominal) After Unrestricted
Shrinkage, in. (mm)
XY
20. Significance and Use
A
Less than 0.050 (1.27) 0.5 (13) 0.25 (6.4)
20.1 By the nature of heat-shrinkable tubing, it is possible
0.050 to 0.125 (1.27 to 3.18) 0.5 (13) 0.25 (6.4)
that the wall thickness will vary because of the geometry of the
0.126 to 0.374 (3.20 to 9.50) 1 (25) 0.5 (13)
0.375 to 2.000 (9.52 to 50.80) 2 (51) 2 (51)
object on which it is shrunk. The dielectric breakdown voltage
Greater than 2.000 (50.80) 3 (76) 3 (76)
of a tubing is of importance as a measure of its ability to
A
For tubing sizes less than 0.050 in. (1.27 mm) in inside diameter (after
withstand electrical stress without failure. This value does not
unrestricted shrinkage), use a straight cylindrical mandrel having an outside
correspond to the dielectric breakdown voltage expected in
diameter conforming to dimension D of Fig. 1.
service, but is of potential value in comparing different
materials or different lots, in controlling manufacturing pro-
cesses or, when coupled with experience, for a limited degree
of design work. For a more complete discussion, refer to Test
Method D149.
18. Report
18.1 Report the following information:
21. Apparatus
18.1.1 Identification of the tubing,
21.1 Mandrels—A series of metal mandrels having diam-
18.1.2 Outside dimensions of the mandrel used (A, D, and d eters larger, but not more than 15 % larger, than the nominal
fully recovered diameters of tubing to be tested.
of Fig. 1),
18.1.3 Method of heat shrinking, and the time and tempera-
21.2 Oven, forced-convection type, capable of maintaining
ture of shrinkage, temperature to within 65 °C.
18.1.4 Brief description of the conformability of the speci-
22. Test Specimens
men to the mandrel, together with evidence of cracking or
22.1 Cut five lengths of tubing, each 6 in. (150 mm) long,
splitting,
from the tubing in the expanded state.
18.1.5 Voltage used in the proof test,
18.1.6 Results of the proof voltage test, and
23. Procedure
18.1.7 Location of breakdown, if any.
23.1 (Warning—High Voltage. See 5.1.)
23.2 For tubing having a recovered inside diameter of 1 in.
19. Precision and Bias
(25 mm) or less, choose a mandrel that is slightly larger in
19.1 No statement is made about either the precision or the
diameter than the fully recovered inside diameter of the tubing
bias of this test method for measuring restricted shrinkage
to be tested. Heat shrink the specimen onto the mandrel by
since the result merely states whether there is conformance or
heating it in an oven at the specified time and temperature for
nonconformance to the criteria specified in the procedure. the tubing being tested.
D2671 − 21
23.2.1 Following the heating, remove the mandrel from the HEAT SHOCK
oven and allow it to cool to room temperature. Applya1in.
(25.4 mm) wide metal-foil electrode not more than 0.001 in. 26. Significance and Use
(0.02 mm) thick around the center of the specimen.
26.1 It is not always possible to control precisely the heat
23.3 For tubing having a recovered inside diameter of more source used to effect shrinkage of tubing, and for this reason,
it is possible that the tubing will be exposed to temperatures in
than 1 in. (25.4 mm), heat shrink the specimens in an oven
without a mandrel for the time and temperature specified for excess of those intended for shrinkage.This test method serves
to evaluate the effects on the tubing of short periods of
the tubing being tested. At the end of the heating period,
removethespecimensfromtheoven,cutlengthwise,andwhile exposure to specified temperatures in excess of those normally
recommended for shrinkage. This test is a means of obtaining
still warm, lay out flat to form a sheet. Allow to cool to room
temperature. visual evidence of the effects of elevated temperatures on
heat-shrinkabletubingbyvisualexamination,eitheraloneorin
23.4 Immerse the specimens in oil and determine the
combination with a mandrel wrap procedure following the heat
dielectric breakdown voltage of the shrunk-down specimens
exposure.
using the method described in Test Method D149. For flat test
specimens, use 1-in. (25 mm) electrodes as in Test Method
27. Test Specimens
D149, Table number 1, Electrode Type 2. Make one test on
27.1 Cut three lengths of tubing, each 6 in. (150 mm) long,
each of the five specimens. Use the short-time test at a rate of
rise of 500 V/s. from the sample of tubing in the expanded state. Cut ⁄2-in. (13
mm) wide strips from tubing having an expanded diameter
23.5 For determination of dielectric strength, measure the
greater than 0.5 in. (12.7 mm).
wall thickness immediately adjacent to the point of dielectric
breakdown of each specimen using the method in 11.2.
28. Procedure
23.6 Calculate the dielectric strength by dividing the break-
28.1 Attach a small piece of wire to each specimen so that
down voltage by the wall thickness for each specimen.
the specimen is suspended vertically in the oven during the
test.
24. Report
28.2 Place the specimen in an oven similar to that described
24.1 Report the following information:
in 9.4, maintained at a specified temperature.After a period of
24.1.1 Identification of the tubing,
4 h, remove the specimen and allow it to cool to room
24.1.2 Breakdown voltage in kilovolts for each specimen,
temperature. When required, wrap the specimen 360° around a
24.1.3 Average breakdown voltage for the five specimens,
metal mandrel having a diameter as specified in the tubing
24.1.4 Wall thickness of each specimen in inches or
specification in 2 to 4 s.
millimetres,
24.1.5 Dielectric strength in volts per mil or kilovolts per
28.3 Examine the specimens for evidence of cracking,
millimetre for each specimen, and
flowing, or dripping.
24.1.6 Average dielectric strength for the five specimens.
29. Report
25. Precision and Bias
29.1 Report the following information:
25.1 The overall estimates of the precision within
29.1.1 Identification of the tubing,
laboratories, (S ) j, and the precision between laboratories,
r
29.1.2 Temperature of the test, and
(S )j, are given in Table 3 for four selected materials. These
r
29.1.3 Record of cracking, flow, or dripping.
estimates are based on a round robin of five specimens, each
run in six laboratories. This test method has no bias because
30. Precision and Bias
the results are expressed purely in terms of this test method.
30.1 No statement is made about either the precision or the
bias of this test method for measuring heat shock since the
Supporting data have been filed at ASTM International Headquarters and may
result merely states whether there is conformance or noncon-
beobtainedbyrequestingResearchReportRR:D09-1025.ContactASTMCustomer
Service at [e-mail]. formance to the criteria specified in the procedure.
TABLE 3 Estimated Precision of Tensile Property Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Dielectric breakdown voltage kV PVDF 11.4 1.7 1.8
Polyolefin, semi-rigid 13.3 1.7 2.9
Polyolefin, flexible 19.2 1.6 2.0
Polyolefin, flexible 30 1.9 4.7
Dielectric strength V/mil (kV/mm) Polyolefin, semi-rigid 460 (18.11) 62 (2.44) 110 (4.33)
Polyolefin, flexible 680 (26.77) 39 (1.54) 114 (4.49)
Polyolefin, flexible 850 (33.46) 84 (3.31) 133 (5.24)
PVDF 1100 (43.31) 128 (5.04) 150 (5.90)
D2671 − 21
STORAGE LIFE LOW-TEMPERATURE PROPERTIES
31. Significance and Use 36. Significance and Use
36.1 Flexibility of tubing at low temperatures is an impor-
31.1 In the expanded form, heat-shrinkable tubing is under
stress. Over a period of time there will be a tendency for this tant service property. ProceduresAand C are low-temperature
flexibility tests. Procedure A serves to evaluate tubing by a
stress to relax. Potential effects of this relaxation include the
following: (a) that the tubing no longer meets the minimum- method that simulates actual use in service, but that is
restricted by its physical limitations to tubing having a recov-
expanded dimension, or (b) that it will fail to recover to the
maximum-recovered dimension. This test method provides an ered inside diameter of less than 0.375 in. (9.5 mm). Procedure
C can be used on any size tubing and the test can be performed
accelerated means of evaluating the utility of heat-shrinkable
tubingafteraperiodofstorageunderprescribedconditionsand on tubing in either the expanded or fully recovered condition.
Alternatively, a brittleness temperature test (Procedure B)
assists in determining the need for special storage and handling
requirements. serves to evaluate low-temperature impact resistance of speci-
mens of prescribed form and is not restricted to certain sizes.
32. Test Specimens
37. Apparatus
32.1 Cut three lengths of tubing, each 6 in. (150 mm) long,
37.1 Cold Chamber—A thermally insulated enclosure
from the sample of tubing in the expanded state.
equipped to maintain an atmosphere at a specified low tem-
33. Procedure
perature to within 62 °C, and of such size as to permit
convenient bending of specimens around mandrels without
33.1 Measure the inside diameter of the specimens in
removal from the chamber.
accordance with 11.1.
37.2 Stranded Wire, sizes AWG 0 to 30 (9.5 to 0.25 mm).
33.2 Place the specimens in an oven of the forced-
convection type and capable of maintaining a temperature of
37.3 Mandrels, stainless steel. Sizes are to be specified in
40 6 2 °C (104 6 4 °F) (or other specified temperature) for a
tubing specification.
period of two weeks.
38. Test Specimens
33.3 Remove the specimens and allow them to cool to room
38.1 Procedure A—Cut three lengths of tubing, each 18 in.
temperature. Measure the inside diameter of each specimen in
(460 mm) long, from the sample of tubing in the expanded
accordance with 11.1.
state.
33.4 Shrink the specimens and measure the inside diameter
38.2 Procedure B—Cut ten 1.5-in. (38 mm) lengths of
and wall thickness in accordance with 11.1 and 11.2.
tubing from the sample of tubing in the recovered (shrunk)
34. Report
state. For tubing of inside diameter 0.148 in. (3.76 mm) or less,
specimens are to be in full-section form; for tubing of inside
34.1 Report the following information:
diameter greater than 0.148 in., specimens are to be in the form
34.1.1 Identification of the tubing,
of strips 0.25 in. (6.4 mm) wide by 1.5 in. long.
34.1.2 Inside diameter of the tubing before conditioning,
after two weeks of conditioning, and after heat shrinking,
38.3 Procedure C—Cut three specimens each 12 in.
34.1.3 Wall thickness after heat-shrinking, and
(300 mm) long from the sample. For tubing having a recovered
34.1.4 Temperature of the storage-life test, if other than
diameter greater than 0.4 in. (10 mm) the specimens shall be
40 °C. 1
⁄4-in.(6.4mm)widestripscutfromthe12-in.lengthoftubing.
NOTE 6—Because no flexible mandrel is readily available that can be
35. Precision and Bias
conveniently used to test tubing of inside diameter greater than AWG 0
35.1 The overall estimates of the precision within
(10 mm), Procedure A is restricted to tubing of inside diameter in the
laboratories, (S ) j, and the precision between laboratories, recovered state of less than 0.40 in. (10 mm).
r
(S )j, are given in Table 4 for two selected materials. These
r
39. Procedure A—Low-temperature Flexibility
estimates are based on a round robin of three specimens, each
run in six laboratories. This test method has no bias because 39.1 Select a stranded wire that is the nearest AWG size
the results are expressed purely in terms of this test method. which is larger than the specified fully recovered diameter of
TABLE 4 Estimated Precision of Storage Life Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Expanded inside diameter in. (mm) PVC 0.26 (6.60) 0.005 (0.127) 0.011 (0.279)
Polychloroprene 0.95 (24.13) 0.002 (0.051) 0.012 (0.305)
Recovered inside diameter in. (mm) PVC 0.12 (3.05) 0.002 (0.051) 0.004 (0.102)
Polychloroprene 0.43 (10.92) 0.002 (0.051) 0.008 (0.203)
Recovered wall in. (mm) PVC 0.023 (0.584) 0.0011 (0.028) 0.0019 (0.048)
Polychloroprene 0.064 (1.626) 0.0011 (0.028) 0.0031 (0.079)
D2671 − 21
the specimen being tested. See Table 5 for stranded wire sizes 42.2.3 Temperature of the cold chamber, and
suitable for use with common fractional inch tubing sizes. 42.2.4 Number of specimens failed.
39.2 Locate the specimen centrally on a 24-in. (610 mm) 42.3 Report the following information on low-temperature
length of stranded wire and heat shrink the tubing in accor- flexibility (Procedure C):
dance with 11.1.3. 42.3.1 Identification of the tubing,
42.3.2 Nominal size of the tubing,
39.3 Condition the specimens in the cold chamber for a
42.3.3 Size of the mandrel used,
period of1hatthe specified temperature along with mandrels
42.3.4 Temperature of the cold chamber, and
of the specified diameter.
42.3.5 Record of cracking of the tubing after wrapping.
39.4 After the conditioning period, and while at the speci-
43. Precision and Bias
fied low temperature, and without removing the specimens
from the chamber, bend the tubing around the mandrel for not
43.1 No statement is made about either the precision or the
less than one complete wrap (360°) at a uniform speed of 10 6
bias of this test method for measuring low-temperature prop-
2 s per wrap.
erties since the result merely states whether there is confor-
39.5 Remove the specimens and the mandrels from the cold mance or nonconformance to the criteria specified in the
chamber and immediately examine them for evidences of procedure.
cracking of the tubing.
TENSILE STRENGTH AND ULTIMATE
40. Procedure B—Brittleness Temperature ELONGATION
40.1 Using Procedure A of Test Method D746, conduct
44. Test Specimens
brittleness temperature tests at a specified low temperature.
44.1 For tubing of recovered inside diameter not greater
than 0.33 in. (8.4 mm), cut five lengths, each 4 in. (100 mm)
41. Procedure C—Low-temperature Flexibility
long, from the tubing in the recovered state.
41.1 Condition the specimens in the cold chamber for4hat
44.2 For tubing of recovered inside diameter greater than
the specified temperature along with mandrels of the specified
0.33 in. (8.4 mm), prepare five specimens from tubing in the
diameter.
recovered state by die cutting in accordance withTest Methods
41.2 Upon completion of this conditioning and at this same
D412, with the long dimension of the die parallel to the
temperature, wrap the specimens not less than 360° about the
longitudinal axis of the tubing.
mandrel in approximately 10 6 2 s. Visually examine the
44.2.1 Prepare elastomeric and flexible plastic tubing with a
specimens for cracks after removal from the cold chamber.
secant modulus of up to 25 000 psi in the form of Die C ofTest
Methods D412.
42. Report
44.2.2 Prepare all other plastic tubing in the form of Die D
42.1 Report the following information on low-temperature
of Test Methods D412.
flexibility (Procedure A):
42.1.1 Identification of the tubing,
45. Procedure
42.1.2 Specified inside diameter of the tubing specimens,
45.1 For use in determining elongation, mark two parallel
42.1.3 Size of the wire used,
gage lines on the tubing or die specimens, 1 in. (25 mm) apart
42.1.4 Size of the mandrel used,
and centrally located on the specimen.Alternatively, make this
42.1.5 Temperature of the cold chamber, and
measurement with an extensiometer apparatus.
42.1.6 Record of cracking of the tubing after flexing.
45.2 For purposes of calculating tensile strength, measure
42.2 Report the following information on brittleness tem-
the inside diameter and wall thickness of the specimens in
perature (Procedure B):
accordance with the methods in 11.1 and 11.2, selecting those
42.2.1 Identification of the tubing,
measurementswhichwillprovidetheminimumcross-sectional
42.2.2 Form of the specimens tested,
area for each specimen.
45.3 For elastomeric and flexible tubing (44.2.1), set the
TABLE 5 Stranded Wire Flexible Mandrel Sizes for Procedure A
grips of the testing machine 2 in. (50 mm) apart for tubing
Low-temperature Flexibility
specimens and 2.5 in. (65 mm) for die cut specimens, and
Specified Diameter of Recovered Tubing,
AWG Wire Size
locate the specimens so that the bench marks are centrally
in. (mm)
spaced between the grips.
0.023 (0.59) 24
0.031 (0.76) 22
45.4 For all other tubing (44.2.2), perform the test as in
0.047 (1.16) 18
Section 45 using grips spaced 1 in. (25 mm) apart.
0.062 (1.60) 14
0.093 (2.34) 10
45.5 Determine the breaking force and ultimate elongation
0.125 (3.18) 8
0.187 (4.75) 6 in accordance with Test Methods D412, except use a rate of
0.250 (6.35) 4
jaw separation as specified in the tubing specification for the
0.312 (7.92) 2
material being tested. Retest any specimen that breaks outside
0.375 (9.53) 0
the bench marks.
D2671 − 21
45.6 A retest is not required for specimens that break 51. Test Specimens
outside the benchmark when (1) the actual value of elongation
51.1 Prepare five specimens in accordance with Section 44.
is not required (for example, in a pass-fail quality control
application) and (2) the minimum specified value is achieved
52. Procedure
prior to break.
52.1 Suspend the specimens in the oven for a specified
period of time and at the selected temperature.
46. Calculation
52.2 Remove the specimens, allow them to cool to room
46.1 Calculate the tensile strength and ultimate elongation
temperature, and determine the tensile strength and ultimate
in accordance with Test Methods D412.
elongation as required in accordance with Sections 44 to 47,
disregarding any change in color of the specimens after heat
47. Report
aging.
47.1 Report the following information:
47.1.1 Identification of tubing, 53. Report
47.1.2 Rate of jaw separation used,
53.1 Report the following information:
47.1.3 Individual and averaged values for tensile strength in
53.1.1 Identification of the tubing,
pounds-force per square inch (megapascals), and
53.1.2 Oven temperature,
47.1.4 Individual and averaged values for ultimate elonga-
53.1.3 Period of exposure to heat,
tion in percent.
53.1.4 Tensile strength in pounds-force per square inch
(megapascals) for the aged specimens when required together
48. Precision and Bias
with the value reported in 47.1.3, and
48.1 The overall estimates of the precision within
53.1.5 Ultimate elongation, in percent, for the aged
laboratories, (S ) j, and the precision between laboratories,
specimens, together with the value reported in 47.1.4.
r
(S )j, are given in Table 6for four selected materials. These
r
54. Precision and Bias
estimates are based on a round robin of five specimens, each
run in six laboratories. No bias statement can be made due to
54.1 The overall estimates of the precision within
the lack of a standard reference material.
laboratories, (S )j, and the precision between laboratories,
r
(S )j, are given in Table 7 for four materials. These estimates
R
HEAT RESISTANCE
are based on a round robin of five specimens, each run in five
laboratories. This test method has no bias because the results
49. Significance and Use
are expressed purely in terms of this test method.
49.1 The reduction of tensile strength or ultimate elongation
COLOR
duetoexposuretoelevatedtemperaturesisindicativeoflossof
volatile constituents or of chemical changes in the tubing. The
55. Color
specified temperature is sufficiently high to permit the use of a
relatively short exposure period so that the test is suitable as an 55.1 Determine the color of the tubing in the expanded
acceptance test for process control. Longer exposure times at
condition in accordance with Test Method D1535.As an
other temperatures are potentially desirable for research pur- alternative method when permitted, use the procedure de-
poses.
scribedunderMilitarySpecificationMIL-STD-104,employing
color chips.
50. Apparatus
50.1 Oven, forced-convection type with an air velocity of
Supporting data have been filed at ASTM International Headquarters and may
between 100 and 200 ft/min (0.5 and 1 m/s), capable of
beobtainedbyrequestingResearchReportRR:D09-1028.ContactASTMCustomer
maintaining temperature within 62.5 °C. Service at [e-mail].
TABLE 6 Estimated Precision of Dielectric Property Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Tensile strength psi (MPa) Polyolefin, flexible 1600 (11.0) 70 (0.48) 100 (0.69)
Polychloroprene 1700 (11.7) 60 (0.41) 150 (1.03)
Polyolefin, semi-rigid 2300 (15.9) 110 (0.76) 260 (1.79)
PVC 3100 (21.4) 130 (0.90) 260 (1.79)
Ultimate elongation % PVC 270 30 30
Polyolefin, flexible 370 20 20
Polyolefin, semi-rigid 410 30 40
Polychloroprene 430 20 50
Stress modulus (tensile stress) at 200 % psi (MPa) Polychloroprene 870 (6.0) 40 (0.28) 110 (0.76)
PTFE 5500 (37.9) 600 (4.14) 670 (4.62)
D2671 − 21
TABLE 7 Estimated Precision for Heat Resistance Property Measurements for Four Tubings
Property Units Tubing Type Nominal Value (S ) (S )
r j R j
Tensile strength psi (MPa) Polyolefin, flexible whole tube specimen 2260 (15.6) 117 (0.81) 156 (1.08)
Polyolefin, flexible die cut specimen 2220 (15.3) 84 (0.58) 183 (1.26)
PVC 3130 (21.6) 68 (0.47) 155 (1.07)
Polychloroprene 1610 (11.1) 53 (0.37) 70 (0.48)
Ultimate elongation % Polyolefin, flexible whole tube specimen 320 19 25
Polyolefin, flexible die cut specimen 380 16 32
PVC 220 18 35
Polychloroprene 340 19 26
56. Precision and Bias FLUID RESISTANCE
56.1 No statement is made about either the precision or the
63. Significance and Use
bias of this test method for measuring color since the result
63.1 Resistance of tubing to attack by fluid is dependent on
merelystateswhetherthereisconformanceornonconformance
the nature of the compound and the processing conditions used
to the criteria specified in the procedure.
in the manufacture of the tubing, the composition of the fluid,
COLOR STABILITY
and the time and temperature of exposure. This test serves to
evaluate the effects of fluid immersion on tubing by means of
57. Significance and Use determining changes, if any, in tensile strength, ultimate
elongation, breakdown voltage or dielectric strength, of treated
57.1 For purposes of coding, it is important that the color of
specimens.
tubing shall be sufficiently stable during service life so that one
color cannot be mistaken for another. By means of an accel-
64. Test Specimens
erated aging test at an elevated temperature in the absence of
64.1 For each fluid evaluated, cut ten lengths, each 6 in.
light, this test method indicates the extent of the change, if any,
(150 mm) long, from the sample of tubing.
in the color of tubing by reference to standard color notations
64.1.1 Prepare five of these specimens for the tensile
or to standard colors.
strength test in accordance with Section 44. If weight change is
to be determined, weigh each of the fully prepared tensile
58. Apparatus
specimens using an analytical balance capable of reading
58.1 Oven, forced-convection type, capable of maintaining
0.0001g.
temperature to within 62.5 °C (64.5 °F).
64.1.2 Prepare the other five specimens for the dielectric
breakdown or dielectric strength test, in accordance with
59. Test Specimens
Section 22. Recover specimens which have a recovered diam-
59.1 Cut three lengths of tubing, each 4 in. (100 mm) long, eter of 1 in. (25.4 mm) or less without mandrels using the
from the sample of tubing in the expanded state.
procedure of 11.1.3. Recover larger size specimens using the
procedure of 23.3.
60. Procedure
65. Procedure
60.1 Place the specimens in an oven for the time and
65.1 Immerse ten specimens in each fluid for a period of 24
temperature specified. If the time is not specified, it shall be for
6 2 h at a specified temperature, using a volume of fluid not
a period of 24 h.
less than 20 times that of the specimens, and making sure that
60.2 Remove the specimens, allow them to cool to room
the container is not affected by the fluid under the conditions of
temperature, and determine the color in accordance with 55.1.
the test.
65.2 Remove the specimens from the fluid, lightly wipe dry,
61. Report
andallowthemtoairdryfor45 615minatroomtemperature.
61.1 Report the following information:
65.3 When weight change is being determi
...

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: D2671 − 13 D2671 − 21
Standard Test Methods for
Heat-Shrinkable Tubing for Electrical Use
This standard is issued under the fixed designation D2671; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 These test methods cover the testing of heat-shrinkable tubing used for electrical insulation. Materials used include poly(vinyl
chloride), polyolefins, fluorocarbon polymers, silicone rubber, and other plastic or elastomeric compounds.
1.2 The procedures These test methods appear in the following sections:
Test
Procedure Section(s)
Method(s)
Adhesive Peel Strength 94 – 100
Brittleness Temperature 40 D746
Color 55 and 56 D1535
Color Stability 57 – 62 D1535
Conditioning 7 D618
Copper Stability 89
Corrosion Testing 85 – 91
Dielectric Breakdown 20 – 25 D149
Dimensions 8 – 13 D876
Flammability 68 D8355
(Methods A, C, or D)
Fluid Resistance 63 – 67
Fungus Resistance 100 – 104
Heat Resistance 49 – 54
Heat Shock 26 – 30
Low-temperature Properties 36 – 43
Restricted Shrinkage 14 – 19
Selection of Test Specimens 6
Secant Modulus 77 – 80 D882
Storage Life 31 – 35
Specific Gravity 69 and 70 D792
Stress Modulus 81 – 84 D412
Tensile Strength and Ultimate Elongation 44 – 48 D412
Thermal Endurance 92 and 93
Volume Resistivity 71 – 74 D257
Water Absorption 75 and 76 D570
Melting Point 100 – 104 D3418
ASTM Method
Procedure Sections Reference
Adhesive Peel Strength 98 – 104
Brittleness Temperature 40 D746
Color 55 and 56 D1535
Color Stability 57 – 62 D1535
These test methods are under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and are the direct responsibility of Subcommittee
D09.07 on Electrical Insulating Materials.
Current edition approved Nov. 1, 2013Jan. 1, 2021. Published December 2013February 2021. Originally approved in 1967. Last previous edition approved in 20092013
as D2671 – 09.D2671 – 13. DOI: 10.1520/D2671-13.10.1520/D2671-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2671 − 21
Conditioning 7 D618
Copper Stability 93
Corrosion Testing 89 – 95
Dielectric Breakdown 20 – 25 D149
Dimensions 8 – 13 D876
Flammability 68 – 72 D876
Fluid Resistance 63 – 67
Fungus Resistance 104 – 108
Heat Resistance 49 – 54
Heat Shock 26 – 30
Low-Temperature Properties 36 – 43
Restricted Shrinkage 14 – 19
Selection of Test Specimens 6
Secant Modulus 81 – 84 D882
Storage Life 31 – 35
Specific Gravity 73 and 74 D792
Stress Modulus 85 – 88 D412
Tensile Strength and Ultimate Elongation 44 – 48 D412
Thermal Endurance 96 and 97
Volume Resistivity 75 – 78 D257
Water Absorption 79 and 80 D570
Melting Point 104 – 108 D3418
1.3 This is a fire-test-response standard.
1.3 The values stated in inch-pound units are to be regarded as standard, except for temperature, which shall be expressed in
degrees Celsius. The values given in parentheses are mathematical conversions to SI units that are provided for information only
and are not considered standard.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific hazard statements, see SectionsSection 5 and 68.2for fire test safety
caveats see Test Methods D8355.
NOTE 1—These test methods are similar, but not identical to, those in IEC 60684–260684-2 (see also Note 9).
1.5 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:
D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at
Commercial Power Frequencies
D257 Test Methods for DC Resistance or Conductance of Insulating Materials
D412 Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension
D570 Test Method for Water Absorption of Plastics
D618 Practice for Conditioning Plastics for Testing
D746 Test Method for Brittleness Temperature of Plastics and Elastomers by Impact
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D876 Test Methods for Nonrigid Vinyl Chloride Polymer Tubing Used for Electrical Insulation
D882 Test Method for Tensile Properties of Thin Plastic Sheeting
D1535 Practice for Specifying Color by the Munsell System
D1711 Terminology Relating to Electrical Insulation
D3418 Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential
Scanning Calorimetry
E176 Terminology of Fire Standards
D8355 Test Methods for Flammability of Electrical Insulating Materials Used for Sleeving or Tubing
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.
D2671 − 21
2.2 Other Documents:IEC Standards:
MIL-STD 104 Limits for Electrical Insulation Color
IEC Publication 216 Guide for the Determination of Thermal Endurance Properties of Electrical Insulating Materials
IEC Publication 60684 Specification for Flexible Insulating Sleeving
ISO 846 Plastics—Evaluation of the Action of Microorganisms
2.3 Military Standard:
MIL-STD-104 Limits for Electrical Insulation Color
2.4 ISO Standard:
ISO 846 Plastics—Evaluation of the Action of Microorganisms
3. Terminology
3.1 Definitions:
3.1.1 For definitions pertaining to electrical insulation, refer to Terminology D1711.
3.1.2 For definitions pertaining to fire standards, refer to Terminology E176.
3.1.3 heat-shrinkable tubing, n—tubing that will reduce in diameter from an expanded size to a predetermined size by the
application of heat.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 brittleness temperature, n—the temperature at which 50 % of the specimens fail when the specified number are tested using
the apparatus and conditions specified.
3.2.2 concentricity, n—the ratio expressed in percent of the minimum wall thickness to the maximum wall thickness.
3.2.3 longitudinal change, n—the change in length, either positive or negative, that occurs when the tubing is allowed to freely
recover at the recommended recovery temperature, expressed as a percentage of the as supplied or expanded length.
3.2.4 low-temperature flexibility, n—the resistance to cracking of tubing when wrapped around prescribed mandrels at specified
temperatures.
3.2.5 restricted shrinkage, n—shrinkage of the tubing at a prescribed temperature over a specially designed mandrel whose
smallest diameter is greater than the fully shrunk size and whose largest diameter is less than the expanded size of the tubing.
3.2.6 storage-life, heat-shrinkable tubing, n—the length of time that the tubing will retain its specified expanded and recovered
dimensions under storage at a specified temperature.
4. Significance and Use
4.1 These test methods include most of the important tests used to characterize heat-shrinkable tubing. They are intended primarily
for, but not limited to, extruded heat-shrinkable tubing.
4.2 It is acceptable to use variations in these test methods or alternate contemporary methods of measurement to determine the
values for the properties in this standard provided such methods ensure quality levels and measurement accuracy equal to or better
than those prescribed herein. It is the responsibility of the organizations using alternate test methods to be able to demonstrate this
condition. In cases of dispute, the methods specified herein shall be used.
NOTE 2—Provision for alternate methods is necessary because of (1) the desire to simplify procedures for specific applications without altering the result,
and (2) the desire to eliminate redundant testing and use data generated during manufacturing process control, including that generated under Statistical
Available from Standardization Documents Order Desk, Bldg. 4 Section D, DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA 19111-5094,
Attn: NPODS.http://quicksearch.dla.mil.
Available from International Electrotechnical Commission (IEC), 3, rue de Varembé, 1st floor, P.O. Box 131, CH-1211, Geneva 20, Switzerland, https://www.iec.ch.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.International Organization for
Standardization (ISO), ISO Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland, https://www.iso.org.
D2671 − 21
Process Control (SPC) conditions, using equipment and methods other than those specified herein. An example would be the use of laser micrometers
or optical comparators to measure dimensions.
5. Hazards
5.1 Warning(Warning—Lethal voltages are potentially present during this test. It is essential that the test apparatus, and all
associated equipment that is potentially electrically connected to it, be properly designed and installed for safe operation. Solidly
ground all electrically conductive parts that any person might come in contact with during the test. Provide means for use at the
completion of any test to ground any parts which: (a) were at high voltage during the test, (b) have potentially acquired an induced
charge during the test, or (c) could have retained a charge even after disconnection of the voltage source. Thoroughly instruct all
operators in the proper way to conduct tests safely. When making high voltage tests, particularly in compressed gas or in oil, it
is possible that the energy released at breakdown would be sufficient to result in fire, explosion, or rupture of the test chamber.
Design test equipment, test chambers, and test specimens so as to minimize the possibility of such occurrences and to eliminate
the possibility of personal injury. See Section 23.—)Lethal voltages are potentially present during this test. It is essential that the
test apparatus, and all associated equipment that is potentially electrically connected to it, be properly designed and installed for
safe operation. Solidly ground all electrically conductive parts that any person might come in contact with during the test. Provide
means for use at the completion of any test to ground any parts which: (a) were at high voltage during the test; (b) have potentially
acquired an induced charge during the test; or (c) could have retained a charge even after disconnection of the voltage source.
Thoroughly instruct all operators in the proper way to conduct tests safely. When making high voltage tests, particularly in
compressed gas or in oil, it is possible that the energy released at breakdown would be sufficient to result in fire, explosion, or
rupture of the test chamber. Design test equipment, test chambers, and test specimens so as to minimize the possibility of such
occurrences and to eliminate the possibility of personal injury. (See Section 23.)
5.2 Flammable Solvents:
5.2.1 Methyl ethyl ketone is a volatile, flammable solvent. It shall be handled in an area having good ventilation, such as a
laboratory hood and away from sources of ignition. See Section 10096.
6. Selection of Test Specimens
6.1 Select a sufficient number of pieces of tubing in such manner as to be representative of the shipment.
6.2 Cut specimens, free of kinks, from the sample selected under 6.1. Cut perpendicular to the longitudinal axis of the tubing and
in such manner that the specimen has cleanly cut square edges.
6.3 Unless otherwise stated, conduct tests on specimens in the completely shrunk condition.
7. Conditioning
7.1 When specified, condition tubing in accordance with Practice D618 using Procedure A, except that a conditioning time of 4
h shall be used. In cases where tests are performed on specimens in the shrunk state, condition the test specimens prior to testing,
but after heat shrinking.
DIMENSIONS
8. Significance and Use
8.1 Inside Diameter—The inside diameter of tubing before and after heat-shrinking is an important factor in selecting tubing of
the proper size to slip easily over an object and to conform tightly after shrinkage.
8.2 Wall Thickness—Wall thickness measurements are useful in providing design data and in calculating certain physical and
electrical properties of the tubing.
8.3 Concentricity—In some cases, a thin wall area, due to variation in processing, will lead to equipment failure. It is important,
therefore, both in extrusion of the tubing, and its expansion prior to shrinkage in end-use, that concentricity be held above a
specified limit to ensure proper performance of the tubing.
D2671 − 21
8.4 Length—The length, both before and after heat-shrinking, is important in the determination of proper fit of the tubing in
end-use.
9. Apparatus
9.1 Mandrels—Use a series of steel rods suitable for insertion into the tubing including the tapered gages described under Test
Methods D876.
9.2 Micrometers, mandrel anvil and indicator set accurate to at least 0.001 in. or 0.02 mm.
9.3 Steel Scale, graduated in ⁄64-in. or 0.5-mm 0.5 mm divisions.
9.4 Oven, forced-convection type, capable of maintaining temperature to within 65°C.65 °C.
10. Test Specimens
10.1 Cut three straight lengths of expanded tubing, each 6 in. (150 mm) long, from the sample as directed in 6.2 for each test
performed.
11. Procedure
11.1 Measuring Inside Diameter:
11.1.1 Select a mandrel that will just fit into the specimen and insert the mandrel into the expanded tubing for a distance of 1 in.
(25 mm).
NOTE 3—If the tubing specimens have a tendency to adhere to the mandrels during measurement of diameter, it is recommended that the mandrels be
coated with water or talc as a lubricant. However, caution must be exercised not to force the tubing on the mandrel, thereby stretching the specimens.
11.1.2 Using a machinist’s micrometer, measure the outside diameter of the mandrel to the nearest 0.001 in. (0.02 mm). Record
this as the expanded inside diameter.
11.1.3 Place the specimen in an oven at the temperature specified as suitable for complete shrinkage for a period of time
recommended for shrinkage. Make provision for positioning the specimen horizontally in the oven so that recovery can be effected
without restriction. If the tubing tends to become sticky at the shrinkage temperature, specimens can be laid in trays that have been
powdered slightly with talc.
11.1.4 At the end of the specified shrinkage time, remove the specimens from the oven and allow to cool to room temperature.
Measure the inside diameter as described in 11.1.111.1.1 and 11.1.2 and 11.1.2, recording this as the recovered inside diameter.
11.2 Measuring Wall Thickness:
11.2.1 Measure the wall thickness of the expanded (as supplied) tubing using a micrometer. By means of a sufficient number of
tests, locate the points on the wall corresponding to the minimum and the maximum wall thickness, and record these measurements
to the nearest 0.001 in. (0.02 mm).
11.2.2 Allow the specimens to recover under heat as described in 11.1.311.1.3 and 11.1.4 and 11.1.4. Measure the wall thickness
as described in 11.2.1 recording these as the recovered thicknesses.
11.3 Calculating Concentricity—From measurements of minimum and maximum wall thickness made in accordance with
11.2.111.2.1 and 11.2.2 and 11.2.2, calculate the concentricity (C) of the expanded and recovered tubing respectively, using the
following equation:
C 5 100 M"/M' (1)
~ !
D2671 − 21
where:
M' = maximum thickness, in. (mm), and
M = minimum thickness, in. (mm).
"
M" = minimum thickness, in. (mm).
11.4 Measuring Length:
11.4.1 Using the steel scale, measure the length to the nearest ⁄32 in. or 1 mm.
11.4.2 Allow the specimens to recover under heat as described in 11.1.311.1.3 and 11.1.4 and 11.1.4. Measure the length after
recovery. Record the length in the expanded and recovered state.
11.5 Calculating Longitudinal Change—From the measurements of expanded and recovered length made in accordance with
11.4.111.4.1 and 11.4.2 and 11.4.2, calculate the percent longitudinal change using the following equation:
Percent longitudinal change 5 100 L'2L" /L" (2)
~ !
percent longitudinal change 5 100 ~L'2L"!/L" (2)
where:
L' = recovered length, in. (mm), and
L" = expanded length, in. (mm).
12. Report
12.1 Report the following information:
12.1.1 Identification of the tubing,
12.1.2 Inside diameter of the tubing in the expanded and in the recovered state,
12.1.3 Maximum and minimum wall thickness for each specimen in the expanded and in the recovered state,
12.1.4 Length of each specimen in the expanded and recovered state,
12.1.5 Percentage longitudinal change of each specimen (after recovery) based on the expanded state length,
12.1.6 Concentricity of each specimen in the expanded and the recovered state, and
12.1.7 Time and temperature used for shrinkage of the tubing.
13. Precision and Bias
13.1 The overall estimates of the precision within laboratories, (S ) j, and the precision between laboratories, (S )j, are given in
r r
Table 1 for four selected materials. These estimates are based on a round robin of three specimens, each run in six laboratories.
No bias statement can be made due to the lack of a standard reference material.
RESTRICTED SHRINKAGE
14. Significance and Use
14.1 This test method covers the determination of the ability of heat-shrinkable tubing to be shrunk on a specially designed
mandrel without splitting or cracking. A voltage proof test is used to ascertain splitting or cracking.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D09-1017.
D2671 − 21
TABLE 1 Estimated Precision of Storage Life Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Expanded inside diameter in. (mm) PTFE 0.11 (2.79) 0.003 (0.076) 0.003 (0.076)
PVC 0.26 (6.60) 0.009 (0.229) 0.010 (0.254)
Polychloroprene 0.95 (24.13) 0.006 (0.152) 0.032 (0.813)
Polyolefin, flexible 2.0 (50.8) 0.020 (0.508) 0.025 (0.635)
Polyolefin, flexible 2.0 (50.8) 0.020 (0.508) 0.025 (0.635)
Recovered inside diameter in. (mm) PTFE 0.05 (1.27) 0.001 (0.025) 0.002 (0.051)
PVC 0.12 (3.05) 0.001 (0.025) 0.003 (0.076)
Polychloroprene 0.42 (10.67) 0.001 (0.025) 0.005 (0.127)
Polyolefin, flexible 0.96 (24.38) 0.005 (0.127) 0.021 (0.533)
Recovered wall thickness in. (mm) PTFE 0.012 (0.304) 0.0007 (0.0178) 0.0010 (0.0254)
PVC 0.024 (0.609) 0.0007 (0.0178) 0.0011 (0.0594)
Polyolefin, flexible 0.049 (1.245) 0.0009 (0.0229) 0.0015 (0.0381)
Polychloroprene 0.065 (1.651) 0.0007 (0.0178) 0.0031 (0.0787)
Expanded eccentricity % Polychloroprene 12.5 3.0 4.3
Polyolefin, flexible 26 3.1 6.0
Longitudinal change % PVC −18.4 0.6 1.7
Polyolefin, flexible −7.5 1.2 1.7
Polychloroprene −1.9 2.3 2.3
PTFE 30 2.5 3.9
15. Apparatus
15.1 Mandrels—A series of mandrels having the dimensions shown in Fig. 1 and Table 2. Care shall be taken that all sharp edges
are deburred.
15.2 Oven, forced-convection type, capable of maintaining temperature to within 65°C 65 °C as described in 9.4.
16. Test Specimens
16.1 Cut three lengths of tubing, each 6 in. (150 mm) long, from the sample of tubing in the expanded state.
17. Procedure
17.1 Heat shrink the specimens on the mandrels shown in Fig. 1, using one of the following procedures:
17.1.1 Procedure A—Bring the mandrel to room temperature and thoroughly clean. The means of heat application, together with
the time and method of shrinkage, shall be optional as agreed upon between the purchaser and the seller.
17.1.2 Procedure B—Preheat the mandrel for at least 30 min in an oven at a specified temperature. Place the tubing on the mandrel;
the means of heat application to produce shrinkage shall be optional as agreed upon between the purchaser and the seller.
17.1.3 Procedure C—Bring the mandrel to room temperature, and position the specimen on the mandrel and place it in an oven
at a prescribed temperature for a period of at least 30 min.
NOTE 4—Means of applying heat other than the use of ovens are acceptable as agreed upon between the purchaser and the seller.
17.2 At the end of the specified shrinkage period, remove the mandrels and specimens from the heat source, and cool to room
temperature.
17.3 Examine the specimens for tightness of fit and for evidence of cracking or splitting.
NOTE 5—It is recommended that section B of the mandrel be provided with a longitudinal V-groove to permit easy removal of the shrunk specimen using
a knife or razor blade.
17.4 Wrap a strip of metal foil not more than 0.001 in. (0.02 mm) (0.02 mm) thick around the specimen in the area directly over
the disk (A of Fig. 1) so that the foil covers all parts of the disk. Apply a second layer of foil tightly against the tubing to ensure
D2671 − 21
A = minimum expanded diameter of tubing as supplied.
B = longer diameter section of the mandrel (Note 5).
D = 75 % of diameter A.
d = 50 % of diameter A.
X = See Table 1.
Y = See Table 1.
⁄8 in. = 0.13 mm.
where:
A = minimum expanded diameter of tubing as supplied.
B = longer diameter section of the mandrel (Note 5),
D = 75 % of diameter A,
d = 50 % of diameter A,
X = see Table 1,
Y = see Table 1, and
Y = 0.13 mm.
FIG. 1 Mandrel for Restricted Shrinkage Test
TABLE 2 Dimensions for Restricted Shrinkage Test Mandrel
Mandrel Section,
Maximum Inside Diameter of Tubing
in. (mm)
(Nominal) After Unrestricted
Shrinkage, in. (mm)
X Y
A
Less than 0.050 (1.27) 0.5 (13) 0.25 (6.4)
0.050 to 0.125 (1.27 to 3.18) 0.5 (13) 0.25 (6.4)
0.126 to 0.374 (3.20 to 9.50) 1 (25) 0.5 (13)
0.375 to 2.000 (9.52 to 50.80) 2 (51) 2 (51)
Greater than 2.000 (50.80) 3 (76) 3 (76)
A
For tubing sizes less than 0.050 in. (1.27 mm) in inside diameter (after
unrestricted shrinkage), use a straight cylindrical mandrel having an outside
diameter conforming to dimension D of Fig. 1.
contact, leaving a short length free for an electrical connection. Remove a portion of the tubing from one end of the mandrel to
expose a short length for the purpose of making a second electrical connection, making sure that sufficient tubing remains between
the points of connection and the foil electrode to avoid flashover during the voltage proof test.
D2671 − 21
17.5 Apply an ac voltage at a rate of 500 V/s to a specified level of voltage between the electrodes and hold for a period of 1 min.
18. Report
18.1 Report the following information:
18.1.1 Identification of the tubing,
18.1.2 Outside dimensions of the mandrel used (A, D, and d of Fig. 1),
18.1.3 Method of heat shrinking, and the time and temperature of shrinkage,
18.1.4 Brief description of the conformability of the specimen to the mandrel, together with evidence of cracking or splitting,
18.1.5 Voltage used in the proof test,
18.1.6 Results of the proof voltage test, and
18.1.7 Location of breakdown, if any.
19. Precision and Bias
19.1 No statement is made about either the precision or the bias of this test method for measuring restricted shrinkage since the
result merely states whether there is conformance or nonconformance to the criteria specified in the procedure.
DIELECTRIC BREAKDOWN VOLTAGE AND DIELECTRIC STRENGTH
20. Significance and Use
20.1 By the nature of heat-shrinkable tubing, it is possible that the wall thickness will vary because of the geometry of the object
on which it is shrunk. The dielectric breakdown voltage of a tubing is of importance as a measure of its ability to withstand
electrical stress without failure. This value does not correspond to the dielectric breakdown voltage expected in service, but is of
potential value in comparing different materials or different lots, in controlling manufacturing processes or, when coupled with
experience, for a limited degree of design work. For a more complete discussion, refer to Test Method D149.
21. Apparatus
21.1 Mandrels—A series of metal mandrels having diameters larger, but not more than 15 % larger, than the nominal fully
recovered diameters of tubing to be tested.
21.2 Oven, forced-convection type, capable of maintaining temperature to within 65°C.65 °C.
22. Test Specimens
22.1 Cut five lengths of tubing, each 6 in. (150 mm) long, from the tubing in the expanded state.
23. Procedure
Warning—High Voltage (see 5.1).
23.1 (Warning—High Voltage. See 5.1.)
23.2 For tubing having a recovered inside diameter of 1 in. (25 mm) or less, choose a mandrel that is slightly larger in diameter
than the fully recovered inside diameter of the tubing to be tested. Heat shrink the specimen onto the mandrel by heating it in an
oven at the specified time and temperature for the tubing being tested.
D2671 − 21
23.2.1 Following the heating, remove the mandrel from the oven and allow it to cool to room temperature. Apply a 1 in. (25.4
mm) wide metal-foil electrode not more than 0.001 in. (0.02 mm) thick around the center of the specimen.
23.3 For tubing having a recovered inside diameter of more than 1 in. (25.4 mm), heat shrink the specimens in an oven without
a mandrel for the time and temperature specified for the tubing being tested. At the end of the heating period, remove the specimens
from the oven, cut lengthwise, and while still warm, lay out flat to form a sheet. Allow to cool to room temperature.
23.4 Immerse the specimens in oil and determine the dielectric breakdown voltage of the shrunk-down specimens using the
method described in Test Method D149. For flat test specimens, use 1-in. (25-mm) (25 mm) electrodes as in Test Method D149,
Table number 1, Electrode Type 2. Make one test on each of the five specimens. Use the short-time test at a rate of rise of 500
V/s.
23.5 For determination of dielectric strength, measure the wall thickness immediately adjacent to the point of dielectric breakdown
of each specimen using the method in 11.2.
23.6 Calculate the dielectric strength by dividing the breakdown voltage by the wall thickness for each specimen.
24. Report
24.1 Report the following information:
24.1.1 Identification of the tubing,
24.1.2 Breakdown voltage in kilovolts for each specimen,
24.1.3 Average breakdown voltage for the five specimens,
24.1.4 Wall thickness of each specimen in inches or millimetres,
24.1.5 Dielectric strength in volts per mil or kilovolts per millimetre for each specimen, and
24.1.6 Average dielectric strength for the five specimens.
25. Precision and Bias
25.1 The overall estimates of the precision within laboratories, (S ) j, and the precision between laboratories, (S )j, are given in
r r
Table 3 for four selected materials. These estimates are based on a round robin of five specimens, each run in six laboratories.
This test method has no bias because the results are expressed purely in terms of this test method.
TABLE 3 Estimated Precision of Tensile Property Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Dielectric breakdown voltage kV PVDF 11.4 1.7 1.8
Polyolefin, semi-rigid 13.3 1.7 2.9
Polyolefin, flexible 19.2 1.6 2.0
Polyolefin, flexible 30 1.9 4.7
Dielectric strength V/mil (kV/mm) Polyolefin, semi-rigid 460 (18.11) 62 (2.44) 110 (4.33)
Polyolefin, flexible 680 (26.77) 39 (1.54) 114 (4.49)
Polyolefin, flexible 850 (33.46) 84 (3.31) 133 (5.24)
PVDF 1100 (43.31) 128 (5.04) 150 (5.90)
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D09-1025. Contact ASTM Customer
Service at [e-mail].
D2671 − 21
HEAT SHOCK
26. Significance and Use
26.1 It is not always possible to control precisely the heat source used to effect shrinkage of tubing, and for this reason, it is
possible that the tubing will be exposed to temperatures in excess of those intended for shrinkage. This test method serves to
evaluate the effects on the tubing of short periods of exposure to specified temperatures in excess of those normally recommended
for shrinkage. This test is a means of obtaining visual evidence of the effects of elevated temperatures on heat-shrinkable tubing
by visual examination, either alone or in combination with a mandrel wrap procedure following the heat exposure.
27. Test Specimens
27.1 Cut three lengths of tubing, each 6 in. (150 mm) long, from the sample of tubing in the expanded state. Cut ⁄2-in. (13-mm)
(13 mm) wide strips from tubing having an expanded diameter greater than 0.5 in. (12.7 mm).
28. Procedure
28.1 Attach a small piece of wire to each specimen so that the specimen is suspended vertically in the oven during the test.
28.2 Place the specimen in an oven similar to that described in 9.4, maintained at a specified temperature. After a period of 4 h,
remove the specimen and allow it to cool to room temperature. When required, wrap the specimen 360° around a metal mandrel
having a diameter as specified in the tubing specification in 2 to 4 s.
28.3 Examine the specimens for evidence of cracking, flowing, or dripping.
29. Report
29.1 Report the following information:
29.1.1 Identification of the tubing,
29.1.2 Temperature of the test, and
29.1.3 Record of cracking, flow, or dripping.
30. Precision and Bias
30.1 No statement is made about either the precision or the bias of this test method for measuring heat shock since the result
merely states whether there is conformance or nonconformance to the criteria specified in the procedure.
STORAGE LIFE
31. Significance and Use
31.1 In the expanded form, heat-shrinkable tubing is under stress. Over a period of time there will be a tendency for this stress
to relax. Potential effects of this relaxation include the following: (a) that the tubing no longer meets the minimum-expanded
dimension, or (b) that it will fail to recover to the maximum-recovered dimension. This test method provides an accelerated means
of evaluating the utility of heat-shrinkable tubing after a period of storage under prescribed conditions and assists in determining
the need for special storage and handling requirements.
32. Test Specimens
32.1 Cut three lengths of tubing, each 6 in. (150 mm) long, from the sample of tubing in the expanded state.
33. Procedure
33.1 Measure the inside diameter of the specimens in accordance with 11.1.
D2671 − 21
33.2 Place the specimens in an oven of the forced-convection type and capable of maintaining a temperature of 40 6 2°C 2 °C
(104 6 4°F) 4 °F) (or other specified temperature) for a period of two weeks.
33.3 Remove the specimens and allow them to cool to room temperature. Measure the inside diameter of each specimen in
accordance with 11.1.
33.4 Shrink the specimens and measure the inside diameter and wall thickness in accordance with 11.1 and 11.2.
34. Report
34.1 Report the following information:
34.1.1 Identification of the tubing,
34.1.2 Inside diameter of the tubing before conditioning, after two weeks of conditioning, and after heat shrinking,
34.1.3 Wall thickness after heat-shrinking, and
34.1.4 Temperature of the storage-life test, if other than 40°C.40 °C.
35. Precision and Bias
35.1 The overall estimates of the precision within laboratories, (S ) j, and the precision between laboratories, (S )j, are given in
r r
Table 4 for two selected materials. These estimates are based on a round robin of three specimens, each run in six laboratories.
This test method has no bias because the results are expressed purely in terms of this test method.
LOW-TEMPERATURE PROPERTIES
36. Significance and Use
36.1 Flexibility of tubing at low temperatures is an important service property. Procedures A and C are low-temperature flexibility
tests. Procedure A serves to evaluate tubing by a method that simulates actual use in service, but that is restricted by its physical
limitations to tubing having a recovered inside diameter of less than 0.375 in. (9.5 mm). Procedure C can be used on any size tubing
and the test can be performed on tubing in either the expanded or fully recovered condition. Alternatively, a brittleness temperature
test (Procedure B) serves to evaluate low-temperature impact resistance of specimens of prescribed form and is not restricted to
certain sizes.
37. Apparatus
37.1 Cold Chamber—A thermally insulated enclosure equipped to maintain an atmosphere at a specified low temperature to within
62°C, 62 °C, and of such size as to permit convenient bending of specimens around mandrels without removal from the chamber.
37.2 Stranded Wire, sizes AWG 0 to 30 (9.5 to 0.25 mm).
37.3 Mandrels, stainless steel. Sizes are to be specified in tubing specification.
TABLE 4 Estimated Precision of Storage Life Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Expanded inside diameter in. (mm) PVC 0.26 (6.60) 0.005 (0.127) 0.011 (0.279)
Polychloroprene 0.95 (24.13) 0.002 (0.051) 0.012 (0.305)
Recovered inside diameter in. (mm) PVC 0.12 (3.05) 0.002 (0.051) 0.004 (0.102)
Polychloroprene 0.43 (10.92) 0.002 (0.051) 0.008 (0.203)
Recovered wall in. (mm) PVC 0.023 (0.584) 0.0011 (0.028) 0.0019 (0.048)
Polychloroprene 0.064 (1.626) 0.0011 (0.028) 0.0031 (0.079)
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38. Test Specimens
38.1 Procedure A—Cut three lengths of tubing, each 18 in. (460 mm) long, from the sample of tubing in the expanded state.
38.2 Procedure B—Cut ten 1.5-in. (38-mm) (38 mm) lengths of tubing from the sample of tubing in the recovered (shrunk) state.
For tubing of inside diameter 0.148 in. (3.76 mm) or less, specimens are to be in full-section form; for tubing of inside diameter
greater than 0.148 in., specimens are to be in the form of strips 0.25 in. (6.4 mm) wide by 1.5 in. long.
38.3 Procedure C—Cut three specimens each 12 in. (300 mm) (300 mm) long from the sample. For tubing having a recovered
diameter greater than 0.4 in. (10 mm) the specimens shall be ⁄4-in. (6.4-mm) (6.4 mm) wide strips cut from the 12-in. length of
tubing.
NOTE 6—Because no flexible mandrel is readily available that can be conveniently used to test tubing of inside diameter greater than AWG 0 (10 mm),
Procedure A is restricted to tubing of inside diameter in the recovered state of less than 0.40 in. (10 mm).
39. Procedure A—Low-TemperatureA—Low-temperature Flexibility
39.1 Select a stranded wire that is the nearest AWG size which is larger than the specified fully recovered diameter of the specimen
being tested. See Table 5 for stranded wire sizes suitable for use with common fractional inch tubing sizes.
39.2 Locate the specimen centrally on a 24-in. (610-mm) (610 mm) length of stranded wire and heat shrink the tubing in
accordance with 11.1.3.
39.3 Condition the specimens in the cold chamber for a period of 1 h at the specified temperature along with mandrels of the
specified diameter.
39.4 After the conditioning period, and while at the specified low temperature, and without removing the specimens from the
chamber, bend the tubing around the mandrel for not less than one complete wrap (360°) at a uniform speed of 10 6 2 s per wrap.
39.5 Remove the specimens and the mandrels from the cold chamber and immediately examine them for evidences of cracking
of the tubing.
40. Procedure B—Brittleness Temperature
40.1 Using Procedure A of Test Method D746, conduct brittleness temperature tests at a specified low temperature.
41. Procedure C—Low-TemperatureC—Low-temperature Flexibility
41.1 Condition the specimens in the cold chamber for 4 h at the specified temperature along with mandrels of the specified
diameter.
TABLE 5 Stranded Wire Flexible Mandrel Sizes for Procedure A
Low-TemperatureLow-temperature Flexibility
Specified Diameter of Recovered Tubing,
AWG Wire Size
in. (mm)
0.023 (0.59) 24
0.031 (0.76) 22
0.047 (1.16) 18
0.062 (1.60) 14
0.093 (2.34) 10
0.125 (3.18) 8
0.187 (4.75) 6
0.250 (6.35) 4
0.312 (7.92) 2
0.375 (9.53) 0
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41.2 Upon completion of this conditioning and at this same temperature, wrap the specimens not less than 360° about the mandrel
in approximately 10 6 2 s. Visually examine the specimens for cracks after removal from the cold chamber.
42. Report
42.1 Report the following information on low-temperature flexibility (Procedure A):
42.1.1 Identification of the tubing,
42.1.2 Specified inside diameter of the tubing specimens,
42.1.3 Size of the wire used,
42.1.4 Size of the mandrel used,
42.1.5 Temperature of the cold chamber, and
42.1.6 Record of cracking of the tubing after flexing.
42.2 Report the following information on brittleness temperature (Procedure B):
42.2.1 Identification of the tubing,
42.2.2 Form of the specimens tested,
42.2.3 Temperature of the cold chamber, and
42.2.4 Number of specimens failed.
42.3 Report the following information on low-temperature flexibility (Procedure C):
42.3.1 Identification of the tubing,
42.3.2 Nominal size of the tubing,
42.3.3 Size of the mandrel used,
42.3.4 Temperature of the cold chamber, and
42.3.5 Record of cracking of the tubing after wrapping.
43. Precision and Bias
43.1 No statement is made about either the precision or the bias of this test method for measuring low-temperature properties since
the result merely states whether there is conformance or nonconformance to the criteria specified in the procedure.
TENSILE STRENGTH AND ULTIMATE ELONGATION
44. Test Specimens
44.1 For tubing of recovered inside diameter not greater than 0.33 in. (8.4 mm), cut five lengths, each 4 in. (100 mm) long, from
the tubing in the recovered state.
44.2 For tubing of recovered inside diameter greater than 0.33 in. (8.4 mm), prepare five specimens from tubing in the recovered
state by die cutting in accordance with Test Methods D412, with the long dimension of the die parallel to the longitudinal axis of
the tubing.
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44.2.1 Prepare elastomeric and flexible plastic tubing with a secant modulus of up to 25 000 psi in the form of Die C of Test
Methods D412.
44.2.2 Prepare all other plastic tubing in the form of Die D of Test Methods D412.
45. Procedure
45.1 For use in determining elongation, mark two parallel gage lines on the tubing or die specimens, 1 in. (25 mm) apart and
centrally located on the specimen. Alternatively, make this measurement with an extensiometer apparatus.
45.2 For purposes of calculating tensile strength, measure the inside diameter and wall thickness of the specimens in accordance
with the methods in 11.1 and 11.2, selecting those measurements which will provide the minimum cross-sectional area for each
specimen.
45.3 For elastomeric and flexible tubing (44.2.1), set the grips of the testing machine 2 in. (50 mm) apart for tubing specimens
and 2.5 in. (65 mm) for die cut specimens, and locate the specimens so that the bench marks are centrally spaced between the grips.
45.4 For all other tubing (44.2.2), perform the test as in Section 45 using grips spaced 1 in. (25 mm) apart.
45.5 Determine the breaking force and ultimate elongation in accordance with Test Methods D412, except use a rate of jaw
separation as specified in the tubing specification for the material being tested. Retest any specimen that breaks outside the bench
marks.
45.6 A retest is not required for specimens that break outside the benchmark when (1) the actual value of elongation is not required
(for example, in a pass-fail quality control application) and (2) the minimum specified value is achieved prior to break.
46. Calculation
46.1 Calculate the tensile strength and ultimate elongation in accordance with Test Methods D412.
47. Report
47.1 Report the following information:
47.1.1 Identification of tubing,
47.1.2 Rate of jaw separation used,
47.1.3 Individual and averaged values for tensile strength in pounds-force per square inch (megapascals), and
47.1.4 Individual and averaged values for ultimate elongation in percent.
48. Precision and Bias
48.1 The overall estimates of the precision within laboratories, (S ) j, and the precision between laboratories, (S )j, are given in
r r
Table 6for four selected materials. These estimates are based on a round robin of five specimens, each run in six laboratories. No
bias statement can be made due to the lack of a standard reference material.
HEAT RESISTANCE
49. Significance and Use
49.1 The reduction of tensile strength or ultimate elongation due to exposure to elevated temperatures is indicative of loss of
volatile constituents or of chemical changes in the tubing. The specified temperature is sufficiently high to permit the use of a
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TABLE 6 Estimated Precision of Dielectric Property Measurements for Selected Tubings
(S )j Estimate of (S )j Estimate of
r R
Property Units Generic Type Nominal Value Precision Within Precision Between
Laboratories Laboratories
Tensile strength psi (MPa) Polyolefin, flexible 1600 (11.0) 70 (0.48) 100 (0.69)
Polychloroprene 1700 (11.7) 60 (0.41) 150 (1.03)
Polyolefin, semi-rigid 2300 (15.9) 110 (0.76) 260 (1.79)
PVC 3100 (21.4) 130 (0.90) 260 (1.79)
Ultimate elongation % PVC 270 30 30
Polyolefin, flexible 370 20 20
Polyolefin, semi-rigid 410 30 40
Polychloroprene 430 20 50
Stress modulus (tensile stress) at 200 % psi (MPa) Polychloroprene 870 (6.0) 40 (0.28) 110 (0.76)
PTFE 5500 (37.9) 600 (4.14) 670 (4.62)
TABLE 7 Estimated Precision for Heat Resistance Property Measurements for Four Tubings
Property Units Tubing Type Nominal Value (S ) (S )
r j R j
Tensile strength psi (MPa) Polyolefin, flexible whole tube specimen 2260 (15.6) 117 (0.81) 156 (1.08)
Polyolefin, flexible die cut specimen 2220 (15.3) 84 (0.58) 183 (1.26)
PVC 3130 (21.6) 68 (0.47) 155 (1.07)
Polychloroprene 1610 (11.1) 53 (0.37) 70 (0.48)
Ultimate elongation % Polyolefin, flexible whole tube specimen 320 19 25
Polyolefin, flexible die cut specimen 380 16 32
PVC 220 18 35
Polychloroprene 340 19 26
relatively short exposure period so that the test is suitable as an acceptance test for process control. Longer exposure times at other
temperatures are potentially desirable for research purposes.
50. Apparatus
50.1 Oven, forced-convection type with an air velocity of between 100 and 200 ft/min (0.5 and 1 m/s), capable of maintaining
temperature within 62.5°C.62.5 °C.
51. Test Specimens
51.1 Prepare five specimens in accordance with Section 44.
52. Procedure
52.1 Suspend the specimens in the oven for a specified period of time and at the selected temperature.
52.2 Remove the specimens, allow them to cool to room temperature, and determine the tensile strength and ultimate elongation
as required in accordance with Sections 44 to 47, disregarding any change in color of the specimens after heat aging.
53. Report
53.1 Report the following information:
53.1.1 Identification of the tubing,
53.1.2 Oven temperature,
53.1.3 Period of exposure to heat,
53.1.4 Tensile strength in pounds-force per square inch (megapascals) for the aged specimens when required together with the
value reported in 47.1.3, and
53.1.5 Ultimate elongation, in percent, for the aged specimens, together with the value repor
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