ASTM D2412-21

Standard Test Method for Determination of External Loading Characteristics of Plastic Pipe by Parallel-Plate Loading

SIGNIFICANCE AND USE
5.1 The external loading properties of plastic pipe obtained by this test method are used for the following:  
5.1.1 To determine the stiffness of the pipe. This is a function of the pipe dimensions and the physical properties of the material of which the pipe is made.  
5.1.2 To determine the load-deflection characteristics and pipe stiffness which are used for engineering design (see Appendix X1).  
5.1.3 To compare the characteristics of various plastics in pipe form.  
5.1.4 To study the interrelations of dimensions and deflection properties of plastic pipe and conduit.  
5.1.5 To measure the deflection and load-resistance at any of several significant events if they occur during the test.
SCOPE
1.1 This test method covers the determination of load-deflection characteristics of plastic pipe under parallel-plate loading.  
1.2 This test method covers thermoplastic resin pipe, reinforced thermosetting resin pipe (RTRP), and reinforced polymer mortar pipe (RPMP).  
1.3 The characteristics determined by this test method are pipe stiffness, stiffness factor, and load at specific deflections.  
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
Note 1: While this test method can be used in measuring the pipe stiffness of corrugated plastic pipe or tubing, other profile wall designs, and products produced from polyethylene, PVC or polypropylene, special conditions and procedures are used. These details are included in the product standards, for example, Specifications F667/F667M, F949, F2764/F2764M, and others.  
1.5 The text of this test method references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the test method.  
1.6 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.  
1.7 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-Jan-2021
• ICS: 23.040.20 - Plastics pipes
• Technical Committee: F17 - Plastic Piping Systems
• Drafting Committee: F17.40 - Test Methods

Relations

• Refers: ASTM F412-20 - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 01-Apr-2020
• Refers: ASTM F949-20 - Standard Specification for Poly(Vinyl Chloride) (PVC) Corrugated Sewer Pipe With a Smooth Interior and Fittings
• Effective Date: 15-Feb-2020
• Refers: ASTM F949-15(2019) - Standard Specification for Poly(Vinyl Chloride) (PVC) Corrugated Sewer Pipe With a Smooth Interior and Fittings
• Effective Date: 01-Aug-2019
• Refers: ASTM F412-19 - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 01-Jan-2019
• Refers: ASTM F2764/F2764M-18a - Standard Specification for 6 to 60 in. [150 to 1500 mm] Polypropylene (PP) Corrugated Double and Triple Wall Pipe and Fittings for Non-Pressure Sanitary Sewer Applications
• Effective Date: 01-Nov-2018
• Refers: ASTM F2764/F2764M-18 - Standard Specification for 6 to 60 in. [150 to 1500 mm] Polypropylene (PP) Corrugated Double and Triple Wall Pipe and Fittings for Non-Pressure Sanitary Sewer Applications
• Effective Date: 01-Oct-2018
• Refers: ASTM D1600-18 - Standard Terminology for Abbreviated Terms Relating to Plastics (Withdrawn 2024)
• Effective Date: 01-Jan-2018
• Refers: ASTM F412-17a - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 01-Aug-2017
• Refers: ASTM F2764/F2764M-17 - Standard Specification for 6 to 60 in. [150 to 1500 mm] Polypropylene (PP) Corrugated Double and Triple Wall Pipe and Fittings for Non-Pressure Sanitary Sewer Applications
• Effective Date: 01-Apr-2017
• Refers: ASTM F2764/F2764M-17e1 - Standard Specification for 6 to 60 in. [150 to 1500 mm] Polypropylene (PP) Corrugated Double and Triple Wall Pipe and Fittings for Non-Pressure Sanitary Sewer Applications
• Effective Date: 01-Apr-2017
• Refers: ASTM F412-17 - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 01-Feb-2017
• Refers: ASTM F412-16a - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 15-Nov-2016
• Refers: ASTM F412-16 - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 01-Aug-2016
• Refers: ASTM F2764/F2764M-16 - Standard Specification for 6 to 60 in. [150 to 1500 mm] Polypropylene (PP) Corrugated Double and Triple Wall Pipe and Fittings for Non-Pressure Sanitary Sewer Applications
• Effective Date: 01-Aug-2016
• Refers: ASTM F412-15 - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 01-Jun-2015

Overview

ASTM D2412-21: Standard Test Method for Determination of External Loading Characteristics of Plastic Pipe by Parallel-Plate Loading specifies procedures for measuring the load-deflection properties of plastic pipes. This standard, issued by ASTM International, is essential for evaluating the stiffness and mechanical performance of various types of plastic piping, including thermoplastic resin pipe, reinforced thermosetting resin pipe (RTRP), and reinforced polymer mortar pipe (RPMP). The test method involves compressing a pipe section between two parallel plates to assess how it deforms under controlled loading conditions, a critical parameter for engineering design and quality assurance in plastic pipe manufacturing and installation.

Key Topics

• Pipe Stiffness: Determined by measuring a pipe’s resistance to deformation under load, factoring in dimensions and material properties.
• Load-Deflection Characteristics: Analysis of how the pipe responds to applied loads, which provides crucial data for structural integrity assessments.
• Comparison Across Materials: Facilitates direct comparison of mechanical performance among different plastic pipe materials and designs.
• Deflection Event Measurement: Records significant events such as liner cracking, wall cracking, delamination, or rupture during testing, aiding in comprehensive pipe evaluation.
• Reporting: The method sets out detailed requirements for reporting specimen dimensions, observed events, and calculated values, ensuring transparency and reproducibility.

Applications

ASTM D2412-21 is widely applied in the plastics and piping industries for a range of practical purposes:

• Engineering Design: Provides foundational data for calculating pipe deflection under external loads, supporting safe and effective underground or above-ground pipe installations.
• Quality Control: Used in manufacturing environments to verify the structural stiffness and load-resistance of production batches, ensuring compliance with industry requirements.
• Material and Product Comparison: Supports material selection by allowing engineers and specifiers to compare performance characteristics of pipes made from different plastics or different designs (e.g., corrugated, smooth wall).
• Conduit and Infrastructure Projects: Essential for civil engineering projects involving underground utilities, stormwater management, sanitary sewer systems, and non-pressure applications.
• Research and Development: Aids in studying relationships between pipe geometry, material formulation, and mechanical behavior to innovate more durable piping systems.

This test method is suitable for pipes made from polyethylene, PVC, polypropylene, and reinforced composites, provided any special conditions outlined in appropriate product standards are applied.

Related Standards

For comprehensive evaluation and compatibility with ASTM D2412-21, several related ASTM standards and specifications are frequently referenced:

• ASTM D695: Test Method for Compressive Properties of Rigid Plastics
• ASTM D2122: Test Method for Determining Dimensions of Thermoplastic Pipe and Fittings
• ASTM F412: Terminology Relating to Plastic Piping Systems
• ASTM F405/F667/F667M: Specification for Corrugated Polyethylene (PE) Pipe and Fittings (withdrawn)
• ASTM F949: Specification for PVC Corrugated Sewer Pipe with a Smooth Interior and Fittings
• ASTM F2764/F2764M: Specification for Polypropylene (PP) Corrugated Pipe for Sanitary Sewer Applications

These standards collectively support a framework for consistency in testing plastic piping systems, ensuring reliable and repeatable results across different products and projects.

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Keywords: ASTM D2412-21, external loading, plastic pipe, parallel-plate test, pipe stiffness, load-deflection, pipe testing, piping system standards, engineering design, material comparison, quality control, pipe deflection.

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: D2412 − 21
Standard Test Method for
Determination of External Loading Characteristics of Plastic
Pipe by Parallel-Plate Loading
This standard is issued under the fixed designation D2412; 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* 2. Referenced Documents
1.1 This test method covers the determination of load- 2.1 ASTM Standards:
deflection characteristics of plastic pipe under parallel-plate D695 Test Method for Compressive Properties of Rigid
loading. Plastics
D1600 Terminology forAbbreviatedTerms Relating to Plas-
1.2 This test method covers thermoplastic resin pipe, rein-
tics
forced thermosetting resin pipe (RTRP), and reinforced poly-
D2122 Test Method for Determining Dimensions of Ther-
mer mortar pipe (RPMP).
moplastic Pipe and Fittings
1.3 The characteristics determined by this test method are
E177 Practice for Use of the Terms Precision and Bias in
pipe stiffness, stiffness factor, and load at specific deflections.
ASTM Test Methods
1.4 The values stated in inch-pound units are to be regarded E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only F412 Terminology Relating to Plastic Piping Systems
F667/F667M Specification for 3 through 24 in. Corrugated
and are not considered standard.
Polyethylene Pipe and Fittings
NOTE 1—While this test method can be used in measuring the pipe
F949 Specification for Poly(Vinyl Chloride) (PVC) Corru-
stiffness of corrugated plastic pipe or tubing, other profile wall designs,
gated Sewer Pipe With a Smooth Interior and Fittings
and products produced from polyethylene, PVC or polypropylene, special
conditions and procedures are used. These details are included in the F2764/F2764M Specification for 6 to 60 in. [150 to 1500
product standards, for example, Specifications F667/F667M, F949,
mm] Polypropylene (PP) Corrugated Double and Triple
F2764/F2764M, and others.
Wall Pipe and Fittings for Non-Pressure Sanitary Sewer
1.5 The text of this test method references notes and
Applications
footnotes that provide explanatory material. These notes and
footnotes (excluding those in tables and figures) shall not be
3. Terminology
considered as requirements of the test method.
3.1 Definitions—Definitions are in accordance with Termi-
1.6 This standard does not purport to address all of the
nology F412, and abbreviations are in accordance with Termi-
safety concerns, if any, associated with its use. It is the
nology D1600, unless otherwise specified.
responsibility of the user of this standard to establish appro-
3.2 Definitions of Terms Specific to This Standard:
priate safety, health, and environmental practices and deter-
3.2.1 ∆y—measured change of the inside diameter in the
mine the applicability of regulatory limitations prior to use.
direction of load application expressed in inches (millimetres).
1.7 This international standard was developed in accor-
3.2.2 initial inside diameter (d)—the average of the inside
dance with internationally recognized principles on standard-
diameters as determined for the several test specimens and
ization established in the Decision on Principles for the
expressed in inches (millimetres).
Development of International Standards, Guides and Recom-
3.2.3 load (F)—the load applied to the pipe to produce a
mendations issued by the World Trade Organization Technical
givenpercentagedeflection.Expressedasnewtonspermetreor
Barriers to Trade (TBT) Committee.
pounds-force per linear inch.
This test method is under the jurisdiction of ASTM Committee F17 on Plastic
Piping Systems and is the direct responsibility of Subcommittee F17.40 on Test
Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2021. Published February 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1965. Last previous edition approved in 2018 as D2412 – 11(2018). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D2412-21. 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
D2412 − 21
3.2.4 mean radius (r)—the mid-wall radius determined by used to make the tests. The rate of head approach shall be 0.50
subtractingtheaveragewallthicknessfromtheaverageoutside 6 0.02 in. (12.5 6 0.5 mm)/min.
diameter and dividing the difference by two. Expressed as
NOTE 4—Hydraulic testing machines that may vary slightly from these
inches (millimetres).
rate limits are commonly used and are satisfactory for testing RTRP and
RPMP pipe 24-in. (610-mm) size and larger.
3.2.5 pipe deflection (P)—the ratio of the reduction in pipe
inside diameter to the initial inside diameter expressed as the
6.2 Loading Plates—The load shall be applied to the speci-
percentage of the initial inside diameter.
men through two parallel steel bearing plates. The plates shall
be flat, smooth, and clean. The thickness of the plates shall be
3.2.6 pipe significant events:
sufficient so that no bending or deformation occurs during the
3.2.6.1 liner cracking or crazing—the occurrence of a break
test, but it shall not be less than 0.25 in. (6.0 mm). The plate
or network of fine breaks in the liner visible to the unaided eye.
length shall equal or exceed the specimen length and the plate
3.2.6.2 rupture—a crack or break extending entirely or
width shall not be less than the pipe contact width at maximum
partly through the pipe wall.
pipe deflection plus 6.0 in. (150 mm).
NOTE 2—The significant events listed may or may not occur in a
specific pipe material.
NOTE 5—For some types of testing machines a greater plate thickness
may be required to limit plate bending.
3.2.6.3 wall cracking—the occurence of a break in the pipe
wall visible to the unaided eye. 6.3 Deformation (Deflection) Indicator— The change in
inside diameter, or deformation parallel to the direction of
3.2.6.4 wall delamination—theoccurrenceofanyseparation
in the components of the pipe wall visible to the unaided eye. loading, shall be measured with a suitable instrument meeting
the requirements of Test Method D695, except that the instru-
3.2.7 pipe stiffness (PS)—the value obtained by dividing the
force per unit length of specimen by the resulting deflection in ment shall be accurate to the nearest 0.010 in. (0.25 mm). The
instrument shall not support the pipe test specimen or the plate
the same units at the prescribed percentage deflection.
or affect in any way the load deflection measurements.
3.2.8 stiffness factor (SF)—the product of pipe stiffness and
3 Changes in diameter are measured during loading by continu-
the quantity 0.149 r .
ously recording plate travel or by periodically computing it.
3.2.9 Discussion—The“pipestiffness”and“stiffnessfactor”
are related as follows:
7. Test Specimens
PS 5F/∆y (1)
7.1 For thermoplastic pipe, the test specimen shall be a
3 3
SF 5 EI 5 0.149 Fr /∆y 5 0.149 r ~PS! (2) 1
piece of pipe 6 6 ⁄8 in. (150 6 3 mm) long.
NOTE 3—See Appendix X2 for information relating PS, E, and ∆y.
7.2 For reinforced thermosetting resin pipe, the minimum
test specimen length shall be three times the nominal pipe
4. Summary of Test Method
diameter or 12.0 in. (300 mm), whichever is smaller. For pipe
4.1 A short length of pipe is loaded between two rigid
larger than 60 in. (1524 mm) in diameter, the minimum
parallel flat plates at a controlled rate of approach to one
specimen length shall be 20 % of the nominal diameter
another. Load-deflection (of the pipe diameter) data are ob-
adjusted to the nearest 1 in. (25.4 mm).
tained. If cracking, crazing, delamination, or rupture occurs,
the corresponding load and deflection are recorded. 7.3 The ends of specimens shall be cut square and shall be
free of burrs and jagged edges.
5. Significance and Use
7.4 No less than three specimens shall be tested for each
5.1 The external loading properties of plastic pipe obtained
sample of pipe.
by this test method are used for the following:
NOTE6—Forqualitycontroltestingasinglespecimenmaybeusedwith
5.1.1 To determine the stiffness of the pipe. This is a
the thinnest wall at the top.
function of the pipe dimensions and the physical properties of
7.5 Certain RTRP pipes exhibit surface irregularity because
the material of which the pipe is made.
the production process is inside diameter controlled. To assure
5.1.2 To determine the load-deflection characteristics and
accurate test results by parallel-plate loading, the test specimen
pipe stiffness which are used for engineering design (see
must be uniformly loaded along its entire bearing surface. If
Appendix X1).
surface irregularities (resin-rich areas) along the outside diam-
5.1.3 To compare the characteristics of various plastics in
eter prevent the bearing load from being uniformly distributed
pipe form.
along the length of the specimen, the outside surface along the
5.1.4 To study the interrelations of dimensions and deflec-
loading line shall be sanded smooth by hand. This sanding
tion properties of plastic pipe and conduit.
shall only be done if the reinforcement is not damaged. Note
5.1.5 Tomeasurethedeflectionandload-resistanceatanyof
that sanding shall be done only along the plate contact lines.
several significant events if they occur during the test.
8. Conditioning
6. Apparatus
6.1 Testing Machine—A properly calibrated compression 8.1 Condition pipe for at least4hinair,ata temperature of
testing machine of the constant-rate-of-crosshead movement 73.4 6 3.6 °F (23 6 2 °C), and conduct the test in a room
type meeting the requirements of Test Method D695 shall be maintained at the same temperature.
D2412 − 21
8.2 When a referee test is required, condition specimens for 9.4 Compressthespecimenataconstantrateof0.50 60.02
at least 40 h at 73.4 6 3.6 °F (23 6 2 °C) and 50 6 5% in. (12.5 6 0.5 mm)/min.
relative humidity and conduct the test under the same condi-
NOTE 8—For larger sizes of pipe made from relatively low-modulus
tions.
materials, creep may affect the results of this test because of the loading
rate specified.
9. Procedure
9.5 Record load-deflection measurements continuously or
9.1 Make the following measurements on each specimen:
intermittently with reference to the relative movement of the
9.1.1 Determine the length of each specimen to the nearest
bearing plates. If measurements are made intermittently, make
⁄32 in. (1 mm) or better, by making and averaging at least four
and record such measurements at increments of not more than
equally spaced measurements around the perimeter.
5 % of the average inside diameter of the specimen. Refer to
9.1.2 Measure the wall thickness of each specimen in
Annex A1.
accordance with Test Method D2122. Make at least eight
9.6 Observe and note the load and deflection at the first
measurements equally spaced around one end and calculate the
evidence of each of the following significant events when and
average wall thickness.
if they occur:
9.1.3 Determine whether a line of minimum wall thickness
9.6.1 Liner cracking or crazing.
exists along the length of the specimen and if so mark it for use
9.6.2 Wall cracking.
in 9.2.1.
9.6.3 Wall delamination.
NOTE7—OnRTRPandRPMPpipemeasurementsmaybemadeatboth
9.6.4 Rupture.
ends.
9.7 Record type and position of each event with respect to
9.1.4 Determine the average outside diameter to the nearest
the corresponding load and deflection. Discontinue the test
0.01 in. (0.2 mm) using a circumferential wrap tape or by
when either of the following occur:
averaging the maximum and minimum outside diameters as
9.7.1 The load on the specimen fails to increase with
measured with a micrometer or caliper.
increasing deflection (maximum point on load-deflection plot
9.1.5 For OD-controlled pipe calculate the average pipe
has been reached).
insidediameter(ID)bysubtractingtwotimestheaverageofall
9.7.2 The specimen deflection reaches 30 % of the average
wall thicknesses (9.1.2) from the average of all outside
inside diameter or the required maximum deflection.
diameters (9.1.4). For ID-controlled pipe determine the aver-
age ID by measuring the maximum and minimum inside
10. Calculation
diameters. Use this average ID as the basis for computing the
10.1 Calculate the pipe stiffness, PS, for any given deflec-
percentage of deflection for all specimens in that lot of pipe.
tion as follows:
9.2 Locatethepipesectionwithitslongitudinalaxisparallel
PS 5F/∆y lbf/in./in. ~kPa! (3)
to the bearing plates and center it laterally in the testing
NOTE 9—Refer to Appendix X3 for additional information on units.
machine
...

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: D2412 − 11 (Reapproved 2018) D2412 − 21
Standard Test Method for
Determination of External Loading Characteristics of Plastic
Pipe by Parallel-Plate Loading
This standard is issued under the fixed designation D2412; 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 This test method covers the determination of load-deflection characteristics of plastic pipe under parallel-plate loading.
1.2 This test method covers thermoplastic resin pipe, reinforced thermosetting resin pipe (RTRP), and reinforced polymer mortar
pipe (RPMP).
1.3 The characteristics determined by this test method are pipe stiffness, stiffness factor, and load at specific deflections.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
NOTE 1—While this test method can be used in measuring the pipe stiffness of corrugated plastic pipe or tubing, other profile wall designs, and products
produced from polyethylene, PVC or polypropylene, special conditions and procedures are used. These details are included in the product standards, for
example, SpecificationSpecifications F405F667/F667M., F949, F2764/F2764M, and others.
1.5 The text of this test method references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the test method.
1.6 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.
1.7 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:
D695 Test Method for Compressive Properties of Rigid Plastics
D1600 Terminology for Abbreviated Terms Relating to Plastics
This test method is under the jurisdiction of ASTM Committee F17 on Plastic Piping Systems and is the direct responsibility of Subcommittee F17.40 on Test Methods.
Current edition approved June 1, 2018Feb. 1, 2021. Published July 2018February 2021. Originally approved in 1965. Last previous edition approved in 20112018 as
D2412 – 11.D2412 – 11(2018). DOI: 10.1520/D2412-11R18.10.1520/D2412-21.
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.
*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
D2412 − 21
D2122 Test Method for Determining Dimensions of Thermoplastic Pipe and Fittings
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F412 Terminology Relating to Plastic Piping Systems
F405F667/F667M Specification for 3 through 24 in. Corrugated Polyethylene (PE) Pipe and Fittings (Withdrawn 2015)
F949 Specification for Poly(Vinyl Chloride) (PVC) Corrugated Sewer Pipe With a Smooth Interior and Fittings
F412F2764/F2764M Terminology Relating to Plastic Piping SystemsSpecification for 6 to 60 in. [150 to 1500 mm]
Polypropylene (PP) Corrugated Double and Triple Wall Pipe and Fittings for Non-Pressure Sanitary Sewer Applications
3. Terminology
3.1 Definitions—Definitions are in accordance with Terminology F412, and abbreviations are in accordance with Terminology
D1600, unless otherwise specified.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 Δy—measured change of the inside diameter in the direction of load application expressed in inches (millimetres).
3.2.2 initial inside diameter (d)—the average of the inside diameters as determined for the several test specimens and expressed
in inches (millimetres).
3.2.3 load (F)—the load applied to the pipe to produce a given percentage deflection. Expressed as newtons per metre or
pounds-force per linear inch.
3.2.4 mean radius (r)—the mid-wall radius determined by subtracting the average wall thickness from the average outside
diameter and dividing the difference by two. Expressed as inches (millimetres).
3.2.5 pipe deflection (P)—the ratio of the reduction in pipe inside diameter to the initial inside diameter expressed as the
percentage of the initial inside diameter.
3.2.6 pipe significant events:
3.2.6.1 liner cracking or crazing—the occurrence of a break or network of fine breaks in the liner visible to the unaided eye.
3.2.6.2 rupture—a crack or break extending entirely or partly through the pipe wall.
NOTE 2—The significant events listed may or may not occur in a specific pipe material.
3.2.6.3 wall cracking—the occurence of a break in the pipe wall visible to the unaided eye.
3.2.6.4 wall delamination—the occurrence of any separation in the components of the pipe wall visible to the unaided eye.
3.2.7 pipe stiffness (PS)—the value obtained by dividing the force per unit length of specimen by the resulting deflection in the
same units at the prescribed percentage deflection.
3.2.8 stiffness factor (SF)—the product of pipe stiffness and the quantity 0.149 r .
3.2.9 Discussion—The “pipe stiffness” and “stiffness factor” are related as follows:
PS 5 F/Δy (1)
3 3
SF 5 EI 5 0.149 Fr /Δy 5 0.149 r PS (2)
~ !
NOTE 3—See Appendix X2 for information relating PS, E, and Δy.
D2412 − 21
4. Summary of Test Method
4.1 A short length of pipe is loaded between two rigid parallel flat plates at a controlled rate of approach to one another.
Load-deflection (of the pipe diameter) data are obtained. If cracking, crazing, delamination, or rupture occurs, the corresponding
load and deflection are recorded.
5. Significance and Use
5.1 The external loading properties of plastic pipe obtained by this test method are used for the following:
5.1.1 To determine the stiffness of the pipe. This is a function of the pipe dimensions and the physical properties of the material
of which the pipe is made.
5.1.2 To determine the load-deflection characteristics and pipe stiffness which are used for engineering design (see Appendix X1).
5.1.3 To compare the characteristics of various plastics in pipe form.
5.1.4 To study the interrelations of dimensions and deflection properties of plastic pipe and conduit.
5.1.5 To measure the deflection and load-resistance at any of several significant events if they occur during the test.
6. Apparatus
6.1 Testing Machine—A properly calibrated compression testing machine of the constant-rate-of-crosshead movement type
meeting the requirements of Test Method D695 shall be used to make the tests. The rate of head approach shall be 0.50 6 0.02
in. (12.5 6 0.5 mm)/min.
NOTE 4—Hydraulic testing machines that may vary slightly from these rate limits are commonly used and are satisfactory for testing RTRP and RPMP
pipe 24-in. (610-mm) size and larger.
6.2 Loading Plates—The load shall be applied to the specimen through two parallel steel bearing plates. The plates shall be flat,
smooth, and clean. The thickness of the plates shall be sufficient so that no bending or deformation occurs during the test, but it
shall not be less than 0.25 in. (6.0 mm). The plate length shall equal or exceed the specimen length and the plate width shall not
be less than the pipe contact width at maximum pipe deflection plus 6.0 in. (150 mm).
NOTE 5—For some types of testing machines a greater plate thickness may be required to limit plate bending.
6.3 Deformation (Deflection) Indicator— The change in inside diameter, or deformation parallel to the direction of loading, shall
be measured with a suitable instrument meeting the requirements of Test Method D695, except that the instrument shall be accurate
to the nearest 0.010 in. (0.25 mm). The instrument shall not support the pipe test specimen or the plate or affect in any way the
load deflection measurements. Changes in diameter are measured during loading by continuously recording plate travel or by
periodically computing it.
7. Test Specimens
7.1 For thermoplastic pipe, the test specimen shall be a piece of pipe 6 6 ⁄8 in. (150 6 3 mm) long.
7.2 For reinforced thermosetting resin pipe, the minimum test specimen length shall be three times the nominal pipe diameter or
12.0 in. (300 mm), whichever is smaller. For pipe larger than 60 in. (1524 mm) in diameter, the minimum specimen length shall
be 20 % of the nominal diameter adjusted to the nearest 1 in. (25.4 mm).
7.3 The ends of specimens shall be cut square and shall be free of burrs and jagged edges.
7.4 No less than three specimens shall be tested for each sample of pipe.
NOTE 6—For quality control testing a single specimen may be used with the thinnest wall at the top.
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7.5 Certain RTRP pipes exhibit surface irregularity because the production process is inside diameter controlled. To assure
accurate test results by parallel-plate loading, the test specimen must be uniformly loaded along its entire bearing surface. If surface
irregularities (resin-rich areas) along the outside diameter prevent the bearing load from being uniformly distributed along the
length of the specimen, the outside surface along the loading line shall be sanded smooth by hand. This sanding shall only be done
if the reinforcement is not damaged. Note that sanding shall be done only along the plate contact lines.
8. Conditioning
8.1 Condition pipe for at least 4 h in air, at a temperature of 73.4 6 3.6 °F (23 6 2 °C), and conduct the test in a room maintained
at the same temperature.
8.2 When a referee test is required, condition specimens for at least 40 h at 73.4 6 3.6 °F (23 6 2 °C) and 50 6 5 % relative
humidity and conduct the test under the same conditions.
9. Procedure
9.1 Make the following measurements on each specimen:
9.1.1 Determine the length of each specimen to the nearest ⁄32 in. (1 mm) or better, by making and averaging at least four equally
spaced measurements around the perimeter.
9.1.2 Measure the wall thickness of each specimen in accordance with Test Method D2122. Make at least eight measurements
equally spaced around one end and calculate the average wall thickness.
9.1.3 Determine whether a line of minimum wall thickness exists along the length of the specimen and if so mark it for use in
9.2.1.
NOTE 7—On RTRP and RPMP pipe measurements may be made at both ends.
9.1.4 Determine the average outside diameter to the nearest 0.01 in. (0.2 mm) using a circumferential wrap tape or by averaging
the maximum and minimum outside diameters as measured with a micrometer or caliper.
9.1.5 For OD-controlled pipe calculate the average pipe inside diameter (ID) by subtracting two times the average of all wall
thicknesses (9.1.2) from the average of all outside diameters (9.1.4). For ID-controlled pipe determine the average ID by measuring
the maximum and minimum inside diameters. Use this average ID as the basis for computing the percentage of deflection for all
specimens in that lot of pipe.
9.2 Locate the pipe section with its longitudinal axis parallel to the bearing plates and center it laterally in the testing machine.
9.2.1 If an orientation of minimum wall thickness has been found, place the first specimen so the thinnest wall is at the top and
rotate successive specimens 35 and 70°. If no minimum wall thickness was identified, use any base line.
9.3 With the deflection indicator in place, bring the upper plate into contact with the specimen with no more load than is necessary
to hold it in place. This establishes the beginning point for subsequent deflection measurements.
9.4 Compress the specimen at a constant rate of 0.50 6 0.02 in. (12.5 6 0.5 mm)/min.
NOTE 8—For larger sizes of pipe made from relatively low-modulus materials, creep may affect the results of this test because of the loading rate specified.
9.5 Record load-deflection measurements continuously or intermittently with reference to the relative movement of the bearing
plates. If measurements are made intermittently, make and record such measurements at increments of not more than 5 % of the
average inside diameter of the specimen. Refer to Annex A1.
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9.6 Observe and note the load and deflection at the first evidence of each of the following significant events when and if they
occur:
9.6.1 Liner cracking or crazing.
9.6.2 Wall cracking.
9.6.3 Wall delamination.
9.6.4 Rupture.
9.7 Record type and positi
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