ASTM D143-22
(Test Method)Standard Test Methods for Small Clear Specimens of Timber
Standard Test Methods for Small Clear Specimens of Timber
SIGNIFICANCE AND USE
4.1 These test methods cover tests on small clear specimens of wood that are made to provide the following:
4.1.1 Data for comparing the mechanical properties of various species,
4.1.2 Data for the establishment of correct strength functions, which in conjunction with results of tests of timbers in structural sizes (see Test Methods D198 and Test Methods D4761), afford a basis for establishing allowable stresses, and
4.1.3 Data to determine the influence on the mechanical properties of such factors as density, locality of growth, position in cross section, height of timber in the tree, change of properties with seasoning or treatment with chemicals, and change from sapwood to heartwood.
SCOPE
1.1 These test methods cover the determination of various strength and related properties of wood by testing small clear specimens.
1.1.1 These test methods represent procedures for evaluating the different mechanical and physical properties, controlling factors such as specimen size, moisture content, temperature, and rate of loading.
1.1.2 Sampling and collection of material is discussed in Practice D5536. Sample data, computation sheets, and cards have been incorporated, which were of assistance to the investigator in systematizing records.
1.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. When a weight is prescribed, the basic inch-pound unit of weight (lbf) and the basic SI unit of mass (Kg) are cited.
1.2 The procedures for the various tests appear in the following order:
Sections
Photographs of Specimens
5
Control of Moisture Content and Temperature
6
Record of Heartwood and Sapwood
7
Static Bending
8
Compression Parallel to Grain
9
Impact Bending
10
Toughness
11
Compression Perpendicular to Grain
12
Hardness
13
Shear Parallel to Grain
14
Cleavage
15
Tension Parallel to Grain
16
Tension Perpendicular to Grain
17
Nail Withdrawal
18
Specific Gravity and Shrinkage in Volume
19
Radial and Tangential Shrinkage
20
Moisture Determination
21
Permissible Variations
22
Calibration
23
1.3 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.
1.4 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
Relations
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: D143 − 22
Standard Test Methods for
Small Clear Specimens of Timber
This standard is issued under the fixed designation D143; 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.
INTRODUCTION
The need to classify wood species by evaluating the physical and mechanical properties of small
clear specimens has always existed. Because of the great variety of species, variability of the material,
continually changing conditions of supply, many factors affecting test results, and ease of comparing
variables, the need will undoubtedly continue to exist.
In the preparation of these methods for testing small clear specimens, consideration was given both
to the desirability of adopting test methods that would yield results comparable to those already
available and to the possibility of embodying such improvements as experience has shown desirable.
In view of the many thousands of tests made under a single comprehensive plan by the U.S. Forest
Service, the former Forest Products Laboratories of Canada (now FPInnovations), and other similar
organizations, these test methods naturally conform closely to the methods used by those institutions.
These test methods are the outgrowth of a study of both American and European experience and
methods. The general adoption of these test methods will tend toward a world-wide unification of
results, permitting an interchange and correlation of data, and establishing the basis for a cumulative
body of fundamental information on the timber species of the world. Many of the figures in this
standard use sample data and computation sheets from testing done in the 1950s and earlier. These
figures remain in the standard because they are still valid depictions of the recording and plotting of
test results and also provide a historical link to the large body of test data on small clear specimens
already in existence for this long-standing test method.
Descriptionsofsomeofthestrengthtestsrefertoprimarymethodsandsecondarymethods.Primary
methods provide for specimens of 2-in. by 2-in. (50 mm by 50 mm) cross section. This size of
specimen has been extensively used for the evaluation of various mechanical and physical properties
of different species of wood, and a large number of data based on this primary method have been
obtained and published.
The 2-in. by 2-in. (50 mm by 50 mm) size has the advantage in that it embraces a number of growth
rings, is less influenced by earlywood and latewood differences than smaller size specimens, and is
large enough to represent a considerable portion of the sampled material. It is advisable to use primary
method specimens wherever possible. There are circumstances, however, when it is difficult or
impossible to obtain clear specimens of 2 by 2-in. cross section having the required 30 in. (760 mm)
length for static bending tests. With the increasing incidence of smaller second growth trees, and the
desirability in certain situations to evaluate a material which is too small to provide a 2-in. by 2-in.
cross section, a secondary method which utilizes a 1-in. by 1-in. (25 mm by 25 mm) cross section has
been included. This cross section is established for compression parallel to grain and static bending
tests, while the 2-in. by 2-in. cross section is retained for impact bending, compression perpendicular
to grain, hardness, shear parallel to grain, cleavage, and tension perpendicular to grain.Toughness and
tension parallel to grain are special tests using specimens of smaller cross section.
The user is cautioned that test results between two different sizes of specimens are not necessarily
directly comparable. Guidance on the effect of specimen size on a property being evaluated is beyond
the scope of these test methods and should be sought elsewhere.
Wheretheapplication,measurement,orrecordingofloadanddeflectioncanbeaccomplishedusing
electronic equipment and computerized apparatus, such devices are encouraged. It is important that all
data measurement and recording equipment, whether electronic or mechanical, be accurate and
reliable to the degree specified.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D143 − 22
1. Scope 2. Referenced Documents
1.1 These test methods cover the determination of various 2.1 ASTM Standards:
strength and related properties of wood by testing small clear D9 Terminology Relating to Wood and Wood-Based Prod-
specimens. ucts
1.1.1 These test methods represent procedures for evaluat- D198 Test Methods of Static Tests of Lumber in Structural
ing the different mechanical and physical properties, control- Sizes
ling factors such as specimen size, moisture content, D2395 TestMethodsforDensityandSpecificGravity(Rela-
temperature, and rate of loading. tive Density) of Wood and Wood-Based Materials
1.1.2 Sampling and collection of material is discussed in D3043 Test Methods for Structural Panels in Flexure
Practice D5536. Sample data, computation sheets, and cards D4442 Test Methods for Direct Moisture Content Measure-
have been incorporated, which were of assistance to the ment of Wood and Wood-Based Materials
investigator in systematizing records. D4761 Test Methods for Mechanical Properties of Lumber
1.1.3 The values stated in inch-pound units are to be and Wood-Based Structural Materials
regarded as the standard. The values given in parentheses are D5536 Practice for Sampling ForestTrees for Determination
mathematical conversions to SI units that are provided for of Clear Wood Properties
information only and are not considered standard. When a E4 Practices for Force Calibration and Verification of Test-
weight is prescribed, the basic inch-pound unit of weight (lbf) ing Machines
and the basic SI unit of mass (Kg) are cited. E2309 Practices for Verification of Displacement Measuring
Systems and Devices Used in Material Testing Machines
1.2 The procedures for the various tests appear in the
following order:
3. Summary of Test Methods
Sections
3.1 The mechanical tests are static bending, compression
Photographs of Specimens 5
Control of Moisture Content and Temperature 6 parallel to grain, impact bending toughness, compression
Record of Heartwood and Sapwood 7
perpendicular to grain, hardness, shear parallel to grain,
Static Bending 8
cleavage, tension parallel to grain, tension-perpendicular-to-
Compression Parallel to Grain 9
Impact Bending 10
grain, and nail-withdrawal tests. These tests are permitted for
Toughness 11
both green and air-dry material as specified in these test
Compression Perpendicular to Grain 12
methods. In addition, test methods for evaluating such physical
Hardness 13
Shear Parallel to Grain 14
properties as specific gravity, shrinkage in volume, radial
Cleavage 15
shrinkage, and tangential shrinkage are presented.
Tension Parallel to Grain 16
Tension Perpendicular to Grain 17
NOTE 1—The test for shearing strength perpendicular to the grain
Nail Withdrawal 18
(sometimes termed “vertical shear”) is not included as one of the principal
Specific Gravity and Shrinkage in Volume 19
mechanical tests since in such a test the strength is limited by the shearing
Radial and Tangential Shrinkage 20
resistance parallel to the grain.
Moisture Determination 21
Permissible Variations 22
4. Significance and Use
Calibration 23
1.3 This standard does not purport to address all of the
4.1 These test methods cover tests on small clear specimens
safety concerns, if any, associated with its use. It is the
of wood that are made to provide the following:
responsibility of the user of this standard to establish appro-
4.1.1 Data for comparing the mechanical properties of
priate safety, health, and environmental practices and deter-
various species,
mine the applicability of regulatory limitations prior to use.
4.1.2 Data for the establishment of correct strength
1.4 This international standard was developed in accor-
functions, which in conjunction with results of tests of timbers
dance with internationally recognized principles on standard-
in structural sizes (see Test Methods D198 and Test Methods
ization established in the Decision on Principles for the
D4761), afford a basis for establishing allowable stresses, and
Development of International Standards, Guides and Recom-
4.1.3 Data to determine the influence on the mechanical
mendations issued by the World Trade Organization Technical
properties of such factors as density, locality of growth,
Barriers to Trade (TBT) Committee.
position in cross section, height of timber in the tree, change of
properties with seasoning or treatment with chemicals, and
change from sapwood to heartwood.
These test methods are under the jurisdiction of ASTM Committee D07 on
Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental
Test Methods and Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 15, 2022. Published June 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1922. Last previous edition approved in 2021 as D143 – 21. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D0143-22. the ASTM website.
D143 − 22
FIG. 1 Cross Sections of Bending Specimens Showing Different Rates of Growth of Longleaf Pine (2-in. by 2-in. (50 mm by 50 mm)
Specimens)
FIG. 2 Tangential Surfaces of Bending Specimens of Different Rates of Growth of Jeffrey Pine 2-in. by 2-in. by 30-in. (50 mm by 50 mm
by 760 mm) Specimens
5. Photographs of Specimens 6.2 Control of Moisture Content—Specimens for the test in
the air-dry condition shall be dried to approximately constant
5.1 Four of the static bending specimens from each species
weight before test. If any changes in moisture content occur
shall be selected for photographing, as follows: two average
during final preparation of specimens, the specimens shall be
growth, one fast growth, and one slow growth. These speci-
reconditioned to constant weight before test. Tests shall be
mens shall be photographed in cross section and on the radial
carried out in such manner that large changes in moisture
andtangentialsurfaces.Fig.1isatypicalphotographofacross
content will not occur. To prevent such changes, it is desirable
sectionof2-in.by2-in.(50mmby50mm)testspecimens,and
that the testing room and rooms for preparation of test
Fig. 2 is the tangential surface of such specimens.
specimens have some means of humidity control.
6. Control of Moisture Content and Temperature
6.3 Control of Temperature—Temperature and relative hu-
6.1 Inrecognitionofthesignificantinfluenceoftemperature midity together affect wood strength by fixing its equilibrium
and moisture content on the strength of wood, it is highly moisture content. The mechanical properties of wood are also
desirable that these factors be controlled to ensure comparable affected by temperature alone. When tested, the specimens
test results. shall be at a temperature of 68 66°F(20 6 3 °C). The
D143 − 22
temperature at the time of test shall in all instances be recorded
as a specific part of the test record.
7. Record of Heartwood and Sapwood
7.1 Proportion of Sapwood—If heartwood and sapwood
present in the specimen can be distinguished by visual
inspection, the proportion of sapwood present shall be esti-
mated as required for the purposes of the test program and
recorded for each test specimen.
8. Static Bending
8.1 Size of Specimens—The static bending tests shall be
made on 2 in. by 2 in. by 30 in. (50 mm by 50 mm by 760 mm)
primary method specimens or 1 in. by 1 in. by 16 in. (25 mm
by 25 mm by 410 mm) secondary method specimens. The
actual height and width at the center and the length shall be
measured (see 22.2).
8.2 Loading Span and Supports—Use center loading and a
span length of 28 in. (710 mm) for the primary method and 14
in. (360 mm) for the secondary method. These spans were
established in order to maintain a minimum span-to-depth ratio
of 14. Both supporting knife edges shall be provided with
FIG. 4 Example of a Bearing Block for Static Bending Tests
bearing plates and rollers of such thickness that the distance
fromthepointofsupporttothecentralplaneisnotgreaterthan
a chord length of not less than 2 in. (50 mm) shall be used for
the depth of the specimen (Fig. 3). The knife edges shall be
secondary method specimens. The bearing block shall be
adjustable laterally to permit adjustment for slight twist in the
fabricated with a material that will not appreciably deform
specimen.
under load.
NOTE 2—An example of laterally adjustable supports is provided in
8.4 Placement of Growth Rings—The specimen shall be
Figure 1 of Test Methods D3043.
placed so that the load will be applied through the bearing
8.3 Bearing Block—Arigid bearing block having a radius of
block to the tangential surface nearest the pith.
3 in. (76 mm) and a chord length of not less than 3 ⁄16 in. (97
mm) that is fixed from rotation shall be used for applying the 8.5 Speed of Testing—The load shall be applied continu-
load for primary method specimens.An example is provided in ously throughout the test at a rate of motion of the movable
Fig. 4. A similar block having a radius of 1 ⁄2 in. (38 mm) for crosshead of 0.10 in. (2.5 mm)/min, for primary method
FIG. 3 Static Bending Test Assembly Showing Test Method of Load Application, Specimen Supported on Rollers and Laterally Adjust-
able Knife Edges, and Test Method of Measuring Deflection at Neutral Axis by Means of Yoke and Displacement Measurement Device
D143 − 22
specimens,andatarateof0.05in.(1.3mm)/minforsecondary 9. Compression Parallel to Grain
method specimens (see 22.3).
9.1 Size of Specimens—The compression-parallel-to-grain
tests shall be made on 2 in. by 2 in. by 8 in. (50 mm by 50 mm
8.6 Load-Deflection Curves:
by 200 mm) primary method specimens, or 1 by 1 by 4 in. (25
8.6.1 At a minimum, the load-deflection curves shall be
by 25 by 100 mm) secondary method specimens. The actual
recorded and the test continued up to the maximum load for all
cross-sectional dimensions and the length shall be measured
static bending tests. If required for the purposes of the study, it
(s
...
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: D143 − 21 D143 − 22
Standard Test Methods for
Small Clear Specimens of Timber
This standard is issued under the fixed designation D143; 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.
INTRODUCTION
The need to classify wood species by evaluating the physical and mechanical properties of small
clear specimens has always existed. Because of the great variety of species, variability of the material,
continually changing conditions of supply, many factors affecting test results, and ease of comparing
variables, the need will undoubtedly continue to exist.
In the preparation of these methods for testing small clear specimens, consideration was given both
to the desirability of adopting test methods that would yield results comparable to those already
available and to the possibility of embodying such improvements as experience has shown desirable.
In view of the many thousands of tests made under a single comprehensive plan by the U.S. Forest
Service, the former Forest Products Laboratories of Canada (now FP Innovations), FPInnovations),
and other similar organizations, these test methods naturally conform closely to the methods used by
those institutions. These test methods are the outgrowth of a study of both American and European
experience and methods. The general adoption of these test methods will tend toward a world-wide
unification of results, permitting an interchange and correlation of data, and establishing the basis for
a cumulative body of fundamental information on the timber species of the world. Many of the figures
in this standard use sample data and computation sheets from testing done in the 1950s and earlier.
These figures remain in the standard because they are still valid depictions of the recording and
plotting of test results and also provide a historical link to the large body of test data on small clear
specimens already in existence for this long-standing test method.
Descriptions of some of the strength tests refer to primary methods and secondary methods. Primary
methods provide for specimens of 22-in. by 2-in. (50 mm by 50 mm) cross section. This size of
specimen has been extensively used for the evaluation of various mechanical and physical properties
of different species of wood, and a large number of data based on this primary method have been
obtained and published.
The 22-in. by 2-in. (50 mm by 50 mm) size has the advantage in that it embraces a number of
growth rings, is less influenced by earlywood and latewood differences than smaller size specimens,
and is large enough to represent a considerable portion of the sampled material. It is advisable to use
primary method specimens wherever possible. There are circumstances, however, when it is difficult
or impossible to obtain clear specimens of 2 by 2-in. cross section having the required 30 in. (760 mm)
length for static bending tests. With the increasing incidence of smaller second growth trees, and the
desirability in certain situations to evaluate a material which is too small to provide a 22-in. by 2-in.
cross section, a secondary method which utilizes a 11-in. by 1-in. (25 mm by 25 mm) cross section
has been included. This cross section is established for compression parallel to grain and static bending
tests, while the 22-in. by 2-in. cross section is retained for impact bending, compression perpendicular
to grain, hardness, shear parallel to grain, cleavage, and tension perpendicular to grain. Toughness and
tension parallel to grain are special tests using specimens of smaller cross section.
These test methods are under the jurisdiction of ASTM Committee D07 on Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental Test Methods
and Properties.
Current edition approved June 1, 2021May 15, 2022. Published July 2021June 2022. Originally approved in 1922. Last previous edition approved in 20142021 as
D143 – 14.D143 – 21. DOI: 10.1520/D0143-21.10.1520/D0143-22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D143 − 22
The user is cautioned that test results between two different sizes of specimens are not necessarily
directly comparable. Guidance on the effect of specimen size on a property being evaluated is beyond
the scope of these test methods and should be sought elsewhere.
Where the application, measurement, or recording of load and deflection can be accomplished using
electronic equipment and computerized apparatus, such devices are encouraged. It is important that all
data measurement and recording equipment, whether electronic or mechanical, be accurate and
reliable to the degree specified.
D143 − 22
1. Scope
1.1 These test methods cover the determination of various strength and related properties of wood by testing small clear
specimens.
1.1.1 These test methods represent procedures for evaluating the different mechanical and physical properties, controlling factors
such as specimen size, moisture content, temperature, and rate of loading.
1.1.2 Sampling and collection of material is discussed in Practice D5536. Sample data, computation sheets, and cards have been
incorporated, which were of assistance to the investigator in systematizing records.
1.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard. When a weight is prescribed, the
basic inch-pound unit of weight (lbf) and the basic SI unit of mass (Kg) are cited.
1.2 The procedures for the various tests appear in the following order:
Sections
Photographs of Specimens 5
Control of Moisture Content and Temperature 6
Record of Heartwood and Sapwood 7
Static Bending 8
Compression Parallel to Grain 9
Impact Bending 10
Toughness 11
Compression Perpendicular to Grain 12
Hardness 13
Shear Parallel to Grain 14
Cleavage 15
Tension Parallel to Grain 16
Tension Perpendicular to Grain 17
Nail Withdrawal 18
Specific Gravity and Shrinkage in Volume 19
Radial and Tangential Shrinkage 20
Moisture Determination 21
Permissible Variations 22
Calibration 23
1.3 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.
1.4 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:
D9 Terminology Relating to Wood and Wood-Based Products
D198 Test Methods of Static Tests of Lumber in Structural Sizes
D2395 Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
D3043 Test Methods for Structural Panels in Flexure
D4442 Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
D4761 Test Methods for Mechanical Properties of Lumber and Wood-Based Structural Materials
D5536 Practice for Sampling Forest Trees for Determination of Clear Wood Properties
E4 Practices for Force Calibration and Verification of Testing Machines
E2309 Practices for Verification of Displacement Measuring Systems and Devices Used in Material Testing Machines
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D143 − 22
3. Summary of Test Methods
3.1 The mechanical tests are static bending, compression parallel to grain, impact bending toughness, compression perpendicular
to grain, hardness, shear parallel to grain, cleavage, tension parallel to grain, tension-perpendicular-to-grain, and nail-withdrawal
tests. These tests are permitted for both green and air-dry material as specified in these test methods. In addition, test methods for
evaluating such physical properties as specific gravity, shrinkage in volume, radial shrinkage, and tangential shrinkage are
presented.
NOTE 1—The test for shearing strength perpendicular to the grain (sometimes termed “vertical shear”) is not included as one of the principal mechanical
tests since in such a test the strength is limited by the shearing resistance parallel to the grain.
4. Significance and Use
4.1 These test methods cover tests on small clear specimens of wood that are made to provide the following:
4.1.1 Data for comparing the mechanical properties of various species,
4.1.2 Data for the establishment of correct strength functions, which in conjunction with results of tests of timbers in structural
sizes (see Test Methods D198 and Test Methods D4761), afford a basis for establishing allowable stresses, and
4.1.3 Data to determine the influence on the mechanical properties of such factors as density, locality of growth, position in cross
section, height of timber in the tree, change of properties with seasoning or treatment with chemicals, and change from sapwood
to heartwood.
5. Photographs of Specimens
5.1 Four of the static bending specimens from each species shall be selected for photographing, as follows: two average growth,
one fast growth, and one slow growth. These specimens shall be photographed in cross section and on the radial and tangential
surfaces. Fig. 1 is a typical photograph of a cross section of 22-in. by 2-in. (50 mm by 50 mm) test specimens, and Fig. 2 is the
tangential surface of such specimens.
6. Control of Moisture Content and Temperature
6.1 In recognition of the significant influence of temperature and moisture content on the strength of wood, it is highly desirable
that these factors be controlled to ensure comparable test results.
FIG. 1 Cross Sections of Bending Specimens Showing Different Rates of Growth of Longleaf Pine (2(2-in. by 2-in. (50 mm by 50 mm)
Specimens)
D143 − 22
FIG. 2 Tangential Surfaces of Bending Specimens of Different Rates of Growth of Jeffrey Pine 22-in. by 22-in. by 30-in. (50 mm by 50
mm by 760 mm) Specimens
6.2 Control of Moisture Content—Specimens for the test in the air-dry condition shall be dried to approximately constant weight
before test. If any changes in moisture content occur during final preparation of specimens, the specimens shall be reconditioned
to constant weight before test. Tests shall be carried out in such manner that large changes in moisture content will not occur. To
prevent such changes, it is desirable that the testing room and rooms for preparation of test specimens have some means of
humidity control.
6.3 Control of Temperature—Temperature and relative humidity together affect wood strength by fixing its equilibrium moisture
content. The mechanical properties of wood are also affected by temperature alone. When tested, the specimens shall be at a
temperature of 68 6 6 °F (20 6 3 °C). The temperature at the time of test shall in all instances be recorded as a specific part of
the test record.
7. Record of Heartwood and Sapwood
7.1 Proportion of Sapwood—If heartwood and sapwood present in the specimen can be distinguished by visual inspection, the
proportion of sapwood present shall be estimated as required for the purposes of the test program and recorded for each test
specimen.
8. Static Bending
8.1 Size of Specimens—The static bending tests shall be made on 2 in. by 2 in. by 30 in. (50 mm by 50 mm by 760 mm) primary
method specimens or 1 in. by 1 in. by 16 in. (25 mm by 25 mm by 410 mm) secondary method specimens. The actual height and
width at the center and the length shall be measured (see 22.2).
8.2 Loading Span and Supports—Use center loading and a span length of 28 in. (710 mm) for the primary method and 14 in. (360
mm) for the secondary method. These spans were established in order to maintain a minimum span-to-depth ratio of 14. Both
supporting knife edges shall be provided with bearing plates and rollers of such thickness that the distance from the point of support
to the central plane is not greater than the depth of the specimen (Fig. 3). The knife edges shall be adjustable laterally to permit
adjustment for slight twist in the specimen.
NOTE 2—An example of laterally adjustable supports is provided in Figure 1 of Test Methods D3043.
8.3 Bearing Block—A rigid bearing block having a radius of 3 in. (76 mm) and a chord length of not less than 3 ⁄16 in. (97 mm)
that is fixed from rotation shall be used for applying the load for primary method specimens. An example is provided in Fig. 4.
A similar block having a radius of 1 ⁄2 in. (38 mm) for a chord length of not less than 2 in. (50 mm) shall be used for secondary
method specimens. The bearing block shall be fabricated with a material that will not appreciably deform under load.
8.4 Placement of Growth Rings—The specimen shall be placed so that the load will be applied through the bearing block to the
tangential surface nearest the pith.
D143 − 22
FIG. 3 Static Bending Test Assembly Showing Test Method of Load Application, Specimen Supported on Rollers and Laterally Adjust-
able Knife Edges, and Test Method of Measuring Deflection at Neutral Axis by Means of Yoke and Displacement Measurement Device
FIG. 4 Example of a Bearing Block for Static Bending Tests
8.5 Speed of Testing—The load shall be applied continuously throughout the test at a rate of motion of the movable crosshead of
0.10 in. (2.5 mm)/min, for primary method specimens, and at a rate of 0.05 in. (1.3 mm)/min for secondary method specimens (see
22.3).
8.6 Load-Deflection Curves:
8.6.1 At a minimum, the load-deflection curves shall be recorded and the test continued up to the maximum load for all static
bending tests. If required for the purposes of
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D143 − 22
Standard Test Methods for
Small Clear Specimens of Timber
This standard is issued under the fixed designation D143; 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.
INTRODUCTION
The need to classify wood species by evaluating the physical and mechanical properties of small
clear specimens has always existed. Because of the great variety of species, variability of the material,
continually changing conditions of supply, many factors affecting test results, and ease of comparing
variables, the need will undoubtedly continue to exist.
In the preparation of these methods for testing small clear specimens, consideration was given both
to the desirability of adopting test methods that would yield results comparable to those already
available and to the possibility of embodying such improvements as experience has shown desirable.
In view of the many thousands of tests made under a single comprehensive plan by the U.S. Forest
Service, the former Forest Products Laboratories of Canada (now FPInnovations), and other similar
organizations, these test methods naturally conform closely to the methods used by those institutions.
These test methods are the outgrowth of a study of both American and European experience and
methods. The general adoption of these test methods will tend toward a world-wide unification of
results, permitting an interchange and correlation of data, and establishing the basis for a cumulative
body of fundamental information on the timber species of the world. Many of the figures in this
standard use sample data and computation sheets from testing done in the 1950s and earlier. These
figures remain in the standard because they are still valid depictions of the recording and plotting of
test results and also provide a historical link to the large body of test data on small clear specimens
already in existence for this long-standing test method.
Descriptions of some of the strength tests refer to primary methods and secondary methods. Primary
methods provide for specimens of 2-in. by 2-in. (50 mm by 50 mm) cross section. This size of
specimen has been extensively used for the evaluation of various mechanical and physical properties
of different species of wood, and a large number of data based on this primary method have been
obtained and published.
The 2-in. by 2-in. (50 mm by 50 mm) size has the advantage in that it embraces a number of growth
rings, is less influenced by earlywood and latewood differences than smaller size specimens, and is
large enough to represent a considerable portion of the sampled material. It is advisable to use primary
method specimens wherever possible. There are circumstances, however, when it is difficult or
impossible to obtain clear specimens of 2 by 2-in. cross section having the required 30 in. (760 mm)
length for static bending tests. With the increasing incidence of smaller second growth trees, and the
desirability in certain situations to evaluate a material which is too small to provide a 2-in. by 2-in.
cross section, a secondary method which utilizes a 1-in. by 1-in. (25 mm by 25 mm) cross section has
been included. This cross section is established for compression parallel to grain and static bending
tests, while the 2-in. by 2-in. cross section is retained for impact bending, compression perpendicular
to grain, hardness, shear parallel to grain, cleavage, and tension perpendicular to grain. Toughness and
tension parallel to grain are special tests using specimens of smaller cross section.
The user is cautioned that test results between two different sizes of specimens are not necessarily
directly comparable. Guidance on the effect of specimen size on a property being evaluated is beyond
the scope of these test methods and should be sought elsewhere.
Where the application, measurement, or recording of load and deflection can be accomplished using
electronic equipment and computerized apparatus, such devices are encouraged. It is important that all
data measurement and recording equipment, whether electronic or mechanical, be accurate and
reliable to the degree specified.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D143 − 22
1. Scope 2. Referenced Documents
1.1 These test methods cover the determination of various 2.1 ASTM Standards:
strength and related properties of wood by testing small clear D9 Terminology Relating to Wood and Wood-Based Prod-
specimens. ucts
1.1.1 These test methods represent procedures for evaluat- D198 Test Methods of Static Tests of Lumber in Structural
ing the different mechanical and physical properties, control- Sizes
ling factors such as specimen size, moisture content, D2395 Test Methods for Density and Specific Gravity (Rela-
temperature, and rate of loading. tive Density) of Wood and Wood-Based Materials
1.1.2 Sampling and collection of material is discussed in D3043 Test Methods for Structural Panels in Flexure
Practice D5536. Sample data, computation sheets, and cards D4442 Test Methods for Direct Moisture Content Measure-
have been incorporated, which were of assistance to the ment of Wood and Wood-Based Materials
investigator in systematizing records. D4761 Test Methods for Mechanical Properties of Lumber
1.1.3 The values stated in inch-pound units are to be and Wood-Based Structural Materials
regarded as the standard. The values given in parentheses are D5536 Practice for Sampling Forest Trees for Determination
mathematical conversions to SI units that are provided for of Clear Wood Properties
information only and are not considered standard. When a E4 Practices for Force Calibration and Verification of Test-
weight is prescribed, the basic inch-pound unit of weight (lbf) ing Machines
and the basic SI unit of mass (Kg) are cited. E2309 Practices for Verification of Displacement Measuring
Systems and Devices Used in Material Testing Machines
1.2 The procedures for the various tests appear in the
following order:
3. Summary of Test Methods
Sections
3.1 The mechanical tests are static bending, compression
Photographs of Specimens 5
Control of Moisture Content and Temperature 6
parallel to grain, impact bending toughness, compression
Record of Heartwood and Sapwood 7
perpendicular to grain, hardness, shear parallel to grain,
Static Bending 8
cleavage, tension parallel to grain, tension-perpendicular-to-
Compression Parallel to Grain 9
Impact Bending 10 grain, and nail-withdrawal tests. These tests are permitted for
Toughness 11
both green and air-dry material as specified in these test
Compression Perpendicular to Grain 12
methods. In addition, test methods for evaluating such physical
Hardness 13
Shear Parallel to Grain 14
properties as specific gravity, shrinkage in volume, radial
Cleavage 15
shrinkage, and tangential shrinkage are presented.
Tension Parallel to Grain 16
Tension Perpendicular to Grain 17
NOTE 1—The test for shearing strength perpendicular to the grain
Nail Withdrawal 18
(sometimes termed “vertical shear”) is not included as one of the principal
Specific Gravity and Shrinkage in Volume 19
mechanical tests since in such a test the strength is limited by the shearing
Radial and Tangential Shrinkage 20
resistance parallel to the grain.
Moisture Determination 21
Permissible Variations 22
4. Significance and Use
Calibration 23
1.3 This standard does not purport to address all of the
4.1 These test methods cover tests on small clear specimens
safety concerns, if any, associated with its use. It is the
of wood that are made to provide the following:
responsibility of the user of this standard to establish appro-
4.1.1 Data for comparing the mechanical properties of
priate safety, health, and environmental practices and deter-
various species,
mine the applicability of regulatory limitations prior to use.
4.1.2 Data for the establishment of correct strength
1.4 This international standard was developed in accor-
functions, which in conjunction with results of tests of timbers
dance with internationally recognized principles on standard-
in structural sizes (see Test Methods D198 and Test Methods
ization established in the Decision on Principles for the
D4761), afford a basis for establishing allowable stresses, and
Development of International Standards, Guides and Recom-
4.1.3 Data to determine the influence on the mechanical
mendations issued by the World Trade Organization Technical
properties of such factors as density, locality of growth,
Barriers to Trade (TBT) Committee.
position in cross section, height of timber in the tree, change of
properties with seasoning or treatment with chemicals, and
change from sapwood to heartwood.
These test methods are under the jurisdiction of ASTM Committee D07 on
Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental
Test Methods and Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 15, 2022. Published June 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1922. Last previous edition approved in 2021 as D143 – 21. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D0143-22. the ASTM website.
D143 − 22
FIG. 1 Cross Sections of Bending Specimens Showing Different Rates of Growth of Longleaf Pine (2-in. by 2-in. (50 mm by 50 mm)
Specimens)
FIG. 2 Tangential Surfaces of Bending Specimens of Different Rates of Growth of Jeffrey Pine 2-in. by 2-in. by 30-in. (50 mm by 50 mm
by 760 mm) Specimens
5. Photographs of Specimens 6.2 Control of Moisture Content—Specimens for the test in
the air-dry condition shall be dried to approximately constant
5.1 Four of the static bending specimens from each species
weight before test. If any changes in moisture content occur
shall be selected for photographing, as follows: two average
during final preparation of specimens, the specimens shall be
growth, one fast growth, and one slow growth. These speci-
reconditioned to constant weight before test. Tests shall be
mens shall be photographed in cross section and on the radial
carried out in such manner that large changes in moisture
and tangential surfaces. Fig. 1 is a typical photograph of a cross
content will not occur. To prevent such changes, it is desirable
section of 2-in. by 2-in. (50 mm by 50 mm) test specimens, and
that the testing room and rooms for preparation of test
Fig. 2 is the tangential surface of such specimens.
specimens have some means of humidity control.
6. Control of Moisture Content and Temperature
6.3 Control of Temperature—Temperature and relative hu-
6.1 In recognition of the significant influence of temperature midity together affect wood strength by fixing its equilibrium
and moisture content on the strength of wood, it is highly moisture content. The mechanical properties of wood are also
desirable that these factors be controlled to ensure comparable affected by temperature alone. When tested, the specimens
test results. shall be at a temperature of 68 6 6 °F (20 6 3 °C). The
D143 − 22
temperature at the time of test shall in all instances be recorded
as a specific part of the test record.
7. Record of Heartwood and Sapwood
7.1 Proportion of Sapwood—If heartwood and sapwood
present in the specimen can be distinguished by visual
inspection, the proportion of sapwood present shall be esti-
mated as required for the purposes of the test program and
recorded for each test specimen.
8. Static Bending
8.1 Size of Specimens—The static bending tests shall be
made on 2 in. by 2 in. by 30 in. (50 mm by 50 mm by 760 mm)
primary method specimens or 1 in. by 1 in. by 16 in. (25 mm
by 25 mm by 410 mm) secondary method specimens. The
actual height and width at the center and the length shall be
measured (see 22.2).
8.2 Loading Span and Supports—Use center loading and a
span length of 28 in. (710 mm) for the primary method and 14
in. (360 mm) for the secondary method. These spans were
established in order to maintain a minimum span-to-depth ratio
of 14. Both supporting knife edges shall be provided with
FIG. 4 Example of a Bearing Block for Static Bending Tests
bearing plates and rollers of such thickness that the distance
from the point of support to the central plane is not greater than
a chord length of not less than 2 in. (50 mm) shall be used for
the depth of the specimen (Fig. 3). The knife edges shall be
secondary method specimens. The bearing block shall be
adjustable laterally to permit adjustment for slight twist in the
fabricated with a material that will not appreciably deform
specimen.
under load.
NOTE 2—An example of laterally adjustable supports is provided in
8.4 Placement of Growth Rings—The specimen shall be
Figure 1 of Test Methods D3043.
placed so that the load will be applied through the bearing
8.3 Bearing Block—A rigid bearing block having a radius of
block to the tangential surface nearest the pith.
3 in. (76 mm) and a chord length of not less than 3 ⁄16 in. (97
mm) that is fixed from rotation shall be used for applying the 8.5 Speed of Testing—The load shall be applied continu-
load for primary method specimens. An example is provided in ously throughout the test at a rate of motion of the movable
Fig. 4. A similar block having a radius of 1 ⁄2 in. (38 mm) for crosshead of 0.10 in. (2.5 mm)/min, for primary method
FIG. 3 Static Bending Test Assembly Showing Test Method of Load Application, Specimen Supported on Rollers and Laterally Adjust-
able Knife Edges, and Test Method of Measuring Deflection at Neutral Axis by Means of Yoke and Displacement Measurement Device
D143 − 22
specimens, and at a rate of 0.05 in. (1.3 mm)/min for secondary 9. Compression Parallel to Grain
method specimens (see 22.3).
9.1 Size of Specimens—The compression-parallel-to-grain
tests shall be made on 2 in. by 2 in. by 8 in. (50 mm by 50 mm
8.6 Load-Deflection Curves:
by 200 mm) primary method specimens, or 1 by 1 by 4 in. (25
8.6.1 At a minimum, the load-deflection curves shall be
by 25 by 100 mm) secondary method specimens. The actual
recorded and the test continued up to the maximum load for all
cross-sectional dimensions and the length shall be measured
static bending tests. If required for the purposes of the study, it
(see 22.2).
shall be permitted to continu
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