ASTM C203-99
(Test Method)Standard Test Methods for Breaking Load and Flexural Properties of Block-Type Thermal Insulation
Standard Test Methods for Breaking Load and Flexural Properties of Block-Type Thermal Insulation
SCOPE
1.1 These test methods cover the determination of the breaking load and calculated flexural strength of a rectangular cross section of a preformed block-type thermal insulation tested as a simple beam. It is also applicable to cellular plastics. Two test methods are described as follows:
1.1.1 Method I -A loading system utilizing center loading on a simply supported beam, supported at both ends.
1.1.2 Method II -A loading system utilizing two symmetric load points equally spaced from their adjacent support points at each end with a distance between load points of one half of the support span.
1.2 Either method can be used with the four procedures that follow:
1.2.1 Procedure A -Designed principally for materials that break at comparatively small deflections.
1.2.2 Procedure B -Designed particularly for those materials that undergo large deflections during testing.
1.2.3 Procedure C -Designed for measuring at a constant stress rate, using a CRL (constant rate of loading) machine. Used for breaking load measurements only.
1.2.4 Procedure D -Designed for measurements at a constant crosshead speed, using either a CRT (constant rate of traverse) or CRE (constant rate of extension) machine. Used for breaking load measurements using a fixed crosshead speed machine.
1.3 Comparative tests may be run according to either method or procedure, provided that the method or procedure is found satisfactory for the material being tested.
1.4 These test methods are purposely general in order to accommodate the widely varying industry practices. It is important that the user consult the appropriate materials specification for any specific detailed requirements regarding these test methods.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only.
1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 10.
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Designation:C203–99
Standard Test Methods for
Breaking Load and Flexural Properties of Block-Type
Thermal Insulation
This standard is issued under the fixed designation C 203; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 1.5 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are provided for
1.1 These test methods cover the determination of the
information only.
breaking load and calculated flexural strength of a rectangular
1.6 This standard does not purport to address all of the
cross section of a preformed block-type thermal insulation
safety concerns, if any, associated with its use. It is the
testedasasimplebeam.Itisalsoapplicabletocellularplastics.
responsibility of the user of this standard to establish appro-
Two test methods are described as follows:
priate safety and health practices and determine the applica-
1.1.1 Method I—A loading system utilizing center loading
bility of regulatory limitations prior to use. For specific
on a simply supported beam, supported at both ends.
precautionary statements, see Section 11.
1.1.2 Method II—Aloading system utilizing two symmetric
load points equally spaced from their adjacent support points at
2. Referenced Documents
each end with a distance between load points of one half of the
2.1 ASTM Standards:
support span.
C 133 Test Methods for Cold Crushing Strength and Modu-
1.2 Either method can be used with the four procedures that
lus of Rupture of Refractories
follow:
C 168 Terminology Relating to Thermal Insulating Materi-
1.2.1 Procedure A— Designed principally for materials that
als
break at comparatively small deflections.
C 390 Criteria for Sampling and Acceptance of Preformed
1.2.2 Procedure B— Designed particularly for those mate-
Thermal Insulation Lots
rials that undergo large deflections during testing.
C 870 Practice for Conditioning of Thermal Insulating Ma-
1.2.3 Procedure C— Designed for measuring at a constant
terials
stress rate, using a CRL (constant rate of loading) machine.
D 76 Specification for Tensile Testing Machines for Tex-
Used for breaking load measurements only.
tiles
1.2.4 Procedure D— Designed for measurements at a con-
E 4 Practice for Force Verification of Testing Machines
stant crosshead speed, using either a CRT (constant rate of
traverse) or CRE (constant rate of extension) machine. Used
3. Terminology
for breaking load measurements using a fixed crosshead speed
3.1 Terminology C 168 shall be considered as applying to
machine.
the terms used in this method.
1.3 Comparative tests may be run according to either
method or procedure, provided that the method or procedure is
4. Summary of Test Methods
found satisfactory for the material being tested.
4.1 A bar of rectangular cross section is tested in flexure as
1.4 These test methods are purposely general in order to
a beam as follows:
accommodate the widely varying industry practices. It is
4.1.1 MethodI—Thebarrestsontwosupportsandisloaded
important that the user consult the appropriate materials
by means of a loading fitting or piece midway between the
specification for any specific detailed requirements regarding
supports (see Fig. 1).
these test methods.
4.1.2 Method II—The bar rests on two supports and is
loaded at the two quarter points (by means of two loading
These test methods are under the jurisdiction of ASTM Committee C-16 on
Thermal Insulation and are the direct responsibility of Subcommittee C16.32 on
Mechanical Properties. Annual Book of ASTM Standards, Vol 15.01.
Current edition approved March 10, 1999. Published May 1999. Originally Annual Book of ASTM Standards, Vol 04.06.
published as C 203 – 45 T. Replaced C 165 – 41 T and C 203 –55 T. Last previous Annual Book of ASTM Standards, Vol 07.01.
edition C 203 – 92. Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C203
before failure is obtained in transverse bending; however,
depending upon the accuracy required, these procedures may
provide acceptable results.
5.2 Method I is especially useful when testing only for the
modulus of rupture or the breaking load. This information is
useful for quality control inspection and qualification for
specification purposes.
FIG. 1 Loading System for Method I
5.3 MethodIIisusefulindeterminingtheelasticmodulusin
bending as well as the flexural strength. Flexural properties
determined by these test methods are also useful for quality
fittings), each an equal distance from the adjacent support
control and specification purposes.
point. The distance between the loading fittings is one half of
5.4 The basic differences between the two test methods is in
the support span (see Fig. 2).
the location of the maximum bending moment, maximum axial
4.2 The specimen is deflected until rupture occurs, unless
fiber (flexural or tensile) stresses, and the resolved stress state
the materials specification indicates termination at a particular
in terms of shear stress and tensile/compression stress. The
maximum strain level.
maximum axial fiber stresses occur on a line under the loading
NOTE 1—One criteria used is to limit the strain to 5 %. If failure does
fitting in Method I and over the area between the loading
not occur at 5 % strain, the strain rate is increased and the test repeated on
fittings in Method II. Method I has a high shear stress
a new specimen.
component in the direction of loading, perpendicular to the
4.3 Procedures A and B allow for testing at two different
axial fiber stress. The resolved shear stress may be sufficient to
strain rates. Procedure C specifies a stress rate. Procedure D
produce failure by a shear mode rather than a simple tension/
specifies a rate of extension or traverse.
flexuralfailure.Thereisnocomparableshearcomponentinthe
4.3.1 Procedure A specifies a strain rate of 0.01 in./in.
central region between the loading fittings in Method II.
(mm/mm) that is useful for testing insulations that are very stiff
Method II simulates a uniformly loaded beam in terms of
or break at quite low deflections.
equivalent stresses at the center of the specimen.
4.3.2 Procedure B specifies a strain rate of 0.1 in./in.
5.5 Flexural properties may vary with specimen span-to-
(mm/mm) which is useful for testing insulations that are
thickness ratio, temperature, atmospheric conditions, and the
relatively flexible or break at higher deflections.
difference in rate of straining specified in ProceduresAand B.
4.3.3 Procedure C specifies a stress rate of 550 psi (3.79
In comparing results it is important that all parameters be
MPa)/min except as recommended in the materials specifica-
equivalent. Increases in the strain rate typically result in
tion.
increased strengths and in the elastic modulus.
4.3.4 Procedure D specifies a CRE machine with a fixed
6. Apparatus
crosshead speed, or a CRT machine with a movable load
6.1 Testing Machine— A properly calibrated testing ma-
clamp, such as the Scott tester. Because the strain rate is a
function of specimen geometry, this procedure does not give a chine that can be operated at either constant load rates or
constant strain rate for specimens of different thicknesses constant rates of crosshead motion over the range indicated,
tested on the same loading fixture. and in which the error in the load-measuring system shall not
exceed 61 % of maximum load expected to be measured. The
5. Significance and Use
load-indicating mechanism shall be essentially free of inertial
lag. The accuracy and calibration of the testing machine shall
5.1 These test methods may be used to determine the
be verified in accordance with Practice E 4. If stiffness or
resistance of some types of preformed block insulation when
deflection measurements are to be made, then the machine
transverse loads are normally applied to the surface. Values are
measured at the maximum load or breaking point under shall be equipped with a deflection-type measuring device.The
stiffness of the testing machine shall be such that the total
specified conditions or specimen size, span between supports,
and rate of load application. The equations used are based on elastic deformation of the system does not exceed 1 % of the
total deflection of the test specimen during test, or appropriate
the assumption that the materials are uniform and presume that
corrections shall be made.
the stress-strain characteristics below the elastic limit are
6.2 Bearing Edges— The loading fittings and supports shall
linearly elastic.These assumptions are not strictly applicable to
have cylindrical surfaces. In order to avoid excessive indenta-
thermal insulations of certain types in which crushing occurs
tion, or failure due to stress concentration directly under the
loading fitting or fittings, the diameter of these bearing edges
1 1
shall be 1 ⁄4 6 ⁄4 in. (32 6 6 mm). The bearing cylinders shall
be straight and parallel to each other, and they shall be
self-aligning to maintain full contact with the specimen
throughout the test. They shall have a length at least equal to
the width of the specimen.
6.3 Bearing cylindrical supports are described in Test Meth-
ods C 133.
FIG. 2 Loading System for Method II 6.4 See Fig. 1 for Method I; Fig. 2 for Method II.
C203
6.4.1 CRL machines are described in Specification D 76. anisotropicmaterials,flexuraltestsmayberuninotherthanthe
6.4.2 CRE and CRTmachines are described in Specification length direction, such as the cross direction of the sample.
D 76. When comparative tests are to be made on preformed materi-
als, all specimens shall be of the same thickness, except as
7. Safety Precautions
recommended in the materials specification. The bearing faces
7.1 Safety precautions consistent with the normal usage of
of the test specimens shall be approximately parallel planes. In
any universal testing machine should be observed. Safety
preparing specimens from pieces of irregular shape, any means
glasses should be worn when testing all brittle samples.
such as a band saw, or any method involving the use of
7.2 Smoking and open flames should be avoided when
abrasives such as high-speed abrasion wheel or rubbing bed,
working with flammable or combustible specimens.
that will produce a specimen with approximately plane and
7.3 Respirators should be worn during preparation of speci-
parallel faces (parallel within 1°) without weakening the
mens that are friable or composed of compacted powder when
structure of the specimen may be used. The value obtained on
dust levels are above permissible limits. Laboratory clothes
specimens with machined surfaces may differ from those
and gloves should be used when working with such materials
obtained on specimens with original surfaces. Consequently,
or material that may be abrasive or a skin irritant.
the report must state if original surfaces were retained and
when only one original surface was retained, whether it was on
8. Test Specimens
the tension or compression side of the beam.
8.1 Thenumberofspecimenstobetestedshouldbegivenin
thematerialsspecification.Intheabsenceofsuchspecification, 9. Conditioning
test at least four samples.
9.1 Dry and condition specimens prior to test, following
8.2 The specific materials specification should be consulted
applicable specifications for the material. In the absence of
for recommendation regarding the test specimen geometry and
definitive drying specifications, follow recommended practices
specific directions concerning selection or cutting of speci-
for conditioning in Practice C 870. Where circumstances or
mens. In the absence of such guidance, the preferred test
requirements preclude compliance with these conditioning
specimen shall be 1 in. thick by 4 in. wide by 12 in. long (25
procedures, exceptions agreed upon between the manufacturer
by 100 by 300 mm) tested on a 10 in. (250 mm) support span.
and the purchaser may be made, but they shall be specifically
The test specimens should be 4 in. (100 mm), but in no case
listed in the test report.
less than 3 in. (75 mm) in width, and 1 in. (25 mm) thick. The
test specimens shall be long enough to accommodate a support 10. Procedure
span of 10 in. (25 mm) in length. The width and thickness of
10.1 Method I, Procedure A:
test specimens shall be recorded to the nearest 0.01 in. (0.3
10.1.1 Use an untested specimen for each measurement.
mm).
Measure the width and depth of the specimen to the nearest
0.01 in. (0.3 mm) at the center of the support span. It is
NOTE 2—When comparing test results, such data must be obtained
desirable to measure each dimension at three points along the
using a common specimen size and the same procedure.
center line of the span and to use the average value of these
8.3 The following are recommended and minimum require-
measurementsinordertogetabettervalueincasethesidesare
ments for the test specimen geometry and test setup:
not truly parallel.
Recommended L/d 5 10 Require 20$ L/d$ 2
10.1.2 Determine the support span to be used and set up the
(Recommend that the support span be ten times the thickness.)
Recommended L/b 5 2.5 Require L/b$ 0.8
support span to within 1 % of the determined value. Measure
(Recommend that support span be two and a half times the width.)
this support span to the nearest 0.1 in. (3.0 mm) at three points
Recommended b/d 5 4 Require b/d$ 1
and record this measurement.
(Recommend that the width be four times the thickness.)
10.1.3 Calculate the rate of crosshead motion as follows and
where:
set the machine for the calculated rate, or as near as possible to
L 5 support span, in. (or mm),
it:
d 5 thickness of specimen, in. (or mm), and
b 5 width of specimen, in. (or mm). R 5 ZL /6d
(1)
NOTE 3—Examination of the minimum test requirements shows they
are not compatible. They represent a compromise of industrial practices
where:
with the emphasis toward the recommended parameters. This incompat-
R 5 rate of crosshead motion, in./min. (or mm/min.),
ibility precludes a simple table of recommended and minimum dimen-
L 5 support span, in. (or mm),
sions.
d 5 depth of beam, in. (or mm), and
Z 5 rate of straining of the outer fiber, in./in.·min (or
8.4 The selection of the samples shall conform to Criteria
C390. The specimens shall be cut from larger blocks or mm/mm·min). Z shall equal 0.01.
irregular shapes in such a manner to preserve as many of the In no case shall the actual crosshead
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