1、Designation: C203 05a (Reapproved 2017)Standard Test Methods forBreaking Load and Flexural Properties of Block-TypeThermal Insulation1This standard is issued under the fixed designation C203; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript 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. Scope1.1 These test
3、methods cover the determination of thebreaking load and calculated flexural strength of a rectangularcross section of a preformed block-type thermal insulationtested as a simple beam. It is also applicable to cellular plastics.Two test methods are described as follows:1.1.1 Test Method IA loading sy
4、stem utilizing centerloading on a simply supported beam, supported at both ends.1.1.2 Test Method IIA loading system utilizing two sym-metric load points equally spaced from their adjacent supportpoints at each end with a distance between load points of onehalf of the support span.1.2 Either test me
5、thod is capable of being used with the fourprocedures that follow:1.2.1 Procedure ADesigned principally for materials thatbreak at comparatively small deflections.1.2.2 Procedure BDesigned particularly for those materi-als that undergo large deflections during testing.1.2.3 Procedure CDesigned for m
6、easuring at a constantstress rate, using a CRL (constant rate of loading) machine.Used for breaking load measurements only.1.2.4 Procedure DDesigned for measurements at a con-stant crosshead speed, using either a CRT (constant rate oftraverse) or CRE (constant rate of extension) machine. Usedfor bre
7、aking load measurements using a fixed crosshead speedmachine.1.3 Comparative tests are capable of being run according toeither method or procedure, provided that the method orprocedure is found satisfactory for the material being tested.1.4 These test methods are purposely general in order toaccommo
8、date the widely varying industry practices. It isimportant that the user consult the appropriate materialsspecification for any specific detailed requirements regardingthese test methods.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are provided
9、 forinformation only.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory lim
10、itations prior to use.For specific precautionary statements, see Section 111.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and R
11、ecom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C133 Test Methods for Cold Crushing Strength and Modu-lus of Rupture of RefractoriesC168 Terminology Relating to Thermal InsulationC390 Practice for Sampling a
12、nd Acceptance of ThermalInsulation LotsC870 Practice for Conditioning of Thermal Insulating Ma-terialsD76 Specification for Tensile Testing Machines for TextilesE4 Practices for Force Verification of Testing Machines3. Terminology3.1 Terminology C168 shall be considered applied to theterms used in t
13、his method.4. Summary of Test Methods4.1 A bar of rectangular cross section is tested in flexure asa beam as follows:1These test methods are under the jurisdiction of ASTM Committee C16 onThermal Insulation and are the direct responsibility of Subcommittee C16.32 onMechanical Properties.Current edit
14、ion approved Sept. 1, 2017. Published December 2017. Originallyapproved in 1945. Last previous edition approved 2012 as C203 05a (2012). DOI:10.1520/C0203-05AR17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
15、of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognize
16、d principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14.1.1 Test Method IThe bar rests on two supports and isloaded by mea
17、ns of a loading fitting or piece midway betweenthe supports (see Fig. 1).4.1.2 Test Method IIThe bar rests on two supports and isloaded at the two quarter points (by means of two loadingfittings), each an equal distance from the adjacent supportpoint. The distance between the loading fittings is one
18、 half ofthe support span (see Fig. 2).4.2 The specimen is deflected until rupture occurs, unlessthe materials specification indicates termination at a particularmaximum strain level.NOTE 1One criteria used is to limit the strain to 5 %. If failure doesnot occur at 5 % strain, the strain rate is incr
19、eased and the test repeated ona new specimen.4.3 Procedures A and B allow for testing at two differentstrain rates. Procedure C specifies a stress rate. Procedure Dspecifies a rate of extension or traverse.4.3.1 Procedure A specifies a strain rate of 0.01 in./in.(mm/mm) that is useful for testing in
20、sulations that are very stiffor break at quite low deflections.4.3.2 Procedure B specifies a strain rate of 0.1 in./in.(mm/mm) which is useful for testing insulations that arerelatively flexible or break at higher deflections.4.3.3 Procedure C specifies a stress rate of 550 psi (3.79MPa)/min except
21、as applicable in the materials specification.4.3.4 Procedure D specifies a CRE machine with a fixedcrosshead speed, or a CRT machine with a movable loadclamp, such as the Scott tester. Because the strain rate is afunction of specimen geometry, this procedure does not give aconstant strain rate for s
22、pecimens of different thicknessestested on the same loading fixture.5. Significance and Use5.1 These test methods are to be used to determine theresistance of some types of preformed block insulation whentransverse loads are normally applied to the surface. Values aremeasured at the maximum load or
23、breaking point underspecified conditions or specimen size, span between supports,and rate of load application. The equations used are based onthe assumption that the materials are uniform and presume thatthe stress-strain characteristics below the elastic limit arelinearly elastic. These assumptions
24、 are not strictly applicable tothermal insulations of certain types in which crushing occursbefore failure is obtained in transverse bending; however,depending upon the accuracy required, these procedures arecapable of providing acceptable results.5.2 Test Method I is especially useful when testing
25、only forthe modulus of rupture or the breaking load. This informationis useful for quality control inspection and qualification forspecification purposes.5.3 Test Method II is useful in determining the elasticmodulus in bending as well as the flexural strength. Flexuralproperties determined by these
26、 test methods are also useful forquality control and specification purposes.5.4 The basic differences between the two test methods is inthe location of the maximum bending moment, maximum axialfiber (flexural or tensile) stresses, and the resolved stress statein terms of shear stress and tensile/com
27、pression stress. Themaximum axial fiber stresses occur on a line under the loadingfitting in Test Method I and over the area between the loadingfittings in Test Method II. Test Method I has a high shear stresscomponent in the direction of loading, perpendicular to theaxial fiber stress. Sufficient r
28、esolved shear stress is capable ofproducing failure by a shear mode rather than a simpletension/flexural failure. There is no comparable shear compo-nent in the central region between the loading fittings in TestMethod II. Test Method II simulates a uniformly loaded beamin terms of equivalent stress
29、es at the center of the specimen.5.5 Flexural properties are capable of varing with specimenspan-to-thickness ratio, temperature, atmospheric conditions,and the difference in rate of straining specified in Procedures Aand B. In comparing results it is important that all parametersbe equivalent. Incr
30、eases in the strain rate typically result inincreased strengths and in the elastic modulus.6. Apparatus6.1 Testing MachineAproperly calibrated testing machinethat is capable of being operated at either constant load rates orconstant rates of crosshead motion over the range indicated,and in which the
31、 error in the load-measuring system shall notexceed 61 % of maximum load expected to be measured. Theload-indicating mechanism shall be essentially free of inertiallag. The accuracy and calibration of the testing machine shallbe verified in accordance with Practice E4. If stiffness ordeflection meas
32、urements are to be made, then the machineshall be equipped with a deflection-type measuring device. Thestiffness of the testing machine shall be such that the totalelastic deformation of the system does not exceed 1 % of thetotal deflection of the test specimen during test, or appropriatecorrections
33、 shall be made.6.2 Bearing EdgesThe loading fittings and supports shallhave cylindrical surfaces. In order to avoid excessiveindentation, or failure due to stress concentration directly underthe loading fitting or fittings, the diameter of these bearingedges shall be 114 614 in. (32 6 6 mm). The bea
34、ring cylindersFIG. 1 Loading System for Test Method IFIG. 2 Loading System for Test Method IIC203 05a (2017)2shall be straight and parallel to each other, and they shall beself-aligning to maintain full contact with the specimenthroughout the test. They shall have a length at least equal tothe width
35、 of the specimen.6.3 Bearing cylindrical supports are described in Test Meth-ods C133.6.4 See Fig. 1 for Test Method I; Fig. 2 for Test Method II.6.4.1 CRL machines are described in Specification D76.6.4.2 CRE and CRT machines are described in SpecificationD76.7. Safety Precautions7.1 Safety precaut
36、ions consistent with the normal usage ofany universal testing machine shall be observed. Safety glassesshould be worn when testing all brittle samples.7.2 Smoking and open flames shall be avoided when work-ing with flammable or combustible specimens.7.3 Respirators shall be worn during preparation o
37、f speci-mens that are friable or composed of compacted powder whendust levels are above permissible limits. Laboratory clothesand gloves shall be used when working with such materials ormaterial that is abrasive or a skin irritant.8. Test Specimens8.1 The number of specimens to be tested shall be gi
38、ven inthe materials specification. In the absence of such specification,test at least four samples.8.2 The specific materials specification shall be consultedfor the test specimen geometry and specific directions concern-ing selection or cutting of specimens. In the absence of suchguidance, the pref
39、erred test specimen shall be 1 in. thick by 4in. wide by 12 in. long (25 by 100 by 300 mm) tested on a 10in. (250 mm) support span. The test specimens shall be 4 in.(100 mm) unless otherwise specified, but in no case less than3 in. (75 mm) in width, and 1 in. (25 mm) thick. The testspecimens shall b
40、e long enough to accommodate a supportspan of 10 in. (250 mm) in length. The width and thickness oftest specimens shall be recorded to the nearest 0.01 in. (0.3mm).NOTE 2When comparing test results, such data must be obtainedusing a common specimen size and the same procedure.8.3 The following are c
41、ommonly used and minimum re-quirements for the test specimen geometry and test setup:Common L/d = 10 Require 20 $ L/d $ 2(Common requirement that the support span be ten times the thickness.)Common L/b = 2.5 Require L/b $ 0.8(Common requirement that support span be two and a half times thewidth.)Com
42、mon b/d = 4 Require b/d $ 1(Common requirement that the width be four times the thickness.)where:L = support span, in. (or mm),d = thickness of specimen, in. (or mm), andb = width of specimen, in. (or mm).NOTE 3Examination of the minimum test requirements shows theyare not compatible. They represent
43、 a compromise of industrial practiceswith the emphasis toward the commonly used parameters. This incom-patibility precludes a simple table of commonly used and minimumdimensions.8.4 The selection of the samples shall conform to PracticeC390. The specimens shall be cut from larger blocks orirregular
44、shapes in such a manner to preserve as many of theoriginal surfaces as acceptable. Only one sample shall be cutfrom a single block or board. Multiple specimens are capableof being cut from a sample such as a large bun of insulationmaterial. If the test specimen is cut to obtain a narrower widththan
45、as received, the cut shall be made lengthwise of the block.For anisotropic materials, flexural tests are capable of beingrun in other than the length direction, such as the crossdirection of the sample. When comparative tests are to be madeon preformed materials, all specimens shall be of the sameth
46、ickness, except as applicable in the materials specification.The bearing faces of the test specimens shall be approximatelyparallel planes. In preparing specimens from pieces of irregularshape, any means such as a band saw, or any method involvingthe use of abrasives such as high-speed abrasion whee
47、l orrubbing bed, that will produce a specimen with approximatelyplane and parallel faces (parallel within 1) without weakeningthe structure of the specimen is capable of being used. Thevalue obtained on specimens with machined surfaces will differfrom those obtained on specimens with original surfac
48、es.Consequently, the report must state if original surfaces wereretained and when only one original surface was retained,whether it was on the tension or compression side of the beam.9. Conditioning9.1 Dry and condition specimens prior to test, followingapplicable specifications for the material. In
49、 the absence ofdefinitive drying specifications, follow accepted practices forconditioning in Practice C870. Where circumstances or re-quirements preclude compliance with these conditioningprocedures, exceptions agreed upon between the manufacturerand the purchaser shall be made, and will be specifically listedin the test report.10. Procedure10.1 Test Method I, Procedure A:10.1.1 Use an untested specimen for each measurement.Measure the width and depth of the specimen to the nearest0.01 in. (0.3 mm) at the center of the support span. Eachdimension is to be measured a
