ASTM_D_143_-_22.pdf

Designation:D14322Standard Test Methods forSmall Clear Specimens of Timber1This standard is issued under the fixed designation D143;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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.INTRODUCTIONThe need to classify wood species by evaluating the physical and mechanical properties of smallclear 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 comparingvariables,the need will undoubtedly continue to exist.In the preparation of these methods for testing small clear specimens,consideration was given bothto the desirability of adopting test methods that would yield results comparable to those alreadyavailable 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.ForestService,the former Forest Products Laboratories of Canada(now FPInnovations),and other similarorganizations,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 andmethods.The general adoption of these test methods will tend toward a world-wide unification ofresults,permitting an interchange and correlation of data,and establishing the basis for a cumulativebody of fundamental information on the timber species of the world.Many of the figures in thisstandard use sample data and computation sheets from testing done in the 1950s and earlier.Thesefigures remain in the standard because they are still valid depictions of the recording and plotting oftest results and also provide a historical link to the large body of test data on small clear specimensalready in existence for this long-standing test method.Descriptions of some of the strength tests refer to primary methods and secondary methods.Primarymethods provide for specimens of 2-in.by 2-in.(50 mm by 50 mm)cross section.This size ofspecimen has been extensively used for the evaluation of various mechanical and physical propertiesof different species of wood,and a large number of data based on this primary method have beenobtained and published.The 2-in.by 2-in.(50 mm by 50 mm)size has the advantage in that it embraces a number of growthrings,is less influenced by earlywood and latewood differences than smaller size specimens,and islarge enough to represent a considerable portion of the sampled material.It is advisable to use primarymethod specimens wherever possible.There are circumstances,however,when it is difficult orimpossible 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 thedesirability 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 hasbeen included.This cross section is established for compression parallel to grain and static bendingtests,while the 2-in.by 2-in.cross section is retained for impact bending,compression perpendicularto grain,hardness,shear parallel to grain,cleavage,and tension perpendicular to grain.Toughness andtension 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 necessarilydirectly comparable.Guidance on the effect of specimen size on a property being evaluated is beyondthe scope of these test methods and should be sought elsewhere.Where the application,measurement,or recording of load and deflection can be accomplished usingelectronic equipment and computerized apparatus,such devices are encouraged.It is important that alldata measurement and recording equipment,whether electronic or mechanical,be accurate andreliable to the degree specified.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 recognized 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.11.Scope1.1 These test methods cover the determination of variousstrength and related properties of wood by testing small clearspecimens.1.1.1 These test methods represent procedures for evaluat-ing the different mechanical and physical properties,control-ling factors such as specimen size,moisture content,temperature,and