1、Designation: D6570 04 (Reapproved 2010)Standard Practice forAssigning Allowable Properties for Mechanically GradedLumber1This standard is issued under the fixed designation D6570; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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.1. Scope1.1 This practice covers the methodology of grade qualifi-cation, assignment of design properties, and requiremen
3、ts forthe quality control of mechanically graded solid sawn lumber.1.2 This practice acknowledges alternative methods for theassignment of specific properties. These methods are assign-ment by test, relationship to other properties, and by proce-dures in other appropriate standards.2. Referenced Doc
4、uments2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsD143 Test Methods for Small Clear Specimens of TimberD198 Test Methods of Static Tests of Lumber in StructuralSizesD245 Practice for Establishing Structural Grades and Re-lated Allowable Properties for Visually Graded
5、LumberD1165 Nomenclature of Commercial Hardwoods and Soft-woodsD1990 Practice for Establishing Allowable Properties forVisually-Graded Dimension Lumber from In-Grade Testsof Full-Size SpecimensD2395 Test Methods for Specific Gravity of Wood andWood-Based MaterialsD2555 Practice for Establishing Clea
6、r Wood Strength Val-uesD2915 Practice for Evaluating Allowable Properties forGrades of Structural LumberD3737 Practice for Establishing Allowable Properties forStructural Glued Laminated Timber (Glulam)D4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base MaterialsD4444 T
7、est Method for Laboratory Standardization andCalibration of Hand-Held Moisture MetersD4761 Test Methods for Mechanical Properties of Lumberand Wood-Base Structural Material2.2 ANSI Standards:3ANSI/AITC A190.1 American National Standard for WoodProductsStructural Glued Laminated TimberANSI/AFand shal
8、l not be owned, operated, or controlled by any suchcompany.1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommittee D07.02 on Lumber and EngineeredWood Products.Current edition approved May 1, 2010. Published June 2010. Originallyapproved
9、 in 2000. Last previous edition approved in 2004 as D6570 041. DOI:10.1520/D6570-04R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summar
10、y page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from Canadian Standards Association (CSA), 5060 Spectrum Way,Mississauga, ON L4W 5N6, Canada, http:/www.csa.ca.5Available from National
11、Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3.2 DiscussionThe agency shall conform with theprovisions for
12、 agency accreditation under the appropriateconsensus standard.3.2.4 visual evaluation, nidentification and appraisal oflumber growth and manufacturing characteristics by visualmeans as part of the lumber segregation process.NOTE 1In the United States and Canada, criteria for agency accredi-tation ar
13、e contained in PS 20, ANSI/AITC A190.1, and CSA O141.4. Significance and Use4.1 The procedures described in this practice are intended tobe used to establish appropriate allowable unit stresses, moduliof elasticity, and specific gravity for mechanically graded solidsawn lumber. An on-going quality c
14、ontrol program to monitorcompliance with the assigned grade properties is required.5. System Requirements5.1 Mechanical Device RequirementsA mechanical de-vice used as part of the grading process shall demonstrate theability to measure the mechanical or physical wood propertyused to segregate the lu
15、mber.5.2 Visual Requirements:5.2.1 Characteristics to be limited by visual evaluation, shallbe documented as part of the qualification and quality controlprocedures. Such limitations shall be part of the grade require-ments.5.2.2 Personnel conducting visual evaluations shall bequalified by the agenc
16、y.6. Criteria for Grade Qualification6.1 General Requirements:6.1.1 A minimum of one assigned property of a grade shallbe qualified by test. The grade assignment for propertiesqualified by test is given in 7.2.6.1.1.1 If the modulus of elasticity (MOE) is the onlyproperty assigned to a grade, it sha
17、ll be evaluated by test.6.1.1.2 If both strength and MOE properties are assigned toa grade, a minimum of one strength property and one MOEproperty shall be evaluated by test. If only one strengthproperty is tested, that property shall be either the modulus ofrupture (MOR) or ultimate tensile stress
18、(UTS).6.1.2 Each grade shall be qualified at each size and for eachspecies/species group.6.1.3 Sampling, evaluation, and presentation of data shall bein accordance with Practice D2915.6.2 Qualification Samples:6.2.1 The criteria for selecting qualification samples shall bedocumented and shall be in
19、accordance with 6.1.3.6.2.2 All qualification samples shall meet the visual require-ments established for the grade.6.2.3 The minimum sample size for estimation of strengthproperties, and MOE shall be 53 specimens.6.2.4 The minimum sample size for estimation of mean ormedian property values, other t
20、han MOE, shall be 30 speci-mens.6.2.5 When the allowable shear stress parallel to grain (Fv)or the allowable compressive stress perpendicular to grain(Fc) are determined in accordance with 7.3.4 and 7.3.5,respectively, the specific gravity of a minimum of 30 qualifi-cation test specimens shall be me
21、asured and recorded.6.3 Qualification Test Methods:6.3.1 When mechanical and physical properties in Section 7are determined by tests, the appropriate ASTM standards shallbe used.6.3.2 Mechanical test methods shall be in accordance withTest Methods D143, D198,orD4761.6.3.2.1 The determination of the
22、MOE and MOR by edge-wise bending shall employ third-point in accordance with TestMethods D4761.6.3.2.2 The determination of the MOE by flat-wise bendingshall be in accordance with Test Methods D4761.6.3.2.3 The UTS of a sample shall be determined accordingto Test Methods D4761. Whenever possible, a
23、minimum gagelength of not less than 96 in. (2.44 m) shall be used. Whendetermination of the tension parallel to the grain MOE isdesired, testing shall be conducted according to the provisionsof Test Methods D198.6.3.2.4 The determination of the ultimate shear strengthparallel to grain values shall b
24、e in accordance with TestMethods D143.6.3.2.5 The determination of the compression perpendicularto grain values shall be in accordance with Test Methods D143.6.3.3 Specific gravity shall be based on weight and dimen-sions when oven dry as specified in Test Methods D2395.Measurements shall either be
25、taken on oven-dried specimens,or at some other moisture content and the values adjusted to theoven-dry condition.6.3.4 Determination of the moisture content of the lumbersample shall be in accordance with Test Methods D4442 orD4444.7. Procedures for Assignment of Allowable MechanicalProperties and S
26、pecific Gravity7.1 Allowable mechanical properties and specific gravityshall be assigned using the qualification test procedures of 7.2,the property correlation procedures of 7.3, or the procedures of7.4. These alternative procedures of 7.2-7.4 define the maxi-mum property values, which are permitte
27、d to be assigned to agrade of mechanically graded lumber.7.1.1 Selection of the procedures specified in 7.1 to estab-lish a value for any particular property assigned to a grade isthe prerogative of the grade specification author.7.1.2 The factors used in 7.2 and 7.3 apply to softwoodlumber.7.1.3 If
28、 the Fb is to be an assigned property, it shall bedetermined by the test procedures of 7.2.7.1.4 Hardwood lumber species shall be reduced by theapplicable factors in Practice D245, Table 8.7.1.4.1 Species containing interlocked grain shall have Fb,Ft, and Fc evaluated by test procedures of 7.2. Samp
29、le sizeselection shall consider the evidence of interlocked grain andits representation in the sample.7.2 Assignment of Allowable Properties by QualificationTests:7.2.1 Assignment of allowable properties by test shallfollow the procedures of this section. Test results shall beevaluated according to
30、Practice D2915.D6570 04 (2010)27.2.1.1 Qualification tests are used to either establish allow-able mechanical property values for new grades or to qualifyfor published grade categories.7.2.2 Extreme Fiber Stress in Bending (Fb)The fifthpercentile tolerance limit (75 % confidence) for the MOR of theq
31、ualification sample shall equal or exceed 2.1 times theassigned Fb value.7.2.3 Fiber Stress in Tension Parallel to Grain (Ft)Thefifth percentile tolerance limit (75 % confidence) for the UTSof the qualification sample shall equal or exceed 2.1 times theassigned Ft value.7.2.4 Fiber Stress in Compres
32、sion Parallel to Grain (Fc)The fifth percentile tolerance limit (75 % confidence) forultimate compressive strength parallel to grain (UCS)ofthequalification sample shall equal or exceed 1.9 times theassigned Fc value.7.2.5 Shear Stress Parallel to Grain (Fv)The fifth percen-tile tolerance limit (75
33、% confidence) Fv for the qualificationsample shall equal or exceed 2.1 times the assigned Fv value.7.2.6 Modulus of ElasticityThe upper 95 % confidenceinterval of the qualification sample mean MOE shall equal orexceed the assigned grade MOE.7.2.6.1 The upper bound of the 95 % confidence interval oft
34、he qualification sample mean MOE shall meet or exceed theassigned grade MOE.7.2.6.2 For grades that include a near-minimum MOE speci-fication, the sample parametric or non-parametric point esti-mate as determined in accordance with Practice D2915 shallequal or exceed the near-minimum MOE for the gra
35、de.7.2.7 Specific Gravity (SG)The upper bound of the 95 %confidence interval of the qualification sample mean specificgravity shall meet or exceed the assigned specific gravityvalue.7.2.8 Fiber Stress in Compression Perpendicular to Grain(Fc)The Fc shall be determined by test in accordancewith Test
36、Methods D143, and adjusted by the procedures ofPractice D245.7.3 Assignment of Allowable Properties Based on Relation-ships:7.3.1 The methods of 7.3 permit assignment of certainallowable properties based on recognized relationships be-tween the assigned properties. This assignment shall be inaccorda
37、nce with the following procedures.7.3.2 Fiber Stress in Tension Parallel to Grain:7.3.2.1 The maximum allowable Ft shall be assigned inaccordance with an established grade assignment model basedon the assigned Fb, which has been published by the agency.7.3.2.2 In the absence of corroborative data, a
38、 maximumFt/Fb ratio of 0.45 shall be used.7.3.3 Fiber Stress in Compression Parallel to Grain:7.3.3.1 The maximum allowable Fc shall be calculated fromthe following equation:Fc 50.7098Fb12060.7!/1.9 (1)where:Fb = the assigned Fb for the grade.7.3.4 Shear Parallel to GrainThe Fv determined by aspecif
39、ic gravity-based model (see Appendix X1) is permittedwhen the specific gravity is assigned in accordance with 7.2.7or 7.3.6.7.3.5 Fiber Stress in Compression Perpendicular to Grain(Fc)The Fc determined by a specific gravity-basedmodel (see Appendix X1) is permitted when specific gravity isassigned i
40、n accordance with 7.2.7 or 7.3.6.7.3.6 Specific GravityIt is permitted to assign specificgravity in accordance with a model that relates gradingmachine measurement to specific gravity. When such a modelis used, the agency shall develop corroborative data to supportthe appropriateness of the assigned
41、 specific gravity.7.4 Assignment of Allowable Properties by Other Standards:7.4.1 The methods of 7.4 permit assignment of certainallowable properties based on procedures in the appropriateASTM and ANSI standards.7.4.2 Shear Parallel to Grain StressThe Fv shall beassigned in accordance with the proce
42、dures of Practice D245for visually graded solid sawn lumber of the same species orspecies group.7.4.3 Fiber Stress in Compression Perpendicular toGrainThe Fc shall be assigned in accordance with theprocedures of Practice D245 for visually graded solid sawnlumber of the same species or species group.
43、7.4.4 Specific GravityThe specific gravity shall be as-signed as reported in ANSI/AF mechanically graded lumber; solid sawn lum-ber; woodAPPENDIXES(Nonmandatory Information)X1. FORMULAS FOR DETERMINING THE SHEAR STRESS PARALLEL TO GRAIN AND FIBER STRESS INCOMPRESSION PERPENDICULAR TO GRAINX1.1 Shear
44、 Stress Parallel to GrainX1.1.1 When qualified by measurement of the specificgravity (SG), the allowable stress in shear stress parallel to thegrain (Fv) shall be calculated by a relationship between SG(based on oven dry weight/oven dry volume basis) and Fv:X1.1.2 For Douglas Fir, Douglas Fir-Larch,
45、 Douglas Fir-South, Hem-Fir, Southern Pine, Spruce-Pine-Fir (South), West-ern Woods, and Western Cedars:Fv 5 266 3 SG! 1 40 (X1.1)X1.1.3 For Douglas Fir-Larch (N), Hem-Fir (N), andSpruce-Pine-Fir:Fv 5 284.8 3 SG! 1 26.6 (X1.2)where:SG = specific gravity (oven-dry weight/oven-dry volumebasis)X1.2 Com
46、pression Perpendicular to the Grain (Fc)(0.04-in. deformation limit)X1.2.1 When qualified by measurement of the SG, theallowable stress shall be calculated by a relationship betweenSG (based on oven dry weight/oven dry volume) and Fc:X1.2.1.1 For Douglas Fir, Douglas Fir-Larch, Douglas Fir-South, He
47、m-Fir, Southern Pine, Spruce-Pine-Fir (South), West-ern Woods, and Western Cedars:Fc 5 2252.4 3 SG! 480 (X1.3)X1.2.1.2 For Douglas Fir-Larch (N), Hem-Fir (N), andSpruce-Pine-Fir:Fc 5 2243.8 3 SG! 473.8 (X1.4)X1.3 Compression Perpendicular to the Grain (Fc)(0.02-in. deformation limit)X1.3.1 Refer to
48、the appropriate agency grading rules forequations to adjust the Fc from a 0.04-in. deformation limitto a 0.02-in. deformation limit.X2. EXPLANATION OF SOLID SAWN LUMBER PRODUCTS CURRENTLY PRODUCED IN THE UNITED STATES ANDCANADA BY NONDESTRUCTIVE EVALUATIONX2.1 Mechanically Graded LumberX2.1.1 Genera
49、lThe process where each piece of lumberis nondestructively evaluated by a machine to determine thevalue of the sorting parameter or grading algorithm. Mechani-cally graded lumber also is required to meet certain visualrequirements. The process assigns strength and MOE valuesbased on a model that combines information from the nonde-structive parameter and visual characteristics. One exception isE-rated lumber; strength values are not assigned to E-ratedlumber.X2.2 Machine Stress-Rated LumberX2.2.1 Lumber sorted by machine and graded based o
