ASTM D6570-04(2010)
(Practice)Standard Practice for Assigning Allowable Properties for Mechanically Graded Lumber
Standard Practice for Assigning Allowable Properties for Mechanically Graded Lumber
SIGNIFICANCE AND USE
The procedures described in this practice are intended to be used to establish appropriate allowable unit stresses, moduli of elasticity, and specific gravity for mechanically graded solid sawn lumber. An on-going quality control program to monitor compliance with the assigned grade properties is required.
SCOPE
1.1 This practice covers the methodology of grade qualification, assignment of design properties, and requirements for the quality control of mechanically graded solid sawn lumber.
1.2 This practice acknowledges alternative methods for the assignment of specific properties. These methods are assignment by test, relationship to other properties, and by procedures in other appropriate standards.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D6570 − 04 (Reapproved 2010)
Standard Practice for
Assigning Allowable Properties for Mechanically Graded
Lumber
This standard is issued under the fixed designation D6570; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope ment of Wood and Wood-Based Materials
D4444Test Method for Laboratory Standardization and
1.1 This practice covers the methodology of grade
Calibration of Hand-Held Moisture Meters
qualification, assignment of design properties, and require-
D4761Test Methods for Mechanical Properties of Lumber
ments for the quality control of mechanically graded solid
and Wood-Base Structural Material
sawn lumber.
2.2 ANSI Standards:
1.2 This practice acknowledges alternative methods for the
ANSI/AITCA190.1American National Standard for Wood
assignment of specific properties. These methods are assign-
Products—Structural Glued Laminated Timber
ment by test, relationship to other properties, and by proce-
ANSI/AF&PANDSNationalDesignSpecificationforWood
dures in other appropriate standards.
Construction
2.3 Canadian Standards Association Standard:
2. Referenced Documents
CSAO141Softwood Lumber
2.1 ASTM Standards:
2.4 National Institute of Standards and Technology Stan-
D9Terminology Relating to Wood and Wood-Based Prod-
dard:
ucts
PS20Voluntary Product Standard, American Softwood
D143Test Methods for Small Clear Specimens of Timber
Lumber Standard
D198Test Methods of Static Tests of Lumber in Structural
Sizes
3. Terminology
D245Practice for Establishing Structural Grades and Re-
lated Allowable Properties for Visually Graded Lumber
3.1 Definitions—For definitions of terms related to wood,
D1165Nomenclature of Commercial Hardwoods and Soft-
refer to Terminology D9.
woods
3.2 Definitions of Terms Specific to This Standard:
D1990Practice for Establishing Allowable Properties for
3.2.1 mechanical evaluation, n—identificationandappraisal
Visually-Graded Dimension Lumber from In-Grade Tests
of one or more physical or mechanical lumber characteristics
of Full-Size Specimens
as part of the lumber segregation process.
D2395TestMethodsforDensityandSpecificGravity(Rela-
3.2.2 mechanically graded lumber, n—solid sawn lumber
tive Density) of Wood and Wood-Based Materials
graded by mechanical evaluation. Visual evaluation also may
D2555PracticeforEstablishingClearWoodStrengthValues
berequired.Thematerialhasassigneddesignpropertiesandis
D2915Practice for Sampling and Data-Analysis for Struc-
manufactured for use as structural members.
tural Wood and Wood-Based Products
3.2.3 qualified agency, n—an organization, hereafter re-
D3737Practice for Establishing Allowable Properties for
Structural Glued Laminated Timber (Glulam) ferred to as the agency, that has trained personnel and proce-
D4442Test Methods for Direct Moisture Content Measure- durestoensurethesystemevaluationsandgradescomplywith
all applicable requirements of this practice.
3.2.3.1 Discussion—The agency shall have no financial
This practice is under the jurisdiction ofASTM Committee D07 on Wood and
interest in, nor shall be financially dependent upon, any single
is the direct responsibility of Subcommittee D07.02 on Lumber and Engineered
Wood Products.
Current edition approved May 1, 2010. Published June 2010. Originally
ε1
approved in 2000. Last previous edition approved in 2004 as D6570–04 . DOI: Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/D6570-04R10. 4th Floor, New York, NY 10036, http://www.ansi.org.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Canadian Standards Association (CSA), 5060 Spectrum Way,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Mississauga, ON L4W 5N6, Canada, http://www.csa.ca.
Standards volume information, refer to the standard’s Document Summary page on Available from National Institute of Standards and Technology (NIST), 100
the ASTM website. Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6570 − 04 (2010)
company manufacturing the product being inspected or tested; 6.2.5 When the allowable shear stress parallel to grain (Fv)
and shall not be owned, operated, or controlled by any such or the allowable compressive stress perpendicular to grain
company. (Fc') are determined in accordance with 7.3.4 and 7.3.5,
3.2.3.2 Discussion—The agency shall conform with the respectively, the specific gravity of a minimum of 30 qualifi-
provisions for agency accreditation under the appropriate cation test specimens shall be measured and recorded.
consensus standard.
6.3 Qualification Test Methods:
3.2.4 visual evaluation, n—identification and appraisal of
6.3.1 WhenmechanicalandphysicalpropertiesinSection7
lumber growth and manufacturing characteristics by visual
are determined by tests, the appropriateASTM standards shall
means as part of the lumber segregation process.
be used.
6.3.2 Mechanical test methods shall be in accordance with
NOTE 1—In the United States and Canada, criteria for agency accredi-
tation are contained in PS20, ANSI/AITCA190.1, and CSAO141. Test Methods D143, D198,or D4761.
6.3.2.1 The determination of the MOE and MOR by edge-
4. Significance and Use
wise bending shall employ third-point in accordance with Test
4.1 Theproceduresdescribedinthispracticeareintendedto
Methods D4761.
beusedtoestablishappropriateallowableunitstresses,moduli
6.3.2.2 The determination of the MOE by flat-wise bending
ofelasticity,andspecificgravityformechanicallygradedsolid
shall be in accordance with Test Methods D4761.
sawn lumber.An on-going quality control program to monitor
6.3.2.3 The UTS of a sample shall be determined according
compliance with the assigned grade properties is required.
to Test Methods D4761. Whenever possible, a minimum gage
length of not less than 96 in. (2.44 m) shall be used. When
5. System Requirements
determination of the tension parallel to the grain MOE is
5.1 Mechanical Device Requirements —A mechanical de-
desired, testing shall be conducted according to the provisions
vice used as part of the grading process shall demonstrate the
of Test Methods D198.
ability to measure the mechanical or physical wood property
6.3.2.4 The determination of the ultimate shear strength
used to segregate the lumber.
parallel to grain values shall be in accordance with Test
5.2 Visual Requirements:
Methods D143.
5.2.1 Characteristicstobelimitedbyvisualevaluation,shall
6.3.2.5 Thedeterminationofthecompressionperpendicular
be documented as part of the qualification and quality control
tograinvaluesshallbeinaccordancewithTestMethodsD143.
procedures. Such limitations shall be part of the grade require-
6.3.3 Specific gravity shall be based on weight and dimen-
ments.
sions when oven dry as specified in Test Methods D2395.
5.2.2 Personnel conducting visual evaluations shall be
Measurements shall either be taken on oven-dried specimens,
qualified by the agency.
oratsomeothermoisturecontentandthevaluesadjustedtothe
oven-dry condition.
6. Criteria for Grade Qualification
6.3.4 Determination of the moisture content of the lumber
6.1 General Requirements:
sample shall be in accordance with Test Methods D4442 or
6.1.1 Aminimum of one assigned property of a grade shall
D4444.
be qualified by test. The grade assignment for properties
qualified by test is given in 7.2.
7. Procedures for Assignment of Allowable Mechanical
6.1.1.1 If the modulus of elasticity (MOE) is the only
Properties and Specific Gravity
property assigned to a grade, it shall be evaluated by test.
6.1.1.2 If both strength and MOE properties are assigned to 7.1 Allowable mechanical properties and specific gravity
a grade, a minimum of one strength property and one MOE shall be assigned using the qualification test procedures of 7.2,
property shall be evaluated by test. If only one strength thepropertycorrelationproceduresof7.3,ortheproceduresof
property is tested, that property shall be either the modulus of 7.4. These alternative procedures of 7.2 – 7.4 define the
maximum property values, which are permitted to be assigned
rupture (MOR) or ultimate tensile stress (UTS).
6.1.2 Each grade shallbequalifiedateachsizeand for each to a grade of mechanically graded lumber.
species/species group. 7.1.1 Selection of the procedures specified in 7.1 to estab-
6.1.3 Sampling,evaluation,andpresentationofdatashallbe
lish a value for any particular property assigned to a grade is
in accordance with Practice D2915.
the prerogative of the grade specification author.
7.1.2 The factors used in 7.2 and 7.3 apply to softwood
6.2 Qualification Samples:
lumber.
6.2.1 Thecriteriaforselectingqualificationsamplesshallbe
7.1.3 If the Fb is to be an assigned property, it shall be
documented and shall be in accordance with 6.1.3.
determined by the test procedures of 7.2.
6.2.2 Allqualificationsamplesshallmeetthevisualrequire-
7.1.4 Hardwood lumber species shall be reduced by the
ments established for the grade.
applicable factors in Practice D245, Table8.
6.2.3 The minimum sample size for estimation of strength
properties, and MOE shall be 53 specimens. 7.1.4.1 Species containing interlocked grain shall have Fb,
6.2.4 The minimum sample size for estimation of mean or Ft, and Fc evaluated by test procedures of 7.2. Sample size
median property values, other than MOE, shall be 30 speci- selection shall consider the evidence of interlocked grain and
mens. its representation in the sample.
D6570 − 04 (2010)
7.2 Assignment of Allowable Properties by Qualification where:
Tests:
Fb = the assigned Fb for the grade.
7.2.1 Assignment of allowable properties by test shall
7.3.4 Shear Parallel to Grain—The Fv determined by a
follow the procedures of this section. Test results shall be
specific gravity-based model (see Appendix X1) is permitted
evaluated according to Practice D2915.
when the specific gravity is assigned in accordance with 7.2.7
7.2.1.1 Qualificationtestsareusedtoeitherestablishallow-
or 7.3.6.
able mechanical property values for new grades or to qualify
7.3.5 Fiber Stress in Compression Perpendicular to Grain
for published grade categories.
(Fc')—The Fc' determined by a specific gravity-based
7.2.2 Extreme Fiber Stress in Bending (Fb)—The fifth
model(seeAppendixX1)ispermittedwhenspecificgravityis
percentiletolerancelimit(75%confidence)fortheMORofthe
assigned in accordance with 7.2.7 or 7.3.6.
qualification sample shall equal or exceed 2.1 times the
7.3.6 Specific Gravity—It is permitted to assign specific
assigned Fb value.
gravity in accordance with a model that relates grading
7.2.3 Fiber Stress in Tension Parallel to Grain (Ft)—The
machine measurement to specific gravity. When such a model
fifth percentile tolerance limit (75% confidence) for the UTS
is used, the agency shall develop corroborative data to support
of the qualification sample shall equal or exceed 2.1 times the
the appropriateness of the assigned specific gravity.
assigned Ft value.
7.4 Assignment of Allowable Properties by Other Stan-
7.2.4 Fiber Stress in Compression Parallel to Grain (Fc)—
dards:
The fifth percentile tolerance limit (75% confidence) for
7.4.1 The methods of 7.4 permit assignment of certain
ultimate compressive strength parallel to grain (UCS)ofthe
allowable properties based on procedures in the appropriate
qualification sample shall equal or exceed 1.9 times the
ASTM and ANSI standards.
assigned Fc value.
7.4.2 Shear Parallel to Grain Stress—The Fv shall be
7.2.5 Shear Stress Parallel to Grain (Fv)—Thefifthpercen-
assigned in accordance with the procedures of Practice D245
tile tolerance limit (75% confidence) Fv for the qualification
for visually graded solid sawn lumber of the same species or
sample shall equal or exceed 2.1 times the assigned Fv value.
species group.
7.2.6 Modulus of Elasticity—The upper 95% confidence
7.4.3 FiberStressinCompressionPerpendiculartoGrain—
interval of the qualification sample mean MOE shall equal or
The Fc' shall be assigned in accordance with the procedures
exceed the assigned grade MOE.
of Practice D245 for visually graded solid sawn lumber of the
7.2.6.1 The upper bound of the 95% confidence interval of
same species or species group.
the qualification sample mean MOE shall meet or exceed the
7.4.4 Specific Gravity—The specific gravity shall be as-
assigned grade MOE.
signed as reported in ANSI/AF&PANDS for visually graded
7.2.6.2 For grades that include a near-minimum MOE
solid sawn lumber of the same species or species group.
specification, the sample parametric or non-parametric point
estimate as determined in accordance with Practice D2915
8. Minimum Allowable Property Increment
shall equal or exceed the near-minimum MOE for the grade.
7.2.7 Specific Gravity (SG)—The upper bound of the 95%
8.1 Allowable properties shall be rounded in accordance
confidence interval of the qualification sample mean specific with Table 1.
gravity shall meet or exceed the assigned specific gravity
9. Quality Control
value.
7.2.8 Fiber Stress in Compression Perpendicular to Grain
9.1 A quality control program shall be developed for each
(Fc')—The Fc' shall be determined by test in accordance
mechanical grading system. The quality control program shall
with Test Methods D143, and adjusted by the procedures of
delineatetherespectiveresponsibilitiesoftheproducerandthe
Practice D245.
agency.
7.3 Assignment of Allowable Properties Based on Relation-
9.2 The quality control program shall include monitoring
ships:
and control of both the mechanical and visual portions of the
7.3.1 The methods of 7.3 permit assignment of certain
system.
allowable properties based on recognized relationships be-
9.2.1 The visual evaluation of the grade shall be conducted
tween the assigned properties. This assignment shall be in
in accordance with the applicable agency requirements.
accordance 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 in
TABLE 1 Rounding Rules for Allowable Property Values
accordance with an established grade assignment model based
MOE 100 000 psi
on the assigned Fb, which has been published by the agency.
Fb 50 psi at 1000 psi
7.3.2.2 In the absence of corroborative data, a maximum
and above
25 psi below 1000 psi
Ft/Fb ratio of 0.45 shall be used.
Ft 25 psi
7.3.3 Fiber Stress in Compression Parallel to Grain:
Fc 25 psi
7.3.3.1 ThemaximumallowableFcshallbecalculatedfrom
Fc' 5 psi
Fv 5 psi
...
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