ASTM D2395-17 Standard Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials.pdf

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1、Designation: D2395 17Standard Test Methods forDensity and Specific Gravity (Relative Density) of Wood andWood-Based Materials1This standard is issued under the fixed designation D2395; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision

2、, 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 methods

3、 cover the determination of thedensity and specific gravity (relative density) of wood andwood-based materials to generally desired degrees of accuracyand for specimens of different sizes, shapes, and moisturecontent conditions. The test method title is indicative of theprocedures used or the specif

4、ic area of use.SectionTest Method AVolume by Measurement 8Test Method BVolume by Water Immersion 9Test Method CFlotation Tube 10Test Method DForstner Bit 11Test Method EIncrement Core 12Test Method FChips 13Test Method GFull-Size Members 141.2 This standard does not purport to address all of thesafe

5、ty 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 limitations prior to use.1.3 This international standard was developed in accor-danc

6、e with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Stan

7、dards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsD2555 Practice for Establishing Clear Wood Strength ValuesD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Based MaterialsD5456 Specification for Evaluation of Structural CompositeLumber ProductsD7438 Practice

8、 for Field Calibration and Application ofHand-Held Moisture MetersE1547 Terminology Relating to Industrial and SpecialtyChemicals2.2 Other Standards:CAN/CSA O86 Engineering Design in Wood3ANSI/AWC National Design Specification for Wood Con-struction43. Terminology3.1 Definitions:3.1.1 For definition

9、s of terms used in this standard, refer toTerminology D9.3.2 Definitions of Terms Specific to This Standard:3.2.1 density, kg/m3, g/cm3or lb/ft3,nthe mass of aunit volume of a specimen at specified moisture content.NOTE 1The moisture content is specified for both mass and volume.For further discussi

10、on, see Appendix X3.3.2.1.1 density at moisture content Mdensity based on themass of a specimen including moisture and its volume at thesame moisture content.NOTE 2The mass and volume at 12 % moisture content are frequentlyused.3.2.1.2 density, basic or conventional, bdensity based onthe oven-dry ma

11、ss of a specimen and its green volume.3.2.1.3 density, oven-dry or in the absolute dry condition,0density based on the oven-dry mass of a specimen and itsoven-dry volume.3.2.2 green volume, nthe volume of wood specimenbefore any shrinkage occurs due to drying to moisture contentbelow the fiber satur

12、ation point (about 30 %).1These test methods are under the jurisdiction of ASTM Committee D07 onWood and are the direct responsibility of Subcommittee D07.01 on FundamentalTest Methods and Properties.Current edition approved Oct. 15, 2017. Published November 2017. Originallyapproved in 1965. Last pr

13、evious edition approved in 2014 as D2395 141. DOI:10.1520/D2395-17.2For 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 Summary page onthe ASTM we

14、bsite.3Available from CSA Group, 5060 Spectrum Way, Mississauga, ON L4W 5N6,Canada, http:/www.csa.ca.4Available fromAmerican Wood Council (AWC) 222 Catoctin Circle, SE, Suite201 Leesburg, VA 20175, www.awc.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19

15、428-2959. 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 Tech

16、nical Barriers to Trade (TBT) Committee.1NOTE 3Green volume may also be obtained by water soaking ofpartially dry wood specimens until they reach fully swollen conditionabove the fiber saturation point (for example, see 13.2.3.1). The fibersaturation point of wood averages approximately 30% moisture

17、 content,but in individual species and individual pieces of wood it can vary byseveral percentage points from that value. For further discussion, seeAppendix X3.3.2.3 moisture content, M %the amount of water con-tained in a specimen, expressed as a percentage of its oven-drymass.3.2.4 specific gravi

18、ty (relative density), S, nthe ratio of theoven-dry mass of a specimen to the mass of a volume of waterequal to the volume of the specimen at a specified moisturecontent.NOTE 4The volume may be that in the oven-dry, partially dry, orgreen (fully swollen) condition. Further in this standard, the term

19、s specificgravity and relative density are used interchangeably. For furtherdiscussion, see Appendix X3.3.2.4.1 specific gravity at moisture content M, nspecificgravity based on the oven-dry mass of a specimen and itsvolume at a specified moisture content between the oven-drycondition and the fiber

20、saturation point.NOTE 5The volume at 12 % moisture content is frequently used.3.2.4.2 specific gravity, basic (or green), Sb,nspecificgravity based on the oven-dry mass of a specimen and its greenvolume.3.2.4.3 specific gravity, oven-dry or on oven-dry basis, S0,nspecific gravity based on the oven-d

21、ry mass of a specimenand its oven-dry volume.4. Summary of Test Methods4.1 The precision of test results obtained on a representativespecimen depends upon the precision of the measurementsmade. Test Method A is used for precise measurements whenthe specimens are carefully prepared and regular in sha

22、pe. TestMethod B is used for precise measurements if the specimensare irregularly shaped and if due care is taken to preventsorption of water.Test Method C is an approximate test methodthat is permitted for use as part of a production procedure or inother situations where less precision is acceptabl

23、e. Test Meth-ods D and E are especially adapted to density or specificgravity measurements of living trees or of in-place elements,and the precision of the result is dependent upon the care usedin obtaining the specimen. Test Method F is a specificprocedure for wood chips. Test Method G provides a p

24、rocedureto estimate the overall density or specific gravity of a full-sizerectangular member that includes typical growth and manufac-turing characteristics.5. Significance and Use5.1 Density and specific gravity are cornerstone terms thathelp define many useful properties of wood and wood-basedmate

25、rials. These terms designate concepts that have distinctdefinitions though they relate to the same characteristic (massin a unit volume). Generally, in the US and Canada, density ofwood is measured in terms of specific gravity,orrelativedensity. In the wood-based composites industry and interna-tion

26、ally the term density is often preferred.5.2 The basic density and basic specific gravity of wood areused in the forestry industry for calculating the oven-dryweight of wood fiber contained in a known wood volume ofvarious wood species. Thus, it serves as an indicator of theamount of wood pulp that

27、could be produced, the workabilityof the material or its shipping weight. This information isreferenced in various resources, including Wood Handbook.5Note that specific gravity varies within a tree, between trees,and between species. Since the specific gravity of wood cellwall substance is practica

28、lly constant for all species (approxi-mately 1.53), it is apparent that individual specific gravityvalue is indicative of the amount of wood cell wall substancepresent. It affords a rapid and valuable test method for selectionof wood for specific uses. In US and Canadian building codes,the oven-dry

29、specific gravity is correlated to various strengthcharacteristics of wood products (for example, compressionperpendicular to grain, shear strength and fastener holdingcapacity).5.3 It is often desirable to know the density or specificgravity of a living tree, a structural member already in place, al

30、og cross section, a segment of a research element, or theearlywood or latewood layer. Therefore, it is possible thatspecimens will be large or small, regular or irregular in shape,and at a variety of moisture contents. These test methods giveprocedures that include all of these variables and provide

31、s forcalculation of density and specific gravity values to degrees ofprecision generally needed.5.4 In the wood-based composites industry, the productdensity or specific gravity also provides an important indicatorof potential product attributes. For wood-based materials, thesame test methods are us

32、ed; however, the measurementstypically combine the mass from the wood substance with anyresin, wax, or other solid additives present in the material.These properties are not to be confused with equivalent specificgravity of structural composite lumber used to characterize itsfastener-holding capacit

33、y determined in accordance withSpecification D5456.6. Test Specimens6.1 The test specimens shall be fully representative of thematerial from which they are taken. The specimen size shall besuch that accurate measurements of mass and volume are easyto attain. Where other standards specify the locatio

34、n and size oftest specimens, these requirements shall be carefully followed.With the exception of Test Method G, the specimens shall becarefully cut from the larger element to ensure clean-cutsurfaces. All loose fibers shall be carefully removed before thespecimen is weighed and measured. The specim

35、en shall be freefrom knots, and if pitch or other infiltrates are present, this shallbe noted in the report or they shall be extracted before takingmeasurements and weighing. The specimens for Test MethodG shall be full-size rectangular members. When Test Method Gis used with solid wood lumber, the

36、specimens shall bepermitted to include knots, wane, edge easing, pitch, or othertypical growth or manufacturing characteristics.5Forest Products Laboratory General Technical Report FPL-GTR-190, WoodHandbook: Wood as Engineering Material, Forest Products Society, 2010.D2395 1726.2 MeasurementsThe dim

37、ensions of test specimens shallbe measured to a precision of 60.3 % or less, and the massshall be determined to a precision of 60.2 % or less. Wheredrying of specimens is required, this shall be done in a forcedconvection oven that can be maintained at 103 6 2Cthroughout the drying chamber for the t

38、ime required to dry thespecimen to reach practical equilibrium. The oven shall bevented to allow the evaporated moisture to escape.NOTE 6For most specimens of wood and structural composite lumber1 in. (25 mm) in length parallel to grain, drying for 24 h in an oven havinggood air circulation and exch

39、ange will be sufficient to reach practicalequilibrium (no more than 0.2% mass change over 8 h period of drying).For other wood-based materials, the drying time should be established bytest. For further discussion, see Appendix X3.7. Moisture Content7.1 The moisture content (M) of the specimens shall

40、 bemeasured to identify the basis on which the density or specificgravity is determined. The method of determination of themoisture content depends on the size of the specimen and thepurpose of the test.7.1.1 Oven DryingThe moisture content shall be deter-mined using the oven-dry procedures of Test

41、Method D4442.With small specimens of convenient size that can be oven-dried within a reasonable timeframe, the entire piece shall beused for the moisture content determination. With largerspecimens that cannot be conveniently oven-dried, at least onerepresentative segment shall be cut from the full-

42、size specimenfor the moisture content determination. In this case, themoisture content specimens shall be as large as can bepractically dried in a reasonable timeframe and cut away fromthe member ends, wherever possible.7.1.2 Moisture MeterWhere a large solid wood specimencannot be cut to secure a m

43、oisture content segment for ovendrying, an approximate moisture content shall be permitted tobe obtained through the use of a moisture meter in accordancewith Practice D7438. The meter readings shall be corrected fortemperature and species. The use of moisture meters shall notbe permitted for materi

44、als other than solid wood.NOTE 7Since the moisture content value obtained with moisturemeter is approximate, it should be recognized that the density and specificgravity values obtained using this method are approximate. To improveaccuracy, the oven-drying method of moisture content determinationsho

45、uld be used whenever possible.8. Test Method AVolume by Measurement8.1 Applicability:8.1.1 This procedure is adaptable to any size of clear woodspecimen at any moisture content. The specimen shall beregular in shape with right-angle corners for determination ofvolume by linear measurement. If the su

46、rfaces of the specimenare smooth and sufficient measurements are taken, the volumecan be obtained with high precision. Special care shall be takenin measurement of very small or thin specimens. Volume ofirregular or rough-surfaced specimens shall be obtained byTestMethod B.8.2 Procedures:8.2.1 Volum

47、eMeasure the length, width, and thickness ofthe specimen in accordance with 6.2 in a sufficient number ofplaces to ensure a precise indication of volume.8.2.2 Initial Mass, (mM)Determine the initial mass of thespecimen at the time of test in accordance with 6.2.8.2.3 Oven-dry Mass (m0)Oven-dry mass

48、of the specimenshall be determined by drying to practical equilibrium inaccordance with 6.2 or by calculation in accordance with15.1.2 if a moisture meter is used (7.1.2).8.2.4 Moisture ContentDetermine the moisture content(M) of the specimen in accordance with 7.1.9. Test Method BVolume by Water Im

49、mersion9.1 Applicability:9.1.1 This procedure is particularly adaptable to clear woodspecimens of irregular shape or having a rough surface.NOTE 8Limitations on specimen size are based primarily on size ofimmersion tanks available. In small size specimens, less than 1 cm3involume, air bubbles adhering to the specimen surface can result inconsiderable error in volume measurement and thus in the computeddensity or specific gravity value. Freshly cut green wood will not absorbappreciable quantities of water during the brief immersi