ASTM_D_4444_-_13.pdf

Designation:D444413Standard Test Method forLaboratory Standardization and Calibration of Hand-HeldMoisture Meters1This standard is issued under the fixed designation D4444;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method applies to the measurement of moisturecontent(MC)of solid wood products,including those contain-ing additives(that is,chemicals or adhesives)for laboratorystandardization and calibration of hand-held moisture meters1.2 This test method makes no distinction between metermeasurement technologies for standardization and calibrationrequirements.Provision is made for test specimen size toaccommodate specific meters.Appendix X1 provides an ex-planatory discussion and history corresponding to the manda-tory sections.Fundamental measurement technologies aredescribed in Appendix X2 when available.1.2.1 Meters employing differing technologies may notprovide equivalent readings under the same conditions.Whenthis test method has been applied,it is assumed that thereferenced meter is acceptable unless otherwise specified.Meters shall be calibrated with respect to MC by directmeasurement as determined by Test Methods D4442.1.3 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1990 Practice for Establishing Allowable Properties forVisually-Graded Dimension Lumber from In-Grade Testsof Full-Size SpecimensD2915 Practice for Sampling and Data-Analysis for Struc-tural Wood and Wood-Based ProductsD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Based MaterialsD4933 Guide for Moisture Conditioning of Wood andWood-Based MaterialsD5536 Practice for Sampling Forest Trees for Determinationof Clear Wood PropertiesD7438 Practice for Field Calibration and Application ofHand-Held Moisture Meters2.2 Other ASTM Sources:ASTM Standards on Precision and Bias for VariousApplications,19923.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 conductance metersConductance meters are thosethat measure predominantly ionic conductance between pointsof applied voltage,usually direct current.Direct-current con-ductance meters are commonly referred to as“resistance”meters.Most commercial conductance meters are high-inputimpedance(about 1012),wide-range(104to 1012)ohm-meters.3.1.2 capacitive-admittance metersCapacitive-admittancemeters transmit electromagnetic wave energy into the wood todetect the influence of moisture in the wood on these waves asan estimate of MC.Wave energy is most often in the radiof-requency range;hand-held meters commonly are placed di-rectly on the wood surface.4.Significance and Use4.1 Hand-held meters provide a rapid means of samplingMC of wood-based materials during and after processing tomaintain quality assurance and compliance with standards.These measurements are influenced by actual MC,a number ofother wood variables,environmental conditions,geometry ofthe measuring probe circuitry,and design of the meter.Themaximum accuracy can only be obtained by an awareness ofthe effect of each parameter on the meter output and correctionof readings as specified by this test method.4.1.1 This test method employs controlled conditions andstraight-grain,clear wood specimens to provide measurements1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.01 on Fundamental TestMethods and Properties.Current edition approved April 1,2013.Published May 2013.Originallyapproved in 1984.Last previous edition approved in 2008 as D444408.DOI:10.1520/D4444-13.2For 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 website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 that are reproducible in a laboratory.The controlled conditionsprevent moisture and temperature gradients in the test speci-men.4.1.2 In laboratory calibration,the reference direct moisturemeasurements(for example,Test Methods D4442)shall bemade only in the area of direct measurement of the meter.Thisminimizes error associated with sampling of differing areas ofmeasurement between this test method and that of the reference(Test Methods D4442).4.2 Most uses of hand-held moisture meters employ correla-tive(pred