ASTM_D_7433_-_13.pdf

Designation:D743313Standard Test Method forMeasuring Surface Water Absorption of Overlaid Wood-Based Panels1This standard is issued under the fixed designation D7433;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.1.Scope1.1 This test method covers the determination of the quan-tity of water absorbed in a specified time through the surface ofan overlaid wood-based panel.The test method measures therate of water gain within a controlled surface area of theoverlaid panel surface when exposed to standing water.Themethod was adapted from the principles of Test MethodD5795.1.2 This test method is applicable to various overlaidwood-based panels including,but not limited to,plywood(such as MDO grades and HDO grades referenced in PS 109),orientedstrandboard,mediumdensityfiberboard,particleboard,and hardboard.1.3 This test method does not address sampling procedures,number of replications nor performance criteria since thosedetails vary depending upon the purpose of the testing and thetype of product.The method is specific to the panel surface anddoes not evaluate water absorption or edge swell that mayoccur along panel edges.The method does not consider thevariables related to in-service moisture conditions and there-fore does not claim to directly relate to water absorption thatmay occur in actual panel use situations.1.4 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.1.5 This test method does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this test method to establishappropriate safety and health practices and determine theapplicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D5795 Test Method for Determination of Liquid WaterAbsorption of Coated Hardboard and Other CompositeWood Products Via“Cobb Ring”ApparatusD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base Materials2.2 Other Standards:3PS 109 U.S.Voluntary Product Standard,Structural Ply-wood3.Significance and Use3.1 Water absorptiveness through the surface of an overlaidpanel is a function of various characteristics of the overlay andsubstrate,including overlay resin content,thickness of theoverlay,porosity,and permeability.3.2 This test method is useful in comparing the waterabsorption characteristics of different overlaid panel products.The results from this test method are influenced by both theperformance of the overlay system and the panel substrate.Therefore,the results are appropriate for comparison of therelative performance of an overlay system when tested oversimilar or matched panel substrates.NOTE1Panel attributes that may influence water absorption include,but are not limited to,panel type,wood species,face veneer thickness andgrade,preoverlay surface treatment such as sanding,particle geometry andcompaction ratio.1This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.03 on Panel Products.Current edition approved Aug.1,2013.Published September 2013.Originallyapproved in 2008.Last previous edition approved in 2008 as D743308.DOI:10.1520/D7433-13.2For 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.3Available from National Institute of Standards and Technology(NIST),100Bureau Dr.,Stop 1070,Gaithersburg,MD 20899-1070,http:/www.nist.gov/standardsCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Test Apparatus and Materials4.1 Rings,formed by cut sections of metal or plastic pipewith inside diameter of approximately 108 mm(4.25 in.)whichcan be sealed to the overlaid panel with silicone or elastomericsealant.4.2 Scale,to measure the depth of water column within 0.5mm(0.020 in.)accuracy.The cross section of the scale shall beas small as practical to minimize interference with the waterdepth.NOTE2A steel pocket scale with etched graduations at 0.01 in.issuitable.4.3 Mixture of equal parts beeswax and rosin,to create acoating for the exterior of the specimen in order to preventweight change due to absorption or desorption of moisturefrom the panel specimen in areas other than the test area.Othersealants that provide equivalent water repellency are permitted.4.4 Hotplate and suitable pan for melting the mixture ofbeeswax and rosin in which the specimens are dipped.4.5 Balance,with an accuracy of 0.01 g.4.6 Water,distilled or deionized.4.7 Sealant,100%silicone or elastomeric,which do notcontribute