ASTM_D_4446_-_D_4446M_-_13.pdf

Designation:D4446/D4446M13Standard Test Method forAnti-Swelling Effectiveness of Water-Repellent Formulationsand Differential Swelling of Untreated Wood When Exposedto Liquid Water Environments1This standard is issued under the fixed designation D4446/D4446M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method is designed to evaluate the effective-ness of water-repellent compositions for retarding dimensionalchanges in coated wood submerged in water.It can also be usedto measure the differential swelling of untreated wood whenexposed to liquid water environments.The compositions testedare designed to be mixed until uniform and applied by brush,roller,dip or spray to an exterior wood surface.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.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.Summary of Method2.1 Wood samples in the form of elongated slats thatrepresent the timber species or product/treatment combinationto be evaluated are exposed in soak containers.The elongatedslats are immersed in the water-repellent formulation,condi-tioned with appropriate weighing,then subjected to immersionin distilled water for a prescribed period.The untreated slatsomit the immersion in the water-repellent formulation.Theswelling resulting from immersion for the selected time periodis determined by reading a dial gage calibrated in increments of0.025 mm 0.001 in.2.2 A water repellent efficiency of 60%is required to passthis test.3.Significance and Use3.1 This test method is useful in determining the relativeanti-swelling efficiency of various water-repellent formulationswhen applied to wood.It is the initial means of estimating theability of water-repellent treated wood to perform satisfactorilywhen exposed to liquid water environments.3.2 The swelling differences of untreated wood specieswhen subjected to water immersion can also be determined bythis test method.3.3 This method is a basic screening test and thus providesan initial determination of the anti-swelling efficiency of waterrepellents.It is a qualitative method designed to provide areproducible means of establishing:(1)the anti-swelling effi-ciency of water-repellent formulations,and(2)the relativeswelling of untreated wood species when both are exposed toliquid water environments.4.Apparatus4.1 Conditioning Room or Chamber,having a controlledtemperature of 23 6 2C 73.5 6 3.5F,and a controlledrelative humidity of 50 6 5%.This room is used to establisha uniform moisture content in the test specimens.In all studiesthe temperature and relative humidity selected by the investi-gator must be stated and must remain constant throughout agiven conditioning and test period.4.2 Balance,sensitive to at least 0.01 g.4.3 Treating Tank(Fig.1).4.4 Swellometer,as illustrated in Fig.2,Fig.3,and Fig.4.Apparatus can be built to be used for both 5 in.and 10 in.wafers.5.Test Specimens5.1 Wood used for these tests must be straight-grained,flat-sawn,clear,kiln-dried Ponderosa pine sapwood or othersuitable species.Cut the parent boards in a manner to givespecimens 6 mm 14in.in the longitudinal dimension,38 mm112in.in the radial dimension,and 254 mm 10 in.or 127mm 5 in.in the tangential dimension.Cut with a sharp,1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved Nov.1,2013.Published December 2013.Originallyapproved in 1995.Last previous edition approved in 2012 as D4446 08(2012).DOI:10.1520/D4446_D4446M-13.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 fine-toothed saw to obtain as smooth a surface as possiblewithout sanding.Number each specimen for identification andreference.5.1.1 Selection of Ponderosa pine sapwood can be assuredby the following quick chemical test:(1)prepare a solution of5 g of benzidine in 25 g of hydrochloric acid and 970 g ofwater,and(2)prepare a second solution consisting of a 10%concentration of sodium nitrite in water.When the test is to bemade,pour equal amounts of the two solutions together andthen apply to the wood surface by means of brushing ordipping.The sapwood immed