1、Designation: D7433 13Standard 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 la
2、st 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 ofa
3、n 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 pan
4、els including, but not limited to, plywood(such as MDO grades and HDO grades referenced in PS 109),oriented strand board, medium density fiberboard,particleboard, and hardboard.1.3 This test method does not address sampling procedures,number of replications nor performance criteria since thosedetail
5、s 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
6、 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
7、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 Wat
8、erAbsorption 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 absorp
9、tiveness 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 ove
10、rlaid 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.NOTE 1P
11、anel 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 Wooda
12、nd 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.as
13、tm.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 20899-107
14、0, http:/www.nist.gov/standardsCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. 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 b
15、e 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.NOTE 2A steel pocket scale with etched gradu
16、ations 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
17、 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 to the assembly wei
18、ght change through absorptionof water.4.8 Aluminum foil or other sheet material that will form avapor resistant seal.5. Test Procedure5.1 Specimen Preparation:5.1.1 When a standardized dry initial condition is required,the panels shall be brought to moisture equilibrium in aconditioned environment o
19、f 20 +/-6 C (68 +/- 11 F) and 65%(+/- 5%) relative humidity.NOTE 3Depending upon the purpose of the tests, other panel moistureconditions are permitted.5.1.2 The initial panel moisture content of adjacent speci-mens shall be measured in accordance with Test MethodD4442.5.1.3 Cut overlaid panel test
20、specimens to 150 150 mm(6.0 6.0 in.).5.1.4 Measure the inside diameter of the ring to the nearest0.5 mm (0.02 in.).5.1.5 Apply a bead of silicone or elastomeric sealant to theend of the ring.NOTE 4The bead of sealant should be approximately 3 mm (0.125 in.)for suitable performance.5.1.6 Center the r
21、ing over the face of the specimens, thenpress and position the ring against the specimen to obtain agood seal.5.1.7 Allow the sealant to cure for a minimum of 48 hoursat 20 +/-6C (68 +/-11F).5.1.8 Seal all specimen surfaces of the specimen outside ofthe ring by dipping the specimen into a molten mix
22、ture of 50 %beeswax and 50 % rosin or other sealant with equivalent waterrepellancy.5.2 Specimen Exposure to Water:5.2.1 Determine the mass of the specimen to an accuracy of0.01 gram. Place the specimen on a level surface. Fill the ringwith water to a depth of 25.4 mm with a tolerance of +0.5/-0.0mm
23、 (1 in., + .02/-0.00 in.). Measure and record the waterdepth.5.2.2 Cover the ring with aluminum foil or other suitablevapor barrier to prevent evaporation.5.2.3 Measure and record the height of the water columnafter soaking for 24 h, +0.2/-0.0 h. Add water if needed toreturn the water level to 25.4
24、mm with a tolerance of +0.5/-0.0mm (1.00 in., +0.02/-0.00 in.).5.2.4 Measure and record the height of the water columnafter soaking for a total of 48 h, +0.2/-0.0 h. Empty the waterfrom the rings and blot the area dry.5.2.5 Determine the mass of the specimens to an accuracy of0.01 g.5.3 Calculate th
25、e water absorption through the surface.5.3.1 Calculate the area of the overlay exposed to wettingfrom the measured inside diameter of the pipe.5.3.2 Compute the water absorption (WA48) as follows:WA485 F 2 I!/A (1)where:WA48= Water absorption at 48 h, gram/m2,F = mass of specimen after 48-h soak, g,
26、I = mass of specimen before exposure to water, g,A = area of specimen exposed to wetting, m2.6. Report6.1 Report the following information for each test.6.2 The initial moisture condition and moisture content ofthe panel specimens.6.3 A description of the overlay.NOTE 5The relevant descriptive detai
27、ls of the overlay will varydepending upon the purpose of the test, but should include informationsuch as manufacturer, resin loading, thickness.6.4 A description of the substrate panel.NOTE 6The relevant descriptive details of the panel substrate willvary depending upon the purpose of the test, but
28、should include informa-tion such as manufacturer, panel type, wood species of the surface layer,thickness, panel grade or grade of surface that is overlaid.6.5 Total duration of water soak to the nearest one-tenthhour.6.6 Depth of water column at beginning of soak period andat 24- and 48-h exposure
29、periods.6.7 Water absorption at 48 h, calculated as the grams ofwater absorbed per square meter.6.8 Any deviations from these methods shall be reported.7. Precision and Bias7.1 There has not been a study to determine repeatabilityand reproducibility of this method.7.2 BiasNo bias statement is availa
30、ble for this test methoddue to the lack of an acceptable homogeneous referencematerial.D7433 1328. Keywords8.1 wood-based panels; water absorption; overlays; CobbRingD7433 133ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentio
31、nedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee an
32、d must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting o
33、f theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box
34、 C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D7433 134
