ASTM_C_1794_-_15.pdf

Designation:C179415Standard Test Methods forDetermination of the Water Absorption Coefficient by PartialImmersion1This standard is issued under the fixed designation C1794;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 defines a procedure to determine thewater absorption coefficient of a material by partial submer-sion.The scope is to evaluate the rate of absorption of waterdue to capillary forces for building materials in contact withnormal or driving rain above grade.The procedure is typicallysuitable mainly for masonry material,plaster,or a coating incombination with a substrate;but it can also be used forinsulation materials.This test method is designed to be usedonly on homogeneous materials and does not apply to materialsthat are composites or non-homogeneous(for example,FacedRigid Closed-cell Insulation).It is not within the scope of thisstandard to determine liquid uptake phenomena in below-gradeapplications.The water absorption coefficient is mainly used asan input datum for numerical simulation of the combined heatand moisture transport in building envelopes for design andforensic investigation purposes.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.However,derived results can be convertedfrom one system to the other using appropriate conversionfactors(see Table 1).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:2C168 Terminology Relating to Thermal Insulation2.2 Other Standards:3ISO 9346 Hygrothermal performance of buildings and build-ing materialsPhysical quantities for mass transferVocabularyISO 15148 Determination of water absorption coefficient bypartial immersion3.Terminology3.1 Definitions of TermsFor definitions associated withthermal insulation issues refer to Terminology C168.Fordefinitions associated with water absorption refer to the termsand definitions given in ISO 9346.3.2 Definitions of Terms Specific to This Standard:3.2.1 homogeneous material,nmaterials,which proper-ties are uniform on a macroscopic scale.3.2.2 water absorption coeffcient,nmass of water ab-sorbed by a test specimen per face area and per square root oftime(see Eq 2).3.3 Symbols and Unitsthe Symbols and Units shown inTable 2 are used.4.Summary of Test Method and Use4.1 Water absorption by partial submersion will be calcu-lated by measuring the change in weight of the specimen in asituation when the bottom surface is in contact with liquidwater within a time range of at least 24 h.Liquid water that isonly adsorbed on the surface shall not be taken into accountand shall be removed before weighing,for example.,byblotting with a sponge.4.2 The purpose is of this test is to derive reliable data onthe capillary water uptake of building materials in appropriateunits using a simple apparatus.These data can also be used asmaterial properties for hygrothermal simulation of the buildingenvelope for design and forensic purposes.5.Significance and Use5.1 The purpose of these tests is to obtain,by means ofsimple apparatus,reliable and easy to determine values of1This test method is under the jurisdiction ofASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.33 on InsulationFinishes and Moisture.Current edition approved March 1,2015.Published April 2015.DOI:10.1520/C1794-15.2For 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 American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 liquid water transport for capillary active materials expressedin suitable units.These values are for use as part of the materialproperties in hygrothermal analysis tools for building envelopedesign and forensic studies.As the topic of liquid transportphenomena in porous materials is very complex,Appendix X1in ISO 15148 shows some more detailed background informa-tion.6.Apparatus6.1 The apparatus must contain the following:6.1.1 Ascale to measure the weight of the spec