1、Designation:D740812(Reapproved 2020)Standard Specification forNon-Reinforced PVC(Polyvinyl Chloride)GeomembraneSeams1This standard is issued under the fixed designation D7408;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year o
2、f 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 specification covers the minimum values for seamsfabricated into unreinforced PVC geomembranes in factoryand field a
3、pplications.1.2 This specification covers PVC geomembranes in thick-ness of 0.25 through 1.52 mm(0.010 through 0.060 in.).1.3 In addition to structural characteristics,the specifiershall evaluate other characteristics beyond the scope of thisspecification that affect the final choice of construction
4、.Theseinclude,but are not limited to,functional,legal,insurance,andeconomic considerations.1.4 This specification is not intended to exclude products orsystems not covered by the referenced documents.1.5 The values stated in inch-pound units are to be regardedas standard.The values given in parenthe
5、ses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 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 safe
6、ty,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of In
7、ternational Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D638 Test Method for Tensile Properties of PlasticsD882 Test Method for Tensile Properties of Thin PlasticSheetingD4439 Terminol
8、ogy for GeosyntheticsD7176 Specification for Non-Reinforced Polyvinyl Chloride(PVC)Geomembranes Used in Buried Applications3.Terminology3.1 Definitions:3.1.1 adhesive or bodied solvent,nthese seams are typi-cally produced by applying an adhesive to both sides of thesheet to be bonded and then pressu
9、re is applied to the top sheetwith the bottom sheet supported by a flat,firm surface.3.1.2 chemical fusion seams,nuse of a chemical agent todissolve the surface of the geomembrane for bonding.3.1.3 hot air or knife,nthis technique melts the twogeomembrane surfaces to be seamed by running a hot metal
10、wedge or hot air between them.Pressure is applied to the topor bottom geomembrane,or both,to form a continuous bond.These seams are usually produced with a combination of ahand-held heat gun or hand-held hot wedge along with a handroller.3.1.4 thermal fusion,nalso known as hot air or hot wedge,this
11、technique introduces high-temperature air or gas or a hotwedge between two geomembrane surfaces to facilitate melt-ing.Pressure is applied to the top and/or bottom sheets of thegeomembrane,forcing together the two surfaces to form acontinuous bond.3.1.4.1 DiscussionSome seams of this kind are made w
12、ithdual bond tracks separated by a non-bonded gap.These seamsare referred to as dual-track seams or double-track seams.3.2 For definitions of other terms,see Terminology D4439.4.Classification4.1 Types of seams covered in this specification:4.1.1 Chemical fusion,4.1.2 Adhesive or bodied solvent,4.1.
13、3 Dielectric,and4.1.4 Thermal fusion.5.Significance and Use5.1 SignificanceThe increased use of geomembranes asbarrier materials to restrict fluid migration from one location to1This specification is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Sub
14、committee D35.06 on Geosyn-thetic Specifications.Current edition approved Feb.15,2020.Published February 2020.Originallyapproved in 2008.Last previous edition approved in 2012 as D7408 12.DOI:10.1520/D7408-12R20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Custom
15、er 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 StatesThis international standard was developed in a
16、ccordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 Copyright by ASTM Intl(all rights reserved);Tue Feb 25 22:11:33 EST 2020Downloaded/printed byPurdue University Libraries(Purdue University Libraries)pursuant to License Agreement.No further reproductions authorized.another in vari
