ASTM_D_7408_-_12.pdf

Designation:D740812Standard 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 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 specification covers the minimum values for seamsfabricated into unreinforced PVC geomembranes in factoryand field applications.1.2 This specification covers PVC Geomembranes in thick-ness of.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.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 parentheses 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D638 Test Method for Tensile Properties of PlasticsD882 Test Method for Tensile Properties of Thin PlasticSheetingD4439 Terminology for GeosyntheticsD7176 Specification for Non-Reinforced Polyvinyl Chloride(PVC)Geomembranes Used in Buried Applications3.Terminology3.1 Definitions:3.1.1 chemical fusion seams,nuse of a chemical agent todissolve the surface of the geomembrane for bonding.3.1.2 adhesive or bodied solvent,nthese seams are typi-cally produced by applying an adhesive to both sides of thesheet to be bonded and then pressure is applied to the top sheetwith the bottom sheet supported by flat a firm surface3.1.3 thermal fusion,n also known as hot air or hotwedge,this technique introduces high-temperature air or gas ora hot wedge between two geomembrane surfaces to facilitatemelting.Pressure is applied to the top and/or bottom sheets ofthe geomembrane,forcing together the two surfaces to form acontinuous bond.3.1.3.1 DiscussionSome seams of this kind are made withdual bond tracks separated by a non-bonded gap.These seamsare referred to as dual track seams or double-track seams3.1.4 hot air or knife,n this technique melts the twogeomembrane surfaces to be seamed by running a hot metalwedge 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.3.2 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,4.1.3 Dielectric,and4.1.4 Thermal Fusion.5.Significance and Use5.1 Significance the increased use of geomembranes asbarrier materials to restrict fluid migration from one location toanother in various applications,and the various types ofseaming methods used in joining geomembrane sheets,hascreated a need to standardize minimum seam strength require-ments.1This specification is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomem-branes.Current edition approved July 15,2012.Published September 2012.Lastprevious edition published 2008 as D740808.DOI:10.1520/D7408-12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 UseStandard seam specification provides informationas to the status of the seam.Data obtained by this standard canbe used in CQC/CQAdocuments.This test method is useful forspecification testing and for comparative purposes but does notnecessarily measure the ultimate strength that the seam mayacquire.6.Apparatus6.1Tensile instrumentation shall meet the requirementsoutlined in Test Method D638.6.2 Grip FacesGrip faces shall be a minimum 25 mm(1in.)wide and a minimum of 25 mm(1 in.)in length.Smoothrubber,fine serrated or coarse serrated grip faces have all beenfound to be suitable for testing geomembrane seams.7.Sample Preparation7.1 Cut a sample large enough to accommodate the removalof five(5)peel specimens and five(5)shear specimens(useFig.1)NOTE1Larger sa