ASTM_D_4545_-_86_1999.pdf

Designation:D 4545 86(Reapproved 1999)Standard Practice forDetermining the Integrity of Factory Seams Used in JoiningManufactured Flexible Sheet Geomembranes1This standard is issued under the fixed designation D 4545;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice is intended as a summary of destructiveand nondestructive quality control test methods for determin-ing the integrity of factory fabricated seams used in the joiningof flexible sheet materials.This practice outlines the testprocedures available for determining the quality of bondedseams.Tests chosen to be performed shall be selected from thenondestructive and destructive tests for their specificity to theliner system and the design application.These test methods areapplicable to the seaming methods commonly used on manu-factured flexible sheet geomembranes that are scrim-reinforcedor nonreinforced.1.2 The types of factory seams covered by this practiceinclude the following:1.2.1 Thermally Bonded Seams:1.2.1.1 DielectricAdielectric seam is produced by clamp-ing two lapped sheets of polymeric membrane between twoconductive bars and applying an electric current to the bars,thus producing a field that generates friction heat at theinterface between the two sheets to melt the surfaces.Thepressure of the clamping bars creates a homogeneous bondwhich is allowed to cool by cutting off the electric current,while still under pressure.1.2.1.2 Hot AirA hot air seam is produced by applyinghigh temperature air or gas between two polymeric sheetsurfaces,thus melting the surfaces,at which time pressure isapplied to form a homogeneous bond between the two mem-brane surfaces.1.2.1.3 Hot Wedge(or Knife)A hot wedge seam is pro-duced by melting the two intimate surfaces by running a hotmetal wedge between the surfaces,followed immediately bypressure to form a homogeneous bond.1.2.1.4 ExtrusionA bond seam is produced by extrudingmolten parent material between or at the edge of two over-lapped polymer sheet materials to effect a homogeneous meltbetween the two sheets to be joined.Hot air is sometimesapplied between the two sheets to bring their temperature closeto the melt point.The extrudate heat then melts the twopreheated surfaces to effect the homogeneous bond.1.2.2 Solvent Bonded SeamsA solvent is used to softenthe surfaces to be bonded,followed by pressure to form ahomogeneous bond.1.2.3 Bodied Solvent Bonded SeamsThe parent liningpolymer material is dissolved in a solvent that is then appliedin the same manner as a straight solvent,thus effecting ahomogeneous bond.1.2.4 Cured or Vulcanized SeamsThese are thermallybonded seams that are produced prior to vulcanization of acured ribbon sheet.Ahomogeneous bond is obtained by curingthe seam along with the parent material blanket.1.2.5 Adhesive Bonded or Cemented Seams,Taped Seams,and Waterproofed Sewn SeamsThese seams are rarely madeat the factory during the fabrication process and are generallylimited to field installation seams.Adhesive bonded and tapedseams provide a means,although nonhomogeneous,of joiningcured sheets.Waterproofed sewn seams are used with geotex-tiles,which may be laminated to a geomembrane film.1.3 The types of factory seams covered by this practiceinclude the following seam constructions:1.3.1 Lap SeamsOne sheet overlaps the other by a rec-ommended minimum amount,with the bonded area between orat the edge of the two sheets.1.3.2 Cap-Stripped SeamsA separate strip of the parentsheet material is bonded to both sheets covering the lap seam.1.3.3 Butt Seams,Envelope Seams,and Standing SeamsThese seams are not commonly used in factory seam fabrica-tion.1.4 The values stated in SI units are to be regarded as thestandard.1.5 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:D 413 Test Methods for Rubber PropertyAdhesion toFlexible Substrate2D 618 Methods of Conditioning Plastics and ElectricalInsulating Materials for Testing31This practice is under the jurisdiction of ASTM Committee D-35 on Geosyn-thetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.Current edition approved March 3,1986.Published May 1986.2Annual Book of ASTM Standards,Vol 09.01.3Annual Book of ASTM Standards,Vol 10.01.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.D 751 Methods of Testing Coated Fabrics4D 816 Methods of Testing Rubber Cements33.Significance and Use3.1 The increased use of geomembranes as barrier materialsto restrict liquid mi