PVC Geomembrane Research Negates Film Tearing Bond Requirement

Current research being done at EPI with PVC Geomembrane demonstrates the physical characteristics of PVC Geomembrane material outperforms normal design criteria. This paper will show that PVC Geomembrane seams can acclimate to 200% elongation without an issue in the integrity of the seam. PVC Geomembrane can accommodate 200% movement without failure. If the landfill or containment project can't accommodate 200% movement without catastrophic failure, why are we trying to make FTB seams in PVC Geomembrane that don't reach failure until +400% elongation? Film tearing bond(FTB) has been preached by the geomembrane industry as the minimum standard criteria for years. FTB is required of HDPE materials requiring the seam to be stronger than the material itself, while the material has functional elongation less than 20%. This simply isn't the case with PVC because of its high elongation, ability to conform and adjust to minor soil movement. PVC Geomembrane material with a normal strength seam of about 10 lbs per inch width can withstand 200% elongation without seam failure. Requiring the welding process to create FTB in the seam at the expense of raw material properties sacrifices the ultimate goal of geomembrane integrity. A wide sampling of seams in 0.75mm and 1.0mm PVC Geomembrane have been elongated and held at 100% and 200% elongation in a custom built apparatus for over a year. No failures in any of the variety of seams have been observed to date in this ongoing test. The research conducted by EPI will be presented in this paper.