Laboratory test method for determining gas permeation through double welded geomembrane seams

Abstract

Since nothing is absolutely impermeable, the knowledge of the permeability coefficients of geomembranes to gases or liquids is required to assess its effectiveness, especially in the seamed area. In order to determine the permeance of double welded high density polyethylene geomembrane seams to nitrogen and water vapour, laboratory tests have been carried out. Tests have been conducted using a permeation cell, designed to allow the immersion of each seamed specimen either in water or in air. The space between the two parallel welds was filled with nitrogen gas under a given pressure and the decrease of this pressure with time was monitored. The first results show that it is possible to characterise the seam by a permeance depending on the fluid and on the seam parameters. This suggests that the gas permeation test might be used to detect the quality of seams by quantitative measurement of the permeance.