The multi-axial burst test is a tool that the design engineer can use in assessing the performance of HOPE geomembranes as landfill caps, where subsidence is problematic. In this test, pressure is applied perpendicularly to the surface of the geomembrane ,ps would be the case in real life applications. Results from the multi-axial te t confirm the results .of the uni-axial tensile test for HOPE up to the yield point, but show that tensile break and ultimate elongation are not relevant to the liner’s performance.