Geomembrane Seam Sample Testing

Q: We occasionally receive geomembrane seam samples for testing where LLDPE is welded to HDPE. In this situation, should these samples be tested at 50mm/min. or 500mm/min.? To further complicate this, sometimes these seams are extrusion welds using either HD or LL rod. Does this influence the selection of the test method?

A: Your first question is easy to answer. Geomembrane seam samples for testing where LLDPE is welded to HDPE should be tested at 500mm/min. However, your second question deserves a bit more explanation and is complex. The short answer is yes, HD or LL rod does influence the test, but the selection of the test method remains with the parent material type (e.g., if you seam HDPE GM with LL rod, test at 50 mm/min.).