What are the key issues in writing “or-equal” geomembrane specifications?

Part 2. An example of an “or-equal” spec gone bad and how it applies to geomembrane specifications.

“Impermeable” is a common, assumed descriptor of a 21st century geomembrane. We use impermeable barrier materials because they are relied upon to prevent the passing of liquids when used in a variety of engineered projects where a barrier is necessary. Geomembranes are specified for these projects because they are lightweight, easy to install, cost-effective and reliable. To ensure you are selecting the right geomembrane for the application, it’s important to look at testing results for vapor/solvent transmission and puncture resistance, as well as real-world performance.