A property that is apparently very obvious to determine, such as the thickness of a geomembrane, becomes guesswork. We distinguish between average thickness and tolerance in ± a specific percentage %, according to the industrial rolling process followed.
The property is clearly defined up to this point. The client may even be convinced of actually purchasing a particular product weight equivalent to the surface by the average thickness and product density. It is a physical principle and it would enable comparing different products with one another.
The confusion arises when “nominal” thicknesses are mentioned, leaving these up to the manufacturer who “designates” his product as a specific thickness when phrases such as the average minimum thickness is the nominal thickness “less” 10% and the tolerance is -10%, appear in its description. In short, the product could actually be at least 20% of the “nominal” thickness. We’ll leave the significance of this to the discretion of the Client.