Just a few quick questions about sand gradation and nomenclature. When a manufacturer says that they supply a mesh 16-20 sand, what does this mean exactly? Is there a standard or some type of requirement that they must meet during sieve analysis to call it this sand i.e. 95% of particles between the mesh 16 and mesh 20 (unsure on nomenclature). I am writing specs. on what type of sand we can accept and there seems to be a large range of different sands (mesh 60, mesh 20-50, mesh 12-20, etc.) available but I need to know what ranges they must fall in during sieve analysis to give it these designations.