This part of ISO 4597 specifies a method of designation for epoxy resin hardeners and accelerators. The object of this designation method is to allocate to each commercial product a group of digits, called the “designation”, giving in a coded form certain information on the product: chemical base, modifiers and solvents, viscosity and additives. Thus all products having similar properties and therefore likely to have the same uses will have the same designation, so aiding users in their choice if producers list the designation in their data sheets.