ISO 24117:2020

This document establishes requirements for the use of the glass designations "clear glass" and "ultra-clear glass" for non-coloured glass items according to their clarity and iron content. It specifies a procedure for measuring the clarity of glass items by means of a spectrophotometer.
This document is applicable to
-  mineral glasses, and
-  glass items where a part is not covered by coating or decoration, and is therefore available for sampling.
This document is applicable to the use of glass as tableware, giftware, jewellery and luminaries.
It is not applicable to the use of glass in the context of building, watches, containers, medicine and laboratories, and to other technical uses of glass.