NEN-EN 13373:2018 Ontw. en

This document describes methods for verifying the geometric characteristics of products of natural stone such as rough blocks, rough slabs, finished products for cladding, flooring, stairs and modular tiles and paving units (slabs, setts and kerbs). These methods can be applied in the case of a dispute between two parties, they are not compulsory for production control. Other measuring equipment can be used as long as their precision can be demonstrated to be equal or better than the ones mentioned here. It is essential that all weighing, measuring and testing equipment are calibrated or retraceable to measurement standards and regularly inspected according to documented procedures, frequencies and criteria. It is important that the expression of the dimensional characteristics is in accordance with the appropriate class of the measured product.