This document specifies three methods for the determination of the bulk density of granular refractory materials (grain density) having a grain size larger than 2 mm: Method 1: mercury method with vacuum; Method 2: arrested water absorption method; Method 3: vacuum method with spin dryer option according to ISO 5017. Method 1 is intended as the reference method. NOTE Depending on the nature of the material tested, the three methods can give different results. Any statement of the value of a bulk density can therefore be accompanied by an indication of the method used or to be used in case of dispute. The same method can be used for the determination of the volume of the sample, for selecting and preparing the sample, for calculating the bulk density and for presenting the test report.