Bulk density: This is represented by the weight per unit volume of the refractory of (g/cm^{3}). This volume includes the volume of the pores space, therefore, higher the bulk density. It affects many other properties, for example, a higher bulk density, improves volume stability, strength, heat capacity and sampling resistance. Low bulk density material is required for insulating refractory.
Bulk density
B = D/W = D/W-S