A ‘Lot’ is meant for the quantity of refractory materials from which sample specimens are drawn for inspection. The test results of these samples make the basis for acceptance or otherwise of the refractory lot. Since Refractories are characteristically anisotropic in nature so instead of drawing only one sample, a predefined number of sample refractory specimens are collected from the lot while sampling. Although there are provisions for ‘Hundred Percent Inspection’ and ‘Sampling Inspection’ but, hundred percent inspections is not preferred generally since most of the tests are destructive type besides, consideration of factors like time consumption and the costs involved. .
Drawing refractory samples commonly known as Sampling of Refractories is an important function done before inspection. The inspection procedure starts by selecting, generally a minimum number of units, called a ‘Sample’, from the refractory lot.