ASTM D7348-13

5.1 LOI refers to the mass loss of a combustion residue whenever it is heated in an air or oxygen atmosphere to high temperatures. In the cement industry, use of the term LOI normally refers to a mass loss in a sample heated to 950°C. To combustion engineers, the term LOI normally refers to mass losses in samples heated to temperatures normally less than 950°C. These test methods establish a procedure for determining LOI values for combustion residues heated to 750°C or 950°C. LOI values from these test methods can be used by industries that utilize combustion residues in various processes and products.

5.2 If the solid combustion residue is heated to estimate the combustible or unburned carbon in the sample, it has been shown that LOI and estimation of unburned carbon do not necessarily agree well with each other and that LOI should not be used as an estimate of unburned carbon in all combustion residues.5.3 If the solid combustion residue is heated to prepare an ash for the determination of the concentrations of major and minor elements, use the heating procedure described in Test Methods D3682, D4326, and D6349, or the procedures for the 750°C LOI determination described in these test methods (Method A).

5.4 If the solid combustion residue is heated to prepare an ash for the determination of the concentrations of trace elements, use the heating procedure described in Test Methods D3683 and D6357.