Definition : Pyrometric Cone Equivalent (P.C.E.) - In the case of refractories, the number of that standard cone whose tip would touch the supporting plaque simultaneously with a cone of the material being investigated when tested in accordance with the Standard Method of test for P.C.E. of Fireclay Bricks IS: 1528 Part-I 1980 of the Indian Standard Institute.
Note: The terms fusion point, Softening point, deformation point and melting point have heretofore been lossely used for pyrometric cone equivalent.

*Note: Pyrometric cones do not give an accurate measurement of temperature. Where it is desired to interpret P.C.E. values approximately in terms of temperature, The table above may be used. This table had been approved by the A.S.M.T. based on the work of Fairchild and peters, J. Amer. Cer. Soc. 9, 701-43, 1926. Revision in the A.S.M.T. cones 12 to 37 inclusive were adopted in June, 1955, A.S.M.T. Standards 1955, 711.715 Heating rate: Cones 022 to 37 inclusive, 150ºCent. Per hour (270ºF per hour); Cones 38, 100º Cent. Per hour (180ºF per hours). The temperatures do not apply to the slower of heating common in the commercial firing and to use of refractory materials. This chart as been adopted by bureau of Indian Standards.