This Yart of EN 993 specifies a method for determiningThe resistance of dense shaped refractory prnducts to attack by sulfuric acidSulfuric acid is used since it gives results which are typical of the results of exposing refractory materials to many acids (other than hydrofluoric acid).
EN 993-16:1995 history
1995EN 993-16:1995 Dense shaped refractory products - Methods of test - Part 16: Determination of resistance to sulphuric acid