Performance of refractories significantly influence the lifetime of a glass tank and the quality of glass, thus determining the economic feasibility of the glass making process. Therefore, it is necessary to prove several characteristics essential for the behaviour of refractory material in glass tank prior to its application. The choice of refractory to be finally used based on the result of such tests is going to be right only when appropriate test methods have been applied for its characterisation and the understanding of interrelations between properties of refractories and their performance is provided. Some test methods enabling the relative assessment of glass defects formation potential of refractories, such as corrosion, blistering and knots are briefly described and evaluated regarding the meaning of the results. Taking exudation behaviour as an example, some considerations on the choice of testing methods and their limitations are presented in comparison to the methods standardised and recommended by TC 11 of ICG. A guide for refractory users in glass melting regarding the appropriate interpretation of characteristics, as given in data sheets, their meaning and assessment is provided. The interpretation restrictions originating from the need to differentiate between behaviour observed under lab test conditions and that in a real tank are also formulated in concluding remarks.
