Properties of good refractory material: The requirements of refractories for different furnaces and heating places depend on the working conditions. Nature of slag formed, maximum temperature required, refractoriness under load, abrasion resistance, resistance to thermal shock, thermal conductivity etc. For examples, in acid convertors, the lining is to be made with acid refractories, whereas basic furnaces are to be lined with basic refractories. In order to access the suitability of refractories for particular applications, their various properties should be tested.