NOTE 1 There are three kinds of test methods for thermal shock, namely a rapid cooling method, a rapid heating method, and the rapid heating-cooling method. Ceramics are sensitive to tensile stress, and the surface region has many defects which act as the starting points to which strength falls. For this reason, the rapid cooling method where the maximum tensile stress is generated on the surface serves as the severest test condition for ceramics. Therefore, this International Standard specifies the rapid cooling method.

NOTE 2 In many thermal-shock test methods, liquid or gas is needed as a cooling medium, and liquid is more efficient than gas in the cooling capability. Therefore, in this International Standard, water is specified as a cooling medium.