A suitable liquid hear-transfer medium(*2)for the test specimen immersion shall be well stirred during the test and shall be provided with a means of raising the temperature at a uniform rate of 2±0.2℃/min. This heating rate shall be considered to be met if, every 5-min, interval during the test, the temperature of the bath rises 10±1℃ at each specimen location. Immersion bath temperature when starting the test shall be 40℃ or below.