The temperature of the specimens shall be stabilized at 25 °C ± 3 K. Following stabilization, with the specimens in the test chamber, the relative humidity shall beincreased to not less than 95 % RH at an ambient temperature of 25 °C ± 3 K.7.3 Description of the 24 h cycle7.3.1 The temperature of the chamber shall be raised to the appropriate upper temperatureprescribed by the relevant specification. The upper temperature shall be achieved in a period of3 h ± 30 min and at a rate within the limits defined by the shaded areas in Figures 2a and 2b.During this period, the relative humidity shall not be less than 95 % RH. During the last 15 minit shall not be less than 90 % RH.7.3.2 The temperature shall then be maintained within the prescribed limits for the uppertemperature (±2 K) until 12 h ± 30 min from the start of the cycle.During this period, the relative humidity shall be 93 % RH ± 3 %RH. During the first and last15 min it shall be between 90 % RH and 100 % RH.7.3.3 The temperature shall then be lowered in accordance with one of the two variants givenbelow.The temperature shall be lowered to 25 °C ± 3 K within 3 h to 6 h. The rate of fall for the firstone and one half hours shall be such that, if maintained as indicated in Figure 2a, it wouldresult in a temperature of 25 °C ±3 K being attained in 3 h ± 15 min. The relative humidity shallbe not less than 95 % RH. During the first 15 min it shall be not less than 90 % RH.7.3.4 The temperature shall then be maintained at 25 °C ± 3 K with a relative humidity of notless than 95 % RH until the 24 h cycle is completed