4.10 Temperature riseThe ambient air temperature shall be measured by means of at least two thermometers or thermocouple equally distributed around the sample at approximately half its height and at a distance of approximately 1 m from the sample. The thermometers or thermocouple shall be protected against air current and heat radiation.The ambient temperature during the test shall be between +10℃ to 40℃.The test shall be made for a time sufficient for the temperature rise to reach a constant value. In practice, this condition is reached when the variation at all measured points (including the ambient air temperature) does not exceed 1K/h.At the end of the test, the temperature rise shall not exceed the values specified in Table 2.