The purpose of this study was to determine the thermal comfort requirements for steps in temperature. Thirty male subjects were exposed for 50 minutes to a 34 or 37°C condition, and then quickly transferred to a cooler environment of 31, 28, 25, and 22°C for 50 minutes.Mean skin temperature was continuously measured, and the subjects reported their thermal sensation and comfort sensation every 2 minutes. Just after the step changes, the mean skin temperature immediately decreased, while the thermal sensation overshot and gradually rose again. Both the skin temperature and the thermal sensation seemed to reach a constant level within about 20 minutes. However, there were differences in the mean skin temperature and the neutral temperature derived from the correlation between the ambient temperature and the thermal sensation even 50 minutes after the steps, due to the thermal environmental condition before the changes of temperature. The change in the neutral temperature with time was expressed as two attenuating equations. These equations indicate that there is an obvious difference between the neutral temperatures due to the thermal condition before step changes, and that it takes more than 50 minutes after the step changes to reach the steady state. It is expected that these equations predict in quantitative terms the thermal comfort requirements within a given experimental condition.

The purpose of this study was to ascertain the actual conditions of the thermal environment and the symptoms of patient and staff (nurses and nurses' aides) during winter in a hospital. We measured the ambient temperature and humidity in sickrooms, nurse stations, and corridors. The subjects included 36 patients and 45 staff members. The existence of low humidity environments (relative humidity was less than 40%) in a hospital during winter was confirmed, and the levels of low humidity reached those known to promote the spread of influenza viruses. Thermal comfort of patients was not directly connected to the low humidity in sickrooms. However, 54.9% and 73.4% of patients were conscious of itchy skin and thirst, respectively. The majority of the staff members were working with itchy skin and thirst. These results suggested that extreme low humidity in a hospital during winter presents problem that should be solved quickly.

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