Occupant Responses and Office Work Performance in Environments with Moderately Drifting Operative Temperatures (RP-1269)

Fifty-two experimental subjects (50% female) were seated in a climate chamber and exposed to operative temperature ramps with different slopes, directions, and durations during two related experiments. The first experiment covered a temperature range of 22°C–26.8°C (71.6°F–80.2°F) and subjects wore light clothing (0.5 clo). The operative temperature was increased in rates of 0.6 K/h (1.1°F/h) (for 8 h), 1.2 K/h (2.2°F/h) (for 4 h), 2.4 K/h (4.3°F/h) (for 2 h), and 4.8 K/h (8.6°F/h) (for 1 h), respectively. In one session, subjects were exposed to a constant temperature of 24.4°C (75.9°F) (for 4 h). The second experiment covered a temperature range of 17.8°C–25°C (64°F–77°F), and subjects wore heavier clothing (0.7 clo). Temperature ramps of 0.6 K/h (1.1°F/h) (for 8 h), 1.2 K/h (2.2°F/h) (for 6 h), 0.6 K/h (–1.1°F/h) (for 8 h), and –1.2 K/h (–2.2°F/h) (for 6 h) and exposure to a constant temperature of 21.4°C (70.5°F) (for 6 h) were examined. Subjects assessed their thermal sensation, acceptability of the thermal environment, perceived air quality, and intensity of sick building syndrome (SBS) symptoms. Subjects’ performance was measured by simulated office work, including tasks such as addition, proofreading, reading and comprehension, and text typing. Results of the experiments showed that even moderately changing operative temperature ramps were sensed by sedentary subjects when exposure times exceeded 4 h. No significant effects on SBS symptoms related to local irritation of mucous membranes were found, while intensity of headache, concentration ability, and general well-being were significantly affected in most of the ramps. Linear dependence of perceived air quality on operative temperature was noted. No significantly consistent effects of individual temperature ramps on office work performance were found.