Occupant body movement and seat occupancy rate for design of desk micro-environment

Occupant’s body movement and seat occupancy rate are some of the factors important for optimal design of desk micro-environment, including personalized ventilation. A system for identification and recording occupant’s presence and body movement at the desk was designed. The detection system consisted of set of five infrared detectors and a non-contact laser distance meter. The system was used in an office building. In total 11 occupants participated in the survey. Each occupant was monitored during one standard working day. Occupants spent approximately 70 % of the working time at the desk. In average occupants left the desk 4.6 times during the day and stayed away in average for 20 min. The average distance between the PC monitor and the occupant body was 0.63 m and changed mainly from 0.48 m to 0.72 m. 78% of the time the length of occupants’ body movement to the left/right direction was less than 0.225 m, with maximum span of the whole interval up to 0.75 m. In average the frequency of body position change was 4.9 times per minute, with minimum frequency of 0.6 times per minute and maximum frequency of 11.9 times per minute. The collected data are discussed and requirements for optimal design of desk micro-environment are suggested.