A new type of environmental test chamber, designed specifically for the study of the effect of thermal environment on man's comfort and physiological reactions, is described in this paper.

The four principal environmental factors affecting man are air temperature, humidity, air movement and radiant heat; each of which must be controlled independently during any investigation of man's physiological and sensory response to his thermal environment. Furthermore, the precise control of each factor is necessary both during the steady state and dynamic changes. Finally, the size of working area must satisfy requirements for a useful number of subjects and their supporting physiological test equipment.

A chamber using the principles described below was designed and constructed in 1972 at the Technical University of Denmark, replacing an older chamber (1). Both of these chambers were designed by P. Kjerulf-Jensen. In 1973 he joined a group at the John B. Pierce Foundation Laboratory in New Haven with the purpose of designing a chamber generally based on the same principles. The following description refers primarily to the Pierce chamber but also essentially covers the Danish chamber.

The test chamber was designed to fit the overall space 30 ft x 30 ft x 14 ft formerly used for the all-weather test room, constructed in 1938 (2).

A final objective of the present project was to use readily available manufactured equipment or design and fabricate the whole system, including all controls, with resources available in our local machine and electronic shops, both of which were modest in technical facilities available.