States that in many cases air flow rates through microenvironments (eg zones within a room) are unknown and vary considerably from mean room (macroenvironmental) conditions. Describes a steady-state calorimetry method to estimate the ventilation rate in an air space. States the method can be applied not only to enclosed, mechanically ventilated air spaces but also to less enclosed air spaces such as rooms with a door open or a zone within a room. Validates the method by laboratory experimentation. Note that the method is more appropriate for small air spaces such as zones within a room, where thermal capacitance effects are of little influence. Discusses limitations of the method.

KEYWORDS: Measuring, steady state, air flow, rooms, ventilation, experiment