Challenges in developing a moisture metric to assess air change rates

Abstract

Air change rates are difficult to measure in naturally ventilated buildings. There is incentive to develop alternative techniques to measure air change rates. Using a moisture metric is a possibility, but this is challenging as it requires the ability to quantify processes that affect the moisture balance in a room. This paper consolidates literature about how the moisture balance can be understood in field studies in terms of moisture generation, moisture buffering, and ventilation. Moisture generation rates have been reported in literature with some disparity. Moisture buffering is difficult to account for due to the complexity of the process in real buildings. Ventilation can be measured using tracer gas techniques, but these often provide a 'snapshot' of the air change rate which varies both spatially and temporally in buildings. However, a promising approach has been identified whereby moisture and ventilation conditions are examined over a longer period of time i.e. weeks.Peer-review under the responsibility of the organizing committee of the ICMB21.