Time of wetness in tropical climate: Considerations on the estimation of TOW according to ISO 9223 standard

This work was focused on the discrepancies between the TOW determined according ISO 9223 standard and data obtained for indoor and outdoor conditions in humid tropical climate. It was observed that for temperatures higher than 25 °C the determination of TOW changed. Some proposals are made based on the results obtained in the present research conducted in Cuba and Mexico in order to improve the estimation of TOW. Such proposals take into account the linear relationship between time of exposure and TOW, the effect of rain, the role of air contaminants, temperature and the differences between outdoor and indoor exposure conditions.