Measuring and modeling moisture environment in underground metro stations during commissioning stage: A case study

Due to the humid underground environment, underground metro stations often have internal condensation issues, especially during the commissioning and initial operation phases, and these issues will have a negative impact on the equipment operation and building life. This study aims to solve the issue by 1) identifying common areas with condensation risks based on on-site measurements and numerical simulation methods, and 2) proposing effective dehumidification solutions for the moisture control of stations. By on-site investigating the characteristics of the station’s moisture environment and numerical assessing the effects of two different dehumidification strategies, it has been found that 1) for Tianjin, during most times in summer, the air temperature of the station in the commissioning phase was maintained relatively stable, but with significantly changing humidity; 2) the relative humidity on the platforms was higher than 80% for almost 30% of the testing time, and the surface of the upper structure of platform doors having a high risk of condensation; 3) the dehumidification effect of industrial dehumidifiers was found to be better than that of increasing exhaust air volume. The authors hope that the research could aid the decision on dehumidification strategies and provide guidance for further moisture control in underground stations. Practical Application This article analyzed the moisture environment of the underground metro stations in the commissioning phase and conducted a numerical approach to assess the condensation risk. Potential dehumidification solutions including increasing the exhaust air volume and using industrial dehumidifiers have been proposed, and their effects have been investigated and compared. The authors hope that this research can aid the decision on dehumidification strategies for facilities maintenance and provide a guidance to further moisture control in underground stations.