Long-term investigation of moisture environment in underground civil air defence work

Moisture becomes problematic in underground civil air defence work because of heavy rusting of protection equipment, mould and construction deterioration. This study conducted long-term measurement of the heat and humidity environment in a residential and a non-residential underground civil air defence work in Beijing. The thermal environment was very stable at a good level except in some summer days in the non-residential civil air defence work because of moisture insulation in summer and straw board interior wall furnishing, whereas it was very severe and varied with changing outdoor conditions in the residential civil air defence work. The humidity environment in the residential civil air defence work was wet or very wet (RH > 80%) for over 20% of the year, which may cause mould growth and surface condensation, because of low indoor temperature in winter and occupant activities and natural ventilation in summer. The findings of this study may prove important in elucidating the formation mechanism of thermal environment in civil air defence work and to develop appropriate desiccant solutions.