Effect of Ambient Pressure on Equilibrium Moisture Content of Wood


  • Honghai Liu
  • Lin Yang
  • Yingchun Cai
  • Masatoshi Sugimori
  • Kazuo Hayashi


Equilibrium moisture content (EMC), ambient pressure, vacuum drying, wet-bulb temperature


The equilibrium moisture content (EMC) of Russian larch wood, Sugi wood, and Hinoki wood was measured under vacuum conditions at temperatures of 45, 50, and 60°C and ambient pressures of 13.3, 53.3, and 101.3 kPa. The results show that the EMC of each species increased with a decrease in ambient pressure. The effect of temperature and RH on EMC under vacuum conditions showed a similar tendency. Wet-bulb temperature needed to be controlled to measure EMC, even under vacuum, because pressure was not maintained only by water vapor pressure because of the presence of air in the vessel. There were obvious differences between the EMC values obtained in this experiment and previous experimental EMC values in which the wet-bulb temperature was not controlled.


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