SATURATION

Temperature and pressure at which water can exist in equilibrium as gas and liquid, or as gas and solid. The amount of water vapor in a volume of space when in equilibrium with the liquid phase at a given temperature. When the relative humidity is 100 percent, the air has reached saturation. The vapor pressure in the air is in equilibrium with the vapor pressure over a plane surface of pure water so that the rate of evaporation and condensation are equal.