This experimental study of the flash evaporation phenomenon of a water film was carried out with an initial water height of 15 mm, superheats ranging from I to 35 K and initial temperatures from 30 to 75 degreesC. During a sudden pressure drop, temperature measurements of the water film allowed us to determine the water mass evaporated by this phenomenon as well as the mass flow rates. A correlation between the water mass evaporated by flashing and the superheat was then obtained. Evolution of the flash evaporation rate coefficient let us estimate the duration of the flash evaporation phenomenon.