Library humidity and mould growth · Physics Brawl 2014 #FoL.6
Physics · thermodynamics
Problem
In order to protect books from becoming damp, some libraries choose to keep the relative humidity at ϕ0=25%. Find the mass of water which would (after complete evaporation) turn such a library into a suitable environment for mould growth. You can assume that the ideal value of relative humidity for mould growth is ϕp=60%. The total volume of air in this particular library is V=180 m³, the (constant) ambient temperature is t=24°C and the saturated vapour density at 24°C is 21.8 g·m−3.