Drying is the process of removing excess moisture from materials and involves the sciences of psychometry and drying principles.
- Enhancing Evaporation;
- Once bulk water has been removed evaporating the remaining water in materials should be promoted. Evaporation is the process of changing a liquid to a vapour. It is enhanced by adding energy and air movement to the surface of wet materials.
- Enhancing Moisture Diffusion;
- Excess moisture in affected materials moves as a liquid and as a vapour toward the surface, where it can evaporate. the rate of this movement is a function of water vapour pressure, moisture content, and physical properties (i.e. porosity, permeability) of the material. It is enhanced by managing the surrounding humidity, air movement, and by introducing energy (i.e. heat) into the materials.
- Dehumidifying and ventilating;
- As moisture evaporates from structural materials and contents, the indoor relative humidity, humidity ratio, and water vapour pressure will increase if not controlled. Abnormally high water vapour pressure can drive elevated moisture into materials, increasing the potential for secondary damage (e.g. microbial growth, discolouration, adhesive release, delamination, swelling, buckling, and warping). Therefore, in order to avoid secondary damage, excess moisture evaporating into the air should be exchanged with less humid air or it should be removed from the air through dehumidification. Failure to remove evaporation moisture can retard the drying process.
- Controlling Temperature;
- Specialised Restoration Services (SRS) will control temperature in the drying environment. Reasons include but are not limited to affect evaporation load and moisture movement in materials, avoid secondary damage, limit microbial amplification and maximise equipment performance.