· Steam should be absolutely dry for maximum heat content · Wet steam means a mixture of steam with droplets of liquid water · Steam with a dryness fraction of 92% means that out of the total mass of steam, 8% is present in the form of water Wet Steam causes following disadvantages- 1. Water hammer 2. Corrosion and scaling 3. Reduced heat transfer 4. Increased load on steam traps 5. Equipment damage