Air venting is the small amounts of air which are left over after the air is drawn once the steam supply is shut off. This results from the residual steam which condensates after which it enters the feed water with the air particles. The air portion are non condensateable and accumulates over the steam lines which takes up space over time and disrupt the steam flow overtime. Even inadequate water treatment leads to high CO2 in the water which accumulates in the steam lines.

                                             Automatic air vents should be provisional above the ends of the steam main so that these gases maybe discharged. Air venting is a critical and mostly neglected area of steam transfer lines.