The instrument air shall be dust-free, oil-free and dry.
To prevent condensation in the supply piping or in the instruments, the dew point of the air at operating pressure after drier shall always be at least 10oC lower than the lowest ambient temperature ever recorded in the area.
Under normal operation the instrument air shall have a pressure of at least 8 barg in the buffer vessel, and a pressure of 7 barg in the supply piping.
The required quantity of instrument air shall be estimated as accurately as possible, taking into account the requirements for: