Under the “Good Manufacturing Practices Guidelines, 2009 Edition (GUI-0001)”, there is no limit for the relative humidity % of the air used for pneumatic equipment and to dry manufacturing tanks. From a general perspective, based on Interpretation 4 under Section C.02.004 Premises, the humidity must be controlled where required to safeguard sensitive materials. Consequently, it is the fabricator, packager/labeller’s responsibility to establish the pertinence of such control. If the humidity % of the compressed air used at the last step of drying of a reservoir is too high, micro-droplets of water could be generated on the internal surfaces by condensation, hence contributing to the possibility of microbial growth following storage. Similarly, it is important to make sure that residual water has been completely eliminated from hard to reach surfaces of the equipment after cleaning operations.
