We had a regular GMP inspection last week.... two Health Ministry guys spend a day auditing our factory. We are not doing anything too special....cold process soap, liquid soaps via saponified oils, face oils etc., and very soon a hair conditioner.
Issue that came up was Relative Humidity (RH). In a number of rooms we have Hygrothermometers and record max/min temperature and RH daily. This includes the ingreredient storage, and finished products storage rooms. Allowable min/max temperatures are stated. Their issue was that (1) we have not stated min/max RH, and (2) these Hygrothermometers need to be calibrated by a licenced company on an annual basis.
My argument was that absolutely non of our ingredients has stated RH storage conditions on labelling and CoAs. Therefore, what min/max RH do we stipulate? There are max/min temperature requirements for ingredients, but not finished products, and these ranges are very wide. Putting these two together, I questioned the need to have these Hygrothermometers officicially calibrated.
Would be interested in opinions here from others with GMP rated factories.