As Part of PAS 223 (Prerequisite Programs for Food Packaging) it states that the organization shall establish requirements for air used as well as compressed air & gases. In a nutshell, our current procedure states that HVAC & Compressed air systems must be maintained according to the supplier or manufacturer. Oils, Lubricants, and filtration must be made of acceptable food grade materials.Evaluations on fans & other blowing equipment is done to ensure that it doesn't compromise product safety. Are we doing enough or do I need to have environmental testing conducted on these systems. It's easy for me to say that we're providing adequate ventilation, but how do I justify that beyond what our current procedure states?