Compressed air for pharmaceutical use is considered a critical utility as many of its applications involve direct contact with the pharmaceutical product. For example, compressed air is frequently used to over - pressurize mixing and holding tanks and to pressurize liquid product through filters and fill lines. Finally, automated production lines use compressed air to operate control valves and pneumatic cylinders. Exhaust air from these components could contaminate the local environment and consequently the end product.
Therefore, the compressed air system must be properly designed and built from the outset. The subsequent initial validation testing and the ongoing monitoring of compressed air is vital to assuring both the quality and safety of the pharmaceutical product. Compressed air is often overlooked as a potential source of clean room and product contamination.
A pharma quality compressed air system typically consists of -
- a compressor and after-cooler,
- air receiver storage tank,
- particulate filter(s),
- coalescing filter(s),
- a desiccant air dryer(s),
- a pipeline distribution system, and
- various point-of-use filters including sterilizing filters for aseptic operations.
The compressor is typically an on-demand, oil-free type. Compressed air discharged from the compressor is hot and loaded with water vapor. The compressed air enters an after-cooler unit which cools the air resulting in condensation of air moisture and hydrocarbon vapors which are then drained through automated drain valves.
It is recommended that the compressed air is treated for major contaminant reduction to a “general purpose” quality level prior to entry into the distribution system.
The quality standards for a pharmaceutical facility are best defined as a composite set of specifications that are site-specific based upon the point-of-use requirements. FDA / EU GMP Guidances, USP/EP and ISO 8573 air standards are common sources from which to draw input as to these specifications.
ISO 8573-1:2010 is an important international standard that provides specifications for a variety of compressed air purity classes. ISO 8573-1:2010 recognizes three classifications of contamination in compressed air. These are:
- solid particulate
- water content
- total oil content (in aerosol,vapor and liquid forms)
FDA Air Classification Guidance: Particulate Air Action Levels
- Class 100 (ISO 5) Environments: 3520 particles / m3 GE 0.5uM
- Class 1000 (ISO 6) Environments: 35,200 particles / m3 GE 0.5 uM
- Class 10,000 (ISO 7) Environments: 352,000 particles / m3 GE 0.5 uM
- Class 100,000 (ISO 8) Environments: 3,520,000 particles / m3 GE 0.5 uM
