Compressed air is often a critical tool in aseptic pharmaceutical manufacturing processes, particularly in environments where it comes into close contact with the final product. To ensure product integrity, it is critical to control the cleanliness of compressed gas systems. This article describes essential guidelines for maintaining compressed gas purity and quality, with a focus on contaminants, monitoring, and preventative maintenance.
Compressed gas contamination sources
Before setting up a compressed air system, it is important to consider the materials used in construction, the function of the subsystems, and the design parameters. Identifying potential contaminants is key to determining the cleanliness level of compressed air. The main air quality risks in compressed gas systems include:
- particles
- Water
- Total oil
These pollutants must be kept within legal limits. For example, the FDA requires that the purity of compressed gas must meet or exceed the purity of the environment, while the EU GMP Annex 1 requires certain quality parameters.
System design and purity assurance
During the qualification phase of a compressed air system, the installation quality must be confirmed. Limit values are set for particle number, microbial concentration, moisture and total oil. Properly located and accessible sampling points are essential for ongoing quality control. These points should be strategically identified through a risk analysis to prevent cross-contamination.
Frequency of monitoring compressed gas contamination
Routine monitoring of compressed air systems is critical. The frequency of monitoring should be determined based on a risk analysis to ensure that contaminants are detected before they affect product quality. Regular checks and trend analysis can help adjust monitoring frequency over time.
Compressed gas sampling methods
According to ISO 8573, there are various full-flow or partial-flow (isokinetic) sampling methods for measuring pollutants.
All equipment used for sampling must be clean and made of appropriate materials such as stainless steel to avoid introducing new contaminants.
Microbial contamination
Although rare, microbial contamination can occur in compressed gas systems. Regular microbiological sampling helps to identify and contain potential sources of contamination.
How particle measurement systems can help
At Particle Measurement Systems (PMS), we offer comprehensive support throughout the entire lifecycle of compressed gas systems, from installation to monitoring. Our services include:
- System qualification: Checking cleanliness and freedom from contamination.
- Risk analysis: Identify potential contaminants and create monitoring plans.
- Sampling equipment: Use of tools such as the MiniCapt® Mobile Air Sampler and the HPD™ High Pressure Diffuser for effective contamination control. The MiniCapt® mobile air sampler enables usable microbiological measurements while the HPD™ offers a straightforward solution to particle contamination control.
Would you like to read more? Jump to other published posts in this series:
The importance of risk assessment of compressed gases in pharmaceutical manufacturing
or
Read the article “Compressed Gas Risk Assessment: A Significant Step in Your CCS.”