Residual oil content in the compressed air

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Measure oil content and pressure dew point - prevent contamination and contamination / ensure hygiene

The monitoring of process gases (utillitis) in the pharmaceutical industry has become a very important aspect of hygiene, inspected by GMP inspectors more and more often. Probably to be able to provide the appropriate documentation on the uninterrupted purity according to GMP.


The audibility of purity in the self-generation of process gases in the pharmaceutical industry has been an issue for many years. Since the free suction of the compressors for compressed air production, an undefined cocktail of pollutants is compressed to a multiple of concentration, the treatment plants must be identified and monitored as a risk element in the system. Since a wide variety of operating conditions prevail and a failure of the treatment (filter / adsorption) can not be excluded. The sequence of an unsupervised process is the product destruction and a contaminated pipeline system. The Compulsory Fundamentals of GMP exist since 2007.

Compressed air is a Critical Process Parameter (CPP) whose variability has an impact on the Critical Quality Attribute (CQA) and therefore needs to be monitored and controlled to ensure that the process produces the desired quality under all operating conditions. [I Q8 (R2) II 4.0]

During commercial drug manufacturing, well-defined process performance and product quality monitoring are required to ensure performance within a production cycle with control and to identify opportunities for improvement. [I Q10 3.2.1] quality risk management must have facilities, equipment and tools. [I Q9] include.

Unlike the food industry, the pharmaceutical industry has a clear commitment to self-monitoring, the basis of which is already laid by the IQ OQ PQ. There, the limits to be met are clearly defined, described and tested for stability. The individual manufacturer is responsible for assessing the risks and impacts that contaminated air could have on the final product. An important international standard, ISO 8573-1, offers a variety of purity classes that can be incorporated into a robust quality assurance plan for this critical program. Testing and monitoring compressed air and other process gases such as nitrogen, oxygen, argon, and carbon dioxide in direct contact with the product is critical to ensuring the quality and safety of the product.

Main sources of contamination in a compressed air supply include the ambient intake air, and the compressor itself (whether oil-free or oil-lubricated).

At any given time, the atmospheric air is supplied to the compressor inlet and thus also impurities such as solid particles (dirt, sand, soot, metal oxides, salt crystals), water vapor, oil vapors and microorganisms (visible and invisible). Careful attention should be paid to the placement of the compressor inlet duct to minimize contamination. The priming filter as the first line of defense should routinely be replaced according to the manufacturer's guidelines. The routine inspections of the downstream treatment components such as filtration and adsorption systems should be complied with and documented.

The compressor, when lubricated with oil, releases oil in the form of liquid, aerosol or vapor. But even oil-free compressors concentrate oily hydrocarbons from the environment. Any improperly maintained compressor can be a source of contamination and seriously impacts the downstream components.
Other sources of pollution may be the piping system and compressed air storage. The compressed air deposits the dropouts there, which then concentrate and become visibly stressful for the production. Clean rooms can be contaminated by the free flow of compressed air into the room. The outgoing compressed air basically has to fulfill the clean room classification.

New piping should be cleaned and tested to ensure that it has been properly freed from potential contaminants such as particulate matter and solder or adhesives used during installation, and that they are unloaded. Older pipelines may have a build-up of water, rust and oil. When connecting a new pipeline, to older pipelines or distribution systems, the vibrations of old pipelines can cause heavy particle loads (such as rust, pipe scale, dirt, metal oxides, etc.) which then migrate into the new pipeline.

Compressed air containers with excess water (steam, liquid or a mixture of oil and water) can be a breeding ground for microorganisms.

Possible problems with compressed air quality can be caused by misuse, improper handling, neglected maintenance and human errors.

  • If you have opted for a sampling plan, several measurement points must be set in the piping and min. be measured for a year. The number of sampling points and the frequency of measurements must then be sufficient to provide sufficient statistical certainty of quality. [CGMP Guidance for Industry Process Validation :. General principles and practices]
  • The permanent monitoring with the OilDewControl provides directly important information about the air quality. The results are immediately visible and recordable.
  • OilDewControl helps prevent contamination of the product and saves money.