Ontario Environmental & Safety Network Ltd.
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Does your compressed air require testing?

​Compressed air quality is a critical factor in food manufacturing.  The Canadian Food Safety Enhancement program has identified compressed air and gas used in processing and packaging as a potential source of contamination. Compressed air must be contaminant-free to ensure the protection of the food products processed in each facility. Compressed air quality is often overlooked as a potential hazard during internal risk assessments.  This is likely because compressed air is odourless, colourless and tasteless or because many people consider compressed air to be – just air. Contaminated compressed air can create major issues for a food manufacturer.

Compressed air contamination sources include the ambient intake air and the compressor itself.  At any given, time the atmospheric air feeding the compressor inlet can have contaminants such as solid particles, water vapour, oil vapour and micro-organisms.  Careful consideration should be given to the placement of the compressor intake to avoid these contaminants as much as possible. 

The presence of moisture is the primary concern for the food industry because moisture creates an ideal breeding ground for mould growth. Microorganisms and fungi can grow inside the piping system and then be blown into food products or food containers. In order to inhibit the growth of microorganisms and fungi, pressure dewpoints must be below -15˚F (-26˚C). Drying the compressed air to a specified pressure dewpoint is the simplest way to eliminate moisture in a compressed air system. Oil aerosols and vapours are other contaminants of compressed air.  Having an oil free compressor does not exempt the system of any ​compressed air treatment/testing requirements.  Compressed air dryers and filters are always required.

A compressed air testing program can provide critical information to monitor air quality and help prevent contamination of the food supply. Qualified personnel should be employed to properly maintain service and test the compressed air system. Compressed air is used in many segments of the food industry. Bakeries for example, use it to clean containers before filling with food.  Compressed air is also used to cut, sort and shape food products, as It can be used in a range of pressures from high to low depending on the application. 

International Standards Organization (ISO) has established a specification that targets compressed air - ISO 8573.  ISO 8573 is comprised of nine documents that describe compressed air contaminants and purity classes, plus the sampling and analytical techniques to be used.  The performance of a compressed air system may be evaluated in terms of compressor output at the compressor itself, in the piping downstream of the compressor and at the various points of use.  Knowledge of the compressor output is important in terms of selecting downstream filtration and assessing gross contamination of the piping system. 

Partial flow sampling is inappropriate in systems where steady-state flow, temperature and   pressure cannot be maintained. ​ Full flow sampling may be used at any point, requiring a sampling device that has the capacity to handle the full flow at that point in the system.  This accounts for the vast majority of samples, as most users wish to know the air purity at the point of use where air may come in direct or indirect contact with the product. Compressed air efficiently supports the food industry, so long as due diligence is taken to remove contaminants from the system and regular compressed ​ air testing is undertaken. 

ISO 8573 Air Testing

ISO 8573 is a standard that is made of purity classes for contaminants in compressed air that can be used to describe the quality of a compressed air system and to specify the required quality for a precise application. The three contaminants are particles, water and oil.  The ISO standard also identifies microbiological contaminants. The compressed air used in manufacturing processes should be tested by a competent technical individual to determine the appropriate requirements to protect the integrity of the products. ISO compressed air testing highly recommends routing regular testing of your compressed air systems  to meet your air quality program and for verification and compliance with any standards your organization is seeking. 

Clean, dry air is necessary for many different compressed air applications.  Air compressors draw in large volumes of air from the surrounding area.  The compressors themselves can add contaminants to the compressed air.

Oil and Particulate

Most air compressors use oil in the compression stage for sealing, lubrication and cooling.  The oil used for these purposes can easily be carried over to the compressed air system. Oil is able to mix with the water vapour in the air which may cause damage to the compressed air system. Particles in your compressed air system is also problematic, as they will plug orifices of sensitive pneumatic instrumentation, wear off seals, erode components and reduce efficiency. 

Condensed Water / Dewpoint

A lower dew point temperature means the air is drier than if there was a higher dew point temperature.  Condensed water can increase maintenance costs or cause corrosion and rust to your system and piping. Some compressed air systems may malfunction if condensation forms on internal parts.  Water vapour can cause damage to labeling, packaging and finished goods.