ISO 8573-1:2010 is the international standard for Air Quality Classes. It lays the ground rules for acceptable levels of pollutants, particulate, moisture, and oil in a compressed air source.
Though the standard has detailed standards for maximum particle size, maximum pressure dew point and maximum oil content for different industries and/or environments (see Slide show above) we can generalize a bit and express the levels of air quality like this:
Plant Air – general plant compressed air used for air tools, nozzles etc.
Instrument Air – found in laboratories, paint and powder coat booths, used for climate control.
Process Air – used in food and pharmaceutical applications, electronics applications.
Breathing Air – used for breathing respirators, breathing tanks and hospital air systems.
Achieving the different levels of air quality can be done with 3 basic types of filtration.
1. Particulate – a filter element removes particles larger than the opening in the filter material. Typically done with particles greater than 1 micron.
2. Coalescing – use different methods to capture the particles; 1) direct interception – works like a sieve, 2) Inertial impaction – collision with filter media fibers, 3) Diffusion – particles travel in a spiral motion and are captured in the filter media.
3. Adsorption – the filter element holds the contaminants by molecular adhesion.
The higher the class your air needs to be the more of these filtration methods you will use. Adsorption will remove more and finer particles than a simple particulate filter. And many applications will use a combination of these methods.
EXAIR products, all of which need a source of “clean, dry air” will operate very well utilizing a source of plant air and only a particulate filter. Your process, dictate if you need to supply additional filtration methods for better air quality. For example, an automotive plant using compressed air to blow parts off will not need the kind of filtration a food handling facility will need while blowing a food product off. If you are using a lubricated compressor or have lubricant in your compressed air lines from another source, you will want to use a coalescing oil removal filter.
EXAIR stocks 5 micron particulate filters which are properly sized for each individual product as an option for our customers if they choose. We also stock coalescing oil removal filters for customers who may need to remove oil from the air. Replacement filter elements are also available and should be replaced at least twice a year, depending on the quality of your air.
Remember to ask about filtration if you have any concerns about your air quality. We can assist in sizing up the proper filters to get the air quality we recommend for proper operation and longevity of our products.
If you would like to see how we might be able to improve your process or provide a solution for valuable savings, please contact one of our Application Engineers.
Image Courtesy of the Compressed Air Challenge