- Compressed air is inherently dirty, containing contaminants from ambient air and the compression process itself, such as water, oil, and particulates. Whereas at the end use applications, the contamination in compressed air could contain water vapour, condensed liquid water, water aerosol, atmospheric particles, micro-organisms, oil vapour, liquid oil, oil aerosol, hydrocarbons, rust, pipe scale, etc…
- Particles: These are solid impurities that may include dust, rust, or dirt that enters the system through intake or internal erosion of system components. Particles can cause abrasion and wear of pneumatic machinery, leading to frequent maintenance needs and potential downtime.
- Water: Moisture is a common contaminant in compressed air systems. It can originate from the humidity in ambient air or from the compression process itself. Excess water can lead to corrosion of metal parts and piping, resulting in leaks and pressure drops. It also poses a risk for microbial growth, which could compromise product purity in sensitive industries like food processing or pharmaceuticals.
- Oil: Oil in compressed air typically comes from lubricated compressors and can be problematic, particularly in applications that demand oil-free air such as painting or food production. Oil vapours and aerosols can contaminate end products and lead to the failure of pneumatic controls and valves.
- Hydrocarbons: The compressor intake pulls air from the environment (ambient air) into compressor, including the vapours from nearby cleaning establishments, chemical plants, manufacturing plants, or even motor exhaust from idling or passing vehicles. Because compressor’s filters are not designed to remove hydrocarbons, contaminants present in ambient air may end up in the discharge of the compressor. There are as many sources for hydrocarbon contamination in the environment as there are varieties and uses for hydrocarbons.
There are some other types of contaminants, like micro-organisms, (harmful) gases and odours, but for industrial applications those are of lesser concern
The presence of these contaminants in compressed air systems not only compromises product quality but also leads to operational inefficiencies. Unchecked, they can incur high maintenance and operational costs due to:
- Dirt, water and rust get stuck inside pneumatic equipment. Valves get stuck or wear down, same for cylinders and air tools. Increased wear and tear on equipment, necessitating repairs and replacements.
- Spoiled or contaminated products resulting in direct losses and potential damage to brand reputation (e.g. damaged paintwork).
- Energy inefficiencies as compressors work harder to maintain required pressures, raising utility costs.
High quality compressed air does not cause rust and dirt in compressed air piping system, thereby reduces maintenance and breakdowns on air tools like Grinders and Nailers and reduce wear and tear on machines with air cylinders and moving parts.
Air quality standards – the guidelines that ensure compressed air is suitable for specific uses are very important in the compressed air industry. The most notable of these standards is ISO 8573-1, which benchmarks the level of purity required in various industrial processes.
ISO 8573-1:2010 is the primary standard for compressed air quality. It outlines precise classifications for air purity, it specifically outlines specific requirements for compressed air purity, quantifying the acceptable amounts of particles, water, and oil in compressed air.
This detailed classification helps industries determine the level of filtration needed to ensure their air quality meets the necessary criteria for their specific applications.
By categorizing air purity into different classes, ISO 8573-1:2010 allows manufacturers and other users to align their systems with clear, international benchmarks.
ISO 8573-1:2010 Compressed Air Contaminations and Purity Classes
As mentioned in the above chart, Class Zero is specified as only to be ‘more stringent’ than class 1. In practice, it is not possible to measure Class 0 (Zero) parameters as per ISO 8573-1:2010.