Compressed air is understood best by the industrial users who rely on it. In the UK, such companies spend over a billion pounds annually on compressed air. Indeed, electricity consumption in the industrial sector accounts for at least 10% of all business usage.
Different sectors use compressed air. For example, food processing and packaging require it to seal food and beverages for shipment. The pharmaceutical industry uses the cleanest air quality to ensure medicine is correctly formulated and not contaminated. Also, compressed air is widely used within the manufacturing sector for automated production utilising pneumatic controls and equipment.
What often gets overlooked, even by regular users, is the importance of compressed air quality. Contaminated air – because of water, oil, dust, rust, or other particulate matter not being removed at source – reduces the lifespan of equipment, increases servicing costs, lowers production quality, and in certain sectors, such as medical, may pose a danger to health.
Table of Contents
Understanding Compressed Air Quality
Compressed air may appear clean but carries various contaminants that can severely impact operations. Dust, moisture, and oil become highly concentrated in the compressed air stream, amplifying their harmful effects.
Dust and Particulates:
A cubic metre of air can contain millions of particles, which, if left untreated, can clog systems and degrade performance. High-efficiency filters are essential for removing these contaminants from the compressed air, ensuring smooth operations in sectors such as food processing.
Moisture:
When air is compressed, moisture condenses potentially damaging pipes and equipment. Compressed air dryers, such as desiccant dryers, are vital for removing excess water to meet air purity classes and prevent corrosion.
Oil:
Oil contamination from external sources or lubricated compressors poses significant risks in sensitive industries like pharmaceuticals. High-quality compressed air filters help remove oil, ensuring the air meets strict standards, such as Class 0 for medical and food production.
By adhering to air quality requirements and using premium compressed air filters, industries can ensure their air treatment systems maintain the required level of air purity. This protects equipment, safeguards product integrity, and ensures regulatory compliance.
Standards for Compressed Air Quality
International quality standards are critically important for compressed air quality. Depending on each use case, different air quality classifications exist to guide the air compression world. The right air matters.
The International Organisation for Standardisation established the global standard for compressed air. It confirms the correct parameters defining Classes 0 through 6 for the cleanest to the dirtiest compressed air quality.
Separate classifications exist for each ISO air quality purity level. It is also possible to rate quality for each of the three main categories – particulates, water, and oil.
Each classification specifies that:
- The maximum number of allowable particles for solid particulate matter e.g. dirt, is measured by m³.
- Oil (aerosol or vapour) is measured by mg/m³.
- Water is measured using 7 bar to 100 psi dewpoint in both Celsius and Fahrenheit. (Loosely described, less moisture in compressed air requires a lower pressure dewpoint).
None of the ISO 8573-1:2010 standards include either gases or microorganisms. This is important in some industries, such as the healthcare or food & beverage sectors, and in an industrial setting, where certain equipment is gas intolerant.
Class 0, the strictest, is used within industries requiring the cleanest air. There are still a few contaminants, but they are miniscule. The manufacturing of medical equipment is a good example of Class 0.
Class 1 is less strict but still ensures extremely clean compressed air – solid particles are heavily restricted on the particle count per micron measurement range.
In some situations, it is possible to adhere to a standard such as ISO 8573-1:2010 Class 1.4.2. In this example, the organisation’s compressed air qualifies for Class 1 in particulates, Class 4 in water, and Class 2 in oil.
Businesses must establish what their compressed air cleanliness requirements are. Then use the necessary equipment to achieve and maintain it.
The Role of Filters in Maintaining Air Quality
To improve compressed air purity, different air filters separate particulates, oil, and water.
Particulates – Dust and other solid matter, depending on a dry or wet state, are captured using either a dry dust particulate filter (sometimes using pleated media inside) or a wet dust filter. An oil aerosol also works on wet matter. Coalescing filters are excellent for wet matter, allowing droplets to form which are captured by wrapped media inside the filter.
Water – Liquid water does not need a filter per se. Instead, it requires a water separator aftercooler. However, vapour (moisture in the air) requires a refrigerant, desiccant, or membrane dryer to capture the moisture and remove it from the compressed air.
Oil – Oil filters, similar to the case with wet particulates oil filters such as an oil aerosol or a wet dust filter, capture liquid oil successfully. For hydrocarbon vapour, either an oil vapour filter or an activated carbon tower is required. Finer filters, such as micro-structured activated carbon filters, are the latest type. Their larger surface area permits superior absorption rates over regular activated carbon filters.
Different types of filters exist for a good reason. Knowledgeable compressed air users must match the appropriate filter type to the quality level required. No single filter or equipment, such as a dryer or aftercooler, removes all, or even most, potential contaminants. Therefore, a layered approach to produce clean air is necessary.
Additional Air Quality Considerations
Air dryers are integrated into the air compressor or sold as a separate unit.
Integrated dryers save precious space and lower installation expenditures. They are necessary to dry compressed air and remove moisture to acceptable levels based on ISO classification requirements.
There are several types, including:
- Refrigerant dryers
- Non-cycling dryers
- Cycling dryers
- Variable speed drive (VSD) dryers
- Desiccant dryers
- Heatless dryers
- Heated purge regenerated dryers
- Blower regenerated dryers
- Heat of compression dryers
- Membrane dryers
Each dryer type and sub-type have pros and cons. Simpler models are more affordable but generally less energy efficient. Our consultants at J Ll Leach can provide a detailed overview.
For example, refrigerant dryers are the most common and work best below a 50% humidity level. The non-cycling dryer uses a basic design but runs continually, consuming more energy. The VSD dryer, on the other hand, only runs as needed and adjusts its speed based on the air pressure levels and other inputs. It is vastly more energy efficient as a result.
Regular checks and planned maintenance of all filters and dryers ensure optimal performance. Inefficient operations, such as a reduced ability to remove moisture from the air, potentially impact product quality and the longevity of plant equipment.
Real-World Applications
Compressed air is essential across industries, but air quality plays a key role in ensuring safety and efficiency.
Food and Beverage:
Compressed air comes into direct contact with products, making high-quality air crucial in food processing. Contaminants such as oil and moisture can lead to product recalls, so using high-grade compressed air filters ensures air classified as Class 0 meets hygiene standards.
Pharmaceuticals and Medical Devices:
In the pharmaceutical sector, compressed air must be pure to prevent contamination. Air classified as Class 0 ensures the cleanest air possible, and filters designed to remove contaminants help maintain product integrity and safety.
Manufacturing:
Poor air quality can damage machinery, disrupt production, and increase costs. Using the correct air compressor system with appropriate filters helps eliminate contaminants from compressed air, ensuring smooth operations and improved efficiency.
Healthcare:
Hospitals rely on compressed air equipment for medical devices. Air quality is vital in these settings, where clean air can prevent patient complications. Maintaining the highest air quality through air treatment solutions is essential in critical care environments.
Industries can safeguard their operations and meet their specific air quality requirements by using compressed air filtration systems and selecting the right air quality solutions.
Conclusion
Numerous UK business sectors depend on quality air. This can only be achieved with the right equipment and proper installation – inferior air contamination is costly in product manufacturing, operational equipment, and lowered reliability.
We recommend discussing your compressed air requirements with our team at J Ll Leach, contact us today. Our experts can provide a best-in-class compressed air system offering reliability, safer operations, and improved energy efficiency.
FAQ
What types of compressed air filters are best for maintaining air quality?
Compressed air filters are designed to remove various contaminants from the air, including dust, oil, and moisture. Common filter types include particulate filters, which remove solid particles, coalescing filters for oil aerosols, and activated carbon filters for vapours. The right filter depends on your specific air quality requirements and the contaminants present in the compressed air.
Why is air quality important in industries where compressed air is used?
Air quality is vital because contaminants in compressed air can damage equipment, affect product quality, and pose safety risks. For example, in industries such as food processing and pharmaceuticals, where compressed air comes into direct contact with products, maintaining high-quality air is essential to meet safety and regulatory standards.
How do desiccant air dryers help improve compressed air quality?
Desiccant air dryers are used to remove moisture from compressed air, which is crucial for preventing corrosion and damage to equipment. By lowering the dew point of the air, desiccant dryers ensure that compressed air used across various industries remains dry and safe, contributing to the high air quality required for efficient operations.
