In many fields, like pharmaceuticals, food processing, and electronics, clean air is not just preferred; it’s a legal requirement. These industries view ISO 8573-1 Class 0 as the top standard for purity.
At National Filters Pty Ltd, we help clients understand that reaching Class 0 doesn’t always need costly oil-free air compressors. Many believe only these compressors can meet high standards, but inline filtration offers a strong, cost-effective way to get “technically oil-free” air that meets ISO 8573-1 Class 0.
Understanding ISO 8573-1 Class 0 Benchmark
ISO 8573-1:2010 sets the global standard for compressed air purity. Class 1 allows up to 0.01 mg/m³ of total oil. Class 0 is even stricter. It demands air that is 100% free of hydrocarbons, oil aerosols, or oil vapors. Even oil-free compressors can introduce oil into the system by drawing in hydrocarbons from the air, which are then condensed and released into air lines.
How Inline Filtration Delivers Oil-Free Air
While ”technically oil-free” air is often associated with oil-free compressors (mainly by the companies selling them), the right combination of high efficiency filters can strip out contaminants to nearly undetectable levels while using standard lubricated air compressors.
The Multi-Stage Filtration Process
Achieving this level of purity requires a multi-stage approach to address different forms of contamination.
1. High-Efficiency Coalescing Filtration
The first line of defence is a coalescing filter. These filters, such as our 0.01 micron elements, are designed to remove bulk liquid and oil mist and aerosols. To protect these sensitive elements, we recommend a 1 micron pre-filter to capture larger particles and water droplets.
2. Oil Vapour Removal with Activated Carbon
Standard coalescing filters cannot remove oil vapour or odour, which can still contaminate sensitive processes. To achieve true Class 0 air, an activated carbon filter or carbon tower must be installed downstream. These use adsorption to reduce oil vapour levels to as low as 0.003mg/m3.
3. Strategic Point-of-Use Installation
For maximum efficiency, filtration should be installed as close to the point of use as possible. This prevents re-contamination from the piping system. In critical environments, using stainless steel piping is also recommended. This avoids particle generation that can occur with other piping materials.
Overcoming Temperature – Related Oil Carryover in Inline Systems
Filtration performance is highly dependent on the air temperature. As compressed air temperature increases, oil carryover also increases. To guarantee Class 0 air, your system must include effective compressed air dryers and/or aftercoolers to keep the air cool and dry before it hits the final stages of filtration.
Why Choose Inline Filtration Over Oil-Free Air Compressors?
- Cost efficiency: Implementing a high grade inline filtration system often requires a lower initial capital investment than a dedicated oil-free air compressor.
- Flexibility: You can upgrade your existing lubricated compressed air system to meet Class 0 standards at specific points of use rather than replacing the entire plant.
- Reliability: With the correct filtration set up, you can gain peace of mind knowing that your air purity is consistent when it’s monitored and maintained.
- Protection: Safeguard your products from spoilage and your equipment from costly downtime.
- Expert Guidance: Our team offers expert advice to tailor a solution to your unique needs.
|
OIL-FREE COMPRESSOR |
FILTRATION SOLUTION |
|
High Initial Investment |
Lower Investment (uses existing assets) |
|
Costly Specialist Maintenance |
Simple, Cost-Effective Maintenance |
|
Fixed Solution Plant Wide |
Flexible, Scalable, Point of Use |
|
Redundancy Requires 2nd Unit |
Easily Parallelised and Replicated |
Cost of ownership between a new oil-free compressor and an inline filtration upgrade
Why Choose National Filters?
As an Australian owned wholesaler,National Filters Pty Ltd provides expert guidance and local support to protect your critical processes. We are specialists in compressed air treatment. We provide a comprehensive range of compressed air treatment products from Europe to ensure your system remains compliant with the highest industry standards.
Ready To Upgrade Your Air Quality?
Don’t leave your product quality to chance. Contact the experts at National Filters today to discuss your filtration requirements and ensure your facility meets Class 0 standards.

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