How to Select the Correct Grade Filter Element for Your Compressed Air Systems

When designing or maintaining a compressed air system, choosing the right filter element is crucial to ensure the air quality meets your application's needs. Different grades of filter elements are engineered to handle varying levels of contaminants, from water and oil aerosols to vapours and fine particles. Here's a breakdown of the most common filter grades and how to choose the right one.

Grade P – Prefilter Coalescer (5 Micron, 98% Efficiency)

Best for: Dirty environments with high liquid and particle contamination.

Grade P elements are designed to remove coarse particulates and large volumes of condensate. With a 98% efficiency against 5 micron particles, they are ideal for portable compressors, sandblasting sites, and other rugged applications where high dirt holding capacity is essential.

Airflow direction: Inside to outside
Function: Coalesced water and oil drain into the bowl, while particulates are captured in the filter media. Clean air exits through the outlet port.

Grade X – General Purpose Coalescer (1 Micron, 99.25% Efficiency)

Best for: Day-to-day protection of pneumatic components.

Grade X filters offer 99.25% efficiency against 1 micron particles and aerosols, making them suitable for most general-purpose applications. They're commonly used to protect valves, cylinders, air tools, motors, and pumps from damage caused by oil and water contamination.

Airflow direction: Inside to outside
Function: Traps fine particles and coalesces aerosols into the bowl for draining.

Grade Y – Submicron Coalescer (99.99% Efficiency)

Best for: Critical processes demanding ultra-clean air.

Grade Y filters provide 99.99% efficiency against ultrafine particles and aerosols. They're essential for sensitive applications such as air bearings, spray painting, instrumentation, laser systems, and any system involving direct or indirect food contact.

Tip: For optimal performance, always install a Grade X as a pre-filter before Grade Y.

Airflow direction: Inside to outside
Function: Ensures the highest level of particulate and aerosol removal.

Grade A – Odour & Vapour Adsorption (Activated Carbon)

Best for: Removing odours, taste, and hydrocarbon vapours.

Grade A elements are filled with highly concentrated, activated carbon media and designed to adsorb vapours not captured by coalescing filters. These are essential in applications where smell or vapour residue must be eliminated, such as in food packaging or precision electronics.

Airflow direction: Outside to inside
Function: Activated carbon traps vapours, delivering purified air through the centre outlet.

Choosing the right filter element grade isn't just about clean air — it's about protecting your equipment, improving performance, and ensuring compliance in critical applications. Start with your end-use in mind and build your filtration stages accordingly: from coarse protection (Grade P) to fine purification (Grade Y) and vapour removal (Grade A).

Need help selecting the right filter for your system? Our team can guide you through it — just get in touch.