If your compressed air system runs Atlas Copco dryers and compressors, chances are you're already familiar with the DD, PD, and QD filter series. These housings are installed in tens of thousands of industrial facilities across Europe — and when service time comes around, many maintenance engineers assume they must buy original Atlas Copco replacement elements. That assumption costs money. R+F FilterElements offers fully compatible replacement elements for the entire DD, PD, and QD range, cross-referenced by housing dimensions and performance class.
Understanding the Atlas Copco DD, PD, and QD Filter Series
Atlas Copco's compressed air filtration line covers three primary filter types, each targeting a different contamination class under ISO 8573-1:
- DD series — Coalescing filters for bulk liquid water and oil aerosol removal. Typically installed as the first stage after the aftercooler.
- PD series — High-efficiency coalescing filters for fine oil aerosol and particulate removal. Second-stage filtration achieving ISO 8573-1 Class 1 oil content.
- QD series — Activated carbon adsorption filters for residual oil vapour removal, achieving oil vapour concentrations below 0.003 mg/m³.
These housings are robust and long-lived. The elements inside them, however, are consumables — and that's where the real cost lies over the lifetime of the system.
Why Engineers Switch to Compatible Replacement Elements
The economics are straightforward. OEM replacement elements for Atlas Copco DD, PD, and QD filters carry a significant brand premium — often 40–70% above the cost of a dimensionally equivalent, performance-matched alternative. For a facility running a dozen filter housings on annual service intervals, that premium adds up to thousands of euros per year.
Beyond cost, there are practical reasons to consider alternatives:
- Lead time flexibility — OEM elements are sometimes on extended lead times, particularly for older housing sizes. Compatible elements from stock can prevent unplanned downtime.
- Consolidation — If your site runs multiple compressor brands, sourcing all replacement elements from a single specialist simplifies procurement and reduces the number of supplier relationships to manage.
- Performance transparency — R+F elements are tested and rated to ISO 8573-1 classes, with published efficiency data. You know exactly what you're getting.
R+F Replacement Elements: Performance at a Glance
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Cross-Reference: Atlas Copco DD/PD/QD to R+F Elements
The table below maps common Atlas Copco filter series to the corresponding R+F replacement element by type and size code. Dimensions are the primary matching criterion — always confirm against your housing nameplate before ordering.
| Atlas Copco Series | Filter Type | ISO 8573-1 Class | R+F Replacement Element | Notes |
|---|---|---|---|---|
| DD (bulk coalescing) | Coalescing | Class 2–3 oil | RF-C (coalescing) | Match by OD × length; borosilicate microfibre |
| PD (high-efficiency coalescing) | Coalescing | Class 1 oil | RF-C (coalescing) | 99.99% @ ≥ 0.1 µm; confirm end-cap style |
| QD (activated carbon adsorber) | Adsorption | Class 1 oil vapour | RF-AC (activated carbon) | Residual oil < 0.003 mg/m³; granular activated carbon |
| DD/PD (particulate duty) | Particulate | Class 1–2 solid | RF-P (particulate) | 99.99% @ ≥ 0.3 µm; dry-duty applications |
Use our free Engineering Tool to get a filtration recommendation for your specific application in under 2 minutes.
Selecting the Right R+F Element for Your Atlas Copco Housing
The R+F compressed air filter range covers elements in six standard size codes — 12032, 12057, 25064, 25178, 51230, and 51476 — which correspond to the most common internal dimensions found in Atlas Copco DD, PD, and QD housings from the G-series through to the larger industrial frames.
To identify the correct replacement:
- Note the housing model number from the nameplate (e.g. DD 145+, PD 145+, QD 145+).
- Record the element outer diameter and length from the existing element or housing documentation.
- Match to the R+F size code using the cross-reference above or the R+F Engineering Sizing Tool.
- Confirm the end-cap configuration (flat gasket, threaded stud, or bayonet lock).
For the DD and PD series, the RF-C coalescing element is the standard replacement. For QD adsorber housings, the RF-AC activated carbon element provides equivalent oil vapour removal performance. Where a particulate-only duty is required — for example, downstream of a refrigeration dryer — the RF-P particulate element is the appropriate choice.
If you're unsure which element applies to your specific housing variant, the R+F FilterElements engineering team can confirm the correct cross-reference from the housing model number alone.
Service Intervals and Differential Pressure Monitoring
Atlas Copco recommends annual element replacement for DD, PD, and QD filters under normal operating conditions, or earlier if the differential pressure indicator shows red. R+F replacement elements are designed to the same service life expectation. However, in applications with high inlet contamination — for example, older reciprocating compressors or systems without adequate pre-filtration — more frequent replacement may be warranted.
A useful rule of thumb: if the differential pressure across a coalescing element exceeds 0.35 bar at rated flow, the element is approaching end of life regardless of elapsed time. Continuing to run a saturated element increases pressure drop, raises energy consumption, and risks downstream contamination if the element structure fails.
For a broader look at how coalescing and particulate elements compare in compressed air duty, see our guide on coalescing vs particulate filter elements.
- Atlas Copco's compressed air filtration line covers three primary filter types, each targeting a different contamination class under ISO 8573-1:
- Lead time flexibility
- The table below maps common Atlas Copco filter series to the corresponding R+F replacement element by type and size code.
- The R+F compressed air filter range covers elements in six standard size codes — 12032, 12057, 25064, 25178, 51230, and 51476 — which correspond to the most common internal dimensions found in Atlas Copco DD, PD, and QD housings from the G-series through to the larger industrial frames.
Compressed Air Quality Standards and Compliance
Whether you use OEM or compatible replacement elements, the compressed air quality standard that governs your system remains the same: ISO 8573-1. This standard defines purity classes for solid particles, water, and oil content. R+F elements are rated and tested to ISO 8573-1 classes, so you can document compliance with the same rigour as OEM elements.
For food and beverage, pharmaceutical, or electronics applications where Class 1 oil content is mandatory, the RF-C coalescing element followed by an RF-AC adsorber provides a two-stage train that meets the most stringent requirements — equivalent to the Atlas Copco PD + QD combination.
Related Reading
- Coalescing vs Particulate Filter Elements — Which Do You Need?
- ISO 8573-1 Compressed Air Quality Classes Explained
- Oxygen Filtration Safety — What Every Engineer Should Know
Try our Engineering Sizing Tool → or discuss your requirements with our team.
