ULPA Filters for Ultra-Clean Air Applications

Clean-Link supplies ULPA filters for cleanrooms, semiconductor manufacturing, pharmaceutical facilities, biotechnology, electronics, FFUs, laminar-flow systems, terminal housings, and other critical environments requiring extremely high particulate filtration efficiency.

ULPA filter selection should consider more than efficiency class. U15, U16 and U17 filters differ in required MPPS performance, while media type, pleat geometry, airflow, pressure drop, filter depth, frame construction, sealing method, and testing requirements also affect real system performance.

Clean-Link can support mini-pleat ULPA filters, custom dimensions, aluminum frames, gasket and gel-seal configurations, airflow and pressure-drop review, FFU integration, drawing-based manufacturing, and project-specific testing requirements.

Need a ULPA filter for a cleanroom or FFU project?
Start with Class + Size + Airflow + Pressure Drop + Seal Type + Application.

What Is a ULPA Filter?

ULPA stands for Ultra-Low Penetration Air filter.

ULPA filters are high-efficiency particulate filters designed for applications requiring filtration performance beyond conventional HEPA levels.

Under EN 1822 classification, ULPA classes include:

Camfil and AAF both publish these U15/U16/U17 efficiency levels in their ULPA technical literature.

ULPA classification is based on performance at the Most Penetrating Particle Size (MPPS) rather than a single generic particle-size claim.

What Does MPPS Mean?

MPPS stands for Most Penetrating Particle Size.

It is the particle-size range at which a particular filter has its lowest collection efficiency under the test conditions.

That matters because filter efficiency changes with particle size.

Instead of asking only:

“What percentage does this filter remove?”

a better technical question is:

At what particle size was the filter tested, under which standard, and at what airflow?

EN 1822 and ISO 29463 use MPPS-based methods for high-efficiency filters, which is one reason U15/U16/U17 classifications should not be compared casually with MERV or ISO 16890 ratings.

U15, U16 and U17 ULPA Filters

U15 ULPA Filters

U15 is commonly specified in advanced cleanroom and process environments requiring filtration beyond H14.

Typical applications can include:

• Cleanroom terminal filtration
• Semiconductor manufacturing
• Pharmaceutical cleanrooms
• Electronics production
• FFUs
• Laminar-flow systems
• Precision manufacturing

Freudenberg currently offers U15 ULPA filters with aluminum frames, gasket or silgel seals, and publishes airflow and initial pressure-drop data for multiple sizes.

U16 ULPA Filters

U16 provides a higher MPPS efficiency requirement than U15 and may be selected for more demanding contamination-control applications.

Typical use cases may include:

• Advanced semiconductor fabs
• Critical process tools
• High-grade cleanrooms
• FFU ceiling systems
• Electronics manufacturing
• Specialized research environments

AAF publishes U16 ePTFE ULPA filters for semiconductor-related cleanroom applications, with performance specified at MPPS and pressure drop evaluated under defined face velocity.

U17 ULPA Filters

U17 represents an even higher ULPA classification level.

It may be specified where exceptionally low particle penetration is required.

U17 should not be selected automatically simply because it offers the highest class.

Higher classification should be reviewed together with:

• Required airflow
• Pressure drop
• FFU fan capability
• Filter media
• Media area
• Cleanroom design
• Test method
• Replacement strategy

AAF publishes U15, U16 and U17 ePTFE ULPA filter options in its technical specifications.

ULPA vs HEPA Filters

ULPA and HEPA filters are both high-efficiency filtration technologies, but ULPA classes operate at a higher MPPS efficiency level.

The correct filter is not automatically the one with the highest class.

A U17 filter may be unnecessary where U15 or H14 already satisfies the project specification.

Related article:

HEPA vs ULPA Filters →

Pressure Drop Matters in ULPA Filtration

ULPA filtration requires extremely high particle collection efficiency, but efficiency should never be considered separately from airflow resistance.

Pressure drop is affected by:

• Media type
• Media area
• Pleat spacing
• Pleat depth
• Efficiency class
• Filter size
• Face velocity
• Rated airflow
• Dust loading

AAF's U15/U16/U17 ePTFE literature shows different initial resistance levels by class under the same face-velocity basis, illustrating why pressure drop must be considered together with ULPA efficiency.

For FFU and recirculation systems, filter resistance directly affects the fan operating point and energy demand.

The best ULPA filter is not simply the highest-efficiency filter—it is the filter that meets the required cleanliness level while operating within the system's airflow and pressure capability.

 

ULPA Filter Media Options

ULPA filters can use different high-efficiency media technologies depending on application and project requirements.

Common options can include:

• Microfine glass fiber media
• ePTFE membrane media
• Membrane-composite media

Camfil offers glass-fiber, membrane and composite media options in cleanroom panel filters, while AAF uses ePTFE technology in selected U15/U16/U17 ULPA products.

Media selection may affect:

• Pressure drop
• Mechanical durability
• Chemical compatibility
• Outgassing
• Testing method
• Application suitability

For semiconductor projects, low-outgassing or process-specific media considerations may also matter. Camfil explicitly promotes low-outgassing HEPA/ULPA solutions for semiconductor manufacturing.

 

Mini-Pleat ULPA Filters

Many ULPA filters use mini-pleat construction.

Mini-pleat design allows a large amount of filter media to be installed within a relatively shallow filter depth.

This can help balance:

• High ULPA efficiency
• Media area
• Airflow
• Pressure drop
• Installation depth
• FFU compatibility

But mini-pleat does not automatically mean low resistance.

Actual pressure drop depends on the complete filter design.

 

ULPA Filters for Cleanrooms

Cleanrooms are one of the primary applications for ULPA filtration.

Depending on the project, ULPA filters may be installed in:

• FFUs
• Ceiling terminal systems
• Recirculation air units
• Laminar-flow benches
• Process tools
• Mini-environments
• Cleanroom supply modules

Camfil's cleanroom panel range explicitly targets semiconductor, pharmaceutical and clean-process applications, while AAF offers ULPA modules for semiconductor fabrication, pharmaceutical production, biotechnology and other cleanroom systems.

ULPA selection should be based on:

• Required cleanroom classification
• Particle-control objective
• Airflow strategy
• Ceiling coverage
• Filter class
• Face velocity
• Pressure drop
• Seal design
• Testing requirements

 

ULPA Filters for Semiconductor Manufacturing

Semiconductor manufacturing is one of the strongest commercial applications for ULPA filters.

As device geometries become smaller, microcontamination control becomes increasingly important.

ULPA filters may be used in:

• Fab cleanrooms
• FFU ceiling systems
• Process tools
• Mini-environments
• Lithography areas
• Inspection tools
• Recirculation air systems

Camfil specifically emphasizes particulate and molecular contamination control in semiconductor fabs, while AAF publishes U15/U16/U17 ePTFE solutions for wafer-production environments.

For semiconductor applications, filter review may also consider:

• Low outgassing
• Boron-free requirements
• Chemical compatibility
• AMC strategy
• FFU energy performance
• Filter durability
• Clean packaging
• Individual testing

 

ULPA Filters for Pharmaceutical Cleanrooms

Pharmaceutical cleanrooms can require very high-efficiency final filtration, depending on process and regulatory requirements.

ULPA filters may be considered in selected critical zones where specifications exceed conventional HEPA requirements.

Relevant factors include:

• Cleanroom grade
• Airflow pattern
• Terminal filtration
• Pressure drop
• Integrity testing
• Seal design
• Material compatibility
• Validation requirements

AAF and Camfil both position HEPA/ULPA filtration as part of pharmaceutical cleanroom and critical process systems.

ULPA should not automatically be presented as mandatory for pharmaceutical cleanrooms; actual requirements depend on the project specification.

 

ULPA Filters for FFUs

Fan Filter Units are a key integration point for ULPA filters.

An FFU combines:

• High-efficiency filter
• Fan
• Housing
• Control system

In this configuration, the ULPA filter must be matched to the available fan performance.

Important parameters include:

• Filter dimensions
• Efficiency class
• Rated airflow
• Initial pressure drop
• Face velocity
• Filter depth
• Frame type
• Seal
• FFU fan curve

AAF explicitly uses HEPA/ULPA filters within FFU systems for microelectronics, pharmaceutical and biotechnology cleanrooms.

Related equipment:

Fan Filter Units (FFU) →

 

ULPA Filters for Terminal and Ceiling Systems

ULPA filters are also used in cleanroom ceiling modules and terminal housings.

Common installation methods include:

• Gasket-seal systems
• Gel-seal systems
• Knife-edge housings
• Tee-grid ceilings
• Ducted ceiling modules
• Room-side replaceable modules

Camfil and AAF both offer terminal cleanroom modules designed around HEPA/ULPA filtration.

The filter should be matched to the housing rather than selected independently.

 

Gel Seal vs Gasket Seal ULPA Filters

Sealing is critical because air bypass around a ULPA filter can undermine the intended installed performance.

Gasket Seal

Gasket systems rely on controlled compression against a flat housing surface.

Important parameters include:

• Gasket position
• Thickness
• Compression
• Frame flatness
• Housing condition

Gel Seal

Gel-seal ULPA filters use a perimeter gel channel that interfaces with a compatible knife edge.

Important parameters include:

• Gel-channel dimensions
• Channel position
• Knife-edge geometry
• Filter orientation

Freudenberg currently supplies U15 ULPA filters with both PU gasket and silgel-seal configurations.

 

Aluminum Frame and Custom Frame Options

Rigid aluminum frames are common in cleanroom ULPA applications because they combine structural stability with relatively low weight.

Depending on the project, Clean-Link can support:

• Aluminum frames
• Custom frame depths
• Different filter depths
• Protective faceguards
• Gasket configurations
• Gel-seal channels
• FFU-compatible frames
• Terminal-housing designs

Frame selection should consider:

• Housing compatibility
• Seal type
• Filter weight
• Installation method
• Corrosion environment
• Cleaning requirements
• Replacement handling

 

Standard and Custom ULPA Filter Sizes

ULPA filters are often supplied in cleanroom-related module dimensions, but many OEM and replacement projects require custom sizes.

Clean-Link can support:

• Custom length
• Custom width
• Custom depth
• U15 / U16 / U17 project requirements
• Custom airflow
• Pressure-drop targets
• Frame configuration
• Gel seal
• Gasket seal
• Faceguard
• Drawing-based manufacturing
• Existing sample matching

For an existing system, send:

Filter Photo + Actual Dimensions + Class + Airflow + Seal Type

 

Replacement ULPA Filters

Replacing an existing ULPA filter requires more than matching external dimensions.

Confirm:

Two ULPA filters with identical size and efficiency class can still have different airflow resistance.

 

ULPA Filter Testing

Testing is especially important for ULPA applications because extremely low penetration levels are involved.

Depending on the project, requirements may include:

• Global efficiency testing
• Local leakage testing
• Scan testing
• Pressure-drop testing
• Individual filter reports
• Filter identification
• Traceability
• Packaging inspection

Camfil states that it leak-tests each Megalam HEPA/ULPA panel and scans the media-to-frame interface as part of its procedure. AAF likewise emphasizes individual testing and scan testing for its ULPA products.

Clean-Link can discuss testing requirements according to the confirmed filter construction and customer specification.

Do not assume all ULPA projects require the same testing package.

 

ISO 29463 and EN 1822

ULPA filter specifications commonly reference ISO 29463 and EN 1822.

These standards address high-efficiency filter classification and testing.

For U15/U16/U17 procurement, buyers should confirm:

• Standard
• Filter class
• MPPS efficiency
• Test airflow
• Global efficiency
• Local leakage requirement
• Pressure drop
• Individual test documentation

This is more meaningful than using a generic claim such as:

“99.999% efficient.”

The test standard and test condition matter.

 

ULPA Filters and ISO 14644 Cleanrooms

ULPA filters are often used in cleanrooms classified according to ISO 14644.

However, the filter class alone does not determine the cleanroom class.

Cleanroom performance also depends on:

• Airflow rate
• Air distribution
• Ceiling coverage
• Room leakage
• Particle generation
• Pressure relationships
• Process equipment
• Personnel
• Cleaning procedures

Therefore:

A U16 or U17 filter does not automatically create an ISO Class 1 or ISO Class 2 cleanroom.

The filter is one component of the cleanroom contamination-control system.

 

How to Select a ULPA Filter

Before requesting a quote, confirm:

1. ULPA class
   U15, U16 or U17.
2. Application
   Semiconductor, pharmaceutical, FFU, cleanroom ceiling, process tool, laboratory or OEM equipment.
3. Dimensions
   Actual length × width × depth.
4. Rated airflow
   Air volume per filter.
5. Pressure-drop target
   Especially important for FFU and recirculation systems.
6. Media requirement
   Glass fiber, membrane or project-specific media.
7. Frame
   Aluminum or other specified construction.
8. Seal type
   Gasket, gel seal or housing-specific arrangement.
9. Faceguard
   Upstream, downstream, both or none.
10. Testing requirement
    Efficiency, scan test, leak test, individual report or other documentation.
11. Operating environment
    Temperature, humidity, chemical exposure, AMC or outgassing concerns.
12. Quantity
    Initial project quantity and repeat requirement.

 

What to Send Clean-Link for a ULPA Quote

For a new project, send:

Class + Size + Airflow + Pressure Drop + Seal Type + Application

For a replacement filter, send:

Existing Filter Photo + Label + Actual Dimensions + Housing Photo

For an FFU project, add:

FFU Size + Fan Airflow + Available Static Pressure

For semiconductor projects, also identify any requirements related to:

• ePTFE
• Boron-free materials
• Low outgassing
• Clean packaging
• Individual filter testing

 

Why Clean-Link for ULPA Filter Projects?

Clean-Link supports ULPA filtration projects for:

• Cleanroom contractors
• Semiconductor manufacturers
• Pharmaceutical manufacturers
• FFU manufacturers
• Cleanroom equipment suppliers
• Electronics manufacturers
• Laboratories
• HVAC contractors
• Distributors
• OEM equipment manufacturers

Our support can include:

• U15 / U16 / U17 project requirements
• Mini-pleat ULPA filters
• Aluminum frames
• Gasket-seal filters
• Gel-seal filters
• Custom dimensions
• Airflow review
• Pressure-drop review
• FFU integration
• Drawing-based manufacturing
• Existing sample matching
• Testing discussions
• OEM supply
• Repeat project support

The goal is to match the ULPA class to the actual cleanroom system, airflow, pressure drop, housing and contamination-control requirement—not simply to supply the highest efficiency available.

 

Request a ULPA Filter Quote

Need ULPA filtration for a cleanroom, semiconductor fab, pharmaceutical facility, FFU, terminal housing or OEM project?

Send Clean-Link:

ULPA Class + Filter Size + Airflow + Pressure Drop + Seal Type + Application

For replacements, include:

Existing Filter Photo + Label + Housing Photo

For complex projects, drawings and testing requirements are also helpful.

Request Technical Support →

 

FAQ

What is a ULPA filter?

A ULPA filter is an ultra-high-efficiency particulate filter used in applications requiring filtration performance beyond conventional HEPA levels. ULPA classes commonly include U15, U16 and U17.

What is the difference between U15, U16 and U17?

They represent increasing minimum efficiency requirements at MPPS. U15 is rated at 99.9995% global efficiency, U16 at 99.99995%, and U17 at 99.999995% under EN 1822 classification.

What does MPPS mean?

MPPS means Most Penetrating Particle Size—the particle size at which a filter has its lowest efficiency under the test conditions.

Is ULPA better than HEPA?

ULPA offers higher filtration efficiency, but it is not automatically the better choice for every application. Airflow, pressure drop, fan capability, contamination-control requirement and project specification should all be considered.

Are ULPA filters used in semiconductor cleanrooms?

Yes. ULPA filtration is widely used in advanced semiconductor cleanrooms, FFU ceilings and process tools where extremely low particle concentrations are required. Camfil and AAF both position ULPA products specifically for semiconductor manufacturing.

Can ULPA filters be used in FFUs?

Yes. ULPA filters are commonly integrated into fan filter units. The filter pressure drop must be compatible with the FFU fan and required airflow.

Are U15, U16 and U17 filters available in custom sizes?

Clean-Link can support custom dimensions and project-specific ULPA requirements depending on media, airflow, pressure drop, seal and testing specifications.

What seal types are available?

ULPA filters can use gasket seals or gel seals depending on the housing design. The sealing method must be compatible with the installation system.

Does a U17 filter automatically create a higher-class cleanroom?

No. Cleanroom performance depends on the complete airflow and contamination-control system, not only filter class.

Why does pressure drop matter in ULPA filters?

ULPA filters operate at extremely high efficiencies. Their resistance affects airflow, fan demand and FFU operation, so pressure drop should be reviewed together with efficiency.

Do ULPA filters require individual testing?

Many critical applications specify individual scan or leak testing. The exact testing package should follow the project specification.

What information is needed for a quote?

Start with ULPA class, dimensions, airflow, pressure drop, frame, seal type, application, quantity and testing requirements.