The best air filter for a cleanroom is generally a high-efficiency particulate air (HEPA) filter, with H13 and H14 grades commonly specified for environments requiring stringent airborne particle control.
However, the most suitable filter depends on the cleanroom’s ISO classification, the processes taking place within it, airflow requirements, and applicable industry standards
For environments requiring exceptionally high levels of particulate removal, ultra-low penetration air (ULPA) filters may also be considered.
Choosing the right filtration system is essential for maintaining a controlled environment, protecting sensitive processes and supporting consistent cleanroom performance.
Why is Air Filtration Important in a Cleanroom?
Cleanrooms are designed to control the concentration of airborne particles within a defined environment. They are widely used across industries including pharmaceutical manufacturing, biotechnology, healthcare, electronics, and scientific research.
Even small airborne particles can compromise sensitive manufacturing processes, affect product quality or introduce unwanted contamination.
Air filtration is therefore a fundamental part of cleanroom design. By removing particles from the air supplied to the controlled environment, filtration systems help maintain the required cleanliness conditions.
However, filter efficiency is only one consideration. Airflow distribution, room pressure, contamination sources and ongoing maintenance all contribute to overall cleanroom performance.
What Type of Air Filter is Best for a Cleanroom?
For many cleanroom applications, HEPA filters are the preferred choice because of their ability to capture very fine airborne particles.
HEPA filters are available in different efficiency classifications, allowing filtration performance to be matched to the requirements of the application.
H13 HEPA Filters
H13 filters have a minimum overall efficiency of 99.95% at the most penetrating particle size (MPPS), according to the EN 1822 classification system.
They are used in a range of controlled environments where high-efficiency particle filtration is required.
H14 HEPA Filters
H14 filters provide a higher minimum overall efficiency of 99.995% at MPPS.
They may be specified for applications requiring more stringent particle control, including certain pharmaceutical, healthcare and precision manufacturing environments.
ULPA Filters
UPLA filters offer even higher levels of particle removal than HEPA filters and may be used in specialised applications with particularly demanding cleanliness requirements.
However, higher filtration efficiency does not automatically make a filter the best option. Pressure drop, airflow requirements, system design and operating costs must also be considered.
HEPA vs ULPA Filters: What’s the Difference?
The primary difference between HEPA and ULPA filters is their particle removal efficiency.
The following table compares three common high-efficiency filter classifications under EN 1822.
| Filter Classification | Minimum Overall Efficiency at MPPS |
|---|---|
| H13 HEPA | 99.95% |
| H14 HEPA | 99.995% |
| U15 ULPA | 99.9995% |
MPPS refers to the most penetrating particle size, at which the filter exhibits its lowest particle collection efficiency. These figures represent overall efficiency classifications under EN 1822; individual filter specifications and applicable test standards should always be confirmed.
Although ULPA filters provide higher efficiency, they were not necessary for every cleanroom. Selecting an unnecessarily restrictive filter may increase system resistance and operating costs without delivering a meaningful improvement in the required cleanliness performance.
The correct choice depends on the application and the design of the complete air handling system.
How Does ISO Cleanroom Classification Affect Filter Selection?
Cleanrooms are classified according to the concentration of airborne particles permitted within the controlled environment.
ISO 14644-1 establishes the framework for classifying air cleanliness by particle concentration, with ISO Class 1 representing the most stringent particle cleanliness classification.
Different cleanroom classifications require different levels of contamination control.
For example, an ISO Class 8 cleanroom may have different filtration and airflow requirements from an ISO Class 5 cleanroom used for more sensitive processes.
Importantly, ISO 14644-1 does not prescribe a single HEPA filter grade for every cleanroom classification.
Filter selection must account for the complete cleanroom design, including airflow patterns, air change rates, particle generation, and the required operating conditions.
This is why cleanroom filtration should be specified as part of an integrated contamination control strategy rather than selecting a filter based on efficiency alone.
What Should You Consider When Choosing a Cleanroom Air Filter?
Several factors should be evaluated before selecting a filter for a new or existing cleanroom.
1. Required Cleanliness Classification
The required ISO classification provides a starting point for determining the level of airborne particle control needed.
Different applications may also have additional regulatory or process-specific requirements that influence filter selection.
2. Filter Efficiency
The appropriate HEPA or ULPA efficiency grade should be selected based on the application’s contamination control requirements.
Higher efficiency is not necessarily better if it introduces unnecessary system resistance or is unsuitable for the equipment.
3. Airflow and Pressure Drop
Filters create resistance as air passes through them. Selecting a filter with an unsuitable pressure drop can affect airflow performance and increase energy consumption.
Both initial pressure drop and the expected increase in resistance during operating should be considered.
4. Filter Configuration and Installation
Cleanroom filters are available in different constructions, sizes, and configurations.
The selected filter must be compatible with the air handling system, mounting arrangement, and available installation space.
Correct sealing and installation are essential to prevent unfiltered air bypassing the filter.
5. Testing and Maintenance
Filtration performance should be considered throughout the equipment’s operating life.
Appropriate testing, inspection, and maintenance help identify filter damage, leakage, excessive resistance, or other issues that could affect cleanroom performance.
Filter replacement decisions should be based on operating conditions, performance assessments, and applicable maintenance requirements rather than a fixed replacement schedule alone.
Choosing Cleanroom HEPA Filters in Australia
Australian facilities should consider relevant local standards, project specifications, and industry-specific regulatory requirements when selecting cleanroom filtration.
For example, AS 4260 addresses high-efficiency particulate air filters, while ISO 14644-1 provides the framework for classifying cleanroom air cleanliness.
Depending on the application, additional requirements may apply to the design, testing, qualification, and ongoing operation of controlled environments.
Working with an experienced Australian filtration manufacturer can help facilities select filters suited to their operating conditions, equipment configuration, and performance requirements.
Australian-Manufactured HEPA Filtration from AES Environmental
AES Environmental is an Australian engineering and manufacturing company specialising in air filtration, cleanroom technology, and contamination control solutions.
At its manufacturing facility in Minto, New South Wales, AES produces a range of Absolute HEPA Filters for specialist filtration applications.
The range includes rigid box, panel, and V-cell configurations, with filter efficiencies from E10 through to H14. ULPA filtration options are also available on request.
AES’s local manufacturing and engineering capabilities support a variety of filter sizes and configurations to suit specific equipment and installation requirements.
Beyond filter manufacturing, AES provides technical expertise in contamination control, equipment testing, validation and ongoing servicing.
This combination of manufacturing, technical knowledge and ongoing support helps customers consider filtration performance throughout the equipment lifecycle, from initial specification through to maintenance and replacement.
Frequently Asked Questions About Cleanroom Air Filters
There is no single HEPA filter grade prescribed by ISO 14644-1 for every ISO Class 5 cleanroom. H13 and H14 filters may be considered depending on the application, airflow design and contamination control requirements. The final specification should be determined by the cleanroom designer or qualified specialist, taking into account applicable industry standards and process risks.
H14 filters provide higher minimum particle removal efficiency than H13 filters under EN 1822. However, H14 is not automatically the better choice for every cleanroom. The appropriate grade depends on the required cleanliness performance, system airflow, pressure drop, and operating conditions. Selecting a filter with higher efficiency than necessary may increase system resistance without providing a practical benefit.
HEPA filtration is widely used in cleanrooms, particularly where stringent airborne particle control is required. However, the appropriate filtration arrangement depends on the cleanroom classification, application and overall ventilation design. Some specialised environments may require ULPA filtration, while other controlled spaces may use different filtration configurations.
There is no universal replacement interval suitable for every cleanroom HEPA filter. Testing and replacement requirements depend on the application, applicable standards, operating conditions, pressure drop and filter integrity. Filters may require replacement if they fail integrity testing, become damaged or develop excessive resistance. Regular monitoring and appropriate maintenance help maintain reliable cleanroom performance.
Need Advice on Cleanroom Air Filtration?
Selecting the correct filtration system involves more than choosing the highest available efficiency rating.
From filter performance and airflow requirements to installation and ongoing maintenance, each element plays a role in achieving reliable cleanroom operation.
AES Environmental provides Australian-manufactured HEPA filtration products alongside technical expertise in air filtration, contamination control and cleanroom equipment.
Whether you’re specifying filtration for a new cleanroom, replacing existing filters, or reviewing the performance of an existing system, our team can help you explore suitable options.