Which pharmaceutical clean area and isolator should be HEPA or ULPA?

There is a clear difference between filter selection in the pharmaceutical industry and general industrial clean rooms: the choice here is not only a technical issue, but also involves regulatory systems and verification documents.

Under the GMP system, filters are part of equipment verification. Changing to another level, not just replacing a part, may trigger a re-verification process. Therefore, before discussing 'choosing HEPA or ULPA', we must first understand: what is the purpose of this location, what is the management standard, and where is the verification boundary.

Clean area and isolator are not the same thing

These two scenarios are often mentioned together, but their filtering requirements are quite different.

Pharmaceutical clean area : Usually room-level control, supply air end filtration, return air treatment, and pressure gradient are common concerns. The filter configuration must meet the cleanliness level and sterility requirements of the area.

Isolator : It is a closed micro-environment, and the supply air and exhaust air are usually filtered. The core function of an isolator is product protection or personnel protection, of which filtration is only one part. If there is a biological risk at the exhaust end, the isolation and disposal methods when replacing the filter element should also be considered.

The verification requirements are also different between the two. Clean areas are inspected by room, and isolators are verified by equipment. The filtration solution in the clean area cannot be moved directly to the isolator.

Different devices have different focus on filtering configuration.

Air supply at the end of the room : pay attention to air volume distribution, air flow organization and pressure difference. The filter grade should match the regional requirements, and sealing and leak detection should be performed according to the clean room plan. Products can be referenced HEPA/ULPA Air Filter Instructions.

Isolator air supply : The space is small and the air volume is low. The size and resistance of the filter must match the internal structure of the isolator. The air supply end is usually equipped with HEPA, and the specific grade is confirmed according to process requirements.

Isolator Exhaust : If dealing with biohazardous air streams, the exhaust-side filter may require a bag-in-bag-out configuration or an isolator-replaceable design. This aspect not only looks at the filtration efficiency, but also the safety and verifiability of the replacement operation.

Some isolators are also equipped with ULPA for use in scenarios with higher requirements for particle control. The specific selection is based on process documents and equipment usage, not unified regulations.

Check the compatibility of materials and cleaning agents

Pharmaceutical equipment frequently involves cleaning, disinfection and decontamination operations. The material of the filter may be affected during these processes.

Sealants and gaskets : Cleaners, disinfectants, hydrogen peroxide vapor, etc. may affect the performance of the colloid and sealing materials. When selecting, confirm the suitability of the material under specific concentration, temperature, humidity and contact time.

Outer frame : Corrosion-resistant treatment of stainless steel or aluminum alloy, which must match the cleaning method.

Filter material : Some decontamination processes may have an impact on the filter material. You need to confirm the applicable conditions with the supplier.

This information should come from project process documents rather than general experience. Different pharmaceutical companies use different cleaning agents and disinfection methods, and the applicability of the same filter in different projects may also be different.

When modifying and replacing, don’t just look at the filter element

If your existing equipment is to be upgraded from HEPA to ULPA, or to a different type of filter, there are a few things to confirm in advance.

Effects of resistance changes on the system. The resistance of ULPA is usually higher than that of HEPA of the same size, so check the fan margin and pressure control capability. The internal space of the isolator is small and the air volume is inherently limited. Increased resistance may affect the number of air changes and pressure difference stability.

Device authentication boundaries. Does changing filter grade trigger revalidation? This judgment must be carried out according to the project's change control procedure and cannot be decided unilaterally by the supplier.

Executability of replacement operations. The internal space of the isolator is compact. Whether the new filter element can be installed, whether it can be safely taken out, and whether the leak detection path is accessible must be confirmed in the planning stage.

Relevant records need to be updated. Equipment verification documents, maintenance records, and spare parts lists must correspond to the new filter specifications. involving FFU fan filter unit or When the EFU equipment-side fan filter unit is used, the corresponding relationship between unit parameters and filter element data must also be updated simultaneously.

Verification must be performed according to the project system

Filter verification for pharmaceutical projects cannot be completed by the supplier providing a report.

The filter itself : efficiency, resistance, integrity, supported by test data of the corresponding model.

Installation status : Sealing and leak detection after installation shall be carried out according to the project verification plan.

System functions : The pressure control, air flow direction, and alarm functions of the isolator fall within the scope of equipment verification.

Operating status : Cleanliness or sterility guarantee under dynamic conditions, confirmed according to process requirements.

These items are verified and recorded separately. Certification of a filter's grade is not a substitute for verification of equipment functionality, nor vice versa. The specific testing methods and judgment standards shall be subject to the applicable specifications and quality documents of the project.

Project judgment example

An isolator was originally equipped with HEPA, but due to process adjustments, it was considered to be replaced with a higher grade filter.

When dealing with this change, do two things first: confirm whether the craft really needs a higher level, and whether the existing system can withstand the resistance change. If the process documents clearly require an upgrade, then evaluate the scope of impact according to the change control process - which may include air volume, pressure difference, replacement operations and verification documents.

Don't upgrade yourself just because 'a higher level is safer'. In the pharmaceutical industry, any change needs to be evaluated and validated, and filter replacement is no exception.

Selection and Acceptance Checklist

About Aili Industrial’s pharmaceutical cleanliness package

Filter selection for pharmaceutical projects requires clear process requirements and verification boundaries. Once this part is clear, you will know what conditions the filter needs to meet.

Aili Industrial's manufacturing system covers filters, motors, fans, control systems and complete machine assembly, and can provide HEPA/ULPA products of different grades and supporting air supply equipment. Filter can be used with FFU fan filter unit、Check the installation interface and sealing method of the EFU equipment-side fan filter unit together to facilitate unified confirmation of the equipment-side and room-side configurations.

For projects involving pharmaceutical processes, selection, maintenance and verification should follow the specifications and quality documents applicable to the project. Providing process usage, regional requirements, equipment structure and verification methods during the inquiry will help confirm the appropriate configuration. Specific performance is subject to product technical data and project acceptance results.