Selection, Installation and Maintenance of HEPA and ULPA Filters in the Pharmaceutical Industry
The fundamental purpose of a cleanroom in pharmaceutical production is to protect the manufactured product from contamination. The economic survival of the manufacturer depends on the safety of the finished product, so it is crucial to know the potential sources of contamination, including the working environment itself.
Supply air quality requirements have increased, especially in the pharmaceutical industry where systematic methods are needed to maintain specific air quality parameters, such as the concentration of suspended particulate matter and the permissible amount of viable microorganisms.
Supply air filtration is a central aspect of cleanroom technology. To achieve the appropriate cleanliness levels, high efficiency filters, mainly HEPA and ULPA, are used.
HEPA Filters
- Minimum efficiency of 99.97% for 0.3 µm particles.
- They operate on the principle of diffusion.
- Constructed of folded submicron fiberglass media, separated by aluminum or Kraft paper.
- Initial pressure drop: about 1 inch of water column.
- They are not MERV rated; they are tested and certified to meet specific efficiencies.
- In the pharmaceutical industry, H14 filters are used according to EN 1822 (efficiency 99.975%).
ULPA Filters
- Higher efficiency than HEPA: 99.999% for 0.3 µm particles.
- Boron-free versions are available with 99.9997% efficiency down to 0.12 µm.
- Used in Class 1 and 10 rooms in electronics and semiconductors.
- In pharma, classes U15-U17 (EN 1822) are used with higher efficiency than H14.
Filter Selection by Cleaning Class
The type of cleaning determines the type of filter required:
- Grade A: laminar flow with HEPA filters.
- Grade B: filtered air with less stringent requirements.
- Grade C and D: higher particle limits; HEPA still common.
Installation Considerations
- Ceiling installation or individual housings with inverted T-bracket system.
- It is important to ensure airtight sealing with suitable gaskets or sealants.
- Placement near the extraction point to reduce contamination.
- Allow easy and safe changeover. In bio-hazardous areas, use BIBO (Bag-In/Bag-Out) systems.
Maintenance and Replacement
- Efficiency must be measured and certified.
- Verification of seals every 90 days; full scan every six months.
- Monitor pressure drop to detect particle accumulation.
- Evaluation with methods such as particle counting and DOP.
- Well-documented changes without breaking the integrity of the system.
- Use of clamp-on filters and extraction bags for safety.
Pre-filters
Recommended for HEPA and ULPA protection by capturing large particles.
Conclusion: Proper selection, installation and maintenance of HEPA and ULPA filters are essential to ensure air quality in pharmaceutical cleanrooms. These filters are critical in HVAC systems designed to maintain positive pressure, airflow and environmental cleanliness.
