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Selecting High Efficiency filters for the Pharmaceutical/Biotech Industry


The following guidelines on selecting high efficiency air filters for the pharmaceutical industry mainly deals with filters in the HVAC system (i.e. make up air and terminal and exhaust filtration). The guide, while general, is a Camfil Farr recommendation based on our experience supplying filtration systems to the industry.

 Camfil Farr's Pharmaseal
There are many different types of processes in pharmaceutical manufacturing, with different demands and concerns placed on the filtration systems.  In contrast, a  semiconductor fab has a standard design, while in pharma there are probably no two cleannroom facilities the same, unless its for the same owner and process.

We are concerned with many issues when we talk about filtration in the pharmaceutical industry as follows:

  • global & local standards
  • filter economy
  • filter efficiency
  • location of filters
  • environmental effects of used filters
  • classification of the room
  • testing of filters

This article will focus on testing and standards.

Testing of filters (both in house & in situ tests)

There are many reason why filters ‘fail’ on site.  These include bad packing, transport damage, inexperienced personnel handling filters, and finally, and probably most common, wrong selection or specification of filters. This is understandable due to the many different standards and client demands.

Example’s of filter testing protocols:

1. EN 1822 High efficiency air filters (HEPA & ULPA) classification and test of filters.

Eurovent 4/4 (replaced by EN 1822, however still used and misunderstood especially when specifying efficiency, Eurovent uses NaCl (0.65 micron diameter) whereas EN1822 uses the most penetrating particle size (typically 0.15-0.2 micron diameter). The resulting efficiency can be in the range of 99.997 for 0.65 micron particles and 99.95 for MPPS for the same filter.

Eurovent 4/4 is a volumetric test and may not detect pinhole leaks within the filter, whereas EN1822 involves a full media scan test, on the higher grades of HEPA filters they would be the natural choice for pharmaceutical use.

Care, however, should be used when selecting HEPA filters for areas that are required to be in-situ tested. (i.e. factory scan test and meeting requirements of the in-situ scan test, for instance the 0.01% penetration requirement).

Other testing protocols include:

2. IEST-RP-CC001.3 HEPA & ULPA Filters (1993)
3. IEST-RP-CC006.2 Testing Cleanrooms (1997)
4. IEST-RP-CC021.1 Testing HEPA & ULPA filter media (1993)
5. IEST-RP-CC034.1 HEPA & ULPA filter leak test (1999)

It is not the purpose of this article to discuss each individual recommendation.  However, discussing each project on a ‘case by case’ basis with the owner, designer, contractor and supplier and ‘pooling’ the collective knowledge before a detailed specification is written can eliminate costly mistakes.

Table 1: Standards applicable to the American & European markets

  Classification & Particle
Counting in The Room
Filter Classes Testing Filters
 GMP/Europe ISO-14644 EN-1822 EN-1822

Standards International & National:

Today we are getting closer and closer to having one standard for cleanroom classification meeting the requirements of  GMP for Europe, the US and Asia.  They generally follow the aforementioned standards. Many countries in Asia will use their own national standards.  For example, in Japan the JACA and in Australia AS1386.  These standards are generally applied to manufacturers located within the borders of the region.  However, if an American or European manufacturer invests in Asia and intends to ship product to their home country/continent, they will generally follow their standards (i.e. GMP, or FDA).

Examples of cleanroom classification standards:

1. ISO 14644 (1-9), introduced in 2000
2. US FED STD 209D 1998 - FDA’s Cleanroom classification (edition D was replaced by Edition E in 1992)
3. US FED STD-209E, 1992 - FDA’s Cleanroom classification
4. GGMP PIC/EEC Annex 1 (January 1997) Cleanroom classifications

Below is a general comparison of these standards

1 M 1.5 Class 3  
10 M 2.5 Class 4  
100 M 3.5 Class 5  A & B
1000 M 4.5 Class 6  
10,000 M 5.5 Class 7 C
100,000 M 6l5 Class 8 D


Selecting, high efficiency filters and accessories (housings, mounting frames etc) is not easy. One must consider many parameters including filter efficiency, application, lifetime, running costs, equipment costs, accessibility, etc. Camfil Farr has developed many software programs for optimizing filter selection.  The programs include of hepa/ulpa selection, cleanroom design, chemical/carbon selection, and LCC (life cycle cost, make up air). Most of this software is available upon request.

With their enormous R&D budgets, pharmaceutical and biotechnology companies play an extremely important role in the future of health care. Filters are and will remain a critical part of the production of their products.  Camfil Farr is proud to be the leading supplier of ‘clean air solutions’ to the pharmaceutical and biotechnology industries. For further information, contact your nearest Camfil Farr sales office and or visit our web site at

Sean O' Reilly
Bio-Pharma Segment Manager
Camfil Farr Group