6 The type of activities within a particular pharmaceutical processing environment will determine the level of cleanliness that is required. To ensure that stringent air quality levels for safely manufacturing medicinal products are met, a carefully designed air filtration system is vital. Based on their performance efficiency, air filters are classified according to two widely accepted standards, ASHRAE 52.2 and the Institute of Environmental Sciences and Technology (IEST) Recommended Practice (RP) IEST-RP-CC001. Internationally EN1822 and the ISO standard 29463 (High Efficiency Filters and Filter Media for Removing Particles in Air) is the accepted classification method (Table 1). ASHRAE 52.2 ASHRAE Standard 52.2 describes a method of laboratory testing to measure the performance of air filters as a function of particle size. The method of testing measures the performance of air filters in removing particles of specific sizes as the filters become loaded by standard loading dust. The dust is fed at intervals to simulate accumulation of particles during service life. The standard defines procedures for generating the aerosols required for conducting the test. The standard also provides a method for counting airborne particles of 0.3 micrometers to 10 micrometers upstream and downstream of the air filter in order to calculate removal efficiency by particle size. The overall reporting value of the air filter is expressed as Minimum Efficiency Reporting Value (MERV) (Table 2). AAF Flanders offers a broad range of ASHRAE 52.2 compliant and energy efficient air filters as prefiltration to final HEPA filters. The choice of prefiltration will determine the cleanliness of the air entering the final filter, and therefore its lifetime. Classifying Air Filters Standard 52.2 Minimum Efficiency Reporting Value (MERV) Complete Average Particle Size Efficiency, % in Size Range, µm Average Arrestance, %, Addendum B Range 1 0.30 - 1.0 Range 2 1.0 - 3.0 Range 3 3.0 - 10.0 1 n/a n/a E3 < 20 Aavg. < 65 2 n/a n/a E3 < 20 65 ≤ Aavg. < 70 3 n/a n/a E3 < 20 70 ≤ Aavg. < 75 4 n/a n/a E3 < 20 75 ≤ Aavg. 5 n/a n/a 20 ≤ E3 < 35 n/a 6 n/a n/a 35 ≤ E3 < 50 n/a 7 n/a n/a 50 ≤ E3 < 70 n/a 8 n/a n/a 70 ≤ E3 n/a 9 n/a E2 < 50 85 ≤ E3 n/a 10 n/a 50 ≤ E2 < 65 85 ≤ E3 n/a 11 n/a 65 ≤ E2 < 80 85 ≤ E3 n/a 12 n/a 80 ≤ E2 90 ≤ E3 n/a 13 E1 < 75 90 ≤ E2 90 ≤ E3 n/a 14 75 ≤ E1 < 85 90 ≤ E2 90 ≤ E3 n/a 15 85 ≤ E1 < 95 90 ≤ E2 90 ≤ E3 n/a 16 95 ≤ E1 95 ≤ E2 95 ≤ E3 n/a Table 1: ISO 29463 Filter Classes and Equivalents ISO Filter Class Efficiency IEST* EN 1822 ISO 15 E >95% – H 11 ISO 20 E >99% – ISO 25 E >99.5% – H 12 ISO 30 E >99.9% – ISO 35 H >99.95% – H 13 – >99.97% A,B,E,H,I – ISO 40 H >99.99% C,J(K) ISO 45 H >99.995% K H 14 ISO 50 U >99.999% D ISO 55 U >99.9995% F U 15 ISO 60 U >99.9999% G ISO 65 U >99.99995% G U 16 ISO 70 U >99.99999% G ISO 75 U >99.999995% G U 17 * IEST Types A, B, C, D, and E are classified per test results using photometers (Mil Std 282). Types F, G, H, I, J, and K are classified per test results using particle counters. IEST-RP-CC001 To ensure the highest levels of air purity, pharmaceutical processes need to rely on high efficiency particulate air filters as terminal filters. These air filters are subject to classification according to IEST-RP-CC001 (HEPA and ULPA filters). This recommended practice (RP) covers basic provisions for HEPA and ULPA filter units as a basis for agreement between customers and suppliers. Table 2: Air Filter Classification per ASHRAE 52.2.
RkJQdWJsaXNoZXIy MjgzNzA=