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NAFA Guide To Air Filtration. Chapter 5 HEPA, ULPA and Super ULPA Filters presented by the National Air Filtration Association. Fifth Edition. HEPA and ULPA Filters. HEPA Filter History.
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NAFA Guide To Air Filtration Chapter 5 HEPA, ULPA and Super ULPA Filters presented by the National Air Filtration Association Fifth Edition
HEPA Filter History • The first HEPA was developed in the 1940’s under a classified government project for filtration of radioactive contaminants. • They were required as part of the Manhattan Project which developed the atomic bomb. • The original filters were quite bulky and inefficient as compared to current HEPA filters. Some had asbestos fibers • After WWII, HEPA filter technology was declassified with commercial manufacturing beginning in the 1950’s.
Approx. HEPA Filter Applications in Industry Pharm/Biotech/ 18% Aerospace/ Auto 6% Process/Food/ Optical 24% Medical/Hospital Device 21% Electronics/Micro 31%
High Efficiency Particulate (HEPA) Air Filter “Throwaway extended-medium dry-type filter in rigid frame, when tested at rated airflow having minimum particle-collection efficiency of 99.97% for 0.3 micrometer (µm) mass median diameter particles of DOP when tested in accordance with MIL-STD-282 particles of thermally-generated DOP particles or specified alternative aerosol.”
99.999 99.99 99.97 99 90 50 PARTICLE DIAMETER (MICRONS) 10 0.01 0.1 1.0 10.0 HEPA Filter Mechanisms THEORETICAL HEPA FILTER COLLECTION EFFICIENCY COLLECTION EFFICIENCY%)
Components of a HEPA Filter • Media • Separators • Filter pack • Sealant • Framing (cell sides) • Gasketing
Wet Laid Glass Fiber Media Engine Filter- cellulose paper HEPA Filter microglass fibers
Aluminum Separators Corrugation heights from .06” to .20” deep Mini-Pleat Coated String Embossed Media Ribbon of Media Adhesive Bead Separator Styles Minipleat using string separators
Filter Sealants • Rubber Based • Urethane • Epoxy • Hot Melt • Silicone
Particle Board Fire Retardant Standard Plywood Fire Retardant Standard Extruded Aluminum Formed Sheet Metal Stainless Steel Galvanized Steel Aluminum Frame Materials
Filter Performance • Filter Performance measures penetration (then converted to efficiency) • Most Penetrating Particle Size (MPPS) for differing flow rates • Each filter is tested – (non-destructive test)
Filter Performance & Application HEPA • 99.97% for 0.3 micron particles MMD (Type A) • 99.99% for 0.3 micron particles MMD (Type C) ULPA Minimum Particle Collection Efficiency • 99.999% 0.1-0.2 Micrometer Particles (Type F) SUPER ULPA • 99.9999% on MPPS (Type G) See page5.6- for all filter types
Gasketing • Closed-cell Neoprene Gasket • Non-Newtonian Gel Seal
Terminal HEPA Filters Room-side Replaceable Disposable Terminal Modules Modules
Proper Training • Do Not Change Bag In/Bag Out Filters Without Proper Hands-on Instruction, Training, and Accreditation – NAFA Certified Technician, Level II
HEPA Filter Are • Most Always Second or Third Filter Bank • Pre-filtered with Pleat and or MERV 15/16 Filter • Using Neoprene Gasket - Always In Locking HEPA Filter Holding Frame • Using Gel Seal – held in place • Always Exact Size – Not Nominal • Always Requires Special Handling, Installation, and Testing
HEPA Filters Because they catch everything, always wear respirator protection when changing any type of HEPA filter
Sample Questions • In order to be classified a HEPA filter, the efficiency must be at least? 99.97% on 0.3 micrometer particles • ULPA stands for? Ultra-Low Penetration Air filter • Two types of gasketing for HEPA’s are? Closed Cell Neoprene and Non-Newtonian Gel Seal
Thank you. • Other Questions?