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We provide superior filtration solutions to improve the quality of life. Filtration Standards Presentation Dan Woodman April 23, 2010. Air filters. Dust filters. High efficiency air filters. Group. Coarse dust filters. Fine dust filters. High Efficiency Particulate Air (HEPA) filters.
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We provide superior filtration solutions to improve the quality of life Filtration Standards Presentation Dan Woodman April 23, 2010
Air filters Dust filters High efficiency air filters Group Coarse dustfilters Fine dustfilters High EfficiencyParticulate Air(HEPA) filters Ultra LowPenetration Air(ULPA) filters Sub-group EN 779G1 - G4 52.2 MERV 1-4 EN 779F5 - F9 52.2 MERV 9-16 EN 1822H10 - H14 EN 1822U15 - U17 FilterClass Particle Filtration Standards Overview • KEY POINTS • EN 1822 is used for HEPA and ULPA • Europe uses EN779, US uses ASHRAE 52.2 Many Different Standards Exist
What is ASHRAE 52.2 • Ranking and Reporting • 16 MERV reporting values using Minimum Efficiency of 3 groups of average particle ranges (E1, E2, E3), average arrestance applied on MERV 1 – 4 Efficiency Challenge Aerosol • Neutralized Solid Potassium Chloride (KCl) particles ranging in diameter from .3 to 10 μm Particle Counting • Counting done alternately with dust loading intervals and 12 channels measured at each interval. Four channels averaged for each of 3 ranges (E1 from 0.3 to 1 μm, E2 from 1 to 3 μm, and E3 from 3 to 10 μm.) • Arrestance Challenge Dust • ASHRAE dust (Combined Arizona road dust, carbon black and cotton linters) Efficiency / DHC / Pressure Drop Relation • Initial preload of 30 grams or ΔP of +10 Pa, then load in 25% increments of final ΔP. Arrestance reported on MERV 1 – 4 Final Pressure Drop • At least twice the initial ΔP or as specified by MERV Range, whichever is greater.
Gravimetric Filters Arrestance Course Filters E3 Emphasis Medium Filters E2 Emphasis Fine Filters E1 Emphasis ASHRAE 52.2 MERV Table
E2 Establishes the MERV E1 Establishes the MERV E1 Doesn’t Factor ASHRAE 52.2 MERV Example Minimum Range Used for Reporting
ASHRAE 52.2 MERV 8-11 Issue • KEY POINTS • One % drop in E3 can result in 3 MERV Level Change First Run E1 = 33 % E2 = 72 % E3 = 86 % Second Run E1 = 35 % E2 = 71 % E3 = 84 % MERV 11 MERV 8 Source: Robert Burkhead, 2004 Correction Needed to Fix this Phenomenon
ASHRAE 52.2 MERV 8-11 Issue *One Option Being Reviewed Modification is now on discussion
What is EN 779 Ranking and Reporting • Nine filter classes based on average arrestance (G1 - G4) or 0.4 μm efficiency (F5 - F9) Efficiency Challenge Aerosol • Neutralized liquid DiEthylHexylSebacate (DEHS) or equivalent particles ranging in diameter from 0.2 to 3 μm Particle Counting • Counting done alternately with dust loading intervals using a minimum 5 bands measured at each interval. Arrestance Challenge Dust • ASHRAE dust (a blend of A2 fine, carbon black and cotton linters) Efficience / DHC / Pressure Drop Relation • Initial preload of 30 grams, then a minimum of four evenly distributed measuring points. Arrestance and DHC reported on all tests. Final Pressure Drop • Max. 250 Pa for “coarse” grade filters (G1 – G4), 450 Pa for “fine” grade filters (F5 – F9)
Load with ASHRAE Dust in steps until final P Measure Initial: P, Efficiency Measure P, Efficiency, Arrestance between loadings Calculate Average Efficiency and Arrestance Report Initial, Average values with graphs attached Measure Final: P, Efficiency, Arrestance Basic Test Scheme to EN 779
Average 63 % Dust feed (ASHRAE dust) in g Efficiency as a Function of the Dust Feed
EN779 Filter Class Table • KEY POINTS • Two groupings determined from Average Arrestance or Efficiency • Average over loading is used for Filter Class Average Efficiency or Arrestance Used Over Dust Loading Curve
Sample of a synthetic micro fiber nonwoven dipped into isopropanol Synthetic micro fiber nonwoven after storage in isopropanol Annex A: Electrostatic discharging procedure • Any treatment to give a completely discharged material may be used. • In detail the treatment with isopropanol (IPA) is described. • The initial efficiency of a treated and untreated media sample are measured and have to be stated on the test report. Information Reporting Only
Annex B: Shedding from filters (informative) • The term „shedding“ comprises three separate aspects of filter behavior. • Some or all of these phenomena are likely to occur to some extent during the life cycle of an installed filter. • Particle bounce • Release of fibers or particulate matter from filter material • Re-entrainment of particles Information Reporting Only
Draft of the new EN 779 • Key Points • New medium filter class introduced • Discharge testing for F7-F9 based on IPA = New in the current draft of EN 779:2010 Introduction Later this Year
Comparison of ASHRAE 52.2 and EN779 Very Different Standards
Comparison of ASHRAE 52.2 and EN779 Source: Robert Burkhead, 2004 No Direct Comparison Exists
Take Home Points • The ASHRAE method 52.2 • Popularly used in US • Currently does not distinguish charged products • Uses a solid aerosol challenge • European method EN 779:2002 • Used in Europe and global application is being sought • Does provide charged fiber characterization • Uses a liquid aerosol challenge • Significant other differences
Performance Criteria of an HEPA/ULPA Filter • Pressure drop at nominal volume flow rate • Integral collection efficiency for the particle size with the highest penetration(MPPS = Most Penetrating Particle Size) at nominal volume flow rate • Local collection efficiencies for the particle size with the highest penetration(MPPS) at nominal volume flow rate • Freedom of leaks as of filterclass H13 according to EN1822
part 3 part 4 part 5 part 1 Test method to EN 1822 • Determination of the MPPS at the plane mediumat the nominal media velocity • Measurement of the pressure drop • Measurement of the fractional efficiency curve T(x) as afunction of the particle size in the range 0,05µm to 0,5µm • Determination of MPPS as minimum of the curve • Leakage test of the complete filter elementat nominal air flow rate (only HEPA und ULPA) • Scan test: Measurement of the local efficiencies • Alternatively for HEPA: Oil Thread Leakage Test or 0.3 - 0.5 μm Particle Efficiency Leak Test (only H13 & above) • Measurement of the overall efficiency and the total pressure drop of the complete filter element atnominal flow rate • Classification and supply of a test certificate
New in EN 1822:2009 • Introduction of group E (EPA) • Filter classes H10-H12 have been renamed to E10-E12 • Clear definition of group E (no individual test required, only factory test certificate, spot checks as part of a quality control system equivalent to ISO 9001) • New Annexes in part 4 (Leakage test methods) • Annex D (informative): Leak Test with solid PSL Aerosol • Annex E (informative): 0.3 - 0.5μm Particle Efficiency Leak Test • New Annexes in part 5 (measurement of efficiency) • Annex A (informative): Testing and classification method for filters with MPPS ≤ 0.1μm (e.g. membrane medium filters) • Annex B (normative): Testing and classification of filters using media with (charged) synthetic fibers
Filter classes and Efficiencies to EN 1822:2009 1) Vendor and buyer can agree upon lower local values than mentioned in the table 2) Determination of freedom from leaks can also be carried out by the Oil Thread Leakage Test 3) Determination of freedom from leaks can also be carried out by the 0.3 - 0.5 μm Particle Efficiency Leak Test
different interpretation of the test results InitialArrestance SF-C1 – SF-C4 Minimum efficiency SF-F5 – SF-F7 Minimum efficiency SF-E8 – SF-E10 EN 779: F7 – F9 EN 779: G3 – F6 EN 1822: H10 – H12 fine coarse HEPA Proposed ISO/TC142/WG9 Proposed test and classification system for static filters for gas turbine • One common test method • Loading dust is AC Fine, results are: • Initial arrestance (gravimetric 50g loading), • Initial efficiency DEHS (0.4µm) (untreated + treated) • Efficiency DEHS (0.4µm) after 50g dust and final • DHC
Proposed ISO/TC142/WG9 • Initial arrestance: The gravimetric efficiency is the weighted (mass) removal of loading dust after 50 g of dust load. • Minimum of all measured 0.4μm efficiency values, being either: • Initial filter efficiency • Filter efficiency after 50 g dust loading • Filter efficiency at 625 Pa final pressure drop • Media efficiency after conditioning
Future Changes to Standards • ISO TC142 WG3 Discussed the Following Concept for Filter Class: • KEY POINTS • Discharge Efficiency would be included as an adjustment • Metric would be PM2.5 and PM10-2.5 efficiency • Measure the clean filter efficiency in each particle size range. • Measure the clean media efficiency on flat sheet of media used in the filter. • Measure the discharged media efficiency on the flat sheet. • Use ½ of the efficiency drop between initial flat sheet efficiency and discharged flat sheet efficiency in each particle size range to adjust filter efficiency.
Future Changes to Standards • KEY POINTS • Standardized PM10 Curve Needs to be Determined • Mass distribution used by governments for IAQ standards • Airborne particle distribution in dictated by physics • Resultant mass distribution • Theoretical distribution based on physics *Source US EPA Website
Future Changes to Standards • Discharge adjusted efficiency for each particle range is cross multiplied by standardized PM2.5 curve and PM10-2.5 Curve • KEY POINTS • Final Filter Efficiency Would be Reported for PM2.5 and PM10-2.5 as a % X PM2.5 = 92% PM10-2.5 = 99%
We provide superior filtration solutions to improve the quality of life Filtration Standards Presentation Dan Woodman April 23, 2010