1. NAFA Technical Seminar April 19, 2012 ANSI/ASHRAE 52.2 Can we fix this Method of Test?

2. History of the Test procedure 10+ years in development prior to 1999 release Task of 52.2 Committee "create a test method based on particle size removal efficiency for end user evaluation of filter performance" Research projects led to greater understanding of the physical science in filtration MERV - scales were created with minimal data and educated guesses at value spread

4. Committee Efforts Std published in 1999 for the first usage No revisions through 2007 (other than edits) 2008 Arrestance and DHC were added from 52.1 predominantly for MERVs 1-4 52.1 was removed from ASHRAE Standards Addition of "Voluntary Conditioning Step"

5. MERV's Status? ASHRAE Rating system? No certification of personnel performing tests No policing entity to produce a rating system

7. ISO Standards Working groups creating standards for Cleanroom and HEPA usage completed UVC, Rotating Equipment, dust collection Working group 3 - General HVAC filtration is looking to use 52.2 MOT for developing PM efficiency values

8. Definition: System of classification according to merit or amount Assessment of something in terms of quality, quantity or both What filter parameters should be included?  Filter Performance – pressure drop, efficiency, life  Energy  Perceive Value  Cost Filter Rating

9.  Is it possible to combine filter performance characteristics into one criterion?  Greater value of the criterion equal to “better” filter  Traditional quality factor (figure of merit): o E – filter efficiency and ΔP o – filter pressure drop  Potential issues:  Different ΔP o units  Results at different flow rate Filter Rating

10.  Example 1: E1 = 80% and ΔP o = 0.40” H 2 O α1 = - ln (1 – 0.8)/ 0.40 = 1.609/0.40 = 4.02  Example 2: E1 = 80% and ΔP o = 0.30” H 2 O α2 = - ln (1 – 0.8)/ 0.30 = 1.609/0.30 = 5.36  Example 3: E1 = 85% and ΔP o = 0.40” H 2 O α2 = - ln (1 – 0.85)/ 0.40 = 1.897/0.40 = 4.74 Filter Rating

11.  Single Aggregate Objective Function (AOF)  Weighting method, linear AOF: MAX o E – filter efficiency; ΔP o – filter pressure drop o C – filter cost; DHC – filter dust holding capacity o λ – weighting factors; ∑ λ i = λ 1 + λ 2 + λ 3 + λ 4 =1 o λ – weighting factors are assigned based on priority - subjective Filter Rating

12.  Combination of objectives:  Other objectives: Cost, Energy Filter Rating

13.  MERV – is MERV a rating system?  Residential filters – Home Depot  FPR (Filter Performance Rating) = 1 – 10 scale Weighted Average = λ 1 (Efficiency Large Particles) + λ 2 (Efficiency Small Particles) + λ 3 DHC λ 1 + λ 2 + λ 3 = 0.6 + 0.3 + 0.1 =1  FPR = 10 for Weighted Average > 25  Residential filters – 3M  MPR – Microparticle Performance Rating ability to capture particles 0.3 – 10 µm (E1) Filter Rating - Examples

14. “Too Many MERV’s” ?? According to ASHRAE and IEST – 20 Possible Assignable MERV’s Three “Markets” E3 Arrestance MERV 1-4 General Equipment E2 Middle Efficiency MERV 5-12 Equipment and People E1 High Efficiency MERV 13-20 Marginalized Health People and Specialized End Uses Real Differences Between the Markets Arrestance High Efficiency Real Differences Within These Markets MERV 5 MERV12 Difficulties Variety of End Uses Variety of Air Handling Types Variety of Pollutants

15. Conditioning Step is Too Expensive The equipment to do the test is expensiveOnly a few third party labs do the test The test is repeated until equilibrium, often many times 15

16. Conditioning Step Not Real World “Conditioning” does not emulate real filtration conditions Pre-loading of only nano- particles is unrealistic By definition, conditioned filters are tested pre-loaded with dust 16 Mechano-Electret Filter Mechanical Only Filter

17. 52.2 Positive Attributes before Conditioning 52.2 Relatively cost effective One step--it is what it is ANSI Certified Controlled Lab Conditions 17

18. Analogy—Gas Mileage Testing EPA City/Highway 26/37 mpg Car and Driver Observed 21 mpg EPA to go to full throttle testing to get the true minimum? http://www.caranddriver.com/reviews/2012-ford-focus-sel-test-review 18

19. ASHRAE 52.2-2007 Tom Justice

20. 2010 Round Robin

21. 2011 Round Robin

22. Issues under Review by Task Groups Current MERV boundaries Humidity Range OPC particle counter specifications Air density calculation Shedding IPA vapor conditioning Test variability

23. Reported Values Channel E1E2E3 Reporting Value Particle Size Range.3 to 11 to 33 to 10 Filter 1 37%65%84%MERV 8 Filter 2 36%65%85%MERV 11

31. Issues under Review by Task Groups Current MERV boundaries Humidity Range OPC particle counter specifications Air density calculation Shedding IPA vapor conditioning Test variability

32. Fig. 8 ASHRAE 1287 RP

33. KCL @ 0% to 85% RH

34. Other Potential Issues Test dust Specifications for particle generator Radioactive versus corona discharge in neutralization of airstream Initial resistance calibration