Air Filtration and Indoor Air Quality Panel Discussion Moderator: Jim Rosenthal, CAFS Panelists: Bobby Singer, Blue Heaven Technologies, CAFS John Zhang, 3M Company Michael Waring, PhD, Drexel University

Filter Testing Using the ASHRAE 52.2 Protocol Bobby Singer, CAFS Blue Heaven Technologies Copyright © 2016 3M

Current Document

ASHRAE 52.2 Metrics for laboratory comparisons ….. 1/28/2018 3:32 AM ASHRAE 52.2 Metrics for laboratory comparisons ….. Resistance to Air Flow – “w.g. Efficiency by Particle Size - % .3 to 10 Microns 12 “bands” to construct “MERV” Arrestance of loading dust - % Dust Holding Capacity - grams To a prescribed final resistance © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

Overview understanding the objective ….. Specific to Air Filter Performance Benchmarking Controlled environment “Perfect” conditions NOT a direct predictor of IAQ

Typical Report Page 1 E1, E2 and E3 Flow Rate Clean Resistance Final Resistance MERV

Typical Report Page 2 “RT” Curve Six efficiencies “Composite”

Typical Report Page 3 All tabular “RT” at Flow Rate Composite Min. !

Typical Empty Duct Correlation

System Qualifications – “What” A Key to Proper Testing

Courtesy – Mike Corbat, Custom Filter - 2015 AFS

Ambient Conditions – New! A Key to Proper Testing

From the horses mouth…… Standard 52.2 was developed so that both users and specifiers can compare products, predict a uniform level of known performance under operating conditions with reason- able certainty, and determine appropriate air-cleaner efficiencies for specific situations. Not an Application Standard Users should not misinterpret the intent of this standard. This is a test method standard, and its results are to be used to directly compare air cleaners on a standardized basis irre- spective of their applications 1. PURPOSE This standard establishes a test procedure for evaluating the performance of air-cleaning devices as a function of particle size.

So Many Questions Bobby Singer Blue Heaven Technologies 502-357-0132 bobby@blueheaventech.com

Air Filtration and Indoor Air Quality Panel Discussion John Zhang, Ph. D 3M Company Copyright © 2016 3M

Impact of Filtration on Indoor Air Outline Indoor Particulates Micro-particle Filtration Performance of Residential HVAC Filters Impact of Filtration on Indoor Air Quality 3M Copyright 2016

10 mg/m3 increase => 0.35 years reduction in life expectancy Indoor PM2.5 Pollution PM2.5 pollution 10 mg/m3 increase => 0.35 years reduction in life expectancy 3M Copyright 2016

Why MPR (Micro-Particle Rating) Ignored for MERV 12 or less MPR is a rating system for filters performance in the micro-particle size range (particle size < 1 micron). 99% of respirable particles (smoke, aerosol, bacteria, virus, allergens, fine dust) are smaller than 1mm. Micro-particles have significant adverse health impact. Filter efficiency for micro-particles (<1 micron) is excluded in the MERV rating for MERV 12 or lower filters. 3M Copyright 2016

Filter Performance 3M Copyright 2016 Particle Size, µm 0.001 0.01 0.1 1.0 10 100 Tobacco Smoke Bacteria Virus Pollens Fungi Oil Smoke Pet dander Human Hair Visible Invisible PM2.5 Dust mite allergens Household dust Human Hair: > 60 mm Pollens: 0.8 – 40 mm Pet dander: 0.5 –10 mm Dust mite allergens : 0.8 – 40 mm Household dust: 0.1 – 10 mm Fungi: 0.5 – 5 mm Bacteria: 0.3 – 10 mm Cooking smoke: 0.05 – 1 mm Tobacco smoke: 0.01 – 1 mm Virus: 0.003 – 0.1 mm 2.5 3M Copyright 2016

Effectiveness of Air Filters CONTAM IAQ model developed by NIST, considering factors such as: Filter performance Ambient aerosol concentration Building structure, infiltration etc Indoor particle sources and sinks Summary Indoor airborne particulates are mostly micro-particles (<1 microns) Filters can effectively reduce indoor airborne particles. The reduction is governed by filter performance in the micro-particle size range. 3M Copyright 2016

John Zhang 3M Company zzhang2@mmm.com Panelist Contact Information John Zhang 3M Company zzhang2@mmm.com 3M Copyright 2016

Air Filtration and Indoor Air Quality Panel Discussion Michael S. Waring Associate Professor Director of Architectural Engineering Civil, Architectural and Environmental Engineering at Drexel University Copyright © 2016 NAFA

How effective are filters? We know that filters CAN remove PM efficiently… ASHRAE 52.2 tests PM > 0.3 μm Ultrafine PM (< 0.1 μm) is removed well by some filters However, efficiency does not indicated how effective filters are at removing PM indoors Function of building and climate Hecker and Hofacre (2008)

What are the driving factors? Building and climate can impact effectiveness due to: HVAC airflow paths (residential or commercial) Impacts size of particles contacting filter Impacts amount of outdoor versus recirculated air HVAC runtime (residential or commercial) Residential HVAC operation on duty cycle dictated by loads Commercial HVAC operation is largely continuous Filter installation goodness Potential for HVAC filter airflow bypass

Residential vs. commercial airflows Waring & Siegel (2008)

Size of particles contacting filter Office PM distributions Residential PM distributions Mass Conc. Mass Conc. PM2.5 PM10 PM2.5 PM10 Riley et al. (2002)

Office and residential AERs recirculation Infiltration AER Office: 0.35 h-1 (2.1) Res: 0.44 h-1 (2.04) Ventilation AER Office: 1.13 h-1 (2.59) Res: 0 h-1 Recirculation AER Office: 3.25 h-1 (2.2) Res: 1.4 h-1 (1.9) = 5.7 h-1 (1.3) × 0.25 (1.9) O ventilation R O infiltration O R Chan (2006); Rackes and Waring (2013, 2015); El Orch et al. (2014)

Understanding parameter impacts PM2.5 I/O ratio can show impacts of filter efficiency: penetration factor = 0.9 infiltration AER (O & R) filter efficiency from 0.1 to 0.9 ventilation AER (O only) deposition rate = 0.1 h-1 infiltration AER (O & R) ventilation AER (O only) filter efficiency from 0.1 to 0.9 recirculation AER (O & R)

Understanding parameter impacts 10,000 iterations were run to compute I/O ratios Regressions w/ standardized regression coefficients (SRC) SRCs are coefficients standardized so that the variances of dependent and independent variables are 1 – show influence of inputs

Panelist Contact Information Michael S. Waring Civil, Architectural and Environmental Engineering at Drexel University msw59@drexel.edu