Kathleen Owen, ASHRAE Fellow, has extensive experience in gaseous and particulate matter air cleaning, determining air cleaning efficiency, and developing test methods to evaluate various air cleaning technologies.
Prior to starting her own company, Kathleen spent 33 years at RTI International where she worked on the ASHRAE and EPA projects that developed ASHRAE air cleaner efficiency test methods 52.2 (for particles), 145.2 (gases), and 185.1 (UV-bioaerosol). She also developed chamber test methods for gas and bioaerosol removal by in-room air cleaners based, in large part, on the AHAM CADR test method. One early project she ran was the first published measurements of indoor air particle sizes based on HVAC settings and building sources. Her ~1990 particle size literature search led to a table of particle size ranges, published in Atmospheric Environment, that has been cited often and is used in the ASHRAE Handbook. EPA, DOD, ASHRAE and other projects she has worked on included air cleaning, air quality, contaminant transport modelling, technology development, and aerosol penetration of protective garments. Also, after working in the lab for several years, she ran the RTI commercial air cleaner test lab for over 20 years with over 100 different companies as customers over the years. She now works for various customers as a consultant.
Kathleen has served ASHRAE in a variety of capacities. She is currently the PI on 1720-RP “Validation of gas-phase air-cleaner performance test method (Standard 145.2) by laboratory testing of commercially available filtration devices” and of 1784-RP “Repeatability and reproducibility assessment of ASHRAE Standard 52.2 as currently amended.” She is the co-PI on ASHRAE project 1838-RP “Emerging gas-phase electronic filtration technologies and ASHRAE 145.2 test standard” which is exploring how reactive air cleaners (RAC) work and what they emit to be able to update the test standard to include the needed byproduct analysis.
Currently a member of the Epidemic Task Force (ETF), she serves on many ASHRAE committees. She was the first chair of ASHRAE committee SSPC 145, is the immediate past chair of ASHRAE 52.2, and is the Vice Chair of ASHRAE TG2.RAST Reactive Air and Surface Treatment. She was the research subcommittee chair for TC2.3 Gaseous Contaminants for 10 years and is an incoming member of Standards. She is also working with AHAM in the development of their new bioaerosol and gas-phase air cleaner test methods.
Kathleen earned a BS in chemical engineering from NCSU and an MS in Air Pollution Control Engineering from UNC-CH.
Particle air filters are designed to collect dust as they are used. It has long been understood that this use changes the efficiency and pressure drop for the filters over time. However, there has been little carefully-collected, publicly-available data on these changes. While the collected dust may be readily visible, the efficiency and pressure drop require equipment to measure. For repeatable measurements laboratory data collected under controlled conditions are usually needed. This presentation is based on the results of ASHRAE project 1360-RP. Uncharged MERV 7 and charged MERV 11 residential filters and uncharged MERV 15 commercial filters (uncharged MERV 15) were installed in cites in four cities then returned at prescribed time intervals for laboratory testing to determine efficiency, weight gain and pressure drop. Standard ASHRAE 52.2 tests were also run. Thus, real-world use was compared to test results.
The results showed that after use, a filter’s efficiency may increase or decrease depending on the type of filter and the nature of the exposure. Overall, the changes in efficiency with time are not well represented by the dust-loading steps in the ASHRAE 52.2 test. Appendix J conditioning was needed to bracket the minimum in-situ efficiency of the charged filter, and filters did not reach efficiency levels as high as those obtained after the final dust loading step. Reporting values calculated from the minimum efficiency curve were much more indicative of in-situ performance than those based on the average or final dust-loaded efficiency values. Weight gain vs. pressure drop did not show good correlation with the ASHRAE 52.2 tests for the two higher efficiency filters. Also, typically-quoted service lives were too short; filters in use are not likely to reach the pressure drop recommendations if their use is determined by a time schedule.
Filters do change significantly with use in both expected and surprising ways. ASHRAE 52.2 testing, especially with Appendix J conditioning, can provide useful information about the change in performance of filters over their lifetimes.