Guest blog by Kathleen Owen, ASHRAE Fellow, ETF member and Air Pollution Control Engineer for Owen Air Filtration Consulting

Have you been asked how MERV filters catch PM2.5?  Obviously, it’s easy to go to the ASHRAE Standard 52.2 MERV table and see that a MERV 13 filter is ≥ 85% in the 1-3 µm particle diameter size range.  This is often the answer you need.  Still the questions keep coming, including from ASHRAE SSPCs 62.1 and 62.2.  With ISO 16890 providing an ePM and these ASHRAE committees deciding to specify filters using particulate matter efficiencies, it became clear that ASHRAE 52.2 needed to address this issue.

Surgical masks and respirators are typically made of nonwoven polypropylene fabric and mostly consist of three (or more) layers. The first and third layers are generally spunbond, while the middle layer is meltblown. This composition is commonly referred to as SMS technology (Spunbond/Meltblown/Spunbond).

While the efficiency of face masks is measured by norms defined by ASTM or NIOSH, producers of nonwoven materials need to have insight into the pore size of their material as well.

This document briefly explains how the pore size distribution of these nonwoven materials can be measured using a gas liquid porometer with the ‘pressure scan’ method.

The August meeting of the Southwest Chapter of the American Filtration & Separations Society was held Tuesday, August 11, on the topic of Asymmetrical Cake Filtration on Tubular Elements and the Effects on Scalability. Bradley Moakler, North American Regional Manager for DrM Inc., presented.

Proper design of a solid-liquid tubular element filter requires a thorough understanding of all variables within a process. Most small-scale filtration studies are performed with either a downward flow nutsche pressure filter or vacuum filter due to simplicity and overall space and batch requirements. Although this may produce successful results in terms of quality and throughput, several other factors such as cake homogeneity, particle sedimentation, and cake discharge cannot be effectively assessed which can present inaccuracies in sizing and operating a commercial tubular element filter. This presentation examines the inaccuracies that can develop upon scaling to a tubular element filter.

Bradley Moakler holds a B.S. in Chemical Engineering from the University of Nevada, Reno. After graduating, he worked as a process engineer for three years in the separations circuit at Molycorp, a rare earth mineral processing mine. He is currently working as North American Regional Manager for DrM Inc., a subsidiary of DrM, Dr. Mueller AG Switzerland, and has been with the company for approximately five years. His work mainly involves sales engineering, process development, and business development.

When you join AFS, you’ve taken only the first step to realizing value from aligning with the nation’s foremost association for filtration professionals. Members receive discounts on virtual courses and conferences, access to exceptional continuing education and networking opportunities, and free attendance at all AFS chapter meetings. These are all great reasons to join AFS, but people who get the most from their AFS memberships are those who join a committee and start forming long-lasting bonds with other AFS members.

The following active AFS committees and their respective chairs are currently seeking new volunteers:

• Articles and By-Laws – Chair, Jim Walker
  • Shall ensure that the Articles and By-laws of the Society are consistent with the purpose and needs of the Society.
• Chapter Affairs – Chair, Wenping Li
  • Shall represent the local chapters at the National Board of Directors meetings and organize, coordinate and implement with the local chapter’s programs to support their activities and growth. The Committee will annually prepare a listing of National Board of Directors members and assign them each to a local chapter closest to their region to reinforce the support of National AFS at a local level.
• Finance Committee – Chair, Jim Walker
  • Shall recommend financial policies, annually audit the financial transactions, shall arrange for and have conducted an external audit, and shall assist the Treasurer in long-range planning.
• Marketing and Communications – Chair, Felicia Littlejohn
  • The Marketing and Communications Committee is responsible for content made public by the AFS. In addition, this committee creatively promotes the Society, its conferences and initiatives, promotes AFS to the general public and industry professionals, creates videos, posts to social media, and conducts interviews and surveys to collect feedback from current and potential members.
• Membership – Chair, John Hancock
  • Shall conduct programs directed toward recruiting new individual members and effectuating membership renewal. The Committee shall also recruit and support active participation by leading companies in the field of filtration and separations.  This committee shall act as the interface between the Corporate Sponsors and the Society.
• Publications – Chair, Bharath Raghavan
  • Shall maintain and update the master calendar, shall publish a newsletter containing, among other subjects, Chapter and industry information, and shall seek a new journal partnership.
• Users Committee – Chair, Andrew Goodby
  • Shall encourage the participation of filtration and separations end users in Society functions and advise the AFS Board of Directors in developing programs to increase the activity and membership of vendors and end-users. This Committee shall also conduct and annual New Product/Engineering Merit competition and recognition program for Corporate Sponsors of the Society.  This Committee shall also administer the AFS “Uncle” program for the local chapters to present papers, market AFS and recruit new members for the Chapters and Society.

To volunteer for a committee, please email Lyn Sholl, Executive Director