ASHRAE/TSHE/AIA Cincinnati October 2025 Lunch Technical Session

Basics of Air Change Rates: Facts versus Fiction - Kishor Khankari, Ph.D., Fellow ASHRAE

Basics of Air Change Rates (ACH): Facts versus Fiction (AIA and GBCI approved)Air Changes per Hour (ACH) is often specified in ASHRAE standards, codes, design guidelines, and handbooks for required ventilation rate. Examples of such spaces are patient rooms, operating room, bathrooms, cleanroom, and laboratories. This presentation will systematically demonstrate the validity of popular notions regarding the ACH. The role of space volume in controlling and distributing the contaminant in the space will be discussed. This presentation will further demonstrate whether ACH can’t be a sole criterion for effective ventilation of critical spaces using the examples for patient room, hospital operating room, laboratory spaces, and cleanroom. A new concept for analyzing ventilation effectiveness for these spaces will be introduced to design and optimize the HVAC layout for healthcare, laboratory, and cleanroom facilities. In addition, a role of demand control ventilation in minimizing the ACH will be discussed. This lecture will provide valuable insights to architects, design engineers, and facilities managers into the design and operation of critical facilities.

Dr. Kishor Khankari, Ph.D. is President at AnSight LLC in Ann Arbor, MI. He provides engineering solutions and insights through Physics based simulations and CFD analysis. Kishor has several years of experience in providing optimized HVAC solutions to a wide variety of applications involving external wind engineering, plume dispersion, smoke exhaust, displacement ventilation, natural ventilation, radiant heating and cooling, and indoor air quality and thermal comfort optimization for office spaces, patient rooms, operating rooms, cleanrooms, justice facilities, data centers, and warehouses. Dr. Khankari has developed a patented technology of a wind band design of exhaust fan assembly systems. He has developed several easy-to-use analytical software tools which are regularly used by design engineers in a variety companies including those in HVAC industry, critical facilities, and automotive industries. A noted expert in his field, he has a Ph.D. from the University of Minnesota and has been regularly published in several technical journals and trade magazines. Dr. Khankari has delivered more than 150 DL presentations worldwide on topics related to design and optimization of HVAC systems and made several presentation at various technical conferences and professional meetings. Dr. Kishor Khankari is a Fellow member of ASHRAE. He served on ASHRAE Board as a Director-at Large. He is a recipient of Louise & Bill Holladay Distinguished Fellow Award, ASHRAE Exceptional and Distinguished Service Awards. He is the past President of Detroit ASHRAE Chapter, past Chair of ASHRAE Technical Committee TC9.11 Clean Spaces, and past Chair of Research Administration Committee (RAC). He is a voting member of Technical Committee TC9.10 Laboratory Systems and TC5.3 Air Distribution. He is a voting member of Standards committees SPC241: Control of Infectious Aerosols and SPC129: Air Change Effectiveness. He is also leading a Multi Task Group (MTG) on Air Change Rates.

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