Use of Filtration to Reduce Air Change Rates and Improve Ventilation Effectiveness

Thomas Smith, Exposure Control Technologies, Inc.
Kenneth Crooks, Erlab, Inc.

People working in laboratories are potentially exposed to airborne contaminants generated during laboratory scale procedures. Ventilation systems are required to minimize exposure to hazardous airborne contaminants and provide comfortable working conditions. However, laboratory ventilation systems are expensive to build and to operate due to high airflow rates and inability to recirculate potentially hazardous materials. Criteria for laboratory airflow rates are generally expressed as air changes per hour (ACH) and based on exhaust of one pass air through the lab. The desire to minimize airflow has placed pressure on laboratory managers to justify and reduce laboratory airflow rates. New technology has been developed to remove contaminants typically found in laboratories while simultaneously improving airflow distribution and ventilation effectiveness. The technology can be installed in laboratories to improve lab safety, reduce ACH, reduce energy consumption and improve ventilation effectiveness. This paper describes the technology and provides data from experimental studies demonstrating the impact on ventilation effectiveness in laboratories over a range of air change rates.

Learning Objectives

  • Recognize system designs that improve ventilation effectiveness and occupant safety.
  • Recognize conditions that allow for a safe reduction of air change rates in laboratories, and those conditions that do not.
  • Achieve energy reduction goals while simultaneously improving airflow distribution and ventilation effectiveness.
  • Reduce occupant exposure to hazardous chemical vapors through filtration of the lab air.


Thomas C. Smith is the President of Exposure Control Technologies, Inc. Mr. Smith is a leader in safety and energy management for research facilities. He specializes in helping laboratories provide safe, dependable and energy efficient operation of laboratory hoods and ventilation systems. He holds a BS degree in Mechanical Engineering from North Carolina State University and a MS degree in Environmental Engineering (Industrial Hygiene) from the University of North Carolina.

Ken Crooks has over 25 years of experience in commercial and industrial HVAC industries. He is Director of GreenFumeHood Technology at Erlab in Rowley, MA which produces world-leading research-grade filtering technologies for fume hoods and laboratories. Previously, Mr. Crooks worked at Phoenix Controls, Aircuity and Munters Corporation. Mr. Crooks is a member of ASHRAE, NFPA, I2SL and SCUP, and his education includes Northeastern and Lesley University.


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