Optimizing Air Change Rates for Laboratories

Tom Smith, Exposure Control Technologies

People who work in research laboratories are potentially exposed to many hazards including airborne contaminants generated from processes involving chemical, biological and radioactive materials.  Ventilation systems are required to minimize exposure to hazardous airborne contaminants and provide comfortable working conditions.  However, laboratory ventilation systems are expensive to operate with the supply and exhaust of conditioned air being the largest consumer of energy in a laboratory building.  The desire to minimize airflow has placed pressure on laboratory managers to justify and reduce laboratory airflow rates.  Criteria for laboratory airflow rates are generally expressed as air changes per hour (ACH) with typically recommended rates ranging from 4 ACH to 15 ACH depending on the type of laboratory or operating mode.  However, specification of a prescriptive ACH may lead to a false presumption of safety.  This paper describes use of a process to derive the minimum ACH required for a laboratory and explores techniques to lower ACH, improve capture of airborne hazards and operate safer and more energy efficient laboratories.

Biography:

Mr. Tom Smith is a leader in lab safety and energy management. 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 from the University of North Carolina. Mr. Smith is active in developing national and international standards for lab ventilation and has served as Chairman of ASHRAE TC9.10 Laboratory Systems, Vice Chairman of ANSI/ASHRAE 110 Fume Hood Testing, and is the Vice Chairman of ANSI/AIHA Z9 Standards for Ventilation and Health. Since 1985, Mr. Smith has participated in hundreds of laboratory ventilation projects and evaluated thousands of laboratory hood systems. His work has helped improve the safety of lab environments, reduced energy consumption and saved millions of dollars in operating costs.

 

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