March 14, 2003—The Air-Conditioning & Refrigeration Technology Institute (ARTI) has released a study entitled, “Defining the Effectiveness of UV Lamps Installed in Circulating Air Ductwork”. The results of this research on laboratory testing of germicidal ultraviolet (UVGI) lamp efficacy to inactivate representative environmental microbial aerosols in ventilation ducts provides information to designers, practitioners and forensic scientists.
Germicidal ultraviolet (UVGI) lamps have a long history of use for inactivating microbial aerosols and most research has focused on the control of infectious diseases, such as tuberculosis in medical facilities. The rise in Indoor Environmental Quality (IEQ) problems has resulted in increased use of UVGI lamps in ventilation ducts. These in-duct applications are generally concerned with controlling environmental organisms.
UVGI lamps were experimentally demonstrated to inactivate bioaerosols composed of vegetative bacteria, bacteria spores, or fungal spores to a reproducible degree under conditions of fixed dose. Vegetative bacteria were most susceptible to UVGI, with bacteria and fungal spores being substantially more resistant.
The key factors for the design of in-duct UVGI systems intended to disinfect moving airstreams were determined to be: (1) UV lamp irradiance at operating conditions, (2) microbial resistance data, (3) having a tested and functioning bioaerosol dose model, and (4) duct wall reflectance. Given this information, UVGI system designers can make reasonable and responsible performance estimates for most in-duct applications.
UVGI is a low-pressure-drop, nonintrusive technology that has real potential. ARTI recommends, as a result of this research, that test methods and guidance for performance claims regarding bioaerosol and bioterrorism agents be developed by an experienced and broadly based group of technical experts, users, and manufacturers.
Until rigorous and adequate tests have been developed and performed, claims regarding protection against aerosol bioterrorism agents are suspect. ARTI will be working with the appropriate federal agencies to encourage further the development of a complete empirical database of UVGI effectiveness.
The final report can be downloaded from ARTI.
