Spatial distribution of fluence rate from upper-room ultraviolet germicidal irradiation: Experimental validation of a computer-aided design tool

Abstract

A commercial computer-aided design tool used by the lighting industry was modified to predict fluence rates for upper-room ultraviolet germicidal irradiation. Experimental validation based on more than 1600 measurements and 3 types of commercial ultraviolet fixtures, which was done in an experimental chamber and in a homeless shelter having fixtures in continuous use for over 7 years, showed differences in measured and predicted average upper-room fluence rates of less than 10%. The computer-aided design tool, however, was not very successful at predicting fluence rates at specific room locations, a capability that is needed for mating computational fluid dynamics with ultraviolet germicidal irradiation. Although not an objective of this study, it was also found that the three types of fixtures used in this study have surprisingly significant differences in efficiency based on fixture ultraviolet power output and electrical input. One fixture type had an efficiency that was more than five times that of another. For comparison purposes, a standard method for measuring and reporting fixture efficiency is needed.

Acknowledgments

The authors thank the New York State Energy Research and Development Authority (NYSERDA) for supporting this work (Project 9450). Thanks also go to David DiLaura for his help in modifying the Visual program for UVGI and the committee that helped plan this research project, which, in addition to the authors, included Robert Angelo, Hilary Boehme, William Chaisson, Charles Dunn, Jr., Randall King, and Paul Minor.

Stephen N. Rudnick, DSc, CIH, is Lecturer on Industrial Hygiene Engineering. Melvin W. First, DSc, PE, CIH, is Professor of Environmental Health Engineering, Emeritus. Tim Sears, MIES, is Senior Illuminating Engineer. Richard L. Vincent, FIES, LEED-AP, ASHRAE Member, is Administrative Manager. Philip W. Brickner, MD, is Director of Tuberculosis Studies. Peter Y. Ngai, PE, FIES, LC, is Vice President of Research and Development. John Zhang, MIES, LC. Robert E. Levin, PhD, is Corporate Scientist (Retired). Kenneth Chin is Medical Student. Ronald O. Rahn, PhD, is Adjunct Professor of Environmental Health Science. Shelly L. Miller, PhD, is Associate Professor. Edward A. Nardell, MD, is Associate Professor.