ABSTRACT
INTRODUCTION Ultraviolet (UV) disinfection of water is a growing technology, but accurate measurement of the UV output of a UV lamp remains a challenge. Measurements often vary widely from one lab to another, leading to uncertainty and mistrust of UV-output claims in the industry. Sources of error abound: some error is sure to be present in any measurement of UV irradiance, and some error is likely to arise in the calculation of total UV output from underlying irradiance measurements-even if the irradiance measurements are considered accurate-because the measurements are taken at only a finite number of positions around the test lamp, or because inappropriate assumptions are used in the calculation. We have made much effort trying to find and reduce errors in our own UV-lamp-measurement lab. Some of our findings are presented here. We hope that our experiences may be helpful to others in their attempts at accurate measurement of UV-lamp output.
