Erythemally effective and actinic irradiance from a tungsten halogen lamp.

A protocol for assessment of biological hazard from ultraviolet radiation sources was developed. The protocol utilized both a ultraviolet radiation spectroradiometer and a broadband ultraviolet radiation meter for the determination of the erythemally effective irradiance and the actinic irradiance. A 250 W tungsten halogen lamp operating at 9.5 A was tested with this protocol. It was found that the erythemally effective irradiance varied from 41 microW cm(-2) at 10 cm to 1.5 microW cm(-2) at 50 cm. In the same range of distances, the actinic irradiance decreased from 23 to 0.5 microW cm(-2). The irradiance from the source was uniform within 30 degrees about the line perpendicular to the axis of the filament. Using the recommendation of the Australian radiation protection agency, the National Health and Medical Research Council, the maximum allowable exposure time at the distance of 50 cm in the direction perpendicular to the axis of the filament was about 33.3 minutes.