Projects concerning artificial incoherent optical radiation

During the performance of stage productions, actors and the stage as a whole are illuminated by means of stage lights. High-power lights may be used for this purpose, in some cases taking the form of spotlights aimed directly at the actors and tracking them. Besides visible light, stage lights also generate a potentially hazardous ultraviolet (UV) radiation component. The exposure to blue light must also be assessed. Stage light configurations in theatres differ according to the size of the stage and also the type of production being performed. A range of lighting situations and tests also arise during normal rehearsals. The exposure limits for protection against UV radiation were found to be observed; however, a new method must be developed for assessment of the exposure to blue light. The methods used in the past have been found to be unsuitable when multiple stage lights are used, since targeting such multiple light sources has proved impossible, for geometric reasons.

Project page of IFA project 4218

A number of different welding methods are in use and are selected according to the application. These methods range from oxyfuel gas welding to stick electrode welding and new, pulsed methods such as cold metal transfer (CMT). Whereas arc welding methods have been studied relatively comprehensively, data for oxyfuel gas and pulsed welding methods is still lacking. Study of the oxyfuel gas welding methods showed UV radiation exposure to be a result of the gas combustion, and that shading by the workpiece reduced the exposure. The results of IFA Project 4144: Emissions of optical radiation during the treatment of glass workpieces by means of gas torches can be transferred directly. The results of the measurements conducted during the use of the new CMT method revealed no systematic increase or decrease in irradiation values attributable to its use. Considerable differences in values were observed between welding methods used (e.g. metal active gas (MAG) or tungsten inert gas (TIG) welding).

Project page of IFA project 4210

UV exposure of welders and their assistants is substantially dependent upon the radiation emitted by the welding arc. Considerable exposure may however arise from reflections as well as from direct radiation. It is therefore not sufficient for protection to be provided against direct radiation alone during welding work. In addition, welders’ assistants are often significantly less well protected than the welders themselves. The aim of the project was to study the reflection of UV radiation on a range of surfaces. Overall, reflection was found to be in the order of 0.2% to 1.2%. A relationship was demonstrated between the reflected radiation components and the reflecting surface. Both the material of the surface and its colour were factors here. Some surfaces (such as a fire blanket and highly reflective Silverice plates) exhibited increasing reflection with rising wavelength, whereas no relationship between wavelength and reflection was observed for the standard welding curtains.

Project page of IFA project 4209

Gas torches are frequently used in glasswork for the heating of glass workpieces. The gas flame of these torches emits radiation in the optical (ultraviolet, visible and infrared) wavelength range to which the workers may be exposed. The results of the project have been described comprehensively in an IFA Report.

Project page of IFA project 4144