Measurement and evaluation of the optical radiation of various stage floodlights with regard to the damage to the eye and skin (BoSS)

Status:

completed 10/2021

Aims:

On stages and in studios, stage floodlights are used to illuminate even people. With the advent of LED technology in the last decade, the optical radiation of stage floodlights has changed by orders of magnitude in terms of spectral distribution, source size and power density. For many users and the responsible accident insurance institution, it is unclear how high the danger from optical radiation is and what protective measures should be recommended.

The aim of the research project "FP 420 BoSS - Measurement and evaluation of stage luminaires in terms of damage to the eye and skin" was to measure 40 stage luminaires in terms of their optical radiation hazard. Technological advances such as the new LED technology or the new discharge lamps of the UHP (Ultra High Pressure) type motivate the present work.

Activities/Methods:

The biologically motivated measured quantities (weighted irradiances and radiances) relevant for the assessment of the hazard have been determined, such as the hazard due to actinic UV, the UV-A damage to the eye lens, the photochemical and the thermal retinal damage LB and LR as well as other quantities as defined in DIN EN 62471. The weighted irradiances have been determined using two synchronously deployed spectrometers from Instrument Systems covering a wavelength range from 200 to 1665nm. The integral measurement system from Gigahertz-Optik (LDM-9811) has been used to measure the weighted radiances. Measurements are made at distances of 20 cm, 50 cm, 1 m, 2 m, 4 m, and 8 m. It proved useful to classify stage lights based on their light sources: LEDs, discharge lamps (CDM, HMI, HMI SA and UHP) and semiconductor lasers.

Results:

The extensive measurement results for the individual stage spotlights have been compressed in the form of fact sheets, which, in addition to the spectrum and other measured quantities, also contain a hazard level in 4 meters (RG4m) defined by us, as well as the maximum exposure time.

Overall, the results can be summarized as follows:

• If we consider the weighted radiances LB and LR, the stage radiators with UHP lamps and lasers are particularly dangerous. They belong to RG4m=3.
• The remaining stage spotlights with LED, CDM, HMI and HMI SA burners mostly belong to RG4m=2.
• Overall, there is a ranking in the dangerousness of the stage lamps UHP "approximately equal" laser > HMI SA > HMI "approximately equal" LED > CDM.
• With the help of empirical rules, the hazard potential can usually already be estimated with the help of the data sheets of the stage lamps.
• For the UV range, there are isolated hazards in the stage floodlights with UHP and HMI light sources, but these could be easily eliminated technologically.

See also the overview figure in report.

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