Absorbing harmful wavelengths of visible light emitted by a welding torch through tue use of a yellow filter: experimental evidence.

Abstract

PURPOSE: This study was designed to determine the emission spectrum of a professional welding torch and quantify the absorption of several wavelengths of visible light by yellow filters of different optical densities. METHODS: Three measurements of the emission spectrum of a welding torch were made at 3 distances between 20 to 40cm. Subsequent to this, 6 layers of e-colour-10 yellow filters supplied by Rosco were placed in front of the torch and the transmittances determined of all the light bands emitted by the torch crossing the filter. RESULTS: The measurements obtained were: for 370nm, the torch emitted 680 relative units (RU) of which the filter absorbed 6440 RU (94%); for 415nm emission was 350 RU and absorption by the filter was 100%, for 430nm, amission was 700 RU and absoption 600 RU ( 96%); for 450nm, emission was 270 RU and absorption 100%; for 450, 480nm amission was 350 RU and absortion 300 RU (85%) and for 490nm, amission dropped from 200 RU to 60 RU (70%) CONCLUSIONS: In relative units, the emission of short wavelengths (violet-blue light) by a elding torch is high. A yello filter practically eliminates all the harmful bands of the visible spectrum. The use of these filters to protect the retina is recommended for professional welders.