The intensity and spectral distribution of ultraviolet emission from welding arcs in relation to the photo decomposition of gases

Abstraet--The intensity and spectral distribution of the ultraviolet emission from arcs produced during the welding of cast iron, stainless steel, aluminium and copper, both with covered electrodes andwith inert gas shields, llave been measured. Froma knowledge of the relevant parameters, the extent of photochemical breakdown corresponding t the measured intensity of emission over each wavelength interval may be calculated. By this means the photodecomposition of trichloroethylene to phosgene and dichloroacetyl chloride has been calculated; the results obtained ate of the same order as the concentrations measured in welding shops. THE FORMATION of toxic gases in welding shop air has been reported by severaI authors (FERRY and GINTHER, 1952). Argon arc welding has been regarded asa particularly dangerous method in this respect. Thus BENOIST and FRANT 0957) have measured the formation of ozone and nitrogen dioxide under different conditions and they have also paid some attention t the formation of phosgene in air contaminated with trichloroethylene. It is, however, difficult to generalize from the results of such investigations, although their value as examples of what may happen cannot b