| (1) OZONE (O3) : Due to ionization of oxygen (O2) by the ultraviolet light (UV) from arc welding. UV + O2 = O3 Ozone is classified as a pulmonary irritation & can cause pulmonary edema. (2) CARBON MONOXIDE (CO) : From the ultraviolet effects on carbon dioxide (CO2) in the shielding gas. UV + CO2 = CO Carbon monoxide is classified as a chemical asphyxiant resulting in anemic hypoxia. Hemoglobin has a 220 times greater affinity for carbon monoxide, compared with oxygen, with the resultant carboxy hemoglobin complex formation in the blood. Carbon monoxide is an odourless and colourless gas. Acute symptoms include dizziness, headache & mental confusion. The airborne concentration of carbon monoxide generated from the welding process was determined to be < 5 ppm (measured at source). Note: A poorly adjusted flame will result in higher amounts of carbon monoxide. (3) CARBON DIOXIDE : From the decomposition of fluxes Carbon dioxide is classified as a simple asphyxiant. It displaces oxygen, reducing the amount of oxygen available in the air. Oxygen depletion may cause dizziness, disorientation, inattention, unconsciousness or even death if the level of oxygen drops too low. The minimum acceptable oxygen content in the air is 19.5%. (4) NITROGEN OXIDES are formed from the heating of atmospheric oxygen & nitrogen (in the presence of ultraviolet light). The oxide usually consists of nitrogen dioxide (NO2) and nitric oxide (NO). NO2 is the predominant oxide present in the fume. NO2 is irritating to the eyes, nose & throat at low concentrations (10-20 ppm) and at higher concentrations results in pulmonary edema. (5) HYDROGEN CHLORIDE & PHOSGENE : These are produced by the reaction between ultraviolet light and vapours from chlorinated hydrocarbon de-greasing solvents. Both of these gases irritate and can damage the respiratory system. Also, LUNG IRRITATION/INJURY/CANCER: • Lung, nose & throat irritation, bronchitis, emphysema & asthma • Welders suffer a greater incidence of bronchitis, compared with the general population • 40% increase of lung cancer reported among welders, compared with the general population. You can also refer AWS hand book on Fumes and gases for more info, which I do not have handy now. ವಂದನೆಗಳೊಂದಿಗೆ / Best regards, Nandesh Kumar A Abu Dhabi, UAE P.S. : Please don't print this e-mail unless you really need to. --- On Sun, 18/11/12, welding <samirmehta.jnd@gmail.com> wrote:
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