Orbital Welding and Toxic Gases

Orbital welding is an automated, gas tungsten arc welding (GTAW) procedure, typically used to weld steel pipe or tubing. Orbital welding allows high-quality welds to be produced quickly and easily, but the process also uses or generates various gases that can be harmful to human health.

Manganese

The gray/white metal, manganese, is added to steel to improve its hardness, stiffness and strength. However, prolonged exposure to manganese fumes can produce symptoms akin to Parkinson's disease; tremors, stiffness of the muscles and balance problems are all symptomatic of manganese poisoning.

Carbon Dioxide

Carbon dioxide, in conjunction with the inert gas argon, may be used as a shielding gas in the orbital welding process. Exposure to carbon dioxide should be limited to 5,000 parts per million (ppm) for an eight-hour period, or 15,000 ppm for a 15-minute period.

Ozone

Ozone, a form of oxygen, can be generated when ultraviolet (UV) light from the welding arc passes through air. Minor exposure to ozone can produce irritation of the respiratory system, but major, long-term exposure can result in severe lung damage.

References

• "Welding Essentials: Questions & Answers"; William L. Galvery, Frank M. Marlow; 2001
• TWI: What are the hazards from gases during welding and cutting?