When welding in confined space or on contaminated metals mechanical ventilation should be at what?

Answer 1

When welding in confined spaces or on contaminated metals, mechanical ventilation should be maintained at a rate sufficient to ensure that the concentration of harmful fumes and gases is kept below permissible exposure limits. Typically, this involves providing a minimum of 4 to 10 air changes per hour, depending on the specific environment and contaminants present. It is essential to assess the area to determine the appropriate ventilation needs while also considering the type of welding process being used. Always consult safety guidelines and standards relevant to the specific situation.

Answer 2

When welding in confined spaces or on contaminated metals, mechanical ventilation should be set to maintain a minimum airflow rate of at least 200 cubic feet per minute (CFM) to ensure adequate dilution and removal of harmful fumes and gases. It's essential to monitor the oxygen levels and ensure they remain above 19.5% to prevent asphyxiation. Additionally, local exhaust ventilation may be necessary to capture fumes at the source. Always follow relevant safety regulations and guidelines for specific situations.