Final answer:
C) 30 minutes. The fire watch at the end of a welding operation must last at least 30 minutes, as OSHA guidelines state. This period could extend depending on the specific situation, to prevent any delayed ignition of materials exposed to welding.
Step-by-step explanation:
The question deals with safety protocols that are vital during and after welding operations. Specifically, it asks about the duration of the fire watch that should be maintained after the completion of a welding process. According to widely accepted safety guidelines, including those outlined by organizations such as OSHA (Occupational Safety and Health Administration), the fire watch period should last at least 30 minutes after the welding operation. However, this time can be longer depending on the specific circumstances and the materials involved. It's crucial for the fire watch to stay alert for any signs of smoldering or fire, as the heat from welding can cause materials to ignite long after the actual welding has stopped. It is an essential practice in any fabrication, construction, or repair activity involving welding since it ensures that any potential fires are caught and dealt with promptly.