Hot work can throw sparks and molten material more than 35 feet during welding, cutting, and grinding. These sparks and hot slag are typically burning above 1,000°F—more than enough to easily ignite paper, wood, flammable liquids, vapors, and any other combustibles in the area.

Fire watches are required during any hot work activity and for at least 30 minutes after the work is completed in order to reduce the potential for ignitions and large fire losses.