Applies to iron or steel work not otherwise classified. Confined principally to groundwork where no structural operations are involved. Includes setting up iron or steel tanks that rest on the ground. Also includes the erection of cylindrical tanks not resting on steel framework. Contemplates iron or steel work in connection with the installation of lock gates, blast furnaces, windmills, outside railings, coal chutes and the placement of iron or steel fronts as alterations to existing buildings. Welding operations are considered incidental to the main operations. Includes iron or steel work in connection with building raising or moving operations. Also applies to the set up of iron or steel components in connection with oil rigs or derricks at their customers' drilling sites, and the installation or construction of fire or burglar proof vaults. Also applies to the wrecking of iron or steel structures. Refer to code 6400 for metal fence erection, code 5069 for iron or steel erection construction of dwellings and frame structures not over two stories in height, code 5404 for iron or steel erection of frame structures, code 5535 for sheet metal work and installation.