Trades in this sector involve making and repairing metal parts used in the construction of buildings, bridges, tanks, towers, boilers, pressure-vessels and other structures and products. Workers lay out, cut and fabricate structural steel, plate and miscellaneous ferrous and non-ferrous metals for use in a wide variety of manufacturing and construction industries. They also assemble and fit metal sections and plates together to form complete units or sub-units such as frames, plates, girders and chutes that are used later in the assembly process. Some of these workers are employed in structural steel, boiler and plate-work fabrication plants. Others are employed by heavy machinery manufacturing companies and enterprises that build and repair ships.