Boiler accessories, Heating, ventilation, air conditioning (HVAC) and refrigeration equipment, Construction, Bottoms and shells for boilers and water heaters, Tanks and vats, metal, Metal pipework, valves and containers, Cylinders, bottles and cartridges, metal, for gases, Floating roofs, metal, internal, for storage tanks, Bottoms and ends, metal, for tanks containing liquids, Closure units for pressure vessels