Steel standard weights are specifications that detail and ensure consistency of steel products used in construction. These standards are normally listed in books or charts that list the piece, available sizes, weight per foot and its dimensions.
For example, the standards for rebar specify the available bar size designations, the diameter of each bar size, the weight per foot for each bar size, the weight per 20 foot bar, the diameter of each bar size cross section and the perimeter of each bar size. Engineers rely on this information to calculate the amount of materials needed to support various loads and design buildings. Contractors use this information to decide how much material to purchase. Other specifications or standards apply to I-bars and beams and other steel products. Some companies may express standard steel weight by a formula, such as standard weight equaling diameter squared divided by 162.