Read weight charts for structural steel by finding the correct nominal size and wall thickness for your steel stock, and then finding the corresponding weight measurement. Most structural steel weight charts list stock weight in units of weight per unit length of stock. In the United States, weights are usually given in pounds per foot of stock, while kilograms per meter is more common in countries that use the metric system.
Get the correct weight measurement for your structural steel by first collecting the necessary measurements. Nominal size is the distance between one inside wall of the stock and the other. Round structural steel only uses one nominal size measurement, because the distance between the inner walls is the same at all points. Rectangular and square structural steel use two nominal size measurements to specify the length between the top and bottom, and right and left walls. For instance, a piece of rectangular structural steel with 2 inches between the top and bottom walls and 1 inch between the left and right has a nominal size of 2 x 1 inches.
Wall thickness is the measurement between the inner and outer walls of the structural steel tubing. Outer diameter is the distance from one outer wall to the opposite outer wall. Because outer diameter is just the steel's outer diameter added to its nominal size, many weight charts exclude this measurement.