In the United States, steel I-beams are commonly specified using the depth and weight of the beam. For example, a "W10x22" beam is approximately 10 in (25 cm) in depth (nominal height of the I-beam from the outer face of one flange to the outer face of the other flange) and weighs 22 lb/ft (33 kg/m).
How do you read a beam size?
In Canada and the United States, steel I-beams are commonly specified using the depth (in inches) and weight of the beam (in pounds per foot). For example, a “4 x 13” I-beam is approximately 4 inches in depth (the measurement taken from the outer face of the first flange, to the outer face of the opposite flange).2015-02-21