To understand how this type of beam works, a person can picture a single sheet of steel lying flat on the ground. This sheet represents the bottom flange of the beam. A second sheet of steel with the same dimensions as the first can be placed in the center of this sheet, positioned at a 90-degree angle, then welded or forged in placed to form the web. A third sheet is then placed parallel to the first to form the second flange. In a standard I-beam, the flanges are generally narrower than the height of the web, while in a wide flange beam, they are often just as long as the web is tall.
Throughout the world, beam sizes are standardized, making it easier for engineers, architects, and builders to coordinate during construction. In the US, sizes are based on standards developed by American Society for Testing and Materials (ASTM) International or the American National Standards Institute (ANSI). Other countries may also use these standards, though some rely on their own set of beam sizing requirements.
The size of a wide flange beam in the US is always preceded by a "W." The numbers following this letter provide the depth of the web and the weight of the beam. For example, a beam marked W10x22 will have a 10 inch (25 cm) web depth and a weight of 22 pounds per foot (33 kg per m).