Structural steel comes in standard rolled shapes, each identified by a letter and a size designation. This chart summarizes the common shapes and how they are named.
| Shape | Example | Description | Common use |
|---|---|---|---|
| Wide flange (W) | W12x26 | I-shape, wide parallel flanges | Beams and columns |
| Standard beam (S) | S12x31.8 | I-shape, sloped inner flanges | Beams, rails |
| Channel (C) | C9x15 | C-shape with sloped flanges | Frames, purlins, supports |
| Angle (L) | L4x4x1/4 | L-shape, equal or unequal legs | Bracing, frames, lintels |
| Structural tee (WT) | WT6x20 | T-shape cut from a W beam | Truss chords, bracing |
| Hollow section (HSS) | HSS4x4x1/4 | Square, rectangular, or round tube | Columns, frames, railings |
| Pipe | Pipe 4 STD | Round hollow section | Columns, posts, handrails |
| Flat bar | FB 1/2 x 3 | Solid rectangular bar | Plates, ties, miscellaneous |
Reading a designation
A designation like W12x26 means a wide-flange shape about 12 inches deep that weighs 26 pounds per foot. The first number is the nominal depth and the second is the weight per foot, the two figures engineers use most when sizing members.
Depth then weight. In W12x26, the 12 is the nominal depth in inches and the 26 is the weight in pounds per foot. The same pattern applies to S, C, and WT shapes.
See the Steel Beam Properties Chart and the Beam Span Chart.
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