Direct Answer
Structural steel sections follow AISC naming conventions: W shapes are wide-flange beams (e.g., W12×53 means 12" nominal depth, 53 lb/ft weight). HSS sections use HSS depth×width×wall thickness. L shapes use L leg1×leg2×thickness. Pipe sections use Pipe 4 Std (4" nominal diameter, standard wall). These designations appear on piece mark drawings and BOM.
Full Explanation
Common section types in structural steel: W (wide flange, most common for columns and beams), S (American Standard I-beam, older designation), C (channel), MC (miscellaneous channel), L (angle — single or double), WT (structural tee, cut from W shape), HSS (hollow structural section — rectangular or square), Pipe (round HSS), PL (plate), and bars. Each has a specific ASTM grade: W shapes are typically A992, HSS is A500 Grade B or C, plates are A36 or A572.
What This Means for Your Shop
Section designation errors on purchase orders are costly. Always order from the BOM, not from design drawings. Verify that the section in hand matches the piece mark drawing before cutting.
Common Mistakes
Ordering W14×90 when the drawing calls for W14×99 — the depths are similar but the weight and capacity differ. Also: confusing HSS 8×8×1/4 (rectangular) with HSS 8×1/4 (pipe equivalent).
Recommended Process
Create a material check procedure: scan piece mark drawing, find section designation, compare to physical section using a steel scale and AISC section table. Record section lot numbers and certifications in your QC package.