W 21X132 vs HE 550 B
W 21X132 is an W section from the American AISC Shapes Database; HE 550 B is the closest equivalent in the European (Continental) range. HE 550 B carries more bending: 5590 cm³ of plastic modulus against 5456.9 cm³, 2.4% more. They weigh essentially the same, 196.4 kg/m and 199 kg/m. Both are about 552 mm deep, so either fits the same construction zone.
| Property | W 21X132 W | HE 550 B HE | Difference |
|---|---|---|---|
| Mass | 196.4 kg/m | 199 kg/m | -1.3% |
| Depth | 553.7 mm | 550 mm | +0.7% |
| Width | 315 mm | 300 mm | +5.0% |
| Web thickness | 16.5 mm | 15 mm | +10.0% |
| Flange thickness | 26.4 mm | 29 mm | -9.0% |
| Area | 250.3 cm² | 254 cm² | -1.5% |
| Second moment, major (Iy) | 134,027 cm⁴ | 137,000 cm⁴ | -2.2% |
| Plastic modulus, major (Wpl,y) | 5,456.9 cm³ | 5,590 cm³ | -2.4% |
| Elastic modulus, major (Wel,y) | 4,834.2 cm³ | 4,970 cm³ | -2.7% |
| Second moment, minor (Iz) | 13,861 cm⁴ | 13,100 cm⁴ | +5.8% |
| Plastic modulus, minor (Wpl,z) | 1,348.7 cm³ | 1,340 cm³ | +0.6% |
| Radius of gyration, minor (iz) | 7.44 cm | 7.17 cm | +3.8% |
| Torsion constant (It) | 470.3 cm⁴ | 610 cm⁴ | -22.9% |
W 21X132 to AISC Shapes Database v16.0; HE 550 B to EN 10365 · Continental Steel. Difference is expressed relative to HE 550 B.
How to choose between them
On stiffness, HE 550 B has the larger second moment of area: 137,000 cm⁴ against 134,027 cm⁴, a difference of 2.2%. This matters more often than the strength comparison, because on normal floor spans deflection rather than bending capacity sets the beam size - so if the two are close on modulus but apart on inertia, the stiffer one is usually the better answer even when it is not the stronger one.
Measured as bending capacity per kilogram, the two are equally efficient (27.8 against 28.1 cm³ per kg/m), so on a pure steel-tonnage basis there is nothing to choose between them. The decision comes down to availability, connection detailing and what the rest of the frame uses.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. W sections are specified to AISC Shapes Database v16.0 and HE to EN 10365 · Continental Steel; the steel grades, tolerances and available lengths differ, connection details and bolt gauges are set out differently, and the two are rarely both stocked in the same market. Check availability before changing a section on a drawing to save a marginal amount of weight.
In short, HE 550 B is the stronger section and W 21X132 is the lighter one; where those are the same section, it is the clear choice, and where they are not, decide on whether your design is governed by capacity or by tonnage.