W 14X120 vs H-350x350x16x25
W 14X120 is an W section from the American AISC Shapes Database; H-350x350x16x25 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 3474.1 cm³ against 3424 cm³ of plastic modulus, a difference of 1.5%. They weigh essentially the same, 178.6 kg/m and 181 kg/m. Both are about 365 mm deep, so either fits the same construction zone.
| Property | W 14X120 W | H-350x350x16x25 MB & MC | Difference |
|---|---|---|---|
| Mass | 178.6 kg/m | 181 kg/m | -1.3% |
| Depth | 368.3 mm | 362 mm | +1.7% |
| Width | 373.4 mm | 354 mm | +5.5% |
| Web thickness | 15 mm | 16 mm | -6.3% |
| Flange thickness | 23.9 mm | 25 mm | -4.4% |
| Area | 227.7 cm² | 230 cm² | -1.0% |
| Second moment, major (Iy) | 57,440 cm⁴ | 55,190 cm⁴ | +4.1% |
| Plastic modulus, major (Wpl,y) | 3,474.1 cm³ | 3,424 cm³ | +1.5% |
| Elastic modulus, major (Wel,y) | 3,113.5 cm³ | 3,049 cm³ | +2.1% |
| Second moment, minor (Iz) | 20,603 cm⁴ | 18,500 cm⁴ | +11.4% |
| Plastic modulus, minor (Wpl,z) | 1,671.5 cm³ | 1,591 cm³ | +5.1% |
| Radius of gyration, minor (iz) | 9.5 cm | 8.96 cm | +6.0% |
| Torsion constant (It) | 390 cm⁴ | 445 cm⁴ | -12.4% |
W 14X120 to AISC Shapes Database v16.0; H-350x350x16x25 to Continental Steel. Difference is expressed relative to H-350x350x16x25.
How to choose between them
On stiffness, W 14X120 has the larger second moment of area: 57,440 cm⁴ against 55,190 cm⁴, a difference of 4.1%. 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 of steel, W 14X120 is the more efficient section: 19.5 against 18.9 cm³ per kg/m, 2.8% better. Over a floor of repeated beams that difference is real tonnage, though it is often outweighed by whichever section the fabricator can actually source.
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 MB & MC to 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, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.