W 10X39 vs HP 10X42
W 10X39 is an W section from the American AISC Shapes Database; HP 10X42 is the closest equivalent in the American AISC Shapes Database. HP 10X42 carries more bending: 791.5 cm³ of plastic modulus against 766.91 cm³, 3.1% more. W 10X39 is the lighter of the two at 58 kg/m against 62.5 kg/m, a saving of 7.2% on steel weight. W 10X39 is deeper, 252 mm against 246.4 mm, which matters where the floor zone is tight.
| Property | W 10X39 W | HP 10X42 HP | Difference |
|---|---|---|---|
| Mass | 58 kg/m | 62.5 kg/m | -7.2% |
| Depth | 252 mm | 246.4 mm | +2.3% |
| Width | 202.9 mm | 256.5 mm | -20.9% |
| Web thickness | 8 mm | 10.5 mm | -23.8% |
| Flange thickness | 13.5 mm | 10.7 mm | +26.2% |
| Area | 74.2 cm² | 80 cm² | -7.2% |
| Second moment, major (Iy) | 8,699 cm⁴ | 8,741 cm⁴ | -0.5% |
| Plastic modulus, major (Wpl,y) | 766.91 cm³ | 791.5 cm³ | -3.1% |
| Elastic modulus, major (Wel,y) | 689.9 cm³ | 711.2 cm³ | -3.0% |
| Second moment, minor (Iz) | 1,873 cm⁴ | 2,984 cm⁴ | -37.2% |
| Plastic modulus, minor (Wpl,z) | 281.86 cm³ | 357.24 cm³ | -21.1% |
| Radius of gyration, minor (iz) | 5.03 cm | 6.12 cm | -17.8% |
| Torsion constant (It) | 40.62 cm⁴ | 33.84 cm⁴ | +20.0% |
W 10X39 to AISC Shapes Database v16.0; HP 10X42 to AISC Shapes Database v16.0. Difference is expressed relative to HP 10X42.
How to choose between them
On stiffness, HP 10X42 has the larger second moment of area: 8,741 cm⁴ against 8,699 cm⁴, a difference of 0.5%. 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 10X39 is the more efficient section: 13.2 against 12.7 cm³ per kg/m, 4.4% 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.
The two diverge much more about the minor axis: HP 10X42 has 357.24 cm³ of minor-axis plastic modulus against 281.86 cm³, 21.1% more. If the member sees any minor-axis bending, or if it is unrestrained over a long length and lateral-torsional buckling governs, that gap decides the comparison even though the major-axis numbers looked equivalent.
In short, HP 10X42 is the stronger section and W 10X39 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.