UB 838×292×226 vs H-900x300x15x23-213
UB 838×292×226 is an UB section from the UK Blue Book (SCI P363); H-900x300x15x23-213 is the closest equivalent in the European (Continental) range. UB 838×292×226 carries more bending: 9160 cm³ of plastic modulus against 8913 cm³, 2.8% more. H-900x300x15x23-213 is the lighter of the two at 213 kg/m against 226.5 kg/m, a saving of 6.3% on steel weight. H-900x300x15x23-213 is deeper, 890 mm against 850.9 mm, which matters where the floor zone is tight.
| Property | UB 838×292×226 UB | H-900x300x15x23-213 MB & MC | Difference |
|---|---|---|---|
| Mass | 226.5 kg/m | 213 kg/m | +6.3% |
| Depth | 850.9 mm | 890 mm | -4.4% |
| Width | 293.8 mm | 299 mm | -1.7% |
| Web thickness | 16.1 mm | 15 mm | +7.3% |
| Flange thickness | 26.8 mm | 23 mm | +16.5% |
| Area | 289 cm² | 271 cm² | +6.6% |
| Second moment, major (Iy) | 340,000 cm⁴ | 345,300 cm⁴ | -1.5% |
| Plastic modulus, major (Wpl,y) | 9,160 cm³ | 8,913 cm³ | +2.8% |
| Elastic modulus, major (Wel,y) | 7,980 cm³ | 7,760 cm³ | +2.8% |
| Second moment, minor (Iz) | 11,400 cm⁴ | 10,290 cm⁴ | +10.8% |
| Plastic modulus, minor (Wpl,z) | 1,210 cm³ | 1,085 cm³ | +11.5% |
| Radius of gyration, minor (iz) | 6.27 cm | 6.16 cm | +1.8% |
| Torsion constant (It) | 514 cm⁴ | 403 cm⁴ | +27.5% |
UB 838×292×226 to BS EN 10365:2017; H-900x300x15x23-213 to Continental Steel. Difference is expressed relative to H-900x300x15x23-213.
How to choose between them
On stiffness, H-900x300x15x23-213 has the larger second moment of area: 345,300 cm⁴ against 340,000 cm⁴, a difference of 1.5%. 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, H-900x300x15x23-213 is the more efficient section: 41.8 against 40.4 cm³ per kg/m, 3.4% 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: UB 838×292×226 has 1210 cm³ of minor-axis plastic modulus against 1085 cm³, 11.5% 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.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. UB sections are specified to BS EN 10365:2017 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 6.3% weight.
In short, UB 838×292×226 is the stronger section and H-900x300x15x23-213 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.