UB 457×152×74 vs H-450x200x9x14-74.9
UB 457×152×74 is an UB section from the UK Blue Book (SCI P363); H-450x200x9x14-74.9 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 1630 cm³ against 1652 cm³ of plastic modulus, a difference of 1.3%. They weigh essentially the same, 74.2 kg/m and 74.9 kg/m. UB 457×152×74 is deeper, 462 mm against 450 mm, which matters where the floor zone is tight.
| Property | UB 457×152×74 UB | H-450x200x9x14-74.9 MB & MC | Difference |
|---|---|---|---|
| Mass | 74.2 kg/m | 74.9 kg/m | -0.9% |
| Depth | 462 mm | 450 mm | +2.7% |
| Width | 154.4 mm | 200 mm | -22.8% |
| Web thickness | 9.6 mm | 9 mm | +6.7% |
| Flange thickness | 17 mm | 14 mm | +21.4% |
| Area | 94.5 cm² | 95.4 cm² | -0.9% |
| Second moment, major (Iy) | 32,700 cm⁴ | 32,890 cm⁴ | -0.6% |
| Plastic modulus, major (Wpl,y) | 1,630 cm³ | 1,652 cm³ | -1.3% |
| Elastic modulus, major (Wel,y) | 1,410 cm³ | 1,462 cm³ | -3.6% |
| Second moment, minor (Iz) | 1,050 cm⁴ | 1,870 cm⁴ | -43.9% |
| Plastic modulus, minor (Wpl,z) | 213 cm³ | 290 cm³ | -26.6% |
| Radius of gyration, minor (iz) | 3.33 cm | 4.43 cm | -24.8% |
| Torsion constant (It) | 65.9 cm⁴ | 51.6 cm⁴ | +27.7% |
UB 457×152×74 to BS EN 10365:2017; H-450x200x9x14-74.9 to Continental Steel. Difference is expressed relative to H-450x200x9x14-74.9.
How to choose between them
On stiffness, H-450x200x9x14-74.9 has the larger second moment of area: 32,890 cm⁴ against 32,700 cm⁴, a difference of 0.6%. 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 (22.0 against 22.1 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.
The two diverge much more about the minor axis: H-450x200x9x14-74.9 has 290 cm³ of minor-axis plastic modulus against 213 cm³, 26.6% 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 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.