UB 457×191×67 vs H-450x200x8x12-66.2
UB 457×191×67 is an UB section from the UK Blue Book (SCI P363); H-450x200x8x12-66.2 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 1470 cm³ against 1450 cm³ of plastic modulus, a difference of 1.4%. They weigh essentially the same, 67.1 kg/m and 66.2 kg/m. Both are about 450 mm deep, so either fits the same construction zone.
| Property | UB 457×191×67 UB | H-450x200x8x12-66.2 MB & MC | Difference |
|---|---|---|---|
| Mass | 67.1 kg/m | 66.2 kg/m | +1.4% |
| Depth | 453.4 mm | 446 mm | +1.7% |
| Width | 189.9 mm | 199 mm | -4.6% |
| Web thickness | 8.5 mm | 8 mm | +6.3% |
| Flange thickness | 12.7 mm | 12 mm | +5.8% |
| Area | 85.5 cm² | 84.3 cm² | +1.4% |
| Second moment, major (Iy) | 29,400 cm⁴ | 28,700 cm⁴ | +2.4% |
| Plastic modulus, major (Wpl,y) | 1,470 cm³ | 1,450 cm³ | +1.4% |
| Elastic modulus, major (Wel,y) | 1,300 cm³ | 1,287 cm³ | +1.0% |
| Second moment, minor (Iz) | 1,450 cm⁴ | 1,581 cm⁴ | -8.3% |
| Plastic modulus, minor (Wpl,z) | 237 cm³ | 247 cm³ | -4.0% |
| Radius of gyration, minor (iz) | 4.12 cm | 4.33 cm | -4.8% |
| Torsion constant (It) | 37.1 cm⁴ | 38.3 cm⁴ | -3.1% |
UB 457×191×67 to BS EN 10365:2017; H-450x200x8x12-66.2 to Continental Steel. Difference is expressed relative to H-450x200x8x12-66.2.
How to choose between them
On stiffness, UB 457×191×67 has the larger second moment of area: 29,400 cm⁴ against 28,700 cm⁴, a difference of 2.4%. 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 (21.9 against 21.9 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. 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.