UB 457×191×106 vs H-450x200x14x19
UB 457×191×106 is an UB section from the UK Blue Book (SCI P363); H-450x200x14x19 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 2390 cm³ against 2399 cm³ of plastic modulus, a difference of 0.4%. UB 457×191×106 is the lighter of the two at 105.8 kg/m against 110 kg/m, a saving of 3.8% on steel weight. Both are about 465 mm deep, so either fits the same construction zone.
| Property | UB 457×191×106 UB | H-450x200x14x19 MB & MC | Difference |
|---|---|---|---|
| Mass | 105.8 kg/m | 110 kg/m | -3.8% |
| Depth | 469.2 mm | 460 mm | +2.0% |
| Width | 194 mm | 205 mm | -5.4% |
| Web thickness | 12.6 mm | 14 mm | -10.0% |
| Flange thickness | 20.6 mm | 19 mm | +8.4% |
| Area | 135 cm² | 140 cm² | -3.6% |
| Second moment, major (Iy) | 48,900 cm⁴ | 47,860 cm⁴ | +2.2% |
| Plastic modulus, major (Wpl,y) | 2,390 cm³ | 2,399 cm³ | -0.4% |
| Elastic modulus, major (Wel,y) | 2,080 cm³ | 2,081 cm³ | same |
| Second moment, minor (Iz) | 2,510 cm⁴ | 2,742 cm⁴ | -8.5% |
| Plastic modulus, minor (Wpl,z) | 405 cm³ | 423 cm³ | -4.3% |
| Radius of gyration, minor (iz) | 4.32 cm | 4.43 cm | -2.5% |
| Torsion constant (It) | 146 cm⁴ | 152 cm⁴ | -3.9% |
UB 457×191×106 to BS EN 10365:2017; H-450x200x14x19 to Continental Steel. Difference is expressed relative to H-450x200x14x19.
How to choose between them
On stiffness, UB 457×191×106 has the larger second moment of area: 48,900 cm⁴ against 47,860 cm⁴, a difference of 2.2%. 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, UB 457×191×106 is the more efficient section: 22.6 against 21.8 cm³ per kg/m, 3.6% 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. 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 3.8% weight.
In short, H-450x200x14x19 is the stronger section and UB 457×191×106 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.