UB 533×165×85 vs H-500x200x10x16-88.2
UB 533×165×85 is an UB section from the UK Blue Book (SCI P363); H-500x200x10x16-88.2 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 2100 cm³ against 2130 cm³ of plastic modulus, a difference of 1.4%. UB 533×165×85 is the lighter of the two at 84.8 kg/m against 88.2 kg/m, a saving of 3.9% on steel weight. UB 533×165×85 is deeper, 534.9 mm against 500 mm, which matters where the floor zone is tight.
| Property | UB 533×165×85 UB | H-500x200x10x16-88.2 MB & MC | Difference |
|---|---|---|---|
| Mass | 84.8 kg/m | 88.2 kg/m | -3.9% |
| Depth | 534.9 mm | 500 mm | +7.0% |
| Width | 166.5 mm | 200 mm | -16.8% |
| Web thickness | 10.3 mm | 10 mm | +3.0% |
| Flange thickness | 16.5 mm | 16 mm | +3.1% |
| Area | 108 cm² | 112 cm² | -3.6% |
| Second moment, major (Iy) | 48,500 cm⁴ | 46,810 cm⁴ | +3.6% |
| Plastic modulus, major (Wpl,y) | 2,100 cm³ | 2,130 cm³ | -1.4% |
| Elastic modulus, major (Wel,y) | 1,820 cm³ | 1,872 cm³ | -2.8% |
| Second moment, minor (Iz) | 1,270 cm⁴ | 2,138 cm⁴ | -40.6% |
| Plastic modulus, minor (Wpl,z) | 243 cm³ | 333 cm³ | -27.0% |
| Radius of gyration, minor (iz) | 3.44 cm | 4.36 cm | -21.1% |
| Torsion constant (It) | 73.8 cm⁴ | 75.9 cm⁴ | -2.8% |
UB 533×165×85 to BS EN 10365:2017; H-500x200x10x16-88.2 to Continental Steel. Difference is expressed relative to H-500x200x10x16-88.2.
How to choose between them
On stiffness, UB 533×165×85 has the larger second moment of area: 48,500 cm⁴ against 46,810 cm⁴, a difference of 3.6%. 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 of steel, UB 533×165×85 is the more efficient section: 24.8 against 24.1 cm³ per kg/m, 2.5% 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: H-500x200x10x16-88.2 has 333 cm³ of minor-axis plastic modulus against 243 cm³, 27.0% 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 3.9% weight.
In short, H-500x200x10x16-88.2 is the stronger section and UB 533×165×85 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.