UC 356×368×153 vs H-350x350x14x22
UC 356×368×153 is an UC section from the UK Blue Book (SCI P363); H-350x350x14x22 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 2960 cm³ against 2979 cm³ of plastic modulus, a difference of 0.6%. UC 356×368×153 is the lighter of the two at 152.9 kg/m against 159 kg/m, a saving of 3.8% on steel weight. Both are about 359 mm deep, so either fits the same construction zone.
| Property | UC 356×368×153 UC | H-350x350x14x22 MB & MC | Difference |
|---|---|---|---|
| Mass | 152.9 kg/m | 159 kg/m | -3.8% |
| Depth | 362 mm | 356 mm | +1.7% |
| Width | 370.5 mm | 352 mm | +5.3% |
| Web thickness | 12.3 mm | 14 mm | -12.1% |
| Flange thickness | 20.7 mm | 22 mm | -5.9% |
| Area | 195 cm² | 202 cm² | -3.5% |
| Second moment, major (Iy) | 48,600 cm⁴ | 47,590 cm⁴ | +2.1% |
| Plastic modulus, major (Wpl,y) | 2,960 cm³ | 2,979 cm³ | -0.6% |
| Elastic modulus, major (Wel,y) | 2,680 cm³ | 2,674 cm³ | +0.2% |
| Second moment, minor (Iz) | 17,600 cm⁴ | 16,000 cm⁴ | +10.0% |
| Plastic modulus, minor (Wpl,z) | 1,430 cm³ | 1,382 cm³ | +3.5% |
| Radius of gyration, minor (iz) | 9.49 cm | 8.9 cm | +6.6% |
| Torsion constant (It) | 251 cm⁴ | 305 cm⁴ | -17.7% |
UC 356×368×153 to BS EN 10365:2017; H-350x350x14x22 to Continental Steel. Difference is expressed relative to H-350x350x14x22.
How to choose between them
On stiffness, UC 356×368×153 has the larger second moment of area: 48,600 cm⁴ against 47,590 cm⁴, a difference of 2.1%. 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, UC 356×368×153 is the more efficient section: 19.4 against 18.7 cm³ per kg/m, 3.3% 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. UC 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-350x350x14x22 is the stronger section and UC 356×368×153 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.