UC 254×254×89 vs HE 260 B
UC 254×254×89 is an UC section from the UK Blue Book (SCI P363); HE 260 B is the closest equivalent in the European (Continental) range. HE 260 B carries more bending: 1280 cm³ of plastic modulus against 1220 cm³, 4.7% more. UC 254×254×89 is the lighter of the two at 88.9 kg/m against 93 kg/m, a saving of 4.4% on steel weight. Both are about 260 mm deep, so either fits the same construction zone.
| Property | UC 254×254×89 UC | HE 260 B HE | Difference |
|---|---|---|---|
| Mass | 88.9 kg/m | 93 kg/m | -4.4% |
| Depth | 260.3 mm | 260 mm | +0.1% |
| Width | 256.3 mm | 260 mm | -1.4% |
| Web thickness | 10.3 mm | 10 mm | +3.0% |
| Flange thickness | 17.3 mm | 17.5 mm | -1.1% |
| Area | 113 cm² | 118 cm² | -4.2% |
| Second moment, major (Iy) | 14,300 cm⁴ | 14,900 cm⁴ | -4.0% |
| Plastic modulus, major (Wpl,y) | 1,220 cm³ | 1,280 cm³ | -4.7% |
| Elastic modulus, major (Wel,y) | 1,100 cm³ | 1,150 cm³ | -4.3% |
| Second moment, minor (Iz) | 4,860 cm⁴ | 5,140 cm⁴ | -5.4% |
| Plastic modulus, minor (Wpl,z) | 575 cm³ | 602 cm³ | -4.5% |
| Radius of gyration, minor (iz) | 6.55 cm | 6.58 cm | -0.5% |
| Torsion constant (It) | 102 cm⁴ | 127 cm⁴ | -19.7% |
UC 254×254×89 to BS EN 10365:2017; HE 260 B to EN 10365 · Continental Steel. Difference is expressed relative to HE 260 B.
How to choose between them
On stiffness, HE 260 B has the larger second moment of area: 14,900 cm⁴ against 14,300 cm⁴, a difference of 4.0%. 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 (13.7 against 13.8 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. UC sections are specified to BS EN 10365:2017 and HE to EN 10365 · 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 4.4% weight.
In short, HE 260 B is the stronger section and UC 254×254×89 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.