UB 610×229×140 vs HE 650 AA
UB 610×229×140 is an UB section from the UK Blue Book (SCI P363); HE 650 AA is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 4140 cm³ against 4160 cm³ of plastic modulus, a difference of 0.5%. They weigh essentially the same, 139.9 kg/m and 138 kg/m. Both are about 619 mm deep, so either fits the same construction zone.
| Property | UB 610×229×140 UB | HE 650 AA HE | Difference |
|---|---|---|---|
| Mass | 139.9 kg/m | 138 kg/m | +1.4% |
| Depth | 617.2 mm | 620 mm | -0.5% |
| Width | 230.2 mm | 300 mm | -23.3% |
| Web thickness | 13.1 mm | 12.5 mm | +4.8% |
| Flange thickness | 22.1 mm | 16 mm | +38.1% |
| Area | 178 cm² | 176 cm² | +1.1% |
| Second moment, major (Iy) | 112,000 cm⁴ | 114,000 cm⁴ | -1.8% |
| Plastic modulus, major (Wpl,y) | 4,140 cm³ | 4,160 cm³ | -0.5% |
| Elastic modulus, major (Wel,y) | 3,620 cm³ | 3,680 cm³ | -1.6% |
| Second moment, minor (Iz) | 4,510 cm⁴ | 7,220 cm⁴ | -37.5% |
| Plastic modulus, minor (Wpl,z) | 611 cm³ | 751 cm³ | -18.6% |
| Radius of gyration, minor (iz) | 5.03 cm | 6.41 cm | -21.5% |
| Torsion constant (It) | 216 cm⁴ | 158 cm⁴ | +36.7% |
UB 610×229×140 to BS EN 10365:2017; HE 650 AA to EN 10365 · Continental Steel. Difference is expressed relative to HE 650 AA.
How to choose between them
On stiffness, HE 650 AA has the larger second moment of area: 114,000 cm⁴ against 112,000 cm⁴, a difference of 1.8%. 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 (29.6 against 30.1 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.
The two diverge much more about the minor axis: HE 650 AA has 751 cm³ of minor-axis plastic modulus against 611 cm³, 18.6% 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 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 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.