RHS 260×140×6.3 vs RHS 250×150×6.3
RHS 260×140×6.3 is an RHS Hot-finished section from the UK Blue Book (SCI P363); RHS 250×150×6.3 is the closest equivalent in the European (Continental) range. RHS 260×140×6.3 carries more bending: 411 cm³ of plastic modulus against 402 cm³, 2.2% more. They weigh essentially the same, 38 kg/m and 38 kg/m. RHS 260×140×6.3 is deeper, 260 mm against 250 mm, which matters where the floor zone is tight.
| Property | RHS 260×140×6.3 RHS Hot-finished | RHS 250×150×6.3 RHS | Difference |
|---|---|---|---|
| Mass | 38 kg/m | 38 kg/m | same |
| Depth | 260 mm | 250 mm | +4.0% |
| Width | 140 mm | 150 mm | -6.7% |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 48.4 cm² | 48.4 cm² | same |
| Second moment, major (Iy) | 4,360 cm⁴ | 4,143 cm⁴ | +5.2% |
| Plastic modulus, major (Wpl,y) | 411 cm³ | 402 cm³ | +2.2% |
| Elastic modulus, major (Wel,y) | 335 cm³ | 331 cm³ | +1.2% |
| Second moment, minor (Iz) | 1,660 cm⁴ | 1,874 cm⁴ | -11.4% |
| Plastic modulus, minor (Wpl,z) | 267 cm³ | 283 cm³ | -5.7% |
| Radius of gyration, minor (iz) | 5.86 cm | 6.22 cm | -5.8% |
| Torsion constant (It) | 3,800 cm⁴ | 4,054 cm⁴ | -6.3% |
RHS 260×140×6.3 to BS EN 10210-2:2006; RHS 250×150×6.3 to EN 10219 · Continental Steel. Difference is expressed relative to RHS 250×150×6.3.
How to choose between them
On stiffness, RHS 260×140×6.3 has the larger second moment of area: 4,360 cm⁴ against 4,143 cm⁴, a difference of 5.2%. 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, RHS 260×140×6.3 is the more efficient section: 10.8 against 10.6 cm³ per kg/m, 2.2% 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. RHS Hot-finished sections are specified to BS EN 10210-2:2006 and RHS to EN 10219 · 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, RHS 260×140×6.3 is the stronger section and RHS 250×150×6.3 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.