SHS 250×250×7.1 vs SHS 260×260×6.3
SHS 250×250×7.1 is an SHS Hot-finished section from the UK Blue Book (SCI P363); SHS 260×260×6.3 is the closest equivalent in the European (Continental) range. SHS 250×250×7.1 carries more bending: 622 cm³ of plastic modulus against 603 cm³, 3.2% more. SHS 260×260×6.3 is the lighter of the two at 49.9 kg/m against 53.7 kg/m, a saving of 7.6% on steel weight. SHS 260×260×6.3 is deeper, 260 mm against 250 mm, which matters where the floor zone is tight.
| Property | SHS 250×250×7.1 SHS Hot-finished | SHS 260×260×6.3 SHS | Difference |
|---|---|---|---|
| Mass | 53.7 kg/m | 49.9 kg/m | +7.6% |
| Depth | 250 mm | 260 mm | -3.8% |
| Width | 250 mm | 260 mm | -3.8% |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 68.4 cm² | 63.5 cm² | +7.7% |
| Second moment, major (Iy) | 6,700 cm⁴ | 6,788 cm⁴ | -1.3% |
| Plastic modulus, major (Wpl,y) | 622 cm³ | 603 cm³ | +3.2% |
| Elastic modulus, major (Wel,y) | 536 cm³ | 522 cm³ | +2.7% |
| Second moment, minor (Iz) | 6,700 cm⁴ | 6,788 cm⁴ | -1.3% |
| Plastic modulus, minor (Wpl,z) | 622 cm³ | 603 cm³ | +3.2% |
| Radius of gyration, minor (iz) | 9.9 cm | 10.3 cm | -3.9% |
| Torsion constant (It) | 10,300 cm⁴ | 10,420 cm⁴ | -1.2% |
SHS 250×250×7.1 to BS EN 10210-2:2006; SHS 260×260×6.3 to EN 10219 · Continental Steel. Difference is expressed relative to SHS 260×260×6.3.
How to choose between them
On stiffness, SHS 260×260×6.3 has the larger second moment of area: 6,788 cm⁴ against 6,700 cm⁴, a difference of 1.3%. 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, SHS 260×260×6.3 is the more efficient section: 12.1 against 11.6 cm³ per kg/m, 4.1% 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. SHS Hot-finished sections are specified to BS EN 10210-2:2006 and SHS 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 7.6% weight.
In short, SHS 250×250×7.1 is the stronger section and SHS 260×260×6.3 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.