SHS 250×250×12.5 vs SHS 254×254×12.7
SHS 250×250×12.5 is an SHS Hot-finished section from the UK Blue Book (SCI P363); SHS 254×254×12.7 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 1040 cm³ against 1023 cm³ of plastic modulus, a difference of 1.7%. They weigh essentially the same, 91.9 kg/m and 92.9 kg/m. Both are about 252 mm deep, so either fits the same construction zone.
| Property | SHS 250×250×12.5 SHS Hot-finished | SHS 254×254×12.7 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 91.9 kg/m | 92.9 kg/m | -1.1% |
| Depth | 250 mm | 254 mm | -1.6% |
| Width | 250 mm | 254 mm | -1.6% |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 117 cm² | 116 cm² | +0.9% |
| Second moment, major (Iy) | 10,900 cm⁴ | 10,830 cm⁴ | +0.6% |
| Plastic modulus, major (Wpl,y) | 1,040 cm³ | 1,023 cm³ | +1.7% |
| Elastic modulus, major (Wel,y) | 873 cm³ | 853 cm³ | +2.3% |
| Second moment, minor (Iz) | 10,900 cm⁴ | 10,830 cm⁴ | +0.6% |
| Plastic modulus, minor (Wpl,z) | 1,040 cm³ | 1,023 cm³ | +1.7% |
| Radius of gyration, minor (iz) | 9.66 cm | 9.68 cm | -0.2% |
| Torsion constant (It) | 17,200 cm⁴ | 18,420 cm⁴ | -6.6% |
SHS 250×250×12.5 to BS EN 10210-2:2006; SHS 254×254×12.7 to EN 10219 · Continental Steel. Difference is expressed relative to SHS 254×254×12.7.
How to choose between them
On stiffness, SHS 250×250×12.5 has the larger second moment of area: 10,900 cm⁴ against 10,830 cm⁴, a difference of 0.6%. 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 250×250×12.5 is the more efficient section: 11.3 against 11.0 cm³ per kg/m, 2.8% 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 Cold-formed 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, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.