SHS 140×140×10 vs SHS 150×150×9
SHS 140×140×10 is an SHS Hot-finished section from the UK Blue Book (SCI P363); SHS 150×150×9 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 246 cm³ against 248 cm³ of plastic modulus, a difference of 0.8%. They weigh essentially the same, 40 kg/m and 40.52 kg/m. SHS 150×150×9 is deeper, 150 mm against 140 mm, which matters where the floor zone is tight.
| Property | SHS 140×140×10 SHS Hot-finished | SHS 150×150×9 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 40 kg/m | 40.5 kg/m | -1.3% |
| Depth | 140 mm | 150 mm | -6.7% |
| Width | 140 mm | 150 mm | -6.7% |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 50.9 cm² | 48 cm² | +6.0% |
| Second moment, major (Iy) | 1,420 cm⁴ | 1,537 cm⁴ | -7.6% |
| Plastic modulus, major (Wpl,y) | 246 cm³ | 248 cm³ | -0.8% |
| Elastic modulus, major (Wel,y) | 202 cm³ | 205 cm³ | -1.5% |
| Second moment, minor (Iz) | 1,420 cm⁴ | 1,537 cm⁴ | -7.6% |
| Plastic modulus, minor (Wpl,z) | 246 cm³ | 248 cm³ | -0.8% |
| Radius of gyration, minor (iz) | 5.27 cm | 5.66 cm | -6.9% |
| Torsion constant (It) | 2,270 cm⁴ | 2,608 cm⁴ | -13.0% |
SHS 140×140×10 to BS EN 10210-2:2006; SHS 150×150×9 to EN 10219 · Continental Steel. Difference is expressed relative to SHS 150×150×9.
How to choose between them
On stiffness, SHS 150×150×9 has the larger second moment of area: 1,537 cm⁴ against 1,420 cm⁴, a difference of 7.6%. 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, the two are equally efficient (6.2 against 6.1 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.
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.