SHS 250×250×6.3 vs CF SHS 250×250×6.3
SHS 250×250×6.3 is an SHS Hot-finished section from the UK Blue Book (SCI P363); CF SHS 250×250×6.3 is the closest equivalent in the UK Blue Book (SCI P363). SHS 250×250×6.3 carries more bending: 556 cm³ of plastic modulus against 544 cm³, 2.2% more. They weigh essentially the same, 47.9 kg/m and 47.1 kg/m. Both are about 250 mm deep, so either fits the same construction zone.
| Property | SHS 250×250×6.3 SHS Hot-finished | CF SHS 250×250×6.3 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 47.9 kg/m | 47.1 kg/m | +1.7% |
| Depth | 250 mm | 250 mm | same |
| Width | 250 mm | 250 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 61 cm² | 60 cm² | +1.7% |
| Second moment, major (Iy) | 6,010 cm⁴ | 5,870 cm⁴ | +2.4% |
| Plastic modulus, major (Wpl,y) | 556 cm³ | 544 cm³ | +2.2% |
| Elastic modulus, major (Wel,y) | 481 cm³ | 470 cm³ | +2.3% |
| Second moment, minor (Iz) | 6,010 cm⁴ | 5,870 cm⁴ | +2.4% |
| Plastic modulus, minor (Wpl,z) | 556 cm³ | 544 cm³ | +2.2% |
| Radius of gyration, minor (iz) | 9.93 cm | 9.89 cm | +0.4% |
| Torsion constant (It) | 9,240 cm⁴ | 9,290 cm⁴ | -0.5% |
SHS 250×250×6.3 to BS EN 10210-2:2006; CF SHS 250×250×6.3 to BS EN 10219-2:2006. Difference is expressed relative to CF SHS 250×250×6.3.
How to choose between them
On stiffness, SHS 250×250×6.3 has the larger second moment of area: 6,010 cm⁴ against 5,870 cm⁴, a difference of 2.4%. 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 (11.6 against 11.5 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.
In short, SHS 250×250×6.3 is the stronger section and CF SHS 250×250×6.3 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.