SHS 300×300×10 vs CF SHS 300×300×10
SHS 300×300×10 is an SHS Hot-finished section from the UK Blue Book (SCI P363); CF SHS 300×300×10 is the closest equivalent in the UK Blue Book (SCI P363). SHS 300×300×10 carries more bending: 1250 cm³ of plastic modulus against 1210 cm³, 3.3% more. CF SHS 300×300×10 is the lighter of the two at 88.4 kg/m against 90.2 kg/m, a saving of 2.0% on steel weight. Both are about 300 mm deep, so either fits the same construction zone.
| Property | SHS 300×300×10 SHS Hot-finished | CF SHS 300×300×10 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 90.2 kg/m | 88.4 kg/m | +2.0% |
| Depth | 300 mm | 300 mm | same |
| Width | 300 mm | 300 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 115 cm² | 113 cm² | +1.8% |
| Second moment, major (Iy) | 16,000 cm⁴ | 15,500 cm⁴ | +3.2% |
| Plastic modulus, major (Wpl,y) | 1,250 cm³ | 1,210 cm³ | +3.3% |
| Elastic modulus, major (Wel,y) | 1,070 cm³ | 1,040 cm³ | +2.9% |
| Second moment, minor (Iz) | 16,000 cm⁴ | 15,500 cm⁴ | +3.2% |
| Plastic modulus, minor (Wpl,z) | 1,250 cm³ | 1,210 cm³ | +3.3% |
| Radius of gyration, minor (iz) | 11.8 cm | 11.7 cm | +0.9% |
| Torsion constant (It) | 24,800 cm⁴ | 25,000 cm⁴ | -0.8% |
SHS 300×300×10 to BS EN 10210-2:2006; CF SHS 300×300×10 to BS EN 10219-2:2006. Difference is expressed relative to CF SHS 300×300×10.
How to choose between them
On stiffness, SHS 300×300×10 has the larger second moment of area: 16,000 cm⁴ against 15,500 cm⁴, a difference of 3.2%. 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, the two are equally efficient (13.9 against 13.7 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 300×300×10 is the stronger section and CF SHS 300×300×10 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.