SHS 180×180×5 vs CF SHS 180×180×5
SHS 180×180×5 is an SHS Hot-finished section from the UK Blue Book (SCI P363); CF SHS 180×180×5 is the closest equivalent in the UK Blue Book (SCI P363). They are close to interchangeable in bending: 227 cm³ against 224 cm³ of plastic modulus, a difference of 1.3%. They weigh essentially the same, 27.3 kg/m and 27 kg/m. Both are about 180 mm deep, so either fits the same construction zone.
| Property | SHS 180×180×5 SHS Hot-finished | CF SHS 180×180×5 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 27.3 kg/m | 27 kg/m | +1.1% |
| Depth | 180 mm | 180 mm | same |
| Width | 180 mm | 180 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 34.7 cm² | 34.4 cm² | +0.9% |
| Second moment, major (Iy) | 1,770 cm⁴ | 1,740 cm⁴ | +1.7% |
| Plastic modulus, major (Wpl,y) | 227 cm³ | 224 cm³ | +1.3% |
| Elastic modulus, major (Wel,y) | 196 cm³ | 193 cm³ | +1.6% |
| Second moment, minor (Iz) | 1,770 cm⁴ | 1,740 cm⁴ | +1.7% |
| Plastic modulus, minor (Wpl,z) | 227 cm³ | 224 cm³ | +1.3% |
| Radius of gyration, minor (iz) | 7.13 cm | 7.11 cm | +0.3% |
| Torsion constant (It) | 2,720 cm⁴ | 2,720 cm⁴ | same |
SHS 180×180×5 to BS EN 10210-2:2006; CF SHS 180×180×5 to BS EN 10219-2:2006. Difference is expressed relative to CF SHS 180×180×5.
How to choose between them
On stiffness, SHS 180×180×5 has the larger second moment of area: 1,770 cm⁴ against 1,740 cm⁴, a difference of 1.7%. 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 (8.3 against 8.3 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, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.