CHS 139.7×10 vs CF CHS 139.7×10
CHS 139.7×10 is an CHS Hot-finished section from the UK Blue Book (SCI P363); CF CHS 139.7×10 is the closest equivalent in the UK Blue Book (SCI P363). They are close to interchangeable in bending: 169 cm³ against 169 cm³ of plastic modulus, a difference of 0.0%. They weigh essentially the same, 32 kg/m and 32 kg/m. Both are about 140 mm deep, so either fits the same construction zone.
| Property | CHS 139.7×10 CHS Hot-finished | CF CHS 139.7×10 CHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 32 kg/m | 32 kg/m | same |
| Depth | 139.7 mm | 139.7 mm | same |
| Width | 139.7 mm | 139.7 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 40.7 cm² | 40.7 cm² | same |
| Second moment, major (Iy) | 862 cm⁴ | 862 cm⁴ | same |
| Plastic modulus, major (Wpl,y) | 169 cm³ | 169 cm³ | same |
| Elastic modulus, major (Wel,y) | 123 cm³ | 123 cm³ | same |
| Second moment, minor (Iz) | 862 cm⁴ | 862 cm⁴ | same |
| Plastic modulus, minor (Wpl,z) | 169 cm³ | 169 cm³ | same |
| Radius of gyration, minor (iz) | 4.6 cm | 4.6 cm | same |
| Torsion constant (It) | 1,720 cm⁴ | 1,720 cm⁴ | same |
CHS 139.7×10 to BS EN 10210-2:2006; CF CHS 139.7×10 to BS EN 10219-2:2006. Difference is expressed relative to CF CHS 139.7×10.
How to choose between them
On stiffness, CF CHS 139.7×10 has the larger second moment of area: 862 cm⁴ against 862 cm⁴, a difference of 0.0%. 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 (5.3 against 5.3 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.