SHS 140×140×8.8 vs CF SHS 140×140×10
SHS 140×140×8.8 is an SHS Hot-finished section from the UK Blue Book (SCI P363); CF SHS 140×140×10 is the closest equivalent in the UK Blue Book (SCI P363). CF SHS 140×140×10 carries more bending: 230 cm³ of plastic modulus against 221 cm³, 3.9% more. SHS 140×140×8.8 is the lighter of the two at 35.6 kg/m against 38.1 kg/m, a saving of 6.6% on steel weight. Both are about 140 mm deep, so either fits the same construction zone.
| Property | SHS 140×140×8.8 SHS Hot-finished | CF SHS 140×140×10 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 35.6 kg/m | 38.1 kg/m | -6.6% |
| Depth | 140 mm | 140 mm | same |
| Width | 140 mm | 140 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 45.4 cm² | 48.6 cm² | -6.6% |
| Second moment, major (Iy) | 1,290 cm⁴ | 1,310 cm⁴ | -1.5% |
| Plastic modulus, major (Wpl,y) | 221 cm³ | 230 cm³ | -3.9% |
| Elastic modulus, major (Wel,y) | 184 cm³ | 187 cm³ | -1.6% |
| Second moment, minor (Iz) | 1,290 cm⁴ | 1,310 cm⁴ | -1.5% |
| Plastic modulus, minor (Wpl,z) | 221 cm³ | 230 cm³ | -3.9% |
| Radius of gyration, minor (iz) | 5.33 cm | 5.2 cm | +2.5% |
| Torsion constant (It) | 2,050 cm⁴ | 2,270 cm⁴ | -9.7% |
SHS 140×140×8.8 to BS EN 10210-2:2006; CF SHS 140×140×10 to BS EN 10219-2:2006. Difference is expressed relative to CF SHS 140×140×10.
How to choose between them
On stiffness, CF SHS 140×140×10 has the larger second moment of area: 1,310 cm⁴ against 1,290 cm⁴, a difference of 1.5%. 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 of steel, SHS 140×140×8.8 is the more efficient section: 6.2 against 6.0 cm³ per kg/m, 2.8% better. Over a floor of repeated beams that difference is real tonnage, though it is often outweighed by whichever section the fabricator can actually source.
In short, CF SHS 140×140×10 is the stronger section and SHS 140×140×8.8 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.