SHS 160×160×5 vs SHS 150×150×6
SHS 160×160×5 is an SHS Hot-finished section from the UK Blue Book (SCI P363); SHS 150×150×6 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 178 cm³ against 180 cm³ of plastic modulus, a difference of 1.1%. SHS 160×160×5 is the lighter of the two at 24.1 kg/m against 26.4 kg/m, a saving of 8.7% on steel weight. SHS 160×160×5 is deeper, 160 mm against 150 mm, which matters where the floor zone is tight.
| Property | SHS 160×160×5 SHS Hot-finished | SHS 150×150×6 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 24.1 kg/m | 26.4 kg/m | -8.7% |
| Depth | 160 mm | 150 mm | +6.7% |
| Width | 160 mm | 150 mm | +6.7% |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 30.7 cm² | 33.6 cm² | -8.6% |
| Second moment, major (Iy) | 1,230 cm⁴ | 1,146 cm⁴ | +7.3% |
| Plastic modulus, major (Wpl,y) | 178 cm³ | 180 cm³ | -1.1% |
| Elastic modulus, major (Wel,y) | 153 cm³ | 153 cm³ | same |
| Second moment, minor (Iz) | 1,230 cm⁴ | 1,146 cm⁴ | +7.3% |
| Plastic modulus, minor (Wpl,z) | 178 cm³ | 180 cm³ | -1.1% |
| Radius of gyration, minor (iz) | 6.31 cm | 5.84 cm | +8.0% |
| Torsion constant (It) | 1,890 cm⁴ | 1,833 cm⁴ | +3.1% |
SHS 160×160×5 to BS EN 10210-2:2006; SHS 150×150×6 to EN 10219 · Continental Steel. Difference is expressed relative to SHS 150×150×6.
How to choose between them
On stiffness, SHS 160×160×5 has the larger second moment of area: 1,230 cm⁴ against 1,146 cm⁴, a difference of 7.3%. 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 160×160×5 is the more efficient section: 7.4 against 6.8 cm³ per kg/m, 8.3% 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.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. SHS Hot-finished sections are specified to BS EN 10210-2:2006 and SHS Cold-formed to EN 10219 · Continental Steel; the steel grades, tolerances and available lengths differ, connection details and bolt gauges are set out differently, and the two are rarely both stocked in the same market. Check availability before changing a section on a drawing to save 8.7% weight.
In short, SHS 150×150×6 is the stronger section and SHS 160×160×5 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.