SHS 350×350×14.2 vs SHS 350×350×16
SHS 350×350×14.2 is an SHS Hot-finished section from the UK Blue Book (SCI P363); SHS 350×350×16 is the closest equivalent in the European (Continental) range. SHS 350×350×16 carries more bending: 2488 cm³ of plastic modulus against 2360 cm³, 5.1% more. SHS 350×350×14.2 is the lighter of the two at 148 kg/m against 163 kg/m, a saving of 9.2% on steel weight. Both are about 350 mm deep, so either fits the same construction zone.
| Property | SHS 350×350×14.2 SHS Hot-finished | SHS 350×350×16 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 148 kg/m | 163 kg/m | -9.2% |
| Depth | 350 mm | 350 mm | same |
| Width | 350 mm | 350 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 189 cm² | 203 cm² | -6.9% |
| Second moment, major (Iy) | 35,200 cm⁴ | 36,510 cm⁴ | -3.6% |
| Plastic modulus, major (Wpl,y) | 2,360 cm³ | 2,488 cm³ | -5.1% |
| Elastic modulus, major (Wel,y) | 2,010 cm³ | 2,086 cm³ | -3.6% |
| Second moment, minor (Iz) | 35,200 cm⁴ | 36,510 cm⁴ | -3.6% |
| Plastic modulus, minor (Wpl,z) | 2,360 cm³ | 2,488 cm³ | -5.1% |
| Radius of gyration, minor (iz) | 13.7 cm | 13.4 cm | +2.2% |
| Torsion constant (It) | 54,900 cm⁴ | 61,480 cm⁴ | -10.7% |
SHS 350×350×14.2 to BS EN 10210-2:2006; SHS 350×350×16 to EN 10219 · Continental Steel. Difference is expressed relative to SHS 350×350×16.
How to choose between them
On stiffness, SHS 350×350×16 has the larger second moment of area: 36,510 cm⁴ against 35,200 cm⁴, a difference of 3.6%. 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 350×350×14.2 is the more efficient section: 15.9 against 15.3 cm³ per kg/m, 4.5% 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 9.2% weight.
In short, SHS 350×350×16 is the stronger section and SHS 350×350×14.2 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.