SHS 200×200×12.5 vs SHS 203×203×12.7
SHS 200×200×12.5 is an SHS Hot-finished section from the UK Blue Book (SCI P363); SHS 203×203×12.7 is the closest equivalent in the European (Continental) range. SHS 200×200×12.5 carries more bending: 643 cm³ of plastic modulus against 621 cm³, 3.5% more. They weigh essentially the same, 72.3 kg/m and 72.6 kg/m. Both are about 202 mm deep, so either fits the same construction zone.
| Property | SHS 200×200×12.5 SHS Hot-finished | SHS 203×203×12.7 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 72.3 kg/m | 72.6 kg/m | -0.4% |
| Depth | 200 mm | 203 mm | -1.5% |
| Width | 200 mm | 203 mm | -1.5% |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 92.1 cm² | 89.7 cm² | +2.7% |
| Second moment, major (Iy) | 5,340 cm⁴ | 5,161 cm⁴ | +3.5% |
| Plastic modulus, major (Wpl,y) | 643 cm³ | 621 cm³ | +3.5% |
| Elastic modulus, major (Wel,y) | 534 cm³ | 508 cm³ | +5.1% |
| Second moment, minor (Iz) | 5,340 cm⁴ | 5,161 cm⁴ | +3.5% |
| Plastic modulus, minor (Wpl,z) | 643 cm³ | 621 cm³ | +3.5% |
| Radius of gyration, minor (iz) | 7.61 cm | 7.58 cm | +0.4% |
| Torsion constant (It) | 8,490 cm⁴ | 9,030 cm⁴ | -6.0% |
SHS 200×200×12.5 to BS EN 10210-2:2006; SHS 203×203×12.7 to EN 10219 · Continental Steel. Difference is expressed relative to SHS 203×203×12.7.
How to choose between them
On stiffness, SHS 200×200×12.5 has the larger second moment of area: 5,340 cm⁴ against 5,161 cm⁴, a difference of 3.5%. 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 200×200×12.5 is the more efficient section: 8.9 against 8.6 cm³ per kg/m, 4.0% 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 a marginal amount of weight.
In short, SHS 200×200×12.5 is the stronger section and SHS 200×200×12.5 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.