SHS 200×200×8.8 vs SHS 200×200×9
SHS 200×200×8.8 is an SHS Hot-finished section from the UK Blue Book (SCI P363); SHS 200×200×9 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 474 cm³ against 465 cm³ of plastic modulus, a difference of 1.9%. They weigh essentially the same, 52.2 kg/m and 52.3 kg/m. Both are about 200 mm deep, so either fits the same construction zone.
| Property | SHS 200×200×8.8 SHS Hot-finished | SHS 200×200×9 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 52.2 kg/m | 52.3 kg/m | -0.2% |
| Depth | 200 mm | 200 mm | same |
| Width | 200 mm | 200 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 66.5 cm² | 66 cm² | +0.8% |
| Second moment, major (Iy) | 4,020 cm⁴ | 3,918 cm⁴ | +2.6% |
| Plastic modulus, major (Wpl,y) | 474 cm³ | 465 cm³ | +1.9% |
| Elastic modulus, major (Wel,y) | 402 cm³ | 392 cm³ | +2.6% |
| Second moment, minor (Iz) | 4,020 cm⁴ | 3,918 cm⁴ | +2.6% |
| Plastic modulus, minor (Wpl,z) | 474 cm³ | 465 cm³ | +1.9% |
| Radius of gyration, minor (iz) | 7.78 cm | 7.71 cm | +0.9% |
| Torsion constant (It) | 6,290 cm⁴ | 6,454 cm⁴ | -2.5% |
SHS 200×200×8.8 to BS EN 10210-2:2006; SHS 200×200×9 to EN 10219 · Continental Steel. Difference is expressed relative to SHS 200×200×9.
How to choose between them
On stiffness, SHS 200×200×8.8 has the larger second moment of area: 4,020 cm⁴ against 3,918 cm⁴, a difference of 2.6%. 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 200×200×8.8 is the more efficient section: 9.1 against 8.9 cm³ per kg/m, 2.1% 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, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.